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An improvement of thermal efficiency of internal combustion engines is strongly required. Meanwhile, from the viewpoint of refinery, CO2 emissions and gasoline price decrease when lower octane gasoline can be used for vehicles. If lower octane gasoline is used for current vehicles, fuel consumption rate would increase due to abnormal combustion. However, if a Homogeneous Charge Compression Ignition (HCCI) engine were to be used, the effect of octane number on engine performance would be relatively small and it has been revealed that the thermal efficiency is almost unchanged. In this study, the engine performance estimation of HCCI combustion using lower octane gasoline as a vision of the future engine was achieved. To quantitatively investigate the fuel consumption performance of a gasoline HCCI engine using lower octane fuel, the estimation of fuel consumption under different driving test cycles with different transmissions is carried out using 1D engine simulation code.

A wall-flow type diesel particulate filter system with reverse pulse air developed for vehicles should have the best regeneration performance possible with the least reverse pulse air as possible. We improved the reverse pulse air arrangement to decrease the air consumption and raise regeneration performance. Then, we developed diesel particulate filter (DPF) materials for the pore structure suitable for regeneration. Test equipment was designed to consume less air than a previous prototype system presented in our SAE paper [1]. The experiments used a soot generator simulating a diesel engine and a diesel engine. We confirmed that a wall-flow type DPF could possibly be applied to a regeneration system with the low air consumption for mounting on vehicles.