Combustion powered driver

A combustion powered driver comprising:

• a driver body defining a combustion chamber;
• a fuel injection valve configured to selectively control a flow of fuel into the combustion chamber;
• an ignition module configured to ignite fuel within the combustion chamber;
• a ram movable within the driver body;
• a piston movable within the driver body, wherein the piston defines a passageway therethrough;
• a piston valve disposed at least partially within the piston and configured to selectively open and close the passageway;
• a biasing member configured to urge the piston apart from the ram;
• wherein the piston overcomes the urging of the biasing member to impact the ram responsive to combustion within the combustion chamber;
• wherein the piston is configured to reciprocate between a downward stroke in which the piston impacts the ram responsive to combustion in the combustion chamber and a return stroke in which the piston moves away from the ram due to the urging of the biasing member;
• wherein a ram projection extending from the ram moves the piston valve to an open position when the piston impacts the ram so the piston valve is in an open position in the return stroke;
• and
• wherein a protrusion extending into the combustion chamber moves the piston valve to a closed position when the piston moves away from the ram so the piston valve is in a closed position in the downward stroke.

A free piston internal combustion engine comprising:

• a cylinder having a first end with a first projection and a second end with a second projection;
• a combustion chamber disposed within the cylinder;
• an ignition module configured to ignite fuel within the combustion chamber;
• a piston movable within the cylinder between the first end and the second end, wherein the piston moves toward the second end responsive to combustion in the combustion chamber, wherein the piston defines a passageway therethrough;
• a biasing member configured to urge the piston toward the first end of the cylinder;
• a piston valve movable between an open position and a closed position, wherein the piston valve prevents fluid flow through the passageway in the closed position, but allows fluid flow through the passageway in the open position, wherein at least a portion of the piston valve is disposed within the piston;
• wherein the piston is configured to reciprocate between a downward stroke in which the piston impacts the second end of the cylinder responsive to combustion in the combustion chamber and a return stroke in which the piston impacts the first end of the cylinder due to the urging of the biasing member;
• wherein the first projection is received in registry with the passageway to move the piston valve to a closed position when the piston impacts the first end of the cylinder so the piston valve is in a closed position in the downward stroke;
• and
• wherein the second projection is received in registry with the passageway to move the piston valve to an open position when the piston impacts the second end of the cylinder so the piston valve is in an open position in the return stroke.