Abstract:One of the main challenges for battery electric vehicles （BEV） is a sufficient range. Therefore， a maximized battery volume is desirable in any recent vehicle concept. Suspension， as one of the largest subsystems， has a significant impact on that. Starting from a conventional car with an internal combustion engine （ICE）， a suspension is developed to fulfill new packaging requirements for BEVs， while at the same time maintaining typical requirements concerning driving dynamics. The objective of this study is to use automated methods for suspension development to develop a new steerable suspension concept for an electric propulsion system. The suspension concept was optimized for premium cars with large battery sizes. Moreover， advanced active systems such as air springs and active rear wheel steering with large steering angles were also considered. The concept proposes a packaging solution with a well-tuned kinematic performance which meets typical tuning philosophies. In order to address the resulting high complexity， newly developed methods were used. The kinematic optimization was done with an innovative method， which automatically proposes new hard points， depending on the given requirements. For the design， simplified models were used to represent the shape of sophisticated parts. Therefore， it was possible to automatically judge whether a kinematic concept is feasible from a packaging point of view. The results show， that the new suspension concept can handle the challenge packaging issues and complex kinematic requirements.

Abstract:With the implementation of intelligent and connected vehicle， the application of semi-active suspension has become more extensive. In this paper， the effect of semi-active suspension on vehicle durability is studied. Firstly， a semi-active suspension vibration model is established based on the actual skyhook damping control model， and it is applied to a vehicle-suspension seven degrees of freedom（7DOF） model. Next， the suspension performance evaluation index is determined based on this 7DOF model， and the optimal skyhook damping control coefficient was calibrated. Then， the fatigue damage analysis was carried out based on a typical sedan finite element model using the inertia release method followed by the quasi-static superposition method， with the four-channel vertical force output from the suspension model as stimulation. The fatigue damage key locations of the vehicle body were determined， and the fatigue damage values were compared when using a semi-active suspension and a passive suspension， and it was found that the fatigue life of the former was optimized to a greater extent.

Abstract:The failure of a 6-speed wet dual clutch transmission is analyzed， and it is found that the fracture of resin slider in torsional shock absorber is the main reason for the vehicle losing power. In order to analyze the failure condition and failure mechanism， vehicle starting and full throttle acceleration tests were carried out. It was found that the maximum impact moment of the torsional shock absorber was 928N·m when the engine temperature was -2~5℃， and most of the maximum impact moment occurred in gear shifting and full throttle acceleration in low gear condition. To explore the failure mechanism， a torsional vibration mechanical model of drive system was established， and the inherent characteristics were analyzed. The results show that the second natural frequency （11.51Hz） of the first gear unengaged state of the system is close to the peak frequency （8-13Hz） of the starting condition in the test， and the resonance slider is easy to be damaged. The results show that the large instantaneous impact mo ment and the system resonance during the starting process are the main reasons for the fatigue failure of the slider.

Abstract:A data driven classification method based on wavelet scattering collaborative deep sequential neural network is studied to achieve intelligent braking noise recognition. Wavelet scattering transform is used to extract the features of caliper vibration signals relating to braking noise， which form the multidimensional wavelet scattering feature vectors. These feature vectors are input respectively to a standard one layer 1D convolutional neural network （1DCNN） and a one layer bi-directional long short-term memory （BiLSTM） network. The testing results show that the accuracy for braking noise classification can be improved significantly by both networks input with multidimension features from wavelet scattering transform compared with one-dimension features from Shot-time Energy and Shot-time mean zero crossing rate. Modified 4-layer deep 1DCNN and 3-layer deep BiLSTM network are further proposed to reduce training underfitting from standard one layer networks to enhance the capability of feature capture and further improved the classification accuracy. According to F₁ indicator the 4-layer deep 1DCNN shows a better overall performance than that of 3-layer deep BiLSTM network， which also has advantages of fewer training parameters.

