Development Of The Selective Catalytic Reduction(SCR) Electronic Control System For Diesel Engine Meeting China ? Emission

Reducing the impact of toxic and harmful components in the exhaust emissions of vehicles on air quality has been increasingly popular with the world's attention and strict control.China has issued special regulations,which stipulate the third,fourth and fifth generation emission standards of automobile exhaust(referred to China ?,China ? and China ? emission regulation).It is difficult to make the exhaust emissions of vehicles to achieve China ? only by purifying the engine machine,as after-treatment technology is needed.The work of this paper comes from the engineering needs of Chongqing CVS Environmental Protection Technology Co.Ltd.The diesel engine exhaust emissions control method has been studied in the paper.On the basis of comprehensive analysis of domestic oil,road conditions and existing after-treatment technology at home and abroad,Selective catalytic reduction(SCR)technology has been used to realize the after-treatment of diesel engine exhaust gas,which makes the exhaust emission of diesel engine meet the requirements of China ? emission regulations.In this paper,an electronic control system has been designed and developed for SCR system.By collecting and processing various signals,the control of SCR system has been realized according to the control policy requirements and standard protocol specification.The electronic control system has been used to make the SCR system and diesel engine work together.A bench test system has been set up and theEuropean steady-state cycle(ESC),European transient cycle(ETC)and World harmonized transient cycle(WHTC)tests have been completed according to the requirements of the China ? regulations.Test results show that the SCR electronic control system meets the design requirements and is of practical value.The diesel engine with SCR system can meet the requirements of China V emission regulations.The paper mainly completed the following work.Firstly,according to the principle of SCR system,the paper analyzed the functional requirements of the system,and designed the technical scheme.Secondly,the paper completed the hardware design of SCR electronic control system,including microprocessor selection,power management circuit design,CAN bus interface design,driver circuit design,sensor signal acquisition circuit design,PCB design and three proofing processing,etc.Thirdly,the paper completed the software design of SCR electronic control system,including system self-test design,metering pump task management and scheduling design,DCU management design,DSM management design and so on.Fourthly,the paper built a bench test system,and tested the SCR system by matching diesel engine according to ESC,ETC and WHTC test cycles.In the end,the SCR control system designed in this paper has been successfully matched with the YCD series diesel engine of Yuchai power machinery co.,ltd to meet the requirements of China V emissionregulations.