A control strategy includes: after an engine is energized, the continuously variable valve lift mechanism self learning to determine a current position; if the self learning is successful, the continuously variable valve lift mechanism being located at a maximum lift position, preparing for starting the engine, and determining a regulating mode based on a starting temperature, wherein at the time of normal temperature start, regulation is performed from the maximum lift position to a minimum lift position, and at the time of low temperature start, regulation is performed from the maximum lift position to a position where the two valves for the same cylinder have a maximum lift difference; if the self learning fails, entering a preliminary start mode; entering a CVVL control mode based on an operation condition of the engine; and powering off the engine.

A modular cylinder head is configured for use with combustion engine block configurations each having different valvetrain oiling pathways. Thus, when used with LA-style engine blocks, oil receiving/delivery ports provided by the cylinder head are compatibly interfaced with an oil outlet port provided by the engine block, thus allowing oil to pass from the engine block into the head for delivery to a valvetrain carried thereby. Alternatively, when the head is used with Magnum-style engine blocks, the oil receiving/delivery ports of the head are not used. Rather, a pushrod and lifter having internal ports are used by the cylinder head to allow oil to pass from the engine block, through the internal ports of the lifter and pushrod, and into the valvetrain.

Even in the case where, due to distortion (undulation) or the like of an end surface of an adjusting screw abutting on a valve stem end, there exists a non-linear undulation movement amount in a movement amount of the end surface with respect to a rotation return angle of the adjusting screw, the undulation movement amount is continuously measured, and a screw return movement amount based on a screw pitch and on the rotation return angle is continuously calculated, and, when a total movement amount of the undulation movement amount and the screw return movement amount has attained a prescribed clearance, return rotation is ended.

A valve spring for an engine valve of an internal combustion engine includes a body having a first end and an opposite second end and defining a plurality of coils having an outer surface, and a flocking material applied to at least a portion of the outer surface, the flocking material including a plurality of fibers configured to provide a passive vibro-acoustic damping to facilitate dynamic damping of the valve spring and reduce noise, vibration, and harshness.

An oil passage switching valve suitable for a valve timing changing apparatus includes: a valve body, opening or closing an oil passage of operating oil; an urging spring, urging to position the valve body to a position corresponding to the retard position in a pause state; and a switching element, positioning the valve body to a position corresponding to the retard position when a state quantity of the operating oil is in a first range, and switching a position of the valve body in response to the state quantity (pressure or temperature) of the operating oil while resisting an urging force of the urging spring to position the valve body to a position corresponding to the advance position when the state quantity of the operating oil is in a second range greater than the first range.

A control strategy includes: after an engine is energized, the continuously variable valve lift mechanism self learning to determine a current position; if the self learning is successful, the continuously variable valve lift mechanism being located at a maximum lift position, preparing for starting the engine, and determining a regulating mode based on a starting temperature, wherein at the time of normal temperature start, regulation is performed from the maximum lift position to a minimum lift position, and at the time of low temperature start, regulation is performed from the maximum lift position to a position where the two valves for the same cylinder have a maximum lift difference; if the self learning fails, entering a preliminary start mode; entering a CVVL control mode based on an operation condition of the engine; and powering off the engine.

An engine is provided with: a crank case that has a first crank shaft insertion hole and a second crank shaft insertion hole along the vertical direction; a crank shaft that is inserted into the first and second shaft insertion holes; and a cylinder unit that extends in the front-rear direction from the crank case. The cylinder unit is provided with a cylinder base that is positioned inside the crank case, and a cylinder block that is positioned outside the crank case. The cylinder unit is detachably attached to the crank case.

A rocker arm assembly having a rocker arm including a pair of sidewalls, each sidewall defining a support aperture, a rocker arm support including a pair of opposed bearing support arms, each bearing support arm being disposed within a corresponding support aperture of the rocker arm and defining a lubrication groove extending along an outer surface thereof, and a pair of radial roller bearings, each including an inner cup, an outer cup, and a plurality of rollers disposed therebetween, wherein each radial roller bearing is disposed both on a corresponding bearing support arm and within a corresponding support aperture.

In order to ensure a simple, reliable and recuperative operation in a hydraulic drive (10) for accelerating and braking a gas exchange valve (20) of internal combustion engines or other reciprocating engines, it is proposed that a first pressure reservoir (41) for providing a first pressure p.sub.1 comprises a restoring energy accumulator, preferably configured as a spring (25), and at least one hydraulic base pressure reservoir (40), which has a lower pressure p.sub.0 than the first pressure reservoir (41). In a connecting line (48) between the first hydraulic pressure reservoir (41) and the working cylinder (22), a controllable opening (49) of a first valve (46) comprising at least one check valve (47) is arranged upstream or downstream in the flow path, which allows the pressure medium (30) to flow in the direction of working cylinder (22), but prevents a backflow towards the pressure reservoir (41).

In order to also initiate the closing movement or to enable the breaking of the gas exchange valve in a hydraulically simple and reliable manner, in a second connecting line (58) between the first pressure reservoir (41) and the working cylinder (22) there is arranged a controllable opening (59) of a second valve (56) comprising a check valve (57), which prevents a flow in the direction of the working cylinder (22), but allows a return flow in the direction of the pressure reservoir (41).

A variable valve mechanism includes a first member and a second member which are disposed between a cam and a valve, a switch pin that is displaced to connect and disconnect the first member to and from the second member, and a displacement device. The displacement device includes a ring-shaped plate that is fitted on a camshaft of the cam so as to be co-rotatable with the camshaft and slidable in a longitudinal direction of the camshaft and that has one side surface configured to contact the switch pin and has the other side surface including a tapered surface formed so that a plate thickness increases toward a rotational direction, and a support device formed by a support pin and a moving device that moves the support pin to a position where the support pin contacts the tapered surface and a position not contacting the tapered surface.