US3733974A - Piston cylinder combination - Google Patents

Abstract

A cylinder separated into two opposed portions interconnected by an elongated gas passageway which is constantly heated at one end and constantly cooled at its opposite end. Gas is forced back and forth through the passageway by a free piston arranged within the cylinder portion between the heated passageway end and adjacent cylinder end and by a driven piston, connected to a power takeoff shaft and arranged in the opposite cylinder portion. The pistons have faces upon which are formed saw-tooth-like fins which mesh with corresponding fins formed in the cylinder at their respective passageway openings.

Description

United States Patent 11 1 Schuman [451 May 22, 1973 54 PISTON CYLINDER COMBINATION 3,583,155 6/1971 Schuman ..60/27 x 76 Inventor: Mark Schuman 101 G St. SW, A t. 1 A516, washingzon, DC 20024 p Prir tary Examiner-Martm P. Schwadron Assistant Exammer-Allen M. Ostrager Flledi 1971 Attorney-Lowe and King 21 A 1. No.: 127 600 1 pp 57 ABSTRACT Related Application Data A cylinder separated into two opposed portions inter- [62] Division of Ser. No. 861,256, Sept. 26, 1969, Pat. connected by an elongated gas passageway which is 3,533,155- constantly heated at one end and constantly cooled at its opposite end. Gas is forced back and forth through U.S. the passageway a free piston arranged the Cl- ..Fl6j cylinder ortion between the heated passageway end Fleld of Search 60/24, and adjacent cylinder end and a driven piston connected to a power take-off shaft and arranged in the inferences Clted opposite cylinder portion. The pistons have faces upon UNITED STATES PATENTS which are formed saw-tooth-like fins which mesh with corresponding fins formed in the cylinder at then 2,710,137 6/1955 Arnouil ..92/ 172 X respective passageway openings. 3,579,980 5/1971 Kelly ..60/24 734,220 7/1903 Bryan ..92/172 X 12 Claims, 9 Drawing Figures PATENIMAYMM SHEET 1 [IF 3 FIG. I

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INVENTOR MARK SCHUMAN wh wgfiam ATTORNEYS PATENIE 1m 2 21m SHEET 2 BF 3 INVENTCR MARK SCHUMAN ATTORNEYS PAT Emmmz I915 3,733 974 sum 3 OF 3 INVENTOR MARK SCHUMAN ATTORNEYS PISTON CYLINDER COMBINATION This application is a division of my earlier application, Ser. No. 861,256, filed Sept. 26, 1969, now US. Pat. No. 3,583,155.

FIELD OF INVENTION This invention relates to a oscillatory piston-cylinder device wherein mating cooling fins form a closure means for an elongated passageway.

SUMMARY OF INVENTION Summarizing, the invention herein contemplates driving a piston or a moving chamber wall in a cylinder with a compressible fluid that oscillates in an elongated passageway means having a closed, hot end and a cold end. The cold end forms a closure for the cylinder and passageways by intermeshing with the wall. The intermeshing wall and closure are shaped as fins for increasing gas movement and heat transfer within the cylinder, in order to provide maximum operating efficiency and economy and overall clean operation.

More specifically, the passageway means is closed at the hot end by a free piston located at the hot end of the cylinder, and is closed at the cold end by a variable volume cylinder space between the moving wall and the cold end of the passageway means. The wall is a driven piston coupled to a power take-off at the opposite cylinder end, with the two pistons being driven by compressible fluid that flows through the elongated passageway means'which are externally heated at the free piston end and cooled at the driven piston end for movement of heated and cooled gas respectively into the opposite passageway means ends for driving the driven and free pistons. The free piston is constantly oscillated and its oscillation or reciprocation is controlled for controlling the power output of the engine. Fins formed within the cylinder portions or spaces at the passageway ends, mesh with corresponding fins formed on their adjacent piston faces as the pistons oscillate to form variable geometry passageway portions, e.g. width, length and volume change.

These and other objects and advantages of this invention will become apparent upon reading the following description of which the attached drawings form a part.

DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional elevational view schematically showing one embodiment of the present invention.

FIG. 2 is a cross-sectional view taken in the direction of arrows 2-2 of FIG. 1.

FIG. 3 is an enlarged, fragmentary view of a portion of a piston and the cylinder wall.

FIG. 4 is an end view of the free piston.

FIG. 6 is a cross-sectional view taken in the direction of arrows 5-5 of FIG. 1.

