Piston-in-piston variable compression ratio engine
AssigneeThe United States of America as represented by the Administrator of the United States Environmental Protection Agency
InventorCharles L. Gray, Jr.
Life of this patent
Estimating the term…
Abstract
An improved apparatus for generating a variable compression ratio within an ICE includes a piston-in-piston assembly having an inner piston that is slidably mounted within an outer piston and coupled to an actuator. The actuator is further coupled to a fluid source, and a volume of fluid is selectively channeled into and out of the actuator to move the inner piston to selected positions corresponding to desired compression ratios. At top dead center, a top face of the outer piston maintains a substantially constant distance from an engine head assembly to minimize squish area variations.
Claims61
A piston assembly positionable in an internal combustion engine, the piston assembly comprising:
- an outer piston;
- an inner piston having a combustion surface;
- an actuator coupled to the inner piston;
- and
- wherein the inner piston is slidably mounted within the outer piston and selectively moveable by the actuator, and the outer piston and the actuator are directly attached to the wrist pin.
A method of generating a variable compression ratio in an internal combustion engine comprising:
- selectively sliding an inner piston within an outer piston;
- positioning a top surface of the inner piston at a first position;
- channeling fluid into an actuator coupled to the inner piston to move the inner piston to a second position wherein the top surface at the second position is lower than the top surface at the first position;
- sending a first command signal to a control valve coupled to a fluid source to start a flow of fluid, thereby moving the inner piston to the second position;
- and
- sending a second command signal to the control valve to stop the flow of fluid, thereby moving the inner piston to the first position.
A piston assembly positionable in an internal combustion engine, the piston assembly comprising an inner piston and an outer piston, the inner piston being slidably mounted within the outer piston and selectively moveable by an actuator comprising a cam coupled to a spring, the spring biasing the inner piston in a first position.
A piston assembly positionable in an internal combustion engine, the piston assembly comprising an inner piston and an outer piston, the inner piston being slidably mounted within the outer piston and selectively moveable by an actuator comprising a cam having a plurality of bearing surfaces, the cam being coupled to the inner piston and the inner piston being selectively supported by the bearing surfaces as the cam rotates.
A piston assembly positionable in an internal combustion engine, the piston assembly comprising an inner piston and an outer piston, the inner piston being slidably mounted within the outer piston and selectively moveable by a cam coupled to the inner piston and to a hydraulic chamber, a volume of fluid being selectively channeled into the chamber to rotate the cam in a first direction to move the inner piston to a second position and selectively removed from the chamber to rotate the cam in a second direction to allow the inner piston to return to a first position.
A piston assembly positionable in an internal combustion engine comprising:
- an outer piston;
- an inner piston slidably mounted within the outer piston and selectively moveable by an actuator comprising a hydraulic piston provided in a hydraulic chamber and coupled to the inner piston;
- and
- a fluid delivery system adapted to be coupled to a fluid source to selectively channel a volume of fluid into the actuator to move the inner piston to a first position and selectively remove the fluid from the actuator to move the inner piston to a second position, the volume of fluid displacing the hydraulic piston to move the inner piston and thereby actuate the inner piston.
An apparatus for generating a variable compression ratio in an internal combustion engine comprising:
- an outer piston;
- an inner piston slidably mounted within the outer piston;
- a wrist pin rigidly embedded in the outer piston;
- a cam assembly pivotably mounted on the wrist pin and coupled to the inner piston, the cam assembly selectively moving the inner piston to a desired position within the outer piston;
- and
- wherein a distance between a top surface of the outer piston and a bottom surface of a cylinder head when the piston assembly is positioned at top dead center remains substantially constant, independent of a location of the inner piston.
A method of generating a variable compression ratio in an internal combustion engine comprising:
- positioning an inner piston in a first position within an outer piston, the inner and the outer piston being placed within a cylinder of an internal combustion engine, the inner and the outer piston compressing a first volume of air within the cylinder, the first position causing the cylinder to function at a first compression ratio;
- selectively moving the inner piston to a second position within the outer piston, the inner and the outer piston compressing a second volume of air within the cylinder, the second position causing the cylinder to function at a second compression ratio;
- and
- selectively channeling a volume of fluid into and out of an actuator coupled to the inner piston to move the inner piston.
A piston assembly positionable in an internal combustion engine, the piston assembly comprising:
- an outer piston;
- an inner piston having a combustion surface;
- an actuator comprising a cam coupled to a spring;
- and
- wherein the actuator is coupled to the inner piston, the inner piston is slidably mounted within the outer piston and selectively moveable by the actuator, and the spring is coupled to the inner piston to bias the inner piston in a first position.
A piston assembly positionable in an internal combustion engine, the piston assembly comprising:
- an outer piston;
- an inner piston having a combustion surface;
- an actuator comprising a cam having a plurality of bearing surfaces;
- and
- wherein the actuator is coupled to the inner piston the inner piston is slidably mounted within the outer piston and selectively moveable by the actuator, and the inner piston is selectively supported by the bearing surfaces as the cam rotates.
A method of generating a variable compression ratio in an internal combustion engine comprising:
- positioning an inner piston in a first position within an outer piston, the inner and the outer piston being placed within a cylinder of an internal combustion engine, the inner and the outer piston compressing a first volume of air within the cylinder, the first position causing the cylinder to function at a first compression ratio;
- holding the inner piston substantially in the first position;
- monitoring operating conditions of the internal combustion engine;
- selectively moving the inner piston to a second position within the outer piston at a selected point in time, the inner and the outer piston compressing a second volume of air within the cylinder, the second position causing the cylinder to function at a second compression ratio;
- and
- selectively holding the inner piston substantially in the second position.
A piston assembly positionable in an internal combustion engine, the piston assembly comprising:
- an outer piston;
- an inner piston having a combustion surface;
- an actuator coupled to the inner piston and to a fluid source;
- and
- wherein the inner piston is slidably mounted within the outer piston and selectively moveable by the actuator, and a volume of fluid is selectively channeled into the actuator to move the inner piston to a second position and selectively removed from the actuator to allow the inner piston to move to a first position.
A piston assembly positionable in an internal combustion engine comprising:
- an outer piston;
- an inner piston slidably mounted within the outer piston and selectively moveable by an actuator coupled to the inner piston;
- and
- a fluid delivery system adapted to be coupled to a fluid source to selectively channel a volume of fluid into the actuator to move the inner piston to a first position and selectively remove the fluid from the actuator to move the inner piston to a second position, thereby actuating the inner piston.
An apparatus for generating a variable compression ratio in an internal combustion engine comprising:
- an outer piston;
- an inner piston slidably mounted within the outer piston;
- a wrist pin rigidly embedded in the outer piston;
- a cam assembly pivotably mounted on the wrist pin and coupled to the inner piston;
- a control system that monitors operating conditions and selectively generates a command signal;
- and
- wherein the cam assembly selectively moves the inner piston to a desired position within the outer piston in response to the command signal.
An internal combustion engine having a variable compression ratio comprising:
- an outer piston;
- an inner piston slidably mounted within the outer piston;
- a wrist pin rigidly embedded in the outer piston;
- a cam assembly coupled to the wrist pin and the inner piston to selectively move the inner piston within the outer piston from a first position to a second position;
- and
- a fluid delivery system coupled to the cam assembly, wherein a volume of fluid is selectively channeled to and from the cam assembly to move the inner piston from the first position to the second position.
Dependencies are inferred from the claim text.