US2286316A

US2286316A - Air conditioning

Info

Publication number: US2286316A
Application number: US150550A
Authority: US
Inventors: Sneok Edwin
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1937-06-26
Filing date: 1937-06-26
Publication date: 1942-06-16
Anticipated expiration: 1959-06-16

Description

June 16, 1942; E. SNOOK AIR CONDITIONING Filed June 26, 1957 CONDENSER;

MAR/Ko e Win flnook Patented June 1c, 1942 I Edwin sn hum of Delaware Application June as, 1931, 150,550 I I 2: Claims. (Gl tz-,4)

Juncoup 'i'roimwc. A

LAmarlllmTcx' assignorto Minne I I .apolis-Honcywell ompa'ny',"a' eorpo invention relates in general to air conditioning systems. 1

The primary objectof my invention is toprovide a novel airconditioning system which is low in first cost and which is" dependable and highly economical in-operation.

More specifically, it is anobiectyof myinvention to provideanautomatically controlled air conditioning system of the type utilizing a com- I pression refrigeration system in which the output of the compressor is'gra'duatingly varied in .trol, arrangementfis provided which will maintain the compressor output at the proper-yalue to carry whatever. cooling loadis imposed up n the compressor.,- Hence, as many cooling coils as desirable may be connected toa-singlecompressor,. and ,the, compressor operation will autoaccordance with the cooling or. conditioning load on the system in such manner that refrigerating effect produced just balances the prevailing re.- quirements for refrigeration. Y

In accordance with my invention, these results are achieved ,byutilizing an internal combustion engine for driving the compressor. This type of prime mover in its present state of development is not only very dependable and economical in operation, but also is highly flexible in output as its speed may easily be varied over a wide range without serious reduction in eiliciency. My invention contemplates utilizing this variable speed characteristic of an internal. combustion engine for providing a highly flexible air conditioning system which continuously provides just the rematically .vary to actuate whatever coolingv coils arein operation. I H v l A. further object of my; invention, therefore, is to provide a novel control system for a refrigeration system having-a plurality of coolin coils, the control system graduatingly .controlquired amount of air conditioning to maintain space conditions within proper values, and which rbadily adapts itself to any change in the conditioning load.

In accordance with my invention, I utilize a direct expansion type of cooling coil for cooling the air being conditioned, and control the throttle valve or other speed controlling device for the internal combustion engine in accordance with changes in pressure of refrigerant within the cooling coil By this arrangement, thespeed of the engine is continuously modulated in a manner to just carry the cooling load upon the cooling coil. WhileI prefer to modulate the engine speed in accordance with changes in the condition of the refrigerant in thecooling .coil vor evaporator, my invention is not limited to this specific arrangement, but may also be applied bymodulating the engine speed in accordance with one or more conditions of the air being conditioned.

One of the objectsof my invention, therefore, is to providean air conditioning system in which the speed of the engine or the output of the compressor is modulated in accordance with changes in condition of the air being conditioned in a'manner to provide just the necessary refrigeration efiect for maintaining the condition ed forstarting under load, it is necessary that ling the compressor output in a'manner to just carry the combined cooling loads ,upon all of the cooling coils.

In utilizing an internal combustion engine for driving the compressor, provision must be made for' starting and stopping the engine. Another object of the present invention consists of the provision of the engine with automatic means for causing starting of, the engine whensthere isa demand for air conditioning and for stopping the engine whenever the demand for air conditioning disappears. 1 x v As an internal combustion engine is not adaptsuch engine be unloaded during the startingop: eration. Another object; of my invention is to provide a. novel unloading arrangement, which unloads the engine while being started and which automatically throws vthe load upon the engine afterithasstarted. U a

A further object of. myinventiomis the provision. ofan automatic device for discontinuing attempts of thecontrol apparatus to start the engine if for some reason the engine failsto start after apredetermined period of,time.

,. Another object is the provision pr automatic control means for stopping .the en ine in the event of; failure of thesystemto operate properly, 4 M

While my invention is concerned particularly with air conditioning systems employing internal combustion engines, certain novel features ,are

of broader application. Other objects and advantages of my invention will appear from the following description and the appended claims.

For a full description of my invention, reference is made to the following detailed description and to the accompanying drawing in which switch 23.

the single figure illustrates diagrammatically one form of my invention.

portions of fresh and re-circulated air passed through the conditioning chamber. Within the inlet 4 of the conditioning chamber is an air 3 filter 9 which may be of any suitable form. The air after passing through filter 9 flows downwardly through a direct expansion cooling coil 2 l3 and flows from beneath said coil over a spray pipe II and through a heating element I2 to a fan I3 which is driven by a motor I4. The air discharged from the fan I3 is conveyed by a suitable duct I5 back to the conditioned space 2. Reference character I6 indicates a by-pass damper for by-passing 'a portion of the air around the cooling coil III. This damper is nor-- mally kept closed where the dehumidifying load is relatively light. In locations where the dehumidifying load is heavy, however, this damper may be operated for increasing thedehumidifying effect of the coil I'll. Suitable automatic controls for damper I6 maybe provided if desired. The humidifying spray I I and the heating element I2 are intended for winter operation. It will be understood, however, that if desired, the heating element I2 may be used for reheating during summer operation.

