US3797249A

US3797249A - Automatic vapor engine start-up

Info

Publication number: US3797249A
Application number: US00215898A
Authority: US
Inventors: C Pezaris; W Tegan; P Trame
Original assignee: Thermo Electron Corp
Current assignee: Thermo Fisher Scientific Inc
Priority date: 1972-01-06
Filing date: 1972-01-06
Publication date: 1974-03-19
Anticipated expiration: 1991-03-19
Also published as: CA966675A; IT973268B; FR2167749A5; JPS4878302A; DE2263793A1

Abstract

An automatic start-up system for a Rankine cycle engine provides start-up from a single actuation; for example, the closing of a switch. The start-up system initiates operation of a vapor generator for vaporizing working fluid which is admitted to an expander to produce work and a pumping system which supplies working fluid in the liquid state to the vapor generator. When the vaporized working fluid from the vapor generator begins to operate the expander at a predetermined running speed, the startup system is deenergized to terminate start-up operation. The engine then continues in a running mode. The engine may have a valve between the vapor generator and the expander for controlling admission of vaporized working fluid to the expander. When such a valve is present, a control means responsive to an appropriate engine operating condition is provided for establishing the proper valve setting.

Description

United States Patent Pezaris e t al.

AUTOMATIC VAPOR ENGINE START-UP Inventors: Constantine D. Pezaris, Nahant;

William P. Tegan, Billerica; Paul J. Tram'e, South Hamilton, all of Mass.

[73] Assignee: Thermo Electron Corporation,

Waltham, Mass. I

[22] Filed: Jan. 6, 1972 [21] Appl. No.: 215,898

52 US. Cl. 60/106, 122/406 [51] Int. Cl. F23n 1/10 [58] Field of Search 60/105, 106,107, 6, 73; 122/33, 406 ST [56] I References Cited UNITED STATES PATENTS 702,491 6/1902 Serpollet 60/106 3.264.826 8/1966 Kane et a1... 60/73 3271960 9/1966 Brunner... 60/73 1,551,438 8/1925 Staley 60/105 1.664.329 3/1928 Staley 60/105 3.172.266 3/1965 Strohmeyer 60/105 3.477.412 11/1969 Kitrilakis 122/33 Primary Examiner-Edgar W. Geoghegan Assistant Examiner1-I. Burks, Sr. Attorney, Agent, or Firm-James L. Neal 57 ABSTRACT An automatic start-up system for a Rankine cycle engine provides start-up from a single actuation; for example, the closing of a switch. The start-up system initiates operation of a vapor generator for vaporizing working fluid which is admitted to an expander to pro duce work and a pumping system which supplies working fluid in the liquid state to the vapor generator. When the vaporized working fluid from the vapor generator begins to operate the expander at a predetermined running speed, the start-up system is deenergized to terminate start-up operation. The engine then continues in a running mode. The engine may have a valve between the vapor generator and the expander for controlling admission of vaporized working fluid to the expander. When such a valve is present, a control means responsive to an appropriate engine operating condition is provided for establishing the proper valve setting.

23 Claims, 6 Drawing Figures 177 156 PS VALVE CONTROL SECTION 194 190 I 184 186 PULSE 192 f I BATTERY I S M GENERAToRI I 163 s I STEPPING ooMPAR ToR I MoToR CIRCUIT MEANS I 102 108 LEVEL J l DETECTOR I I I I 196 1E2 ----v-- 193I BURNER 1 II I CONTROL V I v I SEPARATOR I I MEANS I VAPOR 164 GENERATOR I 200 I I I 136 I I COMBUSTION I I #114 I I I BLOWER BuRNERI AND IGNITION I I 104 121 166 I 118 ATQMIZATION I I n I'" COMPRESSOR I 3 REGENERATOn EXPANDER I :170 I I v 122 I FUEL I /I I PUMPI VALVE l 124T 128 129 I I A71 132 I I coNoENsER RECEIVER 1as L :35: I I A.

NEG I PRESSURE VOLTAGE CONTROL I BOOST J I VAPOR GENERATOR SOURCE I VALVE PUMP [BATTERY l STARTING SECTION I I 138 PUMP 176 INHIBIT STARTING sEcT1oN PATENIEUHARIS I974 3797249 sum 2 OF 4 VAPOR TO ENGINE WATER Iso 152 146 WORKING LIQUID TO BOILER PATENTEDHAR 19 I974 SHEET 3 BF 4 Fig. 3.

r Fig: 4.

AUTOMATIC VAPOR ENGINE START-UP BACKGROUND OF THE INVENTION Vapor engines of the Rankine cycle type provide a desirable power source for numerous reasons, including the relatively low level of pollutant production resulting from their use. However, difficulty has been experienced in providing a start-up system which is dependable, easy'to operate and economically feasible.

