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About this book

This volume includes selected and reviewed papers from the 4th International Congress of Automotive and Transport Engineering, held in Cluj, Romania, in September 2018. Authors are experts from research, industry and universities coming from 14 countries worldwide. The papers are covering the latest developments in automotive vehicles and environment, advanced transport systems and road traffic, heavy and special vehicles, new materials, manufacturing technologies and logistics, accident research and analysis and innovative solutions for automotive vehicles.

The conference is organized by SIAR (Society of Automotive Engineers from Romania) in cooperation with FISITA.

Table of Contents

Frontmatter

Advanced Engineering, Software and Simulation

Frontmatter

Modeling and Simulation of the Specific Mechanisms Used in Convertible Automobiles

The paper deals with linkages used to actuate the retractable top of convertible passenger car, which are either a simple articulated 4-bar mechanism or a stacking multi-contour n-bar mechanism. The car top that can fold or unfold is consisting of two or three hard components or flexible material as textile. In the case of flexible top, the folding space is smaller, occupying only a relative small volume of the trunk. The folding linkage of the hard top is a planar kinematic chain with articulated bars which allows the two or three top parts to be stacked into the trunk room. To be observed that the first hard component of the kinematic chain is the car rear screen and the second hard part is actually the retractable top. In order to fold the car top and the rear screen, the door trunk is actuated by means of a simple hinge pair or a 4-bar mechanism. In the case of a larger passenger car, the top consists of two parts and together with the rear screen form the open kinematic chain which can be closed by means of some stacked kinematic chains. Using CAD modeling and kinematic simulation of the retractable textile car top linkage used on convertibles, the mechanism efficiency regarding its operation can be improved. Through Inventor® software the user can modify any part or subassembly of the mechanism at any moment. This can be done by means of the parametric design which allows that any changing on a component to be instantaneous reflected on the assembly which that part belongs to.

Daniela Antonescu, Daniel Iozsa, Ovidiu Antonescu, Gheorghe Fratila

Using Inertial Sensors in Driver Posture Tracking Systems

Improving position of car drivers leads to superior driving performance. Ensuring an ideal position can be achieved by real-time tracking and evaluation of the driver’s posture. Thus, this paper proposes a lower-body tracking system using inertial sensors. The developed equipment has the ability to compare the driver’s posture at a given moment with an ideal posture, recorded in the calibration phase, with hardware equipment. In order to compare and evaluate the driver’s postures during driving the car, a mathematical model of the human body has been developed, having as input data the measurements realized with the inertial sensors. This product contains great added value (software component) on a hardware structure (parts such as: smartphone, inertial sensors and controller) which already exists on the market.

Silviu Butnariu, Gheorghe Mogan, Csaba Antonya

CFD Simulation of Turbulent Flow Around a Shrouded Spur Gear for Predicting Load-Independent Windage Power Losses

Load-independent power losses, namely windage power losses, are of big concern when the gearbox is loaded without oil lubrication. Air and/or oil mist are the fluid medium and should be studied before the addition of oil churning and squeezing losses. In this study, firstly, two dimensional computational fluid dynamics (CFD) approaches are followed to understand the behavior of the medium around the shrouded, rotating spur gear for the 40 teeth geometry of Seetharaman and Kahraman. For the sake of simplicity and fast convergence, periodic boundary conditions are employed with addition of carefully selected turbulence models in ANSYS Fluent 18.2. In the second part, same boundary conditions are applied to three dimensional study for the 23 teeth geometry of Seetharaman and Kahraman. Secondary flows and pressure contours are captured well. Windage power loss calculations are compared with the numerical study of Chaari et al. for different angular velocities for two-dimensions. As the result, qualitative behavior of windage power loss change vs. angular velocities matched well with the literature. Currently, three dimensional single spur gear and spur gear pairs are studied for the calculation of windage power losses. They will be compared with experimental data of Seetharaman and Kahraman.

Emre Kara, Ömer Fırat Nas, Nihat Yıldırım

Numerical Investigation of Slant Angle Effect on a Simplified Car Model with Solution Adaptive Cartesian Grid Method

In automotive industry, selection of slant angle of a car can be aerodynamically problematic. As the simplest case, a generic Ahmed body car model is used to show the effect of slant angle on the aerodynamic outputs of the flow around it. Pressure coefficient distributions are calculated numerically and wake vortices are captured by use of a solution adaptive Cartesian grid based CFD solver. Roe’s Riemann solver is employed for iteratively simulating the flow. Multi-grid methods are implied in the flow solver for faster convergence rates. Results at 25° slant angle are compared with experimental data from literature for validation and Ansys FLUENT results for verification. As the future work, this study can be extended to solve three dimensional boundary layer interactions around the car model and experimental setup can be designed for self-validating the CFD results.

Emre Kara

Control of Injection Process Using Irate Injection Law on Single Cylinder Diesel Engine’s by Numerical Simulation

Injection process control for internal combustion engines ensures optimal operating conditions regardless of engine load conditions or environmental conditions. Optimization of the injection process has a major impact on the efficiency of engine processes by increasing engine power and torque, reducing fuel consumption and pollutant emissions. This paper proposes a numerical analysis of the injection process by modeling and computer simulation of single-cylinder engine 5402 AVL, based on multiple fuel injections. To achieve the proposed objective, the virtual model for the AVL 5402 experimental single-cylinder engine was created in the AVL Boost simulation application, model for which the AVL MCC combustion model governed by the iRate injection law was implemented. In order to achieve the proposed computerized simulations, the developed studying methodology is based on the division of injection process into multiple sequences, starting from a well-defined amount of fuel for each engine speed and load value. In the first case, the engine functionality is monitored in the case of an injection process consisting of a pilot injection and a main injection. In the second case, the engine functionality is monitored in the case of an injection process consisting of two pilot injections and a main injection. In the third case, the engine functionality is monitored in the case of an injection process consisting of two pilot injections and two main injections.

Iclodean Calin, Solcan Vasile, Craciunescu Marian, Mariasiu Florin, Jurchis Bogdan

Lateral Impact Behavior Study of a Car Door

Side impact collision is one of the most important challenges faced today by the automotive industry. This leads to a significant interest in the field of side impact protection by international car manufacturers and regulators. This article will present and study the effects produced during a lateral impact on a small impact area, the lateral impact with a pole impact. In the real world, impacts on small surfaces are collisions with rigid objects along the roadside, for example, trees and pillars. These accidents are dangerous and the frequency of deaths or serious injuries due to lateral impact is high. Studies have shown that the main cause of injury to persons in side impact collisions can be attributed to unwanted intrusion of a side panel in the passenger compartment. Nearby occupants are four times more likely to suffer serious or fatal injuries. The lateral impact is modeled on the passive safety rules that make the study base of a European organization, Euro NCAP. The primary objective in side impact is to maximize energy absorption and minimize injury to the occupant.

Manea Ana Maria, Iozsa Daniel, David Victor-Costin, Stan Cornelia

Study on the Contact Stress Between the Piston-Ball and the Swash Plate for an Axial Hydrostatic Motor

The main purpose of this study is to analyze the contact stresses at the interface between the piston-balls and the swash plate of the axial hydrostatic motor, for two constructive solutions. Contact problems are highly nonlinear and required significant resources to solve. In this study, three-dimensional elastic-plastic stress analysis of sliding contact is conducted on 3D piston-swash plate model. The contact pressure distributions are calculated using elastic Hertz theory and finite element method for two constructive solutions. For every solution it was analyzed the influence of the geometric dimensions of the parts in contact.

Sebastian Radu, Horia Abăităncei, Cristi Irimia, Mihail Grovu, Călin Husar

Topography Optimization of a Bracket Used for Car Bodywork Reinforcement

Nowadays the methods and procedures for optimization of the mechanical structures are integrated in CAD and FEM software. Implementation of optimization algorithms in design process helps the designer to find the best shape that can fulfill the mechanical requirements without involving additional calculation, time and specialized personal. This study shows the necessary steps to find the optimal shape of the bracket used to rigidize the car bodywork, by using the topographic optimization method. The base geometry is modeled in Solidworks CAD environment. The midsurface of this geometry is extracted and meshed into shell finite elements using Hypermesh software. The assigned material properties and load case creation are done after the establishing the design and nondesign space and the objective functions. The finite element model is run in Optistruct solver. The obtained frequencies for six-vibration mode are analyzed between the initial and optimized model. The best-resulted geometry is generated with the manufacturing purpose. The end of this paper highlight the advantages of using optimization in automotive design engineering.

Iacob-Liviu Scurtu, Monica-Carmen Balcau, Ancuta-Nadia Jurco

The Aerodynamic Study of a Body Truck

Nowadays, the required standards of automotive manufacturing involves complex studies with purpose of the fuel and noise reduction produced by the autovehicles in functioning. Shape optimization of the car body involves lowering the aerodynamic force on the car; the airflow must be have a more laminar distribution. The aims of this study are to determine the airflow distribution in functioning of the truck with trailer and the method to decreasing the drag coefficient. In the first part of the paper are presented the studies and graphical methods used to determine the airflow simulation. Using the CAD design and the modeling techniques, the body shape of the truck with trailer is modeled in SolidWorks software. The geometry is inserted in a virtual wind tunnel created in the Flow Simulation module. The virtual environment created imitates the real working conditions. The aerodynamic model is tested on the 25 m/s velocity of the truck. After running the simulation, the obtained results are analyzed and the shape of the truck is improved with air deflectors in the space between the cabin and trailer. Rear side of the trailer is slanted to reduce the swirl flow and the vacuum volume. All obtained result are compared, establishing the optimal geometry of the bodywork. The end of this study presents the conclusions and the future research.

Bodea Sanda-Mariana, Prodan Calin-Vasile, Scurtu Iacob-Liviu

Simulink Model to Optimize Cab Suspension

An important feature in designing a truck’s cab is the driver’s comfort. Through cabin architecture it is intended to optimize its behaviour in all modes of operation of the vehicle.Experimental studies to improve comfort parameters are laborious, require significant time and costs. The study proposes and uses a model developed in the Simulink Matlab program, which takes into account the elastic system of the truck and the cabin suspension system. The simple model allows the changement of the input parameters - road parameters - and the variation of the elastic and damping characteristics of the cabin to improve the behaviour and comfort. The results obtained by simulation are compared with experimental data. Suspension performance was analyzed for two type of road obstacle: a threshold and a step-down.The study of the optimization of the cabin mounting system was achieved by modifying the values of the elastic characteristics and the damping in the model.The model is also likely to be developed and used to study the dynamic behaviour of truck structures in different working regimes.

Cornelia Stan, Daniel Iozsa

The Impact of the Wheel’s Rim on the Aerodynamics of Passenger Vehicles

The purpose of this Paper is to investigate the amount of aerodynamic energy consumed by the wheels and the impact on the overall drag of a passenger vehicle. The wheel parts (rim, tire and cap) were modeled and aerodynamically analyzed using a finite element Computational Fluid Dynamics (CFD) software. To highlight the wheel’s potential in the overall aerodynamic drag the rim’s useful area is modified by decreasing the porosity in a progressive manner. The CFD simulation results are presented using Iso-Lambda and Iso-Cpi, parameters together with coefficients like total pressure deficit, skin friction and vorticity magnitude. An important conclusion of the study was the fact that by blocking the flow thru the rim, an aerodynamic potential can be achieved. Careful design of wheels may lead to significant reduction in drag and improvements of vehicle drag coefficient. This would generate lower fuel consumption and important CO2 reduction, leading to a more environmentally friendly vehicle. The work will be continued by extending the analysis towards commercial vehicles like heavy trucks that have a significant number of wheels and are more exposed to air flow. Improvements in this area may lead to a significant reduction in fuel consumption. It should be pointed out that CFD is a good method for developing and optimizing solutions but has to be reinforced by physical tests performed on road or in wind tunnels.

