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Proton Exchange Membrane Fuel Cell (PEMFC) power system is an environmental-friendly energy conversion device and its operating life is determined by the single cell of worst output performance. Therefore, high stack voltage uniformity benefits to prolong its durability under the dynamic loading process. This work experimentally researches a stack voltage uniformity under the dynamic loading process from open-circuit state (28.6 V) to nominal voltage (18 V). Different dynamic loading strategies, namely constant loading rate strategy, decreasing loading rate strategy, and square increasing loading rate strategy, are elucidated and compared. The results reveal that constant loading rate strategy displays a slight fluctuation of Cv values compared to other strategies and effectively maintain the stack voltage uniformity for its instantaneous response process.

Considering the impact of battery life on the life cycle cost of plug-in hybrid delivery vehicles, a multi-objective optimization study on battery charge and discharge power is carried out with the goal of minimizing comprehensive fuel consumption and battery life attenuation. The weight coefficient is introduced to transform the multi-objective optimization problem into a single-objective optimization problem. And use the dynamic programming (DP) algorithm to solve the problem of global optimization, and the optimal weight coefficient is selected according to the optimization result. The simulation results show that, this method has effectively reduced the battery life attenuation degree while ensuring fuel economy, and the life cycle cost of hybrid electric vehicles was optimized. Besides, it can provide research support and evaluation benchmarks for other types of energy management optimization strategies.

The existing intelligent cruising assist system lacks comprehensive and objective test and evaluation scenarios. First, this paper analyzes the existing standard related to intelligent cruising assist system. Then, based on the current natural driving data, the paper analyzes the driving behavior of drivers, and extracts the information of speed, distance and road conditions in the Cruising scenario. Finally, this paper designed the test and evaluation scenarios of intelligent cruising assist system: the longitudinal control ability of one lane, the lateral control ability of one lane, the longitudinal and lateral control ability of one lane, Automatic lane change ability. The test and evaluation scenarios designed in this paper are used for the test and evaluation of intelligent cruising assist system at L2 level.

Multi-speed transmissions can improve power and economy performance of battery electric vehicles (BEVs), thus becoming an inevitable trend in automotive industry. A two-speed dedicated electric transmission (2DET), which can realize switching of two gear ratios through two wet clutches, is explained firstly. Secondly, 2DET is developed and a prototype is assembled in a BEV of Beijing Electric Vehicle Co. Ltd. (BJEV). Thirdly, the differences of new European driving cycle (NEDC) and China light duty vehicle test cycle passenger (CLTC-P) are compared. Fourthly, the parameters of battery cell are tested and a simulation model of the whole vehicle with 2DET is built. Finally, vehicle economy performance under NEDC and CLTC-P is simulated, and the results are validated in bench tests. Comparison shows that the economy simulation results match the test results, and the vehicle economy under CLTC-P is better than NEDC, with an increase of 1.16%.

Aiming at the problem of configuration selection of hybrid electric bus, a method of configuration optimization of plug-in hybrid electric bus is proposed. Several hybrid system configurations (P2, EVT+2AMT, EVT+CL1) for bus are presented, and the basic parameters of each system and the advantages and disadvantages of each configuration are introduced. The life cycle cost differentiation model of hybrid system configuration is established with the vehicle life cycle cost as the optimization index. On the premise of meeting the vehicle dynamics, the system configuration with the lowest life cycle cost is selected as the optimal configuration. To verify the rationality of the optimal hybrid system configuration, the fuel price and vehicle service life are selected as sensitivity factors to analyze the sensitivity of the life cycle cost differentiation model.

The determination of the thermal load of the passenger compartment is the premise and key of the air conditioning system design. There is a difference between the vehicle thermal load obtained from the conventional theoretical calculation and simulation analysis and the actual thermal load, and the difference is not easy to quantify. The experimental research is based on the steady-state research under the state of heat balance, which cannot meet the development demand for the prediction of vehicle cooling performance. In this paper, the method of one-dimensional simulation and three-dimensional CFD analysis is used to analyze the transient change of the temperature in the passenger compartment, and the thermal load model of an SUV is calibrated through a real vehicle test.

