초록 ▼

A valve operation changing system of an internal combustion engine, comprises a rocker arm (3, 3′) to operate an intake or exhaust valve (2, 11), and a control device (19A, 19B, 22, 23, 24, 25, 26) for axially moving the rocker arm so as to selectively cause the rocker arm (3, 3′) to engage with fir

A valve operation changing system of an internal combustion engine, comprises a rocker arm (3, 3′) to operate an intake or exhaust valve (2, 11), and a control device (19A, 19B, 22, 23, 24, 25, 26) for axially moving the rocker arm so as to selectively cause the rocker arm (3, 3′) to engage with first or second cam (12, 13; 45A, 45B) in accordance with an engine operating condition. The control device includes an actuator having first and second hydraulic pressure chambers (19A, 19B; 50a, 50b) whose pressures move the rocker arm (3, 3′) to engage with the first and second cams (12, 13; 45A, 45B), respectively. A flow direction changing valve (23) is provided to selectively supply the first or second hydraulic pressure chambers (19A, 19B; 50a, 50b) with oil from an oil pressure source (21), in accordance with the engine operating condition. A stopper device (26) is provided to restrict the movement of the rocker arm (3, 3′). Additionally, a timing lifter (25) is provided to release the rocker arm (3, 3′) from the restriction by the stopper device in timed relation to the rotation of the first and second cams (12, 13; 45A, 45B), thereby accomplishing the axial movement of the rocker arm (3, 3′) at a predetermined suitable timing and at a higher speed.

대표청구항 ▼

A valve operation changing system of an internal combustion engine, comprising: first and second cams (12, 13; 45A, 45B) formed on a camshaft (6) and different in cam profile from each other; a rocker arm (3, 3′) mounted on a rocker shaft and swingable around the rocker shaft to operate an engine va

A valve operation changing system of an internal combustion engine, comprising: first and second cams (12, 13; 45A, 45B) formed on a camshaft (6) and different in cam profile from each other; a rocker arm (3, 3′) mounted on a rocker shaft and swingable around the rocker shaft to operate an engine valve (2, 11) upon engagement with said cams, said rocker arm (3, 3′) being axially movable to engage with said first cam (12, 45A) when said rocker arm is put in a first position while with said second cam (13, 45B) when said rocker arm is put in a second position; and means (21, 22, 23, 19A, 19B, 24, 25, 26) for selectively putting said rocker arm in one of said first and second positions in accordance with an engine operating condition, said putting means including an oil pressure source (21) for supplying pressurized hydraulic oil, a flow direction changing valve (23) fluidly connected to said oil pressure source and arranged to selectively take one of its first and second states, means defining first and second hydraulic pressure chambers (19A, 19B; 50a, 51a) which are fluidly connectable with said oil pressure source through said flow direction changing valve, said first hydraulic pressure chamber (19A; 50a) being suppliable with the oil fed through said flow direction changing valve so as to put said rocker arm into the first position when said flow direction changing valve is in the first state, said second hydraulic pressure chamber (19B; 51a) being suppliable with the oil fed through said flow direction changing valve so as to put said rocker arm into the second position when said flow direction changing valve is in the second state, stopper means (26) controlling position of said flow direction changing valve to restrict the axial movement of said rocker arm; and means (25) for releasing said flow direction changing valve from position control of said stopper means in timed relation to the rotation of said first and second cams when actuated, whereby the movement of said rocker arm between the first and second positions takes place in timed relation to the rotation of said first and second cams.