Study On The Influence Of The Intercooler And Pressure Ratio Distribution On A Two-stage Turbocharging System

The contradiction between the environment and the increasingly serious problem of vehicle emissions in the world’s attention continues to heat up, which has become a hot issue around the world to discuss. As people always pursuit better performance of vehicle engines, exhaust turbocharging technology has essentially been further improved and developed for utilization. The exhaust turbocharging technology not only enhances the performance of engines, but more importantly reduces the engine emissions, meeting "energy saving and emission reduction",the world theme.Two-stage turbocharging system,compared with single-stage turbocharging system,makes more contribution to engine performance of power and economy. However,the influence of intercooler effects and distribution of system total pressure between the high-stage and low-stage on the two-stage turbocharging system is worth further researching and discussing.Through the test data, by theory analysis,this paper investigated the distribution rules between the two stages of total pressure ratio, one of the important parameters of the two-stage turbocharging system, and the expansion rules between the two-stages of expansion ratio, and the influence of pressure ratio distribution on the efficiency of the two-stage turbocharging system. An independent two-stage turbocharging system was built by GT-Power, a one-dimensional simulation software of engines, with high-stage turbine conditions and parameters of inlet and low-stage compressor parameters of inlet and different simulation conditions set, to investigate the influence of pressure drop and temperature of intercooler on the key parameters of the two-stage turbocharging system by calculation results.The results show that the pressure drop of intercooler directly influence the total pressure ratio of the two-stage turbocharging system. With the pressure drop of intercooler and the inlet pressure of high-stage compressor fixed, the total pressure ratio has something to do with the inlet temperature of high-stage compressor. Before stepping into the state of stalling, as the pressure drop of intercooler increases, high-stage compressor has the maximum efficiency. With the total pressure ratio fixed, higher outlet temperature of intercooler will lead to more pressure drop. With the outlet temperature of intercooler fixed, as the inlet pressure of high-stage compressor increases, the system total pressure ratio increases. However, the temperature of intercooler has no direct influence on the efficiency of low-stage compressor. The conclusions above serve as the theoretical base for the further development of two-stage turbocharging system with intercooler, while the calculation results remain to be verified on test bench.