초록 ▼

A hydraulic tappet is used in a variable valve lift engine. The tappet comprises an outer case having a pressure chamber formed therein, an inner case having an oil chamber formed therein and engaged within the outer case, and a check valve disposed between the pressure chamber and the oil chamber.

A hydraulic tappet is used in a variable valve lift engine. The tappet comprises an outer case having a pressure chamber formed therein, an inner case having an oil chamber formed therein and engaged within the outer case, and a check valve disposed between the pressure chamber and the oil chamber. The pressure chamber is communicated with an electromagnetic valve via an additional check valve. The electromagnetic valve is actuated in accordance with changes in operating conditions of an engine, i.e. the engine load and the temperature of the engine, so that the oil pressure between the additional check valve and the electromagnetic valve is maintained at a predetermined level. As a result, the valve lift of the engine can be varied at an optimum level in accordance witi changes in the operating conditions of the engine.

대표청구항 ▼

A variable valve lift mechanism for cooperating with a crankshaft-synchronized cam and a rocker arm to actuate a valve in an internal combustion engine, said mechanism comprising: an outer case having a pressure chamber formed therein, one end of said outer case abutting said cam; an inner case havi

A variable valve lift mechanism for cooperating with a crankshaft-synchronized cam and a rocker arm to actuate a valve in an internal combustion engine, said mechanism comprising: an outer case having a pressure chamber formed therein, one end of said outer case abutting said cam; an inner case having an oil chamber formed therein and being slidably and sealingly disposed in said outer case, one end of said inner case abutting one end of said rocker arm; a first check valve disposed between said pressure chamber and said oil chamber for controlling one-way fluid communication from said oil chamber to said pressure chamber; an electromagnetic valve actuated in response to changes in operating conditions of said engine, said electromagnetic valve being in fluid communication with said pressure chamber; a second check valve disposed between said pressure chamber and said electromagnetic valve for controlling one-way fluid communication from said pressure chamber to said electromagnetic valve; and a pressure sensor disposed between said second check valve and said electromagnetic valve for sensing the fluid pressure therein and for permitting actuation of said electromagnetic valve to maintain said sensed fluid pressure at a predetermined level.