Proceedings of China SAE Congress 2020: Selected Papers

By applying a directional electric field in the combustion chamber, the charged intermediate products such as ions and electrons, are directionally migrated during the combustion process in the cylinder. By doing so, an ion current signal is formed in the detection circuit to establish a real-time estimation and closed-loop control of the combustion status based on the in-cylinder ion current detection. Based on the published literatures on in-cylinder ion current detection, this paper analyzes and summarizes the formation mechanism of ion currents in gasoline engines, elaborates the skeleton mechanism of ion current formation process, and based on this mechanism, sorts out the related gasoline engine in-cylinder ion current detection system and its principle. Besides, the development stages of ion current detection technology in gasoline engines are summarized, its application potential in FSAE gasoline engine calibration and performance optimization is analyzed. At the same time, by using the developed in-cylinder ion current detection system, the internal combustion engine of FSAE racing car of Chongqing University in the 2020 season is carefully optimized based on engine bench calibration within the engine laboratory of Chongqing University.

This article takes two formula student racing powertrains as the research object. In order to meet the C-weighted sound level limitation required by the rules, a one-dimensional flow combustion model of the engine was established, and a muffler design was developed based on this, while taking into account the dynamic performance of the engine. For the four-cylinder turbocharged engine with a displacement of 600 ml, a through-impedance compound muffler is used to eliminate mid-high frequency noise and mid-low frequency band noise. Meet the design requirements by optimizing the volume of the two chambers. For a single-cylinder supercharged engine with a displacement of 690 ml, a front expansion chamber and a rear dual chamber impedance compound muffler are used to eliminate low-band noise and mid-high frequency noise. Meet the design requirements by optimizing the position and the volume of the expansion chamber and the length of the main muffler insertion tube. Finally, the actual noise spectrum was analyzed using audio acquisition equipment, and various designs and calculations were verified.

With an electric formula racing vehicle as the research object in the paper, a suspension design method with independent roll control function was introduced, and the conclusion that the suspension has different damping requirements in ride conditions and roll conditions was drawn. Compared with traditional vehicles without heave shock absorbers, this type of suspension realizes the decoupling of stiffness and damping in the heave and roll conditions, and different damping characteristics of the vehicles are obtained in ride conditions and roll conditions by adjusting the heave shock absorbers and inboard shock absorbers separately, to improve the vehicle attitude control and steering response. The effectiveness of the design was verified by simulation in the vehicle dynamics simulation software VI-Car Real Time.

This paper proposes a new type of slip ratio observation method and uses it to improve the response speed of the anti-lock brake control system. The model of the anti-lock brake control system is built in the condition of Matlab/Simulink, and the vehicle parameterized model is established on VI-Grade Car-Realtime. Using the parameterized model of the vehicle, joint simulations of open-loop linear braking conditions and closed-loop high-speed obstacle avoidance track conditions are carried out. The results show that the control system can obviously control the slip ratio near the target value and shorten the linear braking distance by 0.2 m; on high, medium and low adhesion roads, the lap times can be improved by 0.04 s, 0.13 s and 0.60 s, respectively.

This paper mainly introduces the process from design calculation, simulation analysis, and manufacturing to testing verification of a ventilated brake disc for a small racing car. In CATIA, a variety of brake disc forms with different numbers of air ducts and heat dissipation ribs are designed. Various types of brake discs are simulated and calculated by using of finite element simulation platform. By comparing the simulation results of different brake discs, the final structural design of the new ventilated brake discs was established. On this basis, a brake disc ventilation flow test device was developed and tested. Simulation and test data demonstrate that the heat dissipation power of ventilated brake discs is 150% higher than that of the solid discs. Road tests show that the average temperature of ventilated brake discs can be reduced by about 16℃ than that of solid discs under typical track conditions.

The FSCC competition limits the power output of the engine due to safety considerations for the participating players. All airflow entering the engine must flow through a 20 mm flow-limit valve (李理光 in 《中国大学生方程式汽车大赛规则》, 2020) [1]. In order to ensure the smooth power and torque output of engine under the restricted air intake rules, the engine air intake system needs to be redesigned. In this paper, a one-dimensional thermodynamic simulation model of the Triumph 675R engine was established and validated based on the calibration test data by GT-Power. On this basis, the length of the intake manifold and the volume of the plenum were optimized. Furthermore, a three-dimensional steady flow simulation of the redesigned intake system was carried out. The result shows that the total intake air mass flow rate of optimized intake system increases from 0.128 to 0.142 kg/s, and the intake imbalance reduces from 3.9 to 0.8%.

Open tires are one of the typical characteristics of formula cars. This structure will bring some difficulties to the design of aerodynamic devices, the main reason of which is the turbulence generated by open tires. How to overcome the tire turbulence is the key technical problem of formula aerodynamic design. This article discusses how to use the vortex generated by the strake to guide and control the tire turbulence, and use CFD to verify. The results show that the leading edge vortex generated by the strakes can indeed improve the negative lift characteristics of the vehicle bottom.

The study is related to the calculation and analysis of Turbocharger matching for FSAE racing engines. In this paper, firstly, the matching requirements and methods between turbocharger and engine are studied; and according to FSC competition rules, a target engine model is established in the engine performance simulation software GT-Power, and the model is verified by simulation calculation in the software; secondly, after calculation, a suitable turbocharger is selected and installed in the engine performance simulation software GT-Power. The model of Turbocharged engine, intercooler and other components is built in GT-Power. Finally, the dynamic performance of the engine matching the turbocharger is predicted by simulation analysis of the turbocharged engine model and bench test, and the simulation results are analyzed.

This paper takes the development of the car frame of the FSAE as the main line, according to the “The rules of the Formula SAE-China”, uses CATIA software to complete the three-dimensional modeling of the car frame, and completes the man–machine engineering verification. Finally, the strength, rigidity and modal analysis of the car frame are carried out by using the workbench module of ANSYS. In order to increase the cockpit space and lengthen the wheelbase, make the car have a certain degree of understeer, the front wheel space is adjusted slightly longer than the rear wheel space in the design; the front ring of the car adopts the hexagon structure, which forms multiple groups of triangle stable structures with the front ring diagonal brace and side anti-collision structure, greatly strengthening the strength and rigidity of the frame.

The full name of FSC is Formula Student China. Students are required to design, process and assemble a racing car within one year. According to the competition rules, the engine displacement used should not be more than 710 ml, and a limiter with a diameter of no more than 20 mm should be set at the intake pipe, which makes the original engine characteristics different from the commonly used racing conditions. The design of the intake system will directly affect the dynamic performance of the engine. The main content of this paper is to optimize the intake design of a 675 ml engine used for FSAE racing. By using CATIA modeling and AVL BOOST one-dimensional simulation, the influence of intake manifold and other dimensions on the engine characteristics is analyzed, and we design the intake dimensions for FSC racing car. Through the boost simulation, 3.5L volume is selected as the final volume of the plenum after considering the layout space. On this basis, the shape of the plenum is modeled and 3D simulated, and the scheme with better outlet mass flow rate and the uniformity of each cylinder is selected as the final result. After considering the layout space, through the simulation of intake manifold length in 90–230 mm, it is found that with the increase of manifold length, the peak value of engine torque gradually moves to low engine speed. Because the commonly used engine speed of FSC racing car is about 7000 r/min, 170 mm is selected as the manifold length finally. Through the simulation of manifold diameter, it is found that in the range of 32–42 mm, with the increase of manifold diameter, the peak value of engine torque gradually moves to high engine speed, and finally the manifold diameter is determined as 34 mm.

Effective measurement and estimation of vehicle state parameters plays a crucial role in vehicle stability control. Among them, the measurement cost of vehicle sideslip angle is higher, and the value obtained by integral calculation in the actual test includes noise, so the accuracy is difficult to be guaranteed. In this paper, a neural network method is proposed to identify the system, and a system model of vehicle sideslip angle identification is established based on the vehicle body state quantity (yaw rate, longitudinal acceleration, lateral acceleration, etc.) which can be easily obtained. According to the experimental conditions, vehicle state parameters were obtained based on CarSim, and Matlab was used for network training. Finally, the network is verified, the applicability of the trained network under different working conditions is discussed, and some assumptions about the optimization of this method are put forward.

This paper presents a planning and control pipeline for an autonomous race car to drive around a track that may not be previously known for three laps. In the case of a limited perception range in the first lap, boundary detection and motion planning separately extract and optimize the trajectory to minimize the trajectory curvature. After finishing the mapping, multi-strategy NMPC is used to optimize or track the trajectory. We use the real-world map data from Formula Student Autonomous China 2019 for experiments. The experiment shows that under the same vehicle model, the system can significantly improve the performance of the race car.

This paper presents a control strategy for the handling stability of a four-wheel drive formula student electric car. The wheel speed correction algorithm based on double track model and the car speed estimation algorithm based on Kalman filter are designed to lay the foundation for good handling and stability control. Based on the hierarchical control theory, direct yaw moment control is divided into three control layers: motion tracking layer, torque distribution layer and slip rate control layer. In the motion tracking layer, combined with the linear two-degree-of-freedom vehicle model, the anti-saturation integral PID algorithm is used to obtain the ideal value of the yaw rate. In the torque distribution layer, an additional yaw moment is generated by the method of equal distribution of inner and outer sides and proportional distribution of front and rear axles to realize the control of the driving stability of the car. In the slip rate control layer, a synovial variable structure control method is adopted to make the actual wheel slip rate the same as the target slip rate. A joint simulation model was built based on Carsim and Simulink, and the control strategy in-loop simulation verification was completed. An electric formula racing test platform was built, and the feasibility of the control strategy was further verified in the four-wheel drive formula student electric car.

In order to further improve the uniformity of the intake system and power performance of FSAE racing engine of Hefei University of Technology, a single variable principle was adopted to determine the relevant parameters of the intake system. In this paper, a 3D model of the intake system was established with CATIA software. The convergent angle of the intake pipe, the curvature radius of the metering valve and the outlet diameter of the intake pipe were determined with Fluent software. Besides, CBR600RR engine model was established by GT-Power software to determine the length of intake manifold. Mechanical analysis and structural optimization of the plenum chamber were done to ensure the stability and strength by the static analysis with ANSYS software.

