US2311622A - Refrigerating apparatus - Google Patents

Description

Feb. 23, 1943. D. F. ALEXANDER ETAL REFRIGERATING APPARATUS 3 Sheets-Sheet 1 Filed Aug. 3, 1940 INVENTORS. BY W 2 Manual aw? ATTORNEY.S

Feb. 23, 1943. ALEXANDER ETAL 2,311,622

REFRIGERATING APPARATUS Filed Aug. 3, 1940 3 Sheets-Sheet 2 Gil. 78

I'll ,8 20 7 v INVENTORS. @a- J ATTORNEYS Feb. 23, 1943. D, F, ALEXANDER ETAL' 2,311,622

REFRIGERATING APPARATUS Filed Aug. 3, 1940 3 Sheets-Sheet 3 Iiiihljhhllh 92 Maw WaMQ Fl 4 BY I J ,W 9 4 W 5 ATTORNEYS.

Fatented Feia. 23, 1943 UNITED STATES OFFICE REFRIGERATING APPARATUS Application August 3, 1940, Serial No. 350,706

11 Claims.

This invention relates to refrigeration and more particularly to an improved system for conditioning the air in a railway vehicle or the like.

One object of this inventionis to provide an improved air conditioning system which may be operated to efiectively condition the air in a railway vehicle under all conditions.

Another object of this invention is to provide improved protective devices for the air conditioning apparatus.

A further object of this invention is to provide an improved refrigeration and generation system in which 9. Diesel engine is used for driving the compressor and is also used for driving the main car generator.

A further object of this invention is to provide a system in which the main generator may be used as a motor for driving the compressor in case of emergency.

Still another object of this invention is to provide an improved means for reducing the amount of cycling of the refrigerating system during normal operating conditions.

Another object of this invention is to provide improved control means for regulating the conditioning apparatus.

A still further object of this invention is to provide a novel means for supplying air of uniform temperature to the engine intake manifold.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings: v

Fig. 1 is a vertical sectional view partly diagrammatic showing the mechanical arrangement of the elements in a vehicle.

Fig. 2 is a fragmentary plane view showing the arrangement of the apparatus in a vehicle.

Fig. 3 is a diagrammatic view of the heat exchange system.

' Fig. 4 shows the wiring diagram for use with the system disclosed in Fig. 1 through 3.

In Fig. 1, of the drawings, we have shown a passenger car i equipped with air conditioning apparatus, embodying features of our invention. As shownin Figs. 1 and 2, a machinery compartment I2 is provided along one side of the car Ill adjacent one end of the car. The mechanical system as shown comprises 9. Diesel engine H which drives a dynamo-electric machine I through a flexible coupling l8 and a pneumatic clutch 20. As will be explained more fully hereinafter, the clutch 20 automatically de-clutches the dynamo-electric machine 16 from the engine l4 whenever the engine l4 stops. A refrigerant compressor 22 is mounted directly above the dynamo-electric machine I6 and is driven thereby through a belt drive 24. The air intake manifold 26 of the Diesel engine is connected to a conventional air cleaner 28 which is supplied with air through the supply line 30 leading from the control panel compartment 32 in which the main controls shown in Fig. 4 are located. In a system of this type, it is necessary to use a large number of relays which tend to give off an appreciable amount of heat. It is important, therefore, to provide means for cooling the control panel compartment 32. Air from the passenger compartment 34 flows into the panel compartment 32 through an air grill 36 and picks up heat generated by the control elements. This heated air from the control panel compartment 32 i especially well suited for supplying to the Diesel engine not only because it is uniformly warm but also because it is clean.

Fuel for the Diesel engine l4 may be stored in the fuel tank 38 located in the compartment 40 directly above the machinery compartment l2. The fuel from the tank 38 is supplied to the Diesel engine through the supply line 42 in the usual manner. The flow of fuel through the line 42 is controlled by the valve 43. The engine I4 is a water cooled engine and includes the usual form of engine radiator 44 and is also provided with an auxiliary radiator 46 which may, if desired, be used for heating the air for the passenger compartment in a manner to be explained more fully hereinafter.

Outside air is circulated into the machinery compartment 12 through the inlet grill 48 arranged at the side of the car. The air entering through the grill 48 is picked up by the Diesel engine fan 50 and is discharged to the outside through the opening 52 provided in the end wall of the car. The amount of air flowing through the machinery compartment 12 is controlled by the damper 54 arranged in the opening 52. As shown in Fig. 1, the damper 54 is controlled by a bellows 56 connected to the thermostatic bulb 58 which is arranged so as to be responsive to the temperature of the air flowing through the opening 52. While we have shown the bulb it placed adjacent the opening 52, it is within the purview of this invention to place this bulb directly within the machinery compartment I2.

