Abstract
The heavy duty diesel engines have adopted many technologies for clean emissions and low fuel consumption, such as direct fuel injection combined with high injection pressure and adequate in-cylinder air motion, turbo-intercooler system and highly strong steel piston. By these technologies the diesel engines have achieved the one of the lowest CO_2 emission as prime mover. However the heavy duty diesel engines are strongly expected lower NO_X and PM emission levels than today. In this study the high boost and lean diesel combustion has been attempted by a single cylinder engine in order to obtain a good engine performance and clean exhaust emission. The experiment has been done under the conditions of intake air quantity up to 5 times of naturally aspirated (NA) engine and 200 Mpa injection pressure. The adopted pressure booster is external supercharger, which can control intake air temperature. In this engine the maximum cylinder pressure will increase and new technologies have been adopted, such as the monotherm piston for the endurance of Pmax 30 Mpa and also every engine part is designed newly. As the boost pressure increase, the rate of heat release is resemble to the injection rate and becomes sharper and combustion improves and also the brake thermal efficiency becomes better. The high boost and lean diesel combustion results in low smoke, ISCO and ISTHC without the ISNO_X increase and gives good thermal efficiency.
