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 motorcycle engine includes a crankcase housing a crankshaft, and a transmission unit therein, a cylinder block disposed above the crankcase, a cylinder head disposed above the cylinder block, and an intake system arranged behind the cylinder head, and a knock sensor arranged on an upper surface of the crankcase. The knock sensor is arranged behind the cylinder head, and disposed between the intake system and the cylinder block, such that the knock sensor does not restrict arrangement of additional functional parts of the engine on an upper surface of the crankcase. The knock sensor is substantially surrounded and protected by the intake system, the cylinder head, the cylinder block and the crankcase.

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: 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 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: A cylinder head cover, on which a breather chamber wall and control valve device are mounted is not enlarged while the capacity of a breather chamber is increased. For an internal combustion engine, control valve devices, which control the operation of a hydraulic valve stop mechanism that serves as a cylinder stop mechanism, and an outer chamber wall of a breather chamber wall that forms a breather chamber into which a blow-by gas flows, project in a predetermined direction and are mounted on the outer surface of a top wall of a cylinder head cover. When viewed in the predetermined direction, the outer chamber wall has an overlap section that overlaps with a part of the control valve device. Therefore, the overlap section is covered in the particular direction by the control valve device.

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: Provided is a power unit for a vehicle including an engine main body of an engine having: a valve system capable of changing operational modes of each engine valve; valve controlling apparatuses for controlling operations of the valve system; and a crankcase housing a transmission, the engine main body being mounted on a vehicle frame. The power unit for a vehicle achieves reduction in size of the engine main body in a direction along the axis of a cylinder, and increases the freedom of arranging parts designed to be placed on an upper end portion of the engine main body. The valve controlling apparatuses are attached to the top surface of the crankcase.

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: A power system for a vehicle includes a hydraulic pressure generating device, a first hydraulically operated device, a second hydraulically operated device, a common oil channel, a first bifurcated oil channel, a second bifurcated oil channel, and an oil state detector. The first hydraulically operated device is configured to be operated by liquid supplied from the hydraulic pressure generating device. The second hydraulically operated device is configured to be operated by liquid supplied from the hydraulic pressure generating device. The common oil channel is connected to the hydraulic pressure generating device. The first bifurcated oil channel connects the common oil channel and the first hydraulically operated device. The second bifurcated oil channel connects the common oil channel and the second hydraulically operated device. The oil state detector is provided in the common oil channel and configured to detect the state of the liquid.

Abstract: A power unit for a small type vehicle wherein a speed change mechanism is disposed on a lateral side of a crankcase on the side of one end of a crankshaft. A valve operation controller for controlling the operations of valve operation mode change mechanisms and a speed change controller for controlling a speed change operation of a speed change mechanism are attached to an engine body, to lay out the valve operation controller and the speed change controller in good balance of center of gravity so as to prevent the center of gravity of the power unit from being deviated to one side. The valve operation controller and the speed change controller being attached to the engine body on the opposite side of the clutch device with respect to a vehicle body center line in a direction along the axis of the crankshaft.

Abstract: There is provided an engine for a small vehicle where driven sprockets, around which a cam chain for transmitting power from a crankshaft is wound, are provided at one end of camshafts that form a part of a valve system provided with hydraulic valve-operation mode changing mechanisms; and a valve-moving hydraulic pressure control device, which controls hydraulic pressure applied to the valve-operation mode changing mechanisms, is provided in the engine body. In the engine, it is possible to increase the degree of freedom in disposing the oil passage between the valve-operation mode changing mechanism and the valve-moving hydraulic pressure control device while avoiding the increase in the number of parts and assembly man-hours. A valve-moving hydraulic pressure control device is mounted on the side surface of the engine body on the side opposite to a cam chain in an axial direction of a camshaft.

Abstract: There is provided a saddle-riding type small vehicle where a power unit is mounted on a vehicle body frame. The power unit includes a valve control device that controls the operation of valve-operation mode changing mechanisms capable of changing operation modes of engine valves, and a clutch control device that controls the operation of a clutch unit provided between a crankshaft and a shift mechanism so as to shift the connection/disconnection of power transmission. In the vehicle, the valve control device and the clutch control device are disposed to balance the center of gravity, so as to make a power unit compact. A valve control device and a clutch control device are disposed on left and right sides of a center line CB of a vehicle in a width direction of the vehicle.

Abstract: A cylinder head cover, on which a breather chamber wall and control valve device are mounted is not enlarged while the capacity of a breather chamber is increased. For an internal combustion engine, control valve devices, which control the operation of a hydraulic valve stop mechanism that serves as a cylinder stop mechanism, and an outer chamber wall of a breather chamber wall that forms a breather chamber into which a blow-by gas flows, project in a predetermined direction and are mounted on the outer surface of a top wall of a cylinder head cover. When viewed in the predetermined direction, the outer chamber wall has an overlap section that overlaps with a part of the control valve device. Therefore, the overlap section is covered in the particular direction by the control valve device.

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 V-type engine for a vehicle is provided with front and rear banks including intake and exhaust valves exposed to a combustion chamber, a valve operating device for operating the engine valves, a valve stop mechanism for stopping the operation of the engine valves according to an operational condition of the vehicle, and an actuator for driving a throttle valve. A valve stop mechanism is provided in either the front bank or the rear bank. An actuator provided in one of the front bank and the rear bank excluding the valve stop mechanism is lower in height than the actuator provided in the other of the front bank.

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: A motorcycle engine includes a crankcase housing a crankshaft, and a transmission unit therein, a cylinder block disposed above the crankcase, a cylinder head disposed above the cylinder block, and an intake system arranged behind the cylinder head, and a knock sensor arranged on an upper surface of the crankcase. The knock sensor is arranged behind the cylinder head, and disposed between the intake system and the cylinder block, such that the knock sensor does not restrict arrangement of additional functional parts of the engine on an upper surface of the crankcase. The knock sensor is substantially surrounded and protected by the intake system, the cylinder head, the cylinder block and the crankcase.

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 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.