Lu Qingchun

Performance comparison of different fuel cell vehicle power trains

The power train of fuel cell vehicle adopts the hybridization with a fuel cell system and an energy storage system, which can be battery pack or super capacitor pack, in order to improve the fuel economy of the vehicle through regenerative braking and possibly to increase the specific power and to decrease the cost of the power train. The hybrid power train of fuel cell vehicle can be different depending on the position, operation mode of the DC/DC converter and the type of energy storage system in the power train. The paper presents the four configurations of hybrid power train of fuel cell vehicle. The merits and disadvantages of every configuration of power train are analyzed, and the performance differences among them are presented. Experimental results of every configuration of power train, based on the same driving cycle, are given and discussed.

System identification of locomotive diesel engines with autoregressive neural network

As a complex nonlinear system, modeling analysis is an important method to the research of the static and dynamic characters of the locomotive diesel engines. Also the model facing the control behavior verification can be used in the electronic control units HIL(hardware-in-the-loop) simulation which can lessen the cost and uncertain factors in the later platform experiments. With the mode of system identification, this paper builds the dynamic model of the diesel with neural network. Aiming at the nonlinear character of the diesel with large inertia, the paper uses NARMAX(Nonlinear Auto-Regressive Moving Average with eXogenous inputs) as the main structure and uses LM(Levenberg-Marquardt) algorithm to train the network. In order to overcome the redundancy of the network structure caused by the artificial experience, this paper puts forward the Time Cycle Comparison method to determine the ranks of the input signals and uses the Optimal Brain Surgeon strategy to optimize the network structure. The simulation results proves that this method can eliminate the redundancy and improve the generalization capability of the network commendably under the same output error scopes. Comparison between the train results and the measured results shows that the dynamic model has the good real-time performances and little output error. So the model can meet the need of the system character analysis and technology application.

Thermal modeling of passive thermal management system with phase change material for LiFePO4 battery

The temperature of lithium-ion batteries in EVs must be maintained in a proper range for safety using and optimum performance. To solve the thermal problem of LiFePO4 battery, a passive thermal management system with phase change material (PCM) is discussed. D.C. resistance of the cell is measured by voltammetry method based on HPPC test, and the results can be used to calculate the heat generation rate. Paraffin is used as phase change material in this passive thermal management system. Thermal model of the system is established by finite element analysis (FEA) software, and the result is validated with experimental data. Compared to nature convection and forced air cooling, the maximum temperature of the cell decreases a little after using paraffin as phase change material.

Development and validation of emissions and fuel economy test procedures for heavy duty hybrid electric vehicle

Chassis dynamometer based test procedures were developed to benchmark the emissions and fuel economy performance of heavy duty hybrid electric vehicles (HEVs). And a hybrid electric bus (HEB) was tested according to the presented procedures to make a validation and get a picture of the HEB performance on the fuel economy, cold and hot start running emissions. Results show that the presented procedure is practical for heavy duty HEVs evaluation, and exhibited satisfying reproducibility.

Integration of fuel cell hybrid powertrain based on dynamic testbed

An experimental research platform based on dynamic testbed is developed and applied for fuel cell hybrid powertrain test and integration. Driver brake model is added to dynamic testbed to simulate brake process of electric vehicle. Test methods of sub systems and whole hybrid powertrain are investigated. Characteristic curve of sub parts and energy flow chart of hybrid powertrain are acquired through experiments on this testbed. Configuration of fuel cell hybrid powertrain is investigated. This platform provides a powerful tool for fuel cell powertrain research and development.

Software development of plug-in hybrid electric vehicle controller

Controller Software design for a plug in hybrid vehicle is presented to realize hybrid powertrian control strategy. Software structure is designed according to the functional requirements, the control strategy of energy management and coordinate control is developed on the basis of the structure, and the software is verified through off-line simulation and real-time simulation. Simulation results proved that the developed PHEV control strategy can meet functional requirements of hybrid powertrain.

A chassis dynamometer laboratory for fuel cell hybrid vehicles and the hydrogen consumption measurement system

To test and evaluate performance, fuel efficiency and emission of fuel cell hybrid vehicles, a laboratory equipped with a heavy duty chassis dynamometer is constructed by CATARC collaborates with Tsinghua University. The framework of the chassis dynamometer laboratory is designed. Then, three hydrogen consumption measurement methods are researched, and a hydrogen energy consumption measurement system for the laboratory is developed. Finally, the application of the chassis dynamometer laboratory is presented, especially several tests for the accuracy and the reliability of the hydrogen energy consumption measurement system is carried out. Certification tests and researches for both heavy duty and light duty fuel cell hybrid vehicles can be carried out in this chassis dynamometer laboratory.