Abstract:The flow around the 35° Ahmed model is numerically explored by using three different turbulence models （the realizable k-ε （RKE）， the Spalart-Allmaras （SA）， and the shear stress transport k-ω （SST）） and four different velocity convection schemes （the linear upwind （LU）， the linear upwindV （LUV）， the localblend， and the total variation diminishing （TVD）） based on OpenFOAM. Then， two other software platforms （FLUENT and STARCCM+） are also used as references. It shows that the numerical results of RKE and SST are more reasonable than those of SA. The stable LUDSV and localblend convective scheme both partly weaken the wake oscillation caused by numerical instability， but only the TVD scheme entirely suppresses this oscillation behavior. The drag coefficients predicted by the three software platforms are all in good agreement with those of the experiment， and the error of OpenFOAM using TVD is the smallest， only 0.7%. In addition， OpenFOAM and STARCCM+ can obtain a more reasonable and similar three-dimensional wake flow structure， while FLUENT overestimates the strength of the streamwise C-pillar vortex.

Abstract:Integrated aerodynamic performance of a luxury sports sedan， including aerodynamic resistance， lift force， and wind noise， was studied and optimized. Taking a clay-rigid material mixed full-scale model and its 1：1 digital model as main research objects， an in-depth， full-scale wind tunnel test and numerical simulation were conduct on shape surface， bottom guard plate， aerodynamic hub and sealing strip of the vehicle. A wind resistance coefficient of 0.269， a greatly optimized driving stability， and wind noise level were obtained. This paper introduces the specific engineering experience and relevant theoretical support obtained in the development process.

Abstract:The effects of three MIRA bodies， i.e.， squareback， fastback， and notchback， on the aerodynamic resistance of three vehicles in platooning are numerically explored at one-vehicle spacing. A detailed analysis of the resistance of the whole vehicles and individual parts as well as inter-vehicle flow under 27 different platooning configurations shows that the back pressure of the head vehicle rises due to the blockage of the middle vehicle. All three types of head vehicle can achieve resistance reduction for themselves. The resistance of the middle vehicle will be affected by the back pressure rebound， weakening of the front positive pressure and front edge arc negative pressure due to the combined effect of the head， middle， and trailing vehicles. Thus， some cases of the middle vehicle in platooning have a low resistance and some have a high resistance. The pressure and resistance changes of the trailing vehicle is similar to those of the middle vehicle in view of the combined effect of the middle and the trailing vehicle types. The low-speed wake region of the preceding vehicle is beneficial to the resistance reduction of the following vehicle， but it will also reduce the suction of the arc at the front edge of the following vehicle， which has a negative effect on the platooning drag reduction， and even increases the whole resistance. The best configuration of the three-vehicle platooning is the fastback head vehicle， squareback middle vehicle， and the notchback trailing vehicle with a resistance reduction of up to 0.12（120 counts）.

Abstract:A numerical research is conducted on a low-resistance electric vehicle with or without front wheel spoiler， rear wheel side plate， and rear wheel deflector. By comparing the aerodynamic force， surface pressure， and the computed result of flow field， the effects of low-resistance accessories on the aerodynamic characteristics of these working conditions are evaluated. The result indicates that compared with the basic condition， when removing only the front wheel spoiler， the rear wheel side plate and the rear wheel deflector， and removing both the rear wheel side plate and the deflector， the total resistance of the vehicle is increased by 3.0 %， 6.5 %， －1.8 %， and 1.2 % respectively. The main contribution to the change in the total resistance of the low-resistance vehicle came from the front and rear wheel areas， underbody， and base. The low-resistance attachments mainly affect the underbody obstruction indirectly by changing the flow field in the wheel area， which in turn changes the wheel-body aerodynamic interaction， thereby affecting the aerodynamic characteristics of the low-resistance vehicle.