Reference characters I1 and I8 indicate suitable line wires which may be, for instance, 110 volts A. C. These wires are connected to a double pole switch l9 which, in turn, is connected to line wires and 2|. The line wire 23 is connected to a wire 22 having interposed therein a manual This wire is connected to a wire 24 leading to the fan motor. Also connected to the fan motor is a wire 25, this wire being connected to a wire 26 which, in turn, connects to the line wire 2 I. When the switches l9 and 23 are closed, the fan motor I4 is energized for causing a flow of air through the conditioning chamber and to the space being conditioned; During normal operation of'the system, the switches I3 and 23 are kept closed and hence the fan motor I4 operatescontinuously.

Reference character 21 indicates a liquid refrigerant line leading to the cooling coil or evaporator I3. interposed in this conduit is a solenoid valve 23 for controlling the flow of refrigerant to said cooling coil. Reference character 29 indicates a suitable expansion valve of known form which acts to reduce the pressure of the refrigerant entering the cooling coil I 3. This expansion valve if desired may be of the thermostatic type having a control bulb 33 which is attached to the discharge or suction line 3| which conveys evaporated refrigerant from the cooling coil.

The solenoid'valve 28 is caused to open and close by means of a thermostat 32 which is located within the conditioned space 2. This thermostat maybe of any suitable form and is shown herein as comprising a circular bimetallic element 33 which carries a switch blade 34 cooperating with a contact 35. When the space temperature is below a predetermined value, the bimetallic element will cause the Switch blade 34 to be separated from contact 35. Upon an increase in temperature to a predetermined value, however, the switch arm 34 will be caused to engagecontact 35. Reference character 36 indicates a step-down transformer, the primary 31 of which is connected to the wires 22 and 26 thereby causing the transformer to be energized whenever the fan motor I4 is running. The sec ondary 33 of the transformer 36 has one terminal connected to the contact 35 by a wire 33, the other terminal of said secondary being connected to the solenoid valve 23 by a wire 40. The other 7 terminal of the solenoid valve 23 is connected to the bimetallic element of the room thermostat by a wire 4|. By this arrangement, when the space temperature is low, the switch blade 34 of the thermostat is disengaged from contact 35, this causing the solenoid valve 23 to be deenergized thereby causing said valve to remain closed for preventing flow of liquid refrigerant into the cooling coil I3. When, however, the space temperature becomes too high, the thermostat 32 will cause energization of the valve 23 thereby causing said valveto open for permitting flow of refrigerant into the cooling coil.

Reference character Ia indicates a second conditioning chamber for conditioning a space 2a. The conditioning chamber In may be of the same type as the chamber I and may be provided with a solenoid valve 23a corresponding .to the valve 28 of chamber I. The valve 23a, in turn, is controlled by means of a thermostat 32a which is responsive to the temperature within the space 2a. This thermostat may, likewise, control the solenoid valve 23a in a manner to prevent flow of refrigerant into the cooling coil when the space temperature is low and to permit a flow of refrigerant into the cooling coil when the space temperature rises to a predetermined value.

The cooling coils of the conditioning chambers I and la are actuated by a common condensing unit, this unit consisting of a compressor 45 and a condenser 46. The discharge of the compressor 45 is connected to an oil separator 41 by means of a conduit 43, the outlet of said oil separator being connected by a conduit 43 to the refrigerant inlet of the condenser 46. The refrigerant.

outlet of the condenser 46 is connected to a pipe 53 which leads to a T fitting 5| to which is attached the liquid refrigerant line 21 leading to the cooling coil I3, and'the liquid refrigerant line 21a which leads to the cooling coil located within the chamber la. The outlet or suction line 3| of the cooling coil I3 is connected to a T fitting 52 and the suction line 3Ia which leads from the cooling coil within chamber Ia is also connected to said fitting. The T fitting 52, in turn, is connected to a main suction line 53' which is connected to the suction side of the compressor 45.

, From the description thus far, it will be apparent that the compressor 45 causes chilling of the cooling coils in both chambers I and Ia and that the refrigerant flowing into each of said cooling coils is controlling by means of a thermostat responsive to the temperature of the space cooled by the respective cooling coil.

The compressor 45 is driven by means of an internal combustion engine generally indicated as 55. This internal combustion engine may be of any suitable type and is-shown herein as arranged to utilize natural gas as a fuel. vThe engine 55 is provided with a usual intake manifold 56 to which is attached a carburetor 51, this carburetor being connected to a fuel supply pipe 58 in which is interposed a suitable pressure'reducing valve 59. The carburetor'il isalso provided with an air intake pipe 60 upon L Reference character 64 indicates a power shaft which is driven: by the engine 55. Mounted upon the'shait 64 is a'pulley 65 which drives through the mediumoi belts 61 a pulley" which is mounted upon the crank shaft of the compressor 45. *By this arrangement, it'will be apparentthat the internal combustion engine I drives the compressor 45. Also mounted upon the shaft 64 is a pulley, this pulley cooperating with belts" to drive a pulley II which, in turn, drives a wate circulating pump I2. The purpose of pump 1 will become apparent as this description proceeds.

Referring again to the engine 5, this-is cooled by means of a k 13 which may be open at its upper end, tank containing coil ll through'whichcooling water may be circulated.

