Proceedings of the FISITA 2012 World Automotive Congress

Cylinder deactivation has been proposed so far for improved part load operation of large gasoline engines. In all this application, the cylinder deactivation has been achieved keeping the intake and exhaust valves closed for a particular cylinder, with pistons still following their strokes. The paper presents a new mechanism between the piston and the crankshaft to enable selective deactivation of pistons, therefore decoupling the motion of the piston from the rotation of the crankshaft. The reduced friction mean effective pressure of the new technology enables the use of piston deactivation in large engines not necessarily throttle controlled but also controlled by quantity of fuel injected. Results of performance simulations are proposed for V8 gasoline and Diesel engines producing significant savings during light operation, larger for the gasoline but still substantial for the Diesel.

Improvements of vehicle fuel economy may be achieved by the introduction of advanced internal combustion engines (ICE) improving the fuel conversion efficiency of the engine and of advanced power trains (PWT) reducing the amount of fuel energy needed to power the vehicle. The paper presents a novel design of a variable compression ratio advanced spark ignition engine that also permits an expansion ratio that may differ from the compression ratio hence generating an Atkinson cycle effect. The stroke ratio and the ratio of maximum to minimum in-cylinder volumes may change with load and speed to provide the best fuel conversion efficiency. The variable ratio of maximum to minimum in-cylinder volumes also improves the full load torque output of the engine. The paper also presents an evolved mechanical kinetic energy recovery system delivering better round trip efficiencies with a design tailored to store a smaller quantity of energy over a reduced time frame with a non-driveline configuration. Simulations show an improvement of full load torque output and fuel conversion efficiency. Brake specific fuel consumption maps are computed for a gasoline engine 2 litres, in-line four, turbocharged and directly fuel injected showings significant fuel savings during light and medium loads operation. Results of vehicle driving cycle simulations are presented for a full size car equipped with the 2 L turbo GDI engine and a compact car with a downsized 1 L turbo GDI engine. These results show dramatic improvements of fuel economies for similar to Diesel fuel energy usage and CO

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production. The turbo GDI engines with the alternative crank trains offer better than hybrids fuel economies if the vehicles are also equipped with the novel mechanical kinetic energy recovery system (KERS) recovering the braking energy to reduce the thermal energy supply in the following acceleration of a driving cycle.

Optical Visualization system was applied to record images of the processes of spray, mixed gas formation and combustion in a homogenous GDI engine. Fuel spray was optimized by visual analysis of the images, thus improved the quality of mixed gas and combustion in the cylinder, it can provide the reference for injector selection and EMS calibration.

Over the last few years, a new and cost-effective pneumatic regenerative engine braking (RegenEBD) concept has been researched and developed in order to improve the fuel economy of inner city buses. The RegenEBD concept is realised by swapping a standard engine braking device from the exhaust side to the intake side and implementing a proprietary one-way intake design. The engine is operated as a compressor during the vehicle deceleration through the action of RegenEBD so that the vehicle’s kinetic energy can be converted into pneumatic energy in the form of compressed air. Regenerative stop–start can then be realised through the use of a standard air starter motor. In this paper, the prototype RegenEBD engine and bus are first presented. This is followed by a discussion on the engine testing results and preliminary bus driving tests. Experimental results show that the fuel economy can be improved by 5–10 % for inner city buses, and there is potential for improved vehicle performance through instant boost by the regeneratively produced compressed air.

Controlled Auto Ignition (CAI), also known as Homogeneous Charge Compression Ignition (HCCI), is one of the most promising combustion technologies to reduce the fuel consumption and NOx emissions. Currently, CAI combustion is constrained at part load operation conditions because of misfire at low load and knocking combustion at high load, and the lack of effective means to control the combustion process. Extending its operating range including high load boundary towards full load and low load boundary towards idle in order to allow the CAI engine to meet the demand of whole vehicle driving cycles, has become one of the key issues facing the industrialisation of CAI/HCCI technology. Furthermore, this combustion mode should be compatible to different fuels, and can switch back to conventional spark ignition operation when necessary. In this paper, the CAI operation is demonstrated on a 2-stroke gasoline direct injection (GDI) engine equipped with a poppet valve train. The results shown that the CAI combustion can be readily achieved in the 2-stroke cycle of a poppet valve engine and the range of CAI combustion can be significantly extended compared to the 4-stroke cycle operation. In addition, the effects of ethanol concentration on 2-stroke CAI operational range, combustion process, emissions and efficiencies are studied and presented.

Gasoline engine downsizing has been demonstrated to give significant reductions in vehicle fuel consumption and CO

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emission levels by effectively moving the engine operating points for any given drive cycle to a more efficient region of the BSFC map. The limit to which downsizing can offer advantages to fuel efficiency therefore comes when the average engine operating points are centred around the minimum BSFC region. To take downsizing further, a number of complementary technologies are being explored with the aim of increasing overall efficiency and extending the operating region of optimum efficiency. Additional benefits can be derived from secondary effects when technologies are combined. This paper summarises such complementary technologies and discusses how they can be used in practice to further optimise gasoline engine efficiency.

Homogenous Charge Compression Ignition (HCCI) technology shows a great fuel economy potential for gasoline engine. In the project, a 4-cylinder 1.5 L PFI gasoline engine with HCCI and SI combustion mode was developed based on optimized heat management. The exhaust gas energy and coolant energy are used for heating intake air to suitable temperature as soon as possible. The exhaust turbocharger and EGR are used to expand HCCI operating range. Also cylinder pressure sensors are used for combustion feedback control and cylinder balance control. For this HCCI prototype engine, an innovative control system was developed for this complicated system. Control System has two ECUs, one ECU is for cylinder pressure sensor processing, which calculate combustion character values in real time and send to main ECU by CAN bus; another ECU is main ECU, which control injection system, ignition system, heat management system, etc. The control algorithm for mode transition between HCCI and SI was developed. Cylinder balanced algorithm base on CA50 was also developed to optimize emission and engine performance. By the optimized heat management system and control system algorithm, the HCCI engine can get 20 % fuel economy benefit in HCCI mode in part load, and also reach a wider operating range by the combination of turbocharger and EGR technology.

This paper concludes the preliminary findings of a study on the effects of valve timing and manifold air temperature on the combustion performance of a 60 % downsized, turbocharged and supercharged SI engine. Experimental data was gathered on a four cylinder, 2.0 litre prototype engine running at 1,000 rpm, λ = 1 with a constant intake manifold pressure of 2,200 mbar(A) and a targeted exhaust manifold pressure of 1250 mbar. A hybrid experimental approach using Design of Experiments theory guided by 1D simulation predictions was used to derive an efficient experimental procedure using Matlab’s Model Based Calibration (MBC) toolbox in order to minimise the volume of testing required to characterise the engine behaviour at this condition. Experimental data was used to produce empirical models for engine responses such as torque, BSFC and NOx emissions and IMEP coefficient of variance (CoV). The model inputs were intake and exhaust cam phasing, manifold air temperature and spark advance. It was found that quadratic approximations for all of the responses modelled provided acceptable model fit in terms of statistical metrics such as R

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, RMSE and PRESS equivalents. Optimisation studies based on the empirical models to determine the locations of best engine performance in terms of the responses modelled were completed. A maximum torque of 416Nm was predicted at the condition of maximum intake cam advance and exhaust cam retard (maximum valve overlap). This was attributable to an observed peak in engine airflow, a result of favourable manifold pressure pulsation interactions between cylinders. BSFC and at this point was found to be 365 g/kWh. As expected, manifold air temperatures of 28 °C (coldest tested) were predicted to give the best torque performance due to the improved volumetric efficiency and combustion phasing achievable with colder charge temperatures. A minimum BSFC of 219 g/kWh was predicted to occur in the region of 0° intake cam advance and 28° exhaust cam retard (from maximum opening points of 150° aTDC and 126° bTDC respectively). This gain in BSFC however comes at the cost of a 150 Nm drop in brake torque. The reduction in torque output was due to a reduction in engine airflow (a response largely dictated by intake cam phasing). However improved scavenging of exhaust gas residuals and an in-cylinder mixture closer to λ = 1 are likely to have improved combustion efficiency at this point, resulting in a proportionally better BSFC. Small changes in the available combustion parameters have been shown to have significant impact on the combustion behaviour leading to trade-offs in performance and efficiency. Optimisation studies for NOx emissions were also performed, the results of which shall be discussed herein.

Homogenous charge compression ignition gains attention increasingly because of its high efficiency and low emissions. The combustion phase control has been one of the key technological issues which affect its industrialization of HCCI combustion technology. In recent years, ion current detection technology gains more and more attention due to its simple structure, low cost and its containing of large information of combustion. The signal can be used to detect combustion state and to realize closed-loop control of combustion process according to certain strategies. In this paper, the cycle-by-cycle control strategy of combustion phase was established, employed ion current signals and flexible injection strategy of GDI engine. According to ion current signal phase features in two preceding cycles, fuel amount injected in the next cycle will be adjusted to stabilize combustion. The experiments were done based on a GDI-HCCI test bench. The results show the first injection has obvious effect on both combustion and ion current signal phases. The fuel amount injected in the next cycle can be regulated by first injection. CA50 can be predicted by ion current signal difference dImin. The combustion phase can be controlled within 2°CA. The maximum concentration of HC decreased from 18,000 to 4,000 ppm after combustion phase control was applied. The issue of this study is that fuel amount injected need to be calibrated in different work conditions. The detection circuit needs to be optimized because the signal is a little weak under direct injection method.