In order to obtain drive control strategy for multi-motor drive system that take into account both lateral and longitudinal performance of the racing car and at the same time can reconcile the internal conflicts between different strategies. This paper first analyzes the possibility and advantages of coupling multiple control strategies, and discusses the applicability of sliding mode control in multiple control strategies. The drive control strategy is designed for the dual-motor independent drive system, a pedal analysis strategy is built to optimize the control of motor torque by accelerator pedal, the left and right motor torques are reasonably distributed through the electronic differential control strategy, the drive force is reasonably constrained using the traction control strategy, and the coupling is carried out according to the characteristics and logical relationships between the control strategies. Simulation and real-vehicle tests show that the coupled drive control strategies complement each other to further improve the dynamics, stability and handling of the racing car.

This paper aims to develop a practical tire model that keeps the balance between generalization ability and accuracy for Formula Student application. Up to now, the advantages of Artificial Neural Networks for tire modelling have been investigated by some studies, which are briefly introduced in this paper. However, tire models based on Artificial Neural Networks were likely to over-fit the given data, or were sensitive to the noise. And far too title attention has been paid for the generalization ability, which is essential for a tire model. In this paper, a Bayesian regularization method based on the Bayes’ theorem is proposed to solve the major problems described above by improving the generalization ability. And a large number of measured data were used for testing the trained models with different configurations. The results show that the tire models based on the Bayesian regularized artificial neural networks can achieve better generalization ability, and are practical for racing applications such as Formula Student.

Based on the competition rules of Baja Competition of China Society of Automotive Engineering in 2020, this paper designs, analyzes and optimizes the frame structure of Baja racing project. The mechanical properties of the frame are analyzed and verified by the finite element analysis method, and the structure and material properties of the frame are optimized on the basis of mechanical analysis. The mechanical performance of the frame obtained by optimization analysis is more superior, and the lightweight of the frame is realized at the same time. The optimized frame can effectively ensure the safety of drivers, improve race performance, and can be promoted from the theoretical and conceptual level to the level of practical application value, which has a certain reference value for the design of participating students.

In order to improve the accuracy and stability of the driverless electric formula car in the horizontal and vertical control at the same time, this paper proposes a horizontal and vertical coordinated control method for comprehensive analysis of multiple working conditions. First, design a lateral controller based on model predictive control theory, set the optimization objective function, solve multiple constraint conditions to get the real-time front wheel angle. Secondly, design longitudinal controller based on fuzzy PI, solve the real-time longitudinal driving torque according to the vehicle speed error, Finally, analyze the various operating conditions of the car and develop a coordinated control rate, to coupling control between horizontal control and vertical control, and complete coordination control between horizontal and vertical. The simulation analysis results show: The control effect of the coordination method of the driverless electric formula car is better than that of the horizontal and longitudinal independent control, and at the same time, it improves the accuracy and stability of the tracking control on the reference path.

There is noise in the directly heat pump air conditioner system in the electrical vehicle while the heat pump widely using due to its high efficiency and rapid responding speed. The sound source is confirmed to relate to the refrigerant pulsation of the air conditioner system in the vehicle through the experimental analysing. Then the principal of the refrigerant pulsation and the scroll compressor are provided. So the designed muffler which is installed in discharge pipeline of the heat pump air conditioner system in vehicle is used to reduce the refrigerant pulsation into the specification. Thus the vehicle interior noise is reduced significantly. At last the conclusions proved that the NVH performance designing rules in directly heat pump air conditioner system must be considered before.

This research focuses on solving the outer rear-view mirror rain problem and soiling problem of truck. Through the road test and the CFD for truck external flow field, the rain and soiling distribution and mechanism is studied. Through structure optimization and road test on rainy days, the improvement project of exterior components is determined. The results show that the road test and CFD for truck external flow field can simulate rain and soiling and provide optimization advice to designers; and the number, length increase of the front decorative plate spoiler blade, the inlet area and outlet area size and proportion increase of the front decorative plate spoiler and the headlamp spoiler, clearance reduction between wheel well and tyre can decrease the rain attached to the outer rear-view mirror and greatly improve cleanliness on body of the truck. The results of this paper have important reference value for the research and development and modelling design of exterior components of truck body.

This research aims to develop a tail-board add-on to reduce the aerodynamic drag experienced by heavy-duty trucks. When installed at the rear end of the container, the tail-board can delay the separation of airflow in the tail and improve the flow characteristics of tail eddy. In this0 study, the correctness of the heavy truck aerodynamics model is verified by the wind tunnel test of the 1:7.5 reduced model. The drag coefficient and pressure of the heavy-duty truck cruising at 25 m/s are analyzed by CFD simulation. After consideration of the baseline result of Computational fluid dynamics (CFD), the length and angle of tail-board are chosen as design variables for optimization. What’s more, a Kriging approximation model is constructed with 20 experimental points generated by the Optimal Latin Hypercube methodology. As a result, an aerodynamically optimized tail-board for the rear end of truck in which the aerodynamic performance improves by about 11.3% when compared to the baseline vehicle. Finally, 7 different pit-type non-smooth surfaces are arranged in tail-board of heavy-duty trucks to further enhance the drag reduction effect, and the drag coefficient is eliminated by another 2.51%. Therefore, the drag coefficient is reduced up to 13.8% than that of non-mounted trucks.

The spectrum of broadband random vibration contains rich frequency content and continuous feature, which makes it more accurate to simulate the vibration environment of the vehicle compared with the traditional program block fatigue test, so as to more accurately verify the durability of components. However, there are few studies on the compiling method of broadband random vibration spectrum. In this paper, taking the development of random vibration spectrum of integrated electronic brake (IPB) as an example, based on Lalanne’s damage equivalent in frequency domain theory, combined with the vibration intensity estimation method of shock response spectrum (SRS) and extreme response spectrum (ERS), a set of design method of random vibration spectrum is proposed, and the rationality and correctness of the method are proved by practical application, which could serve as a development tool for other similar verification.

In order to solve the long-term problems in the vehicle development process, such as the user’s use load input is not clear, and the proving ground and rig test duty cycles are not consistent with the user’s use duty cycles. In this paper, we propose a new method of truck user usage feature definition. This method takes the geographic information database as the tool, through the establishment of user model, plans the user road and proving ground road measurement routes that conform to the use features of the target user. divides the collected data into sections according to the combination of different factors and their levels, and extrapolate the collected data to derive the user load distribution of the typical user groups. The target reference load is mapped to the proving ground and applied to the accelerated durability test of the proving ground.

Five types commercial vehicles equipped with advanced emergency braking pedestrian system (AEBS_Ped) from different Chinese manufacturers was tested and evaluated in accordance with the traffic industry standard JT/T 1242-2019 performance requirements and test procedures for commercial vehicle AEBS_Ped. The test results show that the braking efficiency of the system is relevant to the time to collision (TTC) and the execution strategy of the braking system. The braking stability and reliability of the same system vary greatly due to the quality of the matching braking system. The system based on millimeter wave radar and camera information fusion is worse than that of pure vision technology due to the effect of fusion algorithm and other reasons. Furthermore, we point out some problems existing in the test and evaluation of commercial vehicle under a single test scenario and put forward some relevant suggestions.

Through fracture analysis, it is confirmed that the cracking of the exhaust pipe heat shield of the exhaust system is thermal fatigue cracking. In this paper, the finite element analysis of the structure is carried out in detail. The thermo-solid coupling analysis shows that the maximum equivalent plastic strain amplitude is located at the cracked weld of the heat shield. Based on this, the structure of the heat shield and the welding fixed position are optimized. The experimental verification shows that the optimized structure meets the design requirements.

Reasonable arrangement of stiffeners is of great significance for improving the strength and stiffness of the transmission housing. Taking the transmission housing of passenger car as the research object, the strength and stiffness of the transmission housing were predicted by finite element method (FEM), and the rationality of stiffener arrangement was evaluated. Then the mechanical analysis of unreasonable stiffener was carried out, and specific optimization measures were put forward from the position, direction, quantity and size of stiffener, so as to improve the mechanical properties of the transmission housing. Finally, the finite element analysis and experimental verification of the optimization scheme were carried out. The results show that compared with the original scheme of the transmission housing, the strength of the optimization scheme is increased by more than 26%, the stiffness is equivalent, and the structure does not have the risk of cracking and resonance. The optimization scheme had passed the bench strength test, which verified that the proposed stiffener optimization measures are effective, and the stiffener optimization measures have certain engineering reference value.

With the increase of chassis lightweight designs, the possibility of chassis structure failure is increasing. The small probability misuse events such as driving through a deep pothole at high-speed, striking a curb on icy road occur frequently. Anti-misuse structure design has become the key path of design. Vehicle prototype misuse test involve the problem extremely cost-intensive and time-consuming modification and validation loops at the development process. In this paper, the vehicle virtual misuse test method was used to study the misuse load, and then based on the load, and the forward control method of chassis failure chain is studied. Through the simulation of chassis deformation, fracture and other behaviors, the failure chain of the chassis was controlled to prevent hidden damage and over-design, which greatly reduces the risk of the structural design and is beneficial to the lightweight of the structure.

In order to solve the problem happened in the market that the high voltage cable of an electric operation vehicle fails and contacts the conductive terminal and the vehicle cannot be started. Failure that occur in market was reconstructed immediately in PSD fatigue bench test, whose input is based on the input of vibration spectrum converted from acceleration signal collected from the user’s public road, in combination with pseudo damage equivalent technique, shock response spectrum and fatigue damage spectrum method. By analyzing the failure mechanism of high-voltage cable fault, the scheme of improved cable joint structure and optimizing cable layout is carried out and verified by bench test. No such problem occurs after the improved structure is put on the market. Within the requirement of identical failure mode and equivalent damage value, the correlation between vehicle users and bench vibration durability test is realized, which greatly shortens the verification period and provides an effective method for the subsequent development and verification of high-voltage cable durability.

