Simulation and experimental research on a mixed pulse converter turbocharging system

Abstract

A newly developed turbocharging system, called a mixed pulse converter (MIXPC), is proposed and the performance of the proposed system applied to diesel engines is evaluated. The aim of this proposed system is to reduce the scavenging interference between cylinders, and to lower the pumping loss in cylinders and the brake specific fuel consumption (BSFC). In addition, exhaust manifolds of simplified design can be constructed with small dimensions, low weight, and a single turbine entry. An engine performance simulation code, in which a second-order finite volume method + total variation diminishing method is used to simulate the one-dimensional unsteady gas dynamic phenomenon in intake and exhaust pipe systems, has been developed. By simulating a locomotive diesel engine using the module pulse converter (MPC) turbocharging system and the MIXPC, it is found that not only is the average scavenging coefficient of the MIXPC larger than that of the MPC, but also cylinders of the MIXPC have more homogeneous scavenging coefficients than those of the MPC, and the pumping loss and BSFC of the MIXPC are lower than those of the MPC. To validate the prediction results, experiments on a locomotive diesel engine equipped with a MIXPC have been successfully completed. Experimental results show that the MIXPC turbocharging system reduces the exhaust gas temperature before turbine by 80°C and BSFC at part load by 4.3 g/kW h, and the exhaust gas temperatures at each cylinder outlet at high load are more uniform. The diesel engine equipped with the MIXPC has the potential to increase its power to 115 per cent load.