Laurentiu Ilea, Daniel Iozsa, Cornelia Stan, Gheorghe Fratila

Virtual Determinations and Analyzes on the Influence of the MRD Magnetic Field from the Vehicle Structure in Assessing the Passenger Comfort During Travel

The magnetorheological damping systems due to the relatively simple operating principle, but especially due to the efficiency of the functioning as compared to other types of shock absorbers, tend to occupy a wider range of use. In the field of motor vehicles, they are used for the shock and vibration damping systems, generated when traveling on roads with a non-uniform structure. With the change in vehicle development strategies, new systems and subsystems performance research is required. The purpose of this research is to identify as accurately as possible the magnetic field values created inside the damper so as to generate increased comfort in the seat for the vehicle’s staff. The correct determination of the current intensity values feeding the damper coil is essential for the accurate understanding of the dynamic behavior of the magnetorheological fluid inside the this. The research is aimed at using two virtual analysis software platforms: AMESim and ANSYS. The programs considered can make very realistic dynamic simulations, but at the same time bring economic efficiency from the point of view of research. The results are considered to be the correct utilization of the behavior of the magnetorheological damper under the influence of the current intensity, due to the dependence of the damping force on the created magnetic field, the amelioration of shocks and vibrations and for the increase of the degree of comfort in the seat.

Mitroi Marian-Florin, Tudor Camil, Turcanu Iulian

Numerical Results Obtained on Models of Dynamical Systems Used in the Study of Active Suspensions

The semi-active and active suspensions are more and more often used in the construction of medium price automotive. The models used by the specialists in the study of the dynamical response of such suspensions are diverse and start from simple models arriving to complex ones. In this paper we perform an analysis of them and of the numerical results obtained by simulation on many models of semi-active and active suspensions. The results are presented as diagrams obtained by using some performance criteria.

Sorin Marcu, Dinel Popa, Nicolae-Doru Stănescu, Nicolae Pandrea

Modeling and Analysis of a Vehicle Suspension

The present paper will be focused on determining the tire-suspension assembly behavior involved in vehicle dynamics for a car through a dedicated model developed in Matlab/Simulink software. The Matlab/Simulink environment will be used, by the last release, 2018a, which offer a dedicated powertrain and vehicle dynamic modules. The analysis will use a model for the tires and a model for the suspension response for a vehicle configuration. The road simulation will be used for a complex analysis of the car response as input in model simulation. Will be expected models and mathematical equations for a complete simulation, with Simulink environment, in order to obtain rapid responses and pre evaluation of complex analysis for car-environment interaction. The study could be applied, in this analysis, only for a dedicated type of suspension, from the geometry point of view, but not limited to the viscosity and cinematic response of the damping assembly. The Matlab/Simulink parametrization will allow multiple ways parameters changing and time response of the model will shorten the analytical studies of vehicle dynamics.

Liviu Mihon, Nicolae Lontiș

Vibrotactile Patterns for Smartphone Based ADAS Warnings

A large number of researches show that various driver distractions considerably increase the probability of causing an accident. Advanced Driver Assistance Systems (ADAS) can be used to prevent dangerous driving conditions by monitoring the environment and warn the user in situations like collision, lane departure or speed infractions. In most cases of using the ADAS systems, the driver is warned by visual indicators or audio signals. This paper investigates the design of a device that can be integrated in the driver’s seat which allows the issue of dynamic vibrotactile warnings received from a smartphone based ADAS system.

Florin Gîrbacia, Gheorghe-Daniel Voinea, Teodora Gîrbacia

Predictive Actuation of a Driving Simulator

Testing of virtual cars in multi-modal virtual environment is an important step in the validation process of new concepts and technologies. A driving simulator with realistic interaction, operating environment and feedback eliminates the difficulties of road test, but allows the understanding of driving behavior, testing driver assistant systems and for traffic research. A static driving simulator is lacking the required displacement and acceleration feedback, but a hexapod motion system can reproduce some of these. The objective of this paper is to present a predictive actuation algorithm for controlling the position of a driving simulator in order to maximize the sensation of displacement and acceleration of the driver. Several driving scenarios are considered and for each an ideal starting point of the motion platform is computed. In case the driver is in the process of approaching a road segment from one the analyzed scenarios, the predictive actuation module will try to move the driver of the simulation platform from the current position towards the ideal position within the perceptibility thresholds.

Csaba Antonya, Laurentiu Carabulea, Cornelia Pauna

Study of Stability on Water for a Special Amphibious Autovehicle

As the automotive industry is in continuos change, moving from a mechanical to a software-intensive industry, an essential part of the development and research process is represented by the computerized modelling and simulation since, this mechanism, provides prediction on how a vehicle will behave in real life situations. For studying and experimentally testing special purpose amphibious vehicles, it is preferable to use software programs, in order to reduce costs and to have a proper look on how a vehicle will work in reality and to avoid the risks of carrying out tests in open water. The scientific aim of this paper is to study the stability of an amphibious vehicle with special purpose through the means of computer-aided-design (CAD) applications software. First of all, a lot of measurement had to be done in order to design 2D sketches, which eventually, will lead to a 3D model of a chosen amphibious vehicle with special purpose, which resembles the one used in reality. Then, in order to study stability, the model was imported to a naval-friendly software and the curves of stability were obtained. In addition, the flooding points of the amphibious vehicle were set. Furthermore, different loading cases were taken into consideration for an equilibrium analysis. Lastly, the process of water entry/exit of the amphibious vehicle was studied using Bonjean Scale.

R. Vilau, A. Stoica, A. Constantinescu, D. Suci

Optimizing the Responsiveness of a Turbocharged Ice Through a New Design of the Exhaust Line

The main goal of the research was to redesign the exhaust line of a Y61 code motored Nissan Patrol in a way that would result in a better throttle response of the engine without replacing the existing turbocharger with a newer design. To achieve this target, enthalpy of exhaust gases entering the turbine had to be increased while cylinder backpressure had to be reduced. To increase exhaust gas enthalpy, exchanged energy between hot gases and the surrounding of the exhaust manifold had to be reduced, while cylinder backpressure was reduced using a 4 in 2 in 1 design of the exhaust manifold. This arrangement takes advantage of greater distance between two consecutive firing, connecting first cylinders one with four, two with three, and then the two resulting gas flows, thus instead of 180 °CA the distance between two consecutive firing being 360 °CA. Both designs (standard and optimized) were modeled in AVL BOOST software and simulations were run to show the benefit of the optimized version.With the optimized design the torque curve of the engine was optimized, having a greater slope of the torque gradient over the 1500–2000 rpm bandwidth, thus improving the time to torque characteristics of the engine.The novelty of the paper consists of the combination of the two design approaches applied to the exhaust line of the engine to achieve the proposed performance gains.

Kocsis Levente, Moldovanu Dan, Baldean Doru, Gaspar Ferenc

Experimental Research on the Use of MRD to Reduce Shocks and Vibrations in Light Car Seats

The trends in the automotive field aim at providing all users with a high level of safety and a high degree of comfort. Current technologies combine increasingly judicious optimal control of most systems in the their componing. Thus, the highest level electronic equipment permanently adjusts the various systems and subsystems of the vehicles. The aim of the research is to determine optimal MRD functionality to reduce extreme shock and vibration values at the driver’s seat during unbuilt or very rough roads. Also, the identifying of these values its to view of correctly determining the supply current of the shock absorber coil so that the magnetic force created can efficiently absorb the accelerations produced beyond the limits allowed by the international standards in force. Carrying out the research involves multiple laboratory tests on MRD using the Hidropuls type, but also some references to vertical seat accelerations values recorded in the real world. The expected results are to reduce physical activity on the spine, as well as increasing the comfort of the seated staff.

Mitroi Marian-Florin, Cerbu Camelia

Green Vehicle Solutions

Frontmatter

Techniques and Procedures for Assessing the Energy Balance of Internal Combustion Engines

Global warming and falling fossil fuel reserves have led to attempts to lower fuel consumption of motor vehicles. The drastic limitation of pollutant emissions of internal combustion engines due to legislative changes has led to widespread use of exhaust gas treatment systems resulting in an increase in the importance of optimizing engine efficiency. In internal combustion engines only about one third of the fuel consumed is converted into effective mechanical work. Much of the fuel’s energy is lost through the exhaust gas (about 30%) and the cooling system (about 20%). If the lost heat could be recovered, it could substantially reduce the fuel consumption, and thus the pollutant emissions of the internal combustion engine. The paper presents the analysis of energy distribution developed by combustion of fuel and measures to be taken to increase the effect of converting the energy of combustible into effective mechanical work.

Bogdan Cornel Benea, Anghel Chiru

Characterization of Sunflower Oil Biodiesel as Alternative for Diesel Fuel

Methyl esters from various vegetable oils have been increasingly used in diesel engines to partially substitute or replace petroleum fuels. In this present study biodiesel was produced from sunflower oil by base-catalyzed transesterification process. A 30 L per batch experimental installation was used to produce biodiesel using a molar ratio of alcohol to oil 6:1, a reaction temperature of 65 °C and a reaction time of 2 h. A characterization and quality evaluation were done by measuring viscosity, flash point, density, fatty acid compositions, elementary and thermal analysis of sunflower oil, sunflower oil biodiesel and petroleum fuel. The results show poor atomization due to the high viscosity with the increase of combustion chamber deposits. Biodiesel has less carbon and hydrogen content than diesel fuel. The process of volatilization for sunflower oil biodiesel initiates and finishes in temperatures that are much higher than diesel.

Dragos Tutunea, Ilie Dumitru, Laurentiu Racila, Oana Otat, Lucian Matei, Ionut Geonea

Research Concerning Fuel Economy Coefficient and Carbon Foot Print in Various Conditions for a City Compact Size Vehicle with Digital Control for a Green Solution and Method at Technical University from Cluj-Napoca

Carbon footprint and automotive pollution are some important concerns in transportation field. Main objective of the present work is to propose, develop and implement the new complex method of computer aided measurement concerning carbon footprint in urban driving condition of a city car with instruments and equipment available at Technical University from Cluj-Napoca (TUCN). Specific objectives consist in experimental research of fuel consumption and economy coefficient, determination of pollutant emissions from the motor vehicle and pointing out the method’s fundamentals at TUCN. Applied research and testing results were gained, stored and fully analyzed with different interpretation tools. There were also highlighted the economy and carbon footprint trend lines in each particular context. Defining the set of expectations in fuel economy coefficient and carbon footprint is tight related to the consumption evaluation and research. Engine operating parameters and exhaust gases are not manifesting in isolation of the whole surrounding environment. The engine, the operating processes and the fuel efficiency should be studied in connection with the complex structure and multitude of influences which happens to be the entire motor vehicle moving on the city roads and impacting the surrounding ambient. The fuel efficiency and carbon footprint aspects have great influence on the vehicle’s use and its regime, but also they have a health and financial impact when it comes to mankind. Research perspectives are shown in order to ease up the further investigations of the outlined problems.

