Jun Li

Study on the Dynamic Characteristics of Pneumatic ABS Solenoid Valve for Commercial Vehicle

As the most key parts of pneumatic Antilock Braking System (ABS) for commercial vehicle, the dynamic characteristics of pneumatic ABS solenoid valve directly influence on the effectiveness of ABS. Modeling and simulation of pneumatic ABS solenoid valve is presented in this paper on the top of MATLAB/ SIMULINK, Hardware in the Loop (HIL) test bed of pneumatic ABS is developed, and the test of dynamic characteristics of pneumatic ABS solenoid valve is completed. Based on the results of simulation and test, the factors which influence the dynamic characteristics of solenoid valve is analyzed, and the design guideline of solenoid valve is brought forward.

Integrative control strategy of regenerative and hydraulic braking for hybrid electric car

Since electric braking involvement, the braking system of an EV, HEV and FCV becomes much more complex than conventional mechanical alone braking system. The target in this hybrid braking system is to recover the braking energy as much as possible and meanwhile maintain a good braking performance for vehicle safety. For this purpose, the control of this braking system is very crucial. In this paper, a integrative braking control strategy has been developed and simulation model has been established, by which the braking performance has been validated, that includes energy recovering, braking feel and braking safety etc..

Development of a test bench for integrative evaluation of the pneumatic ABS/TCS performance

A test bench for integrative evaluation of the pneumatic activated ABS/TCS performance of a vehicle has been developed. The test bench is built based on the platform of Matlab/xPC. It can be used to test the performance of ABS/TCS ECU and the characteristic of pneumatic solenoid valve. It can also be used in guiding the design of a ABS/TCS product for original equipment manufactures (OEMs), or find the most suitable product among various market available ABS/TCSs for specific vehicle application for a vehicle manufacturer. The scheme of hardware and software of the bench is described in detail. The tests of braking and starting performance of a vehicle with ABS/TCS driving on the road with low adhesive coefficient and the road which experiences sharp changes in adhesive coefficient and the operating characteristic of the solenoid valve are taken as major test contents. The test results show that the bench can completely emulate the real operating characteristic of a ABS/TCS system as its operating on real roads

Development of Air-ABS-HIL-Simulation Test Bench

A PC-based-air-ABS-HIL-simulation test bench with low cost and high efficiency is presented in this paper which can be used to developed air-ABS for commercial vehicle. It has been developed in Matlab/Simulink environment with the real-time rapid prototyping tool: xPC target. The architecture, hardware, and software of this test bench are described in details. Utilizing the test bench, the real-time HIL-simulation tests for air-ABS have been completed. The results illustrate the effectiveness and applicability of the developed test bench.

Research on the Braking System Control Strategy of Hybrid Electronic Bus

As one of the key technologies of Hybrid Electronic Bus, regenerative braking technology can recover energy without changing the traditional bus braking habit. This is of vital importance in the research of regenerative braking system. Because the braking force distribution relationship between the front and rear axle of the vehicle has a remarkable influence in the braking stability,especially adding the regenerative braking force, the influence is even larger. So the anti-lock braking control strategy for the hybrid electronic vehicle is updated in this paper according to the condition of regenerative braking. The anti-lock braking control and regenerative braking control were integrated in one ECU (Electronic Control Unit) of braking control system, collecting signals of wheel rotate speed, vehicle speed, SOC and brake pedal position by CAN bus. And the output control commands are sent to the execution unit of anti-lock braking system and regenerative braking system. The effectiveness of energy regeneration and the braking stability of this strategy are tested on the off-line simulation platform.

Study on CAN Communication of EBS and Braking Performance Test for Commercial Vehicle

EBS (electronic brake system) can effectively control and adjust braking force acting on every wheel, reduce braking response time and braking distance, and make vehicle achieve much more braking stability. It is featured with CAN (Controller Area Network) communication by which the sensor signals and control command signals can be transmitted and received. In the braking performance test of EBS, conventional test methods have some inconvenience in existence. For example, the fixing of pressure sensors and wheel speed sensors is restrained by the installation position, and the precision of measuring is prone to be affected by the environment conditions. But based on CAN communication technology, the special testing instrument can be connected with CAN bus, monitoring and recording signals on the bus. Thus signals representing braking performance can be acquired through CAN bus.

Study on the Control Algorithm of Series Power Train for Fuel Cell Transit Bus

Developed control algorithm of series power train for fuel cell transit bus is presented systematically, which keeps fuel cell packs operation points on the locus of highest efficiency. The off-line simulation model of series power train for fuel cell transit bus is developed which includes sub-models of control system and controlled objective (such as fuel cell pack, motor, battery pack and so on). The debug and validation of control algorithm is performed on developed modular test facility. The results show that developed control algorithm can effectively keep fuel cell packs operating on the locus of high efficiency points and much more fuel economy can be achieved than that of conventional ICE power train, meanwhile battery SOC can be maintained within reasonable level without charging outside during cycles.