Head-type of pedestrian protection needs high requirements for simulation accuracy. In order to improve simulation accuracy, the influence of four types of factors, including structural simulation, simulation settings, subsystem modeling, and material model application, on accuracy of HIC simulation were studied in the form of comparing simulation with tests. The results of the study show that: The geometric difference has a great influence on the simulation accuracy and the average influence level can reach about 20%. After the element size is adjusted from 10 to 5 mm, the accuracy can be increased by 3%. However, considering the accuracy and computing resource requirements, the recommended mesh size of the metal parts in the model is about 5–7 mm on average. The settings of the shell element and solid element, contact and time step size have little influence on the simulation accuracy, all within 5%. The type 16 element should be preferred. In addition, errors caused by the concentration of added mass should be avoided in the calculation. The simulation of heat shield, connection of adhesive, and the inner and outer panel edges of the hood have little influence on the simulation accuracy, at about 1%. Structures such as locks, hinges, bolts, air braces, and wipers are greatly affected by the connection method, and simple rigid connections cannot be used. Reasonable simulation methods should be adopted according to the actual structure. The material cards of headlights and front frame have a great effect on the simulation accuracy, the use of MAT187 material containing failure information is more accurate.

In recent years, adaptive driving beam has become a development trend of automobile headlight, which does not dazzle the drivers of other vehicles, and at the same time guarantees the effect of driving beam to the greatest extent. This paper introduces testing method detail of main performance of adaptive driving beam which required in PRC regulation standard GB4785-2019. In order to meet customers’ needs better, four scenes and testing methods of adaptive driving beam are studied, such as detection distance for pedestrian, detection for electric bicycle light, minimum activating speed and activating under street light.

In the process of driving, the car not only bears the static load, but also bears the uneven excitation from the road surface, the rotation of the engine and other transfer to the body parts of the alternating load. During the trial production of a newly developed model, when the testing comprehensive endurance for 45,000 km were carried out, and the testing results indicated that cracking of spot-welds occurred in the rear floor, rear beam and rear floor panel, and the rear hanging lug and rear floor panel. In this paper, based on integrated design theory on CAE/CAD, the fatigue endurance of the body structure and the multi-body dynamic analysis, the multi-working condition simulation analysis, to find the root cause of spot-welds cracking, through the optimization of structural design and spot-welds layout method, the solution to spot-welds cracking program. After the second road test, the solution is proved to be effective in solving the cracking problem of spot-welds.

Based on the low-speed rear collision condition of C-IASI, established the CAE analysis model of an electric vehicle and analyzed the crashworthiness and maintenance economy. According to the simulation analysis, the plastic strain occurred in the rear end panel, rear floor, rear longitudinal beam, rear longitudinal beam end plate and rear longitudinal beam end plate reinforcing plate. In order to reduce the maintenance cost, proposed a new connection structure scheme. The final analysis results showed that the optimized scheme met the objective.

This article analyzes the characteristics of the side pole impact of electric vehicles compared to fuel vehicles. Electric vehicles not only need to control the amount of collision intrusion, but also need to optimize the acceleration of the body to avoid the impact on high-pressure parts. And because there are battery modules under the front floor of the electric vehicle, in order to avoid squeezing the module, the electric vehicle also needs to specifically control the deformation mode of the seat cross member. Taking an electric vehicle as an example, this paper studies the key energy-absorbing parts of electric vehicle in side pole collision, and optimizes the structure of key energy-absorbing parts through topology optimization and sub-model methods, achieves a weight reduction of 7.2 kg. Full vehicle CAE and test results show that the crashworthiness of electric vehicles has been significantly improved after optimization, which proves that the proposed structural optimization method for side pole impact of electric vehicles is feasible.

To solve the problem of unsatisfactory performance of passive hydro-pneumatic inerter-based suspension with three components in series: conventional container, damper valve and accumulator, an active control method based on passive hydro-pneumatic inerter-based suspension is proposed. After Simhydraulics modeling and experimental validation of the hydro-pneumatic inerter-based suspension, a quarter dynamic model of vehicle active hydro-pneumatic inerter-based suspension (AHPIS) was established and then LQG algorithm was used to adjust the opening of electro-hydraulic servo valve to control the output force of active hydro-pneumatic inerter-based suspension. The co-simulation with Simhydraulics and Simulink shows that compared with traditional active hydro-pneumatic suspension (AHPS), the body acceleration mean square root of the AHPIS is decreased by 18.55%, the tire dynamic load mean square root is decreased by 9.91% and the suspension working space mean square root is deteriorated by 8.91%. The performance of ride comfort and handle stability has been improved greatly. In addition, the engineering application value of hydro-pneumatic inerter-based suspension with three components in series has been improved.

In this paper Factor Analysis method is applied on massive test results of vehicle handling performance. By data reduction the common factors of test parameters are revealed. Based on Factor Analysis method it helps to have better understand on the major factors which is mastering the handling characteristics.

The vehicle state estimation is of great importance for the vehicle dynamics control. A novel method is proposed to estimate the tire force and vehicle state with high precision. The tire vertical force estimation considers dynamics load changes which includes the longitudinal acceleration load transfer, the lateral acceleration load transfer and the roll motion of the vehicle body transfer. The longitudinal speed, the lateral speed, the yaw rate and the tire lateral forces are combined estimated based on combined estimation method. The Co-simulation results based on the Carsim and Matlab/Simulink shows the novel method can estimate the vehicle state with great precision.

With the rapid development of electrification and intelligentization, a controlled-by-wire chassis with the function of four-wheel-independent-driving, braking and steering will become the important trend of automotive due to its more degrees of freedom and higher redundancy. Based on the concept of automotive domain control, this paper proposes a hierarchical control method to realize the motion control of controlled-by-wire chassis. The hierarchical control method includes a motion control layer, a tire force distribution layer, and an executive layer. The off-line simulation proposed in this paper shows that the control method proposed in this paper can improve the stability of the vehicle, and at the same time ensure the safety of the vehicle even if in the condition of actuators failing to realize fault-tolerant control to some degree.

A lot of effort has been put into estimating sideslip angle in varying road friction conditions, but the problem of estimating the tire-road friction coefficient under small tire slip angles has been rarely addressed. An inaccurate estimate of the tire-road friction coefficient, when applied to the estimation of sideslip angle, could cause large errors in the result. This paper studies the estimation of the tire-road friction coefficient in the context of adaptive estimation of the sideslip angle. The nonlinear observability theory is used to analyze the local observability of the system with an augmented state vector that includes the tire-road friction coefficient. The connection between local observability and lateral tire force characteristics is established based on the results of the observability analysis. By studying the performance of the combined state and parameter estimator under weak observability conditions, a modification to the estimator is proposed to keep the observability of the system in an acceptable level even when tire slip angles are small, so that the tire-road friction coefficient can be properly estimated. Test results show that the modified algorithm can effectively improve the accuracy of estimating the sideslip angle under complicated road friction conditions.

The impact comfort is one of the most important attributes of the ride comfort, and the after-shake plays a key role in the impact condition, which affects the driving experience directly. To investigate the effect of system parameters on the after-shake, a simulation model adopting the latest modeling methods is established and DOE (Design of Experiments) is carried out according to the EMDO (Evolutionary Multi-objective Data Optimization) workflow. The results show that the powertrain mount can affect the after-shake remarkably, followed by the suspension and tires. The after-shake can be improved by increasing the mount stiffness and loss angle. However, there are many limitations to enlarge the stiffness of mounts. Such as the idle vibration worsen by increasing the mount stiffness. Given the performance conflicts, a multi-objective optimization method is described.

Accurate and stable estimation of vehicle driving state information is essential for vehicle kinematic control and active safety control. The thesis takes distributed-driven electric vehicles as the research object, and designs an adaptive vehicle driving state estimation method based on the federal-cubature Kalman filter theory. The corresponding nonlinear three-degree-of-freedom vehicle dynamics model is established and the state space equations are obtained. By using information fusion technology to fuse low-cost sensor signals with multiple information sources, and using vehicle dynamics theory to build a vehicle driving state estimator. Select typical experimental conditions and apply Simulink to build the algorithm model and co-simulated with CarSim for verification. Experimental results show that the proposed estimation method can improve accuracy and stability of state estimation.

In order to improve the steering performance of heavy-loaded commercial vehicle under different lateral accelerations, an electric power steering system (EPS) based on lateral acceleration changes is proposed. The influence of lateral acceleration on steering resistance torque and ideal hand torque is analyzed. The four-dimensional assist characteristics considering the variation of lateral acceleration and the control strategy of new EPS system are designed. Through co-simulation, the assist characteristics of new EPS and traditional EPS are compared. It is verified that the new EPS can effectively adapt to the impact of lateral acceleration on resistance torque, make the driver have better steering portability and handling stability, and can obtain clearer steering feeling. At the same time, when the speed is high, the sensitivity of steering system is weakened, reduced driver’s mental burden.

In view of the transverse crack of the longitudinal beam near the upper bracket of the front axle shock absorber of a dump truck frame, the improvement scheme is proposed. According to the actual road conditions of the dump truck, the strain test of the longitudinal beam, the displacement test of the shock absorber and the strain test of the piston rod of the shock absorber before and after improvement are completed. The calibration of the force of the piston rod of the shock absorber is completed in the bench test. The load spectrum of the frame fatigue simulation analysis is obtained by using the strain test results of the piston rod of the shock absorber. A section of frame model is intercepted, the finite element model of frame is established by shell element, and the finite element stress analysis of frame is carried out with HyperMesh software. At the same time, according to the time series load excitation spectrum and the fatigue characteristic parameters of frame material, the fatigue life of frame before and after improvement is obtained by using FEMFAT software. The results of the cloud chart of the frame fatigue life show that the position of the frame easily damaged before improvement is consistent with the actual position of the crack, and the fatigue life of the frame after improvement is significantly improved compared with that before improvement, which verifies the correctness of the fatigue life analysis method, and provides a reference for the fatigue life prediction and structural improvement of the frame.

