United States Patent [191' [11] Patent Number: 4,864,826 Lagow [45] Date of Patent: Sep. 12, 1989

[54] METHOD AND APPARATUS FOR 4,156,343 5/1979 Stewart . GENERATING POWER FROM A VAPOR 4,209,992 7/1980 chlh'Kang - 4,285,201 8/1981 Stewart . [76] Inventor: Ralph J. Lagow, 2511-B NASA Rd. 4,354,565 10/1932 Latter er a1, , 1, Ste. 102, Seabrook, Tex. 77586 4,424,678 1/1984 Kizziah . 4,603,554 8/ 1986 Lagow . [21] APPI- N°-= 36,891 4,693,087 9/1987 Lagow ...... 60/692 x [221 Fi1ed= Aug- 18’ 1987 FOREIGN PATENT DOCUMENTS Related U_S_ Application Data 20771 5/1882 Fed. Rep. of Germany . ' 41477 4/ 1887 Fed. Rep. of Germany . [63] Continuation-impart of Ser. No. 844,583, Mar. 27, 46619 5/1889 Fed, Rep, of Germany _ 1986, Pat, N0. 4,693,087, which 15 a eontinuation-in- 51433 6/1889 Fed_ Rep, of Germany , part of Ser. No. 664,792, Oct. 25, 1984, Pat. No. 132091 3/1929 Switzerland _ 4,603,554. ‘ 140063 of 1919 United Kingdom . [51] Int. Cl.4 ...... F01K 11/00; F01K 21/00 OTHER PUBLIC ATIQNS [52] US. Cl...... 60/670; 60/669;6o/692 Skinner_ Reeiproeating, _ Steam Engines,_ reprinted_ from [58] Field of Search ...... 60/651, 670, 671, 669, Mame Engmeenng/L0g (11° date gm“) 60/690’ 692’ 508’ 509, 512, 515 Skinner’s High Efficiency Compound Engine, Reprint _ from Marine Propulsion International (no date given). [56] References C‘ted Catalog entitled, “Skinner Marine Conversion Unit” U.S. PATENT DOCUMENTS (no date given). 130,685 8/ 1872 Adams . Primary Examiner-Allen M. Ostrager 451,342 4/1891 Susini . Attorney, Agent, or Firm-—Arnold, White & Durkee 514,573 2/ 1894 Susini . 670,829 3/1901 Windhausen . [57] ABSTRACT 756,785 4/ 1904 Fraley . There is provided an apparatus and method for generat 982,449 1/ 191 1 Timmins . 3,287,901 11/1966 Tauer . ing power from a working ?uid wherein the working 3,531,933 10/1970 Baldwin . fluid is a saturated vapor or superheated vapor gener 3,950,949 4/ 1976 Martin et a1. . ated in a high pressure zone where the working ?uid is 3,967,450 7/ 1976 Girardier . used to impart work to a working shaft by means of 4,018,581 4/ 1977 Ruff et al. . directly linked high and low pressure cylinder piston 4,033,136 7/ 1977 Stewart . assemblies located in the high pressure zone and a lower 4,068,476 l/ 1978 Kelsey . 4,102,133 7/1978 Anderson . pressure zone, respectively. 4,106,581 8/1978 West et a1. . 4,109,468 8/ 1978 Heath . 9 Claims, 14 Drawing Sheets US. Patent Sep. 12,1989 Sheet 1 of 14 4,864,826 US. Patent _Sep. 12, 1989 Sheet 2 of 14 4,864,826

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US. Patent Sep. 12, 1989 Sheet 6 0f 14 4,864,826

( REJECTION FIG.7 VALVE OPENS CORRECTED WEIGHT FLOW REJECTION W VALVE C LOS E S

CRITICAL (PC) llllllilllllll 1(MAX.) O(MIN.) LOW/HIGH PRESSURE RATIO (P) CI-IOKED UNCHOKED FLOW .I. FLOW

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WASTE DIRECT HEAT FIG-I2 HE AT (NAT URAL GAS) 310 312

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(T)TEMPERATURE 402

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Fig; 1a CONDUCTION HEAT LOSS/ @ TANDEM COMPOUND CONDENSING ENGINE GAIN COMPARISON (CYLINDER A8. B TORLON) @ PRESENT VAPOR POWER ACTUATED GEN. SYSTEM (CYLINDER A8,B TORLONI @ PRESENT VAPOR POWER ACTUATED GEN.SYSTEM CC YY UL Nm DD EE RR AB \.1 CT 00 PR PL E0 RN US. Patent Sep.12,1989 Sheet 13 of 14 4,864,826

7Au5 O _ 59379 WORK OUTPUT (CYL.“A")

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0 30 6O 90 T20 T50 T80 2T0 2L0 270 300 330 360 CRANK ANGLE (DEGREES) US. Patent Sep. 12,1989 Sheet 14 of 14 4,864,826

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3 1% w CRANK ANGLE (DEGREES) 4,864,826 1 2 working ?uid from the ideal as well as frictional, rota METHOD AND APPARATUS FOR GENERATING tional and other losses, such as due to leakage. Further POWER FROM A VAPOR inefficiencies can result from the con?guration of the particular process. These may include one or more of BACKGROUND OF THE INVENTION 5 several inef?ciencies for a given cycle or engine. For This is a continuation-in-part of a patent application, example, many devices fail to develop a suf?cient mean Ser. No. 844,583 ?led Mar. 27, 1986 entitled METHOD effective pressure. Here, the term “mean effective pres OF GENERATING POWER FROM A VAPOR U.S. sure” may be defined as the pressure which, if acted on Pat. No. 4,693,087 which is a continuation-in-part of a piston during the entire power stroke, would do an patent application, Ser. No. 664,792 ?led Oct. 25, 1984 amount of work equal to that actually done on the pis now U.S. Pat. No. 4,603,554 entitled METHOD AND ton. The work for one cycle is found by multiplying this APPARATUS FOR EXTRACTING USEFUL EN mean effective pressure by the area of the piston and by ERGY FROM A SUPERHEATED VAPOR ACTU the stroke’s length. ATED POWER GENERATING DEVICE. In other devices the maximum pressure differential The past two hundred years have seen the develop occurs at less than favorable crank angles for exerting ment of numerous work-producing devices or heat forces on the offset of the crank shaft. As such, there is engines. Among these are internal combustion engines produced a limited amount of energy at the torque such as the diesel engine or cycle, the gasoline engine or producing position(s) of the crank angle. For example, Otto cycle and the Wankel rotary engine as well as the maximum pressure differential may occur at or near turbines such as the steam turbine engine or the Rankine dead center of the piston’s travel with concomitant poor cycle and the gas turbine engine or Brayton cycle. The crank angle position to produce torque. Stirling engine and other cycles have also been de?ned. Other devices or methods require relatively high Many work-producing devices or engines utilize a operational temperatures. Still other methods and de working ?uid in the form of a gas. The spark-ignition vices have limited thermal ef?ciency in relation to the automotive engine is a familiar example, and the same is Carnot cycle. Other devices and methods require rela true of the diesel engine and the conventional gas tur tively high mass ?ow per unit of power produced, bine. In all of these engines there is a change in composi while others suffer from inef?cient fuel consumption tion of the working ?uid, because during combustion it and incomplete fuel combustion. Other devices and changes from air and fuel to combustion products. For this reason these engines are called internal combustion 30 methods have lower efficiencies under partial loads or engines. In contrast to this the steam power plant may at lower speeds while others suffer energy losses due to be called an external-combustion engine, because heat is condensation. Still other devices and methods are rela transferred from the products of combustion to the tively complex and hence expensive to operate. ' working ?uid. These external-combustion engines or These and other shortcomings of the prior devices, cycles undergo a variety of processes including com including internal and external combustion engines, are pression or expansion at varying conditions in order to alleviated if not eliminated by the present method and produce work. The cycles are often de?ned in terms of apparatus. these processes. For example, the working ?uid in the SUMMARY OF THE INVENTION Rankine cycle ideally undergoes the following steps: a reversible adiabatic pumping process in a pump; a con 40 There is provided an external combustion process stant-pressure transfer of heat in a boiler; a reversible and apparatus for generating power. A heated vapor is adiabatic expansion in the turbine or other prime mover generated from a working ?uid by means of an evapora such as a steam engine; and a constant-pressure transfer tor located within a high pressure zone having a high of heat in a condenser. pressure cylinder and piston operably connected to a In the Stirling cycle the heat is transferred to a work 45 working shaft. Work is imparted to the working shaft ing ?uid during a constant-volume process followed by which is rotatably coupled to the high pressure piston further heat transfer during an isothermal expansion by constantly exposing the lower face of the high pres process. Heat is then rejected during a constant volume sure piston to the vapor in the high pressure zone while process and further during an isothermal compression selectively exposing the upper face of the high pressure process. 50 piston to the vapor in the high pressure zone as the high The most ef?cient ideal process is the Carnot cycle, pressure piston approaches upper dead center in rela which de?nes the most ef?cient engine that can be tion to the working shaft. The upper face of the high operated between a high temperature and a low temper pressure piston forms a first variable volume with the ature reservoir. The Carnot cycle always involves four high pressure cylinder wall. basic steps, namely: a reversible isothermal process in 55 Concurrently with imparting work to the working which heat is transferred to or from the high tempera shaft, vapor is intermittently discharged from the ?rst ture reservoir; a reversible adiabatic process in which variable volume to a larger second variable volume the temperature of the working ?uid decreases from the formed of the lower face of a low pressure piston linked high temperature to the low temperature; a reversible directly to the high pressure piston and a low pressure isothermal process in which heat is transferred to or 60 cylinder wall. Concurrently therewith the upper face of from the low temperature reservoir; and a reversible the low pressure piston is constantly exposed to low adiabatic process in which the temperature of the work pressure vapor in a low pressure zone and the second ing ?uid increases from the low temperature to the high variable volume is intermittently exposed to the low temperature. pressure zone. The second variable volume is allowed In practice all heat engines fall short of ideal perfor 65 to increase more rapidly than the ?rst variable volume mance. This is due to a variety of factors including decreases as the high and low pressure pistons move pressure drops along piping or tubing, heat losses from bottom dead center to top dead center in relation through piping or other surfaces and deviations of the to the working shafts. 4,864,826 3 4 When the piston and cylinder assemblies are formed FIGS. 2A and 2B are longitudinal cross-sectional from a material having a low thermal conductivity, perspective views of a portion of the superheated vapor such as Torlon, the high pressure vapor in the ?rst actuated generating system shown in FIG. 1; variable volume generally undergoes a substantially FIG. 3 is a longitudinal cross-sectional view of a adiabatic isentropic expansion as the vapor is intermit valve assembly; tently discharged from the ?rst variable volume to the FIG. 4 is a transverse cross-sectional view of the second variable volume. The vapor in the high pressure valve assembly taken on line 4-4 of FIG. 3; zone impacting the lower face of the high pressure FIG. 5 is a transverse cross-sectional view of the piston performs a generally isobaric work process as the valve assembly taken on line 5-5 of FIG. 3; vapor is intermittently discharged from the ?rst vari 10 FIG. 6 is a diagram of valve timing; able volume to the second variable volume. When the FIG. 7 is a diagram of ?ow sections; high pressure piston and cylinder assembly is formed FIG. 8 is a graph of pressure vs. crank angle for from a material having a high thermal conductivity, incremental changes in pressure in high and low pres such as copper, the ?rst variable volume generally un sure cylinders; dergoes a nonadiabatic expansion as the vapor is inter FIG. 9 is a partial schematic view of a vapor power mittently discharged from the ?rst variable volume to actuated generating system according to the present the second variable volume. In this case, heat is trans disclosure; ferred to the expanding gas thus providing a greater FIGS. 10-11 are schematic representations according power output per unit of mass ?ow allowing for a to FIG. 9, but with certain elements shown in different higher horsepower to weight ratio than can be obtained 20 positions; from equivalent state-of-the-art expansion devices. FIG. 12 is a closed system energy association diagram In another embodiment there is provided a process generally depicting the operation of the embodiment for generating power including the steps of generating a shown in FIGS. 9-11; heated vapor from a working ?uid within a high pres FIG. 13 is a thermodynamic process cycle generally 25 sure zone to maintain the high pressure zone at a sub plotting temperature versus entropy for the embodi stantially constant high pressure. Work is then ?rst ment depicted in FIGS. 9-11; imparted to a working shaft coupled to a high pressure FIG. 14 is an indicator diagram for an internal com piston by placing a ?rst variable volume comprising the bustion engine; lower face of the high pressure piston and the high FIG. 15 is a schematic of an indicator diagram for the 30 embodiment disclosed in FIGS. 9-11; pressure cylinder walls in ?uid communication with the FIG. 16 is a schematic representation of another em high pressure zone while allowing discharge of working bodiment of the vapor power actuated generating sys fluid from a second variable volume formed from the tem wherein work is generated through most of a 360 upper face of the high pressure piston and the high degree cycle; pressure cylinder walls to a third variable volume FIG. 17 is a diagrammatic representation of another formed by the lower face of a low pressure piston linked detailed embodiment of a vapor power actuated gener to the high pressure piston and low pressure cylinder ating system wherein the vapor is generated in the high walls while concurrently therewith placing a fourth pressure zone; variable volume including the upper face of the low FIG. 18 is a bar graph representation of heat loss-heat pressure piston and the low pressure cylinder walls in gain of a prior art tandem compound condensing engine ?uid communication with a low pressure zone. The low and a vapor power actuated generating system of the pressure zone is maintained at a substantially constant present invention; low pressure. Thereafter, work is further imparted to FIGS. 19-21 are graphic illustrations of the work the working shaft by placing the second variable vol output of a‘prior art tandem compound condensing ume in ?uid communication with the high pressure zone 45 engine and a vapor power actuated generating system while allowing discharge of working ?uid from the ?rst of the present invention; and variable volume to the fourth variable volume and con FIG. 22 is a graphic illustration of the engine bearing currently placing the third variable volume in fluid pressures of a prior art tandem compound condensing communication with the low pressure zone. ' engine and a vapor power actuated generating system The working shaft is operably connected to a high 50 of the present invention. pressure piston by a crank mechanism rotating through 360 degrees. The high pressure piston preferably attains DETAILED DESCRIPTION a high mean effective pressure as the crank mechanism Referring ?rst to FIG. 17, there is shown a diagram approaches the optimum angle for exerting force on the matic view of one general embodiment of the present crank mechanism. 55 invention. A high pressure piston cylinder assembly A mechanism for the recycle of working ?uid may including high pressure piston 54 and high pressure also be provided. For example, where the low pressure cylinder 60 is mounted on a partition wall 214. A low zone also functions as a condenser, during the foregoing pressure piston cylinder assembly including a low pres operation an injector piston may preferably serve to sure piston 76 and low pressure cylinder 105 is mounted return condensed working ?uid coming from a conduit, on the opposite side of wall 214. The high pressure such as a suction tube, in ?uid communication with the piston is directly linked to the low pressure piston by condensed working ?uid in the low pressure zone. piston rod 57, which sealingly passes through insulated BRIEF DESCRIPTION OF THE DRAWINGS partition wall 214. High pressure reservoir zone 210 is formed from exterior insulated wall 216 and interior FIG. 1 is a diagrammatic representation of a detailed 65 partition wall 214. Low pressure reservoir or zone 212 embodiment of a superheated vapor power actuated is formed from another exterior insulated wall 218 and generating system utilizing the method disclosed herein interior insulated wall 214. The lower face of high pres and including an exhaust heat source; sure piston 54 is constantly exposed to high pressure 4,864,826 5 6 reservoir zone 210, while the upper face of low pressure certain associated heat losses which decrease system piston 76 is constantly exposed to low pressure reser thermal ef?ciency. In contrast, in the present processes voir 212. described by the above design, heat losses are reduced The high pressure cylinder 60 and the upper face of by incorporating all major system components, i.e., high pressure piston 54 form a ?rst variable volume, evaporator, expander, condenser and pump, within the while the low pressure cylinder 105 and the lower face con?nes of a single thermal boundary. By way of this of low pressure piston 76 form a second variable vol consolidation, associate line heat losses may be reduced. ume. The ?rst variable volume is selectively placed in Further, it has been shown through a computer ?uid communication with the second variable volume model that the working ?uid associated with the high by means of discharge conduit 68, discharge valve port pressure piston, cylinder and associated vapor transfer 79, and intake valve port 59. Additionally, the ?rst and lines located within the con?nes of the high pressure second variable volumes are in selective ?uid communi zone undergo a heat gain as the isolated sub-volume of cation with high pressure reservoir 210 and low pres the working ?uid contained in the high pressure cylin sure reservoir 212, respectively, by means of valve ports der undergoes an expansion process into the low pres 201 and 204. 15 sure cylinder located within the con?nes of the low The lower portion of high pressure reservoir zone pressure zone when the components are formed from a 210 is encircled by heating coil 307 such that high pres material permitting heat transfer. The low pressure sure reservoir 210 acts as an evaporator for the high piston, cylinder and associated vapor transfer lines lo pressure working ?uid being admitted through line 114. cated within the con?nes of the low pressure cylinder Water or another suitable ?uid ?owing through heating contribute to heat losses as expected in prior art expan coil 307 is heated by any of a number of low and high ders. grade heat sources as more fully described below. Referring to FIG. 18, computer modeling has shown Low pressure reservoir 212 is encircled by working that the power producing expansion process between coil 88 such that low pressure reservoir 212 acts as a the high pressure cylinder and the low pressure cylinder condenser for working ?uid being discharged through can be optimized by use of materials which are high in valve 59. Condensed working ?uid is drawn up through thermal conductivity, such as copper, in the construc conduit 100 and through intake valve 205 and discharge tion of the high pressure piston, cylinder and associated valve 206 by means of a discharge cylinder-piston as gas transfer lines located in the high pressure zone sembly formed from cylinder 89 and piston 90. Piston wherein heat gains are associated, and through the use 90 is in turn directly linked by rod 57 to low pressure of materials which are low in thermal conductivity such piston 76 and high pressure piston 54 such that the three as ceramics and carbon ?ber, in the construction of the pistons act in tandem. low pressure piston, cylinder and associated gas transfer The lower face of high pressure piston 54 is operably lines located in the low pressure zone wherein heat linked to a working shaft such as output shaft 46 by losses are associated. Further improvement can be ob means of a connecting rod 50 and yoke assembly 49. tained by providing the high pressure cylinder and Movement of the high pressure piston 54 in cylinder 60 associated gas transfer lines with ?ns to increase the rate rotates the shaft 46. of heat transfer. As indicated generally in FIG. 17, the low pressure Three different engine designs were evaluated in cylinder and piston assembly is considerably larger than FIG. 18. The ?rst was tandem compound condensing the high pressure piston and cylinder assembly. It is 40 engine such as is maufactured by the Skinner Engine de?nitely preferable that the second variable volume Company of Erie, Pennsylvania. Both the high and low have a larger volume than the ?rst variable volume. By pressure cylinders are formed of Torlon, a poly (amide way of example, the low pressure cylinder diameter imide) resin such as is manufactured by the Amoco should preferably be at least twice the diameter of the Chemicals Company. The second engine was of a de high pressure cylinder diameter. Sometimes maybe 45 sign such as illustrated in FIG. 17 in which both the three or more times the diameter, though it may be high and low pressure cylinders were formed of Torlon. bene?cial to add a second low pressure piston and cylin The third engine was of a design such as is illustrated in der assembly rather than further expand the diameter of FIG. 17 with the high pressure cylinder being formed of one low pressure cylinder. copper and the low pressure cylinder being formed The embodiment illustrated in FIG. 17 may be used 50 from Torlon. All engines were evaluated as operating advantageously with a low grade heat source, such as under identical conditions of working ?uid, speed, con waste heat. For example, systems designed for the in struction and thicknesses. dustrial cogeneration market could make use of waste The engines were operated between a high tempera heat from industrial facilities which is transferred by ture of 200° F. and a low temperature of 50° F. The high means of water ?owing through a heat absorption coil pressure was 410 psi and the low pressure was 100 psi. and then into a heating coil located in a high pressure The diameter of the high pressure cylinder was 2.5 zone functioning as an evaporator. The system’s work inches and the diameter of the low pressure cylinder ing ?uid such as Freon 22 would absorb heat from the was 5.5 inches. The engines were operated at 450 rpm. heating coil and undergo a phase change to form a As a result of the materials used in the construction of saturated or superheated vapor for use in the system. 60 various components referred to in the above embodied The foregoing design can provide an advantage in description which increases the levels of heat energy that it has been shown through computer modeling to associated with the expansion of high pressure working have a higher system thermal ef?ciency through the vapor from the high pressure cylinder into the low reduction of system heat losses associated with prior art pressure cylinder, the end of the expansion stroke and technologies. For example, as would be known to one 65 the volume swept out by the low pressure piston work skilled in the art having the bene?t of this disclosure, the ing within the low pressure cylinder is of a higher ?nal prior art technology of external combustion closed pressure differential than would be found in prior art cycle methods of generating power from a vapor have tandem compound condensing engines operating off the 4,864,826 7 8 same heat source by means of the same working ?uid volumes are in selective ?uid communication with low and mass ?ow per cycle. Because of the higher pressure pressure reservoir 210 and high pressure reservoir 212, differential at the end of the expansion stroke, optimiza respectively, by means of intake valve 201 and dis tion of the power stroke can be achieved through in charge valve 204. creasing the diameter of the low pressure cylinder and Low pressure reservoir 212 is encircled by working piston thus increasing the swept volume of the low coil 88 such that low pressure reservoir 212 acts as a pressure cylinder and correspondingly increasing the condenser for working ?uid being dicharged through size of the largest piston which results in higher levels discharge valve 204. Condensed working ?uid is drawn of rotational energy produced with associated lower up through conduit 100 and through intake valve 205 pressure differential at the end point of the expansion and discharge valve 206 by means of a discharge cylin stroke. der-piston assembly formed from cylinder 89 and piston The present invention also provides an advantage in 90. Piston 90 is in turn directly linked by rod 57 to low that it produces work in two cylinders from a single pressure piston 76 and high pressure piston 54, such that volume of working ?uid as the two pistons go through the three pistons act in tandem. the same 180° working cycle. Prior art systems such as The lower face of high pressure piston 54 is operably a tandem compound condensing engine also make use linked to a working shaft such as output shaft 46 by of a single mass to supply two cylinders, but only as the means of a connecting rod 50 and yoke assembly 49. As pistons in their respective cylinders go through differ indicated in FIGS. 9-11, movement of the high pressure ent 180° working cycles. piston 54 from left to right (as shown in the drawings) As illustrated in FIGS. 19-21 which compare the 20 and back rotates the shaft 46. work output of a prior art tandem compound condens As indicated generally in FIGS. 9-11, the low pres ing engine and a vapor power actuated generating sys sure cylinder and piston assembly is considerably larger tem of the present invention such as is illustrated in than the high pressure piston and cylinder assembly. It FIG. 17, a better mechanical ef?ciency or a better use of is de?nitely preferable that the second variable volume available forces is achieved by the present invention. 25 have a larger volume than the ?rst variable volume. By FIG. 22 illustrates the engine bearing pressures of a way of example, the low pressure cylinder diameter prior art tandem compound condensing engine and a should preferably be at least twice the diameter of the vapor power actuated generating system of the present high pressure cylinder diameter. It sometimes may be invention such as is illustrated in FIG. 17. A computer three or more times the diameter, though it may be analysis has shown that the present invention has a 30 beneficial to add a second low pressure piston and cylin~ signi?cantly lower engine bearing pressure than the der assembly rather than further expand the diameter of prior art tandem compound engine. The reduction of one low pressure cylinder. bearing pressure effectively reduces the work loss due In operation, high pressure piston 54 and low pres to friction thus increasing mechanical efficiency and sure piston 76 begin operation at 0 degrees when the facilitates a reduction in the reciprocating mass of the high and low pressure pistons are inside dead center in engine parts. Additionally, a decrease in the bearing relation to the working shaft 46 as shown in FIG. 9. At pressures decreases wear on the moving parts thus mini this juncture discharge valve 202 and intake valve 203 mizing repair and maintenance. are closed, while intake valve 201 is open to allow high Referring next to FIGS. 9-11, there is shown a sche pressure vapor to enter the ?rst variable volume. Once matic view of another general embodiment of the pres 40 high pressure working ?uid has entered the ?rst vari ent invention. A high pressure piston cylinder assembly able volume then intake valve 201 is closed and dis including high pressure piston 54 and high pressure charge valve 202 and intake valve 203 are opened, thus cylinder 60 is mounted on partition wall 214. A low placing the ?rst and second variable volumes in ?uid pressure piston cylinder assembly including a low pres communication through discharge conduit 68. As the sure piston 76 and low pressure cylinder 105 is mounted upper face of low pressure piston 76 is exposed to the on the opposite side of wall 214. The high and low low pressure working ?uid in low pressure reservoir pressure piston cylinder assemblies are placed in inter 212, while the lower face of piston 76 is exposed to a mittent selective ?uid communication by discharge relatively high pressure due to the opening of discharge conduit 68 and discharge valve 202 and intake valve valve 202 and intake valve 203 and the closing of intake 203. The high pressure piston is directly linked to the valve 201, the change in pressure or pressure differen low pressure piston by piston rod 57, which sealingly tial across the two faces of piston 76 drives the low passes through insulated partition wall 214. High pres pressure piston 76 away from inside dead center, thus sure reservoir or zone 210 is formed from exterior insu also forcing high pressure piston 54 away from inside lated wall 216 and interior partition wall 214. Low dead center. The movement of high pressure piston 54 pressure reservoir or zone 212 is formed from another and low pressure piston 76 away from inside dead cen~ exterior insulated wall 218 and interior insulated wall ter, as shown in FIG. 10, represents the power stroke. 214. The lower face of high pressure piston 54 is con At this point in time exhaust valve 204 is closed. stantly exposed to high pressure reservoir zone 210, As the working ?uid decreasing in pressure enters the while the upper face of low pressure piston 76 is con second variable volume by way of discharge conduit 68, stantly exposed to low pressure reservoir 212. the high pressure working ?uid in the high pressure The high pressure cylinder 60 and the upper face of reservoir 210 acts on the lower face of high pressure high pressure piston 54 form a first variable volume, piston 54 and serves to also drive high pressure piston while the low pressure cylinder 105 and the lower face 54 away from inside dead center, thus contributing to of low pressure piston 76 form a second variable vol the power stroke. At this point in time intake valve 201 ume. The ?rst variable volume is selectively in fluid 65 is closed. communication with the second variable volume by As shown in FIG. 11, the high pressure piston 54 and means of discharge conduit 68, discharge valve 202, and the low pressure piston 76 subsequently approach 180 intake valve 203. Similarly, the ?rst and second variable degrees or outside dead center. Exhaust valve 202 and 4,864,826 10 intake valve 203 are closed, thus cutting off discharge In the injector pump 320 there occurs an isentropic conduit 68, while intake valve 201 and discharge valve compression of liquid. This is shown in FIG. 13 from 204 are opened, thus bringing the ?rst and second vari points 401 to 402. This is followed by a constant pres able volumes into ?uid communication with the high sure or isobaric heat addition in the expansion tank with and low pressure reservoirs 210 and 212, respectively. 5 the superheat coil 324 and essentially occurs between High pressure piston 54 and low pressure piston 76 then points 402 and 403 on the entropy temperature diagram. travel from outside dead center back to inside > dead Thereafter between points 403 and 404 there is an isen center (or from 180 degrees to 360 degrees), due to the tropic expansion of the vaporized working ?uid in the momentum of an opposing cylinder bank connected high pressure cylinder 326 allowing an isobaric work through connecting rod 50 or another connecting rod 10 process to be produced by the piston contained in cylin thus preparing for another power stroke. der 326. There also occurs nearly simultaneously at this A mechanism for the recycle of working ?uid is also point a rapid isentropic compression followed by an provided. For example, during a foregoing operation an isentropic expansion of vapor in the low pressure cylin injector piston 90 may preferably serve to return con der 328 as shown by lines 404 to 403 prime (403’) to 404 densed working ?uid coming from a conduit, such as a prime (404’). These steps are followed by a constant suction tube 100, in ?uid communication with the con pressure or isobaric heat rejection from steps 404 prime densed working ?uid in the low pressure reservoir 212. (404’) through 404 to 401 occurring in condenser 330. As the high pressure and low pressure pistons 54 and 76 An indicator diagram may serve to further describe move from inside dead center to outside dead center or the process. Referring to FIG. 14 there is shown a sche from 0 to 180 degrees, the condensed ?uid is pumped matic of an indicator diagram with pressure graphed through discharge valve 206 for recycle and use in the against stroke position for an internal combustion en system. As the high and low pressure pistons 54 and 76 gine. During the suction phase of the internal combus move from outside dead center to inside dead center or tion cycle an inlet valve is open and a gas mixture ?lls from 180 to 360 degrees, condensed ?uid is drawn into a cylinder volume as the piston moves to the bottom of the volume formed by the upper face of injector piston 25 dead center. The gas volume is now at a maximum and 90 and the injector piston walls or sleeve 89. This con the pressure remains close to ambient pressure as indi densed working ?uid is then discharged on the next cated at point 501. The inlet valve then closes and the compression stroke moves the piston to top dead center, power stroke as the pistons move from inside dead the gas volume has decreased and the pressure in center to outside dead center or from O to 180 degrees. creased such that we are now at point 502 on the indica The foregoing embodiment depicted in FIGS. 9-11 tor diagram, FIG. 14. The area enclosed by the horizon may be used advantageously with a low-grade heat tal stroke-axis and the vertical lines from the axis to source, such as waste heat. For example, systems de points 501 and 502 is a measure of the compression signed for the industrial cogeneration market could work required to get to point 502. At this point the make use of waste heat from industrial facilities which is mixture is ignited which results in heat energy released transferred by means of water ?owing through a heat to the gas mixture, which is sufficiently rapid that the absorption loop and then into a heating coil located in a volume remains practically unchanged while the pres high pressure saturated vapor generating cell such as a sure increases thus bringing the process to point 503. boiler. The heating coil could be submersed in a liquid The piston is now forced down to bottom dead center reservoir of the system's working ?uid, such as a refrig and the pressure drops as the volume increases thus erant. At this point, the liquid working ?uid, such as moving the process to point 504 on the indicator dia Freon 22 (R-22), absorbs heat from the heating coil and gram, FIG. 14. The area enclosed between the curve undergoes a phase change to a saturated vapor. The 503-504 and the horizontal stroke-axis is a measure of saturated vapor then ?ows to an expansion tank with a the work produced during the expansion stroke and the super heated coil, which adds heat isobarically, gener 45 net area inside lines 501-504 is a measure of the net ally a superheated vapor of the working ?uid. The work produced during the cycle. The mean effective superheated vapor could then enter the high pressure pressure is de?ned as the area enclosed by the contour reservoir 210 for use in the system as already discussed. of lines 501-504 divided by the stroke or swept volume. Although not wishing to be held to any particular Referring now to FIG. 15, there is shown a general theory, the process disclosed herein may be viewed 50 schematic of an indicator diagram with pressure thermodynamically in conjunction with FIG. 12 and a graphed against stroke for both the high and low pres temperature entropy diagram shown schematically in sure cylinders, respectively, of the foregoing embodi FIG. 13. Referring generally to FIG. 12, and by anal ment. Just prior to the high pressure piston beginning its ogy to FIGS. 9-11, an injector pump 320 is in ?uid power stroke the pressure is at its peak in the high pres communication with a boiler or pressure cell 322 which 55 sure cylinder. This puts the process at point 601 in the receives waste heat as indicated at 310 to heat working high pressure cylinder. Concurrently, in the low pres ?uid. Working ?uid heated in boiler‘322 then passes via sure piston just prior to the beginning its power stroke line 303 to expansion tank 324 where it comes into ther the pressure is at its minimum in the low pressure cylin mal contact with a direct heat such as from natural gas der thus putting the process at point 604 in the low as indicated at 312 to form a superheated vapor. The 60 pressure cylinder. Immediately upon the opening of the superheated vapor then passes via line 304 to high pres valves allowing the volume of high pressure ?uid con sure cylinder-piston assembly 326 and then via line 305 tained in the high pressure cylinder to communicate to low pressure cylinder-piston assembly 328 to pro with the volume of low pressure ?uid contained in the duce work as indicated by lines 314 and 318. The spent low pressure cylinder, the process in the high pressure working ?uid then passes via line 306 to be condensed 65 cylinder moves to point 602 and the process in the low in condenser 330 by giving up heat as indicated by line pressure cylinder due to compression intake moves 316. The condensed working ?uid‘is then recycled via from point 605 to 606. As the direction of motion to line 301 to injector pump 320. outside dead center continues a drop in the high pres