Emilian-Vasile Borza, Doru-Laurean Băldean, Adela-Ioana Borzan

Influence of TiO2 Nano-particles Content on Physicochemical and Tribological Properties of Lubricant Oil

This study deals with research activities that aim to emphasize the effect of titanium dioxide (TiO2) nano-particles, used as additive, on physicochemical and tribological properties of lubricant engine oil. Commercial TiO2 Degussa P25 nano-particles with 21 nm average particle size were blended with commercial Castrol (10W-40, A3/B4, SL/CF) engine oil, varying concentrations of nano-particles (between 0.01% wt. to 0.1% wt.) in lubricating oil, under both magnetic stirring and ultrasound conditions. The physicochemical properties of the oil and dispersions which contain TiO2 nano-particles were determined e.g. density, viscosity, viscosity index and flash point. In order to evaluate if there are chemical interactions between TiO2 nano-particles and oil, FT-IR spectroscopy was utilized. The tribological properties were tested on block-on-ring tribotester. Density, viscosity and viscosity index tend to increase with TiO2 content. The studies provide information regarding the utilization of TiO2 nanoparticles as additive in lubricant engine oil which can improve the physicochemical (density, viscosity and viscosity index) and tribological (coefficient of friction) properties, which can leads to fuel economy in automotive engines.

Andreia Molea, István Barabás, Ramona Suciu

Fuel Properties of Diesel-Ethanol-Tetrahydrofuran Blends: Experimental and Theoretical Approaches

Oil based fuel is the most important energy source in the road transport sector which has an increasing demand of fuel meanwhile its raw material resources are decreasing. Therefore, new fuels and blends are urgently needed. Blends of diesel fuel-ethanol could be one of the solutions. For this its properties must be described properly. To describe density, viscosity and surface tension of these types of fuel, five blends containing 2, 5, 8, 10 and 15% ethanol were prepared and stabilized at 20 °C and 0 °C by using tetrahydrofuran as surfactant. The density and viscosity of blends were measured at 0, 15, 40 and 50 °C and their surface tension was evaluated at 20 °C. In order to characterize the hazardousness of these blends their flash points were measured. The density and viscosity of the blends were mathematically described as a function of their composition and temperature. Surface tension was modelled as a function of ethanol content.

István Barabás, Andreia Molea, Ramona Suciu

Applications of Biogas Inside a Motogenerator – Case Study

Biogas, as a renewable energy carrier, represents one of the possible biofuels which can be further used in firing processes with applications in both thermal and electrical processes. In Europe and worldwide there are developed methods used to capitalize this biofuel relative to its potential use in automotive applications. Romania still has a large gap to cover in terms of using its own biodegradable resources in order to produce suitable biofuels at large scale. With interest relative to this field, the present study involves applications of biogas produced by a pilot installation located at the Mechanical Engineering Faculty Multifunctional Laboratory, Politehnica University, Timisoara, using a moto-generator test rig in order to determine its suitability as a biofuel in small engine applications. The biogas was used as a standalone biofuel for the presented scenarios and the main parameters determined during the tests were: the specific consumption function of injection time, power as a function of injection time, the specific consumption function of advance to spark ignition and emissions of CO and CO2.

Adrian Eugen Cioablă, Virgil Stoica, Francisc Popescu

Biodiesel Production and Sustainability Challenge

Today, energy is an indispensable factor for the developing of the societies and countries. However, most of the energy demand is supplied by fossil fuels which tend to dry up in the next few decades forcing all the authorities to find new alternative sources in order to stabilize their economies. Biodiesel has emerged as an alternative, biodegradable and renewable fuel which can be used in transportation sector without any modifications of internal combustion engines. Biodiesel is analyzed by environmental, social and economic criteria for sustainability analysis. The criteria for biodiesel sustainability are discussed by presenting different indicators, keeping in view the Romanian fuel market and Renewable energy directive. The paper concludes with perspectives and recommendations for biodiesel production and usage in Romania.

Fazal Um Min Allah, Marin Bica, Dragos Tutunea

Temperature Dependence of Densities of Different Biodiesel-Diesel-Alcohol Ternary Blends

In this study, waste cooking oil ethyl ester (biodiesel) was produced via basic transesterification reaction, ethyl ester-diesel-methanol ternary blends including different volume ratios of alcohol (2% and 4%) were prepared, densities of the ternary blends were measured at different temperatures (278.15 K, 283.15 K, 288.15 K, 293.15 K, 298.15 K, 303.15 K, 308.15 K, 313.15 K, 318.15 K, 323.15 K, 328.15 K, and 333.15 K) according to ISO 4787 standard, and the exponential model as a function of temperature was derived using the least squares method to predict density values. Moreover, the exponential model was compared to the well-known linear model, and the reliability of these models was investigated using the density data of rapeseed oil methyl ester-diesel-bioethanol ternary blends measured by Barabás. According to result, the exponential model, suggested by the authors, qualitatively and quantitatively better reflects the variations in densities of different biodiesel-diesel-alcohol ternary blends measured by the authors and Barabás.

Mert Gülüm, Atilla Bilgin

Innovative Methodology for Decreasing Mechanical Losses in Vehicles

An important challenge for vehicle designers is to ensure the greatest possible reduction of energy losses. This specific feature can be accomplished very early, at the stage of design and layout of new products. The objective of this paper is to present innovative, systematic and expanded methodology for research and diminishing of mechanical losses in vehicles. During the implementation of the structure analysis of different design options for new products, we assume main principles, the most important of which are the principles of simplicity and clarity. The improved methodology for decreasing mechanical losses in vehicles includes the following innovative stages: an upgraded design of gearboxes; a new approach for calculating the cardan shaft aiming to diminish its internal dynamic load; a new method for calculating the internal meshing of planetary gear trains with high efficiency. The stages mentioned are based on the research of the authors’ team. A considerable advantage of this methodology is its structure. The application of the methodology improved by the authors’ team enriches the procedures for multivariate design, for analysis and evaluation of conceptual design solutions and makes them more precise.

Antoaneta Dobreva, Vasko Dobrev

Legal Barriers of Utilization of Autonomous Vehicles as Part of Green Mobility

Innovations related to transportation as autonomy of vehicles, connectivity, electrification and shared mobility are already driving substantial transformation in the automotive industry. Powerful mixture of these mobility innovations will positively influence the environmental effect of the transportation and will improve the life quality of millions of people in the next decades. Autonomous or self-driving car is no longer a futurist idea. It exists and can perform in different scenarios successfully. More and more technological solutions are developed to able to fulfil these goals, but the legislative environment is an important enabler as well. In this research, first the main environmental effects as green-house-gas and NOx emissions are considered and later the legal framework is described as a key enabler that can open the door to self-driving cars.

Máté Zöldy

Development of Two-Dimensional Models for Estimating Densities of Biodiesel-Diesel-Alcohol Ternary Blends

Recently, biodiesel has become one of the most significant clean alternative biofuels because of many advantages. However, it has also some shortcomings such as: higher density and viscosity. The high density of biodiesel can cause an increase in the fuel consumption and NOX emissions. In order to overcome this problem, the blending of biodiesel with diesel fuel or alcohols is generally recommended in the existing literature. Although many one-dimensional models are proposed by different authors for predicting fuel properties of biodiesel-diesel binary blends, two-dimensional models are still inadequate for estimating densities of biodiesel-diesel fuel-alcohol ternary blends. Therefore, in this study, (1) densities of waste cooking oil biodiesel-diesel fuel-ethanol ternary blends were measured at different temperatures (278.15 K–343.15 K) according to ISO test method, and (2) some two-dimensional models, previously suggested by the authors, were fitted to the density data of ternary blends obtained from the authors and specialized literature to determine the best correlation for prediction of density. The quadratic surface model is found to be best predictor to estimate densities of ternary blends.

Mert Gülüm, Olusegun David Samuel, Atilla Bilgin

Hybrid and Electric Vehicles

Frontmatter

Comparison and Behavior Analysis in Relation to Autonomy of Urban Driving Cycle for Compact Class Full Electric Vehicle Using ADVISOR Numerical Simulations

Electric vehicle autonomy is a common problem transporting passengers in urban areas. The present paper reveals a comparison and behavior analysis of a compact class vehicle when the urban driving cycle is applied through simulation in ADVISOR open source software. Three types of energy sources on board are proposed and tested through the urban driving cycle on the same full electric vehicle model. Results and interpretations of the autonomy and performances of the full EV are concluding this paper.

Nicolae Stelian Lontis, Liviu Nicolae Mihon

Assessment of Life Cycle Cost for a Plug-in Hybrid Electric Vehicle

The aim of this paper is to develop a computerized simulation of a hybrid vehicle in AVL Cruise software, (based on constructive parameters of Toyota Prius-3rd Generation) to run it on eight different Driving Cycles, and to compare its results. These results will be analyzed from a vehicle performance as well as from a fuel and energy consumption points of view. The cycles used in this paper are: NEDC (New European Driving Cycle), WLTC (Worldwide harmonized Light vehicles Test Cycle), JC08 (Japanese Cycle), FTP-75 (Federal Test Procedure), Australian CUEDC (Composite Urban Emissions Drive Cycle), Artemis Driving Cycle, Chinese C-WTVC (World Transient Vehicle Cycle) and Modem Hyzem. Based on these results, it will be established which driving cycle is the most representative for the actual mobility needs. To create the comparison of these eight driving cycles, it is necessary to evaluate the obtained results on each cycle, and for 100 km and for the entire life span of the vehicle (200000 km, according to 2009/33/CE). The energetic efficiency (fuel and energy consumption) along with pollutant emissions (main emissions calculated based on existing regulations of the considered engine) will be considered.

Denisa Cimerdean, Nicolae Burnete, Calin Iclodean

Numerical Simulation of the Mechanical Models Used for the Coupling of the Power Sources

Mechanical systems used for the coupling of the thermal and electric power sources are a solution used by the constructors in the mechanical structure of the hybrid auto-vehicles. The mechanical systems used in this paper are planetary mechanisms with two degrees of mobility. On a virtual automobile one uses more solutions for the coupling of the power sources for which one performs numerical simulations.

Dinel Popa, Irina Tudor, Nicolae-Doru Stănescu, Claudia-Mari Popa

The Influence Analysis of the Acceleration Regimes on the Specific WLTC Test Cycle Regarding the Fuel Consumption and Pollutant Emissions for a Vehicle Equipped with a GMPDH

It is known that acceleration regimes have a decisive influence on fuel consumption and pollutant emissions. In this sense, the paper highlights the weight with which these regimes contribute to determining the level of fuel consumption and polluting emissions. In the first phase, all acceleration regimes specific to the current WLTC test cycle are selected. Using mathematical modeling with the AMESim platform, the cumulative (CO2 emissions over the cycle) fuel consumption and pollutant emissions of HC, CO, NOx, PM are determined. For comparison, the same magnitudes for the selected acceleration modes are then determined. This highlights the fact that transient acceleration regimes severely affect both fuel consumption and global emissions by determining the magnitude of these influences. This draws attention to the fact that the acceleration regimes specific to the current test cycle still require far-reaching investigations to optimize the powertrain performance for a vehicle equipped with a Diesel Hybrid powertrain.

Gheorghe Bancă, Florian Ivan, Daniel Iozsa, Valentin Nișulescu

Analysis of Range Extended Hybrid Vehicle with Rotary Internal Combustion Engine Using AVL Cruise

The working principle and dynamic characteristics of the range extender hybrid electric vehicle system are first explored. In the second phase, concept and simulation concerns the major part of this work, to develop the rotary internal combustion engine in the AVL Boost engine simulation software to evaluate the fuel consumption. The developed engine is implemented and adapted as a component of the electric vehicle using AVL Cruise driveline simulation software. The rotary internal combustion engine is connected with a generator to create the range extender system. The dynamic model with the configuration of a range extended hybrid electric vehicle is simulated over the New European Driving Cycle (NEDC) driving cycle where the fuel consumption, state of charge of the battery, range of the vehicle is evaluated. Finally, the simulation results in the virtual environment were evaluated and presented. Range extended hybrid vehicles are alternative solutions with comparable performance to electric vehicles.

