Electric drive compressor system

Abstract

An electric drive compressor system (1) comprising: a reciprocating compressor (2) having temperature and pressure sensors (83, 84) for sensing a pressure and temperature of gas prior to compression by the compressor (1) and for sensing a pressure and temperature of gas after compression by the compressor (1); a motor (3) connected to the compressor (1) for driving the compressor (1); a cooling system (4) for cooling the motor (3); and a controller (5) for controlling the motor (3) in real time based on the temperature and pressure sensor readings of the gas prior to and after compression by the compressor (1). Features and advantages of the systems (1) as exemplified are as follows: lightweight and compact design; refrigerant circuit sealed from electric motor for ease of maintenance and service; air cooled from unique fin and airflow passage design, with fan width pulse width modulation; intelligent control system with pressure and temperature sensors/transducers and software; separate compressor working assembly to ensure piston alignment and compression is not affected by heat distortion; separate outer housing and compressor crankcase to ensure leak free operation.

Claims

1. An electric drive compressor system comprising: a swashplate compressor having: a compressor housing with a front end and a rear end; a gas intake/suction port and a gas discharge port located at the front end of the compressor housing; a valve plate compartment having a high pressure sub-compartment which is in direct fluid communication with the gas discharge port and a low pressure sub-compartment which is in direct fluid communication with the gas intake/suction port; and a first dual temperature and pressure sensor and a second dual temperature and pressure sensor located near the rear end and inside of openings of the compressor housing, the first dual temperature and pressure sensor has at least sensing region located within the low pressure sub-compartment for sensing the temperature and pressure of the gas in the low pressure sub-compartment, the second dual temperature and pressure sensor has at least sensing region located within the high pressure sub-compartment for sensing the temperature and pressure of the gas in the high pressure sub-compartment, such that the first dual temperature and pressure sensor and the second dual temperature and pressure sensor simultaneously sense the pressure and temperature of the gas prior to and after compression by the compressor; a motor connected to the compressor for driving the compressor; a cooling system for cooling the motor, said cooling system comprises a fan connected to the motor and operated independently of the motor, a fan control, and a housing cooling arrangement for cooling at least the motor, and the fan control simultaneously receives the readings from the first dual temperature and pressure sensor and the second dual temperature and pressure sensor; and a controller comprising a microcontroller, contacts/electrical sockets electrically connected to the first dual temperature and pressure sensor and the second dual temperature and pressure sensor for receiving readings therefrom, and contacts/electrical sockets respectively for the motor and the fan, and wherein the controller simultaneously control the motor and fan in real time based on the simultaneously taken readings of the first and second dual temperature and pressure sensors of the gas prior to and after compression by the compressor.

2. The electric drive compressor system according to claim 1, wherein the motor drives the compressor in a manner such that the motor and compressor be separated from each other without interrupting a refrigerant circuit of the compressor, wherein said compressor comprises a compressor drive shaft seal that extends around a drive shaft of the compressor and prevents leakage of refrigerant from the compressor, and wherein said motor comprises a motor drive shaft seal that extends around a drive shaft of the motor and prevents ingress of refrigerant.

3. A method of operating an electric drive compressor system comprising: a swashplate compressor having: a compressor housing with a front end and a rear end; a gas intake/suction port and a gas discharge port located at the front end of the compressor housing; a valve plate compartment having a high pressure sub-compartment which is in direct fluid communication with the gas discharge port and a low pressure sub-compartment which is in direct fluid communication with the gas intake/suction port; and a first dual temperature and pressure sensor and a second dual temperature and pressure sensor located near the rear end and inside of openings of the compressor housing, the first dual temperature and pressure sensor has at least sensing region located within the low pressure sub-compartment for sensing the temperature and pressure of the gas in the low pressure sub-compartment, the second dual temperature and pressure sensor has at least sensing region located within the high pressure sub-compartment for sensing the temperature and pressure of the gas in the high pressure sub-compartment, such that the first dual temperature and pressure sensor and the second dual temperature and pressure sensor simultaneously sense the pressure and temperature of the gas prior to and after compression by the compressor; a motor connected to the compressor for driving the compressor; and a cooling system for cooling the motor, said cooling system comprises a fan connected to the motor and operated independently of the motor, a fan control, and a housing cooling arrangement for cooling at least the motor, and the fan control simultaneously receives the readings from the first dual temperature and pressure sensor and the second dual temperature and pressure sensor; and a controller comprising a microcontroller, contacts/electrical sockets electrically connected to the first dual temperature and pressure sensor and the second dual temperature and pressure sensor for receiving readings therefrom, and contacts/electrical sockets respectively for the motor and the fan, wherein said method comprises the step of using the controller to simultaneously control a switch on, shut down and speed of the motor and fan in real time based on the simultaneously taken readings of said first and second dual temperature and pressure sensors of the gas prior to and after compression by the compressor.