The water jacket outlet of the engine'is connectedto the upper end ofthe tank" by means of a conduit 15, while the water Jacket inlet of the engine is-connected to the bottom of the tank by a conduit 19. By this arrangement, the usual water circulatingpump of the engine causescirculation of water from the engine into the top of the tank and from the bottom of the tank back to the engine; It will be understood that cooling water is circulated through coil 14 thereby causing the jacketwater tolbe cooled while flowing through't'ank 13. I v

The purpose of the pump 12 which isdriven by the engine, as. previously described, is for causing circulation of cooling water through the condenser for condensing the refrigerant within said condenser. For this purpose the intake of the, pump I2 is' connected to a conduit "which may lead from any suitable source of cooling water; such for instance as a cooling tower which may be located upon the roof of the building being air conditioned. The discharge of the pump "is connected to a conduit H which leads to the cooling water inlet of the condenser 46.- The cooling-water outlet of the condenser 46 is connected to a pipell! which leads back to the cooling tower. By driving the circulating pump for the cooling water by the same prime mover 'which drives th compress'or', the supply of cooling water to' the condenser is automatically varied in accordance with the requirements for cooling water. Thus, when the compressor is operating at low speed, a relatively small amount of' cooling water is neededfor condensing the compressed refrigerant. At this time, the circulating pump will be operating also at low speed and henceonly'such relativelysmall quantity of cooling water 'will'be supplied. As

'the compressor speed increases, more cooling water is required. At this time, however, the

compressor water jacket. The outlet of the compressor water jacket connectedby a pipe 94 torthe conduit '82'.'-*Ir 1terposed"in the conduit 82 between the connections "with-"pipes "and 84 is a: spring loaded reducing valve 95. The purpose orthis valve is-to'interpose 's'ufllcient resistance to the flow of waterthrough the-conduit 82 such as will causes-flow or aportion of the water through the compressor Jacket." Located in the pipe83 is a'control valve lla'.'-' By adjusting this vvalve, the flow of cooling water through the compressor jacket may-be regulated.

In order Ito-cool the internal combustion en'- gine'55, a pipe 96 isconnected into/the water conduit II, this pipe '6 conveying cold water from the cooling tower 'totheinlet. of the cool ing coil I4 which is located within thecoolin'g tank 13 for theengine 55. The outlet of" cooling coil 14 is connected by a pipe 81 to'the conduit 92 Due to the resistance oifered by the reducing valve 95, it will be apparent that water will be forced from the pipe 9| through the cooling coil II to the pipe 82. Interposed in the conduit 98 is a" control valve u'flby which the flow of cooling water through the cooling coil 14 may be controlled. j i

Interposed between the conduits ll and 92 is a by-pass 89 having located therein a valve 90. 'Ihepurpose of this by-pass is to permit a portion of the cooling'water from the cooling tower to by-pass the condenser and the cooling through the cooling tower than flows through the condenser and cooling coil IQ, this permit ting further cooling of the cooling water by the cooling tower. The valve 9ll'therefore provides a regulating means for controlling the'temperature of the water leaving the cooling tower.

While I have shown the cooling tank 13 and coil I4 for indirectly cooling the engine by the condensercooling water, it will be apparent that if desired, the condenser cooling water may be passed directly through the engine water jacket. In localities where the water is-impure, however, the arrangement which I have disclosed is preferable. 1

My invention contemplates controlling the speed of the engine graduating'lyin accordance with the refrigeration load -upon the system.

' For this purpose, I prefer to control the throttle valve of the engine in accordance with the suction or low side pressure within therefrigeration system. In this case, this result is achieved by the use, of a suction pressure controller generally indicated as- 9! .which controls a proportionin motor 92, this proportioning motor having an operating arm 93 which isconnected by suitable linkage to the throttle valve lever94 of the carburetor 51. The proportioning motor 92 may'beof any desired type and is preferably of the typeshownand described in Patent No. 2,028,110 issued to Daniel G.Taylor on January 14,1936] This type of proportioning motor ,is-

adapted to be controlled by means of a potentiometer and causes its operating shaft to assume an angular position corresponding to the position of the potentiometer slider upon its'resistance. Motor 92 receives its source of power through wires 95 and 96 which are connected to the secondary 91 ofa step-down transformer 98.

The primary 99 of transformer 98 is connected by wireslilll and Illl to the

line wires

20 and 2|. If desired, a switch I02 may be interposed in tarts and is further arranged to maintain such wire I for deenergizing transformer 98 winter operation of the system.

The suction pressure controller 9| comprises a bellows I03, this bellows being fixedly secured at its lower end and being arranged to cooperate with the actuating arm III! of a bell-crank lever which is pivoted at I05, this bell-crank lever including a control arm I06 which cooperates with a resistance I01 to form a control potentiometer. This potentiometer is connected to the proportioning motor as indicated. The interior of the bellows I03 is'connected to the suction line 53 by a conduit I08. Upon a rise in suction pressure, the bellows I03 will expand, this causing movement of the control arm I00 to the left across control resistance I01, this, in turn, resulting in a follow-up movement by the proportioning motor92 in a direction for opening the engine throttle valve. Conversely, upon a fall in suction pressure, the bellows I03 will contract under the action of spring I09, this causing movement of the control arm I06 in the opposite direction which results in a follow-up movement by the proportioning motor 82 in a direction to close the engine throttle valve. The control arrangement just described, therefore, acts to increase the flow of fuel to the engine and hence to increase the engine speed when the suction pressure increases, and to decrease the engine speed when the suction pressure decreases. The controller BI may be so designed and adjusted as to maintain the suction pressure at such a value that the cooling coil temperature is lowered suiilciently to both cool and dehumidify the air. For instance, assuming the Freon is used as the refrigerant, the controller 9| may be arranged so that the control arm I06 .engagesthe right-hand end of resistance I01 when the suction pressure falls to 34v pounds per square inch, and enga es the opposite end of said resistance when the suction pressure rises to 36 pounds per square inch.