Abstract:In reduces scaled wind tunnel （RSWT） tests， if the wheel speed is set to the same as the wind， it will double the tire rotation angular velocity， making it more difficult to design a scaled model. At the same time， it will cause a greater instability. Therefore， it is necessary to analyze the effect of tire speed on wind resistance in RSWT tests to explore the feasibility of tire speed reduction tests. Based on a MPV， the influence of wheel rotation speed is analyzed using wind tunnel test and the computational fluid dynamics （CFD） method. The result shows that the tire speed has an impact on the wind resistance test results. The wheel speed setting of the scaled model is the same as the incoming flow， and the scaled model is more consistent with the full-scale wind resistance results.

Abstract:Inadequate land availability is a common engineering issue for automotive wind tunnel planning. To ensure no compromise of the design criteria for nozzle area and test section length， a compact airline design has to be adapted for smaller land occupancy. Meanwhile， the core wind tunnel specifications such as flow qualities and energy ratio shall also be guaranteed with no concession. Using computational fluid dynamics （CFD） simulation， the study has performed risk assessment regarding flow separation and secondary flows in shorten diffusors. Dimensions and spacing distance of turning vanes has been optimized as well for best flow uniformity and turbulence level at the exit of corner 4. Wind tunnel land occupancy ratio is proposed as the economic specification of wind tunnel engineering. Compared with the basic design， the compact airline gives approximately 30% saving of land occupancy.

Abstract:In recent years， a number of new wind tunnels for the automotive industry have been built across the world， and more such facilities are planned for the near future. Many decisions made in the early planning phase of the wind tunnel shape the facility throughout its operating life and contribute to both the construction and operating costs of the wind tunnel. The intent of this paper is to outline that with an appropriate choice of the test section geometry of 3/4 open-jet wind tunnels. The flow interferences that occur due to the finite cross section of the jet in a conventional wind tunnel can be largely compensated for or reduced to a negligible extent. It is shown that for a wide range of vehicles with varying degrees of blockage， residual interference becomes surprisingly negligible， so that a correction of the measured quantities is not required and conditions of “free” air flow are generated in the test section. Furthermore， it is shown that the coarse dimensions of a test section can be much smaller than is often the case today without affecting the quality of the measurement results， which leads to lower construction costs， but above all to lower energy requirements for the operation of the system. It is shown that the instabilities of the free jet must also be assumed， which results in an upper limit for the jet length that should not be exceeded.

Abstract:The flow field quality of the vehicle climatic wind tunnel and climatic chamber directly affects the accuracy of the vehicle thermal and aerodynamic performance test results in a climatic laboratory. By combining experiment and the CFD method， the flow field differences between climatic wind tunnel and climatic chamber were studied. First， the primary flow field parameters， such as speed uniformity， boundary layer thickness， kinetic pressure stability and axial static pressure gradient were tested. Using the CFD method， the flow field numerical values were simulated for climatic wind tunnel and climatic chamber. By comparing the overall flow field characteristics of the climatic wind tunnel and climatic chamber， the factors affecting the difference of flow field quality were analyzed. The experimental and numerical simulation results showed that the flow field quality of the climatic wind tunnel was obviously superior to that in the climatic chamber， such as speed uniformity， boundary layer， axial static pressure gradient， kinetic pressure stability， air flow， and wind speed distribution.

Abstract:Sound source identification based on beamforming is an important experimental method for the study of vehicle aerodynamic noise in wind tunnel. In order to better understand and apply this test technique， a series of simulation were conducted. The influence of factors such as array shape， source frequency， distance between array and testing object， and incidence angle of sound wave on the performance of the array was studied and validated with designed corresponding experiments. The results show that the increases of test distance and incidence angle will worsen the spatial resolution. As source frequency increases， the system spatial resolution becomes better， but the dynamic range worsens. As deviation of the distance between array and testing object increases， the identified source intensity decreases. Furthermore，the sensitivity of different source frequencies， testing distances， and array shapes to sound source amplitude errors caused by testing distance deviations varies. As the source frequency goes higher， testing distance becomes shorter， the sensitivity becomes higher accordingly. The mutual influence of multiple sound sources reduces the effective dynamic range of the array， while increasing the intensity of the sound sources. Afterwards， based on the full-scale DrivAer clay model， the sound sources distribution of the vehicle exterior was identified with beamforming array. Finally，the difference in sound source recognition results of rearview mirrors with different shapes was analyzed using the sound source subtraction method， which demonstrates that this technique can provide a powerful support for the development of vehicle wind noise.

