Abstract: A two-stroke cycle internal combustion engine has a sustained power stroke which results from delayed mixing of a stratified charge. Use of delayed mixing of an overall stoichiometric air-fuel mixture results in formation of a low amount of the oxides of nitrogen. Delayed mixing of a stratified charge is achieved by placement of a Helmholtz resonator cavity in the piston and peripherally just below the crown thereof. The Helmholtz resonator cavity communicates with the combustion chamber via a narrow slot made by undercutting the top edge of the piston. A port type intake valve is used. Pressurized air passing through the intake port during the exhaust phase of the cycle streams past the undercut top edge of the piston. After the engine cylinder has received a charge of fresh air the compression stroke is begun and the main chamber is filled with a slight fuel-rich gaseous charge. The companion Helmholtz resonator cavity receives only an air charge from the intake port.

Abstract: A four stroke cycle internal combustion engine is presented having a sustained power stroke which results from a delayed mixing of a stratified charge. Use of delayed mixing of an overall stoichiometric air-fuel mixture results in formation of a low amount of the oxides of nitrogen. Delayed mixing of the stratified charge is achieved by placement of at least one Helmholtz resonator cavity in the head or closed end of each combustion chamber. The Helmholtz resonator cavity communicates with the top end of the main combustion chamber via a narrow slot. On the intake stroke of each engine cylinder, the main chamber is filled with a slightly fuel rich gaseous charge while the companion Helmholtz resonator cavity is filled with air. During the compression stroke some of the rich air-fuel mixture is forced into the resonator cavity via the communicating slot. At or near TDC, the air-fuel mixture in the main chamber is ignited.

Abstract: A four stroke cycle internal combustion engine is presented having a sustained power stroke which results from a delayed mixing of a stratified charge. Use of delayed mixing of an overall stoichiometric air-fuel mixture results in formation of a low amount of the oxides of nitrogen. Delayed mixing of the stratified charge is achieved by placement of a Helmholtz resonator cavity in the head or closed end of each combustion chamber. The Helmholtz resonator cavity communicates with the main combustion chamber via a narrow slot made around the periphery of the top end of the chamber. On the intake stroke of each engine cylinder, the main chamber is filled with a slightly fuel rich gaseous charge while the companion Helmholtz resonator cavity is filled with air. During the compression stroke some of the rich air-fuel mixture is forced into the resonator cavity via the communicating slot. At or near TDC, the air-fuel mixture in the main chamber is ignited.