SUMMARY OF THE INVENTION The engine start-up system of this invention is capable of initiating operation of the engine by a single actuation. When actuation occurs, operation according to a start-up mode begins and produces various starting events in the proper manner and the proper sequence. Essentially, the start-up system ignites a burner for a vapor generator while supplying working fluid in the liquid state to the vapor generator. In the vapor generator, the working fluid is evaporated, brought to an appropriately elevated temperature and is usually superheated. Vapor from the vapor generator is admitted to an expander to produce work from expansion of the vaporized working fluid. When expander. operation reaches a predetermined operating speed, operation according to the start-up mode is terminated and operation continues in the running mode.

Vapor generator and pumping system operation may be initiated simultaneously or in sequence, according to the dictates of the particular engine under consideration. It is often preferable to first initiate operation of the vapor generator so that it is brought to a predetermined temperature level before an appreciable amount of working fluid in the liquid state is supplied thereto.

Vaporized working fluid from the vapor generator may be fed directly to the expander or a valve may control its admission. In systems incorporating such a valve, the valve would typically be closed at start-up and remain closed until predetermined temperature and pressure conditions exist in the engine. The valve would then be opened to admit vaporized working fluid to the expander. Such operation of the valve to control admission of working fluid to the expander assures that the working fluidwhich reaches the expander will be at or near the optimum temperature and pressure to thereby facilitate a more positive start for the engine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a preferred embodiment of the invention;

FIG. 2 illustrates an example of a vapor generator usable with the engine of FIG. 1;

FIG. 3 is a schematic view showing an alternate embodiment of the invention;

FIG. 4 illustrates a typical control for the apparatus of FIG. 3; I

FIG. 5 is a schematic illustration of another embodiment of the invention; and

FIG. 6 shows a typical control for the apparatus of FIG. 5.

DETAILED DESCRIPTION OF THE DRAWINGS Reference will now be made to FIG. 1. The Rankine cycle engine 100 incorporates a vapor generator 102 and burner means 104. An outlet line 106 extends from the vapor generator to an oil separator 108. From the oil separator, a line 1 10 extends to a throttle valve 1 12 and an oil drain 114 extends to the oil storage zone of an expander 116. The throttle valve 112 controls admission of vaporized working fluid to the expander 116. The expander expands the vaporized working fluid to produce work. In this embodiment, the expander turns a driveshaft 119 and an alternator 117 to produce alternating current. Working fluid from the expander is discharged through a line 118 to the vapor side of a regenerative heat exchanger 120. The vapor then passes from the regenerative heat exchanger through a line 122, to a working fluid condensing means 124. The working fluid passing from the vapor generator to the condenser is in the vapor phase. Consequently, this portion of the engine is referred to as the vapor side. correspondingly, in the portion of the cycle from the condenser back to the vapor generator, the working fluid is in its liquid phase and this portion of the engine is referred to as the liquid side. Liquified working fluid passes from the condenser 124 through the line 128 to a receiver, or reservoir, 130. A centrifugal boost pump 131 communicates with the outlet of the receiver and is capable of supplying working fluid from the receiver to a feed pump 132. The feed pump delivers working fluid, through the line 134, to the liquid side of the regenerative heat exchanger 120. The condensed working fluid is heated in the regenerative heat exchanger and delivered through a line 136 to the inlet of the vapor generator 102. A relief line 138 joins

lines

128 and 134. A pressure control valve 140 in the relief line permits a flow of working fluid back to the receiver 130 if the output of the feed pump 132 is in excess of that required for operation of the engine.

This engine may employ any convenient form of vapor generator. One which has been found to provide good results is that described in US. Pat. No. 3,477,412 which issued on Nov. 1 l, 1969 to Soti ris Kitrilakis and is assigned to the assignee of the present ap plication. A brief description of this vapor generator will be; given in connection with FIG. 2. a more complete explanationmay be obtained by reference to the above designated patent.

There is provided within a housing 142 a burner 144 forming part of the burner means 104 and a coiled heat exchange tube means 146. The heat exchange tube means comprises an inner tube 148 for conducting working fluid through the vapor generator and an outer tube 150 which surrounds the inner tube 148 concentrically and provides a space 152 between the tubes for containing a thermally stable buffer fluid. The outer tube 150 forms part of a closed buffer fluid system which includes an expansion chamber 154. The buffer fluid provides a temperature buffer between the heat source and the working fluid to avoid hot spots within the vapor generatorv along the tube 148. From the expansion chamber 154, there is provided a pressure sensitive device 156 which is capable of providing a signal 158 proportional to buffer fluid pressure. Buffer fluid pressure will, in turn, be a function of working fluid temperature. The signal 158 may be fluid, electrical, or of any suitable type. The subsequent discussion of the signal presupposes that it is electrical.

