BACKGROUND TO THE INVENTION AND PRIOR ART

The invention relates to an arrangement and a method for cooling an area at the rear side of a vehicle engine below and/or at a rear side of a cab of a freight vehicle. The invention relates also to a computer programme and a computer programme product. Components situated below and/or at a lower rear side of a freight vehicle cab, e.g. gearbox and cab suspension, are often exposed to high temperatures from the vehicle's engine and as a result of conductive warming by the cooling air flow and radiation effects from warm components such as exhaust components. The problem is greatest at the locations where the vehicle has problems due to high component temperatures such that the ventilation of the engine space is insufficient. This often happens in situations where the vehicle is moving at low speeds, e.g. during reversing, when its speed is usually 60 km/h or less.

It is therefore desired to be able to cool the area behind the engine and portions of the vehicle's chassis which are close to the engine in order to prevent risk of the vehicle breaking down or of components disintegrating, but also to save costs by not having to use expensive high-temperature-resistant materials for such items as rubber and plastic parts, gaskets and electronic components. A way of solving the problem is described in SE532307 which refers to a device for cooling an area behind a vehicle engine below or at a rear side of a cab of a freight vehicle. According to that invention a duct is provided to lead outside air into the area behind the engine, which duct extends rearwards and inwards towards said area from an inlet aperture on a side of the vehicle.

The air intake referred to in SE532307 is situated in a cramped space which entails risk of damp and dust accumulating in the intake and makes installing the intake complicated. US5429411 refers to a roof air deflector comprising a plurality of bendable grilles for guiding the airflow, which air deflector is controlled either manually by the vehicle driver or automatically via vehicle-related functions such as brake pedal use.

US2009/0025994 refers to a wind-deflecting device situated between the cab and a superstructure/trailer, immediately above the engine space. The object of the device is to prevent downward airflows from reaching the engine space and thereby impairing the engine space cooling provided by inlet air from the radiator.

SUMMARY OF THE INVENTION

An air deflector situated on the roof of a freight vehicle cab is adapted, when in a first position, to directing the airflow across a cargo-carrying unit with which the vehicle is provided, e.g. a superstructure. The air deflector is regulatable between said first position and a second position in order to be able in said second position to direct the airflow down by means of a guide surface into a space between the cab's rear side and the cargo-carrying unit, towards areas in the space and/or below the cab where the temperature is high. At least one guide means is provided to guide substantially forwards in the vehicle's direction of movement the airflow directed towards the area of the rear side of the vehicle engine.

There is thus a need to cool components and areas of the vehicle, particularly at low vehicle speeds. Guide means and air deflectors are therefore used to move cold ambient air down to the engine space and/or the chassis and to cool components such as control electronics and sensitive plastic and rubber items in a cost-effective way. One object of the present invention is therefore to propose an arrangement and a method for cooling an area at the rear side of a vehicle engine below and/or at the rear side of a cab of a freight vehicle. The expression "rear side of a cab" also comprises exposed portions of the vehicle's chassis which are close to a vehicle engine.

A further object of the invention is to propose an arrangement which works on different truck models which are equipped with superstructures or trailers.

This object is achieved by the features indicated in the independent claims set out below. Other features and advantages of the invention are indicated by the dependent claims and the description set out below.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below by way of examples with reference to the attached drawings, in which

Fig. 1 depicts a vehicle cab and cargo-carrying arrangement provided with a first guide means, a second guide means, a third guide means and a fourth guide means,

Fig. 2a depicts a vehicle cab provided with a first guide means in a first position,

Fig. 2b depicts a vehicle cab provided with a first guide means in a second position, Fig. 3 depicts a vehicle cab provided with a first guide means according to an alternative embodiment, and

Fig. 4 is a flowchart illustrating the method according to the present invention. DETAILED DESCRIPTION OF EMBODIMENT EXAMPLE

The present invention will now be described with reference to the attached drawings, in which the same reference notations are used throughout to denote items which have the same or similar functions. Fig. 1 depicts a heavy vehicle in the form of a freight vehicle 1 with a cab 2 and an engine space 3. The cab is provided with a front portion 4, cab sides 5, a cab floor 6 and a rear side 36. The cab sides 5 extend towards a vehicle frame 9. The freight vehicle 1 is provided with steerable front wheels 7 and undepicted tractive rear wheels and is powered by a unit in the form of an engine 8 situated in the vehicle frame 9, which comprises two parallel elongate side members 10 connected to one another by a number of undepicted cross-members, in order to transmit its propulsive torque to the tractive wheels via an undepicted power train.

