Abstract: A multicylinder engine for a motorcycle includes a valve actuation mechanism having a hydraulically-operated valve pausing mechanism for holding at least one of an intake valve and an exhaust valve of selected cylinders in a suspended state. The valve actuation mechanism operates the intake valve and the exhaust valve, and controls flow of oil through an oil passage which introduces working oil to the valve pausing mechanism from a hydraulic-pressure control device. Air-bleeding holes are formed in the cylinder head. The air-bleeding holes are fluidly connected with portions of the oil passages that are located at a highest level in the oil passages while the motorcycle is parked in an inclined state with its side stand down.

Abstract: A simpler configuration of a mechanism for stopping intake/exhaust valves opened/closed by a valve opening/closing mechanism of a rocker arm. An engine E includes an exhaust valve for opening/closing an exhaust port of an exhaust path with a first exhaust valve spring for energizing the exhaust valve in a valve closing direction. An exhaust valve drive cam is rotated in correspondence with the rotation of an engine crankshaft. A rocker arm is swingably provided between the exhaust valve and the exhaust valve drive cam with one end that abuts on the exhaust valve drive cam being pressed according to rotation of the exhaust valve drive cam and swinging to press the exhaust valve by a press member at the other end to move to the open side. An exhaust valve stopping mechanism is provided between the press member of the rocker arm and the exhaust valve.

Abstract: An air intake control system is provided for an internal combustion engine of a vehicle. The control system includes an intake port of a cylinder head for an engine main body, a throttle body having a throttle valve and connected to the intake port, an electric actuator having an electric motor and arranged on the throttle body to drive open or close the throttle valve, and a connector disposed on a housing of the electric actuator in a position facing toward one axial end of a crankshaft. The connector is provided in order to connect to an outside conductor to the electric motor of the electric actuator. The resulting configuration facilitates the work to connecting the outside conductor to the connector.

Abstract: In a multi-cylinder internal combustion engine, a hydraulic valve rest mechanism is mounted on a valve operating device, which performs open-close driving of an engine valve which is arranged in a cylinder head of an engine body having a plurality of cylinders in an openable-and-closable manner. The hydraulic valve rest mechanism is operated with an oil pressure that is controlled by a hydraulic control device so as to close and rest engine valves of a plurality of cylinders for bringing the cylinders into a rest state Therefore, the miniaturization of the multi-cylinder internal combustion engine along an axis of a crankshaft and can shorten a length of an oil passage which connects a hydraulic valve rest mechanism and a hydraulic control device. A hydraulic control device is arranged on an engine body directly above a portion thereof corresponding to a cylinder that is expected to assume a cylinder rest state.

Abstract: An electronic throttle control device in a internal combustion engine for a vehicle can be improved in maintainability and can be reduced in size. An electronic throttle control device in a V-type internal combustion engine for a vehicle has a fuel injection valve and throttle valves in an intake passage. A throttle driving motor controls the opening angle of each throttle valve according to the amount of operation of a throttle grip performed by an operator of the vehicle. The throttle driving motor is located outside a region surrounded by the throttle bodies that are respectively connected to all of intake ports as viewed in plan.

Abstract: A cooling control unit for a water-cooled multi-cylinder internal combustion engine having a cylinder deactivation mechanism for controlling the flow of coolant to prevent the internal combustion engine from being incompletely warmed up when the internal combustion engine returns to its operating condition with all of the cylinders being activated. A communicating passage communicates with a normally activated cylinder coolant jacket as a coolant passage formed for normally activated cylinders and a deactivation-programmed cylinder water jacket as a coolant passage formed for the deactivation-programmed cylinders to communicate with each other, and through which the coolant flows. A bypass passage diverges from the communicating passage and bypasses the deactivation-programmed cylinder coolant jacket. A diversion control valve is provided in a diversion section where the bypass passage diverges from the communication passage.

Abstract: In a V-type engine for a vehicle, in which a hydraulic valve rest mechanism which selectively holds at least one of an intake valve and an exhaust valve corresponding to a part of plural cylinders in a valve-closed rest state in correspondence with a vehicle running status is provided in a valve actuation unit, and a hydraulic controller which controls hydraulic pressure of the valve rest mechanism is provided in a main engine body, to reduce the distance of oil passage from the hydraulic controller to the hydraulic valve rest mechanism and simplify the structure of the oil passage. A hydraulic controller is provided on at least one side surface of a cylinder head, and may be generally oriented along a line which is substantially parallel to a central axis of a cylinder bore.

