Development Of Exhaust Gas Purification System For Gasoline Vehicle Emission Inspection Institution Based On Short Transient Loaded Mode

The number of motor vehicles in China is increasing year by year,and the regular inspection rate of automobile environmental protection is also rising.At present,Short Transient Loaded Mode has become the mainstream method of emission detection of light gasoline vehicles.Since the exhaust gas of gasoline vehicles is directly discharged to the outside world through the gas flow analyzer after the detection,a large number of emission detection vehicles,especially unqualified vehicles,will produce a large amount of exhaust gas,which will seriously endanger the health of inspectors and the surrounding atmospheric environment.This paper aims to develop an exhaust purification device that can efficiently collect and purify the exhaust of gasoline vehicles in the process of emission detection,so as to purify the exhaust pollutants produced by gasoline vehicles in the process of emission detection and remove this fixed air pollution source from the source.Firstly,based on the functions to be realized by the tail gas purification system,the mechanical structure design scheme of the tail gas purification system is determined and processed and installed,including flow measurement system,electric heater,tail gas purification post-treatment system,connecting pipes and sensors.Based on the current external purification technology route of diesel vehicle aftertreatment device combination,the exhaust purification and aftertreatment technology routes suitable for gasoline vehicles are analyzed,which are NSR+DOC purification technology route and DOC+SCR+ASC purification technology route respectively,and the two schemes are compared through tests.Secondly,the measurement and control system of the tail gas purification system is designed based on the functions and work flow of each component of the tail gas purification system.In terms of hardware design,the minimum system circuit of single chip microcomputer is designed based on XE164 FN single chip microcomputer chip,the power supply system circuit that can provide 5V and 3.3V power supply voltage is designed,the CAN communication circuit and RS-232 communication circuit that can realize communication function are designed,and the on-off signal processing circuit,analog signal processing circuit,output pulse signal processing circuit and DA conversion module circuit that can realize signal processing function are designed,the fuel injector driving circuit,relay and solenoid valve driving circuit which can realize the driving function are designed,PCB design is completed based on software Altium designer release 10 and handed over to professional manufacturers for processing.In terms of software design,the host computer software is developed based on Delphi software.According to the functions to be realized by the host computer,the three host computer interface function modules of vehicle information registration,device hardware self inspection,information query and report printing are completed,and the general program design of tail gas purification system and the subroutine of electric heater heating adjustment in the general program are completed Injection subroutine design of urea injection system,general program design of NSR device regeneration,fuel injection subroutine of fuel supply system and air supply subroutine of compressed air supply system in the general program.Finally,the purification effect verification test-bed of the tail gas purification system is built to detect the conversion rate of various exhaust pollutants.Through the test,it is found that the tail gas purification system under the two technical routes has good purification effect.