ARRANGEMENT IN AN AIR-CONDITIONING SYSTEM INTENDED FOR A MOTOR VEHICLE

Abstract: The present invention relates to an arrangement in an air conditioning system (1) intended for motor vehicles, especially passenger cars. The air conditioning system (1) comprises a compressor (5), a condenser (2), and an evaporator (3), which are connected by way of transfer elements (6, 7, 8, 9) in a closed circuit for the transfer of refrigerant. The condenser (2) and the evaporator (3) are arranged on the chassis of the vehicle. The invention is characterised in that the compressor (5) is mounted on the chassis of the vehicle.

Description: Arrangement in an air conditioning system intended for a motor vehicle The present invention relates to an arrangement in an air conditioning system intended for motor vehicles, especially passenger cars, and comprising a compressor, a condenser and an evaporator, which by way of transfer elements are connected in a closed circuit for transferring the refrigerant, the condenser and the evaporator being arranged on the chassis of the vehicle. US-A-5 182 922 describes an air conditioning system intended for cars, which has a condenser and an evaporator fixed to the chassis of the car and a compressor mounted on the car's drive motor. In order to damp vibrations, the drive motor is fixed to the chassis by means of sprung fixing elements. Fluid connection elements are arranged between the compressor and the condenser and between the compressor and the evaporator. The said fluid connection elements comprise rigid pipeline sections in at least three different planes, between which pipeline sections at least one flexible connecting element is arranged, which is located in an area that is rotatable so that the pipeline sections can move in relation to one another. The fluid connection elements comprising rigid pipelines are intended to reduce the leakage of refrigerant to the surroundings and to prevent moisture getting into the air conditioning system. The present invention seeks to produce an air conditioning system for motor vehicles that represents an improvement on the prior art. This is achieved by means of an arrangement of the type referred to in the introductory part, which is characterised in that both the compressor, the condenser and the evaporator are mechanically connected to the chassis of the vehicle. Preferred embodiments have any or some of the characteristics specified in the subordinate claims. The arrangement according to the invention has a number of advantages compared to the prior art. Since the vehicle's drive motor does not have to be used for operation of the compressor, the refrigeration output of the compressor is more freely controllable according to requirements, rather than according to what the drive motor will permit in respect of the number of revolutions. Since the location of the compressor is no longer determined by the position of the drive motor, this increases the scope when choosing the location of the air conditioning system components, such as the compressor, the condenser and the evaporator. With greater freedom of location, the components can be located closer to one another, the pipelines between the components becoming shorter, thereby reducing the risk of leakage. This is advantageous both with regard to the operating costs of the air conditioning system and from an environmental standpoint, since nowadays efforts are being made to reduce or completely eliminate the use of Freons, among other things. The risk of leakage is also reduced in that the pipelines can be made of a rigid material, such as metal or plastic, for example. Due to the fact that the compressor, the condenser and the evaporator are all arranged on the vehicle chassis, shear movements between these components owing to vibrations are reduced. It is therefore less essential that the pipelines be flexible so that the components are somewhat displaceable in relation to one another. The invention will be explained in more detail below with reference to the figure and with the aid of examples of embodiments of the arrangement according to the invention. The figure shows an air conditioning system according to one example of the present invention. In the figure the reference number 1 denotes an air conditioning system intended for motor vehicles and in particular for passenger cars. The air conditioning system 1 is designed to influence the climate in the passenger compartment of the vehicle. The system 1 comprises a condenser 2, an evaporator 3, a drying filter 4 and a compressor 5. The pipelines 6, 7, 8, 9 for transferring refrigerant connect the condenser 2, the evaporator 3, the drying filter 4 and the compressor 5 to form a closed circuit. The pipelines may be jointless. The refrigerant may be Rl 2 Freon (CFC) or Rl 34a (HFC), for example, the latter becoming more and more common for environmental reasons. The pipeline 6 carries refrigerant in liquid form from the condenser 2 to the evaporator 3. In the evaporator the pressure of the refrigerant is reduced, as a result of which it is converted into a vapour. The refrigerant in vapour form is conveyed via the pipeline 7 to the drying filter 4 and by way of the pipeline 8 onwards to the compressor 5. In the compressor 5 the pressure of the vapour is increased. The vapour thereafter leaves the compressor 5 to be returned via the pipeline 9 to the condenser 2, where the vapour at the same pressure is converted to liquid. In one embodiment the compressor 5 is driven by a separate compressor motor, for example an electric motor 5a arranged on the chassis adjacent to the compressor. In another embodiment (not shown) there is a transfer between the compressor and a motor present in the vehicle, for example the drive motor, the compressor being driven by the motor. The separate motor and the transfer therefore make it possible to fit the compressor 5 separately from the vehicle's drive motor. This provides scope for less restricted locating of the parts in the air conditioning system. The parts can then be fitted so as to keep the length of the pipelines 6, 7, 8, 9 as short as possible. There is also the option of fitting the parts so that they are as easily accessible as possible, for servicing, for example, or with a view to the weight distribution in the vehicle. In the example in figure 4 the compressor 5, the condenser 2, the evaporator 3 and the drying filter 4 are all fitted to the vehicle chassis. The compressor 5, the evaporator 3 and the drying filter 4 are fitted along the longitudinal side of the chassis and the condenser 2 is fitted next to the vehicle's radiator (not shown). In one embodiment the compressor and the compressor motor are combined into one unit. In the passenger compartment controls (not shown) are arranged for controlling the air conditioning system. If the compressor 5 is driven by means of separate motor intended for the compressor, for example by an electric motor, the compressor motor may be adjustable in order to control its output according to the cooling requirement in the passenger compartment, without being restricted by the power output of the vehicle's drive motor. The cooling requirement can be calculated by the air conditioning system on the basis of environmental factors (the outside temperature and solar radiation, for example), the control settings (selected passenger compartment temperature, for example) and the present passenger compartment temperature. If the car motor is a petrol or diesel engine, according to a conventional solution its engine speed should limit the output of a compressor fitted to the engine, which is a disadvantage when idling or driving at low revs, for example. It should be mentioned that on certain car models the problem of the restriction imposed by the engine speed has been partially circumvented by incorporating a function into the refrigeration system, which when required acts on the engine system so that the idling speed is increased when the air conditioning system is in operation. For the person skilled in the art, however, there are a number of disadvantages attached to the increased idling speed. Naturally it is also possible to imagine that the compressor motor might be fed with drive current from some current source that is not located adjacent to the actual compressor. For example the compressor might be fed with current from the vehicle battery or batteries. This is now practically feasible in electric and hybrid cars. Even vehicles with a combined alternator and starter motor, so-called "dynamotors", could provide the vehicle with sufficient electricity in order to drive the compressor. Fitting the compressor 5 on the chassis of the vehicle rather than a petrol or diesel engine means that the compressor 5 is exposed to vibrations with a lower amplitude. Fitting all parts 2, 3, 4, 5 on the chassis reduces the shear forces between the parts due to vibrations, which in turn makes it less essential that the parts be displaceable in relation to one another. There is consequently increased scope for fixing parts of the air conditioning system essentially rigidly to one another by means of the pipelines 6, 7, 8, 9, which in turn means that rigid materials can be used as pipelines, which provide a seal against the leakage of refrigerant out into the surroundings and against moisture getting into the system. If rigid pipelines are used, it may be necessary in certain cases to allow the connecting elements that join these to the parts 2, 3, 4, 5 of the system to have a certain flexibility in order to absorb the vibrations that are produced in the petrol or diesel-powered engine. Alternatively the entire system may be mounted on one and the same vibration-damping unit, which is in turn fixed to the chassis of the vehicle.