In this paper, a torque vectoring controller is proposed for the distributed-drive electric vehicles to simultaneously prevent loss of traction from excessive wheel slip and enhance vehicle lateral stability. In order to know the expected generation of direct yaw moment for vehicle lateral stability, this study provides two computationally efficient laws for comparisons which are fuzzy logic method and sliding mode method. Besides, a control-oriented model is formulated to describe the plant in mathematics. To satisfy the requirement of direct yaw-moment output and the control input constraints, sequential quadratic programming is adopted to find the optimal distribution for the drive wheel torques aiming at achieving the maximum tire grip margin. Moreover, a proportional-integral controller is designed to compensate the drive wheel torque for the purpose of preventing the excessive wheel slip.

Online fault diagnosis efficiency and accuracy are important issues to improve the performance of the proton exchange membrane fuel cell. Electrochemical impedance spectroscopy is an effective tool to detect the state-of-health of fuel cell for laboratory research. However, its measurement time is too long in online use. This paper shows an online fault diagnosis method just based on a single impedance. First, electrochemical impedance spectroscopy was used to deal with monitoring of flooding and drying of a commercial fuel cell stack comprised of six cells and obtained impedance spectra in different state-of-health. Next, the specific frequency impedance is extracted from the impedance spectrum, considering the sampling time and the sensitivity to different water content. The optimal frequency is selected by the combination weighting method rather than subjective decision.

The planetary gear powertrain with wet clutch can avoid the shortcomings of simple planetary hybrid system such as parasitic power and insufficient pure electric power, but the increase of components will lead to complex system structure and increase the difficulty of effective control. In order to provide accurate and reliable calculation basis for system control, this paper starts from the perspective of system modeling, based on the establishment of the wet clutch detail mechanism model, with reference to the powertrain dynamics and kinematics relationship to integrate the wet clutch torque to the planetary gear mechanism. Finally, a planetary gear powertrain mechanism model with a wet clutch was established. It is verified that the model of the wet clutch model planetary gear mechanism can accurately reflect the running characteristics of the components and provide a more accurate verification environment for the subsequent vehicle control strategy design.

Vehicles can achieve yaw moment control through longitudinal force distribution. For distributed drive electric vehicles, longitudinal force can be controlled by differential drive. It can correct vehicle attitude without limiting the traction performance, thereby improving vehicle stability and steering response. This paper presents a differential drive control strategy for a rear-wheel distributed drive electric Formula SAE (FSAE) race car. The control strategy aims at improving vehicle stability and steering response. The control variables are the yaw rate and the sideslip angle, and the sideslip angle is estimated by Kalman filter. Cascade control is used in the control strategy. The outer loop is responsible for correcting the yaw rate and the sideslip angle and distributing the tire longitudinal force. The combined controller of yaw rate and sideslip angle is based on linear quadratic regulator (LQR).

Based on the principle of carbon footprint, this paper selects typical passenger cars, such as internal combustion engine vehicles (ICEV), plug-in hybrid electric vehicles (PHEV) and battery electric vehicles (BEV) in the market of China as the research objects, and compares the energy consumption and carbon emissions of the three vehicle models in the whole life cycle for three major stages of manufacturing, driving and recycling in three representative cities. The results show that the manufacturing energy consumption of BEV is 5 times of HEV and 10 times of ICEV. For the BEV, only after driving a certain mileage it can be a less the unit energy consumption and emissions than ICEV. The whole life cycle carbon emissions of passenger cars with different power types is not only related to mileage, but also related to the energy structure of local electric power supply.

Over the last decade, the electric vehicle (EV) has significantly changed the car industry globally, driven by Li-ion battery technology's fast development. However, the fire risk and hazard associated with this type of high-energy battery has become a significant safety concern for EVs. This report focuses on the thermal safety of lithium ion battery (LIB) with different lithium plating morphology. The orthogonal experimental design method is used to control the LIBs cycle and lithium plating condition. The L34 table was designed for cycling the LIBs, considering temperature, cut-off voltage, charging rate and pressure. The safety was evaluated by accelerating rate calorimetry (ARC). The self-heating onset temperature (Tsh) and thermal runaway onset temperature (Ttr) comparison between new cells and lithium plating cells show a significant deterioration.

