Study On Control Strategy Of Air-Assisted Urea Injection System Based On Offline Test

SCR technology is the main post-treatment technology to eliminate nitrogen oxides in diesel engines.SCR route is the mainstream technology of diesel engine after treatment adopted by China Ⅳ and Ⅴ countries.In order to solve the problems of long test period,high cost,many external disturbances and poor repeatability of SCR/SCR injection strategy calibration,testing and verification,this paper designed and developed an offline simulation test bench for SCR injection system,Meet the urea injection system on the input signal requirements,to get off the machine,the vehicle environment SCR injection system initial calibration,testing and verification capabilities.Relying on the built-in offline simulation test stand,the control strategy research and design improvement research on the market mainstream air-assisted urea injection system control strategy are carried out.The actual development proves that the SCR injection system off-line simulation test stand has good development effect,It obviously improves the development efficiency of SCR injection system control strategy,ensures the consistency of development verification,saves a lot of test costs on engine bench and vehicle,and has strong innovation and practical value.The control strategy of urea injection in the existing air-assisted urea injection system is analyzed and researched.According to the existing control strategies,such as packet timeout fault diagnosis strategy,air pipeline fault diagnosis strategy,power diagnosis strategy,purge strategy,Fault instrument support strategies were analyzed and studied and put forward the optimization program to enhance the service life of urea pump and vehicle matching adaptability.The control strategy of air-assisted urea injection system is verified by logic and accuracy using experimental means.In terms of strategy execution,the optimized strategy of this paper achieves the expected optimization goal.