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Aimed to more truly and stably measure the fuel economy of a vehicle under different driving cycles, simultaneously reduce prime cost and short experimental period. An engine fuel economy test method and bench which could adapt to multiple cycle conditions was developed. The fuel economy test of a certain SUV under NEDC/WLTC was carried out, and the transient operating parameters of the engine were collected. The engine fuel economy test bench was established and accurately controlled according to transient parameters. The FEI of five different formulations of engine oils was tested. The results indicate that the actual bench parameters are in good agreement with the target transient parameters. Multiple FC measurements of baseline oil and multiple FEI measurements of high reference oil show that the engine bench has good repeatability. The data fluctuation degree of bench test is obviously smaller than that of vehicle test. The correlation coefficients of comprehensive FEI between bench test and vehicle test are 95.25% (NEDC) and 96.39% (WLTC). It means that the bench test can completely replace the vehicle test for fuel economy analysis. The FEI of No.3 oil which has the best fuel improvement are 1.888% (NEDC) and 1.248% (WLTC) respectively. Compared with the vehicle test, the engine bench testing can save 75% of the time. The fuel economy bench and test methods are also suitable for the verification of fuel economy improvement of other engine optimization measures under different driving cycles. The development period of engine technologies can be shortened, and the test cost can be reduced. [ABSTRACT FROM AUTHOR]

Under unstable wind loads, the wind turbine tower, as a supporting component of the horizontal axis experiences inevitable vibration. To explore the vibration characteristics of the tower, a vehicle test platform is established to measure the vibration acceleration component signals at different heights of a 300W small horizontal axis wind turbine tower. The results show that specific vehicle vibration test equipment can accurately test the vibration characteristics and laws of small wind turbine towers. The main vibration form of the tower is low frequency, with noticeable axial vibration at the top and lateral vibration in the middle of the tower due to aerodynamic load from natural wind. These findings can be used as a valuable reference for the safety and reliability design of the whole machine and the low-frequency vibration status monitoring of wind turbines. [ABSTRACT FROM AUTHOR]

The thermal system is one of the most critical parts of electric vehicles since its performance directly affects the vehicle's energy consumption and emissions. The current digital twin technology in the auto industry lacks a thermodynamic model focusing on energy consumption, and the control strategy lacks an adversary model, which does not allow for an in-depth discussion of energy consumption without sufficient use of data. This paper aims to study the optimization of the thermal system coupled energy flow in electric vehicles with digital twin technologies. The vehicle thermal management digital twin technology discussed in this paper establishes the digital twin model of the vehicle thermodynamic system that focuses on energy consumption. Meanwhile, vehicle energy flow experiments are carried out to analyze the energy consumption of key components under typical high energy consumption conditions. Accordingly, this research optimizes the control logic to optimize energy consumption and enhance vehicle ranges without changing the hardware architecture. The results show that after the optimization of the control strategy, the electricity consumption under high-temperature, low-temperature, and dehumidification conditions is reduced by 890 W, 456 W, and 1594.9 W, respectively. The vehicle driving mileages are increased by 12.51 km, 6.16 km, and 22.42 km, respectively.

(1) Background: After motion sickness occurs in the ride process, this can easily cause passengers to have a poor mental state, cold sweats, nausea, and even vomiting symptoms. This study proposes to establish an association model between motion sickness level (MSL) and cerebral blood oxygen signals during a ride. (2) Methods: A riding simulation platform and the functional near-infrared spectroscopy (fNIRS) technology are utilized to monitor the cerebral blood oxygen signals of subjects in a riding simulation experiment. The subjects' scores on the Fast Motion sickness Scale (FMS) are determined every minute during the experiment as the dependent variable to manifest the change in MSL. The Bayesian ridge regression (BRR) algorithm is applied to construct an assessment model of MSL during riding. The score of the Graybiel scale is adopted to preliminarily verify the effectiveness of the MSL evaluation model. Finally, a real vehicle test is developed, and two driving modes are selected in random road conditions to carry out a control test. (3) Results: The predicted MSL in the comfortable mode is significantly less than the MSL value in the normal mode, which is in line with expectations. (4) Conclusions: Changes in cerebral blood oxygen signals have a huge correlation with MSL. The MSL evaluation model proposed in this study has a guiding significance for the early warning and prevention of motion sickness. [ABSTRACT FROM AUTHOR]

The fuel economy and ride comfort of range-extender electric vehicles are closely related to the adopted energy management strategy (EMS). The appropriate EMS with noise constraints can not only effectively reduce fuel consumption, but improve ride comfort during vehicle travel. To this end, an EMS was proposed in this paper in which an adaptive equivalent consumption minimization method was developed considering the noise level in the driving cabin based on vehicle speed feature recognition so that the vehicle fuel economy and ride comfort can be optimized simultaneously through a calibratable cost function. The linear state of charge reference trajectory based on the route information, which could be obtained by a mileage-indication knob equipped in the cockpit, was employed to determine the start-stop of the range-extender. The proposed strategy was verified on the road in a light-duty range-extender electric van. The results were compared with those obtained from the conventional equivalent consumption minimization strategy and a dynamic equivalent consumption minimization strategy. The experimental results indicated that the proposed strategy could reduce the vehicle fuel consumption by 3.28 % and 1.40 %, respectively, on an urban-suburban integrated route. Moreover, the ride comfort indicated by the noise level in the driving cabin was better as well. [ABSTRACT FROM AUTHOR]

