Abstract: A saddled vehicle includes: a fuel injection valve mounted in a cylinder head from one side surface of the cylinder head and injecting fuel toward a combustion chamber; and a fuel pump that supplies fuel to the fuel injection valve in response to a generated pump pressure. The fuel pump is disposed in a space between main frames and a down frame and in the one side surface of the cylinder head. Accordingly, there is provided a layout of the fuel pump capable of sufficiently protecting the fuel pump without a need to restrict a position of an internal combustion engine.

Abstract: An internal combustion engine includes an auxiliary chamber bulkhead, the auxiliary chamber bulkhead including: a peripheral wall portion that is inserted in a vertical hole extending from a combustion chamber along a reference axis and that is in contact with an inner wall of the vertical hole about the reference axis; and a bottom wall portion that is continuous from the peripheral wall portion and that bulges from the vertical hole toward the combustion chamber, the peripheral wall portion and the bottom wall portion defining an auxiliary chamber that communicates with the combustion chamber. An ignition plug is disposed above the peripheral wall portion along the reference axis. A fuel injection valve is disposed in a position inclined with respect to the reference axis toward an opening formed in an inner surface of the peripheral wall portion.

Abstract: An in-cylinder injection engine includes: a cylinder head that includes a gasket surface stacked on a seating face of a cylinder block and defines a combustion chamber between a piston and a ceiling surface gradually receding from an imaginary plane including the gasket surface in going toward a center of the cylinder head; two intake ports disposed side by side and opened in the ceiling surface of the cylinder head; and a fuel injection valve mounted to the cylinder head and having an injection port facing the combustion chamber at a position between an opening of the intake port and the gasket surface. The intake port is formed to have a shape of introducing an airflow laterally into the combustion chamber along the imaginary plane. Accordingly, the in-cylinder injection engine can reduce attachment of injected fuel to a wall surface of a cylinder bore.

Abstract: An internal combustion engine includes an auxiliary chamber bulkhead, the auxiliary chamber bulkhead including: a peripheral wall portion that is inserted in a vertical hole extending from a combustion chamber along a reference axis and that is in contact with an inner wall of the vertical hole about the reference axis; and a bottom wall portion that is continuous from the peripheral wall portion and that bulges from the vertical hole toward the combustion chamber, the peripheral wall portion and the bottom wall portion defining an auxiliary chamber that communicates with the combustion chamber. An ignition plug is disposed above the peripheral wall portion along the reference axis. A fuel injection valve is disposed in a position inclined with respect to the reference axis toward an opening formed in an inner surface of the peripheral wall portion.

Abstract: A saddled vehicle includes: a fuel injection valve mounted in a cylinder head from one side surface of the cylinder head and injecting fuel toward a combustion chamber; and a fuel pump that supplies fuel to the fuel injection valve in response to a generated pump pressure. The fuel pump is disposed in a space between main frames and a down frame and in the one side surface of the cylinder head. Accordingly, there is provided a layout of the fuel pump capable of sufficiently protecting the fuel pump without a need to restrict a position of an internal combustion engine.

Abstract: A lubricating device for a power unit includes an oil pan, an oil tank being separated from the oil pan, a scavenging pump for circulating the received oil of the oil pan to the oil tank, and a feed pump to feeding oil stored in the oil tank to the engine and the transmission, wherein an oil reservoir for storing a certain amount of oil to immerse a lower part of a clutch that connects and disconnects a transmission route between the engine and the transmission is provided in a power unit case, and a first overflow passage is provided in the oil tank such that when the stored oil in the oil tank is increased beyond a first level, the first overflow passage allows the increased oil to overflow into the oil reservoir side.

Abstract: An engine body includes a crankcase with a crank chamber therein, a cylinder block attached to the crankcase, and a breather passage which selectively permits fluid communication between the crank chamber and an area outside of the crank chamber. The engine body includes a one-way valve between the crank chamber and the breather passage, which allows a one-way flow of gases from the crank chamber to the breather passage. The one-way valve is pressure-operated and is operatively attached to a side wall of the engine body proximate a cylinder sleeve. The one-way valve may be mounted in a mounting window in a side wall of the crankcase, and a timing chamber may function as the breather passage. In an illustrative embodiment, the one-way valve includes a base plate having a valve hole formed therein, and a flexible reed valve plate with one end affixed to the base plate.