Description

BRIEF DESCRIPTION OF FIGURES

(1) Various embodiments of the invention will be described with reference to the following figures.

(2) FIG. 1 is a partially exploded view of an electric drive compressor system that includes a compressor, motor, cooling system and controller, according to an embodiment of the present invention.

(3) FIG. 2 is a side elevation view and part detailed view of the compressor shown in FIG. 1.

(4) FIG. 3 is an exploded view of part of the compressor shown in FIG. 2.

(5) FIG. 4 is a partial exploded view of the compressor and cooling system shown in FIG. 2.

(6) FIG. 5 is a partial exploded view of the motor and cooling system shown in FIG. 1.

(7) FIG. 6 is an end view showing an exterior region of a rear wall of the motor housing.

(8) FIG. 7 is a block diagram of an embodiment of the invention, showing the controller.

(9) FIG. 8 is an operational flowchart of the controller, relating to maximum running conditions.

(10) FIG. 9 is a partial exploded view of the compressor assembly shown in FIG. 1.

(11) FIG. 10 is a partial exploded view of the motor and cooling system shown in FIG. 1.

(12) FIG. 11 is a perspective view of the electric drive compressor system of FIG. 1.

(13) FIG. 12 is a side elevation view of the electric drive compressor system of FIG. 1.

(14) FIG. 13 is a rear perspective view of part of the system shown in FIG. 12.

(15) FIG. 14 is a perspective view of part of the motor housing, controller and fan cover shown in FIG. 1.

(16) FIG. 15 are images of a user interface of the system of FIG. 1.

(17) FIGS. 16-21 give details of various electric drive compressor systems, according to other embodiments of the present invention.

(18) FIG. 22 is another partially exploded view of the electric drive compressor system shown in FIG. 1.

(19) FIG. 23 is a partial exploded view of part of the compressor system shown in FIG. 1.

(20) FIG. 24 is a perspective view of what is within the controller housing of the system shown in FIG. 1.

DESCRIPTION OF EMBODIMENTS

(21) Preferred features, embodiments and variations of the invention may be discerned from this section, which provides sufficient information for those skilled in the art to perform the invention. This section is not to be regarded as limiting the scope of any preceding section in any way.

(22) In the figures like reference numerals refer to like parts.

(23) Referring first to FIGS. 1 to 14 and 22 to 24, there is shown an electric drive compressor system 1 that includes a reciprocating compressor 2 having dual temperature and pressure sensors 83, 84, a motor 3 for driving the compressor 2, a cooling system 4 for cooling at least the motor 3, and a controller 5 for controlling the motor 3 and cooling system 4 based on temperature and pressure sensor readings.

(24) The compressor 2 has a front end 20 and a rear end 21 and includes a compressor housing 22 (case), a first discharge valve plate 23, a first gasket 24, a first suction valve plate 25, a first cylinder block 26, five piston assemblies 27, a first thrust bearing 28, ten shoe discs and balls 29,70, a swashplate 71, a compressor drive shaft 72, a locking pin 73, a second thrust bearing 74, a second cylinder block 75, a needle bearing 76, a second suction valve plate 77, a second gasket 78, and a second discharge valve plate 79. This compressor 2 design has largely been described in Japanese patent publication number 60-104783, the entire contents of which are incorporated herein by way of cross-reference.

(25) The compressor housing 22 includes a main cylindrical housing 80 having a cylindrical sidewall and a front cap/front end wall 81 that is fastened to the main housing 80 by way of mechanical fasteners. The compressor 2 has feet 82 that are attached to the main housing 80 by way of mechanical fasteners.

(26) The compressor 2 includes dual pressure and temperature sensors 83, 84 located near a rear end of the compressor housing 21, as well as a gas intake/suction port 85 and a gas discharge port 86 located at a front end of the compressor housing 22.

(27) The compressor housing 22 has various openings for other compressor components such as the dual pressure and temperature sensors 83 (discharge side), 84 (suction side), two sight glasses 87, an oil return port 88, an oil drain plug 89, a relief valve 90, and plugs 91 for the gas intake/suction 85 and discharge ports 86.

