Zaimin Zhong

A Fuzzy Logic Based Regenerative Braking Regulation For a Fuel Cell Bus

For a fuel cell bus, it is significant to equip the regenerative break system to enhance the fuel economy. A two-input, one-output Mamdanis fuzzy inference system is introduced to the regenerative braking model. Taking the safety working conditions of the batteries, the driving dynamics and the occupant comfort into consideration, the method can not only recycle the bus braking energy adequately, but also be adjusted easily according to the practical requirement. Through vehicle tests, the method proves to be a valid solution.

Vehicle starting control of wet-clutch for Continuously Variable Transmission

Starting control takes an important role in the CVT system, wet clutch control is the key of it. The simplified dynamic model and the influential factors of the clutch during starting process have been introduced in this paper, based on which two control methods: linear pressure control method and fuzzy control method are introduced, and combined with the real vehicle test, two control methods were applied on the test vehicle, and by analyzing and comparing the starting performance after the test, the conclusion is that fuzzy control is more suitable to reflect drivers intention, and it can realize smooth starting in all kinds of working conditions.

A Systematic Approach of Improving a Fault Tolerant Fuel Cell Bus Powertrain Safety Level

This paper focuses on the safety issue of fuel cell bus powertrain system. It demonstrates a systematic way of evaluation and refinement of the safety degree to advance the confidence of a kind of fuel cell bus powertrain system, and meanwhile a specific approach of safety level evaluation is used. Via functionally summing up the potential faults which may appear and cause economic losses or occupant injury, the deficiency of the powertrain is located. Based on the occurrence, the severity and the detecting possibility, the numerical expressions of the faults property are measured. Through combining these evaluating results, a general safety level can be achieved, which directly reflects the inappropriateness that should be adjusted or redesigned. Continuous improvement, including using the passive methods of hardware redundancy and the active methods of fault diagnosis, detection and fault tolerant control in the electric control system is carried out, leading to a much more reliable system and the updated safety level shows the enhanced confidence of the fuel cell powertrain system. In order to get a more practical control system, a hardware in the loop test bench is set up to test the performance of the controllers, the core of the powertrain system, under different working conditions, especially those when faults appear. The actual execution of the approach shows that it is an objective analysis method for the innovative powertrain system and can help to improve the system reliability of the fuel cell bus systematically.

A study on self-learning control strategy for AMT clutch key control parameter

Clutch kiss-point has static deviation caused by manufacture error and dynamic deviation caused by friction plate wear. Without corresponding sensor, input shaft speed is calculated by vehicle speed. Maximum crankshaft acceleration and hysteretic nature of input shaft speed are analyzed. To overcome static deviation, an offline self-learning strategy is proposed, in which clutch engages under fixed-step to overcome the above-mentioned hysteretic nature. To overcome dynamic deviation, an online adaptation algorithm is proposed, in which kiss-point is identified by input shaft speed delay time and maximum crankshaft acceleration. Verification tests on vehicle show that the strategies achieve expected effects.

The research of powertrain for supercapacitor-based series hybrid Bus

Based on the characters of city bus, series hybrid powertrain featuring dasiaAuxiliary Power Unit (APU) + Super capacitor (SC)psila is recommended. With the proposed powertrain configuration, this paper develops a dual-power system for hybrid city bus. The constitution, working principle and relevant control strategies of the system are introduced in details. A novel dual-power structural system was synthesized with gear-box as integrative mechanical design to improve dynamic performance relating to maximum speed, acceleration, climbing etc. Examples of experimental data based on the dynamometer platform under the given urban cycle condition and actual road testing are illustrated. The results show the on-off control strategy is feasible and the adopted powertrain of this hybrid city bus can meet the design target and requirement.

Modelica based modeling of automotive transmission

We propose an approach for modeling automotive transmission system using Modelica language. This approach includes dynamic models of clutch and synchronizer, and definition of a system structure for vehicle modeling. This approach enables building of detailed models of a complicated system more easily, and reusing models for different projects. A hybrid transmission is constructed using the approach proposed, and is integrated into the structurized vehicle model. This hybrid vehicle is validated in a virtual NEDC experiment.

Automotive powertrain co-simulation with Modelica and Simulink

We highlight an automotive powertrain co-simulation solution for developing SiL (Software in loop) simulation environment. This solution provides a co-simulation interface for importing control algorithm from Simulink to Modelica environment using RTW toolbox. Detailed illustration is given on how to realize this co-simulation interface. To verify the co-simulation solution, a SiL environment is constructed for an AMT control software, and a virtual vehicle acceleration experiment is launched in a Modelica simulation environment. This experiment gives reasonable results and validates the co-simulation solution.

Shifting Control of a Novel Active Transmission for Hybrid Vehicle without the Use of Clutch

ICE speed adjustment problem, which is encountered during gear shift process without disengaging clutch under traditional AMT, was introduced. Working principle and structure of a novel fixed axis gear active transmission were described, by which EM couples with the input (HEV-SI) and output shaft (HEV-SO) selectively by automatic switch actuator. Under the former mode, EM can work efficiently by using the gear ratios properly and help ICE to decrease its speed effectively during gear shift process without disengaging clutch. Simulation results validate feasibility of the control algorithm.

Transient control of motor speed in Vehicular Active Transmission

A transmission integrated with more than one motor is defined as Vehicular Active Transmission. It can not only transmit the mechanical power, but also convert the energy between electrical and mechanical. The transient control in gear or mode switching process is one of the key technologies of active transmission. This paper applies optimal control theory to motor speed control in the process of gear shifting. The simulation comes to good control results that the motor reach rapidly target speed and keep stable around, which validates the feasibility of this motor speed control method.

The analysis of the factors impacting energy feedback efficiency of fuel cell vehicles

In this paper our research mainly focuses on the energy feedback efficiency of the new energy vehicle through the index for complete vehicle and the relevant parameters of vehicle powertrain. All the word is based on the detailed analysis of the data of vehicles practical operation and the research object is the fuel cell vehicle from Tongji University and Shanghai Fuel Cell Vehicle Powertrain Co., Ltd. (SFCV). Through the analysis and calculation, we obtain the values of the feedback efficiency under different running conditions and the key factors impacting the energy feedback efficiency of fuel cell vehicle. By adjusting these key factors, we analyze the variation tendency of the feedback efficiency and come to some conclusion.