Design And Implementation Of Fault Diagnosis System For The Whole Vehicle Controller Of Pure Electric Vehicle

In the electric,network,intelligent,sharing and environmental protection requirements are becoming more and more stringent,it has become an inevitable trend for traditional fuel vehicles to be replaced by more efficient and energy-saving pure electric vehicles.But because our country in recent years the rapid development of pure electric vehicles,lead to the lack of after-sales maintenance and technical personnel,the existing of the few technical personnel's skills shortage,now not only makes the high pure electric vehicle maintenance costs(time consuming power in auto fault diagnosis,inefficient)for troubleshooting,and also reduces the vehicle manufacturing enterprises after-sales customer satisfaction evaluation.Therefore,it is particularly important to add fault diagnosis system to pure electric vehicles.It is not only an important factor for the mass promotion of pure electric vehicles,but also an important way for vehicle manufacturing enterprises to quickly improve customer satisfaction,increase the market share of vehicle sales and improve vehicle safety.In this paper,the whole vehicle controller fault diagnosis system of pure electric vehicle is studied.The specific work and contents are as follows:1.In this thesis,based on the basic composition of the CAN network,introduced the SAEJ1939 protocol of application layer,network layer,data link layer and physical layer and network management,established a certain type of pure electric vehicle controller VCU communication protocol,and also the vehicle fault diagnosis and fault classification principle,diagnosis method carried on the thorough research and analysis,choose to take the data flow analysis method is used to on-line fault diagnosis.2.The control system of pure electric vehicle is analyzed from a global perspective,and the functions and principles of each component are introduced.The fault diagnosis scheme of pure electric vehicle is proposed.The function definition of VCU and the design of network topology structure of fault diagnosis system are completed.Then the VCU self-diagnosis strategy is proposed and the common fault diagnosis strategy design of each subsystem is completed.This thesis puts forward the active diagnosis strategy,and completes the design of the active diagnosis strategy that the vehicle can't get on the high pressure,can't run,and the equipment such as the air pump and steering pump doesn't work.3.According to the requirements of VCU fault diagnosis system,complete the software and hardware design of VCU diagnosis system,and formulate the CAN faultdiagnosis instruction;Completed the design of the whole vehicle power-on process,self-diagnosis process and power-on active diagnosis process,and took the battery management system fault as an example to complete the fault diagnosis program design with Codewarrior software.Completed the upper computer software design,including interface design,communication protocol formulation,serial communication implementation.Based on the intelligent interactive interface Z4000,the development of handheld diagnostic equipment was quickly completed,mainly including interface design,user programming and diagnosis function implementation.4.Built the vehicle fault test platform,read the real-time message of the test platform through can-View software,analyzed and compared the parsed message with the actual data of the upper computer,and verified the real-time monitoring and fault alarm functions of the upper computer.Then take the vehicle can not be on the high pressure as an example to remove the fault site,realize the upper computer active diagnosis function,diagnosis results stable ideal,can meet the early system functional design requirements.