My invention contemplates also the provision of automatic means for starting the engine when cooling is required, and for stopping the engine when the demand for cooling disappears. My invention also contemplates the provision of safety controls for automatically placing the engine out 'of operation whenever the system fails during .to function correctly. This automatic arrangement for starting and stopping the engine will now be described in detail. I

Reference character IIO indicates a starting relay for controlling the starting motor 63. This relay may be of any suitable type but is preferably of the type shown and described in Patent No, 1,773,913 issued to L. K. Loehr et al. on August 26, 1930. This starting relay is So arranged that upon' the closing of a control circuit, a magnetic device is energized which causes pulling in of a switch in the starter,circuit. For this purpose, the relay I I0 is connected to a storaeg battery III by means of a wire II2. Another terminal of the relay is connected to the starting motor 63 by means of a wire II3. One terminal of the starting motor and the battery are each grounded and hence upon the closing of the relay switch, a circuit through the starting motor is completed. The relay H0 is also arranged to open the starting motor circuit when the engine circuit open so long as the engine is in operation as determined by operation of the generator 62. Forth'is purpose, the generator 62 is connected to a terminal of relay I I0 by a wire I I4.

For controlling the control circuit of the startvenee of a heating element I33.

ing relay IIO are provided a suction pressure controller II5, a high pressure cut-out H0, 9. motor temperature thermostat H1 and a thermal cut-out II8.

Referring to the suction pressure controller II5, this controller may be of any suitable form and is shown herein as comprising a bellows II! switch I22. The free end of the switch carrier" I2I is connected to a spring I23 which urges said carrier downwardly against the bellows H3.

When the suction pressure rises above a predetermined value, the bellows II9 will expand against the action of spring. I23, this causing tilting of the mercury switch I22 to closed position. When the suction pressure falls, however,

the bellows II9 will contract under the action of spring I23, this causing tilting of the mercury switch I 22 towards open position. The controller H5 is preferably of the type having a wide differential and for this purpose the mercury switch I22 is illustrated as being of the bent type. Assuming that Freon is used as the refrigerant, this controller may be so designed and adjusted that the mercury switch I22 is tilted to open position when the suction pressure falls to, for instance, 25 pounds per square inch and to tilt to closed position when the suction pressure rises to around 40 pounds per square inch.

Referring to the high pressure cut-out 8, this controller may be similar to the controller H5 and comprises a bellows I25 which is connected to the compressor outlet pipe 49 by a tube I20.

The bellows I25 actuates through a suitable switch carrier a mercury switch I21. This controller is provided for stopping the system in the event of failure of flow of cooling-water to the condenser and is arranged to cause opening of the mercury switch I21 whenever the pressure of the refrigerant at the compressor discharge rises above a maximum desired value, for instance, pounds per square inch (assuming that Freon is used as the refrigerant).

The engine temperature responsive thermostat II1 comprises a bellows I28 which is arranged for actuating the mercury switch I29. Bellows I28 is connected by a capillary tube I28a to a control bulb I30 which is located in the jacket discharge 15 of engine 55. The bulb, tube and bellows contain a suitable volatile fluid whereby the pressure within bellows I28 varies in accordance with changes in temperature of the engine cooling water. So long as the cooling water temperature is below a maximum, the

bellows I28 will remain contracted by a spring I3I sufliciently to hold mercury switch I23 in closed position. When, however, the engine temperature exceeds a proper operating value, for instance 175 F., the bellows I28 will expand sufficiently to tilt mercury switch I28 to open position.

The thermal cut-out II8 comprises a bimetallic element I32 which is subjected to the influ- Bimetallic element I32 carries a contact which cooperates with a contact I34 for forming a switch. When the heating element I33 is unheated, the bimetallic element I32 will assume a position in which the contacts are closed. When, however, the element I33 rises to a predetermined temperature, the bimetallic element I32 will warp towards the starting motor.

contact I34 whenever said element warps. sufficientlyto cause. disengagement of its contact from contact I34. Thus, whenever heatingelement I 33 is raised to; a predetermined tempera ture,: the bimetallic element I32 will cause opening of the contacts and the contacts will beheld open .until the, clip I35; ismanually reset.

Each of the mercury switches I22, I21 and I29 and the thermal cut-out II8 are connectedin series for controllingthe control circuit. of the starting relay H; For thisv purposaawira-IS'I is: connected to the storage battery, this wire leading through an ammeter I38 and a manual switch I39 to, the mercuryswitch I29. The mercury switch I29 is, in turn, connected to mercury switch I27 by a wire- I and said latter mercu y switch-is connected by a wire I II to the mercuri switch I22, this mercury switch, in turn; being connected by a wire I42 to contact I34 of the thermal cut-out H8. The bimetallic, element I32 of the thermal cut-out H8 is connected by a wire I33 to the control terminal I56 of the startin relay IIU. The wire Id3-is also connected to an ignition coil I by means of wire I55.

