Variable valve event engine

A variable valve event engine comprising:

• a rocker shaft disposed along said engine;
• a camshaft disposed parallel to said rocker shaft and synchronized with a crankshaft of said engine;
• a plurality of cams having cam profiles different from each other fixed on said camshaft so as to be adjacent to each other;
• a rocker arm for actuating a valve of said engine, said rocker arm being pivotably and slidably disposed on said rocker shaft;
• a rocker arm slide shaft disposed parallel and longitudinally movable with respect to said rocker shaft;
• a hydraulic piston-cylinder having two cylinder chambers for longitudinally moving said rocker arm slide shaft;
• a two-directional control valve for actuating said hydraulic piston-cylinder in accordance with changes in the operating conditions of the engine, said control valve being in fluid communication with said two cylinder chambers, with a hydraulic pump via a supply pipe, and with a reservoir via a return pipe, said supply pipe including a relief pipe and relief valve branching from said supply pipe between said pump and said control valve;
• a spring connecting said rocker arm slide shaft with the rocker arm for transmitting the movement of said rocker arm slide shaft to said rocker arm to move said rocker arm between longitudinally spaced, predetermined positions, each being aligned with one of said cams;
• a first detector for sensing the temperature of the lubricant utilized in said hydraulic piston-cylinder;
• a second detector for sensing the load of said engine;
• and
• a control, connecting said control valve and said first and second detectors, for switching said control valve in accordance with the load of said engine detected by said second detector only when said first detector detects that said temperature of said lubricant is higher than a predetermined temperature.

A variable valve event engine comprising:

• a rocker shaft disposed along said engine;
• a camshaft disposed parallel to said rocker shaft and synchronized with a crankshaft of said engine;
• a plurality of cams having cam profiles different from each other fixed on said camshaft so as to be adjacent to each other;
• a rocker arm for actuating a valve of said engine, said rocker arm being pivotably and slidably disposed on said rocker shaft;
• a rocker arm slide shaft disposed parallel and longitudinally movable with respect to said rocker shaft;
• a hydraulic piston-cylinder having two cylinder chambers for longitudinally moving said rocker arm slide shaft;
• a two-directional control valve for actuating said hydraulic piston-cylinder in accordance with changes in the operating conditions of the engine, said control valve being in fluid communication with said two cylinder chambers, with a hydraulic pump via a supply pipe, and with a reservoir via a return pipe, said supply pipe including a relief pipe and relief valve branching from said supply pipe between said pump and said control valve;
• a spring connecting said rocker arm slide shaft with said rocker arm for transmitting movement of said rocker arm slide shaft to said rocker arm to move said rocker arm between logitudinally spaced, predetermined positions each being aligned with one of said cams;
• a detector for sensing the temperature of the lubricant utilized in said hydraulic piston-cylinder;
• and
• control means connected to said control valve and said detector for switching said control valve only when said detector detects that said temperature of said lubricant is higher than a predetermined temperature so that said valve is selectively actuated by means of one of said cams.

A variable valve event engine comprising:

• a rocker shaft disposed along said engine;
• a camshaft disposed parallel to said rocker shaft and synchronized with a crankshaft of said engine;
• a plurality of cams having cam profiles different from each other fixed on said camshaft so as to be adjacent to each other;
• a rocker arm for actuating a valve of said engine, said rocker arm being pivotably and slidably disposed on said rocker shaft;
• a rocker arm slide shaft disposed parallel and longitudinally movable with respect to said rocker shaft;
• a hydraulic piston-cylinder having two cylinder chambers for longitudinally moving said rocker arm slide shaft;
• a two-directional control valve for actuating said hydraulic piston-cylinder in accordance with changes in the operating conditions of the engine, said control valve being in fluid communication with said two cylinder chambers, with a hydraulic pump via a supply pipe, and with a reservoir via a return pipe, said supply pipe including a relief pipe and relief valve branching from said supply pipe between said pump and said control valve;
• a spring connecting said rocker arm slide shaft with the rocker arm for transmitting the movement of said rocker arm slide shaft to said rocker arm to move said rocker arm between longitudinally spaced, predetermined positions, each being aligned with one of said cams;
• a first detector for sensing the temperature of the lubricant utilized in said hydraulic piston-cylinder;
• a second detector for sensing the rotational speed of the engine;
• and
• a control, connecting said control valve and said first and second detectors, for switching said control valve in accordance with the rotational speed of said engine detected by said second detector only when said first detector detects that said temperature of the lubricant is higher than a predetermined temperature.