Bagameri Norbert, Varga Bogdan-Ovidiu, Moldovanu Dan, Csato Aron, Karamousantas Dimitrios

Optimizing Shifting Schedule and Hardware-in-the-Loop Simulation of a Hybrid Vehicle Based on Dual Clutch Transmission

The European Union legislation have introduced regulations on emission reduction for light duty vehicles. Therefore, economy remains a key challenge for automotive engineers. To enable a realistic dual clutch transmission (DCT) system performance evaluation, this paper main objective is development of an IPG Carmaker hybrid vehicle model connected to the testbed with an internal combustion engine by a hardware-in-the-loop (HiL) real time simulation, where the electric powertrain is virtual and it is defined in the application. The specific objective is to develop new shifting schedule of the DCT to optimize the performance of the vehicle. The working principle and dynamic characteristics of the DCT system are first explored. In the second part of the work, the strategy and simulation concern the major part of this work, in order to develop new gear shifting strategy algorithms to evaluate the fuel and electric current consumption over the homologation Worldwide Harmonized Light Vehicles Test Procedure (WLTP) driving cycle. Finally, the simulation results in the HIL environment were evaluated and presented. The constructed model is based on an existing hybrid vehicle. The model was simulated to obtain data regarding the vehicle performance, energy consumption and state of charge on the new WLTP test cycle.

Bagameri Norbert, Varga Bogdan-Ovidiu, Moldovanu Dan, Csato Aron, Karamousantas Dimitrios

Performance Evaluation of an Electric Vehicle in Real Operating Conditions of Quito, Ecuador

The purpose of this paper is show a novel methodology to implement real condition tests for electric vehicles and to assess the performance of electric vehicles in reality in Quito, to compare this to the results from the manufacturer’s standardized tests. Electric vehicles are of particular interest for Ecuador, given its reliance on the importation of refined fossil fuels to satisfy the energy demands from the transport sector. This study assesses the performance, energy consumption, reliability, versatility and running cost of a BYD e6 Electric Vehicle (EV) and the associated Electric Vehicle Supply Equipment (EVSE) in the specific geographic region of Quito, Ecuador. The test driving cycle was performed at different elevations ranging from 1900 to 2850 meters above sea level (m.a.s.l.). All the results were analyzed and compared with respect to the performance of conventional internal combustion engine (ICE) powered vehicles. The total energy needed to fully charge a battery was calculated to be 62.3 kWh, which allowed the vehicle to travel a total distance of 225 km. Overall, the running costs for the e6 under regular use were found to be approximately 50% less than those of conventional internal combustion engine cars.

J. P. Díaz-Samaniego, Jaime Guillén, Daniel Arroyo, Michael Maks Davis

Van Dynamics Performance Analysis for Different Battery Pack Placement

Electric vehicles are the immediate solution to reduce pollutant emissions due to traffic in large urban agglomerations, presenting solutions for electric vehicles designed almost exclusively for personal transport (vehicles). However, in urban traffic there are other types of vehicles needed for the economic activities of an urban agglomeration, vehicles used for goods transport, supply, courier, etc. Transforming these types of vehicles into electric vehicles can be easily achieved by replacing the propulsion unit with the thermal engine with an electric propulsion group, but there is a problem of placing the energy source (battery pack) within the vehicle structure. In order to highlight the effects of energy placement in different locations for a freight vehicle, the work uses the numerical analysis method (CarMaker) to provide a comparable image of dynamic performance and vehicle maneuverability, taking into account the restriction of keeping the same volume of transport capacity. Based on the proposed research methodology, the study can be done for any type of vehicle in urban traffic that is going to be converted into an electric vehicle.

Moldovanu Dan, Varga Bogdan, Mariasiu Florin, Iclodean Calin, Burnete Nicolae Vlad, Mihali Liviu, Ola Sebastian

Manufacturing Technologies and Materials

Frontmatter

Considerations on the Usage of the Same Air Filtration System on Different Engine Types

Automotive manufacturers are equally concerned about cost savings for new vehicles produced and after-sales maintenance cost of the vehicles.A solution applied is to use the same parts (systems) on a wide range of models (vehicles) produced. The air filtration system is such an example. The Renault engines of H4BT 408, 1000 cm3 and K9K 658 use the same air filtration system. The question is whether the maintenance on the system should be different or the same system can be applied.In the paper, new and used origin air filters were tested according to ISO 5011, at the maximum airflow of the engine. During the tests, the restriction of each filter to the different test regimes was measured. The tests were carried out on a laboratory stand. The results were used to determine whether the maintenance schedule applied to the filters leads to premature replacement or the air filters are replaced when they have reached full utilization capacity.

Marius Toma, Adrian Asimopolos

Designing Hybrid BF/FF Epoxy Based Composites with Tailorable Dielectric Properties

The dielectric properties of flax and flax/basalt reinforced epoxy composites were assessed within broad temperatures (25 °C–120 °C) and frequency ranges (from 10–107 Hz). The dielectric relaxation curves based on flax hydrophilicity were drawn and debated individually on samples considered.

Dana Luca Motoc, Radu Tarulescu, Stelian Tarulescu, Adrian Soica

A Comparison Approach to Fire Retardancy Behavior on Tailored Hybrid BF/FF Cyanate-Epoxy Composites

Hybrid composite specimens out of basalt and flax fibers reinforced with a cyanate-ester and epoxy resin combination were subjected to cone evaluation in a cone calorimeter. The increase of the BF layers within the hybrid architectures significantly decrease the pHRR and CO/CO2 released content but not the residues at the end of the combustion process. On the other hand, flax fiber reinforced composites ignite earlier, release a relatively high amount of heat and leaves reduces residues at the end of the combustion process. Further studies on fire-retardant additives deployment within these hybrid structures are expected to boost the flammability outcomes.

Dana Luca Motoc, George Ionut Sava

Experimental Study on the Influence of Using Pistons with Ceramic Crown on Actual Torque and CO Emission

Even though the operating principles of the internal combustion engines have been the same for 125 years, for compression ignition engines and for 151 years or even more, by some authors, for spark ignition- engine builders have tried and managed to improve their performance. One of the methods used was and still is the use of new materials. Among these materials the ceramic materials have a significant role. The present paper aims to find a calculation formula for the actual motor torque of a classic spark ignition engine and with a ceramic crown piston.

I. R. Şugar, M. Banica, L. Giurgiulescu

Comparative Study on the Regeneration of Used Motor Oil

Waste oil is a source of global pollution, both in terms of the amount generated and the environmental toxicity. The used motor oils are contaminated by contaminants and impurities resulted from undesirable oxidation processes: sediment, water, metallic particles and degraded additives. Waste oil recycling is a priority that sums up two important objectives: environmental protection and raw material economy. Also, an important aspect to note is the appropriate management of used engine oil. The waste oil samples used in the study came from different collection stations. The regeneration process used the acid treatment method consisting of the following steps: decantation, acid treatment, sedimentation/decantation, bleaching, neutralization, sedimentation/decantation and filtration. Research has made it possible to compare the results obtained by using several acids (sulfuric acid, acetic acid, nitric acid, phosphoric acid, formic acid) and two whitening methods: by industrial bleaching earth (bentonite) and active charcoal. The main properties for regenerated oils were determined: kinematic viscosity, flash point, specific gravity, TAN and color.The values of the results show their dependence on the acid used and the bleaching process.

Cornelia Stan, Marius Toma, Cristian Andreescu, Daniel Iozsa

Determination of the Tool’s Trajectory for the Manufacturing of the Profile of a Cam

This paper discusses the determination of the position of the cutting tool in the manufacturing process of a cam. The input data are the coordinates of certain points of cam’s profile and the radius of the cutting tool. Using these coordinates, the authors calculate approximates for the coordinates of the center of the osculating circle of the profile of cam at certain positions. The position of the manufacturing tool is determined considering that the tool is tangent at the osculating circle at the contact point. Two variants are selected for the cam: one variant considers the cam as it results in the synthesis process; the second variant considers the cam obtained by applying the Jarvis March in order to be a convex one. For both variants the trajectory of the cutting tool is determined and the obtained numerical results are compared.

Ionuț Dragomir, Nicolae-Doru Stănescu

Use of Mini-Max Approximation for the Determination of the Dependency Between the Input and Output Parameters for the Automotive Parts Obtained by Fused Deposition Modeling (FDM)

Fused Deposition Modeling (FDM) is one of the most used 3D technology for rapid prototyping of different parts. The approach consists in determination of the statistical significance of different parameters using the Analysis of Variance (ANOVA) technique followed by the determination of the correlation laws between the input and output data. These laws are usually described by polynomials obtained with the aid of the Least Squares Method. The use of this method is preferred due to its simplicity, but it has the disadvantage that the error is not known (the only thing we know is that the obtained polynomial leads to the smallest error in the sense of the Least Squares). In our paper we purpose a new approach by using the Tchebyshev polynomials which lead to the mini-max approximation of the law. In this way, the error is always zero in the division points and, moreover, the great advantage is that the error is the smallest one for the entire interval of the input data. The theoretical difficulty of this approach consists in the determination of the division points, while the practical disadvantage is the use of irrational division points for the input data. The formula obtained for the law of variation of the output with respect to the input is the most accurate one in the class of certain polynomials.

Nicolae-Doru Stănescu, Maria-Luiza Beșliu-Gherghescu, Ștefan Tabacu

Dynamic Analysis of a Rotating Structure Manufactured by Fused Deposition Modeling

Given the maturity reached by the Fused Deposition Modeling manufacturing technology the parts should be capable of supporting operating load comparable with parts manufactured using conventional manufacturing methods. The complete manufacturing process is discussed starting form scanning, geometry processing, 3D printing preliminaries and manufacturing process by Fused Deposition Modeling. The final part - engine fan - will be investigated under dynamic load for rapid prototyping and injection molding manufacturing solutions. A numerical model will be used to complete the experimental data.

Diaconescu Claudiu, Tabacu Ştefan, Oltean Alexandru, Pârlac Sebastian

Development of a Material Model for the Use in Life-Time Estimate of Structures

This study is focused on developing of a material capable to be used for numerical prediction of mechanical structures life time. A damage model was implemented starting from a classical stress-strain dataset and it is influence over the results was evaluated. An enhanced analysis of the strain field was achieved by using tensile testing on shaped specimens in conjunction with Digital Image Correlation (DIC). A specialized method, X-Ray Diffraction (XRD), for the investigation of the residual stresses was also used to correlate the strain field with the residual stresses stored by the deformed specimens.

Ionela Alina Sandu, Cătălin Ducu, Sorin Moga, Ştefan Tabacu

Re-sintering Influence on Tribological and Structural Characteristics of Iron-Based Composites for Automotive Applications

Iron-based sintered composites can be used for manufacturing different friction applications for the automotive industry (i.e. brake pads). The present research is a study concerning the influence of the re-sintering on the tribological and structural characteristics of three iron-based friction materials with application in vehicle brake systems. These composites were elaborated by powder metallurgy methods. The chemical composition of the materials contained iron, copper, graphite, nickel, titanium dioxide and/or barium carbonate. First, the three mixtures were homogenized. Green compacts were formed at a compaction pressure of 600 MPa. The sintering was done at 1050 °C, in vacuum for 30 min. The obtained samples were further re-sintered in vacuum, at 1050 °C for 20 min to improve their tribological characteristics. The elaborated materials were characterized by the tribological and structural point of view. The re-sintered samples presented, in general, a higher porosity than the sintered samples. An increase in the friction coefficient was marked out for all three re-sintered materials. Instead, a continuous increase or decrease in the wear rate was not observed. The material that contains titanium dioxide presented the best tribological properties in both sintered and re-sintered states.

