Abstract: A helically-shaped intake port comprising a helical portion formed around an intake valve, and a substantially straight inlet passage portion tangentially connected to the helical portion. A bypass passage is branched off from the inlet passage portion and connected to the helical portion. A rotary valve is arranged in the bypass passage and has an arm connected to a vacuum operated diaphragm apparatus. The rotary valve has a stop which is engageable with the arm. The arm is normally in engagement with the stop due to the spring force of a coil spring for retaining the rotary valve precisely at the maximum open position.

Abstract: A helically-shaped intake port comprising a helical portion formed around an intake valve, and a substantially straight inlet passage portion tangentially connected to the helical portion. A bypass passage is branched off from the inlet passage portion and connected to the helical portion. A slide valve is arranged in the bypass passage and controlled by an electronic control unit so that the opening area of the slide valve is proportional to the amount of air fed into the cylinder of the engine.

Abstract: A helically-shaped intake port comprising a helical portion formed around an intake valve and a substantially straight inlet passage portion tangentially connected to the helical portion. A bypass passage is branched off from the inlet passage portion and connected to the helical portion. A flow control valve is arranged in the bypass passage and actuated by a bellows. The flow control valve is opened when the amount of air fed into the cylinder of an engine is increased beyond a predetermined value.

Abstract: A helical type intake port is formed with the helical portion around an intake valve and the inlet portion tangentially contiguous to the helical portion.A bypass passage is provided in a cylinder head, which is branched off from the inlet portion and connected to an end portion of said helical portion. The flow in the bypass passage is controlled by a valve in response to the amount of air in the intake port so that a strong swirl flow with a slight flow resistance may be obtained at not only a low revolution and a low load, but also at a high revolution and a high load.

Abstract: A helical type intake port for an internal combustion engine. The system has a first sub-intake passageway and a second sub-intake passageway. The first sub-intake passageway is connected to a helical end of the intake passageway for generating a flow of air for suppression of the swirl effect in the helical end. The second sub-intake passageway is connected to a portion of the helical port located upstream of the helical end portion, for increasing the speed of flow of air directed to the helical end portion.

Abstract: In the manufacture of a bearing material containing an aluminum base alloy, one surface of a steel strip is washed and roughened; the aluminum base alloy is spread on the surface of the steel strip; and the aluminum base alloy and the steel strip are hot-rolled in the air to pressure-bond the former to the latter into a unitary structure. Prior to spreading the aluminum base alloy, an aluminum powder which well adheres to the steel strip may also be spread on the surface of the steel strip.

Abstract: A high compression type internal combustion engine comprising a cylinder head having a flat inner wall, and a piston having a flat top face. The flat inner wall and the flat top face form a squish area therebetween. A recess having a lung-shaped cross-section is formed in the cylinder head. A shallow groove is formed on the flat inner wall of the cylinder head so as to extend from the intake valve to the recess. An exhaust valve is arranged on the bottom of the recess. The squish area comprises a first squish area portion and a second squish area portion. The first squish area portion has an area which is about four times the area of the second squish area portion. A spark plug is arranged in the recess at a position near the first squish area portion and remote from the second squish area portion.

Abstract: A fuel injection type internal combustion engine comprising a cylinder head having a flat inner wall, and a piston having a flat top face. The flat inner wall and the flat top face form a squish area therebetween. A recess having a lung shaped cross-section is formed in the cylinder head. A shallow groove is formed on the flat inner wall of the cylinder head so as to extend from the intake valve to the recess. The exhaust valve is arranged on the bottom of the recess. A depression connected to the recess is formed on the shallow groove. The spark plug is arranged in the depression. The cylinder head has a portion located between the recess and the intake passage. A fuel injector is arranged in the intake passage. The nozzle of the fuel injector is directed to an inner wall portion of the intake passage, which is located near the recess.

Abstract: In an internal combustion engine, the combination of a cylinder head with a plane lower surface and a cavity, a piston with a plane upper surface and a cavity, the plane surfaces of the piston and the cylinder head cooperating to form a squish area on one side of the cylinder bore, and a spark plug protruding into the combustion chamber defined by the cavities so that its igniting tip lies substantially in the squish plane on the other side of the cylinder bore.

Abstract: An internal combustion engine having an auxiliary combustion chamber connected to only the main combustion chamber via a connecting passage. The engine comprises a first raised portion formed on the inner wall of the cylinder head, a second raised portion formed on the top face of the piston at a position opposite to the first raised portion with respect to the axis of the piston, and a third raised portion formed on the inner wall of the cylinder head above the second raised portion. A first flat squish area is formed between the flat peripheral top face of the piston and the flat bottom face of the first raised portion. A second spherical shell shape squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion. A recessed portion is formed on the top wall of the main combustion chamber at a position near the first raised portion. The open end of the connecting passage is arranged in the recessed portion.

Abstract: Helically-shaped intake port comprising a helical portion and an inlet passage portion which is tangentially connected to the helical portion and is slightly curved. The intake valve is arranged at the open outlet end of the helical portion. The upper wall of the helical portion extends to a helix terminating portion from the connecting position, and the inlet passage portion is connected to the helical portion. The height between the outlet open end and the upper wall of the helical portion, which is located at the helix terminating portion, is equal to or larger than the diameter of the outlet open end.