The start-up system for the vapor engine set forth above will now be described. For convenience of discussion, the start-up system may be regarded as having three basic sections. These are a vapor generator starting section 171, a pump starting section 173, and a valve control section 175.

The vapor generating starting section 171 includes a burner control means 162, a combustion blower and ignition means 164, an atomization compressor 166, fuel pump means 168, and fuel valve means 170.

The pump starting section 173 draws electrical energy from a battery 176 which constitutes an auxiliary power source. A current relay 180 and rectifier 178 provide a switchable electrical connection between the battery 176 and the boost pump 131 and between the battery and a set of dc windings in a manner-herafter described. The starting motor 182 turns the expander driveshaft 1 17. The starting motor 182 may be a separate component of the dc windings or the starting motor may be incorporated within the alternator 117.

The valve control section 175 comprises a stepping motor 184 and a stepping motor drive circuit 186 for controlling the position of the valve 112. The stepping motor drive circuit 186 is operated as a function of the operating speed of the expander 116. The control means 175 illustrated here by way of example is fully described and set forth in copending and coassigned U.'S. patent application Ser. No. 215,838, filed Jan. 6, 1972 in the names of Peter Teagan, Constantine Pezaris, and Paul Trame and entitled Vapor EngineSpeed Control. Briefly, the valve control means 175 utilizes the alternator 117 as a tachometer signal from the expander 116. This signal input 188 is fed to a comparator means 190 which compares it to a reference signal,-

the reference signal being related to the desired operational speed of the expander 116. The output of the comparator means 190 is fed through an adder means 192 which provides a signal input to a pulse generator 194 and a level detector 196. The outputs of the pulse generator and the level detector are fed to the stepping motor drive 186. The pulse generator determines the number of pulses and thereby the distance which the stepping motor 184 and the valve 112 will move and the level detector 196 determines the direction in which the valve element 112 will move in accordance with the polarity of the signal received from the adder 192. The throttle valve 112 is thus capable of adjustment to fully open and fully closed positions and to a full range of intermediate positions. One example of a throttle valve suitable for use with the valve control means 175 is described in a copending and coassigned US. patent application Ser. 215837 filed Jan. 6, 1962 in the name of ThomasLeFeuvre and entitled Throttle Valve.

There is provided in line 134, adjacent the outlet of the feed pump 132, a pressure switch 135 for selectively admitting a negative voltage signal 137 to the added means 192. When this signal is absent, the valve control means 175 operates as described above. When present, the signal 137 is of substantially greater magnitude than the adder input from the comparator 190 and thus operates as an inhibiting signal, overriding valve opening inputs to the pulse generator 194 and the level detector 196.

OPERATION The engine first operates according to a start-up mode and, when a predetermined running speed has been reached, operation continues according to a running mode.

The entire starting and running mode proceeds automatically from a single actuation by an operator. For example, an operator may push a button 200 to close a switch within the burner control means 162. The pressure switch provides the inhibiting signal 137 to the adder 192. The burner control means then simultaneously provides electrical energy to the fuel pump 168, fuel valve 170, atomization compressor 166, and the combustion blower and ignitor 164. The result is the energization of burner means 104 whereby the vapor generator 102 is heated to initiate production of working fluid vapor. The heat from the burner elevates the temperature of the

coils

148 and 150 and the buffer fluid within the space 152. The coils, the buffer fluid and the working fluid within the tube 150 are all quickly raised to substantially the same temperature. When the temperature in the vapor generator is elevated, the buffer fluid will experience a corresponding pressure elevation. Therefore, the pressure of the buffer fluid may be selected as a means by which the temperature of the working fluid vapor within the vapor generator is measured. Accordingly, the pressure responsive device 156 provides a signal 158 functionally related to the pressure of the buffer fluid and to the temperature of working fluid within the tube 150. This signal constitutes an input to the siliconcontrolled rectifier 178 in the pump starting section 172. For example, when the pressure of the buffer fluid reaches a predetermined level, such as 500 psi, the pressure responsive device 156 may operate to provide the input signal to the rectifier 178. The pump starting section 173 is electrically connected to the auxiliary power source 176 which initially energizes the pump means (131,132). When the rectifier 178 is turned on, current flows from the battery to the dc winding in the starting motor 182. This, in turn, begins to rotate the driveshaft 119 to advance both the expander 116 and the feed pump 132. When current flow to the start-up motor 182 reaches a predetermined level, the current sensitive relay 180 switches on and energizes the boost pump 131. The boost pump will then supply fluid under pressure from the reservoir 132 to the feed pump 132. The head supplied by the boost pump 131 to the feed pump 132 prevents cavitation of the feed pump, therefore the feed pump very quickly begins to supply working fluid in the liquid-state to the vapor generator 102 through