Abstract:In this paper， the simulation domain of the aerodynamics and aeroacoustics wind tunnel is established through actual measurement， taking into account the connection between the test section and the outside world， the fluctuating pressure， and the transient air flow exchange， so as to better reproduce the flow characteristics and unsteady characteristics of the flow field in the test section of the wind tunnel. The comparison between the numerical simulation results and the wind tunnel measurement results in the characteristic physical quantities such as velocity distribution， static pressure gradient， wind tunnel pressure balance outlet， buffer flow outlet and other representative flows and pressures shows that the numerical simulation results in the wind tunnel simulation domain can better fit the actual flow characteristics of the wind tunnel. The real vehicle model is used to conduct numerical simulation in the wind tunnel simulation domain and the traditional cuboid simulation domain respectively， and the results are compared with the wind tunnel test results. The results show that the numerical simulation results in the wind tunnel calculation domain are closer to the wind tunnel test results.

Abstract:This paper introduces the characteristics and the process in NRC wind tunnel test of a heavy-duty truck in Canada. Based on some information in the test report and the calibration method for closed wind tunnels， the correction method of NRC wind tunnel is deduced and the correction formula is obtained. The original data are processed with the derived correction formula， and the results are in good agreement with the test report， which proves the validity of the derived formula， provides reference for the aerodynamic test of heavy trucks in the closed test section wind tunnel.

Abstract:Deep learning-based perception algorithms have gained importance in autonomous vehicle perception systems in recent years. Since the training data cannot cover all critical scenarios and corner cases， how to ensure the safety and reliability of deep learning-based perception functions in crucial scenarios is still an open challenge. Conventional approaches test the driving functions in real-life environments， which can be risky and uneconomic to validate in corner cases. Virtual scenario-based simulation validation approaches can generate a large number of test cases by setting test scenario parameters， but the purely combinatorial parameter cannot effectively generate corner cases. In this paper， we present a novel approach to generating corner cases in a virtual environment for validation of a CNN （Convolutional Neural Network）-based lane detection function. We represent the scene features with parameters， and then use the deep Q-learning reinforcement learning approach to generate the parameter combinations of corner cases. In addition， by comparing with the approaches of random combination and pairwise combination of scene parameters， our approach can generate corner cases more efficiently and improve the testing efficiency of the autonomous driving perception functions.

Abstract:A path tracking method of intelligent vehicle based on stochastic model predictive control is proposed. The predicted trajectories of surrounding dynamic vehicles are characterized by positional uncertainty using a prime motion model and Gaussian distribution in the road coordinate system， and described using chance constraints in stochastic model predictive control （SMPC） as a way to establish constraints on the spatial location of the vehicles. The initial control sequence based on the kinematic model is obtained by means of a variable step size solution. Based on this initial solution， a stability constraint based on the relationship between the angular velocity of the transverse pendulum and the lateral eccentricity of the center of mass is introduced by considering the vehicle dynamics information to solve the optimal control volume. The effectiveness and stability of the proposed method are verified by simulation tests under various operating conditions.

Abstract:Although the autonomous valet parking technology is able to complete parking operations instead of drivers， the lack of scheduling of multiple vehicles can easily cause traffic chaos. This paper proposes a multi-attribute decision-based global planning method for multi-vehicle autonomous parking paths， which aims to solve the problem of unreasonable parking space allocation and reduce the overall cost of parking. First， a topological map of parking spaces is established to construct guided paths based on straight lines and clothoids. Then， the criteria and sub-criteria of the guided path selection are designed， and an analysis hierarchical process （AHP） path selection system is constructed to determine the optimal parking space and its guided path. Finally， the parking starting and ending positions are determined， and the parking path is calculated based on the collision constraints of the parking space using the clothoids as the reference. The scenario of multiple vehicles entering the parking lot at the same time is simulated， and the simulation results show that the method can effectively reduce the parking cost and improve the parking efficiency.