The Geely GETEC engine family is a key element of Geely’s global blueprint for sustainable development. The members with higher performance and efficiency in the family will replace preceding larger displacement naturally aspirated (NA) petrol engines in a very wide range of vehicle applications, to meet increasingly stringent legislations around the world. It will give the customers significantly improved fuel economy and emissions without compromising driving performance feel, comfort and unaffordable cost.

To satisfy both environmental regulations and better drivability requirements, high-level control of automobile engines is currently in demand, and electrification is in progress. An electric supercharger, in which a supercharging compressor is driven by a high-speed motor instead of an exhaust turbine, improves the transient response of the turbocharger by due to the motor high-speed response. An engine with an electric supercharger offers comparable fuel consumption to a naturally aspirated engine, and is expected to facilitate the downsizing of engines. The electric supercharger prototype consists of a centrifugal compressor impeller and a high-speed motor rotor, supported by grease lubricated ball bearings. In this paper, we explained development of grease-lubricated electric supercharger and electric two-stage supercharger system combined with another turbocharger at 12 V power supply specifications. Specially, this paper introduces the result of the engine bench test and simulation using engine simulation tool (GT-Power). Moreover, we report the performance test results exhibiting a high-speed response of 0.7 s acceleration time to attain a compressor operating point rated at 2.4 kW, 90,000 rpm. As a result of engine test using a 1.5 L gasoline engine, the electric two-stage turbocharger demonstrated the 43 % improvement in a response time at 1,500 rpm as compared with normal two-stage turbocharger. Also, the electric two-stage supercharger was found to be effective in the catalytic activity of the cold start when the turbine outlet temperature over 100 °C higher than the two-stage turbocharger. We aim to accelerate technical development towards production, and to contribute ever tightening CO

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reduction with automobile engines from now on.

Test with optical single cylinder engine, in-cylinder with twin jet layout, dual spark plug ignition conditions, with the combination of calculation of 3D simulation software and experiment, analyzed the effect of different mixture concentration distribution characteristics of different jet and different ignition on the flame propagation, the temperature field, the lean combustion process and NOx emission characteristics. The result showed that the mixture concentration gradient near the spark plug in the organized lean combustion process had a great effect on the flame propagation and combustion stability. The greater the concentration gradient was, the circulation changes would be smaller, the combustion would be more stable, but the NOx emissions would increase; With the use of dual-point ignition, the air flow movement in the cylinder had a “traction” of the incipient flame, the difference moment of formation and of two flame and the interaction of the two flame affected the whole flame propagation; The NO was generated first when the temperature of cylinder was greater than 2,000 K and equivalence ratio was at the range of 0.8–1, within the range of the concentration of the mixture, the increasing of the temperature led to the significantly improving of the NO formation rate, and the maximum NO production rate appeared after the peak of the heat release rate. The thin out mixture led to the decreasing of the peak of heat release rate and the lag of the crank angle corresponding to the position led to the decreasing of NO formation rate.

The aim of this study is the analysis of wear behaviour of a timing chain in real engine operation in terms of the influence of variable operating parameters. Further experiments were carried out with used motor oil. During the wear measurements could be seen, that the variation of the oil temperature showed a minor effect on the wear behaviour. However the use of aged oil showed a significant change of the wear behaviour. This means, that in the design of chain drive systems and oil change intervals this correlation has to be considered for maintaining the targeted engine life. Fundamental experiments on a tribometer using different types of carbon black oil will help to describe this phenomena more accurately.

The objective for this research is to develop LEVIII SULEV technology for midsize passenger cars with SCR equipped diesel engines. The key for SULEV is to lower NOx over the whole emission cycle. From the engine control standpoint, this paper describes a unique NOx reduction technology with three-way conversion reaction until the SCR is heated up. Operating the engine at stoichiometric A/F allows a high conversion efficiency of both NOx and HC using a DOC. Furthermore, it allows rapid heat up of the SCR due to exothermal effect and reduced mass flow. The control system regulates the airflow in order to achieve stoichiometric A/F by controlling EGR flow as first priority. The amount of fuel is determined by the advanced torque control modelled by combustion efficiency so that the A/F can be controlled to stoichiometry maintaining driver requested torque. In combination with the unique SCR system, the FTP75 and US06 emissions test results for NOx + NMHC are below the proposed LEVIII SULEV regulation by a reasonable margin [

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]. Stoichiometric mode is activated to control the NOx before the SCR is activated and when SCR efficiency is dropping at high exhaust flow; Stoichiometric mode supplement for lack of efficiency of SCR to achieve the LEV III targets. Fuel consumption penalty is minimized by a unique stoichiometric A/F control concept where AF target is achieved mostly with EGR control. The base structured engine control has advanced model-based functions such as air management with simultaneous control of VGT/EGR/throttle, torque structure, temperature and pressure estimator and precise A/F control, which are the main enablers to realize stoichiometric control.

Homogeneous Charge Induced Ignition (HCII) is an innovative combustion mode that has the potential to achieve high-efficiency and low-emission combustion. The effects of cooled Exhaust Gas Recirculation (EGR) and hot EGR on the combustion characteristics, emissions characteristics and thermal efficiency are studied contrastively in a light-duty diesel engine. The results show that as EGR rate increased, NOx emissions reduced significantly. Cooled EGR resulted in lower NOx emissions than hot EGR. At low load, Hot EGR can decrease the THC emissions in HCII mode and improve the combustion, with a biggest indicated thermal efficiency increase of 2 %. As EGR rate increased, the NOx emissions decreased and smoke emissions increased in diesel Compression Ignition (CI) combustion at high load, exhibiting the classical NO-soot trade-off. However, in HCII mode, the NOx emissions decreased and smoke emissions were maintained at a low level, which demonstrated that low temperature was achieved apparently. EGR is an effective technology to reduce the combustion noise in HCII mode at high load. As EGR ratio increased, the ignition delay increased in general. Comparing to diesel CI combustion, the ignition delay in HCII mode increased more significantly, which was beneficial to the fuel–air mixing. At high load, the combustion duration in HCII mode was shorter than diesel CI combustion, and the combustion was closer to constant volume combustion, which was conductive to improving thermal efficiency.

The Institute of Combustion Engines and Transport conducted tests on exhaust emissions for two motorized scooters fitted with two-stroke engines differing from each other with the type of the applied pistons. The research was conducted on a chassis dynamometer according to a specially prepared test that aimed at reflecting the conditions of the actual use of the vehicle. The presented tests were performed in order to determine the influence of the lubricant on the exhaust emission components. The authors also tested the in the emission of NOx, CO, HC and CO

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. In the first stage of the testing, measurements were made with respect to a standard mixture of gasoline and oil. Subsequent measuring cycles were conducted for leaner mixtures. The tests on the concentrations of individual components were realized with the use of a portable analyzer SEMTECH DS manufactured by Sensors Inc. The portable analyzer was also designed to measure the mass flow of the exhaust and the concentration of the exhaust components such as CO, HC, NOx, CO

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and O

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. A consumption of fuel with a second by second resolution was measured gravimetrically. The fuel consumption in the test drive was measured with the use of a carbon balance method.

A reliable ignition process is desirable for the ignition of a lean and/or EGR diluted cylinder charge commonly adopted to achieve clean and efficient engine combustion. In this work, ignition of a diluted propane-air mixture is investigated using a high energy spark ignition system. Efforts are dedicated towards development of a novel ignition system that improves the ignition quality whilst keeping within the bounds of current spark ignition hardware to facilitate potential application in future clean combustion engines. A multi-coil ignition system was developed to adjust the spark energy and the discharge pattern. With enhanced primary voltage up to 120 V, a multi-spark strategy with frequency up to 20 kHz can be implemented. The combustion visualization results show that the application of both multi-coil and multi-spark strategy can promote the flame propagation. The high frequency multi-spark strategy shows better ignition quality compared to a single-spark strategy. With discharge energy enhancement by coupling more coils, the ignition success rate is increased under diluted mixture conditions. The diluted combustion limits are therefore extended with the help of these spark strategies.

The combination of turbocharging and direct injection offers a significant potential for SI engines to improve fuel consumption, specific power output, raw emissions and transient behavior. To realize the full benefit of this combination Ricardo uses spray guided lean stratified operation with multiple injections. The Ricardo T-SGDI concept has already been presented at various international conferences and is constantly being developed using modern optimization techniques. This paper shows the latest results of the T-SGDI engine with a maximum brake thermal efficiency about 41 % and a BSFC of about 278 g/kWh at 2000 rpm and 2 bar BMEP. Additionally, the stabilization of combustion through the multiple injections allows EGR rates of up to 35 % in order to reduce NOx raw emissions. Further, this engine achieves 30 bar BMEP and 100 kW/l. These outstanding values are possible by combining different mechanisms such as charging, multiple injection, high Exhaust Gas Recirculation (EGR) rates plus the appropriate charge motion and combustion chamber design. At low loads, the multiple injections ensure stable combustion, even with residual gas fractions of up to 35 %. At medium loads the Ricardo Multiple Injection Variable Injection Separation (MIVIS) Strategy, through the distribution of the injection processes during the intake and compression strokes, in combination with boosting means that the lean operating range can be up extended to BMEP of 15 bar. At WOT, injection during both the induction and compression strokes leads to higher knock mitigation and, above 30 bar BMEP, to 50 % MFB at the thermodynamic optimum. The Ricardo T-SGDI concept thus achieves the efficiency of modern direct injection diesel engines whilst retaining the positive characteristics of a gasoline engine, such as a wide engine speed range and spontaneous power response.