The refrigerating system is of the type employing a volatile refrigerant such as Freon" which is compressed by the compressor 22 and condensed within the condenser 68 which for purposes of illustration has been shown mounted beneath the car floor. The condenser may be of any conventional type and may be either air cooled, water cooled or a combination of both. In the modification shown, the condenser is air cooled and is provided with a fan 6| for flowing cooling air thereover. The condensed refrigerant is normally supplied to the main evaporator 62 mounted within the main air duct 64. The air to be conditioned is circulated through the duct 64 by means of a fan 68 driven by an electric motor 18. Recirculated air enters the duct 64 through an inlet grill 12 provided adjacent the lower part of the passenger compartment. Fresh air enters the duct 64 through the grill 14 arranged in the side wall of the car. In order to simplify this disclosure no special means has been shown for controlling the amount of fresh air introduced, however, it is within the purview of this invention to provide means for varying the ratio of fresh air to recirculated air. For purposes of disclosure, reference is hereby made to United States Patent 1,751,806, which shows one arrangement which may be used for varying the ratio of fresh air to recirculated air.

The flow of liquid refrigerant from the condenser 68 to the evaporator 62 is controlled by a conventional thermostatic expansion valve I6 provided with the usual form of thermostatic bulb 18 arranged in thermal exchange relationship with the refrigerant line 88 leading from the evaporator to the compressor, the arrangement being such that the valve 16 automatically closes whenever liquid refrigerant enters the line 88. The flow of refrigerant from the condenser 68 to the evaporator 62 is further controlled by means of a solenoid valve 82, the operation of which will be described more fully hereinafter.

Inasmuch as the Diesel. engine is normally intended to be operated continuously and inasmuch as the flow of refrigerant to the evaporator is at times prevented by the valves 16 and 82, it is desirable to provide some means for allowing a small amount of refrigerant to be circulated through the compressor 22 at all times. Accordingly, a by pass line 84 has been provided between the liquid line leading from the condenser to the valve 82 and the line 88. The flow of refrigerant through the line 84 is controlled by a conventional expansion valve 86, which is set to open whenever the suction pressure at the inlet of the compressor indicates that no appreciable amount of refrigerant is flowing through the valves 16 and 82. By virtue of this arrangement a small quantity of low pressure liquid refrigerant is allowed to enter the compressor intake with the result that the compressor is prevented from over heating. The liquid refrigerant entering the compressor tends to vaporize when coming in contact with the heated surfaces of the compressor.

As explained hereinabove, two separate heat exchange coils 44 and 46 are provided for dissipating the waste heat of the Diesel engine I4, the one coil 46 being arranged in the main air duct 64 and the other being arranged adjacent the air outlet opening 52. The flow of cooling medium through the coils 44 and 46 is controlled by the solenoid valves 88 and 88. Upon closing the valve 88 and opening the valve 88 all of the cooling liquid flows through the coil 44, whereas upon closing the valve 88 and opening the valve 88 all of the cooling fluid is caused to circulate through the heat exchanger.

In order to heat the car during the heating season we have provided a conventional steam radiator 8| which is adapted to be suppliedwith steam from the usual train steam source. The flow of steam through the radiator 8| is controlled by the valve 88 which is actuated by the thermostatic bulb 88 which may be placed in any convenient location where it will be responsive to the outside air temperature. The calibration of the valve 88 and the bulb 88 is such that the valve 88.automatically opens when the outside temperature drops below a predetermined temperature such as 50 F. The flow of steam to the radiator 4| is further controlled by the valve 81 which may be manually controlled or may be controlled by a thermostat 88 located in the lower portion of the car. Undercertain conditions the heat available in the heat exchange coil 46 is sufllcient to maintain the car temperature sufficiently high even during the winter operating conditions. However, it has been found undesirable to rely on overhead heat alone for heating purposes when the outside temperature is below 50. Consequently, it is desirable to open the valve 88 so as to make use of floor heating in addition to the overhead heating at the lower outdoor temperature, so as to eliminate cold drafts along the floor of the car. It has been found unnecessary to provide heat adjacent the floor of the car when the outside air temperatures are above 50 F.