lines

134 and 136. Fluid entering the vapor generator 102 is vaporized and supplied to the throttle valve 112 through

lines

106 and 110. The pumping action of the boost pump 131 and the feed pump 132 continue until a predetermined pressure, for example 400 psi, is built up in the line 134. When this occurs, the pressure sensing device 135 terminates the inhibiting signal 137 to the adder 192. This permits the valve control means to operate the valve 112 according to the output of the alternator 117. Since the alternator is either not operating at all or being driven at a very low level by the starting motor 182, the valve control section 175 opens the valve 112 to substantially the fully open position. v

The opening of the valve 112 admits vaporized working fluid into the expander 116. The vaporized working fluid expands and produces work which is manifested as a rotational output of the driveshaft 119 and a corresponding electrical output of the alternator 117. The

vapor input to the expander 116 very quickly raises it to the desired operating speed, for example 1800 rpm, which is above the speed at which the starting motor 182 has been turning the driveshaft 119. As the expander 116 gains speed, the current flow to the dc winding of the start-up motor begins to decrease. When the current drops below a present level, the current sensitive relay will open and deenergize the centrifugal boost pump 131, which then acts only as a conduit within the system. As the expander 116 continues to pick up speed, the current flow to the silicon controlled rectifier 178 will pass a null point and then the dc windings will begin to act as a generator and produce a current flow back to the battery 176, thus tending to charge the battery. When the current flow at the start-up motor reaches zero or reverses, the rectifier 178 turns off and is non-conductive. The current output of the start-up motor is permitted to flow to the battery 176 through the diode 179. Operation according to the start-up mode is thus terminated. It can be seen from the foregoing description, that the

elements

178 and 180 operate as independently actuable switches and constitute an automatic coupling means which is operable to initiate and terminate the start-up mode of operation.

The engine 100 continues operating in a selfsustaining manner according to the running mode. According to the running mode, the vapor generator 102 supplies vaporized working fluid along the line 106, through the separator 108, and along the lines 110 to the valve 112. The valve 112 admits working fluid to the expander. Expansion of the working fluid results in the output for rotating the shaft 119 to turn the alternator 117 and produce an electrical current output. Working fluid is exhausted from the expander 116 through the line 118 to be regenerative heat exchanger 120 where some of the energy stored in the vapor is transferred to working fluid in the liquid state passing through the coil 121. From the regenerator 120, working fluid passes along the line 122 to the condenser 124 where it is liquified and admitted to the receiver 130. The feed pump 132 operates directly from the expander. It drives the liquid working fluid through the heat exchange coil 121 of the regenerator 120 and line 136 to the vapor generator 102. The pressure control valve 140 permits working fluid to return from the line 134 to the reservoir 130, if the feed pump 132 is providing an output in excess of that required by the engine.

The valve control means 175, valve 112, expander 116, and alternator 117 operate essentially as a closed loop during the running mode to control the valve setting in accordance with the running speed of the alternator. The valve control 175 monitors the output of the alternator 117 through the continuous input 188 to the comparator means 190. The imput 188 is compared to a standard functionally related to the desired operating speed of the expander 116. The comparator means provides an input through the adder means 192 to the pulse generator 194 and level detector 196, as described above. This operates stepping motor circuit 186 and the stepping motor 184 to variable control the position of the valve 1 12 to thereby variably control admission of working fluid vapor to the expander. Further, in the running mode, the burner control means 162 may be provided with a signal, designated 163, for controlling the operation of the burner means 104 in accordance with conditions within the vapor generator.

The separator 108 removes any lubricant which has entered the working fluid stream and returns it to a lubricant isolating zone in the expander 116. The line 129 permits a controlled amount of lubricant to pass from the expander to the reservoir when the liquid level in the reservoir is low, as at start-up. A suitable lubricant system is particularly described in copending and coassigned US. patent application Ser. No. 210,749, filed Dec. 22, 1971 in the names of Walter Witzel and Edward Doyle entitled Rankine Cycle Start- Up System.

This preferred embodiment of the invention has been described in connection with an engine for operating an alternator, in which system a constant running speed is usually required. In the event of a constant running speed being required, the reference to which the comparator compares the tachometer signal from the expander is fixed. On theother hand, this system is equally usable in circumstances wherein a variable output engine is required, for example, in an automobile power plant. When a variable speed engine is desired, the reference to which the tachometer signal from the expander 116 is compared is variable. For example, it may be variable in accordance with an accelerator position.