Heavy duty diesel engine cylinder head crack is one of the main problems which affects engine durability. With the increasing requirements for better engine performance, less exhaust emission and lower fuel consumption, increased combustion pressure and elevated temperature make the engine cylinder head to be the most complicated and critical part for the engine design. The objective of this study was to apply cylinder head TMF simulation method to improving cylinder head structure and increasing its TMF life. Machined samples of gray cast iron (GJL 250) taken from cylinder head were used in material tests and material properties under different temperature were obtained from the tests. The finite element model of the whole assembled engine cylinder head/block was built and stress–strain curve were gained by cylinder head cold-hot cycle simulation. Then, cylinder head TMF life was calculated and different life prediction approaches were compared with each other and also with test results. Simulation and test results were generally in good agreement. The position of minimum TMF life from Ostergren approach, which considers mean stress effect, agree quite well with the early crack position of the cylinder head. By optimizing the cylinder head structure, TMF life of the cylinder head was greatly increased. Design standards, the best ratio between valve diameter and the distance of valve centers, maximum valve angle and optimized cylinder head wall, were set for the design of cylinder head of gray cast iron. Based on the creation of the whole assembled FE model of engine cylinder head/block and the application of the cold and hot cycle analysis and life prediction, TMF life of gray cast iron cylinder head were guaranteed at engine early development stage, and time and cost were saved.

Chinese passenger cars market is facing the transition from PFI to GDIT. In a predictable future, PFI engine will still dominate the market. The authors developed a direct injection turbocharged (GDIT) 2.0 L gasoline engine based on a port fuel injection turbocharged (PFIT) engine. The combustion system hardware was optimized by CFD simulations. Thermodynamic calculations were carried out to confirm the performance of turbocharger and the air exchange management system design. The reduced wall thickness design method of block was used and the low friction loss technologies such as Physical Vapor Deposition (PVD) and Diamond-Like Carbon (DLC) were also adopted for engine design. The optimized construction design reduced the engine’s gross weight about 2 kg. The friction loss reduced 10 %. The GDIT engine’s lowest BSFC reaches 238 g/kWh. The GDIT engine’s BSFC at 2,000 rpm 2 bar BMEP reaches 373 g/kWh. The rated power of the engine reaches 145 kW. The maximum torque reaches 280 Nm at the speed of 1,500 r/min.

The first ChineseV6 high performance gasoline engine, named CA6GV, was designed and developed by FAW for it’s executive class car—“Hongqi”, which is the first executive class car of Chinese brand. Achieving the performance of an executive class car was only the starting point, the development target of the engine is to reach the performance of the state of the art of similar V6 engines world wide. The engine distinguishes itself by dual VCT, variable plenum volume plastic intake manifold, 2 stage double side drive silent chain timing system and all aluminium light weight design, low friction technology and dedicated EMS system calibration, the specific torque and power of the engine reached 100 Nm/l and 57 kW/l separately. The engine also have a very good full load torque curve, it can keep above 90 % maximum torque from 2,000 to 5,500 rpm which can provide the car excellent drivability. At the same time, the engine achieves very good part load fuel consumption and excellent NVH behavior. It can also meets the latest emission standard Euro V.

This paper introduces a research work on the air loop system for a downsized two-stroke two cylinder diesel engine conducted in framework of the European project dealing with the powertrain for Future Light-duty vehicles—POWERFUL. The main objective of the work presented in this paper was to test engine air loop system devices selected based on 1D-simulations and to verify their characteristics used for 1D-simulations. With respect to the power target of 45 kW and scavenging demands of the two cylinder two-stroke engine with a displacement of 0.73 l, a two stage boosting architecture was required. Further, to allow engine scavenging at any operation, supercharger had to be integrated in the air loop. Various air loop system layouts and concepts were assessed based on the 1-D steady state simulation at full and part load with respect to the fuel consumption. Among the investigated boosting devices were the positive displacement and centrifugal superchargers driven from the crankshaft and placed upstream or downstream of the turbocharger with either the waste gate or variable turbine. Due to the high boost pressure ratios above five and low mass flows, all boosting devices got at their limits or out of their working range even in the two stage configuration. The simulation part of the work has been presented on SAE World Congress 2012 held in Detroit (USA) (SAE paper no: 2012-01-0831), but the main results will be also presented in this paper to highlight the main issues met during the whole research work. The best compromise regarding the feasibility, power target and fuel consumption was the configuration with the positive displacement supercharger placed downstream of the waste gate turbocharger. However, the biggest drawback of this solution was the necessity of sufficient air cooling between the stages due to the limitation of the maximum temperature at the outlet of the supercharger at 150 °C. On the other hand, the boosting system with the supercharger upstream of the turbocharger required small compressor wheel to avoid surge and was ruled out due to the turbocharger procurement feasibility. After the selection of suitable boosting devices, its testing followed. There had been two types of supercharger tested, Roots type and mechanically driven centrifugal compressor with Continuously Variable Transmission (CVT). Concerning turbocharger, there has been tested device with waste-gate turbine at open loop test rig at different temperatures at turbine inlet. The measured data has been then compared with “paper characteristics” delivered by producers of tested boosting devices for simulation use. The greatest differences in measured and “paper data” had been detected at T/C turbine efficiency.

Main function of a fuel injector used in internal combustion (IC) engines is to properly atomize liquid fuel for vaporizing and mixing with air. In order to achieve good vaporization and mixing, location of the fuel injector inside the combustion chamber is very critical especially in gasoline direct injection engines. In automotive engines, vehicle layout possesses main constraint to mount the fuel injector at a particular location and orientation. In the present study, a conventional carburetor fitted engine was operated with port fuel injection to meet the future emission standards for a two-wheeler application. In general, for gasoline port injection engines, straight cone angle fuel injectors are mainly employed. The direction of fuel spray (cone angle) should be targeted to minimize the wall wetting, which in turn affects the performance and emission characteristics of the engine. Therefore, it is important to study the fuel spray characteristics in these engines. In this study, a CFD analysis has been carried out on a fuel injector to understand the effect of cone angle (8 and 18°) on fuel penetration, droplet size, and evaporation characteristics. In order to carry out CFD analysis, a fuel injector commonly used for Indian two-wheeler application is considered. The geometric model of the injector is generated using ProE software. The model is meshed with polyhedral cells and surface refinement is done at injector and intake pipe regions. The meshed model has a grid density of 0.2 million cells. Analysis has been carried out with inlet air velocity (at the outlet of throttle body) and pressure outlet boundary conditions (cylinder pressure at bottom dead center). Outer surfaces are considered as walls with no-slip boundary condition and intake temperature used was measured from an actual engine, which is used as the boundary conditions. In this study, wide-open throttle position is selected for detailed numerical analysis. Out of the two cone angles considered, 8° is found to be better in terms of lower sauter mean diameter (SMD), fuel evaporation and penetration. However, higher cone angle is found to be better, due to larger spread of fuel and higher probability of getting energy from incoming air so that the size of droplet can be smaller and mixing with the air will be faster, which will enhance the fuel evaporation. At wide-open throttle position, due to higher air velocities, air–fuel mixing is better due to higher evaporation rate with a lesser particle diameter. The CFD results have been compared with steady state measurements in a test bench and the predicted results found to match with experimental results reasonably well with a maximum deviation less than about 6 %.

The isolated sub-models may not yield adequate information to deal with system-level interactive issues in the diesel engine, especially when it comes to transient behavior. In this paper, at first the sub-models, which represent high-pressure fuel system and engine performance in common rail diesel engine, have been described with AMESim code, and fuel injection flow rate and cylinder pressure obtained by measurement are used to validate the sub-models. Then the validated sub-models, together with the sub-model of control system which is made with Matlab/Simulink, have been combined and a powerful complete co-simulation model is established. Intensive validation and application runs are underway. Several initial application runs indicate that the model is very effective in describing and analyzing the transient behavior connections among injectors, high-pressure pump, controller and engine parameters. An example of engine performance variability vs. the variability of injector control-valve-lift is simulated. It is found that the control-valve-lift variation has different impact for idle speed condition and maximum torque condition. Also, several initial runs indicate control strategy has great effect on the characteristic of fuel injection and engine performance, and the fluctuation of engine speed can be greatly reduced if control strategy is optimized.

In diesel engine sprays, smaller sized droplets aid the combustion process, thus reducing emissions. Thus, it is important for diesel engine spray models to satisfactorily represent hydrodynamic mechanisms. A further development of a diesel spray model that uses different size distribution functions has been presented. In this model transport equations are constructed to calculate three moments of the droplet size distribution, a fourth moment is calculated from a gamma size distribution function, while the results of the droplet break up process are derived from an assumed size distribution function. Together these present the complete hydrodynamics characterisation of the diesel spray. The motivation for using different size distributions is to reduce the complexity of the spray modelling process and reduce the computational expense. The model has been applied to high-pressure diesel spray cases with the experimental data characterised by diesel spray penetration at different injection pressure values. The results from the model indicate that diesel spray penetration is over predicted at the start of injection but this improves as the fuel injection progresses.

