Study on Performance Optimization of Car Diesel Engine with VNT Based on One-Dimensional Simulation and Experimental Verification

To research the performance optimization of high speed car diesel engine，firstly according to the characteristic of car diesel engine with Variable Nozzle Turbocharger (VNT)， one-dimensional cycle model of the engine was established by using simulation software BOOST and validated by experimental data in this paper. The turbine blades’ opening corresponding to different speed was determined. Therefore the problem that the VNT surges at low engine speed and the inlet air flow is insufficient at high speed was solved. Based on the above model, this paper improved the efficiency of the engine by optimizing the compression ratio and the distribution phase of camshaft and then used the experimental data to check the simulation results. Meanwhile the fuel consumption and the possibility of the engine operation roughness decreased.