Abstract: A piston for use with a direct injection, spark ignition engine includes a piston body with a top face having a piston deck and a shallow bowl. Furthermore, the shallow bowl has a maximum depth that is in the range of one to five millimeters below the piston deck.

Abstract: A method is presented for improving performance of direct injection spark ignition internal combustion engines at high load conditions by increasing the degree of homogeneity of the air-fuel mixture during the intake stroke of the engine. The improved performance is achieved by adding a deflector designed to reduce intake air impinging upon the fuel spray and deflecting it to the intake side of the combustion chamber, thus facilitating better fuel circulation throughout the combustion chamber. This method improves engine performance at high load engine operating conditions.

Abstract: A stratified-charge combustion chamber system for a direct-injection spark-ignited (DISI) engine with a swirl-type airflow. An asymmetrical combustion bowl design in the top wall of the piston provides a wide area on the downstream side of the swirl flow and a harbor area upstream of the swirl flow in a direction further away from the fuel injector. The edge of the combustion bowl is comprised of smoothly-connected curves with large radii, except for the curve connecting the wide and harbor areas, which has a small radius. The vertical cross-sections of the bowl also have large radii in order to guide the air-fuel mixture and rebounded fuel droplets toward the spark plug and prevent dead regions for the fuel. The precise position of the spark plug in the harbor area can be adjusted as desired within a certain range to improve ignitability of the air-fuel mixture.

Abstract: A stratified-charge combustion system design for direct-injection spark-ignited engines with the piston bowl in the exhaust-valve side. The air flow from the inlet valve provides a normal tumble in cylinder air flow. The fuel injector is positioned on the intake-valve side of the combustion cylinder and forms a charge stratification in the combustion chamber. With the piston bowl on the exhaust-valve side, the distance for spray penetration of the fuel from the injector is extended. The rate of fuel spray penetration in the combustion chamber is reduced by counter air flow against the fuel spray. The air-fuel mixture is moved upwardly to the area of the spark plug by the tumble air flow for ignition. The invention provides less piston bowl wall wetting which results in less soot formation and less emissions of undesirable hydrocarbons.

Abstract: A stratified charge is formed in a direct injection engine by injecting fuel at a predetermined velocity, a predetermined droplet size, and forming the injected fuel with a hollow cone having a predetermined initial cone angle. The injected fuel thereby shallowly penetrates the combustion chamber so as to float therein to reduce wall-wetting and subsequent soot formation. A substantially flat top piston forms the injected fuel into a ball-shaped kernel during a compression stroke of the engine. The ball-shaped kernel remains substantially unmixed with the inducted air, thereby producing the stratified charge. The continued motion of the piston causes the ball-shaped kernel to move toward the spark plug for ignition.