Device for varying a valve timing and lift for an internal combustion engine

a device for varying valve timing and lift for an internal combustion engine which has a poppet valve and a cam, comprising:

• a first valve lifter adapted to contact said poppet valve;
• a second valve lifter, provided between said first valve lifter and said cam, said first valve lifter and said second valve lifter defining an oil pressure chamber therebetween which has an inlet portion and an outlet portion;
• oil supply path means, coupled to said inlet portion for supplying a pressurized fluid comprising oil into said oil pressure chamber, said pressurized fluid being the only force applied to said chamber;
• oil extract path means, coupled to said outlet portion, for extracting said fluid from said oil pressure chamber;
• and
• high-speed response control valve means, provided in said oil extract path means, for continuously allowing said fluid to escape from said pressure chamber during a specified period after start of cam lift operation to vary the volume of said oil pressure chamber and for controlling the valve timing and lift corresponding to engine operating conditions, said valve means including a check ball valve disposed so that pressure of said fluid closes said oil extract path means and actuator means for directly opening said check valve against said fluid pressure.

A method of controlling a valve, comprising the steps of:

• transferring motion from a cam to a first valve lifter;
• transferring motion from a second valve lifter to said valve;
• controlling the volume of a pressure chamber defined between said first and second valve lifters which has independent inlet and outlet paths, by supplying a pressurized oil into said pressure chamber, through said inlet path and selectively commanding a check ball valve in said outlet path to open against said oil pressure, said check ball valve disposed so that said oil pressure would normally close said check ball valve;
• selectively opening said check ball valve by transmitting force from an actuator to said check ball valve;
• using only said oil pressure as controlled by said check ball valve to apply a force to said second valve lifter.