The concern over safety features in autonomous vehicles is increasing due to the rapid development and increasing use of autonomous driving technology. The safety evaluations performed for an autonomous driving system cannot depend only on existing safety verification methods, due to the lack of scenario reproducibility and the dynamic characteristics of the vehicle. Vehicle-In-the-Loop Simulation (VILS) utilizes both real vehicles and virtual simulations for the driving environment to overcome these drawbacks and is a suitable candidate for ensuring reproducibility. However, there may be differences between the behavior of the vehicle in the VILS and vehicle tests due to the implementation level of the virtual environment. This study proposes a novel VILS system that displays consistency with the vehicle tests. The proposed VILS system comprises virtual road generation, synchronization, virtual traffic manager generation, and perception sensor modeling, and implements a virtual driving environment similar to the vehicle test environment. Additionally, the effectiveness of the proposed VILS system and its consistency with the vehicle test is demonstrated using various verification methods. The proposed VILS system can be applied to various speeds, road types, and surrounding environments. [ABSTRACT FROM AUTHOR]

Due to the limited features and poor accuracy of current methods for predicting the dynamic response of subgrades, this paper proposes an innovative approach that combines subgrade dynamic response field tests and machine learning (ML) technology. This method uses Bayesian optimization XGBoost (BO-XGBoost), Bayesian optimization LightGBM (BO-LightGBM), and Bayesian optimization CatBoost (BO-CatBoost) models to analyze the effects of physical properties and stress conditions on the dynamic stress, dynamic acceleration, and dynamic displacement of the subgrade. The optimal ML model was selected on the basis of the residuals, coefficient of determination (R 2), mean squared error (MSE), and mean absolute error of the prediction results. Using SHapley additive exPlanations (SHAP), the global importance, feature importance, and feature interaction behaviours of the optimal ML model input features were explained, and the main controlling features affecting the dynamic stress, dynamic acceleration, and dynamic displacement of the subgrade were obtained. The research results indicate that the prediction results of the BO-XGBoost, BO-LightGBM, and BO-CatBoost models for dynamic stress, dynamic acceleration, and dynamic displacement are mostly within the 10 % error range, and the R 2 values of these three models are greater than 0.98. On the basis of the comparison results of the hyperparameter combinations, the objective of MSE (MSE obj), and the error evaluation metrics, the BO-CatBoost model yields the highest prediction accuracy, making it the optimal ML prediction model. This prediction method can quickly and intelligently obtain the main controlling features of dynamic stress, dynamic acceleration, and dynamic displacement, including depth (H), axle load (P), frequency (f), and moisture content (w). The boundary conditions for these four features are as follows: H > −1.3 m, P > 10 ton, f > 3.7 Hz, and w >18.1 %. The research results contribute to enhancing the service performance and lifespan of expressways. • The optimal hyperparameters of the machine learning models are found by Bayesian optimization. • The BO-CatBoost model effectively predicts the dynamic response of lateritic soil subgrade. • The BO-CatBoost model is effectively explained by SHAP. • The main influencing features of the dynamic response of lateritic soil subgrade are revealed. [ABSTRACT FROM AUTHOR]

It is difficult to accurately simulate the cornering performance of a vehicle using a simplified vehicle model; therefore, a proper evaluation process should be conducted from an experimental perspective. In addition, there are several possible combinations of subparts in suspension modules, such as springs, dampers, stabilizers, or other parts, and the characteristic identification of each part may require significant costs and time. In this study, the cornering performance of a vehicle system was experimentally evaluated using several combinations of subparts in the suspension module as well as candidate tire cases. All characteristic parameters used in the two indices were previously identified as separate steps, and vehicle tests were performed according to all the required test scenarios for cornering performance. The evaluation of the cornering performance of a vehicle was proposed using the suspension characteristic cornering performance (SCCP) index and suspension and tire characteristic cornering performance based-on-tests (STCT) index, respectively, using measured data from a vehicle test. The STCT index is revised from the SCCP index by considering the tires' effects, and the optimal selection of the suspension and tires can be obtained from the proposed indices. The feasibility of the proposed STCT index was verified by evaluating the cornering performance from all the prepared test results. [ABSTRACT FROM AUTHOR]

Aiming at the problem of traditional brake-by-wire systems that lack adaptive identification of vehicle feature information and the number of hardware module connections, the effect of brake-by-wire system with self-recognition functions were studied, including multiple pressure regulating valves, wheel speed sensors, steering angle sensors. The central control unit automatically was used to recognized the connection status of the hardware components of the brake system through the central control unit, so that an appropriate working mode could be selected by the brake system, and the speed of vehicles was set to 40 km/ h on roads with adhesion rates of 0. 8 and 0. 4 respectively. The experiments could be divided into three parts, which were the detection whether the trailer is connected to the tractor, identification of the wheel speed sensor and pressure adjustment module on the drive shaft, and identification of the steering angle sensor and yaw rate sensor. The results show that when the emergency braking is touched off, the connection status of the wheel speed sensor, pressure adjustment module, steering angle sensor and other hardware can be detected through the CAN bus using the central control unit. The CAN communication signal is fed back to the brake master valve to provide effective braking force for the vehicle, and the system's adjustment ability on high-adhesion roads is better than its performance on low-adhesion roads. [ABSTRACT FROM AUTHOR]