Any suitable working fluid, buffer fluid and lubricant may be used in the above described system, so long as they are compatible with system components and each other. For example, the working fluid may be trifluoroethanol and water mixture such as Fluoronal 85 manufactured by E. I. du Pont de Nemours & Company, and the buffer fluid may be water. Other examples of working fluids are pure trifluoroethanol, thiophene, and pyridine. Other lubricants may be Sunisco 365 manufactured by Sun Oil Company, and Humble Therm 500 or Teresso 43 manufactured by Humble Oil Company.

The buffer fluid may be any suitable fluid which will not decompose at the temperature and pressures encountered.

The above description appears to be characterized by several individual power sources; the battery 176, the battery 177, the negative voltage source 133, and a current source for the comparator means 190. All of these may be obtained from a single dc power source, numerous power sources being shown in FIG. 1 mainly to simplify the drawing.

This invention contemplates that numerous changes may be made in the system described above. Accordingly, several of the preferred embodiments will now be described in connection with FIGS. 3 through 6.

Referencewill first be made to FIG. 3. The engine 10 includes a vapor generator 12 associated with a burner means 46. Extending from the vapor generator 12 is a line 16 for conducting vaporized working fluid from the vapor generator to an expander 18. The expander expands the vaporized working fluid to produce a rotary output of a shaft 20. From the expander 18, the vaporized working fluid is exhausted through a line 22 to a regenerative heat exchanger 24. From the regenerative heat exchanger, the working fluid passes through a line 26 to a condenser means 28. The pump means 30 then draws the condensed working fluid from the condenser 28, drives it through the liquid side of the regenerative heat exchanger 24 and returns it to the vapor generator 12.

A start-up means 32 comprises any conventional start-up motor, such as dc windings 34, a control means 36, the burner means 46, and a pumping means 30 which includes a feed pump 38 and a boost pump 46. The burner means 46, the dc windings 34, and the boost pump 40 are connected in electrical circuit with the control means 36 as shown in FIG. 4. The control means includes a double-pole single throw switch 50, a current sensitive relay 52, and a battery means 54. At start-up, the switch 50 is closed and energy from the battery means 54 initiates substantially simultaneous operation of the burner means 46, the starting motor means 34, and the boost pump 40. The burner means is ignited through the switch 50. The boost pump and starting motor and energized through the switch 50 and the current sensitive relay 52. The starting motor turns the expander 18 and the feed pump 38, while the boost pump 40 supplies working fluid in the liquid state from a working fluid retaining zone in the condenser means 28 to the feed pump 38. The vapor generator vaporizes the fluid and supplies it to the expander. As the vaporized working fluid enters the expander, it begins to op-' erate independently of the start-up motor. As the operational speed of the driveshaft increases, there is a corresponding current reduction in the dc windings of the start-up motor. When the current drops below a predetermined level, the current sensitive relay 52 will open the connection to the boost pump. The engine will then continue operating in therunning mode. In the running mode, the dc windings act as a generator, but the current generated is below the level required for operating the current sensitive relay 52 so the boost pump 40 is not reenergized.

FIG. 5 illustrates another embodiment of this invention. The control means is for the embodiment of FIG. 5 designated 36' and illustrated in FIG. 6. Like numerals are used to designate parts like those in FIGS. 3 and 4. The control means 36' includes the switch 50, the

battery 54, and the current sensitive relay 52. Interposed between the current sensitive relay and the switch is a silicon controlled rectifier 54 capable of receiving a signal from a temperature sensing means 56 in the vapor generator 12. In parallel with the rectifier 54 is a diode 56. To operate the start-up system, the switch means 50 is closed. First, the battery energizes the burner 46 and the burner raises the temperature of the vapor generator. When the temperature in the vapor generator has reached a predetermined level, the temperature sensing means 56 provides an electrical signal to the rectifier 54. The rectifier switches on and permits current to flow along the line 58 to the start-up motor 34. The current energizes the current sensitive relay 52 and thereby initiates operation of the boost pump 40. The system is now operating according to the start-up mode. Operation of the start-up system continues until the working fluid vapor from the vapor generator drives the expander at a speed sufficient to cause the dc winding in the start-up motor 34 to provide a current reversal of the type described above in connection with FIGS. 1 and 4. As the current flow to the dc windings drops below a certain predetermined level, the current sensitive relay 52 cuts off and deenergizes the boost pump 40. When the current actually passes the null point, the current rectifier turns off and is nonconductive in eitherdirection. As the expander 18 rises to and reaches its running speed, the dc windings of the start-up motor will act as generator and charge the battery 54. This battery charging current is below the level required to deenergize the current sensitive relay 52.

