Vehicle State Monitoring And Fault Diagnosis Based On OBD System

With the continuous development of vehicle technology,the car has developed into a complex mechanical and electrical hybrid system,so the traditional technology and methods have been difficult to accurately state monitoring and fault diagnosis of the vehicle.The development and popularization of OBD(on-board diagnostic)system provides a foundation for the establishment of a new type of vehicle state monitoring and fault diagnosis system.With the increasing amount of vehicle,more and more people begin to pay attention to the fuel economy and safety of the vehicle.For this purpose,this paper establishes a vehicle state monitoring and fault diagnosis system based on OBD-II system,this system can realize the real-time and on-line acquisition,analysis,transmission and display of vehicle status information and fault codes,statistical analysis of the long time vehicle status information,evaluate the economic performance of driving behavior,accurate description of the fault of the vehicle electronic system,and the statistical analysis of the long time vehicle fault information.Acquisition of real-time vehicle data and fault codes based on OBD system.According to the OBD-II protocol,the vehicle data acquisition system is established by using the form of the OBD vehicle data acquisition information collection,according to the OBD-II application layer protocol,the collected vehicle data frame is analyzed.On this basis,the data were matched for different vehicles,make the vehicle state data acquisition and keep the high efficiency,real-time,accuracy in different vehicle platform.Based on the vehicle data that has been acquired,the vehicle state on-line monitoring system according to the OBD-II diagnosis application layer protocol to resolve the vehicle data into a readable vehicle status information.Real-time on-line monitoring and display of vehicle status information for driver is realized,the threshold warning mechanism is set up.Fault code analysis of vehicle electronic system and display the describe of vehicle fault is realized.According to the principle of gasoline engine air fuel ratio,comprehensive utilization of a number of vehicle status information,a kind of calculation method of fuel consumption is established,which has high adaptation and high precision.Based on the long time vehicle data,the influence of different driving behavior on the fuel economy of vehicles is analyzed,the driving behavior characteristic parameters which affect the fuel economy of vehicles are presented,according to this,the driver's driving behavior is evaluated economically.Vehicle fault database is established,this database can precise description of fault codes,classified storage of vehicle electronic system fault,and statistical analysis of the long time fault codes of the storage system for user vehicles and vehicle models.According to the real-time vehicle data and fault code acquisition method,the OBD data acquisition hardware is designed.Based on portable navigation equipment(PND,Portable Navigation Devices)and WIN CE system,local on-line vehicle status monitoring software is designed.Based on remote server,vehicle state monitoring and fault diagnosis system is designed.Through vehicle experiment,verification of acquisition,transmission and analysis of vehicle state information,verification and optimization of fuel consumption calculation method for gasoline vehicle,verify the effectiveness of the driving behavior fuel economy evaluation model.