-.In normal operation of the system, the mercuryswitches I29 and I21, and the thermal relay I III will remain in circuit closing position. Therefore, when the suction pressure in conduit 53 rises sufiiciently to-cause making of mercury switch I22. the circuit from the battery through each of the' mercury switches and the thermal cuteout' will beucompleted, this causing. ener- .gization of the ignition coil I45 for the engine,

cause operation of .the starting motor for starting thewengine, andwhen the engine is started, the relay I III will automatically deenergize the underthe control ofthe'suction pressure controller 9! until such time as the suction pressure in line .53 may fall sufficiently for causing controller' ll5'to open mercury switch I22.' This will result in deenergizing the ignition coil I45, thereby stopping the engine. j

The purposeof the startingrelay .I I8 is to deenergize the control circuit for the relay III) if for some reason the engineshould fail to start within apredetermined period of time.- For this purpose, the heatingelement I33 of cut-out H8 is connected by wires I41 and llfl'to the starting motor terminal. Theheating element-I33 is, therefore, energized wheneverthe starting motor 63 is operating; If the engine starts normally,

the starting motor and heating element will be energized for only a short time, and hence the heating element will not become sufllciently heat- Themotor will then operate j ed to cause opening of the contacts. If,-'however,

starting motor and of the ignition coil. The clip I35 will then hold the contacts of the controller H8 inopen position thereby preventing closing of these contacts upon cooling of heating element I33. The control arrangement just described, therefore, actsto place the system out pf operation if the engine should fail to start.

In order to start theengine 55, it isnecessary thatthe compressorload be removedas internal combustionengines arenot adapted for starting under load. .In order to-unload the'compressor whilethe enginev being started', 1 provide an automatic clutching device whichjwill now be described Reference character I50 indicates a clut'chpperating lever. This lever is arranged to be actuated by a diaphragm motor llil, this motor including a diaphragml52 attached to (a stem I53 which, inturn, is attached to the operating lever I50. A compressionspring. I54 ,urges' the stem I53 and. the diaphragm. I52 towards the right, this causing biasing of the clutch operating lever I50 in a manner to disengage the clutch. The diaphragm I52 is located within a-suitable housing and'such housing is connected by a small tube I55 to a'fitting' I56 which, in turn, is'connectedto the intake'manifold 56 by means'of a tube 'I5I.f Also attached to the'fitting I55 a tube I58 to which is connected a solenoid valve I59. This solenoid valve is of the type which opens when' energized' and whichcloses when deenergized. One terminal of solenoid valve I59 is grounded and the other terminal thereof is connected to the starting motor terminal by means of wires I48 and I50.

that the engine'is at rest and the starting motor deenergized, the solenoid valve I59 will be deenergized thereby causing it to remainclosed. At this time, also the pressurein the intake manifold of the engine will be equal to atmospheric pressure, and this will permit the diaphragm I52 to be moved by spring I54 in a direction for disengagingthe clutch. When the starting motor is energized for-starting the engine, the solenoid valve I59 will-be caused to open. This will permit a now 'of-air through tubes I58 and I51, which" prevents any reduced pressure within the intake manifold from. affecting the diaphragm I52 Therefore, 'while the engine is being started, the, clutch will be held in disengaged position by spring" I54, and the vacuum developed within theintake 'inanifoldwill'fhave no effect. Afterthe engine-starts, however, thestarting motor is automatically deenerglzed and simultaneously, the solenoid valve I59 is deen'ergized thereby causing said valve to close." will prevent flow of "air into tubes I58 and I51 thereby causing the pressure within said'tubes and in the housing surroundingthe left side of the diaphragm to reduced? to "that prevailing within the intake manifold. This will cause the diaphragm I52 tobe urged'to' the left thereby causing rotation'of lever I50' for engaging the clutch. The automatic clutching mechanism Justdescribed, therefore, causes disengagement of the clutch when the engine is stopped and causes' engagement of said clutch when the engine has started.

My invention also includes an automatic choking arrangement for choking the engine during the starting of operation. .For this purpose,'a diaphragm motor IGI is provided. This motor is similar to but smaller than the clutch operating diaphragm motor previously described. This diaphragm motor is arranged to actuate the choke arm I62 of the carburetor. When the engine is at rest, the spring of the diaphragm motor urges said motor in a direction for rotating the choke arm I52 to choking position. After the engine is started, the vacuum developed within the intake manifold causes movement of the motor for rotating the choking arm I62 to running position. Preferably, the diaphragm motor I60 is arranged so as to cause movement of the choke to running position before the clutch operating mechanism causes engagement of the clutch. This result may be obtained by making the spring of the choke diaphragm motor lighter in relation to diaphragm size than the spring of the clutch operating diaphragm motor. Also, by the use of the restrictor i55a the exhausting of the diaphragm chamber for the clutch operating diaphragm motor may be restricted, thereby causing a lapse of time to occur before engagement of the clutch, this allowing the choke to be moved to running position before the clutch engages. This restrictor also acts to cause gradual engagement of the clutch.

Operation of operation.

If now'should the temperature in either space 2 or 2a become excessive, the thermostat in such space will cause opening of its respective refrigerant valve. This will permit flow of refrigerant into the cooling coil in which such refrigerant evaporates for causing a cooling action. Due to this evaporation of refrigerant within the cooling coil, the suction pressure will eventually increase to such a value that the suction pressure controller 5' causes closing of the starting circuit, thus energizing the ignition coil for the engine and causing operation of the starting motor. At this time, the choke will be in choking position and the clutch will be disengaged. During the operation of the starting motor, the solenoid valve I 59 will be held open, thereby preventing the slight vacuum in the engine occurring during the starting operation from releasing the choke or causing engagement of the clutch. When, however, the engine starts, the starting motor is automatically deenergized and the solenoid valve I59 allowed to close. This closing of the valve I59 permits the vacuum. within the intake manifold of the engine to affect the choke diaphragm motor for releasing the choke and opening of the throttle valve. This will cause the engine speed to be increased thereby increasing the action of the compressor for countera'cting the increase in suction pressure. Conversely, when the temperature of the air flowing across the cooling coil Ill decreases, less refrigerant will beevaporated, this causing the suction pressure to decrease which, in turn, results in reducing the speed of the engine.

ner to maintain aconstantsuction pressure and to vary the compressor speed in accordance with the cooling load.