The diode 56 permits flow of current from the start-up motor to the battery.

It can be appreciated that this is essentially a twostage start-up system in the first stage of which the burner 46 is energized and in the second stage of which the start-up motor 34 and the boost pump 40 are energized. The primary advantage of the system of FIGS. 5 and 6 over that of FIGS. 3 and 4 is that working fluid in the liquid state is driven into a preheated vapor generator. Accordingly, a larger volume of working fluid may be driven through the vapor generator initially to shorten the time required for the Rankine cycle engine to reach its running mode and achieve shut-down of the start-up system.

The apparatus illustrated in FIG. 5 may, in addition, include valve means 60 for controlling admission of vaporized working fluid from the vapor generator 12 to the expander 18 and a control means 62 for the valve. The control means 62 may be responsive to temperature and pressure sensitive

signal producing device

64 and 66, respectively. The signal producing devices may be positioned at the outlet of the vapor generator. The valve means 60 may be a throttle valve for variably controlling the admission of working fluid vapor to the expander or it may be a valve of the solenoid type which is either opened or closed. Further, the valve means 60 may be expander intake valving. One example of such expander intake valving would be the intake valving associated with each cylinder of a reciprocating piston expander. The valve means 60 and its control 62 could be of the type described in connection with FIG. 1. By way of another example, the valve means 60 may remain closed during the initial operation in the startup mode and opened only when sufficient temperature and pressure conditions at the outlet of the vapor generator are obtained.

Temperature and pressure sensitive devices for use with this invention may be of any convenient type. For example, the temperature sensing devices may be a thermocouple, a bi-metallic switch, or a thermistor. Examples of suitable pressure sensing devices are a Bourdon tube, a piston and cylinder type pressure switch, or a diaphragmtype pressure sensitive device.

The present invention has been described with reference to various preferred embodiments. It should be understood, however, that modifications may be made by those skilled in the art without departing from the scope of the invention.

We claim:

1. In a closed vapor cycle engine having a vapor generator for vaporizing working fluid, an expander for receiving from said vapor generator and expanding vaporized working fluid to produce work, means for condensing expanded working fluid vapor, and means for pumping working fluid from said condensing means to said vapor generator, an automatic start-up system comprising:

a. actuator means adapted to communicate with an electrical power source means; b. electrical meansfor energizing said vapor generator in response to operation of said actuator means;

0. valve means for admitting vaporized working fluid from said vapor generator to said expander;

d. valve control means for securing said valve means in closed condition when said actuator means is first operated and for thereafter automatically opening said valve means in response to a predetermined production of working fluid vapor in said vapor generator to supply such vapor to said expander; and

e. automatic coupling means adapted to communicate with the electrical power source means for automatically coupling said pumping means and said electrical power source means when a predetermined minimum temperature is produced in said vapor generator to initiate operation of said pumping means and for automatically uncoupling said pumping means from driving relationship with the electrical power source means subsequent to the opening of said valve means. I

2. In a closed vapor cycle engine, a start-up system according to claim 1 wherein said vapor generator comprises:

a. at least one tubular heat exchange element for conducting working fluid through said vapor generator; and

b. jacket means concentrically surrounding said heat exchange element for containing a thermally stable buffer fluid wherein the pressure of said buffer fluid is functionally related to the temperature of said working fluid and wherein said automatic coupling means is responsive to the pressure of said buffer fluid for coupling said pumping means to said electrical power source means.

3. In a closed vapor cycle engine, a start-up system according to claim 1 wherein said valve control means is responsive to at least one of the temperature and pressure conditions of working fluid in said engine.

4. In a closed vapor cycle engine, a start-up system according to claim 3 wherein said valve control means is responsive to Working fluid pressure in said engine.

5. In a closed vapor cycle engine, a start-up system according to claim 4 wherein said valve control means is responsive to working fluid pressure adjacent the outlet of said pumping means.

6. In a closed vapor cycle engine, a start-up system according to claim 3 wherein said valve control means is responsive to at least one of the temperature and pressure conditions of the working fluid at the outlet of the vapor generator.

