FIELD OF INVENTION

[0001] The present relates to air conditioners and, in particular, to vehicle air conditioners.

[0002] The invention has been developed as an air conditioner for a recreational vehicle and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.

BACKGROUND

[0003] The following discussion of the prior art is intended to place the invention in an appropriate technical context and enable the associated advantages to be fully understood. However, any discussion of the prior art throughout the specification should not be considered as an admission that such art is widely known or forms part of the common general knowledge in the field.

[0004] Air conditioning systems are commonly used in order to make an environment more pleasing to its occupants. This is particularly relevant when the occupants are in a confined space, such as a caravan, mobile home or other recreational vehicle.

[0005] As used herein, the term‘recreational vehicle’ refers to motor homes, recreational vans, and other similar vehicles. Each of these has relatively confined spaces for the occupants to reside in and, as due to the nature of their use it is often that such vehicles are often used with a number of people, such as couples or families.

[0006] Conventional recreational vehicles have air conditioning systems that are built into the vehicle in some manner. For example, the air conditioning unit can be installed into the floor or roof and direct air around the interior cabin of the vehicles so that conditioned air is then provided to a particular area for the occupants.

[0007] One problem with roof mounted air conditioners is the operational noise they generate. This noise can be the result of excessive airflow or alternatively/additionally, operational noise of the air conditioner. With respect to the operational noise of a rooftop air conditioner, the sound is mainly due to the rotating components creating vibrations, which are then transmitted to the vehicle. [0008] It is known in the art to minimise the transmission of vibration by using isolation methods such as dampers and/or special mounts (generally rubber and/or springs) to mount some or all of the components of the air conditioner. However, a more effective method of reducing vibration is by reducing the source of the vibration.

[0009] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

SUMMARY OF THE INVENTION

[0010] According to the invention, there is provided an air conditioner for a vehicle, the air conditioner including:

a base mountable to the vehicle;

a compressor mounted to the base, the compressor being adapted to compress a refrigerant used in a refrigeration system

wherein the compressor includes one or more pairs of opposed cylinders such that vibration transmitted to the vehicle is generally reduced.

[001 1] In one embodiment, the compressor includes one pair of cylinders.

[0012] In one embodiment, the compressor is a dual cylinder rotary compressor.

[0013] In one embodiment, the compressor is mounted substantially horizontally to the base.

[0014] In one embodiment, the compressor includes a lubricating channel to distribute the oil from a sump to all the moving parts of the compressor.

[0015] In one embodiment, the air conditioner is adapted to be mounted to the roof of the vehicle.

[0016] In one embodiment, the air conditioner includes an inverter control for the compressor.

[0017] In one embodiment, the refrigeration system is mounted to the base. [0018] In one embodiment, the refrigeration system includes the compressor, a condenser coil and an evaporator coil such that the air conditioner is a packaged type air conditioner.

[0019] In one embodiment, the vehicle is a recreational vehicle.

[0020] Reference throughout this specification to“one embodiment”,“some embodiments” 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, appearances of the phrases“in one embodiment”,“in some embodiments” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0022] Figure 1 is a perspective view of a roof top air conditioner of the present invention according to one embodiment, shown installed on a recreational vehicle;

[0023] Figure 2 is a partly cut away perspective view of the roof top air conditioner of Figure 1 ;

[0024] Figure 3 is a perspective view of the air conditioner of Figure 1 shown without its top cover; and

[0025] Figure 4 is a perspective view of a compressor used in the roof top air conditioner of Figure 1 , shown with the outer cover removed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals throughout. In the following description, detailed descriptions of known functions and configurations incorporated herein have been omitted for conciseness and clarity.

[0027] Referring to the accompanying drawings and initially to Figure 1 , there is provided an air conditioner 10 for mounting on the rooftop of a recreational vehicle 12. The air conditioner is used for providing heated or cooled conditioned air to the inside of the vehicle. As shown, the vehicle 12 may be a recreational vehicle in the form of a van, motor home, trailer and the like, however, the air conditioner 10 may be used on other types of vehicles without departing from the scope of the invention. As used herein, the term recreational vehicle is intended to encompass all such motorized and non-motorized vehicles.

[0028] Referring now to Figure 2, the air conditioner 10 including an outer cover 16, is mounted on the vehicle rooftop directly above a corresponding air distribution box 30 mounted inside the vehicle. The air distribution box 30 draws inside air from the vehicle and directs it into the air conditioner 10. The inside air is then conditioned by passing through a compression refrigeration system 18 and returned to the vehicle through outlet ports in the air distribution box 30.

[0029] Referring now to Figure 3, which shows air conditioner 10 with its outer cover 16 removed to reveal its internal components. Air conditioner 10 includes a base 14 and a flange 18 for mounting the outer cover 16. Together, the base 14 and the cover 16 form an enclosure (shown in Figure 1 ) in which the compression refrigeration system 18 is housed. The compression refrigeration system 18 includes a rotary compressor 20, an evaporator coil 22 and a condenser coil 24, which are operatively coupled together in a known closed-loop manner.

