1. Background

1.1 Technical field

The present invention relates to a method for cooling according to the introductory part of the attached claim 1.

The invention also relates to a device according to the introductory part of the attached claim 6.

1.2 State of the art

An extremely important design problem concerning motor vehicles, particularly heavy motor vehicles such as trucks, is the incorporation of a cooling system with sufficient cooling capacity. Large powers have to be cooled away at times of substantial or full power output and during braking with so-called retarders. For this reason, arrangements exist for restricting engine output or retarder braking effect when the coolant reaches too high a temperature. Such restriction is of course undesirable because it limits the use of the vehicle.

The object of the present invention is to increase current capacity for cooling a vehicle's coolant in order to reduce the need for restriction of engine output and braking effect. 2. Summary of the invention

The object as above is achieved by what is specified in the independent claims. Further advantages are achieved by what is indicated in the respective dependent claims.

3. Brief description of the drawing

The invention is described below in more detail with reference to examples of embodiments and the attached drawing, in which

- Fig. 1 is a schematic diagram of two embodiments of a device according to the invention.

4. Detailed description of preferred embodiments

In Fig. 1, ref. 1 denotes a liquid-based cooling system for cooling at least the engine 2 of a motor vehicle. The cooling system may also be adapted to cooling other items of the vehicle, e.g. a so-called retarder for braking (not depicted) such as used inter alia on trucks. The coolant of the cooling system is intended to be cooled in a heat exchange element 3 by air, represented by arrows 4, in the vehicle's radiator 5 which is intended to have air passing through it.

Ref. 6 denotes the motor vehicle's cab, which is intended to be heated, when cab heating is needed, by air, represented by arrows 7, which air is intended to be heated by coolant in a separate cab heat exchange element 8 and to be supplied thereafter to the cab by a fan (not depicted). In a preferred version, the heat exchanger 9 of the cab heat exchange element 8 and the fan are arranged in a separate cooling configuration whereby the coolant is intended to be cooled by air, represented by broken arrows 10 and an angled arrow 11, which air is intended to be supplied thereafter to other spaces than the cab, the cab heat exchanger thus being used for cooling of coolant without the cab being warmed by the heated air.

According to a preferred embodiment, there are devices (not depicted), e.g. temperature detection means, a valve device and a control device for the latter, for initiating cooling of the coolant by the separate cooling configuration when the temperature of the coolant exceeds a predetermined level.

According to a likewise preferred embodiment, represented by the broken arrows 10, there are devices (not depicted) for reversing the fan of the cab heat exchange element, for use in the separate cooling configuration, without heated air being supplied to the cab. Embodiments are conceivable whereby the direction of rotation of the fan is reversed as compared with the usual direction but also whereby the fan blades are turned, with no change of direction of rotation, to drive air in the opposite direction to the usual one. Such a version draws air corresponding to the broken arrows 10 out of the cab.

According to a further preferred embodiment, represented by the angled arrow 11 , there is at least one separate air supply duct (not depicted) leading to a space other than the cab, for use in the separate cooling configuration. According to what in some cases is a preferred addition to this embodiment, there is an arrangement (not depicted) for supplying the cab with a preferably predetermined portion of the air heated by the separate cooling configuration. According to one version, said arrangement comprises damper devices (not depicted) adapted to separating a portion, for supply to the cab, of the heated air. The method and also the function of the device according to the invention are probably substantially indicated above. In the separate cooling configuration, the heat exchanger of the cab heat exchange element is thus used to supplement when necessary the ordinary cooling system, which cools at least the engine, by further cooling capacity irrespective of whether cab heating is desired or not.

The invention is described above with reference to examples of embodiments. More embodiments and also minor modifications and additions are of course conceivable without departing from the fundamental concept of the invention.

Thus embodiments are conceivable in which the separate cooling configuration comprises separate fan devices (not depicted), arranged for the purpose, for air cooling of coolant by the heat exchanger of the cab heat exchange element and for supplying the air thus heated to spaces other than the cab. It is also conceivable for such fan devices to be used in combination with the fan of the cab heat exchange element.

The version with separate fan devices is particularly suitable for being combined with at least one separate air supply duct.

The invention is thus is not to be regarded as limited to the embodiments indicated above, but may be varied within its scope indicated by the attached claims.