Internal combustion engine with automatic compression release

An internal combustion engine comprising:

• a cylinder having an exhaust port;
• a piston movable within said cylinder in a compression stroke;
• an exhaust valve for opening and closing said exhaust port;
• a cam shaft including a cam member for selectively moving said exhaust valve between open and closed positions;
• an auxiliary cam movable between an operative position, where said exhaust valve is held open during the compression stroke, and an inoperative position;
• a biasing member biasing said auxiliary cam toward said inoperative position:
• a collar member positioned at least partially around said cam shaft, said spring being positioned between said collar member and a portion of said auxiliary cam;
• and
• an auxiliary shaft rotatably mounted within said cam shaft and adapted to move said auxiliary cam between the operative position and the inoperative position.

An internal combustion engine comprising:

• a cylinder having an exhaust port;
• a piston movable within said cylinder in a compression strike;
• an exhaust valve for opening and closing said exhaust port;
• a cam shaft having a central axis and including a cam member for selectively moving said exhaust valve between open and closed positions, said cam shaft including a radially-extending opening positioned at least partially through said cam shaft;
• an auxiliary cam slidably positioned within said opening and movable along an axis radial to the camshaft between an operative position, where the exhaust valve is held open during the compression stroke, and an inoperative position, said auxiliary cam including an outer end surface adapted to extend out of said opening, said end surface comprising a substantially straight portion that is angled with respect to said central axis.