This paper aims at investigating the combined effects of wetting and traffic loading on the dynamic response of lateritic soil subgrade in the southern region of China. Vehicle tests involving four axle loads of trucks travelling at four speeds and vibration tests involving six repetitive vibration loadings were carried out in a test section of the Nanning–Zhanjiang expressway under three types of wetting conditions. The effects of wetting, vehicle speed, moving load, repeated loading, and loading numbers on the dynamic stress, dynamic acceleration, dynamic displacement, and accumulative deformation of the subgrade are investigated. The results show that under the effect of wetting, the dynamic response generated by the moving load on the subgrade increases, and excessive moving loads increase the dynamic response of the subgrade. The dynamic response of the subgrade exhibited exponential attenuation along the depth direction and transverse direction, and the influence depths were 2.3 m and 3.3 m for axle loads of 7 t and 30 t, respectively. At a depth of 0.3 m from the subgrade surface, the time – domain curves of the dynamic stresses are a double hump. The accumulative deformation rapidly increased and then gradually stabilized. When the loading was 3 million cycles, the accumulative deformation at the wetted twice stage was 16.8 % and 35.2 % greater than that at the wetted once and unwetted stages, respectively. The research results provide a reference for the structural design and safe operation of expressway subgrades in lateritic soil areas. • The effects of the varying moisture content and moving loads on the dynamic response of the lateritic soil subgrade along the depth and transverse directions are revealed. • The effects of the varying moisture content and repeated loading on the accumulative deformation of the lateritic soil subgrade are investigated. • The time-domain characteristics of the varying moisture content on the dynamic stresses and dynamic accelerations along the depth direction are concluded. [ABSTRACT FROM AUTHOR]

(1) Background: After motion sickness occurs in the ride process, this can easily cause passengers to have a poor mental state, cold sweats, nausea, and even vomiting symptoms. This study proposes to establish an association model between motion sickness level (MSL) and cerebral blood oxygen signals during a ride. (2) Methods: A riding simulation platform and the functional near-infrared spectroscopy (fNIRS) technology are utilized to monitor the cerebral blood oxygen signals of subjects in a riding simulation experiment. The subjects’ scores on the Fast Motion sickness Scale (FMS) are determined every minute during the experiment as the dependent variable to manifest the change in MSL. The Bayesian ridge regression (BRR) algorithm is applied to construct an assessment model of MSL during riding. The score of the Graybiel scale is adopted to preliminarily verify the effectiveness of the MSL evaluation model. Finally, a real vehicle test is developed, and two driving modes are selected in random road conditions to carry out a control test. (3) Results: The predicted MSL in the comfortable mode is significantly less than the MSL value in the normal mode, which is in line with expectations. (4) Conclusions: Changes in cerebral blood oxygen signals have a huge correlation with MSL. The MSL evaluation model proposed in this study has a guiding significance for the early warning and prevention of motion sickness.

Barium (Ba) has been widely and successfully added to three‐way catalysts to effectively control gasoline vehicle emissions. While the introduction of Ba is well‐known to have a very significant impact on three‐way catalysis (TWC) performance, the role of Ba under practical TWC conditions remains insufficiently understood. In this study, we investigated the role of Ba in a Pd‐based catalyst in a standard TWC process using a gasoline vehicle and in situ/operando infrared (IR) spectroscopy. The addition of Ba was found to reduce all of the emissions considered (NOx, CO, and non‐methane hydrocarbons) in the vehicle exhaust gas; it also suppressed supported‐metal aggregation, which is a requirement of a high‐performance catalyst. In addition, IR studies using model powder catalysts revealed that the efficient formation of intermediate surface nitrate species and their subsequent reactions with reductant gases, such as CO, H2, and C3H6 (as a hydrocarbon), play key roles in reducing emissions. This process is akin to the NOx storage and reduction (NSR) mechanism commonly used to control diesel emissions. [ABSTRACT FROM AUTHOR]

The zirconia solid electrolyte SOFC (solid oxide fuel cell) has the characteristics of oxygen ion conduction function, high-temperature resistance, thermoelectric coupling effect, etc. A NOx sensor based on zirconia solid electrolyte has common characteristics and problems with the SOFC in principle and application. The research objective of this paper is to solve the application problems of smart NOx sensors in diesel vehicles or gasoline vehicles. Improvements in the application performance of the NOx sensor can help the NOx emissions of gasoline vehicles or diesel vehicles better meet the requirements of emission regulations. The smart NOx sensor is a regulatory sensor required by vehicles for China's Phase VI Vehicle Exhaust Emission Regulations or Euro Phase VI Vehicle Exhaust Emission Regulations. The smart NOx sensor is a key sensor device for improving fuel efficiency and reducing pollution. Moreover, its measurement performance includes dynamic immunity to interference, response speed, and measurement accuracy, which are key factors affecting vehicle emissions. This paper focuses on the impact of the physical structure, electrode characteristics, and control strategies of the sensor on its performance during the application. An excellent sensor structure, electrode structure, and control strategy are given based on application analysis and experimental testing. The results show that the application performance of this smart NOx sensor meets the requirements of exhaust aftertreatment systems. [ABSTRACT FROM AUTHOR]