Numerous experimental investigations make use of diesel surrogates to make the computational time reasonable. In the few studies where measured (surrogate and real diesel) and computed (surrogate only) results have been compared, the selection methodology for the surrogate constituent compounds and the measures taken to validate the chemical kinetic models are not discussed, and the range of operating conditions used is often small. Additionally, most simplified models use tuning variables to fit model results to measurements. This work makes the comparison between some frequently used diesel surrogates using a simple 1D vaporizing spray model, with the spray cone angle as the tuning parameter. Results show that liquid length and fuel fraction strongly depend on the physical properties of the used fuel for a fixed spray angle. These parameters are important for modeling auto-ignition and pollutant formation. The spray angle is varied till the spray length is the same for each surrogate. Results show important differences between other spray parameters such as local mixture fraction and axial velocity.

To facilitate advanced combustion strategies and meet stringent emission regulations of CI engines, the computational models have to accurately predict the injector flow and cavitation development in the nozzle. This paper describes a coupled 1D/2D/3D modeling technique for the simulation of the fuel flow and nozzle cavitation in diesel injection systems.

Research and/or Engineering Questions/Objective

: Diesel combustion process control is very important in optimizing diesel engine performance. There are few controllable parameters in engine fuel path which have effects on the combustion process and hence the engine performance. The objective of this study is to develop a control-oriented, low computational cost diesel combustion model and apply it in combustion process control system design.

Methodology

: The structure of a control-oriented low computational cost combustion model was developed based on sufficient knowledge and comparison of various fuel injection spray and combustion models in literature. The model parameters were identified from a Caterpillar C6.6 diesel engine installed in the Loughborough University laboratory. The model was further validated by the same engine test data both at steady operation points. The model was then used in predicting the effect of fuel path controllable parameters (start of injection and fuel rail pressure) on the engine performance output over all engine operation range. The engine performance output includes NOx and soot emission out and IMEP value for each cycle. This model and the prediction result was finally used in designing a combustion process feedback control system.

Results

: This combustion model was validated to show that it has high accuracy both for engine steady operation point and transient. The simulation result shows the trade-off among NOx and soot emission for varying start of injection and rail pressure. And this trade-off varies with engine speed and load. The engine test results indicate that the combustion process control system designed based on this combustion model and prediction results is able to improve the engine performance compared to look-up table fuel path control system.

Limitations of this study

: The combustion model presented in this paper needs to be expanded to include air path and heat transfer dynamics. Model validation needs to cover VGT and EGR control input variation.

What does the paper offer that is new in the field in comparison to other works of the author

: Developing a control-oriented diesel combustion model; using the model in studying the engine performance space and the controllability of fuel path controllable parameters; and the synthesis of diesel combustion control system are all novel topics.

Conclusion

: A low computational cost combustion model for combustion process control purpose was developed and validated. The application of this model in control system design was implemented and was experimentally proved to be success in improving the engine performance both emission and fuel consumption. The IMEP feedback control either by main injection duration or by PDW is able to reduce combustion variations at steady state and has strong disturbance rejection performance to other fuel path inputs.

Today, 88 % from the total amount of energy used worldwide is represented by fossil fuels (oil, natural gas and coal). Oil dependence required a diversification of fuels in the transport sector in general and road transport in order to stop global warming. Alternative fuels difference slightly in terms of such phisical properties as: density, viscosity and bulk modulus, properties which influence the fuel injection parameters such as penetrability, Sauter Mean Diameter and vaporization rate. The European Union adopted Directive 2003/30/EC to enforce the use of biofuels and other alternative fuels. EU member states must achieve a target of 20 % of alternative fuels used in the transport sector. These lead to different combustion characteristics. The main objective of this paper is to determine the influence of alternative fuels produced by Fischer–Tropsch synthesis from the gasification of biomass used for compression ignited engines.

Based on the Bosch long tube method, an injection rate measurement system is set up. Then several parameters, such as drive voltage, injection timing and injection pressure, are changed independently to study their effects on injection rate. The result shows that: injection pressure and parameters of electrical control signal, such as drive voltage and injection pulse width, have significant effect on injection rate. There are suitable injection pressure and parameters which could optimize injection rate. An empirical formulas about the injection quantity and several parameters are established finally.

Based on X-ray CT scan technology in Shanghai Synchrotron Radiation Facility (SSRF), the inner structure of a side jet single-hole nozzle was obtained and its parameters around the inlet circle were measured. Further researches were carried out with the flow rate test bench about the influences of structure parameters symmetry on the internal flow characteristics and cavitation. Results showed that: the size deviation of inlet diameter, outlet diameter and nozzle length around the inlet circle are relatively small, while the inlet rounding radius is obviously distributed unevenly. Because of that, the cavitation had already showed up when the injection pressure was 40 MPa and the critical cavitation number equalled to 1.032, which should not take place according to the traditional theory. Thus, when relative studies are carried out, it is important for researches to take fully consideration of the size deviation of nozzle structure parameters, especially for the inlet rounding radius, to achieve more reliable conclusions.

Research and/or Engineering Questions/Objective

The performance of injector is very important to gasoline direct injection (GDI) engine control. The influence factors of internal flow characteristics for injector were researched.

Methodology

The Euler multi-fluid model was built and used to analysis. Based on analysis of the internal flow with different mediums and different pressure difference, the flow characteristics of nozzle outlet orifice section were studied.

Results

The discharge coefficient of nozzle was mainly influenced by the degree of cavitation. With the increase of cavitation level, the average velocity added and turbulence energy decreased on nozzle outlet orifice section. The cavitation level was depended on the bubble number density and pressure difference of inlet and outlet of injector.

Limitations of this study

Spray characteristics of GDI injector should be investigated based on the results of this paper.

What does the paper offer that is new in the field in comparison to other works of the author

Most previous analysis of occurrence position for cavitation phenomenon and influence parameters are from macroscopic perspective. This paper mainly analyzes microcosmic influence factors of the cavitation phenomenon within a GDI injector, and then the flow characteristics on orifices export section, which could provide experiential data for later spray simulation, and meanwhile important basis for simulation of the internal flow process.

Conclusion

The cavitation level was mainly influenced by initial value of bubble number density, and increased with it added. Under the same condition, saturated vapour pressure of medium was higher, the influence of bubble number density was much greater. After the bubble number density was greater than 1e + 12, the cavitation flow inside the injector tends to be stable. When pressure difference of inlet and outlet of injector was increased, cavitation intensified.

Spark ignition direct injection (SIDI) gasoline engines employ high fuel injection pressure to promote the liquid fuel atomization and vaporization in the combustion chamber. However, high fuel injection pressures normally lead the fuel spray over penetrating in engine cylinder, resulting in wall and/or piston wetting which cause high level of engine unburned hydrocarbon (UHC) and soot emissions. Recently, it has been found the fuel temperature could play important roles in spray atomization and vaporization processes. Especially, when the temperature of the fuel exceeds its local boiling point, the fuel is superheated and flash boiling occurs. Experiments of flash boiling sprays from a multi-hole DI injector show that the spray would undergo significant structural transformation under the superheated conditions. Both the atomization and vaporization are improved when the phenomenon of flash boiling occurs. Meanwhile, since various types of SIDI engine combustion systems utilize different fuel injector configurations to achieve desirable mixture formation and combustion, it is necessary to extend the existing knowledge of flash boiling spray from multi-hole injector to other types of injector, and characterize their flash boiling spray behaviour under the similar superheated conditions. In this paper, flash boiling sprays from three types of SIDI injectors, namely, multi-hole, swirl and outward opening injectors are investigated at a high pressure constant volume chamber. The primary focus is the spray from a multi-hole injector as it is most widely used in modern SIDI engines. The temperature of the injector body can be regulated by placing the injector in a fixture which can be thermally controlled. Various laser diagnostics are applied to investigate the spray geometry, flow field, vaporization and droplet size distributions. The results show that the characteristics of flash boiling spray are mainly dominated by superheat degree, i.e., the difference between the fuel temperature and its boiling point, not as sensitive to the injection pressure as the non-flash boiling spray. The structures of flash boiling spray from all three types of injector differ from those of non-flash boiling spray significantly. However, the effects of injector configuration on the structure of flash boiling spray are insignificant, compared to the non-flash boiling sprays. This study reveals that using fuel temperature can be an effective parameter for controlling the spray structure, spray atomization and evaporation.