FIGS. 6 through 9, inclusive, show steps in the operating cycle of the device for one particular set of valve adjustments.

DETAILED DESCRIPTION The device 10 is formed of an elongated, closed cylinder 11 containing a free piston 12 at one end and a driven piston 13 near the opposite end. The driven piston is connected by a pivot 14 to a connecting rod l5 in turn connected to a suitable flywheel 16 to which the power output shaft 17 is connected.

The middle of the cylinder, between the pistons, is blocked by a filler 20 which includes a number of elongated, spaced apart plates 21 each having gas passageways 22 extending therethrough. The plates are spaced apart and the gaps between them are blocked by end spacers 23 located at their upper and lower ends. Central spacers 24 divide the gaps between the plates into upper heating spaces 25 and lower cooling spaces 26.

Referring to FIG. 2, a suitable heat source 27 illustrated schematically as coils is connected by a heated fluid inlet 28 and outlet 29 into each of the upper heating spaces 25. The purpose is to heat the upper ends of the passageways by heating the plates near their upper ends. Such heating means, for example, could be in the form of a fossil fueled heater, heating a liquid circulated through the inlet 28, the heating spaces 25 and the outlet 29. Alternatively, coils could be placed within the heating spaces 25 for heating the upper ends of the plates and conveying fluid which has been heated. The particular form of heater may vary depending upon cost, availability and efficiency. For example, in some places a solar heater would be more economical whereas in other places an electrical type heater might be more economical.

Similarly, a cooling source 30, also schematically shown as coils, provides cooling liquid into the lower cooling spaces 26 through inlets '31 and out outlets 32. Any suitable and conventional cooling means can be used such as a refrigerating apparatus, cooled water in an available pool or body of water, air cooling, etc.

It is desirable to provide the maximum difference in temperature in heating source and cooling source, consistent with economics, and to provide substantially constant or uniform heat and cooling at the upper and lower ends of the passageways respectively, for a given power output.

Preferably, both the free piston 12 and the driven piston 13 are hollow with their exterior piston walls 35 being formed of a gas pervious material, such as sintered metals through which gas may leak. Thus, a gas bearing is formed between the walls of the pistons and the cylinder wall to avoid piston-cylinder contact and wear. Each piston is provided with a piston check valve 36 for receiving gas on its compression stroke, which in the case of the free piston is the bottom of its stroke and in the case of the driven piston is the top of its stroke. The check valves are otherwise closed.

In addition, the opposing faces of each of the pistons are bent or otherwise formed into V-shaped or sawtooth like fins or teeth 37. The end spacers 23 are correspondingly formed into mating or interfitting fins for meshing with the fins of the pistons and thereby considerably increasing the speed of heat transfer and the percentage of gas moved between the'opposed faces of the pistons, and therefore the ultimate efficiency of the device.

A pressurized surge tank 40 is provided outside of the cylinder and is connected by a pipe 41 to the space 42 above the free piston through an adjustable, springloaded throttle valve 43 of conventional construction. The tank is likewise connected through a pipe 44 to the space 45 below the free piston, through a similar throttle valve 46.

In addition, the surge tank 40 is also connected by a pipe 47 to the space 48 above the driven piston 13, again through the same type of throttle valve 49.

A by-pass or shunt pipe 51 connects the space 48 above the driven piston to the cylinder portion beneath the driven piston, with a spring loaded throttle valve 52 for adjusting the pressure of the gas above the driven piston. This affects the amount of gas undergoing the temperature cycle and thus the rate of converting ther mal engergy into mechanical energy. This may also be affected by the other throttle valves.

OPERATION The general operation of the engine is as follows: The free piston 12 reciprocates upwardly and downwardly, being driven upwards by the upward movement of the driven piston and the heating of the gas coming from space 45. As the free piston moves upwards it compresses the gas above it and below the top of the cylinder to the point where that compressed gas serves to drive the piston back downwardly again. Thus, in effect, the free piston is simply bounced up and down by the heated, compressed gas below it and by the gas which it itself has compressed above it. By adjusting the throttle valves 43 and46, the stroke of the free piston is controlled, particularly as to amplitude, by controlling the pressure from the pressurized surge tank. The surge tank pressure may be adjusted by the throttle valve 49.

On the downstroke of the free piston, the gas, due to the downward movement of the piston and the heating from heating spaces 25, is pushed and expands downwardly, at high pressure, into the space 48 above the driven piston which thereby drives the driven piston downwardly. The driven piston returns upwardly by the inertia of the flywheel 16 or by some other suitable mechanical mechanism, as is conventional in engines, and aided by the drop in pressure caused by cooling of the gas due to cooling spaces 26.