Inasmuch as it frequently happens that neither heating or cooling is required and inasmuch as it is desirable to exhaust a portion of the car air even during the time when heating or cooling is required, we have provided means for exhausting a portion of the car air to the outside. For purposes of illustration, we have shown an exhaust fan unit 88 for this purpose. The location and number of exhaust blowers will be largely determined by the type of car and the arrangement within the car.

Referring now to Fig. 4, in which we have disclosed the electrical controls for use with the apparatus described hereinabove, it will be ob served that a main storage battery 82 is connected across the main lines 84 and 86. The arrangement being such that the main storage battery 82 is charged by the generator I6. The usual form of voltage regulator 88 is provided for regulating the voltage between the lines 86 and I88, The voltage regulator 88 is under the control of the usual form of voltage coil I82 which in normal operation is connected across the lines 86 and I88.

In order to simplify' this disclosure, many of the control switches have been shown as manually operated individual switches, whereas in actual practice these manually operated switches are controlled by cam operators which serve to close certain sets of switches simultaneously in the manner explained more fully hereinafter.

Closing of the switches I8I and I83 causes energization of the evaporator blower I8 through the switch IM and energization of the exhaust blowers 8 8 through the switch I88. Closing switch I83 also causes energization of the voltage coil I82, which in turn operates the voltage regulator 88. By closing the switches I86 and I81, the Diesel engine will be placed in operation so as to provide for operation of the generator I6. It will be noted that closing switch I86 causes energization of the delayed action relay I20 which after a predetermined time delay causes opening. of the switches I22 and I24. Closing of the switch I06 also closes the circuit through the fuel valve 43 so as to open the same and also closes the circuit to the solenoid I26, thereby closing the switch I30 and opening the switch I32 which places the current saving resistance I34 in series with the solenoid I26. Closing of the switch I30 energizes the coil I36 and the coil I38 thereby closing the main starter switch I40 which is inseries with the Diesel engine cranking motor I42 which is arranged to crank the Diesel engine in the usual well known manner. Normally the Diesel engine will start within a few seconds time. The delayed-action relay I20 serves to open the switches I 22 and I24 after a period of approximately seconds so as to prevent continued cranking of the Diesel engine and consequent damage to the cranking motor in the event that the Diesel engine does not start promptly. When the Diesel engine comes up to speed the oil pressure within the Diesel engine builds up pressure within the bel-. lows I44 and thereupon closes the switch I46 which maintains the circuit through the fuel valve 43 and the'solenoid I26 even after the switch I24 has opened. The reference character I48 designates a water thermostat which serves toopen the switch I50 in the event that the Diesel engine overheats for any reason. Energization of the solenoid coil I26, in addition to operating the switches I30 and I32, also releases the usual Diesel engine throttle I33 which is thereupon under control of the usual engine governor. Closing of the switch I01 causes current to flow through the exciter field I52 of the exciter I54 which is arranged in series with the carbon pile rheostat I56. The exciter I54 is directly driven by the Diesel engine and includes the field I52 and the armature I58. The

' charging purposes, the switch I80 closes.

armature I58 of the exciter is connected into the circuit as shown in Fig. 4 and is arranged in series with the solenoid coil I60 which when energized moves the double throw switch I6I from the full line position to the dotted line position. The solenoid I60 does not become effective until after the exciter I58 has come up to speed, that is, when the Diesel engine has approached normal operating speed. In the dotted line position the switch I6I closes the circuit from the switch I01 through the solenoid I62 provided that the high pressure cut out switch I64, which is closed at all normal conditions, is in its closed position. Encrgization of the solenoid I62 causes the switches I66 and I10 to open and the switches I61 and I68 to close. Energizing of the solenoid I62 also moves the switch I12 from its full line position to its dotted line position. Movement of the switch I12 from its full line position to the dotted line position causes the dynamo-electric machine I6 to function as a generator receiving its field energy from the exciter armature I58, Upon closing the switch I68, the solenoid I62 is maintained energized through the switch I68. Closing of the switch I61 energizes the solenoid valve 23 which is connected in the air line leading from the wind box of the engine to the pneumatic clutch 20. Energization of the valve 23 holds the valve open whereby the Diesel engine drive shaft is directly connected to the generator I6 through the flexible drive I8 and the clutch 20. Opening the switch I10 breaks the circuit from the switch I I3 to the coils. I and I33, which in turn opens the switch I to de-energize the cranking more fully hereinafter.

motor I42. Opening of the switch I66 prevents energization of the delayed-action relay coil I13. The relay I13 when energized serves to hold closed the switch I14 for purposes to be described hereinafter. With the dynamo-electric machine I6 operating as a generator, current flows through the armature of the generator through the voltage coil I16 which in turn controls the carbon pile field rheostat I56. A portion of the current also flows through the solenoid coil I18. When the flow of current through the coil I18 indicates that the generator voltage has attained a voltage suitable for battery Upon closing of the switch I80, the current coil I82 is connected in series with the generator armature, whereby the coil I82 also exerts control on the carbon pile field resistance I56, so as to limit the flow of current through the current coil I82 to a predetermined value.