Abstract:Considering the uncertainties of actuator delays in a vehicle platoon， a novel connected cruise control based on robust model predictive control method is proposed. The approach deals with the safety constraints in transients， and accommodates vehicle platoons string stability and robustness against uncertain actuator delays. The mathematical model of a connected vehicle platoon is established and its control architecture for platoon cruising is proposed. Then， the linear feedback characteristics of model predictive control （MPC） under unconstrained conditions are analyzed. Adopting H∞ control method， the robustness to the uncertainties of actuator delays is analyzed， and the realization conditions of L2 string stability are obtained. Finally， a controller matching approach is applied to tune the weight matrix of MPC according to the linear feedback law obtained. The simulation results show that the proposed control method simplifies the controller matching in engineering applications and further improves the functional stability and safety of the connected cruise control for vehicle platoon.

Abstract:When automated manual transmission （AMT） vehicles are driving under the low vehicle speed， its tracking performance is of great importance for vehicle safety. This paper adopts a triple-step method to control the clutch slip process accurately， so as to ensure the speed tracking performance of AMT vehicles under low speed cruise scenario. The triple-step method makes full use of the feedforward information of the reference tracking trajectory and the feedback of the vehicle speed. The Lyapunov method is used during the control law deduction， so that the asymptotic stability of the control scheme is guaranteed. Eventually， the effectiveness of the controller is evaluated through the simulation and real-car tests. The simulation and experimental results show that by using the proposed triple-step method， the vehicle speed tracking performance can be guaranteed under various working conditions.

Abstract:In the project UNICARagil， an ECU was developed that is part of the novel UNICARagil brain architecture［1］. The so-called brainstem was dedicated for safety-critical real-time control of a fully automated vehicle via a service-oriented architecture. This paper describes the hardware and basic software architecture of the device and points out some of the safety measures. The focus is on the MPSoC and OS configuration， the update process of the ECU， and the boot process. A system of fallback instances protects the ECU against critical errors in the bootloader， kernel or root file system， as well during the development process as in the field. Finally， this paper points out the functionality of the device in the vehicle context. In numerous publications in science and on social media， it presents the vehicle going over the proving ground with the brainstem as a central component.

Abstract:Group safety is an important part of intelligent connected vehicle research in the vehicle-infrastructure cooperation environment. In the intersection area with strong structure and weak rule characteristics， the group safety characterization of vehicle driving can improve the safety of the intersection area. Firstly， the vehicle potential field model is constructed based on potential field theory， and the safety generalized characterization of individual vehicle driving behaviors in the intersection area is represented by boundary potential energy， vehicle potential energy， and speed potential energy； then the parameters and boundary range of group vehicle safety characteristics in the intersection area are constructed based on contour distribution characteristics of the potential energy field density； finally， through the simulation of natural driving data， the results indicate that the threshold value of the safety potential energy of the vehicle group in the straight forward， left turn， right turn scenarios is 2500， and the periodic change law of group safety potential energy is consistent with the phase change law of traffic signals， indicating that the model can accurately represent the behavior and safety state of the intersection vehicles， thus verifying the correctness and effectiveness of the intersection vehicle group safety model.

Abstract:Battery-powered electric vehicles have arrived on the streets. Most electric vehicles have to be recharged by plugging-in a cable. A wireless charging system with induction makes the process more comfortable. The primary coil， build in the parking lot， transforms the electric energy into field energy. The secondary coil， build in the vehicle， receives the energy and transforms it into electric energy and recharges the battery. To ensure safe and efficient charging， the coil pair must be coupled sufficient. This is done by positioning the vehicle well enough over the primary coil.This paper presents a simple and cost-effective way to verify whether the coupling between the coil pair is sufficient enough for charging. A resistor， on the secondary side， simulates the load of the battery on the wireless charging system in defined operating condition. The voltage across the resistor can be used to estimate the coupling between the coils. This relates to the positioning of the vehicle. The paper explains the concept on the basis of mathematical and physical principles. The results are evaluated on a real wireless power transmission track.