Claims: CLAIMS 1. Arrangement in an air conditioning system (1) intended for motor vehicles, especially passenger cars, and comprising a compressor (5), a condenser (2,) and an evaporator (3), which are connected by way of transfer elements (6, 7, 8, 9) in a closed circuit for the transfer of refrigerant, the condenser (2) and the evaporator (3) being arranged on the chassis of the vehicle, characterised in that the compressor (5) is mounted on the chassis of the vehicle. 2. Arrangement according to claim 1, characterised in that the transfer elements (6, 7, 8, 9) comprise rigid, jointless pipelines made, for example, of metal or plastic. 3. Arrangement according to either of the preceding claims, characterised in that the compressor (5), the condenser (2) and the evaporator (3) are located at a short distance from one another. 4. Arrangement according to any of the preceding claims, characterised in that the compressor (5) is driven by means of a motor (5a) intended solely for the compressor. 5. Arrangement according to claim 4, characterised in that the compressor (5) and the compressor motor (5a) form a combined unit. 6. Arrangement according to claim 4, characterised in that the compressor motor (5a) is adjustable and designed to control the output of the compressor (5) on the basis of the cooling requirement in the passenger compartment of the vehicle. 7. Arrangement according to claim 4, characterised in that the compressor motor (5a) is an electric motor. 8. Arrangement according to claim 1, 2 or 3, characterised in that the motor vehicle is an electric or hybrid vehicle and that the motor (5a) driving the compressor (5) is the vehicle drive motor.

Inventors: MAARDBERG BJOERN, MAARDBERG, BJOERN
Applicants: MAARDBERG BJOERN, VOLVO AB, AB VOLVO, MAARDBERG, BJOERN
Application year: 1999
Main classification: B60H1
IPC codes: B60H1