Violeta Valentina Merie, Corina Bîrleanu, Cătălin Ovidiu Popa, Marius Sorin Pustan, Nicolae Vlad Burnete

Estimation of Tribological Properties for Fe-Cu-Graphite-Ni-TiO2 Composites for Automotive Industry

Automotive industry is constantly developing due to the use of new technologies and materials that are allowing the finding of novel solutions in order to solve existing problems. This study is focused on using a mathematical predictor called Kriging for the tribological properties of iron-based composites so as to estimate their values. First, experimental data regarding the tribological properties was obtained for four Fe-Cu-graphite-Ni-TiO2 composite materials. Based on this data the appropriate Kriging estimator is established and the values for the friction coefficient and wear rate are predicted at intermediary TiO2 contents. Therefore, without using expensive equipment and time-consuming experimental tests such as trial and error method, the tribological properties of iron-based composite materials can be estimated. Based on the predicted values and using an optimization algorithm, the material with the optimal tribological behavior can be determined in order to be used in applications for the automotive industry, such as the manufacturing of brake pads.

Florina Maria Șerdean, Violeta Valentina Merie, Corina Julieta Bîrleanu, Cătălin Ovidiu Popa, Marius Sorin Pustan

A Comparative Study on the Comfort and Safety of the Seat Cover Fabrics

This paper deals with a comparative study of technical textiles designed for car seat covers (upholstery) in terms of comfort and safety. The work envisages a comparison traced between various materials, but not a comparison of the analysed properties to a specific, defined value. Aim of the research was to establish a correlation between automobile seat cover fabrics with different structure and some parameters responsible for comfort and safety. Another aspect of the study includes the comparison of different materials to synthetic leather.Seat fabrics samples analysed in this work are in form of woven, knitted fabric, and synthetic leather (PVC), actually target fabrics that tend to fulfil all the awaited prerequisite for seat covers. Thus, the test methods included measurements for air permeability, water vapour permeability abrasion resistance and flame retardancy.The present study tries to underline the physiologically comfort and safety characteristics offered by the seat covers made of various materials in comparison to synthetic leather. Further, it tends to establish the correlation between structure and features for a set of seat cover fabrics currently used by the automotive industry.The results highlight the importance of material’s type, fibrous composition and fabric structure of the seat covers upon their comfort and safety properties.

Ionel Barbu, Magdalena Simona Fogorasi, Mihaela Dochia, Monica Pustianu, Adina Bucevschi, Daniela Farima

Theoretical and Experimental Analysis for the Load Capacity of the Cone Tightening Assemblies

In this paper there are presented theoretical and experimental researches on the load capacity of a cone tightening assembly. Conical tightening assemblies are used in the automotive industry to assemble shaft pulley assemblies, such as assembling the pulley on the crankshaft or on the shaft of the current generator. It is necessary to test the theoretical and experimental maximum torque for different axial forces in order to ensure the proper operation of the designed assembly. The torque transmitted by the assembly is obtained in the first step by analysis with finite elements in ANSYS, and is necessary to be verified by experimental measurement. In the second step, the load capacity of this assembly, which is the dependence of the torque transmitted on the axial force of the assembly, is examined experimentally. For this purpose, an experimental test bench has been created to measure the axial force and torsion, by means of strain gauges transducers and a high performance measurement system. The results obtained by numerical simulation in ANSYS and by experimental research validate the prescribed specifications for designing these assemblies, commonly found in machine manufacturing.

Geonea Ionut, Dumitru Nicolae, Copilusi Cristian, Dumitru Ilie, Oana Otat, Tutunea Dragos

Optimized Prototyping for the Increasing of Performances of a Design Process

The level of production quality is established by the technological solutions adopted by designers during the design stage. In order to realize a product which responds to diverse customer requirements, the designers use a lot of methods and resources. One of them is the prototyping method. The designers use the prototype to propose, test and develop their theories and solutions. This paper presents a method to optimize the prototyping process for a product in order to increase the performances of the design process. The study was conducted at University of Pitești. Two design experiments were conducted for the same product. The first experiment used conventional methods of prototyping and the second one used the rapid prototyping. We followed the evolution of parameters: cost, duration, number of iterations needed to quantify the impact of the two methods. In order to represent and analyze the performance of studied experiments there were used instruments as: DSM (Design Structure Matrix), Manhattan distance, a graphical representation tool based on the model proposed by Pahl and Beitz.

Daniel-Constantin Anghel, Maria-Luiza Beșliu-Gherghescu, Nicolae-Doru Stănescu

On the Temperature and Chips Types in Milling of an Austenitic Stainless Steel

The cutting process of austenitic alloy is very difficult due to the low conductivity and tendency for built up edge. For this reason is very important to analyze the temperature and chips shape during cutting process. This paper try, based on some experimental results, to study the influence of cutting parameters on the temperature developed during the cutting process. For this, both infrared pyrometer and thermocouple are used to measure in the same time the temperature. Also the chips types is analyzed.

Nicolae Craciunoiu, Daniela Tarata, Cosmin Miritoiu, Emil Nicusor Patru, Dumitru Panduru

On the Cutting Tool and Workpiece Temperature in Turning of Titanium Parts Used in Automotive Industry

Although they have a high cost, titanium and its alloys have begun to be very used in automotive industry, due to the lightweight and high strength. As is known, an important role to increase the tool life and reduce the wear of cutting tool is the temperature during the cutting process. This paper presents the some researches on the cutting tool and workpiece temperature during the turning process of pure titanium.

Dumitru Panduru, Nicolae Craciunoiu, Emil Nicusor Patru, Marin Bica

Influence of Cutting Tool Diameter on Cutting Tool Temperature in Milling of Aluminum Alloys Used in Automotive Industry

The aluminum alloys are widely used in automotive industry being second-most used material in automobiles industry. Because many parts are made using aluminum alloys and the trend is to increase them, many researches try to analyze in their works the rolled products but also machining products. This paper presents, using the different technique, the variation of temperature values as function of aluminum alloy types and tool diameter, during milling process.

Emil Nicusor Patru, Nicolae Craciunoiu, Dumitru Panduru, Marin Bica

Powertrain and Propulsion

Frontmatter

Effect of Electrode Geometry on Flame Kernel Development in a DI SI Engine

The interest in lean burn combustion is related to the necessity of developing effective solutions for improving fuel economy and reducing exhaust emissions, in particular for new generation direct injection (DI) spark ignition (SI) engines. However, it is also consolidated that lean operation is associated with increased cycle-by-cycle variability. In this context, turbulent mixture motion can play a critical role, since burning rates are much lower than in stoichiometric engines. Turbulence levels are correlated to combustion chamber geometry and intake flow organization; however, it is still not clear how swirl and tumble affect the ignition phase and flame kernel inception in lean DISI engines. In particular, the effect of spark plug geometry on ignition has been minimally treated. It is exactly this aspect that constituted the starting point of this work, with an interest in flame kernel development and cyclic combustion variability. Experiments were performed on a gasoline fueled DISI engine by comparing three electrode geometries at fixed crankshaft rotational velocity and maximum brake torque spark timing, in stoichiometric and lean burn conditions. Specifically, standard J-plug, double electrode and surface discharge spark configurations were tested in an optically accessible single cylinder engine, by using UV-visible visualization and in-cylinder pressure analysis. Digital imaging at fixed delay from spark timing allowed the evaluation of cycle-by-cycle variations of the main morphological parameters of the flame front during the early combustion stages. Particular interest is devoted to the flame kernel development and its displacement with respect to the geometrical center of the combustion chamber.

Simona Silvia Merola, Adrian Irimescu

Influence of Dwell Time for Double Injection Strategies in a Wall Guided GDI Engine

Direct-injection (DI) in spark-ignition (SI) engines has been highlighted as an effective solution for improving engine performance. Since fuel is injected directly into the cylinder, a wide range of injection strategies can be applied. In this study, the aim was to improve air-fuel mixing by implementing a double-delivery strategy performed during the intake stroke, with an interest in the effect of dwell time (i.e. the duration between the two injections). To analyze the effects of this alternative control strategy, a homogeneous-charge-type gasoline DI engine with a side-mounted multi-hole-type injector was utilized. The timing of the second fuel delivery event was swept in a wide crank angle degree range in an attempt to reach the optimal balance between performance and emissions. In particular, the reduction of soot formation in the combustion chamber was considered an important target. Thermodynamic analysis of in–cylinder pressure data and exhaust measurements were correlated to chemiluminescence results from spark ignition to the late combustion phase, thanks to the optical accessibility through the piston crown, rendering the combustion chamber visible from below.

Adrian Irimescu, Simona Silvia Merola

Functional Analysis of a Gasoline Injection Engine

The paper realizes a comparative analysis of dynamics and fuel saving performances in different engine load and engine speed conditions. Also, it aims to identify factors that significantly influence engine performances. It aims to establish the correlation between functional parameters. There are stabilized mathematic models for engine’s functioning in dynamic regime by using system identification algorithm. Also, some static characteristics of engine operation at stationary modes are established. Values for appreciation criteria for the energy efficiency of the engine using experimental data have been defined and set. In order to solve the proposed problem experimental researches were carried out with a gasoline engine powered vehicle. Experimental data has been acquired and processed using a specialized tester to collect data from the onboard computer of the vehicle.

Barothi Laszlo, Sava Daniel, Darie Cătălin-Dumitru, Cucu Leonard-Iulian, Copae Ion

Drag Phenomena Within a Torque Converter Driven Automotive Transmission - A Turbulent Flow Approach

This paper tries to consider and analyze the effect of a torque converter influence over the coasting mode of a heavy military vehicle, considering the slip between the converter’s impeller-turbine blades. Since this interaction is an important source of drag within the transmission, when analyzing the dynamics of the coasting process it should be seriously taken into account. Testing an existent torque converter unit on a test bench is the best way to assess its internal drag, if the data provided by the manufacturer weren’t available. This paper aims at providing a procedure to reveal the transmission overall drag assuming the torque converter as being its main provider. The procedure roots over plenty of experimental research. Nevertheless, the induced friction within the transmission’s components has to be referred as an unloaded one. The tests determine the inertial moments of the driveline parts using the “falling weight” principle. Two approaches are available when comes about assessing the torque converter’s hydraulic inner drag, i.e. the laminar flow approach and the turbulent one. As the laminar approach was the topic of a previous evaluation, this paper goes for a mathematical model if turbulent flow was considered.

Marin Marinescu, Ion Lespezeanu, Radu Vilău, Constantin-Ovidiu Ilie, Octavian Alexa

Potential Performance Characteristics for Different Types of Tractors: Two-Wheel-Drive Tractor, Four-Wheel-Drive Tractors and Crawler Tractors

The paper addresses a very important criterion for the evaluation of the tractive and economical performances of agricultural tractors, namely the potential performance characteristics, which represents the drawbar power curve depending on the drawbar pull. At a large scale, this curve coincides with the tractive efficiency of the tractor taking account of the drawbar pull. We herein present the mathematical modelling of the potential performance characteristics which is particularized for three types of tractors: two-wheel-drive tractor, four-wheel-drive tractor and caterpillar tractors. The mathematical modeling has a high degree of generalization: the final mathematical functions comprise only dimensionless parameters. Related graphs are subsequently presented and the three types of tractors are comparatively analyzed taking into account the tractive and economical performances. Considering the potential performance characteristics, we put forward proposals for an accurate design of a tractor transmission when establishing the number and structure of gears.