Abstract: A multi-cylinder internal combustion engine comprising a plurality of cylinders each having a helically-shaped intake port. The helically-shaped intake port comprises a helical portion having the outlet open end, and an inlet passage portion having an inlet open end and tangentially connected to the helical portion. The intake valve is arranged in the outlet open end. The engine further comprises a common connecting passage and a plurality of branch connecting passages each being in communication with the common connecting passage. Each of the branch connecting passages opens into the inlet open end of the corresponding helically-shaped intake port at a position near the upper wall of the helically-shaped intake port.

Abstract: An internal combustion engine comprising a first raised portion formed on the inner wall of the cylinder head, a second raised portion formed on the top face of the piston at a position opposite to the first raised portion with respect to the axis of the piston, and a third raised portion formed on the inner wall of the cylinder head above the second raised portion. A first flat squish area is formed between the flat peripheral top face of the piston and the flat bottom face of the first raised portion. A second spherical shell shaped squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion. The second raised portion has a front face which comprises a gently inclined front face portion and a steeply inclined front face portion. The gently inclined front face portion is arranged beneath the exhaust valve, and the steeply inclined front face portion is arranged beneath the intake valve.

Abstract: An internal combustion engine comprising a first raised portion formed on the inner wall of the cylinder head, a second raised portion formed on the top face of the piston at a position opposite to the first raised portion with respect to the axis of the piston, and a third raised portion formed on the inner wall of the cylinder head above the second raised portion. A first flat squish area is formed between the flat peripheral top face of the piston and flat bottom face of the first raised portion. A second spherical shell shaped squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion. A pair of spark plugs is arranged on the top face of the combustion chamber. One of the spark plugs is arranged in the vicinity of said first raised portion, and the other spark plug is arranged in the vicinity of said third raised portion.

Abstract: An internal combustion engine comprises a main combustion chamber and an auxiliary combustion chamber which are interconnected to each other via a connecting passage. The spark plug is arranged in the connecting passage. The engine further comprises a first raised portion formed on the inner wall of the cylinder head, a second raised portion formed on the top face of the piston at a position opposite to the first raised portion with respect to the axis of the piston, and a third raised portion formed on the inner wall of the cylinder head above the second raised portion. A first flat squish area is formed between the flat peripheral top face of the piston and the flat bottom face of the first raised portion. A second spherical shell shaped squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion. The axis of the connecting passage is located in the extension of the second squish area.

Abstract: An internal combustion engine comprises a first raised portion formed on the inner wall of the cylinder head, a second raised portion formed on the top face of the piston at a position opposite to the first raised portion with respect to the axis of the piston, and a third raised portion formed on the inner wall of the cylinder head above the second raised portion. A first flat squish area is formed between the flat peripheral top face of the piston and the flat bottom face of the first raised portion. A second spherical shell shape squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion.

Abstract: An internal combustion engine comprises a first raised portion formed on the inner wall of the cylinder head, a second raised portion formed on the top face of the piston at a position opposite to the first raised portion with respect to the axis of the piston, and a third raised portion formed on the inner wall of the cylinder head above the second raised portion. A first flat squish area is formed between the flat peripheral top face of the piston and the flat bottom face of the first raised portion. A second spherical shell shape squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion. A recess is formed on the top face of the combustion chamber and arranged on an extension of the second squish area. The spark plug is arranged in the recess.

Abstract: An internal combustion engine comprises a first raised portion formed on the inner wall of the cylinder head, a second raised portion formed on the top face of the piston at a position opposite to the first raised portion with respect to the axis of the piston, and a third raised portion formed on the inner wall of the cylinder head above the second raised portion. A first flat squish area is formed between the flat peripheral top face of the piston and the flat bottom face of the first raised portion. A second spherical shell shape squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion. The third raised portion has a steeply inclined side wall extending upwards from the ridge of the second raised portion. A depression having a vertically extending peripheral wall is formed in the central portion of the top face of the piston. The peripheral wall is aligned with the vertically extending side wall of the first raised portion.

Abstract: An internal combustion engine comprises a first raised portion formed on the inner wall of the cylinder head, a second raised portion formed on the top face of the piston at a position opposite to the first raised portion with respect to the axis of the piston, and a third raised portion formed on the inner wall of the cylinder head above the second raised portion. A first flat squish area is formed between the flat peripheral top face of the piston and the flat bottom face of the first raised portion. A second spherical shell shape squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion. A secondary throttle valve is arranged in the intake passage located downstream of the throttle valve of a carburetor. A secondary intake passage is branched off from the intake passage located between the secondary throttle valve and the throttle valve of the carburetor and opens into the intake port at a position near the intake valve.

Abstract: A high compression type internal combustion engine comprising a cylinder head having a flat inner wall, and a piston having a flat top face. The flat inner wall and the flat top face form a squish area therebetween. A recess having a lung shaped cross-section is formed in the cylinder head. A shallow groove is formed in the flat inner wall of the cylinder head so as to extend from the intake valve to the recess. The exhaust valve is arranged on the top of the recess. A depression connected to the recess is formed in the shallow groove. The spark plug is arranged in the depression.