Compressed gas engine with pistons and cylinders

An engine driven by compressed gas, comprising:

• an engine having a plurality of reciprocating pistons within cylinders, said pistons rotating a crankshaft;
• each cylinder closed at an upper end by a head plate to form a compression chamber within each cylinder between each piston upper end and the head plate;
• a plurality of intake passageways, each extending from one compression chamber through the head plate;
• a plurality of intake valves, one in each intake passageway, each operable between open and closed positions to open and close each intake passageway;
• a plurality of exhaust passageways, each extending from one compression chamber through the associated cylinder wall;
• a plurality of exhaust valves, one in each exhaust passageway, each operable between open and closed positions to open and close each exhaust passageway;
• a plurality of lift rods, each extending between one of said intake and exhaust valves and said crankshaft, for moving the valves to their open positions;
• a plurality of cams on said crankshaft arranged to selectively open the intake and exhaust valves in a predetermined sequence;
• a source of compressed gas connected via a pneumatic line to each of said intake passageways;
• and
• operable gas flow regulator interposed between the gas source and the intake passageways for selectively controlling the amount of gas provided to flow to the engine;
• said valves arranged and shaped to be biased to a closed position by gas within the intake and exhaust passageways, respectively.