If now should the temperature in the other space become excessive, the other solenoid valve will be opened, thuspermitting a flow of refrigerant into the other cooling coil. The evaporation of refrigerant in this second coil will cause an increased amount of evaporated ree frigerant to flow to the compressor, this'resulting Y in the suction pressure rising. In response to this rise in suction pressure of the system, the

' engine speed will increase Just sufllcientlyto be closed thereby preventing entrance of re-' 'frigerant into the cooling coils. This will premaintain the suction pressure substantially con-- vent further operation of the cooling coils thereby preventing the system from-overcooling when operating. Whenever both solenoid valves are closed, the system will automatically shut down dueto the suction pressure being pumped down sufliciently low for causing controller I I! to break the control circuit for the internal combustion engine.

' It should be' noted that during operation of the system, thespeed of the water circulating pump is varied simultaneously with change in speed of the compressor, this causing the supply of cooling water for the system to be automatically varied in accordance with the operation of the system, thereby providing just the proper quantity of cooling water for satisfying the requirements for cooling.

then for affecting the clutch diaphragm motor for gradually engaging the clutch. Engagement of the clutch will cause operation of the compressor and will also cause operation of the water circulating pump for circulating water to cool the condenser, the compressor, and the engine.

Operation of the compressor will cause the evaporated refrigerant to be withdrawn from the cooling coil and compressed, this compressed refrigerant being condensed for return to the cooling coil.

From this point, the speed of the engine will be modulated in accordance with the cooling load upon the compressor by means of the suction pressure controller 99. Thus, as the temperature of the air flowing across the cooling coil increases, an increased amount of refrigerant will be evaporated thereby causing the suction pressure of the refrigeration system to increase. In response to this increase in suction pressure, the controller 9| will cause operation of the proportioning motor 92 for increasing the From the foregoing, it will be seen that .my invention provides for automatically controlling an air conditioning system utilizing an internal combustion engine as a source of power. While my invention is more concerned with air conditiomng systems utilizing internal combustion engines, certain phases of. the invention are of broader application. Also many changes whichare within the scope of my invention will be apparent to those skilled in the art. I, therefore,-

said engine, means responsive to 'a load condition on the system for graduatingly actuating said control means in a manner to vary gradu The suction pressure controller 9|, therefore, acts in a mansaid engine, automatic switching means in said circuit for causing starting of said engine when air conditioning is required, automatic clutching mechanisminterposed'between said internal combustion engine and "said compressor, said automatic clutching mechanism comprising a device responsive to vacuum developed upon operation of said enginefor' causing engagement of said clutching mechanism, and means actuated by said control circuit for preventing operation of said vacuum responsive device until after said engine is started.

2. In an air conditioning system, in combination, an evaporator, means for causing air to be conditioned to flow in heat exchange relationship with said evaporator, a compressor connected to said evaporator, an internal combustion engine for driving said compressor, control means for graduatingly varying the output of said engine, means responsive to a load condi-' tion' on the system for graduatingly actuating said control means in a-manner to vary graduatingly the output of said engine in accordance which changes in said load condition, a control circuit for automatically starting and stopping said engine, automatic switching means in said circuit for causing starting of said enginewhen said load condition, 'controlcircrii ship with said evaporator, a compressor connected to said evaporator, an internal combustion engine for driving said compressor, control means for graduatingly varying the foutput of said envgine, means responsive to a load conditionon the system for g-raduatingly actuating' s'aid control means in a manner to vary graduatingly the output of said engine in accordance with'changes in automatically starting and stoppings w hing means .associated with an '1 means for starting said engine, means for unloading said engine, and control means'for causing operation of said means' wh'ile said.

engine is being started and for. automatically causing said unloading means to be placed out of operation after said engine has started, said control meansincluding a device controlled bysaid Y I control circuit and a device responsive to'a conditlon of the engine which varies when said engine stops and starts.

6. In an air conditioning system for a space,

I in combinatiomtcooling means for said space inair conditioning is required, and automatic clutching mechanism interposed between said internal combustion engine and said compressor, said automatic clutching mechanism comprising a device responsive to vacuum developed upon operation of said engine for causing engagement of said clutchingmechanism.

'3. In a system of theclass described, in combination, an internal combustion engine, means driven by. said internal combustionengine, a

control circuit for'starting and stopping said enmin an air conditioning system, in combina- I eluding an evaporator in heat transfer relationship with said space, a compressor connected to said evaporator, an internal combustion engine connected'to said compressor for driving theand means actuated by a predetermined low in-' take manifold pressure produced by operation of the engine for rendering said unloading means tion, anevaporaton-rmeans for causing air to be conditioned to fiow in heat exchange relaiionship with .said evaporator, a compressor connected to said evaporator, an internal-combustion-engine for driving said compressor, control means for graduatingly varying the output of said engine, means responsive to a load condition on the system for graduatihgly actuating said control means in a manner to vary graduatingly the output of. said engine in accordance with changes in said load condition, control circuit means for automatically starting and stopping said engine, switching means associated with saidcircuit means for starting said engine,- means for unloading said engine, and control means for causing operation of said unloadingvmeans while said engine is being started and for auto matically causing said unloading means tobe placed out of operation after said engine has started.

