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Engine start while driving is one of the most typical and frequent work conditions for hybrid vehicles. Engine start has very significant impact on the driving comfort. Engine start, especially a dynamical engine start, have high control requirements regarding control time, torque output and riding comfort. In some hybrid transmissions such as P2, engine is cranked and synchronized through wet clutch slipping. Because clutch pressure control has time-varying delay and estimation precision of engine torque by ECU (Engine Control Unit) is poor, conventional PID controller is unable to meet the high requirements of control quality. A new control algorithm is proposed in this paper to cope with all these challenges. The new control algorithm is based on LADRC (Linear Active Disturbance Rejection Controller) and is improved through combination with Smith predictor and Adaline network. LADRC is adopted to reduce negative effects of poor precision of engine torque.

Most of the existing energy management strategies for Extended-Range Electric Vehicles (E-REVs) are heuristic, which restricts coordination between the battery and the Range Extender. This paper presents an instantaneous optimization energy management strategy based on the Minimum Loss Power Algorithm (MLPA) for a fuel cell E-REV. An instantaneous loss power function of power train system is constructed by considering the charge and discharge efficiency of the battery, together with the working efficiency of the fuel cell Range Extender. The battery working mode and operating points of the fuel cell Range Extender are decided by an instantaneous optimization module (an artificial neural network) that aims to minimize the loss power function at each time step.

In order to research the vibration and noise reduction in pure electric vehicle power-train, a comprehensive work is to simulate the power-train incentive of a high-speed pure electric vehicle, and indicates significant impact of gear mesh system on the power-train NVH performance. Therefore, it is necessary to further study the impact of meshing gear system on electric vehicle power-train vibration and noise performance and seek reasonable methods to reduce the vibration and noise. In this paper, a typical pure electric vehicle's powertrain was used to conduct vibration and noise dynamic simulation. Firstly, the power train model was established considering the gear meshing stiffness, transmission errors, bearing factors and shell flexible, then the vibration and sound radiation dynamic response of power-train was simulated. Based on the accuracy of prediction model, a gear tooth modification was carried out for vibration and noise optimization.

On account of environmental friendliness, high energy conversion efficiency and high power density, the proton exchange membrane fuel cell (PEMFC) has been used for automotive application for years. However, its durability in powertrain system is one of technical challenges, which restricts the large-scale commercialization of fuel cell electric vehicles (FCEV). In addition to the complex aging mechanism of PEMFC, the durability and energy relationship of key components in powertrain system, including battery and DC/DC converter, have a crucial impact on the vehicle performance, which have not been thoroughly analyzed. Nowadays, most researchers have explored the causes of components degradation from models or experiments and tried to carry out the life expectancy. Nevertheless, it is in need of system-level researches on durability against the actual automotive application.

Because of the direct connection between the compound power split hybrid transmission (CPSHT) and the engine in hybrid electric vehicle (HEV), engine ripple torque (ERT) can lead to obvious jerks when the mode transition from electric driving mode to hybrid driving mode occurs. In order to enhance the riding comfort, two additional wet clutches are mounted in this novel CPSHT and the relevant coordinated control strategy is developed. Firstly, after the description of the mechanical and hydraulic parts of the novel CPSHT, the dynamic plant model including driveline model, engine ripple torque and clutch torque is deduced. Secondly, the mode transition process in the original and current designs are compared and analyzed with the equivalent level diagram and the encountered problems are stated.

Faced on transient vibration of EV, considering the characteristics of the electric drive system, active and passive integrated transient vibration control method of power train mounting system was proposed. Models of power train system and mounting system were established, modal characteristics were grasped by simulation and experiment. A feed-forward controller was constructed from the facet of active control, mounting system transient vibration and power train torsion vibration were reduced. Based on this, further optimization of mounting system was conducted from a passive control perspective. Results show that the active and passive integrated control method can effectively reduce the dynamic reaction force of mounting points, improve the vibration conditions of power train and vehicle body as well.

In view of the problem of low-frequency (less than 10Hz, such as 0.5Hz, 1.15Hz, 8Hz in this paper) longitudinal vibration exists in a pure electric vehicle, modeling methods of drive-line torsion vibration system are conducted. Firstly, dynamometer test is performed, signals of motor speed and seat rail acceleration are obtained, the frequency characteristics of flutter is determined using the order analysis and time frequency analysis. Then four types of modeling and analysis are investigated facing the drive-line torsion vibration problem, including single model without electromagnetic stiffness, branch model without electromagnetic stiffness, single model considering electromagnetic stiffness and branch model considering electromagnetic stiffness. The results show that, modeling taking into account the electromagnetic stiffness and branches can reflect more low-frequency characteristics helps to reveal the low-frequency longitudinal flutter of the researched electric vehicle.

Because of the vehicle market competitive and of the raise of customers' demanding, NVH performance became an important job, especially for new energy vehicles. As the electric vehicle moving into the direction of high speed and large torque, electric vehicle vibration and noise problems highlighted gradually. In recent years, CAE has played an increasing role in the design, development and optimization of powertrain NVH at component and system levels. The subject of this paper was the numerical and experimental evaluation of the electromagnetic and vibro-acoustic behavior of an electric powertrain. For this purpose, a coupled and fully flexible dynamics model of the electric powertrain was developed. Then electromagnetic forces including both radial and tangential force and gear mesh excitations including time-varying meshing stiffness, meshing error and meshing impact were computed, which were used to perform forced response analysis on the full FE mesh of the powertrain housing.