Advanced Vehicle Technologies (AVT), a Ballarat Australia based company, has developed the World’s first diesel to 100 % LPG conversion for heavy haul trucks. There is no diesel required or utilized on the trucks. The engine is converted with minimal changes into a spark ignition engine with equivalent power and torque of the diesel. The patented technology is now deployed in two Mercedes Actros trucks. The power output in engine dynamometer testing exceeds that of the diesel (in excess of 500hp horsepower and 2000 ft/lb torque). In on-road application the power curve is matched to the diesel specifications to avoid potential downstream power-train stress. Testing at the Department of Transport Energy & Infrastructure, Regency Park, SA have shown the Euro 3 truck converted to LPG is between Euro 4 and Euro 5 NOx levels, CO2 levels 10 % better than diesel on DT80 test and about even with diesel on CUEDC tests. The average fuel ratio of LPG tests versus diesel tests over 7 points from 80 to 180 kW is 1.67:1. The conversion is already operational in fleets. The conversion to LPG permits a better economy, a better environment and a better energy security. The truck conversion permits lower operating cost and significantly reduced fuel cost. The LPG has a lower fuel cost per unit energy. The savings are almost $300 per 1000 km. These fuel costs are based on an average wholesale price including rebates over the past sixmonths of $0.51/L LPG and $1.46/L diesel. Longer maintenance intervals also permit lower cost and less downtime. The LPG has significant emissions reduction. The reduced carbon dioxide and particulate matter emissions are a result of the gaseous state and the better C/H ratio of the LPG. The CO2-e advantage of the LPG engine is greater than the tailpipe 10 %. There is almost no particulate matter with LPG. The goal is to achieve Euro 5 (with the Euro 3 engine) in 1st half 2012 with no catalytic converter or urea filter. Finally, the LPG is locally produced and this reduces the dependence on the import of foreign oil. The current conversion kit is for a 3 pedal Euro 3 Actros, 26xx series. The company is working on a kit for the Euro 4 and 5 Actros engine, and also assessing other vendors’ engines for conversion.

The Thermo-oxidation engine Oil Simulation Test (TEOST 33C), one request of the new ILSAC GF-5 specification for passenger car, has been developed as a simulation test to evaluate the “coking” of engine oil in turbocharger. Generally, molybdenum dithiocarbamate (MoDTC) is added into engine oil as an effective friction modifier to improve fuel economy. Zinc dialkyldithiophosphate (ZnDDP) has also been used as a multifunction additive in engine oils for more than 50 years. However, the results of this study showed that the coexistence of MoDTC and ZnDDP in engine oil could cause deposits accretion of the oil in the TEOST 33C. Pressurized Differential Scanning Calorimetry (PDSC) revealed that excess MoDTC led to the oxidative degradation of engine oil and there was no obvious relationship between oxidation stability and “coking” of engine oil. In addition, the elemental analysis of deposits demonstrated that deposits accretion was not caused by the increase ash of MoDTC. In summary, the MoDTC coexisted with ZnDDP might be acted as a “coking” catalyst under high temperature.

The anti-oxidation and fuel efficiency properties of both fresh and aged oils were evaluated using a modificatory Rotary Bomb Oxidation Test (RBOT) and Pressurized Differential Scanning Calorimetry (PDSC). The fuel efficiency properties of a set of engine oils were investigated before and after the aging process. Results of PDSC and SRV indicate that the type of antioxidants, their concentrations, and the ratio of phenol to amine have great effects on the anti-oxidation capability and fuel efficiency retention of the oils. The results show that the use of molybdenum dithiocarbamate (MoDTC) in combination with ash-less antioxidants can lead to pass the Sequence VIB test for fuel efficiency and durability as defined by the ILSAC GF-4 specification.

This study focuses on developing a semi-empirical ignition delay (ID) correlation which is able to predict the ID of various diesel-gasoline fuel blends under steady-state conditions. Prediction from chemical kinetic modelling is compared to experimental data to determine the influential parameters which control the change of ID with operating conditions. Physical and chemical processes are discriminated and the governing factors for both are identified. These governing factors or parameters are fitted into the Assanis’ correlation, and parametric adjustment to the activation energy constant is performed to form the new chemical delay correlation. A physical delay correlation is developed from experimental findings. Finally, an empirical physical delay correlation and a theoretical chemical delay correlation are combined to form the new ID correlation. This correlation produces an average error of 4.9 % and a maximum error of 14 %. It is shown to perform better at high engine speed-load condition (at 2,000 rev/min and 8.5 bar BMEP), with an average error of only 2.6 % and a maximum error of 8.7 %. Physical and chemical processes are shown to be separate events under engine conditions such as steady-state, pre-ignition, fully warmed-up, and undiluted intake air.

The purpose of the one-dimensional numerical simulations done at FTZ (Forschung—und Transferenz Zentrum Zwickau) was to observe the influence of alternative fuels produced from wood biomass on engine energetic parameters like: pressure evolution in combustion chamber, rate of heat release, temperature distribution. The fuels used were represented by blends with 20, 50 and 100 % biomass biodiesel made by the Fischer–Tropsch synthesis. Based on the limitations of one-dimensional simulations, the study included 3D simulations (AVL FIRE) which have correctly estimated the complex phenomena related to diesel fuel injection and combustion.

Nowadays fuel quality standards provide clear instructions for both automotive industry and petroleum industry to produce vehicles and fuels for transportation. In midterm time horizon it will be changed. Fuel mix in the world but mainly in Europe will be much more inhomogeneous as it is know. Fuel development will focus more heterogeneously, different regions will have different energy pathways. Fuel producers have to be prepared for these times: it should be fuel development methodologies, that allow develop new fuel grades based on new recipes, components and additives for new uncommon engine and drive train solutions. In the process of continues fuel development more and more focus has to be done on the different market segments. This is a key factor of success in the fierce market competition of retailers in Europe. Segmentation could be based on utilization conditions, size or also fuel availability and prescriptions. Engines could be utilized at near optimal parameters if the fuel is specified for the conditions. MOL Group’s recent goal was to set up new development methods that allow developing customer oriented fuels for special utilization segments. In our paper we give an overview about the heavy duty fleet testing as an important element to meet the customer expectations. A dual driven—technology push and market pull -development is presented. Carefully organized development process together with internal (refinery, supply chain, logistics, wholesale, retail) and external partners was carried out recently in MOL Group. Based on the already utilized application testing methodology and analytical background we developed a new method for fuel development for special market segments. In the paper we will present our results and work in the example of heavy duty market segment. We present the development goal establishment based on customer value creation, method to find and built up the new test environment and the born of the new product from the idea to the market introduction. We share our experiences in the example of an already fulfilled product development process. Method is developed and already tested on the current European market needs. It has to be proved with great differences, special engine/drive train and energy supply needs, e.g. fuel cell, pure butanol fuel etc.The presented dual driven development method and the example presented in this paper are uniquely summarizes the European fuel trends, market needs and give a successful answer to the challenges. Petroleum industry can remain the primer energy supplier of the mobility if it is able to diversify the fuel portfolio based on the customer’s and vehicle producers’ needs. The presented method and product are good examples how to create synergy between automotive developments and petroleum industry opportunities.

Automotive industries have strong interest in fuel economy. To enhance fuel economy, engine oils need to employ effective friction modifiers (FM). Molybdenum dithiocarbamate (MoDTC) is one of FM and superior in friction reduction performance to other FM especially in boundary lubrication regime. It is said that MoDTC produces MoS

2

layer on the rubbing surface to reduce friction, and ZDDP has a synergistic effect with MoDTC to produce MoS

2

layer effectively. In this paper, we analyzed the rubbing surfaces by several methods after rubbing with SRV tester to clarify the production mechanism of MoS

2

layer. Results by EPMA showed that the combination of MoDTC and ZDDP decreased molybdenum intensity and increased sulfur intensity on lubricating surface compared to MoDTC alone. Results by XPS showed that MoDTC produced both of MoS

2

and MoO

3

layers while the combination of MoDTC and ZDDP produced only MoS

2

layer selectively. Although ZDDP is an important sulfur supplier to MoDTC, at the same time ZDDP and MoDTC are under competing adsorption. We confirmed that a sulfur supplier to MoDTC played a very important role for producing MoS

2

layer.

The objectives of the research project were to establish a test method to evaluate anti-wear performance of engine oil. Comparative research was done about the method and ACEA test method CEC L-38-94 to prove that the two methods have similar evaluation capacity for engine oil. A cam & tappet test rig was set up. The tests which refer to PV5106 were running at certain speed, temperature, pressure and time. Two reference oils of CEC L-38-94 with different wear protection behavior were tested to compare the results with TU3 test data. The same oil was tested two times for repeatability research. The cam and tappet wearing results showed a good repeatability. And the cam& tappet friction test method correlates with CEC L-38-94. This method has simple experimental condition, short running time and single operating condition. It’s unable to completely simulate the actual working condition of engine. But the study certifies cam & tappet friction test method can be used to do wear evaluation. This method provides an effective technology for engine oil evaluation. It also provides convenient and efficient test data for engine oil research. It helps to save research cost and resources which conform to the concept of low carbon.

Owing to increasing oil price caused by risk of oil depletion, many researchers have focused to develop various alternative energies. Biodiesel is one of those energies, which has been a hot-issue recently in automotive industries. Because biodiesel has similar characteristics as diesel, it is possible to use present gas stations, facilities and engine without any modification. It has also an advantage that the emission of biodiesel is lower than conventional diesel engine because it contains oxygen in the fuel. However biodiesel has some problems such as corrosiveness and high viscosity. Therefore, in this study, an experiment was conducted to use biodiesel fuel to solve these problems, and the characteristics of combustion and emission were evaluated according to the use of biodiesel blended with diesel fuel and it was compared with diesel fuel. As a result, we found that biodiesel has benefits of reduction in CO

2

and PM emissions compared to diesel fuel.

