Optimization And Design Research For The Turbocharging System Of Vehicle Diesel Engine

In order to satisfy the requirement of energy saving and emission reduction, in thelast few yeas, the design of the diesel engine becomes more and more elaborate. It isimportant for the turbo diesel engine exhaust system to use the exhaust energyeffectively and ensure the smooth air cylinder simultaneously. Therefore, how todesign a turbo system is one of the key technologies to improve diesel enginelow-speed operating mode performance to be solved.In this paper, as the basis of the national “863” Project (2008AA11A116) andNatural Science Foundation of Hunan Province Project (11JJ6036), the main structureparameters of the turbo system were optimized and some improvements also weremade of the original engine exhaust manifold. The main work and innovations of thethesis are as follows:(1) The thermodynamics mathematics and simulation model for turbo dieselengine is established by GT-Power software. The four cylinder turbo diesel engine withdouble pulse system and single import turbine system were simulated and calculated.The effect of the different systems on diesel engine power, fuel consumption rate andscavenging coefficient were analyzed.(2) The effect of the system parameters of the main exhaust diameter, length,exhaust manifold diameter, length and cross section area on turbo diesel engine power,fuel consumption rate and the average effective pumping losses were analyzed. Anoptimization model that comes with the GT-Power software is set up to minimum fueleconomy, and joint optimization for the main structural parameters of the exhaustsystem in100%load.(3) By the comparative analysis of the solutions of turbo system and flow loss inturbocharger system,a new turbo system is designed, the old and newthree-dimensional simulation model of turbo system based on Fluent areestablished,velocity field and pressure field of the two turbine system are analyzed.The results show that: the economy, acceleration characteristics and scavenging effectsof the diesel engine equipped with the new turbo system are greatly improved.