Simulation Of Diesel Engine Air System Based On LabVIEW

Air system is a major subsystem of diesel engine. Air system design has great influence on Air-fuel ratio, EGR rate and engine delta P, thereby affecting the diesel power, economy and emissions. The traditional diesel design, which is based on large scale experiment, has defects of long development cycle and high cost. With the promptly progress of computer technique and gradually maturity of mathematical modeling theory, numerical simulation is becoming a common technical mean in diesel engine design and development. Simulation of diesel air system could achieve system performance prediction and preliminary estimates of the range of design parameters, therefore, could auxiliary to the system design.The working process of the engine was analyzed. The physical and mathematical model of turbocharger, intercooler, EGR loop, intake and exhaust pipes, air filter and exhaust after-treatment device, which are key components of air system, were deeply studied. On the basis of system analysis and study, a one-dimensional simulation model of diesel engine air system was built though Lab VIEW. The calculation results of simulation model were qualitatively and quantitatively compared with AVL-Boost, GT-Power and bench test data. Thus the validity and accuracy of the model were verified. The influence of key design parameters to performance parameters of air system were analyzed according to the simulation model. Consequently, performance prediction and preliminary estimates of the range of design parameters were achieved.Results show that the calculation results of air system simulation model meet the5%error requirement of engineering practice. The validity of model has been proved. At the same time, the impact of flow area of the turbine, turbine efficiency, EGR valve opening degree on Air-fuel ratio, EGR rate, engine delta P have been analyzed quickly and easily though system simulation. Such aiding systems development, reducing the experimental times and shortening the development cycle have been identified as possible through air system simulation.