As can be seen, the gas reaching the finned face of the free piston is heated. When the gas is driven downwardly towards the driven piston, it is cooled at the lower ends of the passageways 22, thereby reducing the pressure between the pistons during the upstroke of the driven piston and increasing the pressure during the downstroke of the driven piston.

The two pistons generally are timed to operate on the same cycle of movements upwardly and downwardly, but normally the free piston will lag the driven piston some predetermined amount of the cycle, such as by one-quarter cycle.

FIGS. 6 through 9 illustrate successive steps in a single cycle of engine operation. FIG. 6 shows the driven piston 13, three-quarters of the way up on its upstroke. The free piston, lagging the driven piston by about onequarter cycle is half-way up on its upstroke. Gas (shown by arrows) is being forced upwardly through the passageways 22 into the space below the free piston 12, the gas being heated near the tops of the passageways.

At this portion of the cycle, the throttle valves 43, 46 and 49 are closed as is the check valve 52.

In FIG. 7, the driven piston 13 is one-quarter way down on its downstroke, while the free piston 12 is at its top dead center. At this point, the gas from the space 45 beneath the free piston is just beginning to flow back into the passageways 22 and downwardly. At this point,

throttle valve 46 is cracked open by its spring loading and some of the gas from space 45 flows into the surge tank 40, which in this example, is kept at a relatively low pressure.

In FIG. 8, the driven piston 13 is three-quarters of the way down on its downstroke and the free piston is halfway down on its downstroke. Now, the gas is freely flowing from the space 45 beneath the free piston through the passageways and into the space 48 above the driven piston, the gas being cooled as it passes through the lower ends of the passageways.

Here, the throttle valve 49 is open for flow of gas from the surge tank into the space 48 above the driven piston. Simultaneously, the throttle valve 52 has opened to permit gas to recharge the space 48 above the driven piston to the desired minimum pressure.

FIG. 9 shows the driven piston again on its upstroke, about one-quarter of the way up with the free piston at its bottom dead center. The pistons are so formed that they do not actually make contact between the mating fins but simply closely approach contact and this is done by proper dimensioning of the connecting rod 15 as well as by the pressure in the free piston end of the cylinder.

Here, the gas is now beginning to flow upwardly again. Throttle valve 43 is opened by means of its spring loading to permit gas flow as shown by the arrows. The throttle valves 49 and 52 are about to close. Cooling of the gas in the space 48 reduces the pressure on the driven piston during its upstroke.

The cycle repeats itself in the usual fashion in the manner as described above.

A higher pressure stored in the surge tank 40 and applied by means of valves 43 and 46 to the gas trapped in spaces 42 and 45, above and below the free piston, would affect the amplitude of oscillation of the free piston, the amount of gas undergoing the temperature cycle and therefore, the power output.

A change in the pressure of gas trapped in space 42 relative to that trapped in space 45 will cause an upward or downward shift in the mean position of the free piston, and likewise will affect the power output.

Having fully described an operative embodiment of this invention, I now claim:

1. An oscillatory device comprising a variable volume chamber having closure means, an oscillating wall of the chamber reciprocating toward and away from the closure means, fluid passageway means including at least one elongated fluid passageway opening near one end into a space of the chamber between the wall and the closure means, said passageway means being closed at the other end so that the fluid flows in the passageway means toward and away from the variable volume chamber are substantially the same during each oscillation cycle of the wall; at least one axially elongated, saw-toothed like fin formed on at least one of said closure means and on a face of said wall, said wall facing said closure means.

2. A construction as defined in claim 1 wherein the volume of the passageway varies during the oscillatory cycle.

3. In combination, a variable volume chamber, said chamber having an oscillating wall and a mating chamber wall portion facing the oscillating wall, fluid passageway means having an opening near one end through said wall portion into said chamber and a secand closed end, said oscillating wall oscillating toward and away from said mating wall portion to compress compressible fluid in a portion of the passageway means remote from the mating chamber wall portion and to be subsequently driven by compressible fluid subsequently flowing in the passageway means into the chamber, and at least one cooling fin extending into the chamber from at least one of the oscillating wall and the chamber wall portion facing the oscillating wall.