5. In an air conditioning system, in combination, an evaporator, means for causing air to be conditioned to flow in heat exchange relationactuating said speed controller in a manner to inoperative to thereby cause said engine to as-' sume its load after s a t g;

V 7. In an air conditioning system for a space, in combination, cooling means for a 81 4 including an evaporator in heat transfer relationship with said space, a compressor connected to said evaporator, an internal combustion engine connected to said compressor for driving the same, said engine having a speed controller, a starting circuit means, and an intake manifold, means including a thermostat responsive to space'tfemperature for closing 'said starting circuit meansto startsaidengine when spacetemperature'rises 'to' apredetermined value, unloading means for permitting said engine to start in an unloaded condition, means actuated by a predetermined low intake manifold pressure produced-by operation ot the engine for rendering said unloading means inoperative to thereby cause said'engin'e to assume its load after starting, and means infiuenced by'the pressure in said evaporator for increase the engine speedupon increase in said pressure while decreasing the speed upon decrease in said pressure.

, 8. In an air. conditioning assembly, a compressorhaving a discharge pipe for compressed refrigerant fluid and a suction pipe for expanded refrigerant fluid, an internal combustion engine drivinglyconnected to said compressor, an ignition circuit for said internal'combustion engine, said ignition circuit including'a switch-means responsive to a function of the operation of said compressor for controlling said switch, a valve in said discharge pipe, an eiectromagnet holding said valve in open position, said electromagnet I having an operating circuit including a thermostat, the construction being such that said valve 1 will be held in open position by saidelectromag ans 'ior net, when the circuit is completed through the thermostat, whereby when said thermostat moves to open the circuit through said electromagnet said valve will close, altering the operation of said compressor to operate said switch to open said ignition'circuit.

9. In an air conditioning system for a space, in combination, cooling means for said space including an evaporator in heat transfer relationship with said space, a compressor connected to said evaporator, an internal combustion engine for driving said compressor, an ignition circuit for said engine, a speed controller for said engine, pressure responsive means influenced by the pressure in said evaporator for positioning said controller in a manner to increase the speed of the engine upon increase in said pressure and to decrease the speed of the engineupon decrease in said pressure, valve means for controlling the flow of refrigerant into said evaporator, means responsive to'the temperature of said space for closing said valve means when the temperature falls to a predetermined value, and means influenced by the pressure in said evaporator for opening said-ignition circuit in response to decrease in pressure in said evaporator caused by closing of said valve means.

10. In an airconditioning system, in combination, a cooling coil in heat exchange relationship with the air to be conditioned, a compressor connected to said cooling coil for withdrawing evaporated refrigerant therefrom and for compressing such evaporated refrigerant, a condenser for condensing the compressed refrigerant, pumping means for supplying a cooling medium to said condenser, a variable speed prime mover connected to both said compressor and said pumping means ternal combustion engine for driving said com-- pressor, a speed controller for graduatingly varying the speed of said internal combustion engine, means influenced by a condition of the refrigerant which changes upon change in load on the evaporator for controlling said speed controller in a manner for operating the en at the proper speed for carrying the wload, ignition circuit for said engine, a starting mo for said engine, means including a thermostat responsive to the temperature-of the space for energizing said ignition circuit upon rise in space temperature to a value requiring. cooling, and means energized with said ignition circuit for energizing said starting motor for starting said engine and responding to operation of said engine'for deenerv sizing said starting motor.

12. In an air conditioning system for conditioning a space, in combination, an evaporator in heat exchange relationship with said space, a compressor connected to said evaporator for withdrawing evaporated refrigerant therefrom, an internal combustion engine for driving said compressor, a speed controller for graduatingly varying the speed of said internal combustion engine, means responsive to a first condition which is indicative of the loadon the system for controlling said speed controller in a. manner to graduatingly vary the engine speed in accordance with said load condition, an ignition circuit for the engine,

a starting motor for the engine, means including a device responsive to a condition of the air in said space which is afiected by said evaporator for energizing said ignition circuit when said condition varies to a value indicating that conditioning of the air is desirable, and meansenergized with said ignition circuit for energizing said starting motor for starting said engine and responding to operation of said engine for deenergizing said starting motor.

13. In an air conditioning'system for conditioning a space, in combination, an evaporator in heat exchange relationship with said space, a compressor connected to said evaporator for withdrawing evaporated refrigerant therefrom, an internal combustion engine for driving said compressor, a speed controller for graduatingly varying the speed of said internal combustion engine, means responsive to a first condition which is indicative of the load on the system for controlling said speed controller in a manner to graduatingly vary the engine speed in accordance with said load condition, an ignition circuit for the engine, a starting motor for said engine, unloading means for said engine, means including a device responsive to a condition of the air in said space which is affected by said evaporator for energizing said ignition circuit when said condition varies to a value indicating that conditioning of the air is desirable, and means energized with said ignition circuit for controlling said unloading means and said starting motor, said last mentioned means responding to operation of said engine for placing said starting motor and unloading means out of operation.

