Abstract: An internal combustion engine includes a crankcase that defines a crank chamber, a crankshaft that has a crank housed in the crank chamber and is rotatably supported on the crankcase, a cylinder block that is joined to the crankcase and defines a plurality of cylinders in a horizontally-opposed arrangement, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that extends through the crankcase from an upper face of the crankcase, is made to face a trajectory of the to-be-detected body, and generates a pulse signal in response to movement of the to-be-detected body. Thus, in a so-called horizontally-opposed internal combustion engine, a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision is provided.

Abstract: An internal combustion engine includes a crankshaft that is rotatably supported on the crankcase, a cylinder block that is joined to the crankcase and defines a plurality of cylinders in a V-type arrangement in which the cylinders are disposed above a virtual horizontal plane including a rotational axis of the crankshaft and intersect each other at a bank angle, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that is mounted from an outside at a position, lower than the virtual horizontal plane, of a front face of the crankcase that receives air flow, is made to face a trajectory of the to-be-detected body, and generates a pulse signal in response to movement of the to-be-detected body. Thereby provided is a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision in a so-called V-type internal combustion engine.

Abstract: An internal combustion engine includes a crankcase that rotatably supports a crankshaft, a case cover that liquid-tightly covers a side of the crankcase, a cylinder block that is joined to the crankcase and divides a plurality of cylinders in a V-type arrangement in which the cylinders are disposed above a virtual horizontal plane including a rotational axis of the crankshaft and intersect each other at a bank angle, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that is mounted from the outside on the crankcase at a position higher than the virtual horizontal plane and is made to face a trajectory of the to-be-detected body to generate a pulse signal in response to movement of the to-be-detected body. This provides, in a so-called V-type internal combustion engine, a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision.

Abstract: There is provided an internal combustion engine in which oil can be kept in an oil passageway when oil is supplied, so that the time required to supply oil can be reduced. In an internal combustion engine in which an oil supply inlet for replenishing, with oil, an oil pan reservoir chamber disposed in a lower portion of a crankcase extends obliquely downwardly from an oil supply port at an upper end thereof, the oil pan reservoir chamber has an oil pan inlet port disposed in a position offset from a vertical plane, including the oblique oil supply inlet, and a horizontal oil supply passageway bent and extending substantially horizontally from a lower end of the oil supply inlet is connected to the oil pan inlet port.

Abstract: An internal combustion engine includes a crankshaft that is rotatably supported on a crankcase via a pair of bearings and has a crank housed in a crank chamber, a to-be-detected body that is housed in the crank chamber and is supported on the crankshaft, and a detection sensor that is made to face a trajectory of the to-be-detected body and detects movement of the to-be-detected body to generate a pulse signal. The to-be-detected body is disposed on an inner side of the bearing. Thus, an internal combustion engine is provided that enables a crank angle to be detected in a state in which vibration and flexure occurring in a crankshaft are suppressed.

Abstract: An internal combustion engine includes a crankcase that defines a crank chamber, a crankshaft that has a crank housed in the crank chamber and is rotatably supported on the crankcase, a cylinder block that is joined to the crankcase and defines a plurality of cylinders in a horizontally-opposed arrangement, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that extends through the crankcase from an upper face of the crankcase, is made to face a trajectory of the to-be-detected body, and generates a pulse signal in response to movement of the to-be-detected body. Thus, in a so-called horizontally-opposed internal combustion engine, a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision is provided.

Abstract: An internal combustion engine includes a crankcase that rotatably supports a crankshaft, a case cover that liquid-tightly covers a side of the crankcase, a cylinder block that is joined to the crankcase and divides a plurality of cylinders in a V-type arrangement in which the cylinders are disposed above a virtual horizontal plane including a rotational axis of the crankshaft and intersect each other at a bank angle, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that is mounted from the outside on the crankcase at a position higher than the virtual horizontal plane and is made to face a trajectory of the to-be-detected body to generate a pulse signal in response to movement of the to-be-detected body. This provides, in a so-called V-type internal combustion engine, a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision.