As a large-tonnage and heavy-duty vehicle, semi-trailer tractors have made tremendous contributions to China’s highway long-distance freight. In order to systematically test and evaluate the performance of the semi-trailer tractor, a test and evaluation system for the semi-trailer tractor was constructed from the perspective of science and generality. On this basis, subjective and objective tests and user surveys were conducted on 5 competing vehicles in the domestic market. The results show that the evaluation system can better reflect the performance of semi-trailer tractors, and has certain reference significance for the product development of related vehicle manufacturers.

Aiming at the path tracking problem of intelligent commercial vehicles, based on the lateral driver model, the optimal preview control strategy is adopted. According to the relationship between the heading angle and the curvature of the path, the heading angle deviation feedback control is introduced. According to the relationship between the speed and the preview distance, a multi-point preview distance determination method with variable weight coefficient is proposed, which improves the effect of path tracking. In order to ensure the stability of path tracking, the model predictive control is used to restrict the wheel sideslip angle, which can improve the stability while ensuring the accuracy of the path tracking. Through co-simulation of TruckSim and Simulink, the optimal preview control and model predictive control are compared. The results show that the optimal preview control has better adaptability to vehicle load, but when the road adhesion coefficient is low, the vehicle will lose stability; while the model predictive control has better adaptability to vehicle load and road adhesion coefficient, and has better driving stability, has more accurate path tracking effect than the optimal preview control.

The latest legislative tendencies for on-highway heavy duty vehicles in the United States such as the feasibility assessment of low NOx standards of CARB or EPA’s memorandum forecast further tightening of the NOx emissions limits. In order to meet such low NOx emission limits, well optimized engine and exhaust gas aftertreatment (EAT) concepts is required. This can be efficiently developed by using the model-based development approach. Furthermore, for such future strict emission limits a precise and robust calibration of engine and EAT control functions is required. In this case, the model-based calibration can improve the calibration quality and robustness and can also be used to reduce the development and testing costs on the test bench. In this study, an overview on different use cases for model-based development methodologies, for commercial powertrain from early concept phase up to the series development and calibration phase is provided. Starting form the early concept phase, the usage of the model-based development approach for optimization of engine and EAT concepts is shown. The interaction between engine and EAT, for instance the influences of different heat-up strategies during the cold start phase are investigated. As the second step, the usage of the model-based approach for a robust and efficient calibration of ECU functionalities is demonstrated for the DOC and DPF functions. Using the model-based approach for calibration of on-board diagnostic functionalities is shown and discussed. Finally, the innovative virtual field testing approach for early detection of possible field issues as a step toward full virtualization of powertrain development is presented and discussed.

China 6 regulation “GB18352.6-2016 limits and measurement methods for emissions from light-duty vehicles” has imported standard RDE test of Europe Union. Impacted by driving style and real road condition, RDE has characteristics as its boundary uneasy to control and bad reproduction. So it is very difficult to realize accurate calibration on real test road. This article aims at analyzing RDE test method indoors. DFTC-RDE test conditions for roller bench usage are built on the basis of the chosen RDE test conditions data of real vehicle and WLTC cycle test results on the roller bench. The results show that this DFTC-RDE roller bench test condition can be used in engine tasks in different powertrain adaptation on vehicle with a coverage of 90%. Instantaneous emission of DFTC-RDE roller bench test condition equals to that of WLTC test condition. It can represent RDE test condition instantaneous emission. Via calibration optimization, DFTC-RDE test condition can be applied to RDE emission test.

Electric car sharing will become an important supplement to the existing traffic modes in the future. The layout of charging station directly affects the convenience of users and the revenue of operators. However, few researches mentioned the layout of charging station of electric sharing cars. This article considered two electric sharing vehicle models, whose driving range were 280 km and 150 km respectively. Energy consumption, purchase cost, vehicle relocation and the state of charge of EVs were taken into consideration to establish a Mixed Integer Programming (MIP) model for the layout of the charging station. The model was validated by the real example of Anting which is in the west of Shanghai in China. The results showed that the layout way in the model can provide an orderly operation process for the car sharing operator, improve utilization efficiency of EVs and reduce operating cost to a certain extent at the same time.

Twin screw air compressor will be widely used in hydrogen fuel cell commercial vehicle because of its high efficiency and strong adaptability, but its noise issue isn’t ignored. For purpose of improving the noise of the compressor, the sound field of a perforated panel muffler based on three-dimensional finite element method was firstly constructed. Then the impacts of different structure parameters on the performance of muffler were investigated. A multi-chamber perforated panel muffler with wide frequency bandwidth was proposed. The noise reduction of the muffler was verified through the experimental study. The results indicate that the resonant frequency decreases with the decrease of the perforation rate, perforation diameter and the increase of panel thickness. Increasing the perforation rate, suitable perforation diameter and panel thickness are conducive to increasing the sound absorption of resonant frequency. There is a noise reduction about 11.4 dBA in average between the inlet and outlet of the muffler when the rotational speed changes from 9000 to 15,000 rpm. When the discharge pressure changes from 1.2 to 2.0 bar, noise reductions are all above 15 dBA and maximum noise reduction is 23.9 dBA.

As the demand for EV’s range increasing, the energy density of power battery is getting higher than before, and the thermal management of battery is becoming more and more important. This article introduces a kind of management system of A/C and battery thermal, and how it works. In addition, the control strategies and parameter settings of core components are explained. The system and control strategy have been experimentally verified and practically applied to certain electric vehicles. The results prove that the liquid-cooled control system and its control strategy described in this paper can well meet the comfort requirements of the passenger compartment. And it can provide a suitable charging and discharging temperature environment for the power battery.

Modelling the comprehensive effects of factors influencing the driving range of BEVs is crucial for eliminating users’ range anxiety and promoting new energy vehicle market. Based on the vehicle operating data and weather data, this paper entangles the effects of road condition, driving and charging behavior, vehicle status and external environment on the driving range of BEVs using fixed effects model by setting DDPSOC (driving distance per SOC) as the explanatory variable. The results provide comprehensive reference for BEV users to predict the variance of driving range, and act as reference for the product design, driving range forecasting strategy of vehicle manufacturers, and the charging infrastructure planning of government.

The driving cycles adaptability of fuel cell has a great influence on the economy, durability and reliability of fuel cell vehicles. Hybrid power system configuration can effectively solve the problem of fuel cell adaptability, but there is still much room for improvement. In this regard, this paper selected an international advanced fuel cell vehicle to test different driving cycles. Based on the test data, the performance of key parameters of each system under different cycle conditions is analyzed in depth from various performance perspectives, as well as the control methods and optimization suggestions behind. This paper provides data support and optimization suggestions for the development of key performance of fuel cell vehicles.

Aiming at the steer-by-wire control system of in-wheel motor electric vehicle. A control strategy of steer-by-wire system is proposed for driving. Using the steering wheel angle and the velocity as input, and establishing the output torque distribution coefficient of fuzzy control rule base. In order to improve the steering stability and sensitivity. The difference between ideal and actual yaw rate is introduced, and the dynamic correction coefficient is obtained by establishing fuzzy controller combine with torque distribution coefficient. The simulation and experiment test results show that the control strategy based on yaw rate difference optimization can ensure the stability of vehicle steering and improve the sensitivity of steering. And effectively avoids the side slip and tail off dangerous conditions when steering.

Reinforcement learning (RL) has been applied to energy management of hybrid electric vehicles to synthesize the system efficiency and adaptability. However, the existing RL-based energy management strategies still suffer the “curse of dimensionality” due to the discretization of the state and control action variables. To cure this disadvantage, a continuous RL-based energy management adopting deep deterministic policy gradient (DDPG) is proposed and applied to a series hybrid electric tracked vehicle. First, DDPG-based energy management strategy is put forward, where two sets of neural networks are adopted to parameterize strategy and approximate the action-value function respectively to eliminate the discretization. In addition, an online updating framework of energy management is carried out to increase the adaptability of the energy management strategy. The simulation results show that the fuel consumption of the online updating strategy is 5.9% lower than that of the stationary strategy, and is close to that of dynamic programming benchmark strategy. Besides, the computational burden is significantly reduced and can be implemented in real-time.

While the carbon coating layer can improve the electrode-electrolyte interface, it is widely used in lithium ion battery modification, the coating procedure remain complex. In this case, a simple solvent method is proposed to fabricate carbon modified LiNi0.8Co0.1Mn0.1O2 (NCM811). The TEM and HRTEM photos reveal that the carbon layer is amorphous and uniformly distributed on the surface of the NCM particles. As cathode materials for lithium ion batteries, the C@NCM delivers an appealing initial reversible capacity of 198 mAh g−1 at 0.1 C (1 C = 180 mA g−1), superior capacity retention of 95.2% after 200 cycles (25 °C) at 1 C, 89.6% after 300 cycles at 2 C, good cycle stability at 60 °C and excellent rate capability of 148 mAh g−1 at 10 C. Such enhanced electrochemical performance is mainly attributed to the smaller electrode polarization and lower charge transfer resistance after carbon coated.

In order to improve the lateral stability, longitudinal dynamics and ensure the driver’s safety, a drive anti-slip control strategy based on multi-knowledge base fuzzy control is proposed. According to the driver’s intention and the characteristics of the adhesion coefficient, the target slip rate of the wheel is calculated. Based on the target slip rate. The vehicle driving mode is divided into the strong longitudinal dynamic mode, the strong lateral stability mode and the neutral balance mode. Different vehicle driving mode correspond to different rules of the knowledge base to control the driving torque of the whole vehicle’s target, so as to achieve the dynamic coordination of the lateral stability and the longitudinal dynamics. Simulink is used to simulate the control strategy. The simulation results show that the designed control strategy can give full play to the dynamic performance of the whole vehicle under various complex and variable working conditions, and at the same time significantly improve the driving anti-skid effect and driving stability of the vehicle.

