Design and Development of a Supercharger for Single Cylinder Diesel Engine

摘要

A single cylinder diesel engine is a major power source for agricultural work in small households in South East Asia for many years. Due to most of the agricultural machinery running engine in low speed range, the low-speed torque of engine is the key performance. In this study, the preliminary study of theoretical performance gain or lost at different levels of boost pressure and air-fuel ratio were investigated. Then the artificially boosted ambient air supply system as the variable boost pressure supercharger was set up to evaluate the effect of boost pressure and air-fuel equivalent ratio to engine performance. The information obtained was used to select the commercial supercharger unit and matching piping and speed ratio according to the optimal boost pressure and injected fuel. The result obtains were that the low speed torque can be increased while brake specific fuel consumption and smoke density were reduced significantly. But due to the high fluctuating intake air flow (characteristics of single cylinder engine) and limited space for mounting accumulator, the increased indicating power is much lost through the pumping and flow losses of supercharger especially in high speed range. This reason made the actual performance gain less much than that obtained from theoretical analysis.