It is difficult to accurately simulate the cornering performance of a vehicle using a simplified vehicle model; therefore, a proper evaluation process should be conducted from an experimental perspective. In addition, there are several possible combinations of subparts in suspension modules, such as springs, dampers, stabilizers, or other parts, and the characteristic identification of each part may require significant costs and time. In this study, the cornering performance of a vehicle system was experimentally evaluated using several combinations of subparts in the suspension module as well as candidate tire cases. All characteristic parameters used in the two indices were previously identified as separate steps, and vehicle tests were performed according to all the required test scenarios for cornering performance. The evaluation of the cornering performance of a vehicle was proposed using the suspension characteristic cornering performance (SCCP) index and suspension and tire characteristic cornering performance based-on-tests (STCT) index, respectively, using measured data from a vehicle test. The STCT index is revised from the SCCP index by considering the tires’ effects, and the optimal selection of the suspension and tires can be obtained from the proposed indices. The feasibility of the proposed STCT index was verified by evaluating the cornering performance from all the prepared test results.

Metro vehicles have always been known for their high passenger density, frequent traffic flow and strong alternating loads due to their severe running environment. As the major support component, the bogie frame suffers from fatigue damages and receives a high intensity of interest. In this work, a theoretical model is presented between the measured strain and the structural stress via multiple load identification, wherein recognition matrices and stress evaluations of the bogie frame are defined according to the locations found in finite element analysis (FEA). The model is validated through random loading in FE simulation, and the load deviation is within 1.1 kN. A vehicle experiment was performed on the second bogie of the head car on a six-car metro train. The signed von Mises (SVM) stress was calculated at critical locations with the proposed method and compared with what was measured. The excessive part was no more than 14.97%, comparing the reconstructed with the measured amounts. Stress spectra were developed utilizing rain-flow counting and evaluated in terms of the damage accumulation rule with the optimal spectra groups determined from convergence analysis. The evaluation indicates that, when the running mileage increases to the full life cycle of 3,960,000 km, the maximum equivalent damage reaches 0.35 and 0.46 at the gear box base for measured and reconstructed amounts, respectively. Research outcomes suggest that the proposed method offers an alternative for fatigue assessment and maintenance strategies on metro vehicles, as well as other types of rail-transit vehicles.

To comprehensively investigate the energy distribution and performance of a battery electric vehicle (BEV), an integrated simulation model based on energy flow test data was developed and validated, and the energy flow characteristics of the BEV throughout the entire driving range in low-temperature conditions were studied. The results show that the battery heat loss and motor energy loss first increase and then decrease with an increment in cycle number, while the transmission loss first decreases and then remains constant. The energy recovery efficiency demonstrates an incremental trend with the number of cycles post-battery charging, while the energy utilization efficiency experiences a decline due to escalating energy losses within the power distribution unit (PDU). The energy flow characteristics of the BEV exhibit a pronounced connection with the speed properties inherent in the driving cycle. The battery charge energy is maximal under Urban Dynamometer Driving Schedule (UDDS), whereas the electricity consumption per 100 km is minimized under China light-duty vehicle test cycle-passenger (CLTC-P). Conversely, the energy utilization and recovery efficiency are the highest under Worldwide Light-duty Test Cycle (WLTC). These findings provide directional insights, theoretical support and data basis for rational performance evaluation and optimal energy distribution of BEVs. [Display omitted] • Energy flow tests for a BEV were conducted in low-temperature conditions. • The integrated simulation model for the BEV was developed and validated. • Energy utilization efficiency decreased with cycles due to the increasing PDU loss. • Vehicle energy flows over entire driving range were related to speed properties. [ABSTRACT FROM AUTHOR]

The zirconia solid electrolyte SOFC (solid oxide fuel cell) has the characteristics of oxygen ion conduction function, high-temperature resistance, thermoelectric coupling effect, etc. A NOx sensor based on zirconia solid electrolyte has common characteristics and problems with the SOFC in principle and application. The research objective of this paper is to solve the application problems of smart NOx sensors in diesel vehicles or gasoline vehicles. Improvements in the application performance of the NOx sensor can help the NOx emissions of gasoline vehicles or diesel vehicles better meet the requirements of emission regulations. The smart NOx sensor is a regulatory sensor required by vehicles for China’s Phase VI Vehicle Exhaust Emission Regulations or Euro Phase VI Vehicle Exhaust Emission Regulations. The smart NOx sensor is a key sensor device for improving fuel efficiency and reducing pollution. Moreover, its measurement performance includes dynamic immunity to interference, response speed, and measurement accuracy, which are key factors affecting vehicle emissions. This paper focuses on the impact of the physical structure, electrode characteristics, and control strategies of the sensor on its performance during the application. An excellent sensor structure, electrode structure, and control strategy are given based on application analysis and experimental testing. The results show that the application performance of this smart NOx sensor meets the requirements of exhaust aftertreatment systems.