Mircea Nastasoiu, Nicolae Ispas

An Experimental Research on Power Losses into an Automotive Manual Transmission

A significant part of the energy produced by vehicle engine is lost into the mechanical transmission. This phenomenon is still present at common drive train constructions used in automotive vehicles.Theoretical models were developed in order to evaluate the power losses into automotive transmissions, but none of them is capable to cover all transmissions configurations and structures, traffic or loading situations etc.The power losses into automotive transmissions depend on the specificity of each construction. Moreover, it is extremely difficult and delicate to identify and separate all the phenomena or causes of power loss and also, their influences during the vehicle use. The paper aims to present some of them, their effects and results, some observations based on experimental measurements of power losses into a certain passengers car transmission and also aims to identify some of those main influencing factors.In order to contribute, in the future, to better transmissions modeling, experimental researches were made. The results were obtained by testing an entire vehicle on a chassis dynamometer. This approach ensured a good similitude between the testing conditions and the ones from real world operation of motor vehicles drivetrains.

Adrian Budală, Adrian Şoica

Optimization of Cooling System for Internal Combustion Engines

In this paper, the authors tackle the problem of energetic optimization of the cooling system of internal combustion engines (heat exchanger, water pump, air ventilator, hydraulic transport installation and thermostat) by the adjustment of fluid flows and their economic correlation. The adjustments can be primary, secondary and combined, resulting different characteristics, emphasized by numeric application. The increase of economic efficiency Ɛec (indicator defined by authors), for imposed thermal efficiency Ɛt, leads to energetic savings due to the reduction of driving power and fuel consumption.

Radu Tarulescu, Stelian Tarulescu, Adrian Soica

Availability Analysis of Alternative Fuels for Compression Ignition Engine Combustion

Modeling of engine heat release from in-cylinder pressure is a common practice for characterizing engine combustion. Fuel property variation induces changes in engine performance, which can be categorized through heat release modeling. One under-utilized form includes an availability analysis that links changes in fuel properties to the amount of availability extracted as work or lost through inefficiencies. Here, a diagnostic heat release model is used to catalogue both the 1st and 2nd Law behavior of numerous alternative fuels. Conventional engine combustion using diesel, biodiesel, renewable jet fuel, and waste-plastic derived diesel are studied, alongside dual-fuel operation of compressed natural gas (with diesel) and synthesis gas (with biodiesel), allowing for the exploration of combustion with respect to changing fuel properties. In particular, more ideal fuel mixing is generally reflected directly in the 2nd Law efficiency. However, high viscosities largely result in a later availability addition that is not extracted as work. While this availability would be wasted at exhaust blowdown, deliberately increasing later temperatures may be useful if paired with exhaust heat recovery systems. Overall, the 2nd Law model presents these tradeoffs more clearly than a traditional 1st Law analysis; thus, its further use may be warranted in concert with advanced engine combustion modes.

Jonathan Mattson, Christopher Depcik

Usage of Electric Motors/Generators for Engines Supercharging in Order to Increase the Efficiency of Exhaust Gas Energy Recovery

According to UE regulations, starting with 2020, the amount of dioxide de carbon (CO2) will be limited to 95 g/km. Reducing the engine’s fuel consumption will lead to lower CO2 emissions. As presented in the paper, making greater use of exhaust gas energy to further compress the intake air can lead to a reduction in CO2 emissions compared to the classic supercharging solutions. In this regard, one solution is to drive the supercharger with a variable-speed electric motor. The paper presents in detail the electrical power required for powering the electric motor. The modern concept of supercharging which use the electric motors is emphasized. In addition, the paper identifies a solution to power the electric motor with electricity obtained from a process to recover the exhaust gas energy.

Cristian-Ioan Leahu, Sebastian Radu, Stelian Tarulescu, Radu Tarulescu

A Conventional Approach to Estimate NOx and Soot Emissions of a Diesel Engine Fueled with Diesel and Biodiesel Fuels

The present paper describes an analysis made with two methods for the emissions estimation of an engine, when using Diesel fuel and Biodiesel, based on mathematical interpolation and approximation functions. Results are validated against experimental data obtained on an instrumented test-bed comprising a tractor Diesel engine (UTB 240555 Brasov-type) and by simulations applying the AMESIM code simulation tool. Further studying activities corresponding to the use of the models applying split-injection strategies should highlight a reliable manner to decrease NOx emissions by preserving engines performances.

Bogdan Radu, Radu Chiriac, Alexandru Racovitza

Effects of Re-designing of Two-Stroke Engine Fuelled with Gasoline - Ethanol Blend on GHG and Pollutant Emissions

The paper presents the research designed to develop a spark-ignition engine, two-stroke engine fuelled with ethanol and ethanol-gasoline blends. The test engine chosen was a small single cylinder, two strokes provided with a carburetor. The results of experimental research data obtained on this version were used as a baseline for the next phase of the research. In order to obtain the test engine configuration, the engine was modified, as follows: the compression ratio was increased from 8.0:1 to 9:1 to improve the engine efficiency; the carburetor was replaced by a direct fuel injection system in order to control precisely the fuel- mass per cycle, taking into account the measured air-mass intake. The cylinder’s processes were simulated on a virtual model. The experimental research works were focused on determining the parameters which control the combustion process of two-stroke engine to obtain the best energetic and ecologic parameters. The fuel consumption data obtained during the tests are used to determine the emissions of GNG on basis of the emissions’ factors. The main conclusion of the results was the GHG emissions using “well-to-wheels” method. The pollutants were measured for all operating test points and were compared, taking into account the initial engine configuration.

Corneliu Cofaru, Nicolae Ispas

Kinematic Analysis of a Variable Compression Ratio Mechanism

In our previous papers [13, 14] we presented a variable compression mechanism. In this paper we study the kinematic analysis of this mechanism. Two cases are considered: there is no motion for the control lever, and the second one is characterized by the existence of a known motion for one edge of the control lever. The kinematic analysis is performed firstly in a classical way by determining the positions of some characteristic geometric parameters and by derivation of these parameters with respect to time. The second way is by use of the multibody approach to determine the matrix of constraints for the mechanism. In the last situation we can not determine all the linear and angular velocities for the mechanism. Usually, a number of new equations (this number is equal to the degree of mobility of the mechanism) must be added in order to determine all kinematic parameters. A numerical example concludes this study.

Bogdan Mănescu, Nicolae-Doru Stănescu

Issues Concerning the Determination of the Correspondence Between Low Pressure Distillation and Gas Chromatography Analysis of Biodiesel. Preliminary Results

Increased environmental awareness and depletion of fossil petroleum resources are driving the automotive industry to seek out and use alternative fuels. The most eminent alternative fuels for replacing fossil fuels in internal combustion engines are biofuels (biodiesel and bioethanol).Transportation fuels consist of a large number of species that belong to different families of organic compounds with various volatility characteristics. Thus, the usage of detailed evaporation models is restricted by these species and demands an alternative approach.Volatility is defined as the tendency of a material to change from a liquid state to gaseous state. Proper volatility of fuels is critical to the operation of internal combustion engines with respect to both performance and emissions. Thus, more detailed analysis of fuel volatility properties is a necessity.An alternative to physical distillation or true boiling point distillation is simulated distillation by Gas Chromatography. This method is very rapid, reproducible, easily automated and can better define initial and final boiling points.The objective of this paper is twofold: first, to present our method of finding the distillation curve for a type of biodiesel by reduced pressure distillation; and secondly, to determine a simulated distillation by Gas Chromatography and find the relationship between the boiling points of the normal compounds and determined retention or elution time.

Rodica Niculescu, Mihaela Nastase, Adrian Clenci, Victor Iorga-Siman, Catalin Zaharia

Combustion Analysis for Single Cylinder Engine Running on Various Types of Diesel

In this paper, the authors seek to identify the major differences between the combustion of several market available winter grade diesel fuels to determine the best option with respect to the combustion parameters (ignition delay, peak pressure, rate of heat release, peak cylinder temperature etc.) and overall efficiency of the process. To do this, the pressure traces and pollutant emissions are recorded at constant speed and various loads. A correct interpretation of the pressure trace is essential for understanding the phenomenon inside the engine. The results showed that there is a difference of approximately 13.8% in terms of peak engine power, 13.7% in terms of torque, 68.1% in terms of CO, 14.1% in terms of CO2, 4.9% in terms of NOx and 27.8% in terms of HC. Based on the obtained results, one can identify the optimum solution in terms of available diesel fuel.

Burnete Nicolae Vlad, Șerdean Florina, Burnete Nicolae, Moldovanu Dan

Constructive Optimization of a Mechanism of Variable Valve Control

The mechanisms of variable valve control are frequently used on thermal engines which equip usual automobiles. In our paper we present such a solution consisting in a cam in rotational motion, a triad and a follower in plane-parallel motion. For this solution we perform the synthesis of cam and the kinematic analysis of the mechanism. The used methods are classical analytical ones of analysis and synthesis of cam, as well as CAD methods. The synthesis of cam by a CAD method assumes: the positioning of the raw material that materializes the cam, construction with solids of the follower as well as its positioning, extraction of the follower from the raw material, rotation by one degree of the obtained solid and the repeating of the procedure for the new angle. These operations are realized with an AutoLisp function which is not influenced by the complexity of the mechanism. The principle of the method of positional analysis by a CAD method consists in the modeling of the cam and follower with solids, variation of the rotational angle of the cam with the aid of an AutoLisp function until the follower is in contact with the cam and, finally, determination of the displacement of the valve of mechanism. In the end of the paper we present the constructive optimization of the cam mechanism by heuristic methods. The used algorithm has four steps, resulting finally the shape of the follower and the optimized cam.

Claudia-Mari Popa, Dinel Popa, Nicolae-Doru Stănescu

Butanol Effects on the Fuelled Diesel Engine Operation with Preheated Diesel Fuel-Animal Fat Blends

The main objective of the paper is the determination of energetic and pollution performance of a diesel engine fueled with three different fuels: diesel fuel, diesel fuel-animal fat blends and diesel fuel-animal fat–butanol blends. At the rise of animal fat percent in mixture with diesel fuel, the flow resistance of blend increases, because the fuel viscosity increase, the fuel atomization is worsened. Through butanol addition, the viscosity of the blend decreases and the engine operation is improved. The engine performance and the pollutant emissions level at the use of 5 and 10% animal fat in blends with diesel fuel, with or without addition of 5% butanol in content, are presented comparative to diesel fuelling. The indicated mean effective pressure, maximum pressure, maximum pressure rise rate, maximum rate of heat release, indicated specific energetic consumption, HC, NOx and smoke emissions level of the diesel engine fuelled with butanol-animal fat-diesel fuel blends are evaluated and analyzed.

Cernat Alexandru, Pana Constantin, Negurescu Niculae, Nutu Cristian, Nicolici Adrian

LPG as Alternative Fuel for Clean Automotive Diesel Engines

The objective of the paper is directly related with a worldwide reality knowing that many European capital cities, such as Paris, Madrid and Athens, want to be free from automotives equipped with diesel engine by year 2020 because of pollution issues, since the C40 Mayors Summit 2016 takes place. According to the report on the Future Transport Fuels of European Commission for the year of 2050 regarding the Road transport, the use of synthetic fuels or paraffinic, methane or LPG becomes a necessity. The objective of the paper is to design and develop a Liquid Petroleum Gas (LPG) fuelling system for automotive modern diesel engine in order to assure the improving of pollution performance. The effects of LPG use at a 1.5 DCI automotive diesel engine of Dacia Logan MCV van at the regime of 40% engine load and 3900 rev/min are presented. The dual fuelled engine performance, in terms of pollutant emissions level and brake specific energy consumption, or in-cylinder pressure parameters are analyzed and compared with diesel fuel operation. By the analysis of the experimental investigation results the maximum LPG cyclic dose can be established in order obtain the highest engine performance at dual fuelling.