7. In a closed vapor cycle engine, an automatic startup system comprising:

a. a vapor generator for vaporizing working fluid,

having heat source means;

b. expander means in fluid communication with said vapor generator;

c. valve means for selectively prohibiting flow of working fluid from said vapor generator when closed and admitting working fluid from said vapor generator to said expander means when open.

d. means for supplying working fluid under pressure to said vapor generator;

e. first control means for activating said heat source means and initiating operation of said supplying means;

f. second control means for operating said valve means; and

g. means for prohibiting said second control means from opening said valve means subsequent to operation of said first controlmeans for activating said heat source means an operating said supplying means and thereafter as a function of predetermined conditions in said engine, automatically permitting operation of said second control means to open said valve means.

8. In a closed vapor cycle engine, an automatic startup system according to claim 7 wherein said second control means opens said valve means to admit working fluid vapor from said vapor generator to said expander when at least one of predetermined operating temperature and pressure conditions have been attained in said engine.

9. In a closed vapor cycle engine, an automatic startup system according to claim 7 wherein said supplying means comprises:

a. means for condensing working fluid vapor exhausted from said expander means;

b. pumping means for driving working fluid from said condensing means to said vapor generator; and

c. reservoir means for supplying working fluid to said pumping means to prevent cavitation of said pumping means.

10. In a closed vapor cycle engine, an automatic start-up system according to claim 9 wherein said pumping means comprises:

a. a feed pump for directing working fluid to said vapor generator; and I b. a boost pump for drawing working fluid from said reservoir means and directing it to said feed pump.

11. In a closed vapor cycle engine, an automatic start-up system according to claim 10 wherein said feed pump is driven by said expander means and said first control means comprises:

a. means for initiating operation of said boost pump;

and

b. starting motor means for substantially simultaneously advancing said expander means and thereby said feed pump.

12. In a closed vapor cycle engine, an automatic start-up system according to claim 10 wherein said control means further comprise mean responsive to a predetermined operating speed of said expander means for deenergizing said boost pump.

13. In a closed vapor cycle engine, a start-up system according to claim 7 wherein said first control means comprises:

a. first means for activating said heat source means to elevate the temperature of said vapor generator; and

b. second means for initiating operation of said supplying means as a function of vapor generator temperature. I

14. In a vapor cycle engine, a start-up system according to claim 13 wherein said second control means op erates said valve means to admit working fluid vapor to said expander means in response to a predetermined working fluid pressure.

15. In a closed vapor cycle engine according to claim 7, a start-up system wherein said vapor generator comprises:

a. a tubular working fluid container;

b. a jacket formed about said working fluid container and disposed between said working fluid container and said heat' source means;

c. a buffer fluid filling said jacket, whereby heat energy is transferred from said jacket, through said buffer fluid, tosaid working fluid container;

d. means for activating said heat source means; and

e. means for initiating operation of said supplying means as a function of buffer fluid pressure, said buffer fluid pressure being functionally related to the temperature of working fluid in said working fluid container.

16. In a vapor cycle engine, a start-up system according to claim 15 wherein said second control means operates said valve means to admit working fluid to said expander means in response to a predetermined working fluid pressure. I

17. The apparatus of claim 3 wherein said valve control means opens said valve means in response to a predetermined pressure level at the output of said pumping means.

18. In a closed vapor cycle engine, a start-up system according to claim 3 wherein said operating means is responsive to the output of said expander.

19. The apparatus according to claim 1 further comprising starting motor means energizable by said coupling means for initiating operation of said expander.

20. The apparatus of claim 19 wherein said coupling means automatically energizes said starting motor means as a function of vapor generator temperature.

21. The apparatus of claim 1 wherein said pumping means comprises a feed pump driven during a running mode by a portion of the energy released from the vastarting motor means energizable by said first switch and adapted to initiate operation of said expander and said feed pump.

23. The apparatus of claim 22 wherein said electrical power source means comprises an electrical battery and said starting motor means comprises an electrical winding linked to the output of said expander and adapted to operate said expander at a speed below normal operating speed when energized by said battery and further adapted to act as an electrical generator when said expander'output exceeds said speed below normal operating speed, further comprising means for conducting electric power generated by said starting motor means to said battery for charging said battery. =l=

Claims

1. In a closed vapor cycle engine having a vapor generator for vaporizing working fluid, an expander for receiving from said vapor generator and expanding vaporized working fluid to produce work, means for condensing expanded working fluid vapor, and means for pumping working fluid from said condensing means to said vapor generator, an automatic start-up system comprising: a. actuator means adapted to communicate with an electrical power source means; b. electrical means for energizing said vapor generator in response to operation of said actuator means; c. valve means for admitting vaporized working fluid from said vapor generator to said expander; d. valve control means for securing said valve means in closed condition when said actuator means is first operated and for thereafter automatically opening said valve means in response to a predetermined production of working fluid vapor in said vapor generator to supply such vapor to said expander; and e. automatic coupling means adapted to communicate with the electrical power source means for automatically coupling said pumping means and said electrical power source means when a predetermined minimum temperature is produced in said vapor generator to initiate operation of said pumping means and for automatically uncoupling said pumping means from driving relationship with the electrical power source means subsequent to the opening of said valve means.