For fuel cell hybrid vehicles, the energy distribution mechanism of the fuel cell and power battery should reasonably allocate the power output of the fuel cell and power battery, optimize the efficiency of both and control the power battery SOC to fluctuate within a reasonable range. To test the energy flow and operation characteristics of the powertrain of two hybrid car models on the market, two test vehicles (called vehicle A and vehicle B in this paper) are tested on an AIP 4WD chassis dynamometer under constant power and the China Light-Duty Vehicle Test Cycle-Passenger cycle condition, respectively. The test results show that vehicle A has a smaller power battery SOC variation interval and a lower variable rate than vehicle B. The cumulative power battery output energy of vehicle B is more significant than that of vehicle A. More importantly, the current rare public test reports of fuel cell vehicles make this study very valuable. This paper has important reference significance for the energy flow characteristics and energy management strategy of existing fuel cell hybrid vehicles.

Real-time monitoring of overturning coefficients is very important for ensuring the safety of high-speed trains passing through complex terrain sections under strong wind conditions. In recent years, the phenomenon of "car swaying" that occurs when trains pass through the complex terrain has brought new challenges to ensuring the safety and riding comfort of passengers. In China, more and more high-speed trains are facing strong wind environments when running in complex terrain sections. However, due to the limitation of objective conditions, so far, only a few economical and effective methods of measurement have been developed that are suitable for real-time monitoring of the overturning coefficient of commercial vehicles. Therefore, considering the applicability and universality of such a monitoring method, this study presents a method for measuring the overturning coefficient of trains using the primary suspension system under strong winds. A vehicle test was carried out to verify the accuracy of the method. The results show that after correction, the overturning coefficient obtained from the primary suspension system is generally consistent with the overturning coefficient obtained from the instrumented wheelset. The method of measuring the overturning coefficient of trains in strong wind environments with the primary suspension system is, thus, proven feasible. [ABSTRACT FROM AUTHOR]

Highlights • Chassis dynamometer tests for gasoline-powered vehicle were carried out under cold start and warm up NEDC. • The combustion rate of ICE in each stage under cold start and warmed up NEDC was compared. • The thermodynamics process of ICE under NEDC were disintegrated and then quantitatively analyzed. • Only in early stage ICE performance between cold start and warmed up NEDC differs obviously. • The EEE in the early stage of cold start NEDC decreases largely due to the lower EER. Abstract In this study, the chassis dynamometer tests for a gasoline-powered passenger vehicle were carried out under cold start and warm-up NEDC. The operating states, combustion and performance parameters of engine were measured continuously during vehicle driving cycles. Then, the combustion and thermodynamics processes under cold start and warm-up NEDC were compared and the influence factors for their differences were revealed. Results show that, since valve timing of tested engine is almost the same under cold start and warm-up conditions, it is not the main influence factor for the differences of in-cylinder RGF and EER. Although in-cylinder RGF decreases during cold start NEDC, the gap is too small to make any difference. Only in the early stage of NEDC, cold start has an obvious influence on in-cylinder combustion and thermodynamics processes of engine. For example, sparking timing is retarded, and SOC as well as 50% combustion position is further retarded. However, the heat transfer loss is also reduced due to the lower combustion temperature, thus the influence of later sparking timing on the indicated thermal efficiency of engine is restricted to some extent under cold start condition. All these provide theoretical guidance for improving engine actual performance. [ABSTRACT FROM AUTHOR]

For a vehicle engine, it usually operates under transient conditions, and the transient behaviors represent its actual performance. In order to improve the actual performance of GDI engine during vehicle driving cycles, the vehicle test was conducted under new European driving cycle (NEDC), and the thermodynamics, combustion and emission characteristics were tested. Then, the transient performance of GDI engine was compared with the steady-state behaviors. In this way, the differences in various performance parameters under NEDC and steady-state conditions were demonstrated, and the reasons were revealed. Results show that, the spark timing, start of combustion (SOC), ignition delay, 50% combustion location and 10–90% combustion duration of GDI engine under NEDC deviate from their steady-state values seriously especially at low load, resulting in the large combustion instability. The consistency of pumping mean effective pressure (PMEP) under NEDC and steady-state conditions is satisfactory, while the indicated thermal efficiency has a large fluctuation during NEDC, and in most cases it is lower than the steady-state values. Both the transient HC and CO emissions are larger than the steady-state values especially at low load, while the transient NOx emission during NEDC is less than the steady-state values. All those not only demonstrated the change rules of combustion and emission characteristics of GDI engine under NEDC, but also provided guidance for improving the actual performance of vehicle engine. [ABSTRACT FROM AUTHOR]