The estimation of the state of charge of lithium-ion batteries is the prerequisite for fault diagnosis, charge and discharge control, balancing, and SOP/SOE estimation. This paper first uses genetic algorithm to model the battery system based on the practical first-order RC model and improved test methods. In order to reduce the amount of calculation, when using the extended Kalman filter fusion algorithm, the model is simplified, and only the SOC is used as the state for estimation. Then, for the source of SOC estimation noise and the problem that the traditional adaptive extended Kalman filter algorithm is insufficient in accuracy and easy to diverge, An improved adaptive extended Kalman filter algorithm based on moving window and simplified model is proposed. The simulation of NEDC working conditions at different temperatures shows that the results have good convergence and accuracy. The SOC error can be basically guaranteed to be within 1.5% in the full SOC range, which provides a basis for the practical application of engineering.

With the rapid development of the internet of vehicles technology, the remote vehicle control function is widely used in people’s lives. This article focuses on the business process of remote vehicle control function, and analyzes the security risks in the mobile APP terminal, cloud server, vehicle end, as well as the communications among the terminals involved in the business. Aiming at security risk, a system-level security solution is proposed: presenting a mobile phone security solution based on account number, password, and data security; establishing the PKI system, which is beneficial to solve the wireless communication process security problems of mobile phone terminal to the cloud server, and the cloud server to the vehicle end using the digital certificate technology. For the in-car system, detailed security design is carried out from the aspects of architecture, in-car communication, firewall, controller start and debug port, vehicle gateway, and so on. This design scheme can effectively decrease the safety risk in the process of remote vehicle control, greatly improve the difficulty of attack to the system, improve the safety level of the whole vehicle, and provide the security protection ability for the increasing intelligent functions of the networked vehicles.

Trajectory following control is always the focus of intelligent vehicle research. Path following control is an important part of trajectory following control, accurately and stably following the expected driving path given by the upper level programming algorithm is the research difficulties. In order to improve the accuracy and control smoothness of the path following, a two degrees of freedom vehicle lateral dynamic model was established. Through the reverse analysis of the model, a curvature feedforward control model was proposed and analyzed, then the steering wheel angle can be accurately calculated by path curvature. In order to obtain smooth curvature, a constrained arc fitting method was analyzed and proposed to calculate the expected path curvature. Combined with the curvature constrained arc fitting method and feedforward control model, by constantly updating the sample points sequence in expected driving path, the intelligent vehicle path following control model was established. The following result of the path following method and the Multi-point preview control method was compared on the simulation environment. Finally, the intelligent vehicle platform was built based on MicroAutoBox controller, vehicle path following test was used to verify the method proposed in this paper of path following. The results show that the method can accurately follow the expected path, and the steering wheel angle was stable.

Path tracking is the basis for realizing vehicle intelligence, so it is particularly important to realize accurate path tracking. In order to improve the path tracking accuracy of the intelligent commercial vehicle, an optimal preview control strategy with variable weight coefficient multipoint preview is proposed based on the lateral driver model of optimal preview theory. The control strategy improves the path tracking effect by introducing the heading angle deviation feedback control and selecting the optimal preview distance according to vehicle speed because the preview distance is important to the path tracking effect. The control strategy is proved to be more accurate by comparing it with single point preview control strategy and fixed weight coefficient multipoint preview control strategy. Finally, the double lane change path simulation experiment is carried out on variable weight coefficient multipoint preview control strategy. The results show that the control strategy has good adaptability to vehicle speed, vehicle load and road adhesion coefficient under normal driving cycle.

Object-level roadside perception provides strong support for intelligent and connected vehicles, which can promote the application of automated driving in the coordination system integrating vehicles, road infrastructures and clouds. However, sensors must be deployed properly to satisfy the requirements of detection coverage and deployment cost. In this paper, an optimization method of road network sensor deployment is proposed that decomposes the optimization problem in a road network into sub-problems on routes between intersections. The actual detection ranges are calculated under the influence of curve road geometry. A dynamic programming (DP) algorithm is proposed to optimize the multi-type sensor set deployment on each route for full detection area coverage and the minimum deployment cost. To reduce the overlap of detection areas, a search-based adjustment algorithm is designed based on the proposed DP algorithm. Illustrative and comparative examples indicate that the proposed method is feasible and effective.

With the development of the intelligent transportation system, we propose a traffic accident detection system based on roadside traffic monitoring cameras. By combing deep learning-based object detection and tracking technology and expert system-based traffic accident identification technology, a stable traffic accident detection system is implemented in conventional scenarios. In detail, we create a dataset containing 30,000 images, the objects in which are labeled as accident participants, such as pedestrian, bicyclist, tricyclist, car, SUV, bus, and truck. Then the dataset is used to train an object detection and tracking network. Thirdly, we design the rules of accident identification based on spatial temporal constraints. Finally, the system was verified using 40 real road traffic accidents. The experimental results show that the system can achieve 90.91% precision and 81.08% recall.

This paper investigates the over speed test of a heavy duty diesel engine connecting rod bolt joint failure which causing catastrophic engine block ventilation failure. Through using failure mode and root cause analysis, FEA coupling stress analysis, Rod bolt material analysis, Rod machining measurement, Rod bolt tightening and it’s process control, preload check and root cause of connecting rod has been discussed in this paper. Torque and tension study showed excessive Pre-Load on the cap screws using the 75NM + 60° specification. The analysis results suggests that an over-torque situation could lead to a failure. After improvement, the engine validation test was conducted. The abusive test successfully passed, Results indicated that the engine performance and reliability achieve the anticipated development target.

The hydrogen-fueled argon power cycle engine has the potential for high efficiency and zero emissions. Based on constant volume combustion bomb and capacitive spark ignition system, this paper compares hydrogen spark ignition characteristics under different atmospheres, including breakdown voltage and spark ignition energy. It is expected to provide a theoretical basis for designing spark ignition system in terms of reliable spark ignition and eliminating the backfire or pre-ignition caused by the residual energy in the spark ignition system. Research results indicate that the breakdown voltage and spark ignition energy are highest under the CO2-O2 atmosphere, intermediate under the air atmosphere, and lowest under the Ar-O2 atmosphere. When the initial pressure is 0.1 MPa, the breakdown voltage and spark ignition energy under the 79%Ar-21%O2 atmosphere are respectively 2533 V and 64 μJ, respectively 24% and 38% lower than those under the air atmosphere. When initial pressure is 0.3 MPa, with the argon proportion increased from 79 to 88%, the breakdown voltage and spark ignition energy increase respectively by 23% and 49% to 5360 V and 282 μJ. Further researches find that the breakdown voltage and spark ignition energy generally increase with the increasing excess oxygen ratio and the decreasing hydrogen proportion. As the gas density increases with the increasing initial pressure, the breakdown voltage and spark ignition energy increase significantly.

The protrusion between inlet valve seat machining surface and combustion chamber casting surface effects tumble ratio of high BTE (>40%) GTDI engine flow box. Tumble ratio could increase by appropriate step, and decrease by higher or lower step. CFD results show that protrusion machined by one-process can get better tumble ratio than two-processes. Using FEV evaluation methodology, some variants were taken into this research, upper tolerance (+0.36 mm) step shows nearly same charge motion level like nominal flow box (+0.1 mm) and reaches only slightly lower first tumble peak, bottom tolerance (−0.16 mm) step shows lower first tumble peak but at second tumble peak difference are small. All designs in the tolerance reach the same TKE around spark plug at igniting time. It’s a very low and similar wall film level for all steps in the range of tolerance. At last, two prototype cylinder head samples with +0.1 mm and +0.25 mm step were tested on AVL flow test bench. The result shown that the tumble ratio of +0.1 mm step increase 4.3%, but coefficient flow decreases 3.3%, following with CFD result trend.

Investigations on fatigue fracture of steel components for automobile applications have conducted for many decades to ensure the performance at a high level in its service life. In this paper, failure analysis and optimization design for fatigue fracture of low carbon steel bracket fixing oil inlet pipe to automotive engine have experimentally achieved via optical microscopy (OM), spectrometry and scanning electron microscopy (SEM) together with energy dispersive spectrometry (EDS). Therefore, the fracture mechanism and root cause have been determined according to the research results of fracture morphology, microstructure and chemical composition. During the certain platform test the fatigue crack has initiated at the root of fold-typed surface defects of U-typed notch near the bending section resulting from remarkable tendency of stress concentration. The small crack propagates driven by the periodic vibration stress and leads to a final fracture failure. Service performance of the bracket has been improved by optimizing the structural design and controlling the machined surface quality, and the earlier fatigue failure can be consequently avoided.

This paper introduces the analysis process and optimization of the turbocharger actuator system wear issue during the development of VGT turbocharger for the first time on a 1.0 L gasoline engine. After the engine performance degradation, based on the data analysis, it is found that the actuator system is abnormal. Based on the disassembly inspection, it is found that the actuator system is seriously worn. At last, the problem is solved by optimizing the actuator. There are two key points in this paper: 1. Show the characteristics of engine test data when VGT actuator is worn, so as to quickly find out the cause of engine performance degradation in the future; 2. Clarify the design points of VGT actuator system to avoid similar failures in the future.

The influence of solution time, aging temperature and aging time on the tensile properties of Al–6.5Si–3.5Cu alloy was studied by orthogonal test. The results show that aging temperature is the most important factor affecting the tensile properties of Al–6.5Si–3.5Cu alloy, followed by aging time and solution time. With the increase of solution time, aging temperature and aging time, the strength of the alloy increases, but the elongation decreases. When the solution time is 5 h, the aging temperature is 160 °C and the aging time is 3 h, Al–6.5Si–3.5Cu alloy has suitable tensile properties, the yield strength ≥ 240 MPa, the tensile strength ≥ 320 MPa, and the elongation ≥ 2.5%, which can meet the product design requirements well.

