US3708979A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuital flow hot gas engines
Assignee: Massachusetts Institute of Technology
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Filing: 1971-04-12
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Granted: 1973-01-09
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Expires: 1991-04-12
Abstract
Abstract A compressor, heater, expander and cooler are connected to form a closed circuit. Valves control the pulsating flow of a working gas about this circuit. An interchanger may be included in the circuit to allow use of a low expansion ratio with a high ratio of extreme temperatures. Relatively large volumes of heater and cooler may be used. Power output is controlled by altering valve timing. Alternately, power output may be controlled by the use of auxiliary chambers and altering the mass of working gas in the circuit.
Inventors
- 👤 V Bush
- 👤 J Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:01
CPC Classifications
F; F02; F02G; F02G1/00; F02G1/04; F02G1/043; F02G2244/00; F02G2244/50; F02G2258/00; F02G2258/10; F02G2270/00; F02G2270/50
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
56 words
A hot gas engine comprising a compressor, a heater, an expander, and a cooler in closed circuit connection, valves in the circuit to control flow of working gas in the circuit, and variable control means connected to at least one of the valves for varying operation of the valves and thereby varying output of the engine.
Claim 2
Dependent Claim
56 words
A hot gas engine comprising a compressor, a heater, an expander, and a cooler in closed circuit connection, valves in the circuit to control flow of working gas in the circuit, and variable control means connected to at least one of the valves for varying operation of the valves and thereby varying output of the engine.
Claim 3
Dependent Claim
43 words
The hot gas engine of claim 1 wherein the expander is a cyclically variable volume chamber, and wherein the control means is connected to the chamber for selectively controlling timing of the valves in varied relation to cyclical variations of the chamber volume.
Claim 4
Dependent Claim
25 words
The hot gas engine of claim 1 wherein the variable control means is connected to an expander exhaust valve between the expander and the cooler.
Claim 5
Dependent Claim
25 words
The hot gas engine of claim 3 wherein the variable control means is connected to an expander intake valve between the heater and the expander.
Claim 6
Dependent Claim
25 words
The hot gas engine of claim 1 wherein the variable control means is connected to an expander intake valve between the heater and the expander.
Claim 7
Dependent Claim
25 words
The hot gas engine of claim 1 wherein the variable control means is connected to a compressor intake valve between the cooler and the compressor.
Claim 8
Dependent Claim
25 words
The hot gas engine of claim 6 wherein the variable control means is connected to an expander exhaust valve between the expander and the cooler.
Claim 9
Dependent Claim
25 words
The hot gas engine of claim 6 wherein the variable control means is connected to an expander intake valve between the heater and the expander.
Claim 10
Dependent Claim
20 words
The hot gas engine of claim 8 wherein the variable control means is connected to expander intake and exhaust valves.
Claim 11
Dependent Claim
43 words
The hot gas engine of claim 1 further comprising a shaft connected to the expander and wherein at least one of the valves comprises a pilot valve, and wherein the variable control means comprises a variable pilot valve operator connected to the shaft.
Claim 12
Dependent Claim
48 words
The hot gas engine of claim 1 further comprising an interchanger in the circuit between the expander and cooler and the compressor and heater for removing heat from gas flowing between the expander and the cooler and transferring heat to gas flowing between the compressor and the heater.
Claim 13
Dependent Claim
23 words
The hot gas engine of claim 11 further comprising a valve controlled interchanger bypass in the circuit between the expander and the cooler.
Claim 14
Dependent Claim
59 words
In hot gas energy conversion apparatus having sequentially connected heater means, expander means, and compressor means for flowing gas between the means and repeatedly heating, expanding and compressing gas and thereby converting energy, the improvement comprising variable valve means connected between at least two sequentially connected means for varying gas flow between the means and for varying energy conversion.
Claim 15
Dependent Claim
59 words
In hot gas energy conversion apparatus having sequentially connected heater means, expander means, and compressor means for flowing gas between the means and repeatedly heating, expanding and compressing gas and thereby converting energy, the improvement comprising variable valve means connected between at least two sequentially connected means for varying gas flow between the means and for varying energy conversion.
Claim 16
Dependent Claim
38 words
The apparatus of claim 13 wherein the variable valve means comprises variable expander intake valve means connected between the heater means and the expander means for selectively varying amount of gas which is expanded in the expander means.
Claim 17
Dependent Claim
40 words
The apparatus of claim 14 whereiN the variable valve means further comprises variable expander exhaust valve means connected between the expander means and the compressor means for varying the period of gas flow to the cooler from the expander means.
Claim 18
Dependent Claim
29 words
The apparatus of claim 15 further comprising check valve means connected between the compressor means and the heater means for permitting free flow of gas toward the heater means.
Claim 19
Dependent Claim
67 words
The apparatus of claim 15 wherein the expander means comprises cylinder and piston means, and further comprising shaft means connected to the piston means for receiving energy therefrom, and first and second variable valve operating means connected to the shaft means and respectively connected to the expander intake and exhaust valve means for varying timing of the valve means in relation to movement of the piston means.