(28) The valve plates 23, 25, 77, 79, gaskets 24, 78, cylinder blocks 26, 75, piston assemblies 27, swashplate 71 and compressor shaft 72 etc constitute a working assembly 92 that is situated within the compressor housing 22. The compressor 2 includes a valve plate compartment 93 located between the discharge valve plate 79 and rear end of the compressor housing 21. The valve plate compartment 93 has two sub-compartments, one of which is under high pressure and is in direct fluid communication with the discharge port 86 and one of which is under low pressure and is in direct fluid communication with the intake/suction port 85.

(29) The dual pressure and temperature sensors 83, 84 are, in a preferred embodiment, model number TEM00875 as manufactured by Sensata Technologies. Each sensor 83, 84 includes: a sensing region comprising a thermistor 830, 840 at a lower end of the sensor 83, 84 and a pressure plate 837, 847 located above the thermistor 830, 840; a threaded body 831, 841; and a sensor lead wire/contact 832, 842 that is connectable to the controller 5, as shown in FIGS. 11 and 12. The threaded body 831, 841 of each sensor 83, 84 is received within a respective threaded opening 835, 845 in the main motor body 32. A first sensor monitors the temperature and pressure of gas within one sub-compartment and a second sensor monitors temperature and pressure of gas within the other sub-compartment. In this way, the sensors 83, 84 monitor the temperature and pressure of the incoming (prior to compression) and discharged (after compression) gas/refrigerant.

(30) The swashplate 71 is an elliptical disk that is mounted at an angle to the compressor drive shaft 72. The drive shaft 72 extends through the thrust bearings 28, 74, each of which engages a boss 260, 750 of a cylinder block 26, 75. The drive shaft 72 extends through a central bore 261, 751 of each cylinder block 26, 75. One end 720 of the drive shaft 72 is splined/keyed and extends through a boss 210 of the rear wall of the compressor housing 22 in a sealed manner, for connection to an end of the drive shaft of the motor 3. The other end of the compressor shaft 721 extends within the needle bearing 76, which bearing 76 locates within a central bore 751 of a cylinder block 75.

(31) Each piston assembly 27 includes a pair of axially opposed pistons 271, 272. A head of each piston 271, 272 has a sealing ring 273, 274. Another end of each piston 271, 272 has a socket 275, 276, for receiving a ball 70. Each cylinder block 26, 75 has a cylindrical bore 262, 752 of the cylinder block 26, 75 within which slides a piston 271, 272. The socket end of each piston engages the swashplate 71 by way of a shoe disc 29 and a ball 70 that rides within a socket of the shoe disc 29 and the socket 275, 276 of the piston. The shoe disc 29 (slipper disc) slides on the swashplate 71. As the compressor drive shaft 72 rotates the swashplate 71, the pistons 271, 272 are caused to move in a reciprocating manner parallel with the compressor drive shaft 72 within the cylindrical bores 262, 752. This reciprocating motion draws gas through the intake port 85 and further through the low pressure sub-chamber of the valve compartment 93 and discharges compressed gas through the discharge port 86 via the high pressure sub-chamber of the valve compartment 93.

(32) The compressor housing 22 is fluid-tight and so no gas is able to escape from the compressor 2 to the environment, including into the motor 3.

(33) The compressor housing 22 has radially extending airflow passages in the form of cooling fins 220 that extend parallel with the compressor drive shaft 72. These fins 220 can be part of the cooling system 4.

(34) The motor 3 is most clearly shown in FIGS. 1, 5, 6, 9 and 10, and has a front end 30 and a rear end 31. The motor 3 has a brushless DC motor drive and includes a motor housing 32 having a front end 30 and a rear end 31, a motor drive shaft 33, a rotor 34, a stator (containing winding) 35, first and second bearings 36, 37, and lead wires/contacts 38. A temperature sensor (not shown) is connected to the stator 35 housing. A motor position sensor/speed sensor/Hall-effect sensor (not shown) for monitoring the position/speed of the motor drive is connected to a rear cap/end wall 322 of the motor housing 32.

(35) The motor drive shaft 33 has a hollow cylinder 335 having a front end 330 and a rear end 331. The front end 330 is supported within a ball bearing 37 at the front end 30 of the motor housing 32. The rear end 331 of the hollow cylinder 335 extends around a ball bearing 36 at the rear end of the motor housing 31. The motor drive shaft 33 includes a splined/keyed socket 332 located within the hollow cylinder 335, at the front end 330 of the hollow cylinder 335. The splined/keyed socket 332 is sized to firmly engage with the splined/keyed end 720 of the compressor drive shaft 72.