Abstract:The electrification of vehicle fleets for urban delivery transport is becoming increasingly important due to ever stricter legislation and the high social pressure on companies. In this paper， a converted 3.5 t light-duty vehicle with a maximum gross weight of 7.5 t is introduced. The vehicle has a serial hybrid electric powertrain with a maximum electric traction power of 150 kW and a 60 kW fuel cell range extender. The vehicle uses a 46 kW·h battery with a 400 V mean voltage level， resulting in a full electric range of 120 km. The electric drive is realized with an induction motor and a lithium-manganese-iron-phosphate （LMFP）-battery as well as a 2-speed gearbox. The fuel cell system has a fuel tank with a 95 L volume and 700 bar pressure level， which enables an overall vehicle range of 400 km. A proton-exchange membrane （PEM）， for direct hydrogen application， with a rated power of 1.0 W / cm2 is used. The PEM is integrated in a 60 kW fuel cell system for on-board energy generation on the vehicle. For the air-path the fuel cell system has an electrically assisted turbocharger to use the enthalpy of the exhaust air. The humidification of the intake air is realized with a water injector that uses water from dehumidification of the exhaust air. The hydrogen path is realized with an ejector circuit and a purge-valve for nitrogen disposal. In this paper， the design and control of the fuel cell system is introduced. Finally， the most important effects during the operation of the fuel cell system are presented.

Abstract:Pure electric vehicle equipped with two-speed gearbox has a better drivability and economy performance. Due to the simplified structure and no torque interruption during the gear shift process， the configuration that combines friction clutch for high gear and one-way clutch for low gear has become the mainstream scheme of two gear transmission of electric vehicles. However， when the vehicle is driving in reverse gear， the dog clutch should be engaged to overcome the problem that the one-way clutch can only transmit torque in one direction. A novel two-speed automatic transmission （I-AMT） without power interruption based on dog clutch is taken as the research object， and the synergistic control of power motor and reversing actuator motor make the dog clutch act smoothly and quickly. To address the response delay problem of the power motor， the Smith estimator algorithm is used to estimate and compensate the control system. The control strategy is verified by experiments， and the results show that the control strategy can effectively avoid the vehicle jerk when the jaw clutch is engaged， which ensures the smooth gear shift of the transmission in a short time.

Abstract:Electric machines are replacing increasingly combustion engines as traction machine in modern vehicles. To monitor the behavior of the electric machines， sensors are needed. A major challenge is the electrical powering of the sensors on rotating parts of the machine. By using an energy harvester， parasitic energy from the electric machine， such as electromagnetic and kinetic， can be collected. The collected energy gets transformed into electric energy and used to power sensors. Additionally， a storage device can be integrated. To realize an energy harvester， a transverse flux machine has been investigated， focusing on the rotor of the machine. The goal for the energy harvester is to collect enough energy to power a temperature sensor with contactless data transfers via Bluetooth Low Energy. Therefore， the amount of energy that can be expected to be collected during operation and production when positioning the energy harvester on the rotor of the transverse flux machine is calculated.

Abstract:Autonomous driving， digitalization， and electromobility have greatly increased the number of functions in vehicles in recent years. This trend will continue in the coming years. An extension of functions is often associated with an increase in the quantity of wires. However， for energy-efficient and thus sustainable mobility， developers need to keep the vehicle weight as low as possible. Likewise， the minimization of costs must be strived for. For this purpose， an algorithm is necessary， which designs the wiring under the specification of component positions. We took into account various constraints with regard to packaging， temperature load， and ease of assembly aspects. In addition， the routing can be controlled by desired preferences， e.g. more wires along the center of the vehicle than on the outside in the direction of the vehicle's longitudinal axis. The specification of cable lengths， diameters as well as the exact routing are the results. Previous approaches usually consider only partial aspects， no 3D structure， and only a few number of constraints.

