Abstract: A first variable valve actuating mechanism varies an operating angular range of an intake valve, a second variable valve actuating mechanism varies a center angle of the operating angular range, and a control unit controls, through the first and second variable valve actuating mechanisms, the operating angular range and the center angle in accordance with an operation condition of the engine. The control unit is configured to carry out, in a low-output operation range of the engine, advancing the center angle with increase of the engine output while making the variation of the center angle larger than that of the operating angular range; and in a middle-output operation range of the engine, increasing the operating angular range with increase of the engine output while making the variation of the operating angular range larger than that of the center angle.

Abstract: In a VVA apparatus for an internal combustion engine wherein the position of contact of a cam face of a VO cam with respect to the top face of a valve lifter is changed in accordance with a change in a rocking fulcrum of a rocker arm to alter the valve lift, the maximum valve lift is obtained in a first rotated position of a control shaft where an axis of a control cam is adjacent to a driving shaft. The minimum valve lift is obtained in a second rotated position of the control shaft where the axis of the control cam is positioned near a first pivotal point of the rocker arm and a crank arm with respect to a first line connecting the axis of the control shaft and the axis of the control cam upon the maximum valve lift.

Abstract: A variable valve actuation (VVA) apparatus comprises an eccentric rotary (ER) cam fixed to a driving shaft for rotation therewith, a pivotal valve operating (VO) cam, a rocker arm having a first arm and a second arm, a control rod having an eccentric control cam, and a crank arm. The eccentric control cam supports the rocker arm for pivotal motion. The crank arm interconnects the ER cam and the first arm of the rocker arm. A link interconnects the second arm of the rocker arm and the VO cam.

Abstract: A valve-operating device for an internal combustion engine equipped with two cylinder banks each having a variable valve timing and working angle mechanism comprises a drive shaft, a cylindrical hollow camshaft fitted to an outer periphery of the drive shaft to be rotatable relatively about the drive shaft, a non-uniform velocity coupling including an annular disc disposed between the drive shaft and the camshaft for transmitting motion of rotation from the drive shaft to the camshaft, permitting a phase change of the camshaft relative to the drive shaft with non-uniform rotation during eccentric motion of the annular disc, and a control housing rotatably supporting the annular disc. Also provided is a decentering mechanism supporting the control housing rockably to produce the eccentric motion of the annular disc.

Abstract: A rocker arm is provided free to pivot on a rocker shaft fixed to an engine. A valve that opens and closes according to the oscillation of this rocker arm, and a cam that causes this rocker arm to oscillate in synchronism with the engine, are also provided. A thrust fin projecting in a radial direction is formed in a one-piece construction with the rocker and is narrower than the rocker arm. A guide groove engaging with the thrust fin is formed on the engine so as to prevent the rocker arm from displacing in the axial direction of the rocker shaft. As the width of the guide groove is small, it can be formed easily and with high precision by cutting a part of the engine with an end mill.