A novel compound power-split hybrid transmission based on a modified Ravigneaux gear set is presented. The equivalent lever diagrams are used to investigate the electric operating modes for the hybrid powertrain, and then its dynamic and kinematic characteristics as well as efficiency characteristics are described in equations. A brake clutch mounted on the carrier shaft is proposed to enhance the electric driving efficiency for the hybrid transmission. Three types of electric operating mode are analyzed by the simplified combined lever diagrams and the system efficiency and torque characteristics for these electric operating modes are compared. A major influence on output torque of the hybrid transmission derived from the torque capability of motors and brake clutch is depicted.

Several types of power-split hybrid transmissions are outlined and the strengths and weaknesses of typical compound power-split prototype designs are summarized in this paper. Based on an modified Ravigneaux gear set, a novel compound power-split hybrid transmission with compact mechanical structure is presented, its dynamic and kinematic characteristics in equations and operating modes are described, and then equivalent lever diagrams are used to investigate the proposed compound power-split device. Control strategies in different operating modes are discussed with the simplified combined lever diagram, and a global optimization method is implemented to find the optimum operation point for the hybrid powertrain. To evaluate the fuel economy of a hybrid car equipped with this hybrid transmission, a forward powertrain simulation model is developed and real vehicle performance tests are conducted in the chassis dynamometer.

The proton exchange membrane fuel cell (PEMFC) vehicle is one kind of new energy vehicle with fuel cell as power source, which has environmental friendliness, high power density and quick refueling. However, the productlization testing in powertrain system, especially for subsystems and key parts, is one of the critical technical challenges, which restricts the industry development and large-scale commercialization of fuel cell electric vehicles (FCEVs). In this paper, comprehensive testing requirement and latest testing technologies were reviewed, the development status and directions of testing technologies in FCEV powertrain system were presented. Based on comprehensive analysis, X-in-the-Loop (XiL) testing technology was proposed, and it is quite helpful to improve Real-time testing performance and functions for FCEV powertrain system. Furthermore, real-time and reliability as the two key factors for the XiL application was deeply analyzed and discussed.

Intelligent and connected vehicle (ICV) and new energy vehicle (NEV) will be two important directions of the automotive technology in the future, and the coordinated development of these two directions reflects relevantly the higher requirements put forward by nowadays society and people. Through the use of intelligent and connected technology (ICT), NEVs can exchange various traffic information data with the outside world (e.g. other running vehicles, road infrastructure, internet, etc.) in real time, which is so-called Vehicle to Everything (V2X). Based on the further analysis of the mutual traffic information, the vehicles can identify the current driving conditions and predict the future driving conditions effectively, which can realize the real time optimization of the energy management strategies (EMSs) of vehicles’ powertrain system, so as to meet the driving requirements of vehicles under different driving conditions.

The linear internal combustion engine-linear generator integrated system (LICELGIS) is a generating unit with high power density, high efficiency and low emission for the range-extended electric vehicle. The LICELGIS starts with the linear generator, which shows the advantages of speed, efficiency and emission reduction, as well as the prerequisite to guarantee the steady operation of the system. This paper focuses on the reversing control method and the energy utilization efficiency in the starting process of the LICELGIS. Pursuant to the starting requirements of the linear internal combustion engine, the fewest driving cycle and the evaluation index are obtained. Meanwhile, the velocity tracking mode and the position tracking mode is proposed for the control of the starting force reversing. The motions of the starting process under two control method are comparatively analyzed, indicating that the former has a high efficiency, while the latter is more likely to achieve.

Owing to its advantages of high energy density, quick start-up, and no emissions, the proton exchange membrane fuel cell (PEMFC) is one of the most promising power sources in transportation and has been used for automotive application for years. However, shortcomings in fuel cell key performances, such as lifetime and efficiency, characterized by state of health (SOH), restrict the large-scale commercialization for fuel cell electric vehicles (FCEV), raising demands for real-time state monitoring. Nowadays, most researchers have explored the reasons for state change from models or experiments. Nevertheless, it is in need of system-level researches on definition methods of SOH against the actual automotive application. Lacking accurate quantitative indicators, existing studies on health states are often qualitative and hence fail to consider intermediate processes.

Because a compound power-split transmission is directly connected to the engine, dramatic fluctuations in engine output torque result in strong jerks and torque losses when the hybrid vehicle is in mode transition from electric drive mode to hybrid drive mode. In order to enhance ride comfort and reduce the output torque gap during mode transition process, a brake clutch assisted coordinated control strategy was developed. Firstly, the dynamic plant model of the power-split vehicle including driveline model, engine ripple torque and brake clutch torque was deduced. Secondly, the brake clutch assisted mode transition process was analyzed, and the output torque capability was compared between cases of both brake clutch assisted and unassisted mode transition process. Thirdly, a coordinated control strategy was designed to determine the desired motor torque, brake clutch torque, engine torque, and the moment of fuel injection.