Digital hydraulic opposed free piston engines and methods
AssigneeSturman Digital Systems, LLC
InventorOded Eddie Sturman
Life of this patent
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Abstract
Digital hydraulic opposed free piston internal combustion engines having a pair of free pistons in a pair of cylinders defining a combustion chamber above each free piston. The pair of free pistons is arranged to move within the pair of cylinders with parallel axes of free piston motion, and preferably co-linear axes of free piston motion. At least one hydraulic plunger is under each free piston with each hydraulic plunger in a respective hydraulic cylinder. The hydraulic cylinders are coupled to electronically controlled hydraulic cylinder valving. A controller controls the electronically controlled hydraulic cylinder valving to control the pair of free pistons to have substantially equal and opposite motions.
Claims22
An internal combustion engine comprising:
- a pair of free pistons in a pair of cylinders defining a combustion chamber above each free piston, the pair of free pistons arranged to move within the pair of cylinders with parallel axes of free piston motion and not being physically connected to each other and each not being physically connected to any other free piston to allow the two free pistons to move in opposite directions at the same time;
- at least one hydraulic plunger under each free piston, each hydraulic plunger in a respective hydraulic cylinder, the hydraulic cylinders being coupled to electronically controlled hydraulic cylinder valving;
- and
- a controller, the controller controlling the electronically controlled hydraulic cylinder valving to control the pair of free pistons to have substantially equal and opposite motions at the same time.
An internal combustion engine comprising:
- a pair of free pistons in a pair of cylinders defining a combustion chamber above each free piston, the pair of free pistons arranged to move within the pair of cylinders along the same axis and not being physically connected to each other and each not being physically connected to any other free piston to allow the two free pistons to move in opposite directions at the same time;
- at least one hydraulic plunger under each free piston, each hydraulic plunger in a respective hydraulic cylinder, the hydraulic cylinders being coupled to electronically controlled hydraulic cylinder valving;
- and
- a controller, the controller controlling the electronically controlled hydraulic cylinder valving to control the pair of free pistons to have substantially equal and opposite motions at the same time for each stroke of the of free pistons.
A method of operating a free piston engine comprising:
- providing a pair of free pistons in coaxial cylinders, the free pistons not being physically connected to each other and each not being physically connected to any other free piston;
- operating the free pistons in a compression ignition combustion cycle in equal and opposite directions at the same time;
- sensing compression ignition in each cylinder and making adjustments in engine operating conditions combustion cycle to combustion cycle for differences in ignition times and free piston positions at the time of ignition;
- and
- sensing pressure in each cylinder after compression ignition and making adjustments, combustion cycle to combustion cycle, in the ratio of fuel to balance the pressure profiles during the combustion stroke by adjusting the ratio of an amount of fuel injection or fuel intake in the two opposing cylinders, cycle to cycle.
Dependencies are inferred from the claim text.