This paper describes lane change motion planning with a combination of probabilistic and deterministic prediction for automated driving under complex driving circumstances. The autonomous lane change should arrive safely at the destination. The subject vehicle needs to perceive and predict the behaviors of other vehicles with sensors. From the information of other vehicles, a collision probability is defined using a reachable set of uncertainty propagation. In addition, the lane change risk is monitored using predicted time-to-collision and safety distance to guarantee safety in lane change behavior. A safe driving envelope is defined as constraints based on the combinatorial prediction (probabilistic and deterministic) of the behavior of surrounding vehicles. To obtain the desired steering angle and longitudinal acceleration to maintain the automated driving vehicle under constraints, a stochastic model-predictive control problem is formulated. The proposed model has been evaluated by performing lane change simulations in MATLAB/Simulink, while considering the effect of combination prediction. Also, the proposed algorithm has been implemented on a test vehicle. The simulation and test results show that the proposed algorithm can handle complicated lane change scenarios, while guaranteeing safety. [ABSTRACT FROM AUTHOR]

In this study, the combustion and emission characteristics of a turbocharged GDI engine under cold start NEDC were investigated based on chassis dynamometer test. The operating states, combustion and emission performance of GDI engine were measured continuously during vehicle driving cycles. Then, the combustion and emission characteristics of GDI engine under cold start NEDC were obtained and the influence factors were revealed by synchronous analysis of various operating parameters. The results show that, the combustion duration from start of combustion (SOC) to 50% combustion location changes a little under cold start NEDC. At most time, the 10–90% combustion duration usually changes in the range of 20–40 °CA, which turns longer under idling conditions but shorter under acceleration conditions. Since the sparking timing is severely retarded in the beginning stages of NEDC, the effect of cold start on hydrocarbon (HC) emission is very limited. HC emission increases sharply under deceleration conditions, due to the decrease of engine indicated mean effective pressure (IMEP). Carbon monoxide (CO) emission does not seem to have relevance to the cold start condition, and it is very sensitive to excess air coefficient while the effects of other parameters are very little. Nitrogen oxide (NOx) emission increases under acceleration conditions but decreases under deceleration conditions, which is mainly influenced by the IMEP, then followed by engine speed. All those not only demonstrated the change rules of combustion and emission characteristics of turbocharged GDI engine under cold start NEDC, but also provided the guidance for improving the vehicle emission performance. [ABSTRACT FROM AUTHOR]

Aiming at the problems such as large volume of traditional shifter, layout position rigid, the impact of cab noise control because of increasing hole, and can not support intelligent parking, intelligent driving function development and implementation and other issues, the shift mechanism and rocker driving method were studied. The driver’s shift habits, shift strategy, fault diagnosis and limping were summarised, a wire shift control system based on dual 16-bit microcontroller was proposed. The electronic signal instead of the mechanical position signal was used to identify gear information, and motor-driven was used instead of the traditional mechanical zipper, can quickly identify the current vehicle and stall state, through the motor closed-loop control to achieve accurate shift and gear information display. The results indicate that the system eliminates the constraints of traditional mechanical parts and gearbox linkage, greatly improve the design freedom, can effectively reduce the mechanical wear and tear, reduce the complexity of parts. And the shift mechanism is flexible and responsive. [ABSTRACT FROM AUTHOR]

As growing demand of vehicle safety system, especially regarding intelligent transport systems (ITS), automotive manufacturers are focusing more on driving safety and efficient transportation for vehicle users. Many safety systems have been launched in the market recently so, it is important to evaluate the vehicle safety systems and ITS. The ITS based intelligent vehicle test bed was constructed to meet the growing demand of test and verification for such ADAS and ITS systems. First, this paper describes in detail concept of the test-bed. This test-bed is carefully designed to meet the requirements of ISO/TC204 standards. In order to verify the design of the test-bed, virtual test with driving siulator was processed on a virtual test tracks. This test-bed will be used to conduct testing on various ITS and ADAS technologies, such as adaptive cruise control (ACC), lane departure warning system (LDWS), cooperative intersection warning system as well as rollover stability control (RSC) and electronic stability control (ESC), etc. [ABSTRACT FROM AUTHOR]

The electronic air suspension (EAS) system can improve ride comfort, fuel economy and handling safety of vehicles by adjusting vehicle height. This paper describes the development of a novel controller using the hybrid system approach to adjust the vehicle height (height control) and to regulate the roll and pitch angles of the vehicle body during the height adjustment process (posture control). The vehicle height adjustment system of EAS poses challenging hybrid control problems, since it features different discrete modes of operation, where each mode has an associated linear continuous-time dynamic. In this paper, we propose a novel approach to the modelling and controller design problem for the vehicle height adjustment system of EAS. The system model is described firstly in the hybrid system description language (HYSDEL) to obtain a mixed logical dynamical (MLD) hybrid model. For the resulting model, a hybrid model predictive controller is tuned to improve the vehicle height and posture tracking accuracy and to achieve the on–off statuses direct control of solenoid valves. The effectiveness and performance of the proposed approach are demonstrated by simulations and actual vehicle tests. [ABSTRACT FROM AUTHOR]