(36) The motor housing 32 includes a main cylindrical housing 320 having a cylindrical sidewall, a front cap/front end wall 321, a rear cap/rear end wall 322, and feet 323.

(37) Both caps/end walls 321, 322 are fastened to the main housing 320 by way of mechanical fasteners. The feet 323 are connected to the main cylindrical housing 320 by way of mechanical fasteners.

(38) The front end wall 321 of the motor housing has a recess that supports a ball bearing 37. The rear end wall 322 of the motor housing has a boss 325 about which extends a ball bearing 36. The front end wall 321 of the motor housing has a central opening 326 that receives the splined/keyed end 720 of the compressor drive shaft 72 in a sealed manner. The rear wall 322 of the motor housing 32 has a recess 327 adapted to mount a fan motor of the cooling system 4.

(39) The motor housing 32 has airflow passages in the form of radially extending cooling fins 350 and enclosed airflow passages 351 that extend substantially parallel with the motor drive shaft 33 through which cooling air can flow. When viewed on end, the motor housing's exterior/perimeter is similar to a honeycomb structure with airflow passages 350, 351 resembling cells of a honeycomb, as seen in FIGS. 6, 9 and 10. A housing of the controller 5 and fins 350 create further airflow passages, similar to those numbered 351. The airflow passages 350, 351 can be part of the cooling system 4.

(40) The motor 3 is controlled by the controller 5. Motor lead wires/contacts 38 extend from the controller 5 to the stator 35 via the rear end wall 322, as seen in FIG. 10. When powered, the rotor 34 and motor drive shaft 33 rotate within the stator 35, and the motor drive shaft 33 turns the compressor drive shaft 72.

(41) The motor housing 32 can be disconnected from the compressor housing 22. Mechanical fasteners (nuts and bolts) are secured through eyelets of the compressor main housing 80 and passages of the motor housing 320.

(42) If using a flammable refrigerant, then the motor 3 can have an additional drive shaft seal (not shown) that extends around the drive shaft 33 of the motor 3 at the front end 30 of the motor housing 32. This additional seal prevents flammable gas from reaching electronic components of the motor 3.

(43) The cooling system 4 includes a fan 40, fan control 41 and housing cooling arrangement that includes the airflow passages 351 and 350 of the motor housing, the airflow passages 220 of the compressor housing 22, and the airflow passages/downwardly extending fins (not shown) of the controller housing 50.

(44) As best seen in FIGS. 1, 5, 9 and 10, the fan 40 includes a mounting base plate 400, motor 401 having a drive shaft, impeller 402 and lead wire/contact 403. The mounting base plate 400 is mounted within the rear wall 322 of the motor housing by way of mechanical fasteners. The motor 401 is situated between the base 400 and the impeller 402. The drive shaft of the motor 401 engages a central opening in a hub of the impeller 402, and the impeller 402 spins within an annular groove of the rear wall 322. Blades of the impeller 402 are orientated so as to force air into the airflow passages 350, 351 of the motor housing 32. The fan lead wire/contact 403 extends through the rear end wall 322 of the motor housing.

(45) The housing cooling arrangement includes a fan cover 404 that extends over the impeller 402 and is connected to the rear end wall 322 of the motor housing 32 by way of mechanical fasteners. The fan cover 404 has air inlets 405 in the form of a grill for drawing in air (at ambient temperature) from outside the fan cover 404. The fan cover 404 has air discharge guide vanes 407 and a chute 406 for directing that air into the airflow passages 350 and 351, as seen in FIGS. 10, 13 and 14. Air is directed through the airflow passages 350, 351 that are located about a periphery of the motor housing 32, including between a top of the motor housing 32 and a housing 50 and fins (not shown) of the controller 5, as best seen in FIGS. 6, 9 and 13.

(46) When the fan 40 is operated, cooling air is drawn within the inlets 405 and the impeller 402 plus air discharge guide vanes 407 and chute 406 direct the cooling air through the airflow passages 350, 351 and further between the airflow fins 220 of the compressor housing 80. In this way, both the motor 3 and the compressor 2 are cooled by that air. Also, electronics of the controller 5 are cooled by airflow between the fins 350 and the controller housing 50 and its fins. No refrigerant is sacrificed by passing it through the motor housing 32, as would be done conventionally.

(47) The fan cover 404 includes baffles 409 located between the air inlets 405 and fan motor 401, for preventing water entering the fan cover 404 from reaching electronic componentry of the fan or motor.