Abstract: An engine includes engine valves disposed on intake and exhaust sides of a combustion chambers with a valve operating device for opening and closing the engine valves and an engine valve disabling mechanism for disabling opening and closing movement of the engine valves in response to hydraulic pressure. An oil pump is disposed in a lower portion of the crankcase, for supplying hydraulic pressure to the engine valve disabling mechanism. A hydraulic pressure control valve controls the supply of hydraulic pressure to the engine valve disabling mechanism depending on a vehicle operating state. An oil passage extends to the hydraulic pressure control valve and can easily be formed without affecting mounts for functional components. A pipe for delivering working oil from the lower portion of the crankcase to the hydraulic pressure control valve is disposed on a front surface of the engine.

Abstract: In a variable valve timing mechanism, a valve-lifting cam member is fitted, slidably in the circumferential direction, onto a camshaft that is driven to rotate in synchronization with a crankshaft of a four-stroke cycle internal combustion engine. An eccentric collar is set between a driving collar fixed on the camshaft and the valve-lifting cam member. A driving projection is formed in the driving collar and engages with one of sandwiching portions of the eccentric collar. A driven protrusion is formed in the valve-lifting cam member and engages with another one of the sandwiching portions of the eccentric collar. A linkage mechanism includes the eccentric collar, the drive, and the driven protrusions. The variable valve timing mechanism adjusts the timing of opening and closing of the valve while the rotational phase of the valve-lifting cam member is cyclically varied relative to the camshaft by the eccentricity of the eccentric collar.

Abstract: A V-type vehicle engine includes a main engine body with a front bank with a rear bank defining a V-type structure. A plurality of valve actuation units are respectively located in valve chambers in the front bank and the rear bank, to minimize the size of a cylinder head and a cylinder head cover in at least one of the front bank and the rear bank. A first valve actuation unit, with a double overhead camshaft structure having intake-side and exhaust-side camshafts individually corresponding to the intake valve and the exhaust valve, is located in a valve chamber in one of the front bank and the rear bank. A second valve actuation unit, having a common single camshaft for the intake valve and the exhaust valve, is located in a valve chamber in the other one of the front bank and the rear bank.

Abstract: In a multi-cylinder engine provided with a cylinder pausing function, a hydraulically-operated valve-pausing mechanism is capable of selectively suspending operation of at least one intake or exhaust valve of one or more selected cylinders, depending on engine operating conditions, such that the suspended valve is temporarily held in a closed state. A hydraulic-pressure control device, for controlling hydraulic pressure supplied to the valve-pausing mechanism, is disposed on an engine body so as to minimize an amount of protrusion of the hydraulic-pressure control device from the engine body, while situating the hydraulic-pressure control device near the valve-pausing mechanism. A recess portion is formed on an external surface of a cylinder head or a head cover, and the hydraulic-pressure control device is disposed on the engine such that at least part of the hydraulic-pressure control device is accommodated in the recess portion.

Abstract: A multicylinder internal combustion engine, which can simplify its control and is advantageous against thermal loads or vibrations includes a cylinder head with intake valves and exhaust valves arranged therein. Valve actuators are provided for openably operating the intake valves and exhaust valves, respectively. A cylinder head cover forms, in combination with the cylinder head, a valve actuator chamber with the valve actuators accommodated therein. At least some of the valve actuators are deactivatable to disable their corresponding cylinders. The multicylinder internal combustion engine is a V-shaped internal combustion engine provided with a front bank and rear bank. The cylinders on opposite ends in a direction of a crankshaft are set as full-time operating cylinders.

Abstract: An engine includes engine valves disposed on intake and exhaust sides of a combustion chambers with a valve operating device for opening and closing the engine valves and an engine valve disabling mechanism for disabling opening and closing movement of the engine valves in response to hydraulic pressure. An oil pump is disposed in a lower portion of the crankcase, for supplying hydraulic pressure to the engine valve disabling mechanism. A hydraulic pressure control valve controls the supply of hydraulic pressure to the engine valve disabling mechanism depending on a vehicle operating state. An oil passage extends to the hydraulic pressure control valve and can easily be formed without affecting mounts for functional components. A pipe for delivering working oil from the lower portion of the crankcase to the hydraulic pressure control valve is disposed on a front surface of the engine.