Abstract:Driver assistance systems are designed not only to support the drivers in their general driving activities but also to be able to take over in critical situations， too. Test drives with a prototype vehicle are the most realistic way to test these systems. The test drive exposes the systems to all kinds of environmental influences and examines their reliability. Since test drives with prototypes are very costly and difficult to reproduce in the exact same way， hardware-in-the-loop （HiL） test benches are often used in the development and testing process. HiL test benches providing the relevant hardware and can also provide simulated environmental influences for these systems under test （SUT）. During test drives with real vehicles， variations in the electrical system voltage occur due to the different environmental influences. These variations are based on changing electrical loads. Currently these variations in the vehicle electrical system voltage cannot be simulated on HiL test benches. In order to identify causes and underlying phenomena of the variations， recorded data from real test drives are examined with respect to possible phenomena. These results are then used to derive a phenomenological stimulation that can be used to simulate realistic voltage curves on test benches. The paper analysis vehicle measurements with the aim of finding possible causes for the long and short-therm change of the on-board voltage. This paper presents an approach for realistic stimulation of voltage variations in the context of virtual test drives on HiL test benches.

Abstract:Proton exchange membrane fuel cell vehicles are an important technology route to achieve carbon neutrality in transportation. In this paper， a system controller was developed for high efficiency and long durability on an integrated 100 kW passenger car fuel cell system. The complete control program is developed in conjunction with Matlab/Simulink and the Motohawk rapid control prototype. Then， the closed-loop control performance of the controller was discussed， represented by the air subsystem. Finally， with the implementation of the FC controller developed， the dynamic performance of the entire system was studied. The results show that the FC system has an excellent potential in terms of net power， system efficiency， and consistency. The maximum efficiency of the system reaches 62%， and the voltage variation coefficient （Cv） is controlled below 1% during dynamic load changes.

Abstract:In this paper， A sixth-order model of air supply system of a proton exchange membrane fuel cell （PEMFC） was established. PID control and linear quadratic regulator （LQR） control were combined with neural network feedforward control to form two composite control strategies respectively， and the response and stability of the oxygen excess ratio （OER） during variable load were compared under two composite control strategies. In the design of the LQR controller， the model was first linearized through a single equilibrium point to obtain the state feedback gain and the reduced-order state observer gain. Simulation results show that the composite control strategy combining neural network feedforward and LQR is significantly better than the other control strategies in the full range of operating conditions， subject to linearization of the single equilibrium point. Aiming at the situation that the control effect was degraded in the working condition far away from the equilibrium point， the method of multi-equilibrium point linearization was further adopted to optimize the design of the LQR controller to dynamically adjust the corresponding gain. The results show that the multi-equilibrium points LQR control method exhibits the best rapid response and stability in OER control.

Abstract:Fuel cell shutdown purge is an important method to improve the success rate of cold start. In this paper， a two-dimensional transient proton exchange membrane fuel cell （PEMFC） model is established to study the shutdown purge process of PEMFC under the hydrogen air purge strategy. Based on the GDL real pore model， PEMFC related conservation equation and ionomer gas phase transfer equation， the influence of the different humidity of purge gases on the purge speed and the membrane-bound water content after the purge， and the influence of the real pore structure of GDL on the internal mass transfer phenomenon of GDL during the shutdown purge stage were studied. The results show that the decrease in humidity of purge gas can effectively promote the gas phase transfer of membrane-bound water during the shutdown blowing process， thereby reducing the final water content； the real pore structure can provide a more realistic explanation of the transfer rule of water and gas during purge.

