Abstract: A variable valve drive mechanism of an internal combustion engine is provided which includes a camshaft that is operatively connected to a crankshaft of the engine such that the camshaft is rotated by the crankshaft, a rotating cam provided on the camshaft, and an intermediate drive mechanism disposed between the camshaft and an intake or exhaust valve of the engine. The intermediate drive mechanism is supported rockably on a shaft that is different from the camshaft, and includes an input portion operable to be driven by the rotating cam of the camshaft, and an output portion operable to drive the valve when the input portion is driven by the rotating cam. The variable valve drive mechanism further includes an intermediate phase-difference varying device for varying a relative phase difference between the input portion and the output portion of the intermediate drive mechanism.

Abstract: A variable valve drive mechanism of an internal combustion engine is provided which includes a camshaft that is operatively connected to a crankshaft of the engine such that the camshaft is rotated by the crankshaft, a rotating cam provided on the camshaft, and an intermediate drive mechanism disposed between the camshaft and an intake or exhaust valve of the engine. The intermediate drive mechanism is supported rockably on a shaft that is different from the camshaft, and includes an input portion operable to be driven by the rotating cam of the camshaft, and an output portion operable to drive the valve when the input portion is driven by the rotating cam. The variable valve drive mechanism further includes an intermediate phase-difference varying device for varying a relative phase difference between the input portion and the output portion of the intermediate drive mechanism.

Abstract: An engine has a crankshaft, a combustion chamber and a valve that selectively opens and closes the combustion chamber. The valve has a timing relationship to the crankshaft and lift characteristic. A control device hydraulically alters at least one of the timing relationship and the lift characteristic. A lubricant passage is connected with the control device to supply oil to a mechanism that is formed by engine parts slidably contacting one another within the engine. An auxiliary passage is provided for supplying the oil to the mechanism. Oil supplied from an oil pump to said auxiliary passage is restricted by an electromagnetic valve that is actuated based on the instruction from an electric controller when engine speed is lower than a predetermined value.

Abstract: An engine has a crankshaft, a combustion chamber and a valve. The valve opens and closes the combustion chamber. The valve has a lift characteristic that is altered by a control device according to a change of hydraulic pressure therein. The engine has a lubricant passage that is connected with an oil pump and supplies oil to a mechanism formed by parts slidably connecting one another within the engine. A hydraulic pressure passage extends into an interior of the control device to exchange the hydraulic pressure with the control device, thereby the control device is actuated to alter the lift characteristic. The oil pump supplies the oil to the pressure passage when connected with the pressure passage. The oil pan supplies the oil to the pressure passage when connected with the pressure passage. A switching valve selects one of the oil pump and the oil pan to connect the selected one with the control device based on the engine speed.