Abstract: A cooling control unit for a water-cooled multi-cylinder internal combustion engine having a cylinder deactivation mechanism for controlling the flow of coolant to prevent the internal combustion engine from being incompletely warmed up when the internal combustion engine returns to its operating condition with all of the cylinders being activated. A communicating passage communicates with a normally activated cylinder coolant jacket as a coolant passage formed for normally activated cylinders and a deactivation-programmed cylinder water jacket as a coolant passage formed for the deactivation-programmed cylinders to communicate with each other, and through which the coolant flows. A bypass passage diverges from the communicating passage and bypasses the deactivation-programmed cylinder coolant jacket. A diversion control valve is provided in a diversion section where the bypass passage diverges from the communication passage.

Abstract: In a multi-cylinder engine provided with a cylinder pausing function, a hydraulically-operated valve-pausing mechanism is capable of selectively suspending operation of at least one intake or exhaust valve of one or more selected cylinders, depending on engine operating conditions, such that the suspended valve is temporarily held in a closed state. A hydraulic-pressure control device, for controlling hydraulic pressure supplied to the valve-pausing mechanism, is disposed on an engine body so as to minimize an amount of protrusion of the hydraulic-pressure control device from the engine body, while situating the hydraulic-pressure control device near the valve-pausing mechanism. A recess portion is formed on an external surface of a cylinder head or a head cover, and the hydraulic-pressure control device is disposed on the engine such that at least part of the hydraulic-pressure control device is accommodated in the recess portion.

Abstract: In a V-type engine for a vehicle, in which a hydraulic valve rest mechanism which selectively holds at least one of an intake valve and an exhaust valve corresponding to a part of plural cylinders in a valve-closed rest state in correspondence with a vehicle running status is provided in a valve actuation unit, and a hydraulic controller which controls hydraulic pressure of the valve rest mechanism is provided in a main engine body, to reduce the distance of oil passage from the hydraulic controller to the hydraulic valve rest mechanism and simplify the structure of the oil passage. A hydraulic controller is provided on at least one side surface of a cylinder head, and may be generally oriented along a line which is substantially parallel to a central axis of a cylinder bore.

Abstract: A V-type vehicle engine includes a main engine body with a front bank and a rear bank defining a V-type structure. A plurality of valve actuation units are respectively located in valve chambers in the front bank and the rear bank, to minimize the size of a cylinder head and a cylinder head cover in at least one of the front bank and the rear bank. A first valve actuation unit, with a double overhead camshaft structure having intake-side and exhaust-side camshafts individually corresponding to the intake valve and the exhaust valve, is located in a valve chamber in one of the front bank and the rear bank. A second valve actuation unit, having a common single camshaft for the intake valve and the exhaust valve, is located in a valve chamber in the other one of the front bank and the rear bank.

Abstract: A multicylinder engine for a motorcycle includes a valve actuation mechanism having a hydraulically-operated valve pausing mechanism for holding at least one of an intake valve and an exhaust valve of selected cylinders in a suspended state. The valve actuation mechanism operates the intake valve and the exhaust valve, and controls flow of oil through an oil passage which introduces working oil to the valve pausing mechanism from a hydraulic-pressure control device. Air-bleeding holes are formed in the cylinder head. The air-bleeding holes are fluidly connected with portions of the oil passages that are located at a highest level in the oil passages while the motorcycle is parked in an inclined state with its side stand down.

Abstract: A simpler configuration of a mechanism for stopping intake/exhaust valves opened/closed by a valve opening/closing mechanism of a rocker arm. An engine E includes an exhaust valve for opening/closing an exhaust port of an exhaust path with a first exhaust valve spring for energizing the exhaust valve in a valve closing direction. An exhaust valve drive cam is rotated in correspondence with the rotation of an engine crankshaft. A rocker arm is swingably provided between the exhaust valve and the exhaust valve drive cam with one end that abuts on the exhaust valve drive cam being pressed according to rotation of the exhaust valve drive cam and swinging to press the exhaust valve by a press member at the other end to move to the open side. An exhaust valve stopping mechanism is provided between the press member of the rocker arm and the exhaust valve.

Abstract: In a variable valve timing mechanism, a valve-lifting cam member is fitted, slidably in tile circumferential direction, onto a camshaft that is driven to rotate in synchronization with a crankshaft of a four-stroke cycle internal combustion engine. An eccentric collar is set between a driving collar fixed on the camshaft and the valve-lifting cam member. A driving projection is formed in the driving collar and engages with one of sandwiching portions of the eccentric collar. A driven protrusion is formed in the valve-lifting cam member and engages with another one of the sandwiching portions of the eccentric collar. A linkage mechanism includes the eccentric collar, the drive, and the driven protrusions. The variable valve timing mechanism adjusts the timing of opening and closing of the valve while the rotational phase of the valve-lifting cam member is cyclically varied relative to the camshaft by the eccentricity of the eccentric collar.