14. In an air conditioning system for conditioning a space, in combination, an evaporator in heat exchange relationship with said space, a compressor connected to said evaporator for withdrawing evaporated refrigerant therefrom, an internal combustion engine for driving said compressor, an ignition circuit for the engine, a starting motor for said engine, electrical means for unloading said engine when energized, means including a device responsive to a condition of the air in said space which is affected by said evaporator for energizing said ignition circuit when said condition varies to a value indicating that conditioning of the air is desirable, and means energized concurrently with said ignition circuit for energizing said unloading means and said starting motor, said last mentioned means responding to operation of said engine for deenergizing said starting .motor and unloading means to place them out of'operation.

15. In an air conditioning system for conditioning a space, in combination, an evaporator in heat exchange relationship with said space, a compressor connected to said evaporator for withdrawing evaporated refrigerant therefrom, an internal combustion engine for driving said compressor, a starting motor for said engine, loading and unloading means for said engine, said loading and unloading means including electromagnetic means and being incapable of loading the engine until a lapse of time following actuation of said electromagnetic means, switching means for controlling said starting motor and said electromagnetic means, and means responsive to engine operation for positioning said switching means in a manner to place said startpressor, a starting motor for said engine, loading and unloading means for said engine, said loading and unloading means including an electromagnetically actuated valve said valve when open causing unloading of the engine, and being incapable of causing loading of the engine until a lapse of time following closure of said valve,

means including a device responsive to the condition of theair in said space which is affected by the evaporator for starting and stopping said engine, and switching means actuated in response to engine operation for controlling-said starting motor and said electromagnetically actuated valve.

17. In an air conditioning system for conditioning a space, in combination, an evaporator in heat exchange relationship with said space, a compressor connected to said evaporator for withdrawing evaporated refrigerant therefrom, an internal combustion engine for driving said compressor, loading and unloading means for said en gine, said last recited means including an electro magnetically actuated valve arranged when open to cause unloading of the engine, said valve being incapable of causing loading of the engine until a lapse of time following closure of said valve; means including a device responsive to the condition of the air in said space which is affected by the evaporator for starting and stopping said-'engine, and switching means actuated in response to engine operation for controlling said electromagnetically actuated valve.

18. In an air conditioning system for conditioning a space, in combination, an evaporator in heat exchange relationship with said space, a compressor connected to said evaporator for withdrawing evaporated refrigerant therefrom, an internal combustion engine for driving said compressor, a control circuit for automatically starting and stopping said engine, automatic switchautomatic clutching mechanismfinterposed be-' tween said internal combustion engine and said compressor, said automatic clutching mechanism comprising a device responsive to vacuum developed upon operation of the engine for causing ill gine and to position said speed governing means in'its different positions, and means to deenergize said starter after said engine is in operation.

20. An air conditioning system for conditioning a space, comprising, in combination, a conditioning chamber, fan means for causing air to flow through said chamber to said space, means including a direct expansion cooling coil for cooling the air flowing through said chamber, a compressor connected to said direct expansion cooling coil for withdrawing evaporated refrigerant therefrom, an internal combustion engine for driving said compressor and including a fuel valve,.ignition means and starting means, electrical circuits in control of the ignition means and starting means of the engine, a switch in control of said circuits, means to render said starting means inoperative after the engine had been placed in operation and while said switch ,is closed, electrical means in control of the fuel valve of the engine energizable in a manner to position the fuel valve in at least two difierent positions whereby the speed of the engine may be varied when the engine is in operation, and an electrical controller in control of the energization of said electrical means, said switch and said electrical controller both being responsive to a single condition whichis indicative of the load on the system.

21. In a refrigeration system, in combination, an evaporator, a compressor for supplying refrigerant to said evaporator, an internal combustion engine for driving said compressor, a starting motor for theengine, unloading means for unloading the engine during starting thereof and including an electromagnetic valve, and means to energize said starting motor and valve simultaneously and to maintain said valve open until the starting motor is deenergized, the arrangement being such that the load is not placed on said engine until said valve is deenergized.

ing means in said circuit forcausing starting of the engine when air conditioning is required, and

ing the air flowing through said chamber, a compressor connected to said direct expansion cooling coil for withdrawing evaporated refrigerant therefrom, an internal combustion engine including ignition means, starting means and speed governing means for driving said compressor, electrical means energizable to start said internal combustion engine and to position the speed govmeans and a circuit for the starting means, means responsive to a load condition on the system in control of said electrical means to start the en- 22. In a refrigeration system, in combination,

an evaporator, a compressor for supplying refrigerant to said evaporator, an internal combustion engine for driving said compressor, a starting motor for the engine, unloading means for unloading the engine during starting thereof and including an electromagnetic valve, means to energize said starting motor and valvesimultaneously and to maintain said valve open until the starting motor is deenergized, the arrangement being such that the load is not placed on said engine until said valve is deenergized, and means for automatically varying the speed of said engine in accordance with the load on the system while the engine is in operation.

23. In an air conditioning system for conditioning a space,-in combination, an evaporator in heat exchange relationship with said space, a compressor connected to said evaporator for withdrawing evaporated refrigerant therefrom, an internal combustion engine for driving said compressor, a starting motor for said engine, loading means for said engine, time delay means in control of said loading means, and control means responsive to engine operation for automatically rendering said starting motor inoperative and for simultaneously placing said time delay means in operation when the engine is in operation whereby the loadis applied to said eni gine only after a delayed interval following deenergization of said starting motor.

EDWIN SNOOK.