US4215548A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Free-piston regenerative hot gas hydraulic engine
Assignee: National Aeronautics and Space Administration
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Filing: 1978-10-12
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Granted: 1980-08-05
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Expires: 1998-10-12
Abstract
Abstract The present invention is directed to a free-piston regenerative hydraulic engine including a displacer piston which is driven pneumatically by a high-pressure or low-pressure gas. Actuation of the displacer piston circulates the working fluid through a heater, a regenerator and a cooler. The present invention includes an inertial mass such as a piston or a hydraulic fluid column to effectively store and supply energy during portions of the cycle. Power is transmitted from the working fluid to a hydraulic fluid across a diaphragm or lightweight piston to achieve a hydraulic power output. The displacer piston of the present invention may be driven pneumatically, hydraulically or electromagnetically. In addition, the displacer piston and the inertial mass of the present invention may be positioned on the same side of the diaphragm member or may be separated by the diaphragm member.
Inventors
- 👤 Donald G. Beremand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:30
CPC Classifications
F; F02; F02G; F02G1/00; F02G1/04; F02G1/043; F02G1/045; F02G1/05; F01; F01B; F01B11/00; F01B11/04; F01B19/00; F01B19/02; F02G1/0435
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
198 words
A free-piston regenerative engine comprising: a piston chamber including an upper portion, a lower portion and a bottom; a displacer piston slidably mounted to move through a stroke within said upper portion of said piston chamber, said displacer piston including a top surface area and a bottom surface area; a heater, a regenerator and a cooler in communication with said piston chamber and being referenced to the top surface area and the bottom surface area of said displacer piston; means for imparting motion to the displacer piston; an inertial piston slidably mounted within said piston chamber; a diaphragm positioned to move through a stroke at a lower portion of said piston chamber wherein a fluid chamber is defined between the diaphragm and said bottom of said piston chamber; whereby fluid is supplied to and discharged from said fluid chamber in response to the movement of said displacer piston; and said displacer piston remaining stationary for a predetermined period of time at the end of said stroke to allow the diaphragm to complete its stroke prior to reversing the motion of said displacer piston, and wherein varying said predetermined period of time varies the engine frequency and output power.
Claim 2
Dependent Claim
198 words
A free-piston regenerative engine comprising: a piston chamber including an upper portion, a lower portion and a bottom; a displacer piston slidably mounted to move through a stroke within said upper portion of said piston chamber, said displacer piston including a top surface area and a bottom surface area; a heater, a regenerator and a cooler in communication with said piston chamber and being referenced to the top surface area and the bottom surface area of said displacer piston; means for imparting motion to the displacer piston; an inertial piston slidably mounted within said piston chamber; a diaphragm positioned to move through a stroke at a lower portion of said piston chamber wherein a fluid chamber is defined between the diaphragm and said bottom of said piston chamber; whereby fluid is supplied to and discharged from said fluid chamber in response to the movement of said displacer piston; and said displacer piston remaining stationary for a predetermined period of time at the end of said stroke to allow the diaphragm to complete its stroke prior to reversing the motion of said displacer piston, and wherein varying said predetermined period of time varies the engine frequency and output power.
Claim 3
Dependent Claim
29 words
A free-piston regenerative engine according to claim 1, wherein movement of said displacer piston displaces a working fluid contained within said piston chamber through said heater, regenerator and cooler.
Claim 4
Dependent Claim
32 words
A free-piston regenerative engine according to claim 2, wherein the displacement of said working fluid through said heater, regenerator and cooler cyclically transfers heat to and withdraws heat from the working fluid.
Claim 5
Dependent Claim
52 words
A free-piston regenerative engine according to claim 1, wherein said means for imparting motion to the displacer piston comprises a supply of high pressure and a supply of low pressure alternately supplied to an intermediate surface area of said displacer piston positioned between said top surface area and said bottom surface area.
Claim 6
Dependent Claim
19 words
A free-piston regenerative engine according to claim 4, wherein said supply of high pressure and low pressure is pneumatic.
Claim 7
Dependent Claim
19 words
A free-piston regenerative engine according to claim 4, wherein said supply of high pressure and low pressure is hydraulic.
Claim 8
Dependent Claim
19 words
A free-piston regenerative engine according to claim 1, including an electromagnetic means for imparting motion to the displacer piston.
Claim 9
Dependent Claim
22 words
A free-piston regenerative engine according to claim 4, wherein said supply of high pressure and low pressure is generated by said engine.
Claim 10
Dependent Claim
27 words
A free-piston regenerative engine according to claim 1, wherein said displacer piston and said inertial piston are positioned adjacent each other one one side of said diaphragm.
Claim 11
Dependent Claim
21 words
A free-piston regenerative engine according to claim 1, wherein said displacer piston is separated from said inertial piston by said diaphragm.
Claim 12
Dependent Claim
134 words
A free-piston regenerative engine comprising: a piston chamber including an upper portion, a lower portion and a bottom; a displacer piston slidably mounted within said upper portion of said piston chamber, said displacer piston includes a top surface area and a bottom surface area; a heater, a regenerator and a cooler in communication with said piston chamber and being referenced to the top surface area and the bottom surface area of said displacer piston; means for imparting motion to the displacer piston; and a diaphragm positioned at a lower portion of said piston chamber wherein a fluid chamber is defined between the diaphragm and said bottom of said piston chamber; whereby fluid supplied to and discharged from said fluid chamber in response to the movement of said displacer piston functions as an inertial mass.
Claim 13
Dependent Claim
134 words
A free-piston regenerative engine comprising: a piston chamber including an upper portion, a lower portion and a bottom; a displacer piston slidably mounted within said upper portion of said piston chamber, said displacer piston includes a top surface area and a bottom surface area; a heater, a regenerator and a cooler in communication with said piston chamber and being referenced to the top surface area and the bottom surface area of said displacer piston; means for imparting motion to the displacer piston; and a diaphragm positioned at a lower portion of said piston chamber wherein a fluid chamber is defined between the diaphragm and said bottom of said piston chamber; whereby fluid supplied to and discharged from said fluid chamber in response to the movement of said displacer piston functions as an inertial mass.
Claim 14
Dependent Claim
29 words
A free-piston regenerative engine according to claim 11, wherein movement of said displacer piston displaces a working fluid contained within said piston chamber through said heater, regenerator and cooler.
Claim 15
Dependent Claim
32 words
A free-piston regenerative engine according to claim 12, wherein the displacement of said working fluid through said heater, regenerator and cooler, cyclically transfers heat to and withdraws heat from the working fluid.
Claim 16
Dependent Claim
52 words
A free-piston regenerative engine according to claim 11, wherein said means for imparting motion to the displacer piston comprises a supply of high pressure and a supply of low pressure alternately supplied to an intermediate surface area of said displacer piston positioned between said top surface area and said bottom surface area.
Claim 17
Dependent Claim
19 words
A free-piston regenerative engine according to claim 14, wherein said supply of high pressure and low pressure is pneumatic.
Claim 18
Dependent Claim
19 words
A free-piston regenerative engine according to claim 14, wherein said supply of high pressure and low pressure is hydraulic.
Claim 19
Dependent Claim
19 words
A free-piston regenerative engine according to claim 11, including an electromagnetic means for imparting motion to the displacer piston.
Claim 20
Dependent Claim
22 words
A free-piston regenerative engine according to claim 14, wherein said supply of high pressure and low pressure is generated by said engine.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-05 | 1984-02-04 | 1984-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-05 | 1988-02-04 | 1988-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-05 | 1992-02-04 | 1992-08-05 | $7700.00 | Window Closed / Lapsed |