(48) Referring now to FIGS. 1, 7, 9, 10, 11, 12, 13, 22 and 24, the controller 5 includes a controller housing 50, a microcontroller 51 (or other logic circuitry), contacts/electrical sockets for the wire leads/contacts of the dual temperature and pressure sensors 83, 84 for engagement of the sensors with the controller housing 50, a temperature sensor 52 (located on the stator housing) for sensing the temperature of the motor 3, contacts/electrical sockets for the motor wire/contacts 38 and fan lead wires/contacts 403, a DC to DC converter 53, a transceiver module 54, a CAN/LIN communication interface 55, power amplifiers, power level shifters, transistors and other circuitry. The controller 5 is connectable to a power supply 56 via the DC/DC converter 53. The controller housing 50 is connectable to the motor housing 32 by way of mounting fins and mechanical fasteners (see the mounting screws and controller housing tabs that receive those screws in FIG. 12).

(49) The controller housing 50 contains the electronic circuitry and components 500, as seen in FIG. 24. The controller housing 50 has a side wall 501, a flattened top wall 502 and a bottom wall 503. The top wall 502 is removable, as seen in FIG. 24. The side wall 501 has an opening 505 through which extends a power cord (not shown) in a substantially sealed manner. Cooling fins (not shown) extend downwardly from the bottom wall 503. The bottom wall 503 has openings (not shown) for the fan, motor and sensor lead wires or contacts 832, 842, 38, 403. The top wall 502 has a polycarbonate area corresponding to an antennae 508 of a transceiver module 54.

(50) The controller 5 includes a microcontroller 51 electrically connected to the dual temperature and pressure sensors 83, 84, for receiving input from those sensors 83, 84. The microcontroller 51 is electrically connected to a temperature sensor 52 associated with the motor 3, for receiving input from that sensor 52. The microcontroller 51 is electrically connected to speed/position sensors 57 associated with the motor 3 for receiving input from those sensors 57.

(51) The microcontroller 51 is electrically connected to the cooling fan 40, via fan control 41, for managing the rotational speed of the cooling fan 40. The fan control 41 utilises pulse-width modulation to provide control signals to the cooling fan 40.

(52) The microcontroller 51 has motor speed control for managing the rotational speed of the motor 3. The motor speed control employs power amplifiers and transistors in the form of high and low side gate drivers 58 and MOSFET 59 switches.

(53) The controller 5 is connected to 600 VDC and includes a DC to DC converter 53. The DC to DC converter 53 is connected to the high side gate drivers 58 and microcontroller 51. The 600 VDC 56 is connected to the MOSFET switches 59 to provide voltage thereto.

(54) The controller 5 includes a wireless (3G or 4G) transceiver module 54 for both transmitting and receiving data wirelessly between the microcontroller 51 and a remote device, such as a PC, website or other user interface. The antennae 508 of the transceiver module is located within the top wall 502 of the controller housing 50.

(55) The control 5 includes a CAN/LIN communication interface 55, enabling communication between the microcontroller 51 and other applications/devices/user interface/server/receiver.

(56) The system 1, as exemplified, enhances compressor performance during normal system operation and provides protection in unfavourable conditions or from a specific system fault.

(57) The system uses logic control to protect the compressor 2 from excessive pressure and thermal loads, and can be customised across a range of discharge and suction side pressures, and thermal parameters. In addition to baseline parameter settings, the controller software/firmware can be pre-programmed to the type of refrigerant, compressor size and system designed to enhance compressor performance and protection specific to the characteristics of the relative refrigerant.

(58) The controller 5 is configured with logic designed to process the parameters obtained by the sensors 83, 84, 52 and 57, and control operating parameters to ensure desired operation of the system. Through the reconfigurable software of the controller 5, safety and operational parameters can be set for the suction and discharge pressures, excessive compressor body temperatures, excessive suction line and discharge superheat. This functionality gives an end user the ability to tailor or fine tune the controller 5 and overall system.

(59) Connection to the controller 5 can be made via CAN bus (Controller Area Network), LIN bus (Local Interconnect Network) connections 55 to allow (substantially) real time viewing of compressor 2 parameters and operation. The 3G/4G transceiver module 54 provides online connection and data transmission to a web interface or other web portal as required. Images of the user interface are shown in FIG. 15.

