Characteristics of Fuel Economy and Exhaust Emission in Turbo Intercooler ECU Common-rail Diesel Engines with a Combined Plasma EGR System

摘要

The characteristics of NO{sub}x and soot emissions under four kinds of engine loads are experimentally investigated using a four-cycle, four-cylinder, direct injection type, water-cooled, turbo intercooler ECU common-rail diesel engine with a combined plasma EGR system operating at three kinds of engine speeds. The purpose of this study is to develop a combined EGR and turbo intercooler system with a non-thermal plasma reactor for reducing NO{sub}x and soot emissions simultaneously, and improving fuel economy in ECU common-rail diesel engines. The EGR and turbo intercooler system is used to reduce NO{sub}x emissions, and the non-thermal plasma reactor and turbo intercooler system is used to reduce soot emissions. In this study, the plasma system is a flat-to-flat type reactor applied by plasma power supply. Exhaust gases emitted from the engine are directed into the inlet port of the plasma system, and react with radicals formed by the plasma reaction, thereby reducing NO{sub}x and soot emissions. The experiments are performed at the variable fuel injection timing between BTDC 15° and ATDC 1° according to the combustion state. It is found that the specific fuel consumption rate with EGR increases but the fuel economy is better than that of mechanical injection type diesel engine compared with output. Results also show that NO{sub}x and soot emissions decrease as the applied electrical voltage of the non-thermal plasma reactor is elevated. On the other hand, soot emissions increase but NO{sub}x emissions decrease as the EGR rate is elevated. Thus we can conclude that the influence of EGR in NO{sub}x emissions is greater than that of the non-thermal plasma reactor, while soot emissions are influenced much more by the non-thermal plasma reactor than EGR.