[0030] More specifically, the compressor 20 compresses and raises the temperature of a refrigerant which is then delivered by a discharge line to the condenser coil 24. The compressed refrigerant is then cooled by outside air flowing around and through the condenser coil 24. The cooled refrigerant then travels towards the evaporator coil 22 where it flows through an expansion valve or similar device. The refrigerant traveling through the evaporator coil 22 absorbs heat from indoor air and is then returned by a suction line to the compressor 20. In this manner, the evaporator coil 22 and condenser coil 24 act as heat exchangers to remove heat from the indoor air and transfer that heat to the outside air.

[0031] As should be evident, illustrated air conditioner 10 is of the type known as a packaged air conditioner, whereby the refrigeration system including the evaporator coil and condenser coil are housed on a common base and within a common housing. This is contrary to a split type air conditioner, where the condenser components are housed remotely from the evaporator components. For this reason, the outer cover 16 has openings to respectively allow for the ingress and egress of outside air to the condenser heat exchange area of the air conditioner.

[0032] In prior art devices, the air conditioner would typically include a single cylinder rotary (or reciprocating) type compressor. Single cylinder rotary compressors have been used widely in air conditioning systems in the past due to their high efficiency, compact size and relatively low weight. However, single cylinder rotary compressors are known to induce significant vibrations due to rotational movement of the compression chamber. As should be appreciated, substantial vibrations in the present context are undesirable as they are transferred through the base pan 14 to the rooftop and then into the vehicle 12.

[0033] On the other hand, multi cylinder rotary compressors having an even number of cylinders, produce less vibrations than single cylinder compressors of similar compressible volume capacity. These compressors have at least one pair of generally opposed cylinders with relatively smaller cylinder volumes compared to a single cylinder compressor of comparable capacity. The cylinders are reciprocally driven by a common shaft, where one cylinder is pressurised and the other one is not, at each point of shaft rotation. Further, each pair of cylinders include two concentric journals and annular rollers, which are 180° out of phase. These features allow multi cylinder rotary compressors to advantageously have less vibration and be quieter in operation compared to single cylinder rotary compressors of comparable compressive volume.

[0034] For this reason and as best shown in Figure 4, according to one aspect, the present invention provides an air conditioner with a multi-cylinder rotary compressor 20. More particularly, the illustrated compressor 20 is a dual cylinder rotary compressor including a first cylinder 40, a second cylinder 42, input conduit 44, and output conduit 46. In this way, less noise and vibration are advantageously transmitted to the base pan 14 and rooftop of the vehicle during air conditioner operation. Moreover, it should be appreciated that vibration may be further reduced by using isolation mounts for mounting the compressor to the base pan.

[0035] A further advantage of a dual cylinder rotary compressors in the present application is that they are designed for substantial horizontal mounting, relative to the orientation of the internal cylinders. Therefore, according to the invention, compressor 20 is substantially horizontally mounted as best shown in Figure 3. By having a generally horizontally mounted compressor, less height clearance space is required for the outer cover 16, which in turn allows for an air conditioner with a lower profile to be installed on the vehicle rooftop, as best shown in Figure 1 . A lower profile for a roof top vehicle air conditioner is advantageous because there is less aerodynamic drag on the vehicle 12. A further advantage, especially for a rooftop air conditioner mounted on recreational vehicles, is that the lower profile provides additional clearance for carports, trees and other obstacles resulting in less challenging manoeuvring of the vehicle for the driver.

[0036] It should also be appreciated that maintenance of a rooftop air conditioner on a recreational vehicle can be difficult due to the possible remote location of the vehicle if a fault occurs. Moreover, due to the air conditioner being mounted on the roof, there are potential safety concerns in terms of climbing on the vehicle roof for repairs/maintenance or the replacing of heavy parts. These problems may, to some extent, be ameliorated by having an air conditioner that has a more reliable operation. It is for this reason that compressor 20 of the present invention advantageously includes a two-stage differential pressure oil supply structure designed to reduce refrigeration oil in compression. This structure guides high temperature and high-pressure refrigerant gas discharged from the cylinders of the compressor through gaps in the stator and rotor to the top cover of the compressor. Flowing the refrigerant gas in this way induces cooling by using the principle of forced convection heat transfer. By providing this internal structure, the amount of oil discharged from the compressor is effectively reduced and the cooling effect on the motor is improved to reduce heat stress and improve the operational reliability of the compressor.

[0037] A further feature for improving reliability of the air conditioner 10 is that dual cylinder compressor 20 also includes a lubricating channel to distribute the oil from a sump to all the moving parts of the compressor. Advantageously, this lubricating channel improves lubrication and reduces the overall size of the compressor due to only requiring a small capacity sump. These features make compressor 20 of the present invention more reliable and extend the service life.

[0038] In some embodiments, an inverter (not shown) will be provided to control the speed of the compressor motor, so as to continuously regulate the temperature of the inside of the vehicle. [0039] Advantageously, the present invention provides a vehicle roof top air conditioner that is quieter and transmits less vibration to the inside of a vehicle in operation than prior art vehicle roof top air conditioners. Occupants within the vehicle are therefore more comfortable. The illustrated vehicle roof top air conditioner also has a relatively smaller frontal profile resulting in less aerodynamic drag and therefore less motive energy is required to move the vehicle especially at highway speeds. Having a smaller frontal profile also results in less wind noise while the vehicle is moving. The vehicle is advantageously more able to avoid low hanging tree branches and able to fit more easily under carports and into garages.

[0040] In the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, Figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

[0041] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0042] While there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as falling within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.