LAUSR

The vital issue of response lag and soot emission during transient operation of turbocharged engine, has been studied so far mainly on experiment in engine system rather than turbocharger basis. The study of turbocharger transient performance, however, is extremely important to manufacturers due to the stringent regulations of exhaust emission and economy for the turbocharger engine. Therefore, a general method independent of the engine for evaluating the transient response performance of a gasoline turbocharger is proposed in this paper. First, an explicit relationship between key thermodynamic parameters of turbine and compressor and the evaluation index of D x that can characterize turbocharger transient response are established. Secondly, the proposed evaluation method is tested and verified using the coupling between GT-Power and MATLAB Simulink software based on the gasoline turbocharger. The simulation results show that the appropriate conditions should be selected for the transient response test, including the starting and ending speed, the starting mass flow rate, etc. For this proposed turbocharger, the value of D x has a good consistency when the ending speed is 200,000 r/min and the initial mass flow rate is in the range of 0.0715∼0.0756 kg/s. Moreover, the influence of rotor moment of inertia, turbine efficiency and compressor efficiency on D x is analyzed in this selected condition. Finally, the evaluating method of the transient response performance of the turbocharger is conducted on a test bench. The test results are in good agreement with the simulation results, indicating that the proposed evaluation method for transient response of turbocharger has a good predictability and can be used for quantitative evaluation of transient response-ability for different turbochargers independent of engine.