Claim 20
Dependent Claim
31 words
The apparatus of claim 13 further comprising cooler means sequentially connected between the expander means and the compressor means for cooling gas flowing between the expander means and the compressor means.
Claim 21
Dependent Claim
93 words
An engine valve operator comprising a piston connected to an engine valve, a cylinder forming a chamber with the piston, a gas line connected to the chamber, a pilot valve connected to the gas line, an operator connected to the pilot valve, and connected to an engine shaft, a pressure reservoir connected to the pilot valve for supplying pressurized gas through the pilot valve to the chamber for driving the piston and changing state of an engine valve in a timing sequence in relation to the engine shaft as controlled by the operator.
Claim 22
Dependent Claim
93 words
An engine valve operator comprising a piston connected to an engine valve, a cylinder forming a chamber with the piston, a gas line connected to the chamber, a pilot valve connected to the gas line, an operator connected to the pilot valve, and connected to an engine shaft, a pressure reservoir connected to the pilot valve for supplying pressurized gas through the pilot valve to the chamber for driving the piston and changing state of an engine valve in a timing sequence in relation to the engine shaft as controlled by the operator.
Claim 23
Dependent Claim
21 words
The apparatus of claim 19 wherein the operator has a selectively variable size for selectively varying dwell of the engine valve.
Claim 24
Independent Claim
28 words
The method of operating a hot gas engine comprising compressing, heating, expanding and cooling working gas and variably controlling flow of the working gas in a closed circuit.
Claim 25
Independent Claim
28 words
The method of operating a hot gas engine comprising compressing, heating, expanding and cooling working gas and variably controlling flow of the working gas in a closed circuit.
Claim 26
Dependent Claim
23 words
The method of claim 21 wherein the controlling comprises varying flow of working gas to an expander and thereby varying the expanding step.
Claim 27
Dependent Claim
24 words
The method of claim 22 wherein the controlling step comprises varying flow of working gas from an expander and thereby varying the expanding step.
Claim 28
Dependent Claim
24 words
The method of claim 21 wherein the controlling step comprises varying flow of working gas from an expander and thereby varying the expanding step.
Claim 29
Dependent Claim
21 words
The method of claim 21 wherein the controlling step comprises varying inward flow to a compressor, thereby varying the compressing step.
Claim 30
Dependent Claim
27 words
The method of claim 25 wherein the controlling step comprises varying flow of working gas to an expander and from an expander, thereby varying the expanding step.
Claim 31
Dependent Claim
69 words
The method of claim 21 wherein the controlling step comprises opening an expander intake valve and admitting gas during a portion of expansion of a cyclically variable expansion chamber, closing the intake valve at varied points in expansion of the chamber and expanding the gas during completion of the expansion of the chamber, and operating the expander intake valve in timed relationship with the cyclic variation of the chamber.
Claim 32
Dependent Claim
55 words
The method of claim 21 wherein the expanding step comprises cyclically varying an expander volume, and wherein the controlling step comprises opening an expander exhaust valve at a volumetrically cyclic point between before reaching maximum expander volume and before reaching minimum expander volume and holding the expander exhaust valve open until about minimum expander volume.
Claim 33
Dependent Claim
64 words
The method of claim 21 wherein the compressing step comprises cyclically varying a compressor volume, and wherein the controlling step comprises opening an intake valve in a compressor at about minimum compressor volume, holding the compressor intake valve open, and selectively closing the compressor intake valve between a cyclical point before reaching maximum compressor volume and a cyclical point after passing maximum compressor volume.
Claim 34
Dependent Claim
95 words
The method of claim 29 wherein the expanding step comprIses cyclically varying an expander volume, and wherein the controlling step further comprises opening an expander intake valve at about minimum expander volume, holding the expander intake valve open, selectively closing the expander intake valve at a variable cyclic point between minimum and maximum expander volume, selectively opening an expander exhaust valve at a variable cyclic point between the closing of the expander intake valve and before reaching minimum expander volume holding the exhaust valve open and closing the exhaust valve at about minimum expander volume.
Claim 35
Dependent Claim
23 words
The method of claim 21 wherein the controlling step comprises changing open periods of the expander and compressor intake valves thereby changing power.
Claim 36
Dependent Claim
20 words
The method of claim 31 wherein the controlling step comprises maintaining a constant ratio of expander and compressor active volumes.
Claim 37
Dependent Claim
37 words
The method of claim 21 wherein the controlling step comprises changing open periods of the expander and compressor intake valves, permitting free exhaust from the compressor and permitting free exhaust from the expander during limited cyclic periods.
Claim 38
Independent Claim
48 words
The method of hot gas energy conversion comprising flowing working gas through a compressor, heater and expander and cooler, removing working gas between the cooler and compressor to reduce power, storing working gas at high pressure, and adding working gas between the compressor and heater to increase power.
Claim 39
Independent Claim
48 words
The method of hot gas energy conversion comprising flowing working gas through a compressor, heater and expander and cooler, removing working gas between the cooler and compressor to reduce power, storing working gas at high pressure, and adding working gas between the compressor and heater to increase power.
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) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |