Search Results

Meeting the future exhaust emission and fuel consumption standards for passenger cars will require refinements in how the combustion process is carried out in spark ignition engines. A direct injection system decrease fuel consumption under road load cruising conditions, and stratified charge of the fuel mixture is particularly effective for ultra lean combustion. On the other hands, there are requirements for higher output power of gasoline engines. A direct injection system for a spark ignition engine is seen as a promising technique to meet these requirements. To get higher output power at wide open throttle conditions, spray characteristics and in-cylinder air flow must be optimized. In this paper, the engine system, which has a side injection type engine and flat piston, was investigated. We tried some injectors, which have different spray characteristics, and examined effects of spray characteristics on combustion of the direct injection gasoline engine.

Meeting future exhaust emission and fuel consumption standards tor passenger cars will require refinements in how the combustion process is carried out in spark ignition engines. A direct injection system decrease fuel consumption under road load cruising conditions, and stratified charge of the fuel mixture is particularly effective for ultra lean combustion. To achieve stable combustion at an ultra lean air fuel ratio, fuel spray speed, angle, droplet diameter and in-cylinder air behavior must be optimized. In this paper, the engine system which has an injector and spark plug located in the center of combustion chamber, and has a flat type piston was investigated. We adopted a swirl type injector (fuel pressure 5MPa) which gave a droplet diameter of 20 μ m. Swirl air motion was applied in the cylinder to concentrate the fuel mixture at its cylinder center. Fuel spray speed was decreased to under 30m/s to keep the mixture at the top of the cylinder.