2. In a closed vapor cycle engine, a start-up system according to claim 1 wherein said vapor generator comprises: a. at least one tubular heat exchange element for conducting working fluid through said vapor generator; and b. jacket means concentrically surrounding said heat exchange element for containing a thermally stable buffer fluid wherein the pressure of said buffer fluid is functionally related to the temperature of said working fluid and wherein said automatic coupling means is responsive to the pressure of said buffer fluid for coupling said pumping means to said electrical power source means.

7. In a closed vapor cycle engine, an automatic start-up system comprising: a. a vapor generator for vaporizing working fluid, having heat source means; b. expander means in fluid communication with said vapor generator; c. valve means for selectively prohibiting flow of working fluid from said vapor generator when closed and admitting working fluid from said vapor generator to said expander means when open. d. means for supplying working fluid under pressure to said vapor generator; e. first control means for activating said heat source means and initiating operation of said supplying means; f. second control means for operating said valve means; and g. means for prohibiting said second control means from opening said valve means subsequent to operation of said first control means for activating said heat source means an operating said supplying means and thereafter as a function of predetermined conditions in Said engine, automatically permitting operation of said second control means to open said valve means.

8. In a closed vapor cycle engine, an automatic start-up system according to claim 7 wherein said second control means opens said valve means to admit working fluid vapor from said vapor generator to said expander when at least one of predetermined operating temperature and pressure conditions have been attained in said engine.

9. In a closed vapor cycle engine, an automatic start-up system according to claim 7 wherein said supplying means comprises: a. means for condensing working fluid vapor exhausted from said expander means; b. pumping means for driving working fluid from said condensing means to said vapor generator; and c. reservoir means for supplying working fluid to said pumping means to prevent cavitation of said pumping means.

10. In a closed vapor cycle engine, an automatic start-up system according to claim 9 wherein said pumping means comprises: a. a feed pump for directing working fluid to said vapor generator; and b. a boost pump for drawing working fluid from said reservoir means and directing it to said feed pump.

11. In a closed vapor cycle engine, an automatic start-up system according to claim 10 wherein said feed pump is driven by said expander means and said first control means comprises: a. means for initiating operation of said boost pump; and b. starting motor means for substantially simultaneously advancing said expander means and thereby said feed pump.

13. In a closed vapor cycle engine, a start-up system according to claim 7 wherein said first control means comprises: a. first means for activating said heat source means to elevate the temperature of said vapor generator; and b. second means for initiating operation of said supplying means as a function of vapor generator temperature.

14. In a vapor cycle engine, a start-up system according to claim 13 wherein said second control means operates said valve means to admit working fluid vapor to said expander means in response to a predetermined working fluid pressure.

15. In a closed vapor cycle engine according to claim 7, a start-up system wherein said vapor generator comprises: a. a tubular working fluid container; b. a jacket formed about said working fluid container and disposed between said working fluid container and said heat source means; c. a buffer fluid filling said jacket, whereby heat energy is transferred from said jacket, through said buffer fluid, to said working fluid container; d. means for activating said heat source means; and e. means for initiating operation of said supplying means as a function of buffer fluid pressure, said buffer fluid pressure being functionally related to the temperature of working fluid in said working fluid container.

16. In a vapor cycle engine, a start-up system according to claim 15 wherein said second control means operates said valve means to admit working fluid to said expander means in response to a predetermined working fluid pressure.

21. The apparatus oF claim 1 wherein said pumping means comprises a feed pump driven during a running mode by a portion of the energy released from the vaporized working fluid for directing condensed working fluid to said vapor generator and a boost pump for drawing condensed working fluid from said condensing means during a start-up mode and directing it to said feed pump, further comprising a first switch for coupling said feed pump to said electrical power source means in response to the production of a predetermined temperature in said vapor generator and a second switch responsive to operation of said first switch for coupling said boost pump to said electrical power source means.

22. The apparatus of claim 21 further comprising starting motor means energizable by said first switch and adapted to initiate operation of said expander and said feed pump.

23. The apparatus of claim 22 wherein said electrical power source means comprises an electrical battery and said starting motor means comprises an electrical winding linked to the output of said expander and adapted to operate said expander at a speed below normal operating speed when energized by said battery and further adapted to act as an electrical generator when said expander output exceeds said speed below normal operating speed, further comprising means for conducting electric power generated by said starting motor means to said battery for charging said battery.