Engine intake system

An intake system in an internal combustion engine comprising a cylinder block defining therein a cylinder bore;

• a piston slidably received in said cylinder bore;
• a cylinder head fixedly mounted on said cylinder block and having a recess formed in its inner wall at a location opposing the top of said piston;
• a compact combustion chamber defined in said recess in said cylinder head with a large squish area of a limited clearance formed adjacent thereto between the inner wall surface of said cylinder head and the top surface of said piston at its top dead-center;
• at least one intake port and at least one exhaust port opening into said cylinder at the inner wall surface of said cylinder head opposing the top of said piston;
• at least one of said ports opening into said large squish area and the other ports opening into said combustion chamber;
• intake passage means in said cylinder head connected with said at least one intake port for feeding a charge of air-fuel mixture to said combustion chamber through said at least one intake port;
• exhaust passage means in said cylinder head connected with said at least one exhaust port for discharging burned gas from said combustion chamber to the outside;
• said intake passage means comprising a light-load intake passage for introducing the mixture into said combustion chamber or said squish area in the circumferential direction of said cylinder bore so as to produce a swirl under light-load operation of the engine, and a heavy-load intake passage having an opening and closing valve adapted to be closed during light-load operation of the engine for introducing the mixture into said combustion chamber or said squish area in the direction parallel to the central axis of said cylinder bore so as to suppress the generation of a swirl.

An intake system in an internal combustion engine comprising a cylinder block defining therein a cylinder bore;

• a piston slidably received in said cylinder bore;
• a cylinder head fixedly mounted on said cylinder block and having a recess formed in its inner wall at a location opposing the top of said piston;
• a compact combustion chamber defined in said recess in said cylinder head with a large squish area of a limited clearance formed adjacent thereto between the inner wall surface of said cylinder head and the top surface of said piston at its top dead-center;
• at least one intake port and at least one exhaust port opening into said cylinder at the inner wall surface of said cylinder head opposing the top of said piston;
• at least one of said ports opening into said large squish area and the other ports opening into said combustion chamber;
• intake passage means in said cylinder head connected with said at least one intake port for feeding a charge of air-fuel mixture to said combustion chamber through said at least one intake port;
• exhaust passage means in said cylinder head connected with said at least one exhaust port for discharging burned gas from said combustion chamber to the outside;
• said intake passage means comprising a light-load intake passage for introducing the mixture into said combustion chamber or said squish area in the circumferential direction of said cylinder bore so as to produce a swirl under light-load operation of the engine, and a heavy-load intake passage having an opening and closing valve adapted to be closed during light-load operation of the engine and opened during heavy-load operation of the engine for introducing the mixture into said combustion chamber or said squish area in the direction parallel to the central axis of said cylinder bore so as to suppress the generation of a swirl;
• said intake port communicated with said light-load intake passage opening into said squish area.

An intake system in an internal combustion engine comprising a cylinder block defining therein a cylinder bore;

• a piston slidably received in said cylinder bore;
• a cylinder head fixedly mounted on said cylinder block and having a recess formed in its inner wall at a location opposing the top of said piston;
• a compact combustion chamber defined in said recess in said cylinder head with a large squish area of a limited clearance formed adjacent thereto between the inner wall surface of said cylinder head and the top surface of said piston at its top dead-center;
• two intake ports provided with intake valves respectively and at least one exhaust port opening into said cylinder at the inner wall surface of said cylinder head opposing the top of said piston;
• one of said intake ports opening into said large squish area and the other of said two intake ports opening into said combustion chamber;
• intake passage means in said cylinder head connected with said intake ports for feeding a charge of air-fuel mixture to said combustion chamber through said intake ports;
• exhaust passage means in said cylinder head connected with said said at least one exhaust port for discharging burned gas from said combustion chamber to the outside;
• said intake passage means comprising a light-load intake passage connected with one of said intake ports for introducing the mixture into said squish area in the circumferential direction of said cylinder bore so as to produce a swirl under light-load operation of the engine, and a heavy-load intake passage connected with the other intake port, having an opening and closing valve therein, said valve being closed during light-load operation of the engine and opened during heavy-load operation of the engine for introducing the mixture into said combustion chamber in the direction parallel to the central axis of said cylinder bore so as to suppress the generation of a swirl.