Emissions standards for two- and three-wheeled powered vehicles are getting more and more stringent, and measurement procedures require to perform driving cycles with engine cold start. Therefore, a fast activation of the exhaust catalytic converter is of primary importance. In this work a numerical and experimental study of the exhaust system layout of a 125cc scooter has been carried out with the main objective of reducing the catalytic converter light-off time, without affecting engine performance and component cost. First, a 1D engine model has been developed to evaluate the impact of the component modification on engine performance. Then, a CFD-3D analysis has been performed to assess and evaluate the velocity and temperature fields of the gases inside of the muffler. After the numerical study, several prototypes have been designed and built for experimental tests. The engine has been installed on the dynamometric bench and instrumented. The exhaust system prototypes have been tested focusing on the engine brake performance and on the exhaust temperatures during warm-up transients. The latter has been monitored in several points inside the muffler, in order to obtain information about the catalytic converter operating conditions. The best prototype configurations have been installed on the vehicle and further road tests. The vehicle experimental results in terms of exhaust gas temperatures at the catalyst inlet and outlet highlight the improvements with the best exhaust prototype compared to the original configuration. [ABSTRACT FROM AUTHOR]

The electronic control brake technology for unmanned driving is researched based on a 4 × 4 manned light tactical wheeled vehicle. An electropneumatic brake system is designed according to the structure and characteristics of the original vehicle air brake, which realizes an electronic control brake function in unmanned driving mode, and reserves the manual brake function in manual driving mode. The two modes can be switched freely. The control characteristics of solenoid valve, vehicle rolling resistance coefficient on different roads, and the relationship among vehicle deceleration, speed and control input of electronic control brake are identified through vehicle test. The test results show that the electropneumatic brake system can rapidly and accurately respond to the braking request, and the user can flexibly switch between manual braking and electronic-controlled braking. The electropneumatic brake system can be used for the commercial vehicles. [ABSTRACT FROM AUTHOR]

This article discusses the mechanism and evaluation methods of contribution brought by regenerative braking to electric vehicle’s energy efficiency improvement. The energy flow of an electric vehicle considering the braking energy regeneration was analyzed. Then, methodologies for measuring the contribution made by regenerative brake to vehicle energy efficiency improvement were introduced. Based on the energy flow analyzed, two different evaluation parameters were proposed. Vehicle tests were carried out on chassis dynamometer under typical driving cycles with three different control strategies. The experimental results the difference between the proposed two evaluation parameters, and demonstrated the feasibility and effectiveness of the evaluation methodologies proposed. [ABSTRACT FROM AUTHOR]

On the base of analysis on the working state of wheels during skid steering of wheeled vehicles with consideration of the lateral nonlinear slip and uneven load distribution of tire, a turning resistance coefficient model for skid-steer wheeled vehicle is established with reference to the steering theory of tracked vehicles. Through real-time collection of the oil pressure data of steering mechanism, the turning resistance coefficients under different turning radius are indirectly measured. The results show that the accuracy of turning resistance coefficient model is acceptable , and the turning resistance coefficient of skid steer wheeled vehicles is smaller than that of tracked vehicles. [ABSTRACT FROM AUTHOR]

In view of the problems of large speed fluctuations and the tuning difficulty of regulator parameters when conventional PID control is used in robot driver, a new speed control method for vehicle robot driver based on adaptive fuzzy PID control is proposed in this paper. Specifically, the model for the coordinated control of multiple manipulators in vehicle robot driver is established first. Then based on this, an adaptive fuzzy PID speed controller for vehicle robot driver is designed to realize the speed tracking of given driving cycle. The results of test indicate that compared with conventional PID control, the proposed method can greatly improve the accuracy of speed tracking with a tracking error within the range of ± 2km/h, meeting the requirements of national vehicle test standards and ensuring the accuracy and validity of vehicle test data. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the design, tuning, and evaluation of a full-range adaptive cruise control (ACC) system with collision avoidance (CA). The control scheme is designed to improve drivers’ comfort during normal, safe-driving situations and to completely avoid rear-end collision in vehicle-following situations. Driving situations are divided into safe, warning, and dangerous modes. Three different control strategies have been proposed, depending on the driving situation. The driving situations are determined using a non-dimensional warning index and the time-to-collision (TTC). The control parameters of the proposed ACC/CA system are tuned by a confusion-matrix method using manual-driving data in no-crashing driving situations. The vehicle-following characteristics of the subject vehicle were compared to real-world, manual-driving data. Finally, the ACC/CA system was also implemented in a real vehicle and tested in both safe-traffic and severe-braking situations. It is shown that the proposed control strategy can provide natural following performance that is similar to human manual-driving in both high-speed driving and low-speed stop-and-go situations. Furthermore, it can prevent the vehicle-to-vehicle distance from dropping to an unsafe level in a variety of driving conditions. [Copyright &y& Elsevier]