As described thus far, the ventilating apparatus, the Diesel engine, the exciter and the generator are in operation and battery charging is taking place but no cooling can take place. In

order to render the cooling apparatus operable,

it is also necessary to close the switch I04. Closing the switch I04 places the thermostat I90, located in the passenger compartment of the car, in control of the cooling pilot relay coil I92.

"I'he thermostat I is adapted to open the circuit to the cooling pilot relay coil I92 whenever the temperature in the car drops below a predetermined value such as 74, for example. Energization of the cooling pilot relay coil I92 closes the switch I94 connected in circuit with the solenoid valve 82 which in turn controls the flow of refrigerant to the evaporator, as pointed out hereinabove. The switch I94 also energizes the relay coil I96 which closes the circuit through the switch I98 to the condenser fan 6 I as pointed out hereinabove. The switch I64 is always closed under normal operating conditions since this switch is not intended to operate except when the pressures within the refrigerating system exceed a predetermined range. It will also be noted that the cooling pilot switch I94 places the delayed-action relay I13 under the control of the switch I66, for purposes to be described As explained hereinabove, there may be times when it is desirable to provide for refrigeration without operating the Diesel engine. In certain States the laws prevent operation of the Diesel engine while traveling through tunnels. Likewise in certain large cities, terminal regulations forbid the operation of any internal combustion engine while the train is standing in the terminal. It is apparent, therefore, that under emergency condi tions, some means must be provided for providing the necessary cooling. In our arrange,- ment, as described hereinabove, the dynamoelectric machine I6 is arranged to operate as a motor to drive the compressor when cooling is required and when the Diesel engine is not operating. In order to provide for operation of the refrigerating system by the dynamo-electric machine operating as a motor, switches IOI, I03, I04, I05 and H2 are moved to closed position. As explained hereinabove these switches may be moved to closed position either manually or by means of automatic mechanism for simultaneously closing all of these switches. The circuits controlled by the switches IOI, I03 and I04, having been described hereinabove. no further description of these circuits is believed necessary at this point. Closing the switches I08 and H2 places the dynamo-electric machine II in operation under the control of the cooling pilot relay I92 which in turn is controlled by the thermostat I90 located in the passenger compartment of the vehicle. Thus upon the thermostat I98 closing, the circuit through the cooling pilot relay coil I92 is completed whereupon the switch I94 closes the circuit which opens the refrigerant valve 82 and also closes the circuit through the contacts I88 and the delayed-action relay coil I18. Since under these conditions, the switch I88 is closed, energization of the coil I18 causes the switch I14 to close after a predetermined time interval. The closing of the switch I14 closes the circuit through the delayed-action motor starter coil 200 which progressively moves the starter contact bar 202 into engagement with the motor starting contacts 204 which progressively serve to short out the armature starting resistances 208, in the usual well known manner. At the same time the field of the dynamo-electric machine I8 is suitably energized from the battery through the switch ,I12 which at this time is in the full line position. However, the delayed-action solenoid 200 does not become energized unless the switch 208 is in a closed position. It will be noted that upon simultaneous closing of the switches I05 and H2, the solenoid 208 is energized, through the closed switch 222. Upon energization of the solenoid 208, the switch 2I0 moves from its full line "position to its dotted line position, thereby energizing the solenoid coil 2I2, which in turn closes circuits through the switches 206, 2 and 2| 8.