Engine oil formulators face a number of challenges when developing modern passenger car motor oils. In recent years greater performance demands have been placed on engine oils to deliver superior oxidation and deposit control protection. This has occurred concurrently with the mandated reductions of phosphorus driven by concerns to protect engine catalyst systems. This has forced the use of lower levels of zinc dialkyldithiophosphate (ZDDP) in modern engine oils. ZDDP is known to be one of the most cost effective antioxidants available. Reductions in its use must be compensated for by the use of other phosphorus-free antioxidants. A challenge exists for the engine oil formulators to identify the most cost effective alternatives to ZDDP while at the same time utilizing inexpensive and rapid, yet meaningful bench test techniques. This paper looks at the use of a bulk oil oxidation test (AlbOT), pressurized differential scanning calorimetry (PDSC), the Caterpillar Micro-Oxidation Test (CMOT) and the Thermo-Oxidation Engine Oil Simulation Test (TEOST-MHT) to evaluate and rank the robustness of passenger car engine oil performance for both oxidation protection and deposit control capabilities. These tests are utilized to screen a number of antioxidant systems in engine oils formulated with 500 ppm of phosphorus derived from ZDDP. The antioxidant components are selected from a series of commonly used and commercially available materials plus some developmental materials. These components include a molybdenum compound, alkylated diphenylamines, hindered phenolics, and new developmental and experimental multi-functional antioxidants. The performance of these fully formulated engine oils are ranked in the selected bench tests in order to highlight the benefits of each antioxidant system under evaluation. Structure activity studies are carried out on a select group of tests in order to gain further insight as to how antioxidant chemical structure impacts oxidation and deposit control performance. The results point to significant performance benefits when multi-functional antioxidants are employed or when the optimum molecular weight antioxidant is selected.

The octane enhancing fuel additive Methylcyclopentadienyl Manganese Tricarbonyl (MMT) is widely used in China to meet market demand for octane in the unleaded gasoline pool, as the use of gasoline of the appropriate octane level is critical to obtaining optimal vehicle fuel economy. The impact of combustion products resulting from the use of MMT-containing gasoline on vehicle emissions control components has long been debated. In order to better understand this issue, a fundamental research program was undertaken to investigate the interactions of combustion products from MMT-containing gasoline with high cell density (600 cpsi) catalysts during severe catalyst operating conditions typical of those used to accelerate catalyst aging for the vehicle durability demonstration process. The paper reports on tests conducted to evaluate the influence of engine running condition, the absence or presence of MMT (at 18 mg Mn/l), and the impact of catalyst inlet temperatures on deposition phenomena occurring at the catalyst face that can lead to plugging. Additionally, a 1000 h test based upon the Type V durability procedure was conducted using MMT-containing gasoline (also at 18 mg Mn/l) to evaluate the impact of the additive under longer term exposure conditions more representative of those dynamic mode operation encountered during typical real-world vehicle operation. Results were consistent with the conclusion that catalyst backpressure was influenced primarily by the test cycle condition, as backpressure increase was only observed during continuous long term exposure of catalysts to MMT-containing fuel at the most severe catalyst inlet temperatures (820 °C) under steady-state operating conditions. Backpressure increase was not obviously observed under dynamic operating conditions regardless of the MMT concentration or temperature.

The main purpose of Exhaust Gas Recirculation system (EGR) is to reduce nitrogen oxides of emissions and to improve the fuel economy when engine at part load. Simulation and a bench test have been done to study the effects on fuel efficiency and the potentiality of increasing the compression ratio of a 1.6 L naturally aspirated gasoline engine by the external cooled EGR technology. One dimensional performance simulation is used to predict the EGR ratio, by analysing engine power, economy and emissions of different amounts of exhaust gas. A bench test is used to calibrate the optimum EGR ratio at each engine operating condition and engine performance, and to analysis the impact on engine performance and operating parameters. The results show that: at the low to medium load conditions, application of the EGR technology only can reduce fuel consumption by up to 2 %, while by increasing the compression ratio and applying the EGR technology, fuel consumption can be reduced by up to 5 %, and reduce NOx by more than 50 %. This study is based on the naturally aspirated gasoline engine. It is an advanced method to apply external cooled EGR technology on a naturally aspirated engine for reducing fuel consumption. Conclusion: The nitrogen oxides of emissions can be reduced and the fuel economy can be improved at part load by using the external cooled EGR technology for a naturally aspirated engine.

Components in NOx storage reduction (NSR) catalysts have been studied in order to identify their impact on NSR performance. In order to enhance the catalytic performance of the NSR catalyst, the hydrothermal stability and sulfur tolerance of the NSR catalyst were improved by developing new NSR formula. The results show that Pt/BaO/Ce

0.7

Zr

0.3

O

2

+ Rh/Al

2

O

3

catalyst has superior NSR activity, thermal stability and sulfur tolerance. The influence of space velocity, oxygen concentration and Lean-Rich period on the NSR activity was investigated.

The maximum soot load capacity for ceramic Diesel Particulate Filters (DPFs) is sometimes limited by a thermal crack failure mechanism associated with high temperature gradients which can occur during regeneration of highly loaded parts—particularly at low exhaust flow rates. The filter material and construction can be optimised for resistance to thermal cracking, however, the precise conditions which give rise to thermal failure of DPFs can be difficult to establish accurately and repeatably. For instance, thermal failure of DPFs may occur at the onset of the heating due to the exotherm of trapped soot, or during cooling (for instance at the fuel cut during deceleration or start of idle). The time of occurrence of thermal failure can help to establish the worst conditions for filters. Sectioning parts post-test is often conducted to establish the nature and location of any damage. However non-destructive testing allows for the possibility of progressive testing of single parts—allowing determination of the ‘Soot Mass Limit’. Post-test scanning techniques have been demonstrated (e.g. X-Ray/CT scanning). These allow non-destructive testing, but are generally expensive, and require the DPF to be removed from the can. This paper describes important considerations for application of two existing post-test evaluations as follows. (1) Radial and axial ultrasound ‘Time-of-flight’ measurement. (2) Internal imaging of the DPF with a small borescope. Also presented are two novel non-destructive techniques for assessing damage to DPFs as follows. (1) An

in situ

technique capable of measuring filter vibration events during DPF operation which may be associated with thermal crack damage. A surface microphone coupled directly to the filter substrate through a hole in the can and intumescent matting measures brick vibration, while a background detector measures exhaust pipe and canning vibration events in order to discriminate metallic thermal expansion. Vibration and internal thermocouple data is presented from exothermic regenerations for several different filters loaded with soot on a commercial Diesel Particulate Generator with standard Diesel fuel and fuel treated with a catalytic additive. The extension of the technique to testing on a vehicle is demonstrated. (2) A relatively simple, post-test evaluation which involves reverse aspiration of DPF test parts with a cold Diesel soot aerosol generated with compressed air. The technique can locate DPF cells where the soot aerosol is not filtered though the substrate between the inlet and outlet channels. The deposition of soot on the substrate is shown to be an indicator of internal damage and, together with simple optical microscopy, can help to identify failure mechanisms. The paper presents examples of the above techniques to examine thermal damage to Silicon Carbide and Aluminium Titanate DPFs which have been subject to ‘worst case’ regenerations.

The intention of this paper is to demonstrate the advantages of the dilution air refine (DAR) system used in emission test for low emission vehicles, especially for formaldehyde emission test. Based on the DAR system, emissions from a passenger car fueled with methanol/gasoline blends (M15) were investigated. The car was tested over the New European Driving Cycle (NEDC). The typical legislated emissions were tested by a Horiba MEXA-7400LE motor exhaust gas analyzer. Formaldehyde was trapped on 2, 4-dinitrophenylhydrazine (DNPH)—coated silica cartridge and analyzed by high performance liquid chromatography (HPLC). Methylbenzene was sampled by Tenax TA and analyzed by thermal desorption-gas chromatography/mass spectrometer (TD-GC/MS). Results indicate that, compared to traditional CVS system, DAR can improve the measurement accuracy by decreasing and even eliminating the background concentration of dilution air, what’s more, it can improve the measurement accuracy of formaldehyde emission effectively which makes DAR to be the preferred test system in measurement of unregulated emissions from light duty vehicles. And on this basis, pollutant emissions from the car fueled with methanol/gasoline blends were investigated. Results show that the car fueled with methanol/gasoline blends (M20/M30/M50) decreased the THC and CO by 39.68–46.98 % and 63.16–65.75 % respectively while increased the NO

X

by 128.91–191.94 %. For unregulated pollutants, methanol/gasoline blends produce formaldehyde 12.06–77.59 % more than the baseline gasoline but the methylbenzene is 34.65–68.73 % less than that. The limitation of this study is that the measurements should be based on more vehicles to get much more exact data. This paper introduces the advantages of the dilution air refine system for the first time which are not mentioned in other papers before. The conclusion of this paper is that the DAR system can improve the measurement accuracy effectively especially for formaldehyde test and the methanol/gasoline blends produce less regulated pollutants and more formaldehyde. This problem can be solved by using additives and new three-way catalytic converters.