In the environment of energy conservation and environmental protection, lightweight is one of the future trend in automobile industry. The application of non-metallic materials is conducive to reducing the weight of existing products, which is in line with the development trend of automotive lightweight. This paper introduces the material selection of plastic fenders. Taking PP + EPDM-T30 as the research object and taking the product performance index as the design requirement, the structural design of the plastic fender is carried out, including wall thickness and installation point arrangement. In addition, the reasonable positioning design ensure the size of the plastic fender. The test results show that the final product meets the use requirements of anti-concavity, impact resistance and vibration durability, and achieves a weight reduction of 38% compared with the steel metal fender.

The application of the microfoam TPV material in glass guide grooves had been researched. Results showed that the performance of the microfoam material meets standard requirements, the product performance of the microfoam TPV glass guide grooves meets the design requirements. This application meanwhile reduces the part weight, realizes the lightweight on such part.

The relative sensitivity concept, which is the ratio of stiffness to mass, is proposed when the inner plate of resin back door is divided into multiple sub-regions in this paper. The variables with certain threshold value are selected as research objects. Then DOE samples are obtained by using Optimal Latin Hypercube method, and Kriging model is established and its accuracy is verified. NSGA-II is used to solve the model, then Prato optimal solution set and best structure are obtained based on the target. The results showed that, the multi-objective optimization method based on Kriging model established in the paper is effective for improving the torsional stiffness of resin back door on vehicle.

The model of thread connection preload is set up and the main factors affecting the performance of thread axial preload are analyzed theoretically. Based on the steel-aluminum connection structure, the test was carried out on the meshing length of aluminum thread, the friction of aluminum support surface, the friction of aluminum thread and the rotation speed by using the tightening system and ultrasonic preload measuring instrument. The results show that the stability of axial preload increases with the increase of the meshing length of aluminum thread. Increase the plain washer to effectively improve the friction state of the supporting surface, axial preload increased by nearly 40%; The friction state of thread was effectively improved by adding wire thread sleeve, and the axial preload was increased by nearly 46%. It is suggested that the proper increase of rotation speed is of certain significance to ensure the reliability of threaded connections.

In today's environment where cost reduction, energy saving and environmental protection are strongly advocated, it is the top priority to maximize the effective power of the engine. Among them, the rotation position of the ignition angle of the engine spark plug is also an important point for the improvement of the effective power of the engine, and the rotation position of the spark plug is determined by its carrier-the thread starting point of the cylinder head spark plug thread hole. However, there are many factors that affect the starting point position: the starting point of the thread cutter during machining, the positioning of the cutter during tool change, the positioning during cylinder head clamping, different equipment in the same process and so on. The consistency of these factors must be determined by the angle position inspection equipment of the starting point of the thread of the spark plug hole. At present, the Advanced, sophisticated, high precision inspection equipment is the control means of the Western engine manufacturing power to this problem. This equipment is not only expensive, but the measurement process takes a long time and the testing process is complicated, resulting in very high testing costs.

The engine hood is an important appearance part of the car, and its matching with the fenders, headlights and front bumper will directly affect the overall sense of the car for consumers. Due to the large surface area of the engine hood and the application of various sealers in the processing process, the engine hood will deform greatly under the action of gravity and thermal stress in the electrophoresis and baking process. The unpredictability of its deformation has become an important issue that perplexes the production efficiency and vehicle appearance quality. In this paper, a finite element simulation model is established according to the production process of our company, and the main influencing factors such as spot welding, hemming and gluing are comprehensively considered. The deformation of engine hood after baking is analysed, and the simulation results are compared with the actual deformation. Finally, a method for simulation analysis of engine hood process deformation is obtained, the simulation results are consistent with the actual situation.

It introduced a stamping process based on three-step of fender, in order to reduce the quantity of dies, and decrease the tooling investment. The product characteristic, stamping formability, and die structure were analyzed. The die quantity of fender was reduced from four-step to three-step by using several compound structures. The side flanging and side piercing, the side restriking and side piercing were arranged in the same step, and the process plan was industrialized application finally. The three-step process was proved to be a feasible plan by practice. So the die quantity was reduced, the stamping efficiency was improved, the die development and production cost were cut down. The quality of three-step process could meet the demand of fender mass production, so there was some reference significance for shorten the stamping process.

This paper researches the business circumstances in the area of the First Automotive Works (FAW) weld-assembly technological management of passenger-car; sorts out the typical problems encountered in the management; explicitly captures core needs in the technological managing. On the basis of the critical requirements, by utilizing the J2EE platform, the paper develops a technological management software (TMS), which has functional modules like process specification designer, process resource manager, PBOM managers, and document manager etc. At the same time, it introduces five typical, specialized application scenarios of the online technological management in detail; proposes an attainable strategy in the weld-assembly technological managing improvements based on web and IT.

Aiming at the problem of DTS out-of-tolerance of brake pedal and accelerator pedal during the pre-production trials of a certain model. Three-pedal tolerance model was established by 3DCS to simulate the manufacturing assembly process. The impact factors and contributions were achieved through three different simulation methods, Monte Carlo, HLM, and GeoFactor. The results show that the contribution of the profile of the brake and accelerator pedal surfaces is as high as 58.97%, and the structure of the brake pedal base has poor robustness. Based on cost, quality, and space layout, this article optimized the structure of the brake pedal base and verified the tolerances. Then brake pedal base and front panel were made quick prototypes, and also verified the matching effect through the actual car. The research methods in this article provide ideas and directions for solving such problems.

In the life cycle of automobile products, the design stage determines the cost of more than 70% of the product life cycle. After the product design is finalized, the space for cost reduction is very limited. Lean design is to reduce unnecessary cost links to achieve high quality, high efficiency and low cost. In the process design stage, by analyzing the Working time\s of the process, integrating the parameters such as DST (design standard time), PST (process standard time), K (impact time on other processes), Δ t (waiting time), the general assembly process will be displayed on the map, and the “congestion” and “detour” judgment models of the process will be established with the time navigation path analysis method, so as to appears the waste in the process design as the way of “congestion” and “detour". Aiming at the process of “congestion” and “detour”, we should improve the process, optimize the process, adjust the process path, and achieve the purpose of eliminating waste and achieving lean process design.

In order to study the influencing factors of battery wrench output torque, a dynamic model is established based on the wrench’s structure. Through calculation, the output speed and battery power are determined as the influencing factors on the output torque, and the angular acceleration (i.e. inertia) has an important influence on the final tightening torque value. With the two factor experiment and two-way analysis of variance method, the output speed is confirmed as the significant influencing factor of the output torque. At the same time, the effect of output speed on output torque is further explored, and the experimental data and theoretical calculation all show that the output speed and the output torque have a clearly positive correlation, which validates the established dynamic model. Within the middle range of the applicable speed, the wrench’s output torque is relatively stable, which has a guiding significance for the selection of parameters and the assembly quality assurance in the practical application. And it has enlightening significance for such as EC tools to optimize the final output torque through the control of the angular acceleration.

The three major American automobile companies have promoted and applied the statistical quality management method of “2 mm” engineering to automobile enterprises all over the world in the 1990s. Under the influence of this view, the concept of function dimension is often applied to the manufacturing process in the early days. With the continuous improvement of consumer’s requirements on automobile appearance gap and flush, the welded white body’s structure and assembly technology become more and more complex. Under this background, the design and application of function dimensions on BIW are very important. This paper gives the design intention and design method of function dimensions by analyzing the body structure and assembly scheme of the vehicle’s front area, which is the most difficult area of vehicle’s exterior DTS. Finally, using the virtual assembly tolerance analysis software analysis verifies the correctness of the design tolerance of the above function dimensions. To some extent, it solves the practical application problem of function dimension’s design in vehicle research and development.

VDA621-415 (ISO 11,997 cycle B) and VDA233-102 are the most important cyclic corrosion tests in product requalification test. The former one is now widely used in domestic corrosion test system, the later one is not so popular due to its high requirement on the equipment. This paper compares the advantages and disadvantages of the two standards from technical parameters and the application history and through a series of test data and test results. It not only fills the ‘blank’ of domestic cyclic corrosion test in application phase, but also provides a better idea for the application of corrosion relevant work in the future, especially for the domestic automobiles.

Automobile manufacturers have attached great importance to the light weight of vehicles and NVH performance. Under this background, laminated vibration damping steel sheets (VDSS) are increasingly used in automotive parts. The engine oil pan stamped from this steel plate has obvious effects on the weight reduction and noise reduction of the engine. For the welding of VDSS, the welding process of single-layer steel plates is generally directly adopted in the industry. However, this process is likely to cause Pin-Hole defects in the VDSS. In products with sealing requirements like oil pans, this defect can easily lead to seal failure. Aiming at eliminate this kind of defect, this article explored the formation mechanism of Pin-Hole defect on the base of experimental results and put forward effective improvement methods. The improvement effect was verified through multiple rounds of routine endurance tests.

The quality data in manufacturing plant is lack of deep mining, relying more on artificial experience and existing quality analysis tools to do data processing. While virtual analysis is more and more used in the stage of engineering development, which is limited by assumptions and cannot be directly used for on-site production guidance and quality analysis. It has been a long time since the gap between theoretical analysis and solution of practical issues existed. Data barrier and the difficulty to form a closed loop between the theoretical and practical analysis have seriously restricted speeding up the product development and launch period. In this paper, a creative quality management solution based on dimensional engineering methodology is put forward, which forms a digital closed loop of upstream and downstream data flows. It can realize the digital interaction of VA theoretical model, measurement points and on-site measured data in an independent dimensional analysis model. Artificial intelligence algorithm is also used to train the model and generate the specific impact factors and sensitivity contribution of on-site quality problems, which can support the data analysis, risk prediction more quickly and accurately.

The problem of squeak noise of body A/B-pillar in the process of road test of a passenger car is studied. By optimizing the parameters related to the baking oven temperature of coating electrophoresis (Heating rate, maximum furnace temperature and holding time), the glass transition temperature of sheet metal electrophoresis coating is improved, and the problem of squeak noise of body sheet metal is solved. The internal relationship between ambient temperature, electrophoretic oven temperature, electrophoretic coating glass transition temperature and squeak noise of body sheet metal are studied. The inner mechanism and solution of squeak noise of this kind of batch body sheet metal are summarized.