Closing of switch 208 completes the circuit to the motor starter coil 200, the action of which has been described hereinabove. Closing of switch 2 maintains a circuit through the relay coil 2I2 whereby switches 206, 2 and H8 are maintained in the closed position under the control of switch I05 and the switch 2I0 which in turn is controlled by the relay coil 208. The coil 208 is energized directly from the battery and therefore interprets the battery output voltage. By virtue of this arrangement and the proper design of coil 208 the dynamo-electric machine is automatically disconnected from the battery when the battery voltage is below a predetermined minimum. When the battery voltage drops below this minimum the coil 208 releases switch 2I0 to its full line position thereby short circuiting relay coil 2I2 to open switc es 208, 2 and 2I8. Closing of the switch II2 energizes the delayed-action relay coil 220 which after a predetermined time delay opens the circuit through the switch 222 which in turn breaks the one circuit from the line 94 to the solenoid coil 208 thereby placing the solenoid 208 directly under the control of the switches I05 and 2 I8, as explained hereinabove. The delayedaction relay coil 220 opens the switch 222 after contacts 206, 2| 4 and 2I8 have reached their closed positions and does not reclose switch 222 until switch II2 has been opened in readiness for another motor starting cycle.

By virtue of the above arrangement. it is possible to use the dynamo-electric machine as a motor for driving the compressor independently of the Diesel engine. The dynamo-electric machine IG automatically de-clutches from the Diesel engine I4 whenever the Diesel engine stops, due to the fact that the pressure in the wind box of the Diesel engine automatically drops when the Diesel engine stops. In referring to the circuit diagram, it will also be noted that the valve 28 which controls the flow of compressed air from the wind box of the Diesel engine to the clutch is closed at all times when the electric circuit is set for operation of the dynamo-electric machine as a motor. Closing of the switch "I places the solenoid coll 280 under the control of heating thermostat 282. The solenoid 280 controls the switch 288 which in turn controls the solenoid valves 88 and 90. The arrangement being such that when the temperature inthe passenger compartment of the car drops below a predetermined value such as 75", the valve 88 leading to the re-heating coil 48 opens and the valve 90 leading to the coil 44 closes.

By virtue of the above described arrangement, it will be noted that the refrigerating system is caused to operate whenever the temperature in the car exceeds 74 and reheat of the air takes place whenever the car temperature is below 15. As a result of this arrangement, the refrigerating system turns on and off less frequently. Cycling of the compressor causes undesirable fluctuations in the moisture content of the air reaching the passengers since water accumulates on the coil during the ON cycle and is rapidly released to the air stream during the OFF cycle.

Briefly the following procedure is followed in operating the equipment whenever it is desired to provide ventilation only, switches Ill and I03 are closed. In the event that it is desirable to operate the Diesel without cooling. the switches I08 and I01 are also closed. If in addition to ventilation, it is desirable to provide cooling without using the Diesel engine, switches IOI, I08, I04, I05 and H2 should be closed. Whenever it is desired to operate the Diesel and provide cooling the switches IOI, I03, I04, I08 and I01 should all be closed.

While we have referred to the engine l4 as 9. Diesel engine, it is apparent that some features of our invention are equally applicable to other types of engines. Although we have described the thermostat I90 as controlling the refrigerant valve it is apparent that .the thermostat I90 may be used for clutching and declutching the compressor from its driving member so as to thereby,

control the amount of refrigeration supplied.

For purposes of illustration, the delayed-action relays have been shown as being of the type using a dashpot for retarding the operation thereof whereas other types of delayed action relays could be used equally well.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Air conditioning apparatus for a vehicle comprising in combination, an evaporator, a condenser, a compressor, refrigerantflow connections between said evaporator, compressor and condenser, means for flowing air to be conditioned in thermal exchange relationship with said evaporator, an internal combustion engine for driving said compressor, control means for said apparatus adapted to be mounted in a control compartment, and means for circulating conditioned air from said vehicle into said control compartment and thereafter into the intake manifold of said internal combustion engine.

2. In combination with a vehicle, apparatus for conditioning air for use in said vehicle comprising a compressor, a condenser, an evaporator, re-

irigerant flow connections between said compressor, condenser and evaporator, dynamo-electric means, a battery charged by said dynamoelectric means, internal combustion engine means for driving said compressor and said dynamoelectric means, a clutch between said internal combustion engine means and said compressor, means responsive to refrigerant pressure controlling said clutch, and means for operating said dynamo electric machine as a motor for driving said compressor.