(60) The dual temperature-pressure sensors 83, 84 are used to simultaneously measure the pressure and temperature of the gas at both the high and low side of the compressor 2, from the top of the valve plate 79. Sensor data is transferred to the controller 5 and a series of predefined commands, as shown in the flowchart of FIG. 8, will adjust the compressor 2 to optimise its performance.

(61) Maximum running conditions are shown in the flowchart of FIG. 8. Operating parameters to be used by the controller 5 are configured by way of a user interface in wireless communication with the controller 5 via the 3G/4G transceiver module 54. The controller receives an indication of the refrigerant/gas pressure via the temperature/pressure sensors, then a control signal is sent to start the motor 3. The motor's temperature is monitored via the temperature sensor 52, and the speed of the motor is modified via the MOSFET switches 59 as required.

(62) The compressor 2 is started. The temperature and pressure of the suction line and discharge line are monitored by the temperature/pressure sensors 83 and 84, respectively. The controller 5 modifies the motor's speed as required to ensure optimal operating conditions.

(63) The electric drive compressor systems as exemplified can utilise 10 or 14 cylinder swashplate technology, and have a capacity ranging from 150 cc to 680 cc. These have a specific electric drive motor with either brushless DC (BLDC) or switch reluctant (SRM) variations, available in 750 VDC, 600 VDC or 24 VDC configurations, and are compatible with refrigerants such as R134a, R404a, R452a and R1234yf.

(64) The electric drive compressor system 1 is usually connected into a refrigerant circuit containing refrigerant and operated by way of the following steps: 1. Hoses of the circuit are connected to the intake/suction and discharge ports of the compressor. 2. Compressor oil checks are carried out, checking for leaks at the compressor connections and other connections. 3. Air is evacuated from the refrigerant circuit using a vacuum pump. 4. A charging step is utilised, whereby the system is filled with a final refrigerant via an approved point in the refrigerant circuit, in accordance with manufacturer recommendations and following ISO and ASHRAE. 5. The controller is connected to a remote receiver such as a user interface, PC, web portal, laptop or Android system using a wireless connection or wired connection (eg. Bluetooth, USB, LIN, CAN or USB connection). 6. Software/firmware is run on the remote receiver. 7. A user interface is utilised to enter system parameters and checking and/or changing pressure and temperature settings to ensure that they are in line with manufacturer recommendations for the refrigerant circuit that the electric drive compressor system is connected to. 8. The current refrigerant pressure level is checked to ensure that the system is ready to commission/switch on. 9. Pressure and temperature data from the compressor sensors are monitored at the same time, in real-time. 10. The controller decides whether to turn the motor on or off, or to run the motor at a different speed. In turn, this will affect the compressor's speed. 11. Temperature reading are taken of the motor, and the controller decides whether or not to cool the motor. 12. The fan control receives pressure and temperature data from the intake/suction and discharge ports of the compressor at the same time, and the controller makes a decision based on that data whether to turn the cooling fan on or off, or to run the fan at a specific speed. 13. The motor control and fan control steps are carried out simultaneously in real-time based on temperature and pressure data coming from the sensors of the compressor.

(65) These systems 1 as exemplified (see also the systems 1 in FIGS. 16 to 21) are small and lightweight, and hence are highly portable and compact. They have a uniquely designed housing cooling system assisted by a PWM controlled fan at the rear of the motor. The fan operates independently of the motor. That is, the motor driveshaft does not drive the fan.

(66) The motor and compressor can be separated from each other without interrupting the refrigerant circuit.

(67) The motor can have an additional drive shaft seal should the refrigerant be flammable.

(68) The systems 1 are ideal for mobile air-conditioning and refrigeration applications where electricity supply is a prime source of power. This includes rail, mining, electric bus and industrial applications.

(69) Features and advantages of the systems 1 as exemplified are as follows: lightweight and compact design refrigerant circuit sealed from electric motor for ease of maintenance and service air cooled from unique fin and airflow passage design, with fan width pulse width modulation intelligent control system with pressure-temperature sensors/transducers and software separate compressor working assembly to ensure piston alignment and compression is not affected by heat distortion separate outer housing and compressor crankcase to ensure leak free operation smooth operation and high volumetric efficiency from 10 and 14 cylinder swashplate working assemblies heavy duty impressed steel gaskets, high-temperature O-rings and double lip shaft seal CAN and LIN connectivity with modem for online data and web transmission

(70) In the present specification and claims (if any), the word comprising and its derivatives including comprises and comprise include each of the stated integers but does not exclude the inclusion of one or more further integers.

(71) Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases in one embodiment or in an embodiment in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

(72) In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.