Combustion and Performance Characteristics of a DI Diesel Engine Operating From Low to High Natural Gas Supplement Ratios at Various Operating Conditions

摘要

The compression ignition engine of the dual-fuel type has been employed in a wide range of applications utilizing various gaseous fuel resources, while minimizing soot and nitric oxide emissions without excessive increase in cost against that of the conventional direct injection diesel engine. Fumigated dual-fuel compression ignition engines are divided into two main groups: the conventional dual-fuel engines where part of the liquid fuel is replaced by gaseous one and the pilot-ignited ones where a pilot amount of the liquid fuel is used as an ignition source. Due to the high autoignition temperature of the natural gas, it can be used as a supplement for the liquid diesel fuel in conventional diesel engines operating under dual-fuel mode. Moreover, the use of natural gas as a supplement for the liquid diesel fuel could be a solution towards the efforts of an economical and clean burning operation. In the present work, experimental results are provided concerning the combustion of natural gas in a compression ignition environment, where the liquid diesel fuel is partially replaced by natural gas fumigated into the intake air. The experimental investigation has been conducted on a single-cylinder, naturally aspirated, high-speed direct injection (HSDI) diesel engine, located at the author's laboratory, properly modified to operate under dual-fuel mode conditions.