The pore structure of DPF is known to have a significant effect on filtration efficiency, pressure drop, and soot oxidation. It is reported that the formation of a nanoparticle porous layer on the surface of the DPF inlet wall promotes soot oxidation [

1

–

3

]. However, the correlation between pore size in the nanoparticle layer and soot oxidation performance, the effect of the layer in actual use environments, and the oxidation mechanism involved have not yet been clarified. The research discussed in this paper therefore formed SiC nanoparticle porous layers of various pore sizes on the inlet wall surfaces of SiC-DPF (creating what will be termed “NPL-DPF” here) using the dip-coating method [

4

]. The NPL thickness was set at 20 μm to help enable uniform coating samples to be obtained. With regard to filter pressure drop without soot loading, results for a bare DPF and a Pt/γ-Al

2

O

3

-coated DPF (catalyzed DPF; Pt = 1 g/L) were virtually identical. For the NPL-DPF, pressure drop increased as pore size was reduced. By contrast, in the case of pressure drop following soot loading (3 g/L), despite the fact that results for pressure drop for the NPL-DPF were higher than those for the bare DPF, they were lower than those for the catalyzed DPF. It is possible to stop deep-bed filtration by forming a nanoparticle porous layer on the surface of the DPF inlet wall [

1

,

5

]. With regard to soot oxidation performance, the T80 of an NPL-DPF (NPL pore size = 350 nm) was found to be 40 % lower than that of a bare DPF and identical to that of a catalyzed DPF. In addition, reducing the NPL pore size enhanced soot oxidation performance. X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), and hydrogen temperature-programmed desorption (H

2

-TPD) results indicated that the SiC nanoparticle surface was covered by a 5 nm SiO

2

oxide film. It was found that these oxidized SiC nanoparticles desorbed oxygen at around 450 °C. This desorbed oxygen promoted the oxidation of diesel soot. In addition, the filtration efficiency of the NPL-DPF without soot loading was 92 % against 78 % for the bare DPF.

The diesel particulate filters (DPF) used to remove particulate matter (PM) in exhaust gas from diesel engines need to have periodical active regeneration for burning PM accumulated in DPF. Since active regeneration is carried out at high exhaust temperatures of 600 °C or more, it involves issues of fuel economy and emissions. This report describes the effort to resolve these issues by taking steps to promote the oxidation of PM and reduce DPF regeneration time by catalyst coated DPF. Attention was focused on Silver (Ag) catalyst, which possesses a PM oxidation function, as a new catalyst. An analysis of the mechanism on the PM oxidation activity, an evaluation of its properties by various model gas testing, and results from evaluation of performance conducted using an engine bench are reported on. As the result of a search for catalyst material that promotes a PM oxidation reaction, it was found that Ag

2

O was a highly active catalyst material. Furthermore, as the result of efforts to achieve greater stability in performance, Ag/Ce material was found to be a catalyst possessing both high performance and stability. The mechanism of Ag/Ce catalyst was analyzed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). As a result, it was found that the supply of oxygen from complex oxides of Ce contributed to the formation of active species Ag

2

O, which played a role in stabilizing performance. In order to presume the performance of Ag/Ce catalyst in practical use, regeneration tests under various different conditions by using a model gas test equipment was conducted. As a result of that, the Ag/Ce catalyst exhibited high PM oxidation performance compared to the conventional Pt catalyst under all the conditions that were conducted. It was also found in regeneration testing by using engine bench that Ag/Ce catalyst showed greater PM oxidation performance, as in model gas testing, by comparison with conventional technology. As the result of DPF regeneration simulation under NEDC mode conditions, a 43 % shortening effect on regeneration time relative to regeneration conditions when using conventional technology was confirmed. Furthermore, the oil–ash, heat and sulfur durability test were conducted by accelerated aging test. It was found that although Ag/Ce catalyst exhibited some reduction of performance due to ash accumulation, no reduction due to heat or sulfur was observed, showing that this catalyst possesses high durability.

System simulation tools are effective in examining complex systems such as those of a hybrid electric vehicle (HEV). However, since most system issues originate in physical phenomena, it is necessary to reproduce the physical phenomena involved in order to resolve the issues. One problem that occurs especially in HEVs is that stopping and restarting the engine frequently can cause emission performance to deteriorate. To resolve this issue, the phenomena that occur in the catalyst must be reproduced accurately. Based on this reasoning, we have developed an exhaust system simulation tool that takes into account catalyst reactions and have experimentally used the tool in an effort to resolve the issue of HEV emission performance. This paper describes the newly developed simulation tool and the application results obtained.

Vehicular ammonia emissions are currently unregulated, even though ammonia is harmful for a variety of reasons, and the gas is classed as toxic. Ammonia emissions represent a serious threat to air quality, particularly in urban settings; an ammonia emissions limit may be introduced in future legislation. Ammonia is not produced within the cylinder of an internal combustion engine in significant quantities. However, having reached its light-off temperature, a three-way catalyst can produce substantial quantities of ammonia through various reaction pathways. Production of ammonia is symptomatic of overly reducing conditions within the three-way catalyst (TWC), and its formation and emission depends on a wide range of factors. This study presents a brief literature review, and later reports on experimental data presenting ammonia emissions data from four Euro 5 passenger cars, using three different petrol fuels. All vehicles were tested on BOSMAL’s chassis dynamometer over the New European Driving Cycle. For three of the vehicles, undiluted ammonia was quantified directly at tailpipe. The fourth vehicle was subjected to further investigations with the aid of Fourier Transform Infra-Red

(

FTIR

)

analysis of a range of compounds, including ammonia. Emission factors observed for the three vehicles are generally low in comparison to other studies, which may be a result of the favourable laboratory conditions, the relatively small, low-emission engines and the driving cycle employed. Second-by-second data obtained from a single vehicle operating on two fuels revealed small but significant differences in ammonia emissions, including the time of the initial ammonia surge. A range of metrics were examined to determine possible correlations between ammonia and other pollutants. No significant correlations were found; there was however some evidence of a trade-off between ammonia and NO

x

. A brief analysis of NH

3

emissions in the context of RNC emissions revealed ammonia to make up roughly 40 % of the reactive nitrogen compounds

(

RNCs

)

released over the duration of the test cycle. Thus, the ammonia emissions observed are low but non-trivial and the issue of ammonia emissions and direct and indirect impacts on air quality is an important research direction. This paper reports on a continuation of an ongoing test programme conducted at BOSMAL focussing on unregulated emissions (including ammonia) from light-duty vehicles and the effects of increased proportions of ethanol in petrol on regulated and unregulated emissions.

The objective of this study was to investigate regulated and unregulated emissions from four motorcycles fueled with gasoline and one flex fuel motorcycle fueled with three different gasoline/ethanol blends. Regulated emissions (CO, HC, and NOx) have been measured with 7000 series Horiba benches. Unregulated emissions (formaldehyde, acetaldehyde and ammonia) were measured with a SESAM series AVL Fourier Transform Infrared Analyzer (FTIR). Tests were conducted over a chassis dynamometer according to the 97/24/EC drive cycle. Pre and post catalytic (pre-cat and post-cat) converter data were collected. The results showed that catalytic converters designed to reduce regulated emissions from gasoline-powered motorcycles produce ammonia emissions as a by-product of catalytic conversion. The results regarding pre-cat and post-cat conversion aldehydes were analyzed and discussed. The main conclusion was that catalytic conversion reduces aldehydes and regulated emissions on the tailpipe but increases ammonia emission levels significantly.

In recent years gasoline engine powered vehicles have been improved significantly in many respects. Technical enablers like downsizing, turbocharging, direct fuel injection (DI), and variable valve timing [

1

,

2

] have allowed for a simultaneous reduction of fuel consumption and improvement of vehicle performance. While still operating predominantly in homogeneous mode, modern downsized gasoline direct injection engines still present engineers with a number of technical challenges, of which many will require the highest level of inventiveness to overcome. Currently, great attention is paid to the further reduction of particulate emission. In this paper, potential approaches for controlling particulate emissions from direct injection gasoline engines are presented. The presentation includes methods for reducing combustion generated particulate emission as well as exhaust aftertreatment technology options. Special emphasis is given to the open technical issues accompanying each of the approaches, including the challenge of maintaining the already achieved performance and CO

2

reduction levels.

With increasing stringent automobile exhaust emission regulations for diesel vehicles advanced emission control systems may require SCR catalysts with substantially improved thermal durability. Zirconia–Titania–Ceria–Tungsten (ZrTiCeW) mixed oxides were evaluated in the selective catalytic reduction of nitrogen oxides (NOx) by ammonia (NH

3

-SCR). The hydrothermal aging and sulfur aging were performed under severe conditions. They were compared with a commercial V/W/Ti SCR catalyst treated in the same manner. ZrTiCeW exhibits the superior NOx conversion performance and higher selectivity. The influence of space velocity, NOx/NH

3

and NO/NO

2

on the NOx conversion were investigated. The presence of NO

2

in the feed (NO

2

/NO = 50/450) boosts the NO conversion in the low temperature range.

