Abstract: An experimental investigation is conducted to study the premixed combustion characteristics and exhaust emission of a turbo-charged common-rail compression ignition engine fuelling with the gasoline/diesel blends. The effect of the gasoline ratio, EGR rate and fuel injection parameters on the combustion process and exhaust emission is explored. The results show that the gasoline/diesel blends can effectively prolong the combustion delay period and shorten the combustion duration, which is beneficial to increase the premixed combustion ratio. Increasing the proportion of gasoline can effectively expand the load range of premixed compression ignition and can reduce the exhaust smoke significantly without causing the increase of NO_x. The combination of gasoline / diesel blends and EGR technology is beneficial to reduce NO_x and exhaust smoke at the same time. With the introduction of EGR, the emission of NO_x shows a linear decreasing trend, and a good smoke emission can be achieved under the condition of low inlet oxygen concentration. At heavy load conditions, using EGR and two stage injection cooperative control strategy and reasonably calibrated pre-injection parameters can further improve the emission of the engine without reducing thermal efficiency

Key words: compression ignition engine, gasoline/diesel blended fuel, premixed-combustion, two-stage injection, EGR