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Homogeneous Charge Induced Ignition (HCII) combustion utilizes a port injection of high-volatile fuel to form a homogeneous charge and a direct injection of high ignitable fuel near the Top Dead Center (TDC) to trigger combustion. Compared to Conventional Diesel Combustion (CDC) with high injection pressures, HCII has the potential to achieve diesel-like thermal efficiency with significant reductions in NOx and PM emissions with relatively low-pressure injections, which would benefit the engine cost saving remarkably. In the first part of current investigation, experiments were conducted at medium load with single diesel injection strategy. HCII exhibited great potential of using low injection pressures to achieve low soot emissions. But the engine load for HCII was limited by high heat release rate. Thus, in the second and third part, experiments were performed at high and low load with double diesel injection strategy.

This paper mainly deals with the harmful emission control problem of the diesel engine. Many research works have been carried out on the catalytic conversion of diesel emissions. First, a few kinds of catalyst are prepared, selected by Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). Three types of catalytic converter are developed. Engine bench tests on these converters loaded with selected catalysts are made. Testing contents are: (1) conversion rate of harmful gases; (2) reduction effect of exhaust smoke; (3) resistant performance of converters and their influences on the engine, etc. Finally, through comparison, the effective catalytic converter is installed on a folklift truck for testing and durability examination. Testing results show that the catalytic converter has higher conversion rate on gaseous emissions, especially for CO and NOx. After two months running, the conversion rates basically keep the original level.

The potential of diesel/gasoline RCCI combustion coupled with late intake valve closing (LIVC) and double direct injection of diesel for meeting high fuel efficiency with ultra-low emissions was investigated in this study. The study was aiming at high load operation in a heavy-duty diesel engine. Based on the reactivity stratification of RCCI combustion, the employment of double injection of diesel fuel provided concentration stratification of the high-reactivity fuel, which is to further realize effective control of the combustion process. Meanwhile, late intake valve closing (LIVC) strategy is introduced to control the maximum in-cylinder pressure and nitrogen oxides (NOx) emissions.