In this paper, the acceleration booming noise problem of a pickup truck is taken as the study object, the excitation source is determined as the powertrain by analyzing the test data, and the gearbox mount contributes the most to the booming noise by using the spectrum peak correspondence method. Through the acceleration mobility test and mode test, combined with the Computer Aided Engineering (CAE) simulation analysis method, the problem was determined to be that the mode of the whole frame led to insufficient z-directional dynamic stiffness of the gearbox installation point. CAE simulation method is used to conduct virtual verification of the optimization scheme, and the final feasible and effective design scheme is determined. Finally, the effectiveness of the optimization scheme is verified by subjective evaluation and data test.

The dynamic stiffness of mounting points of a commercial vehicle is researched for the booming noise in this paper. Based on the theory of dynamic stiffness and the modal contribution method, the second-class chassis model of commercial vehicle is established. By means of simulation and verification, it is found that the structural resonance of the supporting beam is the main reason for the insufficient dynamic stiffness of the mounting points which causes the boom in the cab. The further research shows that the problem of booming noise in cab can be effectively solved by improving the mode of supporting beam and the dynamic stiffness of mounting points, which is of extremely important guiding significance for vehicle development.

The NVH performance of the body is one of the most important components of the NVH performance of the vehicle. It is the key system to control the NVH performance of the vehicle. The body is the last link of the transmission system. Almost all vibrations and noises act and reflect on the body and transmit to the passengers. As the system with the largest area on the car body, the panels are easily excited to vibrate and radiate sound. Thus, the rapid identification and control of noise problems are particularly important. Simultaneously, thinning and piercing body sheet metal panels are important directions for lightweight body-in-white, which contradicts NVH performance requirements. Based on the equivalent radiated acoustic power method, the body-in-white model was used for calculation. By analyzing the equivalent radiated acoustic power (ERP) of the body panels and the contribution of ERP, a reasonable structural optimization direction was determined to improve the NVH performance of the panels.

This paper provides an abnormal sound test analysis method based on the analysis of the crank angle,by experimental study on a car which appeared “dada” sound on idle condition. By means of crankshaft angle signal analysis, the characteristic frequencies of the abnormal sound are corresponded to the working period of the engine, and the frequency and delay characteristics of the abnormal sound in the process of structural transmission are studied. Combined with the adjustment of calibration parameters and the analysis of bench test, found that the main source of the abnormal sound is the knock between the intake camshaft and the bearing support. By optimizing the cam profile and changing the valve clearance, the abnormal sound frequency range noise level is improved by about 7 dB, and the abnormal sound in the car is basically disappears.

We present a novel strategy to synthesize pure cubic garnet Li7La3Zr2O12 solid electrolyte at a relatively low temperature (700 °C) by two steps. During the process of obtaining Li7La3Zr2O12, the 8a oxygen vacancy in pyrochlore of La2Zr2O7 was used to occupy the “Li1” 8a site which the information of tetragonal phase Li7La3Zr2O12 requires lithium occupation. The lithium ion conductivity of the obtained cubic garnet Li7La3Zr2O12 as high as 1.7 × 10–4 S cm−1 at room temperature is consistent with the order of record conductivity in the literatures.

In the current vehicle design, mechanical handbrake is widely used as a low-configuration model and often proposed as cost reduction scheme, and because of its frequent use during the driving and the need to meet the convenience of users of different stature, to make sure the comfort layout of mechanical handbrake is still of great importance in the design process. Based on the actual operation process of the user, this paper decomposes the process into nine comfort variables that users can easily perceive, including the initial position of the handbrake, the pull-up position of the handbrake, the horizontal angle of the initial position, the horizontal angle of the pull-up track of the handbrake, the pull-up stroke of the handbrake, the horizontal angle after the pull-up of the handbrake, the distance between the operating point of the handbrake and the human body in Y direction, the Y inclination angle of the handbrake, and the gap between the centerline of the arm and the hand pillow after the handbrake is pulled. In this paper the comfort variables are discussed based on theoretical human body analysis and large database analysis, then summarized into relative comfort range, after verification on the adjustable physical bench, we finally get a comprehensive recommended range of handbrake layout comfort parameters. The final research conclusion can be effectively uesd to guide the project development, to improve the quality of project development, and to ensure the man–machine comfort of product design.

In this article, the multi-link rear suspension of a certain vehicle model was taken as the research object. Based on Monte Carlo Method, the three-dimensional tolerance model of multi-link rear suspension was established in 3DCS. The deviation of four-wheel positioning parameters were analyzed, and also, critical impact factors were identified. The virtual prototype of multi-link rear suspension was established in ADAMS. Then, the safety of toe angle adjustment was verified. The results show that the Y direction adjustment of eccentric bolt of lower pendulum arm in Y direction is within the range of −4 to 4 mm, which can meet the requirements of toe angle adjustment. The toe and camber are approximately linear with the adjustment of the lower arm mounting in Y direction. Further more, the influence of toe adjustment on camber is small.

In the event of a collision, the seat belt can restrain the occupant in the seat to protect the occupant. On this basis, the load limiting function of seat belt can reduce the peak of the impact load on the occupant's chest and reduce the chest injury. In this paper, the load limiting system of the seatbelt is taken as the research object. By establishing the equivalent mechanical model, the design method of the diameter parameter of the torsion bar is obtained. At the same time, the fault tree research tool is used to obtain the important parameters that affect the load limiting stability of the retractor, and then the improvement and optimization scheme is provided. Finally, through sled test and vehicle test, the correctness of the design of load limiting value and load limiting stability are verified. Then we know how it affects the protection effect on rear row dummy, which provides a reference for the design of load limiting characteristics of the retractor.

The pretension function of seatbelt retractor has been widely used in the front row of passenger vehicles. With the release and adoption of CNCAP 2018, the equipment rate of pretension function of the retractor in the rear row has also increased significantly, and the pretension spec adopted by all the seats has gradually become a trend. In this paper, take the pretension function of the retractor as the research object, through the theoretical calculation model of pretension, the pretension amount, pretension force and pretension energy of the retractor are designed. Finally, through the pretension performance verification test, it is found that the pretension amount, pretension force and pretension energy meet the performance of design requirements, and they are consistent with the theoretical model design values. Meanwhile, it provides a theoretical design method for the pretension performance of the retractor, and also provides ideas for the pretension performance design of other types of retractors.

In this study, by considering the mechanical structure and actuation principle of PUEH, the pop-up kinematic model was constructed, and the influence of various parameters on the pop-up time is described. Through the actuator performance test, the influence of actuator lifting force and hood quality on PUEH performance is verified. By the meantime, the influence of PUEH on pedestrian’s head acceleration and HIC injury value is verified by the head impact test. The results show that the lifting force and hood quality is the key parameter affecting the springing performance. The larger the ratio of F to the mass of the bonnet, the faster the springing speed and the displacement. The head peak acceleration and HIC value of the vehicle with PUEH is reduced by 24.4% and 31.6%, respectively. So the result is that PUEH can provide buffer for the pedestrian’s head and reduce head injury.

The aim of the study was to optimize the vehicle front structure for pedestrian protection with an FE aPLI legform model. In this study, an FE buck model was developed representing the front structures of a sedan; an FE aPLI legform model was used to assess the injury risk of the car front structure to adult lower extremities; Latin hypercube design was used to optimize the front structure to reduce the legform injury parameters. The optimized car front structure was further evaluated by a 6-year-old child pedestrian FE model for its protection performance to child pedestrians. The results show that the Latin hypercube design and the buck model can effective to optimize the car front structures by reducing the injury parameters calculated by the aPLI legform model. The optimized car front structure also shows better protection performance to the 6-year-old child pedestrian.

In this paper, two new legform impactors with upper body module UBM and aPLI were used at L0 position base on an SUV vehicle. Compared with the test results of Flex-PLI, some countermeasures and suggestions for SUV correspond to new legforms were put forward. The test results showed: The maximum lower leg bending Tibia2 is aPLI > UBM > Flex-PLI; The ligament elongation MCL is aPLI > UBM > Flex-PLI; The maximum femur bending Femur3 is UBM > aPLI > Flex-PLI. The layout of upper, mid and lower support structures need to be considered mainly for SUV corresponding to upper body module’s new legform impactors. It’s suggested that the three support structures can be fixed in inverted triangle to correspond to the SUV vehicle.

Along with the automobile safety requirements increasing, and the continuous development of active and passive safety technology, resulting in a “pre-crash safety system” (Pre-crash) concept, automatic emergency braking system (AEB) as an important part of pre-crash safety system, while avoiding the collision or reduce the collision strength, but also cause the occupant forward out of position, once the collision occurred, the off position reduces the protection efficiency of restraint system, may increase the risk of occupant injury. But now the research on considering the protective effects of different sitting crew AEB device in crash test condition is still relatively little, based on the real human body and different crash dummy in AEB happens from sampling, combined with simulation analysis, discusses its influence on the crash test results.

In this paper, the differences between the 2017 version of C-IASI and the 2018 version of C-NCAP are analyzed respectively. Based on the side impact test results of an SUV model under both evaluation methods, the differential analysis is carried out from the aspects of MDB quality, MDB posture and impact position, and the vehicle body response as well as dummy injury were compared based on the above difference points. The results show that with the same SUV model structure, the deformation of the front door structure under C-IASI evaluation test is significantly worse than that of C-NCAP, while the rear door structure deformed consistently. From the comparison of the margin value about dummy injury, which can be seen that C-IASI front row dummy torso damage value is higher, while the back row dummy injury value is closer. Above research provides participation for vehicle side-impact safety performance design under different conditions.

