Search Results

The new idea incorporates an impinging part in the central piston cavity. A relatively low injection pressure, lower than that of a conventional IDI Diesel engine, and a single hole fuel nozzle are used. The fuel spray is injected against the impinging part, spreads and forms a fuel-air mixture. Since a comparatively rich fuel-air mixture always stays around the impinging part and ignition is accomplished near the center of the mixture, steady, instantaneous and high-speed combustion is possible. As the fuel-air mixture is formed mostly in the cavity, there is little fuel in the squish area. Therefore, it is possible to prevent end-gas knocking, and in spite of the use of spark ignition, to employ a higher compression ratio than that of the conventional premixed SI engine. Experiments with a single cylinder prototype (4-stroke cycle) engine with gasoline fuel showed that the maximum BMEP was 1.0 MPa and the maximum brake thermal efficiency was 37.7 % (217 g/kW.h).

A new type of internal combustion engine has been developed. The new idea incorporates an impinging part in the central piston cavity. The fuel spray is injected against the impinging area, spreads and forms a fuel mixture. Since a comparatively rich fuel mixture always stays around the impinging part and ignition is acomplished at the center of the rich fuel mixture, steady, instantaneous and high-speed combustion is possible. As the fuel mixture is always formed in the cavity, there is little fuel in the squish area. Therefore, it is possible to prevent end-gas knocking, and in spite of the use of spark ignition, to operate the engine at higher compression ratio than a conventional premixed SI engine. Experiments with methanol fuel showed that BMEP was 1.1MPa and the maximum brake thermal efficiency was 42%. The combustion noise was lower than that of diesel engine. Brief tests with gasoline showed a maximum brake thermal effiency of 36%.