Abstract: An ignition plug cooling device of a vehicle engine for efficiently cooling the ignition plugs while increasing the freedom in the arrangement of the ignition plugs. A vehicle engine includes a first ignition plug and a second ignition plug for making respective electrodes thereof face a combustion chamber and are mounted on a cylinder head. An air flow passage through which a flow of air passes and a cooling oil chamber through which lubrication oil for the engine passes are formed in the cylinder head. The first ignition plug is arranged in the air flow passage to enable a cooling of the first ignition plug by the flow of air which passes through the air flow passage. The second ignition plug is arranged adjacent to the cooling oil chamber to enable a cooling of an area around the second ignition plug by oil which passes through the cooling oil chamber.

Abstract: A lubricating device for a power unit includes an oil pan, an oil tank being separated from the oil pan, a scavenging pump for circulating the received oil of the oil pan to the oil tank, and a feed pump to feeding oil stored in the oil tank to the engine and the transmission, wherein an oil reservoir for storing a certain amount of oil to immerse a lower part of a clutch that connects and disconnects a transmission route between the engine and the transmission is provided in a power unit case, and a first overflow passage is provided in the oil tank such that when the stored oil in the oil tank is increased beyond a first level, the first overflow passage allows the increased oil to overflow into the oil reservoir side.

Abstract: A vehicle engine in which a water temperature sensor can be protected against debris or foreign matter such as earth and sand, flying stones, etc., from impacting the temperature sensor without taking any protective measure for exclusive use. A vehicle engine includes a head portion of the cylinder fitted with a water temperature sensor for detecting water temperature in a water jacket. The head portion of the cylinder is provided on one side thereof with a sensor mounting hole opening directly under an upstream end opening portion of an intake port. The water temperature sensor is mounted in the sensor mounting hole. Further, the head portion of the cylinder is formed with a left-right pair of hanger bosses which are opposed to each other, with the water temperature sensor therebetween. Engine hanger brackets extend from the body frame and are firmly attached to the hanger bosses.

Abstract: A vehicle engine includes the crankcase for supporting thereon the crankshaft, the input shaft and the output shaft, with the crankcase being composed of a left case half and a right case half which are joined to each other at a plane orthogonal to the axis of the crankshaft. A starter motor together with a speed sensor, for detecting the vehicle speed from the rotation of a gear in a transmission, are mounted to an upper surface of the crankcase. The starter motor is arranged at a portion, just above the input shaft, of the upper surface of the crankcase, while the speed sensor for detecting the rotation of a gear on the output shaft is arranged at a portion, just above the output shaft, of the upper surface of the crankcase. The crankcase is formed with a raised wall for covering one side surface of the speed sensor.

Abstract: An engine body includes a crankcase with a crank chamber therein, a cylinder block attached to the crankcase, and a breather passage which selectively permits fluid communication between the crank chamber and an area outside of the crank chamber. The engine body includes a one-way valve between the crank chamber and the breather passage, which allows a one-way flow of gases from the crank chamber to the breather passage. The one-way valve is pressure-operated and is operatively attached to a side wall of the engine body proximate a cylinder sleeve. The one-way valve may be mounted in a mounting window in a side wall of the crankcase, and a timing chamber may function as the breather passage. In an illustrative embodiment, the one-way valve includes a base plate having a valve hole formed therein, and a flexible reed valve plate with one end affixed to the base plate.

Abstract: An ignition plug cooling device of a vehicle engine for efficiently cooling the ignition plugs while increasing the freedom in the arrangement of the ignition plugs. A vehicle engine includes a first ignition plug and a second ignition plug for making respective electrodes thereof face a combustion chamber and are mounted on a cylinder head. An air flow passage through which a flow of air passes and a cooling oil chamber through which lubrication oil for the engine passes are formed in the cylinder head. The first ignition plug is arranged in the air flow passage to enable a cooling of the first ignition plug by the flow of air which passes through the air flow passage. The second ignition plug is arranged adjacent to the cooling oil chamber to enable a cooling of an area around the second ignition plug by oil which passes through the cooling oil chamber.