Nemoianu Liviu, Pana Constantin, Negurescu Niculae, Cernat Alexandru, Fuiorescu Dinu, Nutu Cristian

LPG—An Alternative Solution to Fuel a Car Diesel Engine

The objective of the paper is to improve the diesel engine operation by decreasing the brake energetic specific consumption, the cyclic variability and pollutant emissions. This goal can be achieved fuelling the engine with liquefied petroleum gas (LPG). A good correlation between the investigated regimens and the engine adjustments must be realised in order to limit the maximum pressure and smoke level, knock and rough engine functioning. A particular objective of this paper is to reduce the nitrogen oxides emission, which represents an important problem for a diesel engine. The correlation between the LPG quantity and the working regimen allows obtaining an improve in the functioning of the engine. In this way, by fuelling the engine with LPG is assured a low cyclic variability for relatively high substitute ratios. This paper also presents a nitrogen monoxide formation model for the case of LPG fuelling. To fuel the engine with LPG was utilised the diesel-gas method. This method can be also applied for engines which are already in service and consist in gaseous LPG injection into the intake manifold of the engine. Using the diesel-gas method, in the intake manifold of the engine is injected LPG in gaseous aggregation state and the air-LPG homogeneous mixture is ignited by the flame appeared in the diesel fuel sprays. The investigated regimen was 55% engine load and 3500 rpm.

Nutu Nikolaos Cristian, Pana Constantin, Negurescu Niculae, Cernat Alexandru, Dinu Fuiorescu, Nemoianu Liviu

Modeling the Torque Oscillations During Gear Shifts on Automated Manual Transmission

In recent years the market share of automatic gearboxes saw a continous growth and recent studies suggests that this growth rate will continue. For low cost and entry level range of vehicles, the usual choice is the automated manual transmission. The main disadvantage of the automated manual transmission compared to other automatic gearboxes is the low performance during gear shifts.This paper contains a model of a vehicle equipped with an automated manual gearbox with focus on the gear change. The objective of this paper is to simulate the torque oscillations during gear change and reduce them in order to increase the comfort for the passengers.

Ștefan Saragea, Ioan Mircea Oprean, Gabriel Badea, Gheorghe Frățilă

The Study of the Energetic Performance in Test Cycles Considering a Variable Powertrain Thermal Regime

The transmission is one of the key subsystems that influence the fuel consumption of the modern passenger cars. This is induced by the transmission efficiency and the engine operating points that result from engine-transmission-vehicle combination on a given test cycle. This paper aims to investigate the global performances of a modern transmission in different test cycles including the newly introduced WLTC (Worldwide Harmonized Light Vehicles Test Cycle) considering a variable powertrain thermal regime.The study is done using a complex model developed in a performant simulation environment. In order to compare the performances in different test cycles, one needs to determine specific parameters such as: vehicle speed fluctuation (VSF), overall transmission efficiency, fuel consumption ratio (FCR). The simulation results are compared against those obtained at constant thermal regime, the test cycles are compared using a relative parameter (FCR) and the correlation between FCR and VSF is analyzed.

Cristian Rențea, Mircea Oprean, Marius Bățăuș, Gheorghe Frățilă

Thermodynamic Study of Airflow Through the Spark Ignition Engine Intake Manifold

Recent studies show significant differences in fuel consumption and exhaust emissions depending on the temperature of the intake air. We can say that the fuel consumption is improved with the decrease of air intake temperature regardless of engine speed. Because of the position in the engine compartment the intake is highly expose to thermal radiations from the cooling radiator, exhaust pipe and engine itself which is a disadvantage, the intake air it heated and the result is a lower density, thus containing less oxygen per volume unit than cold air. The purpose of the study is to obtain the data needed to thermally optimize the intake manifold. Based on the data about the shape and geometric dimensions of the intake manifold, the 3D model is generated. Temperature measurements are made at different points of the intake manifold and at various engine operating modes. Experimental data is used to generate the numerical model of airflow simulation through the intake manifold. The results obtained will highlight the air heater mode depending on the material and the position in the engine compartment of the intake manifold.

Birtok-Băneasă Corneliu, Rațiu Sorin, Cioată Vasile, Budiul-Berghian Adina

A Pneumatic Propulsion System for Urban Cars

Compressed air vehicles can be an alternative for new, low polluting emissions, urban cars. This paper presents a new innovative concept of a pneumatic motor propulsion system that aims to improve the efficiency of such systems. The advantages and the disadvantages of the proposed propulsion system are taking into consideration and some application have been analyzed.

Tudor Mitran, Catalin Chioreanu, George Dragomir, David Fagadar

Dynamic Models for Analyzing a Self-propelled Vehicle for People with Locomotor Disabilities

In this paper there was made a virtual prototyping of a vehicle for servicing people with locomotor disabilities. This vehicle has as special components two differential transmissions that allow relatively easy optimization of the vehicle’s dynamic behavior. In addition to kinematic performance, this vehicle has a high degree of maneuverability as an important feature. Mathematical models for dynamic vehicle analysis are developed. Virtual prototyping involved designing the component parts that compose the component subassemblies. The main subassemblies are bevel gear differential transmissions, spur gear transmissions, worm gear drives from the traction and steering systems, including the shafts and housings of these subassemblies, the frame, as well as the propulsion train, all of those components are then assembled. The virtual prototype made in Solid Works is used to dynamically simulate in ADAMS of the assembly when running on a required trajectory. This vehicle is completed as an experimental model, being in the conception and implementation phase of the propulsion and steering control system.

Nicolae Dumitru, Ionut Geonea, Cristian Copilusi, Sorin Dumitru, Oana Otat

On the Stability of the Vehicle’s Cornering Motion

The paper goal is to present a theoretical and experimental study on the dynamics of the vehicle in the turn, at the adhesion limit. Starting from the simplified model of the vehicle in an accelerated motion (bicycle model) on the curved road are obtained the equations which are governing this motion, for the traction 4 × 2 and 4 × 4 cases. The experimental determinations were performed on three categories of cars with suitable testing equipment which recorded several important parameters of this complex vehicle motion.

Bogdan N. Nicolescu, Tiberiu Macarie

Study of Brake System Parameters for Commercial Vehicles

In the broadest sense, the braking system must be able to reduce the travel speed to a desired speed or to stop under any circumstances. The efficiency and performance of the entire braking process depend on a number of factors such as: the construction variant, the friction temperature, the variation of the friction coefficient with the force of thrust and temperature, the materials, the braking squeal, the wear and the particles resulting from the process. This paper is a review of brake parameters and an analysis of the main problems related to the current braking systems.

Popa Mădălin-Florin, Burnete Nicolae-Vlad

Experimental Research on a Diesel Engine

The main purpose of this paper is to present the comparative diesel engine analysis of dynamical and energy efficiency performances, in different functioning situations. Other purpose of the paper is to establish engine static characteristics for stationary regime. It also establishes the mathematical models for engine functioning in stationary regime and dynamic drive.This issue will be solved using experimental researches on a powerful diesel engine, installed to the testing stand equipped with fitted sensors for functional parameters. The research data were captured, stored and processed.

Nicolau Marin, Pântece Constantin-Iulian, Cucu Leonard-Iulian, Dorobanțu Gabriel-Ionuț, Copae Ion

Energy Based Slider-Crank Mathematical Model

The slider-crank mechanism is frequently applied in various applications across mechanical devices. The main utility of the mechanism is for conversion of thermodynamic energy to mechanical work and vice-versa. This case is commonly encountered in heat engines, compressors and pumps. The mathematical model that is used to design and investigate the behavior of the mechanism is ideal and it takes the angular velocity of the crank as input. The model is mainly used to determine the dynamic loads that act on the mechanism relative to time and also to determine the slider position relative to crank angle. In this paper an alternative mathematical model is proposed. This model is the outcome of an energetic analysis of the mechanism starting from the assumption that the kinematic parameters of the mechanism are given by the total amount of kinetic energy that is stored at that moment in the system.

Doru Groza, Ioan Călin Roșca, Gheorghe Alexandru Radu

Road Safety, Traffic Control and Transportation Engineering

Frontmatter

Determination of Some Vehicle Dynamic Performances Using the Dynamometric Roller Chassis

We can use a common definition which says that when a force is applied to a mechanical system, it will typically reach steady state after going through a few transient behaviors. The difference in performance between a stabilized and a transient mechanical system may be substantial. Loss of power during vehicle acceleration may be determined with a roller dynamometer. In this paper we determine the power loss in the car transmission as well as the power loss taking rolling resistance into consideration, in the transient acceleration mode, up to the maximum speed of the vehicle. We also highlight the speed performance values in comparison with the values given by the manufacturer with a view to ensuring the accuracy of transmission loss results.

Soica Adrian, Budala Adrian, Monescu Vlad

Capacity and Traffic Performance Depending on Intersections Design

Intersections are components of an urban road transportation system and maintaining these control systems at their optimal performance for different demand conditions has been the primary concern of the traffic engineers. Roundabouts are a very popular type of road intersections because they have a number of advantages, but if some geometrical and dynamic parameters are inadequate, capacity and traffic performance are affected. The main objective of the paper is to analyze an intersection and propose several scenarios in order to evaluate the quality of transportation performance. The solutions can solve some delays and traffic safety problems. For this study an intersection from Cernavodă city was chosen. This is a roundabout situated at the city’s entrance and has several accessibility and safety problems. To analyze the actual situation, intersection’s traffic flow, geometric and functional parameters were collected. For traffic simulation and modelling of the analyzed intersection, the SYNCHRO plus SIMTRAFFIC 9 Road Traffic Modeling and Simulation Program was used which is a typical application based on the theories of traffic engineering.

Manea Laurențiu, Manea Adriana, Țârulescu Stelian, Florea Daniela

Considerations on Using the Crash Pulse in the Vehicle-Vehicle Collision Assessment

The crash pulse in a vehicle-vehicle collision represents the variation of acceleration over time, from the moment of impact until the moment of zero velocity, or separation of the vehicles. The paper presents some methods and practices for the collection, retrieval, archival, and analysis of crash data, from crash tests and from real road events. The metrics used for crash evaluation, derived from the recorded crash pulse, include: maximum value of moving average acceleration, delta-v (the change in velocity), displacement, energy density, power rate density. Crash pulse based analysis can simplify the integration of crashworthiness into vehicle design. Data sources used by authors were mainly the crash tests performed at Transilvania University.

Dragoș Sorin Dima, Dinu Covaciu, Anghel Chiru

Critical Evaluation of the Pedestrian Walking Distances on the Congested Urban Networks

The continuous increase in traffic demand during the last years has generated changes in urban road networks design. Implementation of roundabouts is a general trend in the large Romanian cities. Thus, even in dense built areas, the signalized intersections have been turned into multiple lanes roundabouts, without taking into account, besides drivers, other important groups of road users: pedestrians, cyclists, people with disabilities, etc. - or the requirements for implementation of modern strategies regarding priority for public transport. The paper proposes a critical analysis of pedestrian movements in the road network when, in congested areas of a medium sized city where are grouped educational and public institutions, retail centers, touristic and residential buildings, were implemented multiple roundabout intersections. Modeling of the traffic flows using the computer programs, allows obtaining some performance indicators taking in account the influence of pedestrians’ flows, and helps establishing the network efficiency, before and after the implementation of the proposed solutions for increase of sustainable urban mobility. Data required for traffic flows modeling, that should correctly describe the real geometric, traffic and signaling conditions, their complexity, as well as the impossibility to analyze the network at a global level, are limitations of the study.

