Free piston internal combustion engine
AssigneeSunPower Corporation
InventorWilliam T. Beale
Life of this patent
Estimating the term…
Abstract
A free piston internal combustion engine having improved valve timing. A pair of oppositely disposed combustion chamber passageways extending between the combustion chamber and the earth's atmosphere, each have a combustion chamber valve for controlling the passage of gas through the passageways. The combustion chamber valves are essentially simultaneously opened and closed to permit independent variation and control of the compression ratio, expansion ratio, and stroke of the engine. When the valves are opened, the combustion chamber is purged or supercharged with combustion supporting air, and closed to initiate compression. Variable control of the piston positions at which the valves are opened and closed permits the engine to operate at a high efficiency over a broad range of power output loading conditions.
Claims26
In a free piston internal combustion engine including at least one piston slidingly reciprocatable in a cylinder and having an end face bounding and defining a combustion chamber portion of the cylinder, the engine also including a driver linked to the piston for driving the piston through its compression stroke and a fuel injector in communication with the combustion chamber, the improvement comprising:
- (a) a combustion chamber valve in a passageway extending between the combustion chamber and the earth's atmosphere for controlling passage of gas between the combustion chamber and the earth's atmosphere;
- (b) a valve closing actuator linked to the combustion chamber valve;
- (c) a first, piston-position sensor linked to the valve closing actuator and initiating closure of the valve in response to a selected first position of the piston in the cylinder;
- and
- (d) a piston-position responsive valve opening actuator wherein the valve opening and closing events may vary relative to piston position to affect power output linked to the combustion chamber valve.
A method for operating a free piston internal combustion engine including at least one piston having an end face bounding and defining a combustion chamber portion of the cylinder, the piston being slidingly reciprocatable between maximum and minimum combustion chamber volumes, the engine also including a driver linked to the piston for driving the piston through its compression stroke and having a fuel injector in communication with the combustion chamber, the method comprising:
- (a) venting the combustion chamber at a piston position near the end of an expansion stroke to terminate an expansion of combustion gas and initiate exhaust of combustion products;
- (b) terminating the venting at a piston position to terminate the exhaust and initiate compression;
- and
- (c) varying at least one of said valve opening and valve closing events relative to piston positions in response to variations in desired output power.
Dependencies are inferred from the claim text.