Abstract: An internal combustion engine includes a crankshaft that is rotatably supported on a crankcase via a pair of bearings and has a crank housed in a crank chamber, a to-be-detected body that is housed in the crank chamber and is supported on the crankshaft, and a detection sensor that is made to face a trajectory of the to-be-detected body and detects movement of the to-be-detected body to generate a pulse signal. The to-be-detected body is disposed on an inner side of the bearing. Thus, an internal combustion engine is provided that enables a crank angle to be detected in a state in which vibration and flexure occurring in a crankshaft are suppressed.

Abstract: An internal combustion engine includes a crankshaft that is rotatably supported on the crankcase, a cylinder block that is joined to the crankcase and defines a plurality of cylinders in a V-type arrangement in which the cylinders are disposed above a virtual horizontal plane including a rotational axis of the crankshaft and intersect each other at a bank angle, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that is mounted from an outside at a position, lower than the virtual horizontal plane, of a front face of the crankcase that receives air flow, is made to face a trajectory of the to-be-detected body, and generates a pulse signal in response to movement of the to-be-detected body. Thereby provided is a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision in a so-called V-type internal combustion engine.

Abstract: There is provided an internal combustion engine in which oil can be kept in an oil passageway when oil is supplied, so that the time required to supply oil can be reduced. In an internal combustion engine in which an oil supply inlet for replenishing, with oil, an oil pan reservoir chamber disposed in a lower portion of a crankcase extends obliquely downwardly from an oil supply port at an upper end thereof, the oil pan reservoir chamber has an oil pan inlet port disposed in a position offset from a vertical plane, including the oblique oil supply inlet, and a horizontal oil supply passageway bent and extending substantially horizontally from a lower end of the oil supply inlet is connected to the oil pan inlet port.

Abstract: A valve operating apparatus for use in an internal combustion engine includes an intake cam 38, an intake rocker arm 33 rotatable about a rotational shaft 35 and driven by the intake cam 38, and an intake valve 40 pushed by a pusher 70 of the intake rocker arm 33, the internal combustion engine has a cylinder assembly 12L lying horizontally, and the intake rocker arm 33 has a weight 67 adjusting the center of gravity of the rocker arm 33 to position the pusher 70 above the rotational shaft 35 while the intake cam 38 is held out of abutting contact with the intake rocker arm 33.

Abstract: An exhaust emission control device for an internal combustion engine including multiple reed valve chambers which are provided to cylinder head portions of a multi-cylinder engine. The reed valve chambers are formed by covering recessed portions in the cylinder head portion with reed valve covers. Upstream sides of the reed valve chambers communicate with the atmosphere via a secondary air supply pipe. Downstream sides of the reed valve chambers communicate with exhaust ports via communication passages provided to the cylinder head portion. The reed valves are interposed between the upstream sides and the downstream sides of the reed valve chambers, and are opened by exhaust pulsation pressure. In the cylinder head portion, the multiple reed valve chambers are disposed with spaces therebetween. The reed valve covers communicate individually with the secondary air supply pipe, and the reed valve covers are connected in series by the secondary air supply pipe.

Abstract: A valve operating apparatus for use in an internal combustion engine includes an intake cam 38, an intake rocker arm 33 rotatable about a rotational shaft 35 and driven by the intake cam 38, and an intake valve 40 pushed by a pusher 70 of the intake rocker arm 33, the internal combustion engine has a cylinder assembly 12L lying horizontally, and the intake rocker arm 33 has a weight 67 adjusting the center of gravity of the rocker arm 33 to position the pusher 70 above the rotational shaft 35 while the intake cam 38 is held out of abutting contact with the intake rocker arm 33.

Abstract: An exhaust emission control device for an internal combustion engine including multiple reed valve chambers which are provided to cylinder head portions of a multi-cylinder engine. The reed valve chambers are formed by covering recessed portions in the cylinder head portion with reed valve covers. Upstream sides of the reed valve chambers communicate with the atmosphere via a secondary air supply pipe. Downstream sides of the reed valve chambers communicate with exhaust ports via communication passages provided to the cylinder head portion. The reed valves are interposed between the upstream sides and the downstream sides of the reed valve chambers, and are opened by exhaust pulsation pressure. In the cylinder head portion, the multiple reed valve chambers are disposed with spaces therebetween. The reed valve covers communicate individually with the secondary air supply pipe, and the reed valve covers are connected in series by the secondary air supply pipe.