Design Of Remote Monitoring System For Vehicle Tail Gas Emission Based On OBD Detection Data

In recent years, with the rapid development of urban motor vehicles in China, the road congestion, road safety and vehicle emissions become more and more serious and much unnecessary trouble is brought to the management department, which are caused by the driver behavior and vehicle system abnormal malfunction. With the raised and development of vehicle networking systems, that have become the mainstream trend to realize the remote monitoring of vehicle detection data and emission system, build the remote network of vehicle information data interaction, and improve the urgent demand of the intelligent traffic management. In this paper, with the background of the development for urban traffic and vehicle OBD technology, a remote monitoring system for vehicle emission inspection data is designed which provides technical support and implementation basis for the management remote control of urban traffic vehicle emission system and the development of the vehicle networking technology.Firstly, on the basis of the research of domestic and foreign OBD system and remote diagnosis technology, the structure of the vehicle remote emission monitoring system is presented based on OBD detection data. In view of the system components, the hardware and software components of the system are analyzed, and the function structure design of the system are proposed.Secondly, according to the system structure and the demand analysis, the communication of ECU data and the monitoring principle of emission system are studied respectively. First the vehicle communication protocol K line and CAN line are studies. The physical layer, link layer and application layer data of message frame are analyzed respectively. Then the algorithm of information frame for data flow and fault are analyzed, and the valid data and fault content are obtained. On this basis, the related systems of automobile exhaust catalytic converter, oxygen sensor, fire system principle are analyzed. After that the data flow and fault information systems for monitoring emissions are proposed.Thirdly, aiming at the system architecture, the detailed circuit and software implementation process of each module of the hardware diagnosis system are designed. The acquisition module circuit of OBD conversion chip EST327 on the K line circuit, the CAN bus protocol, GPS information collection, GPRS data transmission module circuit, serial communication module circuit and power supply voltage regulator circuit are designed respectively. Also the functions and principles of GPS and GSM for SIM808 are studied. The message analysis of GPS GPGLL information frame format,the GSM short message data transceiver and the GPRS wireless remote data transceiver are realized. Then by setting the controller LPC1765, it can be used to read the data of OBD protocol conversion chip and GPS information, and send the data to the server by the serial port.Finally, according to the system architecture, the software design and experiment simulation are carried out for the driving data remote monitoring system. First the software UI, sub function module and databases of data monitoring system are designed and implemented. Then by using the driving data remote monitoring system and MATLAB, the testing experiment of ECU simulation and vehicle is carried out and analyzed. By testing experiment, it is considered that the system basically realizes the function of remote monitoring of emission data.