Abstract: A valve driving apparatus includes a cam, a force transfer member transferring force of the cam to a valve, and a shim interposed between the cam and the force transfer member and movable on the force transfer member. The shim has a first portion, a part of which first portion is always in contact with the force transfer member while the shim is being moved on the force transfer member in accordance with a motion of the cam.

Abstract: A valve drive apparatus having a shim which is prevented from interfering with a cylinder head without decreasing abrasion resistance between the shim and a lifter contacting the shim. A three-dimensional cam includes a cam portion having a slanting cam surface inclined with respect to a rotational axis of the cam. The cam is movable along the rotational axis. The lifter transmits a force generated by a camming action of the cam to the valve. The lifter has a first surface contacting the valve and a second surface substantially opposite to the first surface. A shim is interposed between the cam and the lifter. The shim has a first surface contacting the cam and a second surface opposite to the first surface. The second surface of the shim has a convex spherical shape, and the second surface of the lifter has a concave spherical shape so as to receive the second surface of the shim.

Abstract: A variable compression ratio control device includes a mechanism for varying a compression ratio of an engine in response to engine driving conditions, at least between a higher stage and a lower stage, a compression ratio detecting sensor for detecting a current compression ratio, a sensor fault detecting unit for detecting a malfunction of the compression ratio detecting sensor, and a fail-safe unit for lowering and fixing the compression ratio when the sensor fault detecting unit detects a malfunction of the compression ratio detecting sensor.

Abstract: A device for locking rotation of an eccentric bearing used in a compression ratio changing device for an internal combustion engine where rotation of the eccentric bearing interposed between a connecting rod and a piston-pin changes the compression ratio. The device includes at least two groups of lock-pins, lock-pin holes formed in the connecting rod and lock holes formed in the eccentric bearing. The eccentric bearing is always locked in rotation relative to the connecting rod except when the compression ratio is exchanged. The locking of the rotation of the eccentric bearing suppresses slap noises of the piston and abrasion of the sliding surfaces of the device and improves durability of the compression ratio changing device.

Abstract: A compression ratio changing device for an internal combustion engine using an eccentric bearing interposed between a piston-pin and a connecting rod. A lock hole is formed in the eccentric bearing and a lock-pin hole is formed in the connecting rod. A lock-pin is slidably inserted in the lock-pin hole and can move into or out of the lock hole. When the lock-pin engages lock hole, the rotation of the eccentric bearing is locked. When the lock-pin moves apart from the lock hole, the rotation of the eccentric bearing becomes free. To obtain a smooth entry of the lock-pin into the lock hole, a guide groove is formed in the outer portion of the eccentric bearing. A portion of the surface of the lock hole forms a colliding surface for colliding with the lock-pin. A deformation absorbing groove is formed at the outer portion of the colliding surface.

Abstract: A device for locking/unlocking rotation of an eccentric bearing interposed between a piston-pin and a connecting rod of an internal combustion engine for changing the compression ratio of the engine. The eccentric bearing has two lock holes, two guide grooves extending circumferentially from the lock holes and two colliding surfaces. The connecting rod has at least one lock-pin hole and a lock-pin is slidably inserted in the lock-pin hole. When the lock-pin is driven toward the eccentric bearing, the lock-pin can move toward the eccentric bearing and can engage the lock hole, thereby locking the rotation of the eccentric bearing. Since the colliding surfaces are provided opposed to said guide grooves, the lock-pin can reliably engage one of the lock holes without jumping the lock hole whether the eccentric bearing rotates in a normal direction or in a reverse direction. As a result, a reliable changing between a high compression ratio and a low compression ratio can be obtained.