The parallel plug-in hybrid electric vehicle (PHEV) has two power sources of engine and battery and its thermal management is essential due to the complex powertrain, caused by multiple heat sources, variable temperature, and multiple temperature intervals. In this work, An integrated thermal management system (TMS) is designed for the parallel PHEV which includes a high-temperature (HT) coolant circuit, medium temperature (MT) coolant circuit, low-temperature (LT) coolant circuit, refrigerant circuit, and battery coolant circuit. In this model, the logic threshold method is used to formulate the control strategy and the temperature of each key component is selected as a control parameter. The integrated TMS model is built by AMESIM software.

High fidelity model of permanent magnet synchronous motors (PMSM) is of great importance to the research on the control of PMSM, as well as the development and test of motor control software. This paper briefly summarizes the high fidelity modeling methods of PMSM and the related difficulties such as accurate iron loss modeling, elaborating the modeling method based on finite element analysis (FEA) data or experimental data with motor currents as state variables. In order to calculate the iron loss accurately in the motor plant model, a high fidelity modeling method is proposed, which can comprehensively considers electromagnetic saturation, cross-coupling, and accurate iron loss obtained from FEA or experiment. A PMSM is modeled in Simulink using the proposed method and validated by FEA results, which verifies the effectiveness of the proposed method.

In this paper the significance of model-in-the-loop (MIL) simulation for the software development of permanent magnet synchronous motors (PMSM) is described. A MIL is developed not only for simulation and testing, but also for motor software development. All main components of a PMSM test bench are modeled, including a high fidelity PMSM model considering saturation, cross-coupling, iron loss and thermal characteristics, an inverter model considering dead time delay and inverter loss, a power source that can set a given supply voltage series or simulate a real battery, and a dynamometer model with good speed control performance. Virtual bench test of PMSM and its control software can therefore be conducted on the MIL. Several software development-oriented features are developed, enables the motor software to be developed step-by-step by a team simultaneously and efficiently. Simulation results are given to demonstrate the accuracy and effectiveness of the MIL developed.

Among known electrochemical batteries, Lithium-ion batteries are best suited for portable electronics and electric vehicles because of their highest gravimetric and volumetric energy density. The anode materials used so far in commercial lithium-ion batteries are still graphite, but its specific capacity has been unable to meet the market demand. SnO2 is a promising alternative due to its high specific capacity with 782 mAh/g, but there are many bottlenecks when it is used as anode material solely, such as poor electrical conductivity, high volume change rate. In order to suppress these deficiencies, porous nano-sized SnO2/graphene/activated carbon (CAC/GN/SnO2) composites with high electrochemical performance are prepared via hydrothermal method followed by a facile calcination.

Anthropometric data are crucial to vehicle ergonomics and safety design. The Chinese population has smaller body size than that of the Western population, while the current crash dummies were developed based on statures of the Western population. To provide effective crash protection for Chinese occupants and pedestrians, Chinese anthropometric data are needed. In the present study, three available Chinese anthropometric databases were surveyed and compared, and it was found that none of them can give reliable and complete anthropometric data. Thus, a mapping method was developed based on correlation and regression analysis to rebuild a reasonable and completed Chinese anthropometric database. Furthermore, the differences between Chinese body size and that of the current dummies were discussed and an example was given to demonstrate the influences of body size on injuries.

SAE J2534-1 defines a standard vehicle network interface that can be used to reprogram emission-related control modules. However, there is a need to support vehicles prior to the 2004 model year, as well as non-emission related control modules. The SAE J2534-2 document meets these needs by detailing extensions to API version 04.04 of the SAE J2534-1 specification. It is not required for an interface to be fully compliant with API version 04.04 of the SAE J2534-1 specification to implement some of the features specified in this document. Together, these extensions provide the framework for a common interface to protect the software investment of the vehicle OEMs and scan tool manufacturers. Only the optional features will be described by this document and are based on the December 2004 publication of SAE J2534-1.

Testing plastics to very low temperatures

No scope available.