A Potentiality of Dedicated EGR System for Improving Thermal Efficiency in Natural Gas SI Engines

Abstract

Object of this study is to realize improving thermal efficiency and emission reduction with low temperature combustion. EGR is a solution to low temperature combustion, however it occurs burning velocity decrease. To prevent this phenomenon, Dedicated EGR was adjusted to SI engine run by natural gas. The entire exhaust gas of a single cylinder operated by the equivalence ratio varied from lean to rich was recirculated to the other cylinders. Due to H2 and CO included in EGR, slowed burning velocity problem was overcome with increasing degree of constant volume, thus thermal efficiency could be improved.