3. In combination, a compressor, a condenser, an evaporator, refrigerant flow connections between said compressor, condenser and evaporator, dynamo-electric apparatus, an internal combustion engine for operating said compressor and for driving said dynamo-electric apparatus as a generator, a battery in circuit with said dynamoelectric apparatus, a clutch between said engine and said dynamo-electric apparatus, means including said battery for energizing said dynamoelectric apparatus as a motor for driving said compressor,- means responsive to energization of said dynamo-electric machine as a motor for rendering said clutch incapable of transmitting power from said dynamo-electric apparatus to said engine, a valve in said refrigerant flow connections between said condenser and said evaporator, a bypass refrigerant line between the outlet of said condenser and the inlet of said compressor, and a valve arranged in said bypass allowing flow of refrigerant from said condenser to said compressor when said first named valve is closed.

4. In a refrigerating system, a compressor, a condenser and an evaporator connected in refrigerant flow relationship, a Diesel engine, torque transmitting means between said engine and said compressor including a clutch, a dynamo-electric machine for operating said compressor, means responsive to the pressure within the wind box of said Diesel engine for declutching said clutch when said engine stops, a battery, said dynamoelectric machine being adapted to be operated by said engine as a generator to charge said battery when said engine operates, and means for energizing said dynamo-electric machine from said battery as a motor to drive said compressor when said engine is stopped.

5. Air conditioning apparatus for a vehicle comprising in combination, means forming a machinery compartment adjacent one corner of said vehicle, an internal combustion engine in said compartment, a refrigerant compressor driven by said engine, refrigerant evaporating and condensing means connected in refrigerant fiow relationship with said compressor, means for introducing engine cooling air in through an opening formed in the side of said vehicle, means for discharging said air through an opening formed in the end wall of said vehicle, and thermal means responsive to the temperature of the air flowing through said machinery compartment for controlling the flow of cooling air through said compartment.

6. In an engine driven air conditioning system, an evaporator, a compressor and a condenser connected in refrigerant flow relationship, an engine for driving said compressor, evaporator fan means for circulating airto be conditioned for an enclosure in thermal exchange relationship with said evaporator, condenser fan means for circulating cooling air over said condenser, xhaust fan means for discharging vitiated air from said enclosure, means for simultaneously supplying out operating either the evaporator fan means or the condenser fan means.

7. Air conditioning apparatus for a vehicle comprising in combination an evaporator, a condenser, a compressor, refrigerant flow connections between said evaporator, compressor and condenser, means for flowing air to be conditioned in thermal exchange relationship with said evaporator, an internal combustion engine for driving said compressor adapted to be mounted in a machinery compartment on said vehicle, means for circulating conditioned air from said vehicle into the intake manifold of said internal combustion engine, means for circulating outside air in thermal exchange relationship with said engine, and thermal means responsive to the temperature of the air flowing through said machinery compartment controlling the flow of said outside air in thermal exchange relationship with said engine.

8. In a refrigerating system, a compressor, a condenser and an evaporator connected in refrigerant flow relationship, a dynamo-electric machine, torque transmitting means between said dynamo-electric machine and said compressor, a Diesel engine, torque transmitting means between said engine and said dynamo-electric machine, a battery adapted to be charged by said dynamoelectric machine when said compressor is driven by said engine, a clutch in said last named means, means responsive to the pressure within the wind box of said engine controlling said clutch, and means including said battery for energizing said dynamo-electric machine as a motor to drive said compressor when said Diesel engine is declutched from said dynamo-electric machine.

9. In a refrigerating system, a compressor, a condenser and an evaporator connected in refrigerant flow relationship, a dynamo-electric machine, torque transmitting means between said dynamo-electric machine and said compressor, a Diesel engine, torque transmitting means between said engine and said dynamo-electric machine, a battery adapted to be charged by said dynamo-electric machine when said compressor is driven by said engine, a clutch in said last named means, means responsive to the pressure within the wind box of said engine controlling said clutch, means including said battery for energizing said dynamo-electric machine as a motor to drive said compressor when said Diesel engine is declutched from said dynamo-electric machine, and means responsive to the air temperature controlling the starting and stopping of said motor.

10. In a refrigerating system, a compressor, a condenser and an evaporator connected in refrigerant flow relationship, a Diesel engine, torque transmitting means between said engine and said compressor including a clutch, a dynamo-electric machine for operating said compressor when said clutch is declutched, means responsive to the pressure within the wind box of said Diesel engine for declutching said clutch when said engine stops, and means responsive to energization of said dying said clutch, a battery, said dynamo-electric machine being adapted to be operated by said engine as a generator to charge said battery when said engine operates, and means tor energizing said dynamo-electric machine irom said battery as a motor to drive said compressor when said engine is stopped. 4 4

DONALD r. manna. RICHARD n. coon). .mmzs R. HORNADAY.

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