|Title||C.S. Bae, "Effect of EGR on Combustion in a High Speed Direct-Injection Diesel Engine," pp173-194, Proc. UK-Korea Joint Seminar on IC Engines, Seoul, Nov. 1998.|
C. S. Bae, “Effect of EGR on Combustion in a High Speed Direct-Injection Diesel Engine,” pp173-194, Proc. UK-Korea Joint Seminar on IC Engines, Seoul, Nov. 1998.
High speed direct-injection diesel (HSDI) engine is a promising automobile power plant owing to its superior fuel economy. The effect of exhaust gas recirculation (EGR), one of the methods for reducing NOx emissions, was investigated in this study. The effect of various levels of EGR on the combustion characteristics has been investigated in a direct injection optical diesel engine in terms of the cylinder pressure, flame development, temperature and KL-factor distributions. Images of the developing flame under twelve engine operating conditions including 1000rpm/idle, 2000rpm/2 bar bmep and 2000rpm/10bar bmep at 0%, 30% and 50% EGR rates were obtained by means of two CCD cameras, in the absence of external illumination, with and without interference filters in the optical path. Analysis of these images has revealed that increased EGR rates lead to increased cyclic pressure variations during the warm-up period of the engine, reduced and more fragmented high-temperature regions, reduced flame core temperatures, generally reduced soot oxidation rates but similar ignition delay times. Overall, the effect of EGR on combustion increased with load and speed until a stage was reached at 50% EGR-rate and high load when combustion became unstable and the pressure trace highly non-repeatable.