Abstract: A shift drum apparatus is reduced in weight relative to conventional shift drums. The shift drum includes a shift fork, a shift drum main body, and a lid member. The shift fork is slidably mounted on a shift fork support shaft. The shift fork changes a gear position of a transmission mechanism. The shift drum main body is formed into a hollow cylindrical shape. The shift drum main body has an end face on a first side thereof in a cylindrical axis direction that is open to form an opening portion. The shift drum main body further includes a cam groove formed on an outer circumferential surface thereof. An end portion of the shift fork is fitted in this cam groove to allow the shift fork to slide. The lid member is disc-shaped and mounted by being press-fitted in the opening portion of the shift drum main body.

Abstract: A vehicle engine in which a water temperature sensor can be protected against debris or foreign matter such as earth and sand, flying stones, etc., from impacting the temperature sensor without taking any protective measure for exclusive use. A vehicle engine includes a head portion of the cylinder fitted with a water temperature sensor for detecting water temperature in a water jacket. The head portion of the cylinder is provided on one side thereof with a sensor mounting hole opening directly under an upstream end opening portion of an intake port. The water temperature sensor is mounted in the sensor mounting hole. Further, the head portion of the cylinder is formed with a left-right pair of hanger bosses which are opposed to each other, with the water temperature sensor therebetween. Engine hanger brackets extend from the body frame and are firmly attached to the hanger bosses.

Abstract: A vehicle engine includes the crankcase for supporting thereon the crankshaft, the input shaft and the output shaft, with the crankcase being composed of a left case half and a right case half which are joined to each other at a plane orthogonal to the axis of the crankshaft. A starter motor together with a speed sensor, for detecting the vehicle speed from the rotation of a gear in a transmission, are mounted to an upper surface of the crankcase. The starter motor is arranged at a portion, just above the input shaft, of the upper surface of the crankcase, while the speed sensor for detecting the rotation of a gear on the output shaft is arranged at a portion, just above the output shaft, of the upper surface of the crankcase. The crankcase is formed with a raised wall for covering one side surface of the speed sensor.

Abstract: A splash guard mechanism of a gear position sensor for a motorcycle protects the gear position sensor without providing a special cover. In an engine of a motorcycle where a gear position sensor that senses a shift stage selected by a shift drum protrudes sideways in the vicinity of a driving sprocket for driving a rear wheel by a crankcase that holds a crankshaft, a splash guard mechanism of the gear position sensor is configured by a splash guard formed on a sprocket cover that covers the driving sprocket from the side and arranged between the gear position sensor and the driving sprocket, and a rib protrudes from the reverse side of the driving sprocket with the gear position sensor between them in the crankcase.

Abstract: A splash guard mechanism of a gear position sensor for a motorcycle protects the gear position sensor without providing a special cover. In an engine of a motorcycle where a gear position sensor that senses a shift stage selected by a shift drum protrudes sideways in the vicinity of a driving sprocket for driving a rear wheel by a crankcase that holds a crankshaft, a splash guard mechanism of the gear position sensor is configured by a splash guard formed on a sprocket cover that covers the driving sprocket from the side and arranged between the gear position sensor and the driving sprocket, and a rib protrudes from the reverse side of the driving sprocket with the gear position sensor between them in the crankcase.

Abstract: A shift drum apparatus is reduced in weight relative to conventional shift drums. The shift drum includes a shift fork, a shift drum main body, and a lid member. The shift fork is slidably mounted on a shift fork support shaft. The shift fork changes a gear position of a transmission mechanism. The shift drum main body is formed into a hollow cylindrical shape. The shift drum main body has an end face on a first side thereof in a cylindrical axis direction that is open to form an opening portion. The shift drum main body further includes a cam groove formed on an outer circumferential surface thereof. An end portion of the shift fork is fitted in this cam groove to allow the shift fork to slide. The lid member is disc-shaped and mounted by being press-fitted in the opening portion of the shift drum main body.

Abstract: A shaft actuator for a transmission. A first electromagnetic solenoid is provided to operate a shifting mechanism of the transmission to a first shifted position. A second electromagnetic solenoid is provided to operate the shifting mechanism to a second shifted position. A neutral operation member is mounted on the shifting mechanism to bring the shifting mechanism to a neutral position lying between the first shifted position and the second shifted position. A neutral limitation member can move to a first position, where the neutral operation member is permitted to be operated to the first shifted position and to the second shifted position, and to a second position, where the neutral operation member is brought to the neutral position. An electromagnetic solenoid for neutral can bring the neutral limitation member to the second position.