4. The device of claim 1 wherein the volume of the passageway means varies during the oscillatory cycle.

5. The device of claim 1 wherein the saw-tooth like fin is a cooling fin.

6. A reciprocating piston-cylinder construction comprising a cylinder having an oscillatory reciprocating free piston fitted therein, one face of the piston being formed with axially elongated, saw-tooth like fins; the cylinder having a closure means having a face formed with corresponding saw-tooth like fins arranged to fit between and mesh with the adjacent piston fins; the piston fins being moved toward and away from the closure means fins as the piston reciprocates for meshing therewith.

7. The device of claim 1 wherein the fluid passageway means is formed in said closure means.

8. The device of claim 1 wherein the elongated passageway extends longitudinally in the same direction as the piston reciprocates.

9. The device of claim 7 wherein the passageway means includes a block containing the at least one passageway, said block being stationary relative to said cylinder.

10. The device of claim 1 wherein both said wall and said closure means include saw-tooth like fins, said fins mating during reciprocation of the wall while the wall and closure means are proximate.

11. An oscillatory device comprising a variable volume chamber having closure means, an oscillating free piston having a face reciprocating toward and away from the closure means, fluid passageway means including at least one elongated fluid passageway opening near one end into a space of the chamber between the face and the closure means, said passageway means being closed at the other end so that the fluid flows in the passageway means toward and away from the variable volume chamber are substantially the same during each oscillation cycle of the wall; at least one axially elongated, saw-tooth like fin formed on at least one of said closure means and on said face, said face facing said closure means.

12. The device of claim 11 wherein both said face and said closure means include saw-tooth like fins, said fins mating during reciprocation of the face while the face and closure means are proximate.

Claims (12)

1. An oscillatory device comprising a variable volume chamber having closure means, an oscillating wall of the chamber reciprocating toward and away from the closure means, fluid passageway means including at least one elongated fluid passageway opening near one end into a space of the chamber between the wall and the closure means, said passageway means being closed at the other end so that the fluid flows in the passageway means toward and away from the variable volume chamber are substantially the same during each oscillation cycle of the wall; at least one axially elongated, saw-toothed like fin formed on at least one of said closure means and on a face of said wall, said wall facing said closure means.

2. A construction as defined in claim 1 wherein the volume of the passageway varies during the oscillatory cycle.

3. In combination, a variable volume chamber, said chamber having an oscillating wall and a mating chamber wall portion facing the oscillating wall, fluid passageway means having an opening near one end through said wall portion into said chamber and a second closed end, said oscillating wall oscillating toward and away from said mating wall portion to compress compressible fluid in a portion of the passageway means remote from the mating chamber wall portion and to be subsequently driven by compressible fluid subsequently flowing in the passageway means into the chamber, and at least one cooling fin extending into the chamber from at least one of the oscillating wall and the chamber wall portion facing the oscillating wall.

4. The device of claim 1 wherein the volume of the passageway means varies during the oscillatory cycle.

5. The device of claim 1 wherein the saw-tooth like fin is a cooling fin.

6. A reciprocating piston-cylinder construction comprising a cylinder having an oscillatory reciprocating free piston fitted therein, one face of the piston being formed with axially elongated, saw-tooth like fins; the cylinder having a closure means having a face formed with corresponding saw-tooth like fins arranged to fit between and mesh with the adjacent piston fins; the piston fins being moved toward and away from the closure means fins as the piston reciprocates for meshing therewith.

7. The device of claim 1 wherein the fluid passageway means is formed in said closure means.

8. The device of claim 1 wherein the elongated passageway extends longitudinally in the same direction as the piston reciprocates.

9. The device of claim 7 wherein the passageway means includes a block containing the at least one passageway, said block being stationary relative to said cylinder.

10. The device of claim 1 wherein both said wall and said closure means include saw-tooth like fins, said fins mating during reciprocation of the wall while the wall and closure means are proximate.

11. An oscillatory device comprising a variable volume chamber having closure means, an oscillating free piston having a face reciprocating toward and away from the closure means, flUid passageway means including at least one elongated fluid passageway opening near one end into a space of the chamber between the face and the closure means, said passageway means being closed at the other end so that the fluid flows in the passageway means toward and away from the variable volume chamber are substantially the same during each oscillation cycle of the wall; at least one axially elongated, saw-tooth like fin formed on at least one of said closure means and on said face, said face facing said closure means.

12. The device of claim 11 wherein both said face and said closure means include saw-tooth like fins, said fins mating during reciprocation of the face while the face and closure means are proximate.

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