Abstract: A single cylinder engine includes an engine body having a combustion chamber, an intake opening and an exhaust opening which face toward the combustion chamber, an intake passage in communication with the combustion chamber through the intake opening, and an exhaust passage in communication with the combustion chamber through the exhaust opening, an intake valve that opens and closes the intake opening, an exhaust valve that opens and closes the exhaust opening, an injector that injects a fuel toward the intake opening and into the intake passage, a ternary catalyst provided in the exhaust passage, and an engine control unit (ECU) that performs a decelerated operation to selectively execute a cycle for injection of a fuel from the injector, a quantity of which makes an air-fuel ratio in the combustion chamber substantially equal to a theoretical air fuel ratio, and a cycle for inhibition of fuel injection from the injector.

Abstract: An internal combustion engine includes a cylinder head, a cylinder having an opposed surface opposed to the cylinder head and including a water jacket, which is concave in an axial direction of the cylinder, and a piston provided in the cylinder. An oil ring is provided on the piston on a side that is farthest from the cylinder head. At least a portion between a cylinder inner surface and the water jacket in the cylinder is made of a material having a higher thermal conductivity than that of iron. A bottom wall of the water jacket is positioned in the cylinder axial direction between the opposed surface of the cylinder and a lower end of the oil ring when the piston is disposed at a top dead center position.

Abstract: A single cylinder engine includes an engine body having a combustion chamber, an intake opening and an exhaust opening which face toward the combustion chamber, an intake passage in communication with the combustion chamber through the intake opening, and an exhaust passage in communication with the combustion chamber through the exhaust opening, an intake valve that opens and closes the intake opening, an exhaust valve that opens and closes the exhaust opening, an injector that injects a fuel toward the intake opening and into the intake passage, a ternary catalyst provided in the exhaust passage, and an engine control unit (ECU) that performs a decelerated operation to selectively execute a cycle for injection of a fuel from the injector, a quantity of which makes an air-fuel ratio in the combustion chamber substantially equal to a theoretical air fuel ratio, and a cycle for inhibition of fuel injection from the injector.

Abstract: An internal combustion engine includes a cylinder head, a cylinder having an opposed surface opposed to the cylinder head and including a water jacket, which is concave in an axial direction of the cylinder, and apiston provided in the cylinder. An oil ring is provided on the piston on a side that is farthest from the cylinder head. At least a portion between a cylinder inner surface and the water jacket in the cylinder is made of a material having a higher thermal conductivity than that of iron. A bottom wall of the water jacket is positioned in the cylinder axial direction between the opposed surface of the cylinder and a lower end of the oil ring when the piston is disposed at a top dead center position.

Abstract: An internal combustion engine includes a cylinder having a cylinder inner surface, a cylinder head that cooperates with the cylinder inner surface to define a combustion chamber and has a head inner surface including an intake opening through which an intake gas is introduced into the combustion chamber, an intake valve that opens and closes the intake opening, an ignition plug provided on the cylinder head, and an intake drifting mechanism that causes the intake gas to drift toward an axis of the cylinder in the intake opening and generates a vortex flow in the combustion chamber. When the intake valve is opened, a minimum gap between the intake valve and the head inner surface is equal to or larger than a gap between the intake valve and the cylinder inner surface in a diametrical direction of the cylinder.

Abstract: An internal combustion engine includes an engine body including a cylinder that defines a combustion chamber, an intake opening that faces the combustion chamber, and an intake passage in communication with the combustion chamber through the intake opening, a piston provided in the cylinder, an intake valve that opens and closes the intake opening, a throttle valve provided in the intake passage, and an injector that injects fuel between the throttle valve in the intake passage and the intake opening. A ratio of a volume of the portion that extends from the throttle valve in the intake passage to the intake opening, to a stroke volume of the cylinder is at most approximately 0.61. The time period in which fuel injection from the injector is terminated during an idling operation is set within a period of time after one intake stroke has been completed and before the next intake stroke is begun.

Abstract: An engine having a crank case splitted into upper and lower crank cases, and including a crank shaft and a transmission drive shaft disposed on the split plane between the upper crank case and the lower crank case and a transmission main shaft carried by either one of the upper or lower crank case. The length and the size of the engine can be reduced by the arrangement according to the invention, and a starter motor, a transmission drum and balancers can be arranged efficiently to save space required for mounting the engine.

Abstract: Two embodiments of motorcycles having improved exhaust systems. In each embodiment, the motorcycle includes a V-type engine and the exhaust system provides substantially equal length exhaust pipes that merge into a common exhaust outlet and which are disposed beneath the clutch and on the opposite side of the engine from the generator. In addition, one embodiment discloses an oil filter that is disposed above the clutch so as to be protected from the heat of the exhaust pipes by the clutch.

Abstract: Two embodiments of overhead camshaft internal combustion engines that provide a compact arrangement through a simplified bearing and thrust arrangement for the camshafts. In accordance with each embodiment, one of the lobes of the camshafts are positioned at the ends of the camshafts and the camshafts are axially located by thrust surfaces formed between pairs of lobes. In one embodiment of the invention, the camshaft operates three valves per cylinder. In this embodiment, the fastening means for affixing the cylinder head to the cylinder block lies beneath the camshafts and the camshafts have openings so that the fastening means may be tightened without necessitating removal of the camshafts.

Abstract: An improved induction system for a V type engine that improves both charging and combustion efficiency. The engine includes an induction system for each cylinder barrel that includes a pair of intake valves and respective intake passages that have a common inlet. One of the intake passages is curved and an auxiliary intake passage extends through the cylinder head and terminates at an auxiliary intake port that is disposed at one side of the main intake port in proximity to the cylinder barrel for generating a swirl to the intake charge. A plenum chamber is positioned in the V of the engine and defines two separate chambers each of which communicates with a respective one of the auxiliary intake passages.

Abstract: A balancing device for a V-type internal combustion engine in which the angle of the V is not equal to 90.degree.. The balancing device comprises a shaft that is rotatable about an axis parallel to the axis of the crankshaft and which is driven at the same speed as the crankshaft but in the opposite direction. A first balancing mass is affixed to this shaft for balancing the first order inertial forces of the reciprocating masses of the cylinders and a pair of masses disposed on opposite sides of the first mass for balancing the couples generated by the offset of the connecting rods of the cylinders.

Abstract: An improved induction system for a V type engine that improves both charging and combustion efficiency. The engine includes an induction system for each cylinder barrel that includes a pair of intake valves and respective intake passages that have a common inlet. One of the intake passages is curved and an auxiliary intake passage extends through the cylinder head and terminates at an auxiliary intake port that is disposed at one side of the main intake port in proximity to the cylinder barrel for generating a swirl to the intake charge. A plenum chamber is position in the V of the engine and defines two separate chambers each of which communicates with a respective one of the auxiliary intake passages.

Abstract: An improved cylinder head fastening arrangement for an internal combustion engine that permits location of overhead cam shafts directly over the cylinder head fasteners. The cam shafts are formed with access openings that extend through them which permits a tool to be passed for tightening of the cylinder head fasteners without removal of the cam shaft.

Abstract: An improved cylinder head fastening arrangement for an internal combustion engine that permits location of overhead cam shafts directly over the cylinder head fasteners. The cam shafts are formed with access openings that extend through them which permit a tool to be passed for tightening of the cylinder head fasteners without removal of the cam shaft.