Daniela Florea, Dinu Covaciu, Janos Timar, Stelian Ţârulescu

Experimental Research in Case of Car to Pedestrian Collision

Pedestrians are some of the most vulnerable road users in traffic accidents. Therefore, in the context of the worldwide development of urbanization and motorization, vehicle-pedestrian collisions and, in particular, pedestrian injuries resulting from these accidents continue to represent a major problem in the public health sector around the world.The main objective of this paper is to study the kinematics and dynamics of pedestrian impact, in order to highlight some features of the reconstruction of road accidents involving pedestrians.In this study, the data used was obtained from crash tests that has been performed using a dummy fitted with a triaxial accelerometer in the head. These data has been used to assess the injury criteria of the pedestrian.

Liviu Petrescu, Alexandru Petrescu

The Relevance of Public Questionnaires on the Development of Measures to Increase Sustainable Urban Mobility

According to European Commission documents, road transport is vital for economic development, for commercial and social integration, allowing free movement of people and goods at local and regional level. Road transport plays an important role in the everyday life of citizens as a means allowing easy access to services and social activities [1].Forecasts show that road transport will remain the most important means of travel for travellers.The Urban Mobility Plan is a way to address issues related to the transport of people and goods more efficiently, whether public or private. Such a plan aims to create an urban transport system that provides easier access for people to workplaces and service providers; decreasing travel times and transport costs; reducing pollution and energy consumption; as well as improving safety in traffic [6].The main purpose of the study was to evaluate how the organization of public transport meets the current travel needs of people in the administrative territory of the Alba Iulia and Bistrita municipalities, as well as assessing the restrictions and opportunities in promoting green transport. In this context, two questionnaires were developed in order to investigate the demand for population mobility in the mentioned cities. These questionnaires were used in proposing urban mobility plans.

Georgiana Muresan, Nicolae Filip

Traffic Modeling in Urban Congested Areas

The paper aims to identify solutions for traffic safety enhancement in an urban area where major changes in traffic flow intensity and pattern will occur. The changes of the study area pattern will be caused, on the one hand, by the development of new residential and office areas and, on the other hand, by the opening of a new road overpass linking the inner urban area with an outside area where peri- and regional traffic flow are concentrated. The assessment of the traffic systematization solutions under these new conditions is based on a simulation model developed with the AIMSUN software. The study area is located in Bucharest, around the zone of University Politehnica of Bucharest Campus. The main difficulty of the model consists in the prediction of the exogenous traffic data of the study area. The simulation model is applied for one proposed scenario considering the increase of the traffic flow intensities. A set of measures for traffic systematization is assessed and compared based on flow features (speed, frequency and time of stops, external effects limitations).

Cristina Oprea, Mircea Roşca, Şerban Stere, Sergiu Olteanu

Research Regarding on Choosing Optimal Traffic Organization Using Ranking Criteria

In the present research the main purpose is to analyze and choose the optimal traffic organization scenario by assigning a number of points in relation to the simulation traffic results. This research aims to quantify the relevance of the correlation between the delay and the intersection capacity utilization index resulting from the simulations by choosing the best traffic organization between a signaled intersection and a roundabout. The indicators’ ranking takes into account the significance of each in terms of traffic. Thus, it is considered a ranking for the intersection capacity utilization index and a ranking for the values of the delays. The case study proposes to conduct an analysis in an area in the city of Cluj-Napoca. As results of the developed study, we propose alternative traffic organization in order to reduce the maximum queue at the intersection.

C. Gheorghe, N. Filip

On the Management of Activity of Technical Control of Motorvehicles

This study is focused on the investigation of the activity of technical control of motorvehicles with respect to the implementation and adaptation of EU regulations. Following current status and analysis was performed and some proposals for the improvement of the management system will be presented.

Marian Burcea, Ion Tabacu

Explanatory Models of the Weather Factors’ Influence on Road Traffic Accidents Produced in Romania in Different Road’s Features

This paper aims at identifying the best explicative models of the road adherence, lighting conditions and weather factors’ influence on road accidents occurred on various road features. The road accidents that caused victims between 01.01.2014–21.12.2016 in Romania have been analyzed and grouped on a monthly basis. The total number of road traffic accidents that caused injuries, accidents that occurred in alignments, in curves and intersections have been analyzed as dependent variables.Twenty four different features of lighting and weather conditions and also of road adherence have been taken into consideration as explanatory variables. Multiple linear regressions have been applied and their global significances have been tested by using Fisher test. The individual meanings of the explanatory variables coefficients have also been tested, in order to choose the best explained model.The wet roads and those covered by snow, cloudy sky and rains are the most present in these explanatory models. The slippery roadways, no street lighting and the rains explain the accidents produced in curves.The cloudy sky, the functional and broken street lighting and the normal weather conditions explain the road accidents in a proportion of 98,90%.

Alin Drosu, Corneliu Cofaru

The Monitoring of the Submarine Effect in Frontal Collisions, at Different Impact Speeds and for the Driver’s Out of Position Instances

Within the present study we put forward a novel method to monitor and assess the occurrence of the submarine effect in frontal collisions at different impact speeds. In this respect, we designed by means of the LS-Dyna software platform a complex model consisting of the dummy, the seat, the steering wheel, the dashboard and safety systems, an airbag and a seat belt.The cases considered focused on impact speeds of 30 km/h, 40 km/h, 50 km/h and 60 km/h. The Hybrid III female dummy was placed on the driver’s seat, first in a normal position, and then, in ten out of position instances, for which the impact speed was defined.To monitor the occurrence of the submarine effect, the relative displacement between the pelvis center and the seat assembly was analyzed and registered.Accordingly, we analyzed all 44 cases considered, and at different speeds and critical positions we tracked the effects upon the dummy, due to its sliding under the seatbelt.We set out to test and validate a novel method, applied to assess the occurrence and the consequences of the submarine phenomenon, based on the virtual prototyping of the seat – dummy- safety systems assembly and the analysis of the finite element.

Oana Victoria Otat, Victor Otat, Dragos Tutunea, Ionut Geonea, Gabriel Marinescu

Influences of the Suspensions Characteristics on the Vehicle Stability

The main objective of the paper is to track the influence of the suspension system on the stability for a vehicle on a particular route using a simulation program. The suspension of the vehicle is designed to attenuate the dynamic loads that are transmitted from the road, to impart the desired character to the oscillations. The oscillations that occur when the vehicle passes over the irregularities of the road influences the technical qualities of its operation, first of all its smoothness, traction qualities, stability, maneuverability and durability. The role of the suspension is to provide the vehicle a maximum lateral acceleration on the track, which is why it must ensure the maximum grip at the wheels to the rolling surface. For this, the up and down vertical movement of the vehicle wheels will be damped such as to ensure an optimum constant contact with the road surface. The time at which the wheel oscillation (induced by a shock received from the tread) is damped must be as short as possible but not affect the grip developed by the wheel. In terms of the working methodology to achieve the purpose of the work, we rely to the simulation software (IPG CarMaker), which predefines the driver behavior, initialize the data for the vehicle suspensions predefined in the simulation program. According to the working methodology, the results obtained will be analyzed and interpreted graphically, surprisingly comparing the various situations considered in the study, with emphasizing the influence of suspension system on the vehicle body.

Nicolae Cordoş, Adrian Todoruţ

Evaluation of the Vehicle Sideslip Angle According to Different Road Conditions

The sideslip angle is the angle between the median plane of a steering wheel subjected to transverse effort (in the case of a cornering or side winding) and the actual travel direction of the vehicle. The sideslip angle always increases with increasing the lateral force at the wheel. A lateral force generates a slip angle, and a sliding angle generates a lateral force. The steering angle generates a sliding angle on the contact patch between the tire and the tread and at the same time creates a lateral force. The sideslip angle is positive if the tire is rotating around the vertical axis to be aligned with the velocity vector (the direction of the vehicle speed). A positive slip angle will generate a negative lateral force. To achieve the purpose of the paper, a simulation program (IPG Carmaker) is used, which defines the driver’s behavior, initializes the data for the nature and condition of the running track, the characteristics of the vehicle under study, and chooses a route were the vehicle is running. According to the working methodology, the results obtained will be analyzed and interpreted graphically, surprisingly comparing the various situations considered in the study, with emphasizing the influence of the road conditions and the lateral force on the sideslip angle.

Adrian Todoruţ, Nicolae Cordoş

The Overlap Influence in Case of a Car-to-Pedestrian Accident

The main objective of the paper is to determine how the overlap between the pedestrian and the vehicle influence the head injury severity in case of an accident. In order to solve this objective, two full scale crash-tests were performed, using two vehicles and a crash-test dummy. In the dummy’s head, a tri-axial accelerometer was mounted in order to measure head accelerations, and by calculating HIC (Head Injury Criteria), the head injury can be assess.

Tolea Bogdan, Radu Alexandru Ionut, Beles Horia

Analysis of Car-Cyclist Accidents Occurring at Relative Medium and High Vehicle Speed

The road accident-involving cyclist is frequent in Romania. Hungary, Romania and Croatia had the highest cyclist fatality rates per million population in the EU in 2015. Estonia, Luxembourg and Greece had the lowest cyclist fatality rates per million population in the EU. The mortality rate of a cyclist accident is significantly higher than for other accidents. Thus, cyclist accident is one of the most accidents of traffic accidents and, therefore, cyclists are one of the most vulnerable road users. Often accidents involving cyclists happen on roads outside urban areas. Many of these bicycle car collisions occur at intersections, with the bicycle running perpendicular to the forward direction of the vehicle. These types of cyclist impacts are characterized by collision speeds above 55 km/h, and are often fatal for the cyclists involved. The main purpose of this paper is to analyze the conditions in which such accidents occur. The theoretical reconstruction of the road traffic event in order to obtain results as close of the real event is another goal of this paper.

Nicolae Ispas, Mircea Nastasoiu, Radu Iulian Negrila

A Comparative Analysis of the Road Noise Immission Models

Road noise pollution is one of the most topical environmental issues for local authorities, under the circumstances of increasingly demanding legislation in this area. In this context, the use of road noise models is of particular importance - on the one hand, in the design of new road infrastructures - in order to assess the acoustic impact and avoid further passive noise protection measures that can be very costly, and, on the other hand, for the existing road networks, to minimize noise measurement campaigns only to the volume required to calibrate the model. After a brief presentation of the most commonly used road noise prediction models, a series of simulations were carried out using the Dutch 2002 software based on the British CoRTN model for different values of traffic characteristics on the road artery in front of Building T of the University of Pitesti. Immediate noise measurement at the level of the building, under the same road traffic conditions as in the simulation, confirms the veracity of the results obtained by means of simulation. Finally, a complex model is proposed for predicting the immission of road noise on the basis of road traffic and noise propagation characteristics, where, in the case of long and narrow road arteries, when traffic simulation is carried out at a macro level, the complex model is operable on the basis of already existing noise emission models.

Andrei-Alexandru Boroiu, Elena Neagu, Alexandru Boroiu, Sebastian Parlac

The Significance and Effect of the Traffic System Signaling to the Environment, Present and Future Traffic

The development of automotive technologies brings new features such as the emergence of autonomous vehicles and an advanced infrastructure, but is a big challenge for the professionals. In this paper we present the currently used signs on the different road sections. We describe the significance of signaling systems for the present and future traffic, especially from the point of view road safety and environment. We analyzed the used traffic signs recognition systems how them can identify the signals in the traffic. Particular emphasis is placed on the benefits, the importance and the problems that arise in recognizing systems. We will propose their development opportunities, and these will affect the pre-emergence period of fully autonomous vehicles when the vehicles are on lower autonomy level but at the same time the higher autonomy level vehicles are appear in the traffic. It has difficulties with the recognition systems and the emergence of autonomous vehicles. There may be problems with systems in different signaling systems. There are some other problems what need to find solution for example is the legal rules to the autonomous vehicles and different country has different looking traffic signs what is hard to recognize to the systems.

Henrietta Lengyel, Zsolt Szalay

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