For fuel cell hybrid vehicles, the energy distribution mechanism of the fuel cell and power battery should reasonably allocate the power output of the fuel cell and power battery, optimize the efficiency of both and control the power battery SOC to fluctuate within a reasonable range. To test the energy flow and operation characteristics of the powertrain of two hybrid car models on the market, two test vehicles (called vehicle A and vehicle B in this paper) are tested on an AIP 4WD chassis dynamometer under constant power and the China Light-Duty Vehicle Test Cycle-Passenger cycle condition, respectively. The test results show that vehicle A has a smaller power battery SOC variation interval and a lower variable rate than vehicle B. The cumulative power battery output energy of vehicle B is more significant than that of vehicle A. More importantly, the current rare public test reports of fuel cell vehicles make this study very valuable. This paper has important reference significance for the energy flow characteristics and energy management strategy of existing fuel cell hybrid vehicles. [ABSTRACT FROM AUTHOR]

Mist frequently forms on automobile windscreen glass in cold humid weather. The present paper describes the development of a control device for automatically demisting windscreen glass. Automatic demisting control is initiated when the surface temperature of the glass is lower than the dew point temperature at a given relative humidity and temperature of the cabin inside. It was decided to attach the sensors measuring surface temperature and humidity on the bottom right of the glass and on the back of the rear-view mirror respectively, based on the observation of experiments. The demisting control strategy was originally designed to increase blower speed, change mode, mix hot and cold air, and turn on/off the air conditioner as the mist formed increases. The automatic device was operated with the automatic temperature controller of a heating, ventilation, and air conditioning (HVAC) system and successfully demonstrated in a vehicle test in a cold chamber by following the designed control strategy. [ABSTRACT FROM AUTHOR]

• Energy flow tests for PHEV and ICEV were conducted under NEDC. • ICEV with turbocharged engine overcharges in non-supercharging conditions. • PHEV achieves decoupling of engine speed and torque while tank-to-wheel efficiency increases little. • Brake energy regeneration contributes most to energy saving. • The energy-saving rates of idling, braking and driving conditions are quantified. Energy flow analysis is an effective tool for refined development of vehicle to improve its energy efficiency. To reveal the energy-saving principles of hybrid vehicle, a plug-in hybrid electric vehicle (PHEV) which is in charge sustenance phase and a conventional vehicle with the same internal combustion engine (ICE) are selected to conduct energy flow test under New European Driving Cycle (NEDC) of cold start and warm start. Various energy distributions are quantified, the differences are compared, and the influencing factors are analyzed. Research results show that the conventional vehicle with turbocharged engine overcharges in non-supercharging conditions, and this phenomenon could be alleviated in hybrid vehicle. Tested PHEV could reduce the working range of engine to a certain extent through the electrification of powertrain, but the tank-to-wheel efficiency increases little. This indicates that the design purpose of powertrain topology is to ensure that the benefits of improved engine thermal efficiency outweigh the losses caused by longer energy transmission paths. Brake energy regeneration could reduce the demand for effective engine output, which contributes the most to energy saving, so the braking energy should be recovered as much as possible on the premise of safety and driving comfort. The proportion of exhaust gas enthalpy-increase for the tested PHEV is relatively high, and the use of exhaust waste heat recovery technology can further improve its energy efficiency. Compared with tested conventional vehicle, the energy-saving contribution rates of tested PHEV under NEDC are 5% for idling condition, 20% for braking condition, and −5% for driving condition, respectively. These provide guidance for further tapping the potential of hybrid vehicles. [ABSTRACT FROM AUTHOR]

Economic progress, development of transport, production of new cars, production of more and more energy, and the combustion of fossil fuels are causing huge changes that are currently occurring in the environment. Ecological problems of the contemporary economy combined with perspectives of resources exhaustion, as well as the need to follow sustainable rules of living, require the search for new fuels. Fuels which can assure their availability and good environmental performance are needed for maintaining sustainable transportation. Knowledge about the behavior of various fuels is necessary for realistic methods of technology management in transportation means and the fuel industry. This paper describes biofuels that can be an addition to petrol or can exist as standalone fuels. A simulation was carried out on an urban vehicle and the tested fuels were petrol 95, ethanol, methanol, and dimethyl ether. For the selected engine a simulation corresponding to that of the New European Driving Cycle (NEDC) test was created using the Scilab package. Based on this simulation, values of carbon dioxide and water vapor emission were determined. The fuel demand for each fuel mixture and the amount of air for the fuels used were also calculated (and verified on the basis of laboratory tests). It was demonstrated that addition of biofuel decreases emission of carbon dioxide, simultaneously increasing emission of water vapor. Biofuel additive also caused an increase in fuel consumption. Unfortunately, in the New European Driving Cycle test being investigated, carbon dioxide emissions in all cases exceeded the permissible level of 130 g CO2/km, which is bad news in the context of the further tightening of norms and standards. The simulation tests confirmed that when using the start/stop system and applying specific additives, the carbon dioxide emission decreases and the consumption of mixtures with the activated start/stop system is smaller. The analyzed problems and results of this analysis become more important in light of the Worldwide Harmonized Light Duty Vehicles Test Procedure (WLTP) standard, which became binding from September 2018 and applies to the sale of cars that had been approved prior (in accordance with the New European Driving Cycle standard). Although the NEDC standard appears obsolete the computer model simulating this type of test will be necessary in many cases. It is, however, needed and possible to develop a similar simulation procedure for WLTP tests. [ABSTRACT FROM AUTHOR]