Experimental Investigation of Combustion and Emission Characteristics for Internal Combustion Rankine Cycle Engine under Different Water Injection Laws

This paper discusses a novel oxyfuel combustion method named internal combustion rankine cycle (ICRC) used in reciprocating engines. Water is heated up through heat exchanger by exhaust gas and engine coolant, and then injected into the cylinder during the combustion to control the oxyfuel combustion temperature and reaction rate. Moreover, evaporation of the water mist increases the mass of working fluid so indicated thermal efficiency of the cycle is enhanced. This study investigates combustion and emission characteristics of ICRC engine under different water injection laws. The results show that indicated work and thermal efficiency increases significantly due to water injection process. The properly increase of injection duration and pressure improve IMEP (Indicated mean effective pressure) and thermal efficiency. Engine stability becomes better under lower water injection pressure and less injection duration. Less water injection duration and better injection atomization causes lower HC emissions, while NOx emissions stay under low level.