This paper presents a new method for feedback control using the Exhaust Gas Recirculation (EGR) valve and Variable Geometry Turbine (VGT) of a diesel engine. The controller effectively counteracts disturbances in NO

x

and PM emissions while maintaining the fuel efficiency. It is shown that by using a new combination of outputs, the controlled system has very good robustness properties. Using a mean-value engine model, which is extended with an emission model, the performance of the controlled system is examined in a simulation study with various applied disturbances; the feedback controller is shown to reduce the variation of emissions and pumping losses by 80–90 %. Compared to open loop control, the feedback controlled system has lower overall emissions by 14 % in NO

x

, 19 % in PM and a simultaneous 0.7 % improvement of the brake specific fuel consumption is achieved.

A novel catalyzed diesel particulate filter (CDPF) consisting of an α-alumina DPF and an alkali-metal catalyst has been developed for the aftertreatment of diesel soot. The α-alumina DPF (Al-DPF) was fabricated in a multi-segmented structure to relieve the thermal stress caused by the relatively high thermal expansion coefficient of α-alumina. The thermal and physical properties of the Al-DPF were analyzed and compared with those of the commercially available cordierite- and SiC-DPFs. The fundamental properties of the Al-DPF, including its particle filtration efficiency, pressure drop, and thermal durability were comparable to those of the conventional DPFs. Furthermore, the soot oxidation activity of the alkali-catalyzed Al-DPF (AC-Al-DPF) was evaluated using a 2.2 L diesel engine test bench. The soot oxidation rate of the AC-Al-DPF was 3-fold higher than that of a conventional Pt/Pd catalyzed SiC-DPF even after thermal aging at 800 °C for 50 h. Several accelerated durability tests were also conducted to clarify the negative effects of sulfur poisoning and ash accumulation on the catalytic activity of the AC-Al-DPF. The AC-Al-DPF demonstrated considerable stability against both sulfur poisoning and ash accumulation, which indicated that the alkali-catalyzed α-alumina DPF could be applied as an effective tool for the emission control of diesel soot.

A Diesel vehicle has higher potential for CO

2

reduction than a gasoline vehicle. However, it was difficult for the diesel vehicle to become a global CO

2

reduction method, because the diesel vehicle cannot meet strict emission legislation such as LEV III legislation in US. Therefore, this research aims to reduce emissions of diesel vehicle to SULEV levels by using a Urea-selective-catalytic-reduction (Urea-SCR) system and unique engine and management controls. In order to achieve SULEV in FTP75 and US06 modes, both HC and NO

x

should be reduced during the warming-up phase of the Urea-SCR system, and extremely high NO

x

conversion efficiency after the warming-up phase is needed. The heat-up control using unique multiple injection and the early usage of exhaust gas recirculation (EGR) are applied to the warming-up phase. The dosing control using an NH

3

sensor is newly introduced to increase the NO

x

conversion efficiency of the Urea-SCR system. When the air–fuel ratio combustion gas is kept at stoichiometric air–fuel ratio, a diesel oxidation catalyst (DOC) can indicate the same three-way conversion effect as a three-way catalyst (TWC) of a gasoline vehicle. The combination of the engine-out NO

x

reduction by massive EGR, the three-way conversion effect of the DOC and the NO

x

conversion effect of the Urea-SCR system is used during the warming-up phase in FTP75 and during acceleration phases in US06. This emission strategy was able to dramatically reduce NMHC and NO

x

emissions in FTP75 and in US06, and achieved the reduction in the emissions below LEV III SULEV category’s required levels.

The question of Diesel Particulate filter regeneration, despite many years of research, is still an existing problem. Currently, at the expense of the filter durability, the rate of variation of the thermodynamic parameters is increased in the exhaust systems in order to burn the particulate matter accumulated in the DPF filter. This is particularly the case for filters fitted in passenger vehicles operated in the urban cycle [

1

–

3

]. During the analysis the authors took into account the synergy of the aftertreatment components and the physical and chemical phenomena occurring in the integrated co-dependent aftertreatment systems in a diesel engine. The paper includes an analysis and results of tests performed under actual traffic conditions on vehicles fitted with modern aftertreatment systems [

4

–

6

]. In the performed tests stress was put on finding the possibility of improving of the DPF deep bed filtration through analysis of PM emission and size distribution. The considered area of investigations has been defined using nanometric composite materials based on highly porous supports of materials that are at the same time ionic conductors. For the research unique equipment has been used for tests under actual traffic conditions, which enabled a full analysis of the interactions of the gaseous emissions and particulate matter. An analysis of the PM size distribution and PM number has been performed during operation under actual traffic conditions.

Diesel particulate filter (DPF) can drastically reduce the mass of diesel PM (Particulate Matter) emission, as well as, it can significantly reduce the concentration of fine particulate, such as PM2.5. In order to study the PM2.5 characteristics and the effect of driving conditions to the DPF filter efficiencies, the suitable filters were installed on the vehicles without any matching and calibration. Under NEDC, PM emission of upstream and downstream of DPF on five commercial diesel vehicles was tested by CVS, and the number concentration and mass concentration of PM was tested by ELPI. The results showed that DPF filter efficiencies can over 92 % for both PM10 and PM2.5 under most operating conditions. However, under a fewer operating modes, such as a 200s period after cold start, and a 50s period before the end of NEDC which is a rapid slowdown period, the efficiencies of DPF filter is low. This paper reports a work on study for the PM2.5 and ultra fine PM characteristics of diesel vehicle with DPF under the different driving conditions, these impact factors for DPF filter efficiency with some conditions, by comparing both of number concentration and mass concentration on the PM size distribution before and after DPF. This paper reports the emission characteristics of PM2.5 and ultra-fine particles before and after DPF filter under different driving conditions. The results show that DPF filter can reduce PM emission significantly, but attention to the control of DPF filter is needed under the rapid slowdown condition.

Currently the advanced UREA-SCR system is one of the most popular technology to meet the strict emission standards as Euro IV or above. In order to reach high NOx conversion and low NH

3

slip, the urea dosing rate needs to be calculated and controlled precisely. This paper describes an advanced UREA-SCR system based on model based control strategy and advanced diaphragm urea dosing pump. The strategy can be seen as a virtual closed-loop control method for the dosing rate calculation, and it was integrated with the advanced diaphragm urea dosing pump for the tailpipe urea dosing. A SCR chemical reaction model was developed to describe the concentration of different spices inside the SCR catalyst. Three different reactions were taken as the foundation of the model, including fast reaction, normal reaction and slow reaction. To simplify the process of calculation, the catalyst model was divided to three cells. In each cell, the NH

3

storage ability was estimated and the results were taken as the feedback signals for the controller. A virtual closed-loop control method was developed to calculate the dosing rate. The model was tuned under different engine running conditions, the exhaust gas temperature was controlled between 250 and 400 °C and the NH

3

/NOx molar ratio was controlled between 0.8 and 1.1. An advanced-diaphragm urea dosing pump was developed to finish the urea dosing activity. The results of transient engine running experiment show that the NOx conversion efficiency can reach 85 % while keeping the average NH

3

slip under 15 ppm, the peak average NH

3

slip under 30 ppm. And the dosing rate error can be controlled less than 3 %.

In this study, the parameters of SCR system which have an effect on NOx conversion efficiency have been investigated. The NOx sensor located in front of SCR catalyst and the urea injector dosing urea solutions to the SCR catalyst play important roles in NOx conversion efficiency of SCR system. First, NOx conversion efficiency has been decreased when NOx sensor reads engine out NOx emissions lower than the actual engine out NOx emissions, because it brings about the lack of urea injection quantity. Second, the NOx conversion efficiency has been also decreased when urea injector doses less amount of urea solution than the system required. Finally, Applying the aged catalyst system (DOC, c-DPF, SCR) and the soot loading amount in c-DPF also have effects on the change of NOx conversion efficiency.

This experimental work focuses on examining the detailed filtration and regeneration processes of diesel particulate filter (DPF) system under reaction with various gas emissions. To visualize these processes, we fabricated a unique thermal reactor visualized through a quartz plate, in which a 2-inch diameter × 6-inch long cordierite filter was placed. The cylindrical filter was bisected to examine internal microstructures. Other major components consist of a series of 6 kW electric heater units and a microscopic imaging system. This bench-scale DPF system is connected to the engine exhaust pipe, from where engine-out exhaust emissions were bypassed to the DPF system at a constant flow rate. The filtration and regeneration processes were then visualized to examine soot loading and oxidation phenomena on the channel surfaces, along with measurements of pressure drops across the filter. The mass of soot loading was accurately measured at the DPF inlet by a tapered element oscillating microbalance (TEOM). As a result, three consecutive filtration stages were identified from the pressure drop data and soot loading video images: (1) deep-bed filtration in which the pressure drop significantly increased, (2) transitional filtration, and (3) soot cake formation in which the pressure drop gradually increased to the end of filtration. The mass of soot loading was also measured at each stage. In the DPF regeneration experiment followed by the completion of soot loading, three different regeneration stages were identified, where the degree of pressure drop tended to be different each other. For regeneration, both raw exhaust emissions and NO

2

-added exhaust emissions were used as reactants for soot. The regeneration with NO

2

-added emissions was performed at two different DPF inlet temperatures, 400 and 500 °C. The results showed that the NO

2

-added exhaust emissions significantly enhanced regeneration by reducing the total regeneration time, while overall regeneration behaviours turn out to be similar between the two different reactant mixtures, both cases showing three different regeneration stages and a similar pressure drop trend.