Based on the mechanics model of 48 V battery under C-NCAP collision condition, the layout under the co-driver's seat, the “three-point” fixing scheme and the “pull rod” constraint structure were designed. And by using the static theory, the low-cost material strength and plate thickness were designed. Through CAE simulation and C-NCAP vehicle test, the constraint effectiveness of the structure design under the collision condition was verified. Based on this design, about 10 L of luggage space was saved, 50% of layout cost was cut down and 1.5 kg of vehicle weight was lightened.

Based on the actual test and simulation result, the paper selects 4 key factors like front windshield thickness, glass adhesive width, A pillar section structure with body side, and A pillar inner panel thickness from the view of vehicle system. By means of orthogonal test with 4 factors and 3 levels, the sensitive influence factors were found through only few calculations. Finally, the targeted optimization design was performed and the roof crush performance was effectively improved, providing guidance for practical engineering problems.

Gas spring layout is difficulty in the design process of tailgate system, Considering the influence of the environment on the inherent characteristics of the gas spring, it is important to accurately establish a calculation model that is similar to the actual situation when arranging the tailgate gas spring. This article describes such a method: use CATIA software to establish a gas spring support model, and then use a formula editor to establish mechanical equilibrium parameters, and then quickly and accurately obtain the gas spring installation point coordinates based on the parameters, finally, input the gas spring installation point coordinates into the Excel calculation program and define the influence of air temperature on the gas spring parameters, calculate the opening force and closing force at different temperatures and different opening angles, and judge the rationality of the gas spring arrangement based on the generated opening and closing force and temperature graph. This method reasonably and effectively solves the difficulty of tailgate gas spring arrangement: it can accurately calculate the opening and closing force of the gas spring which is similar to the actual situation, saves the arrangement time, and improves the accuracy and scientificity of the design

This paper takes the research and development model of a company's core component software products (new function development) as the research object, through the entire project from the pre-research to mass production stage, and successfully entered the B-sample development stage with the support of partners, and proposed A brand-new software technology research and development model was created, which creatively proposed four points for integration with the mass production product development process, and it worked well in the pilot project. This model fully guarantees the achievement of project objectives, provides a specific implementation path for the organization's pre-research and mass production product development models, and also provides a new methodology for software product development with new technology development.

The purpose of this thesis is to research how to build the comprehensive product homologation knowledge system, which is composed of state policies, local policies, national and industry standards, homologation implementation rules, under the background of the automobile industry's rapid development led by the “five modernizations”, in order to adapt to the auto industry management by more ministries and commissions of the state and the needs of the development of enterprises. And how to improve the quality and efficiency of homologation work through homologation knowledge system. The application of homologation knowledge system in homologation risk control is further researched.

In order to evaluate the cost effectiveness of automobile technology in Chinese market, it is necessary to establish a cost research method for automobile technology. Based on the research methods of automobile technology cost in the world at present, this paper puts forward the research methods of technology cost suitable for the Chinese market. The methods are used to estimate the direct manufacturing cost (DMC), indirect cost (IC) and future technology cost of automobile technology. The research conclusions are as follows: firstly, the relevant manufacturing data of technology should be obtained based on the tear-down method. Direct manufacturing cost of relevant technology should be calculated by combining the manufacturing boundary and manufacturing database of Chinese market based on the manufacturing data. Secondly, the indirect cost of automobile technology should be calculated by combining the advantages of the retail price equivalent method (RPE) and the indirect cost multiplier method (ICM) based on the financial statements of automobile manufacturers in Chinese market and the adjustment factors studied by Environmental Protection Agency (EPA) reports. Finally, because of the complexity of the two-factor learning curve, it is suggested to use the single-factor learning curve to describe the cost progress of automobile technology. Considering that the automotive technology gap between China and foreign countries is gradually narrowing, it is effective to use the learning factors of various technologies studied in the EPA report to describe the learning effect and technology cost progress of automotive technology in the Chinese market. Through the study of various costing methods, this paper can provide a method for Chinese automobile manufacturers to calculate the cost of automobile technology when they make technical route selections.

Lane changing is one of the important behaviours of vehicles during traveling. With the application of advanced technologies such as autonomous driving and internet of vehicles to automobiles, lane changing behaviour of Intelligent Connected Vehicle (ICV) will be significantly different from that of traditional artificial vehicles. The lane changing model is an important microscopic model of traffic flow that depicts the transportation system. This paper depicts the background of ICV, categorizes the existing mature lane changing models, and makes a research review of lane changing models considering ICV and distracted driving behaviours. It is found that ICV lane changing models innovate the original models mainly by integrating the functions of ICV and the original models. However, there are relatively few researches on the lane changing models of distracted driving behaviours.

In September 2019, the Ministry of Industry and Information issued the “Public Consultation on the Amendments to the “Parallel Management Method for the Corporate Average Fuel Consumption (CAFC) and New Energy Vehicles (NEV) Credits (thereafter “the dual-credit regulation”)” (Draft for Comment)”. Based on the change of the “dual-credit” regulation in 2019, the author solves the complete information static game Nash Equilibrium of the auto market, then analyze and predict the impact of the “dual-credit” reform on the development of Chinese 2020 automotive industry, aimed at providing reference for the reform of “dual-credit” regulation.

The physical model of transmission built in Amesim can provide detailed movement process data of the actuators. A method for building a physical model of the powertrain of AMT in Amesim are proposed owing to the advantage above. To verify the accuracy of the model, the launch, gear selecting and shifting control strategy models of an AMT are built in Simulink, and the launch and accelerating process with jump shifting from the 2nd, the 4th to the 6th gear fully loaded on a level road are performed through the Co-Simulation platform of Amesim and Matlab/Simulink. Simultaneously, a bench test of gear selecting and shifting actuator and a real truck test are carried on. The simulation results are close to the experimental data. The simulation and experimental results show that the proposed method has a relative higher accuracy, which can improve the efficiency of AMT control strategy development.

Since the 1990’s most vehicle manufacturers began to ‘downsize’ internal combustion engines while maintaining power and torque through the use of technologies such as turbocharging, direct injection and variable valve timing. Reductions in engine capacity and weight of 50% proved be possible in addition to substantial improvements in fuel efficiency and reduced emission. It has recently become accepted that motors for EVs can be reduced in size and weight by a similar or greater amount, primarily by increasing their speed from the historical limit of around 7000–20,000 rpm and beyond. For the motor design itself, electronic and mechanical innovations to allow this increase in speed have been developing rapidly. There remains a challenge in the development of efficient high speed transmissions to bring the 20,000 rpm motor speed down to a typical maximum wheel speed of 1300 rpm for a vehicle travelling at 160 kph corresponding to a 15:1 overall transmission ratio. High speed transmissions for industrial applications have a long history but for passenger vehicle applications the technical and commercial challenges are very different and the need has only been recognised over the last three to five years. The France based RedHV+ project is one research effort addressing the question of ‘whether it is possible to manufacture, at car cost, a high-speed, high efficiency gearbox operating up to 40,000 rpm …. while at the same time guaranteeing the reliability of the system under automobile conditions’. This paper suggests that ‘toothless’ traction drives may be inherently superior to a more conventional transmission for this highly important EV application. It provides a broad discussion of traction drives and specific information regarding the ‘Silk Drive’ together with the efficiency results for the Silk Drive from testing recently undertaken at the Tsinghua Automotive Research Institute (Suzhou) under the direction of Ultimate Transmissions Pty.Ltd. who are the inventors, developers and owners of the intellectual property associated with the Silk Drive.

This paper introduces the basic principles of shift by wire sensing system, finds several factors that affect the accuracy of the magnetic flux density detection value of the sensor system by Failure Modes and Effects Analysis, and through simulation analysis to determine the degree of influence of a single factor on the magnetic flux density. Based on the probability method, the accumulative error of the above mentioned influencing factors on the magnetic flux density of the final output is determined, that is, the upper and lower limits of the magnetic flux density of the shift by wire sensing system are determined. Based on this result, a reasonable threshold is designed. The detection accuracy of the sensing system is improved and the accuracy of the gear shift determination is ensured. Finally the consistency between the actual value and the theoretical value of the detection result of the sensing system is confirmed through bench test and vehicle verification.

In order to meet increasingly stringent fuel consumption and emission requirements, in the field of powertrains, there is an increasing demand for the development and application of hybrid dedicated transmissions, especially dual-motor hybrid dedicated transmissions. During the application of the dual-motor hybrid dedicated transmission, the layout space and cost have become factors that cannot be ignored. How to find an optimal solution among multiple influencing factors such as performance, space and cost determines the application prospect and market promotion of the dual-motor hybrid dedicated transmission. Based on the above ideas, the Schaeffler Engineering team designed and developed a dual-motor hybrid dedicated transmission with P1/P3 architecture. The dual motor architecture provides the flexible drive modes, and the innovative one-way clutch structure design achieve the targets of low cost and simple structure; besides, the innovative one-way clutch structure design effectively controls the axial length, which optimizes the structure and reduces the cost of the hybrid dedicated transmission, so it can be convenient suitable for three-cylinder and four-cylinder engines. At the same time, a suitable hybrid control strategy was applied to optimize fuel consumption and to ensure smooth drive and reliability of components.

As a new modern design method, modular design method has great help in the analysis of the composition mode, mechanism optimization, system decomposition, reorganization and coordination. Using modular design method in the development of passenger vehicle platform can simplify the problem, make it clear, and get good quality assurance and high cost–benefit. Module division is the most important segment in the automobile modular design, but there is no uniform standard about the division of automobile industry module. This paper introduces the application of module division in platform development, which has certain guiding significance for the subsequent platform development.

The steering resistance torque of the vehicle on low-adhesive road is greatly reduced, so using traditional EPS control strategy may result in the driver's road feeling being reduced or even lost, endangering driving safety. In this paper, the variation of steering resistance torque of different adhesion coefficient roads is analyzed. And two new EPS control strategies of commercial vehicles considering adhesion coefficient based on steering resistance torque and compensation current are designed. Finally, a joint simulation model of TruckSim/Simulink is established, the two control strategies are simulated and verified. The simulation results show that both the two control strategies can improve the road feel of the driver and improve the driving safety on the low-adhesion road while ensuring the steering portability.