Abstract:Electricity-based synthetic fuels （E-Fuels） represent an important building block for achieving ambitious environmental and climate targets. The C1 group oxygenates are due to clean combustion properties particularly attractive， including oxymethylene ether （OME）， dimethyl carbonate （DMC） and methyl formate （MeFo）. In order to fully explore the potential of new fuels in internal combustion engines， the gasoline and diesel combustion and emission models were optimized and extended. After successful implementation， validation and calibration of the models， investigations are carried out on virtual test vehicles. These focus on efficiency potential， emission formation and economy. In the first step， different engine concepts of OME and DMC/MeFo are developed， each based on modern gasoline， diesel and CNG engines. In the second step， these engine concepts are evaluated for an E-Class passenger car and a 40-ton truck in virtual real driving cycles （RDE）. It can be shown that the OME engine realizes the best efficiency and at the same time minimal emissions through adapted injection strategy and intelligent exhaust gas recirculation （EGR）. The blended fuel DMC/MeFo represents great efficiency potential thanks to high knock resistance with state-of-the-art engine technologies. The dedicated DMC/MeFo engines approaches the efficiency of diesel engine concepts with significantly less engine complexity， making DMC/MeFo a promising prospect for heavy-duty application.

Abstract:As a relatively important component in the body design， the DC brush motor can easily generate electromagnetic interference with other on-board electrical appliances， causing certain hidden dangers to the safe driving of the car. Aiming at the modeling and prediction of the electromagnetic interference of the brushed DC motor， through in-depth research on the commutation process of the brushed DC motor， the motor conduction interference system model and the equivalent circuit model of the motor winding， the power supply and LISN （Line Impedance Stabilization Networks） are established. The effective circuit model is used to simulate and predict the conducted interference intensity of the motor， and the results are more accurate； based on the test process of the motor radiated interference， the CST software is used to establish a 3D model of the radiated interference of the motor， and the 3D model and the 2D model are co-simulated， using the current The excitation source in the frequency domain is obtained from the clamp test， and the transfer function of the radiation interference system is obtained by the CST simulation， and the model simulation prediction of the radiation interference intensity of the motor is carried out， and the results are relatively accurate.

Abstract:Considering safety requirements while developing electrical and electronic （E/E） architectures is a prerequisite for the realization of future technologies such as autonomous driving. Following the ISO 26262 standard， safety analyses have to be conducted in the early phase of the development lifecycle in order to detect design flaws and take actions to improve the design. This paper presents a model-based approach for addressing safety requirements conforming to ISO 26262 during the design phase of automotive E/E architectures. Based on the requirements， a set of safety-related constraints is extracted， which can be used in an integer linear programming （ILP） model to optimize E/E architectures.

Abstract:Transition metal oxides are considered as potential catalysts for hydrogen production in alkaline water electrolysis due to their low cost， easy fabrication， and excellent electrochemical properties. But the investigation of their morphology on catalyst performance is insufficient. In this paper， multi-dimensional （one-dimensional （1D）， two-dimensional （2D）） gear-shaped transition metal oxide catalysts （NF/NCFO-g） are designed and used as bifunctional electrocatalysts for hydrogen production. In the 1 M KOH solution and a 100 mA cm-2 current density， NF/NCFO-g exhibited anodic overpotential of 0.23 V and a cathodic overpotential of 0.29 V， as well as Tafel slopes of 196 （anodic） and 233 mV dec-1 （cathode）， which are superior to both 1D （NF/NCFO-n） and 2D （NF/NCFO-s） catalysts. The synergistic effect between the “apical advantage” of the 1D nanoneedle and the surface charge effect of the 2D sheet structure are responsible for the excellent electrocatalytic performance of NF/NCFO-g. The “apical advantage” causes a large amount of charge to accumulate at the tip， rendering the inner layer capacitance width being reduced， while the surface charge of 2D sheet structure helps form more oxygen vacancy active sites， resulting in an optimized reaction energy of the transition state. In addition， at high current densities， the 1D nanoneedle structure enhances hydrophilicity and reduces the bubble radius， thus accelerating the bubbles release.