Effects of I-EGR and Pre-Injection on Performance of Gasoline Compression Ignition (GCI) at Low-Load Condition

Gasoline compression ignition (GCI) has been considered as a promising combustion concept to yield ultra-low NOX and soot emissions while maintaining high thermal efficiency. However, how improve the low-load performance becomes an urgent issue be solved. In this paper, GCI engine model was built investigate effects of internal EGR (i-EGR) pre-injection on in-cylinder temperature, spatial concentration mixture OH radical, emission characteristics, control strategy for improving further explored. The results showed obvious expansion zone with equivalence ratio between 0.8~1.2 is realized by higher ratios, s decreases increase ratio, but increases i-EGR ratio. overlap among equivalent zone, high-temperature radical-rich can achieved coupled By increasing efficiency first then decreases, also achieves peak value 60% unaffected i-EGR. CO, HC, NOX, reduced low levels combination ratios 60%.