In a front hatch 11 situated in the front portion 4 there is at least one inlet aperture 12 intended to supply air to a cooling system 13. The cooling system 13 contains a circulating coolant which is circulated in an undepicted pipe system. The circulating coolant is arranged to cool the engine 8 and gives up its heat in a first radiator element 14 situated at a front portion 4 of the freight vehicle 1 . The diagram also shows a second cooling element 15 which may for example be a charge air cooler or an EGR cooler. The circulating coolant is cooled in the first radiator element 14 by surrounding air Q which flows in through the inlet aperture 12 and through passages in the second radiator element 15 and the first radiator element 14 before proceeding through the tunnel-like engine space 3, which the air thereafter leaves through an aperture at the rear edge of the engine tunnel 16.

Behind the cab 2 there is a cargo-carrying unit 17 which may take the form of a permanently fitted box, a trailer, a semitrailer or some other superstructure.

A first guide means 18, hereinafter called air deflector, is fitted on a roof 20 of the cab 2 and is regulatable between a first position and a second position. Fig. 1 and Fig. 2a depict the air deflector in the first position 18a in which an airflow Q1 is directed across the cargo-carrying unit 17. Fig. 2b depicts the air deflector in the second position 18b in which the airflow Q1 is directed down into a space 19 between the cab's rear side 36 and the cargo-carrying unit 17. ,-

The freight vehicle 1 depicted in Fig. 1 has at least cab control unit 21 , e.g. an electronic control unit (ECU). The cab control unit is adapted to receiving sensor signals from various parts and components of the vehicle and to delivering control signals in certain running conditions to switching means 22 which cause the air deflector 18 to move between the first position 18a and the second position 18b.

The cab control unit 21 is adapted to receiving sensor signals, e.g. concerning vehicle speed. A speed detection means 37, e.g. speed sensors, may in one embodiment be situated in the cab control unit 21.

Temperature detection means 26, 27, e.g. temperature sensors, are provided where high temperatures occur. In Fig. 1 they are strategically situated below the cargo- carrying unit 17 on the vehicle frame 9 and adjacent to the engine 8. Other locations are of course possible.

The switching means 22 is controlled by preprogrammed instructions in the cab control unit 21. The preprogrammed instructions typically take the form of a computer programme product 23 stored on a digital storage medium, e.g. a working memory, flash memory or a read-only memory, and are executed by the control unit 21. The vehicle's behaviour in a specific situation may be adapted by altering the preprogrammed instructions.

The cab control unit 21 is provided with a location determination means 43, e.g. a GPS receiver, which receives information from satellites via an antenna 24, calculates a location of the vehicle 1 and uses both to create a computerised version of the configuration of the itinerary. The cab control unit 21 is also adapted to receiving itinerary data from a topography read-off means 25, e.g. a camera or radar. A computerised version of the configuration of the itinerary, a read-off version of the itinerary or a combination of both may be used to obtain information, e.g. about the gradient of the road, and to determine whether there is or soon will be an increased cooling requirement, e.g. there may be problems due to high component

temperatures during reversing of the vehicle. Fig. 2a depicts schematically the air deflector 18 fitted on the roof 20 of the cab 2. The air deflector is regulated between the first position 18a and a second position 18b (depicted in Fig. 2b) by an actuating means 31. This actuating means 31 may for example be an air cylinder, a toothed rack or an electric motor. The actuating means 31 is connected to the switching means 22 either directly or via an undepicted activation means comprising an undepicted activation circuit, and is acted upon by control signals which the cab control unit 21 generates on the basis of information from speed detection means 37, temperature detection means 26, 27, topography read-off means 25 and/or location determination means 43. This information is represented in the diagram by the arrow 38. In an alternative embodiment the position of the air deflector is regulated manually by the driver, e.g. via a control in the cab (not depicted in the diagram).

As may be seen in Fig. 2a and Fig. 2b the air deflector 18 is provided with a forward link arm 32 and a rear link arm 33 (represented by broken lines in both drawings). The forward link arm 32 is arranged for pivoting relative to the roof 20 via a hinged fastening point 34, and the rear link arm 33 is arranged for pivoting at a separate fastening point 35 which is situated adjacent to the roof (not depicted in the diagram). The result is greater controllability in that the air deflector 18 can be adjusted both laterally and vertically by the actuating means 31 adjusting the forward link arm 32 and thereby also adjusting the rear link arm 33. In an alternative embodiment the forward link arm 32 and the rear link arm 33 are both arranged for pivoting relative to the roof 20 via the same hinged fastening point 34.

The actuating means 31 is connected to the forward link arm 32 or, not depicted in the diagram, adjacent to the fastening point 34 in order, when activated, to move the air deflector from the first position 18a to the second position 18b or back from the second position 18b to the first position 18a.

It may also be seen in the drawings that the air deflector 18 has an outer guide surface 41a for directing the airflow Q1 across the cargo-carrying unit 17 when the air deflector is in the first position 18a, and an inner guide surface 41 b for directing the airflow Q1 down into the space 19 between the cab's rear side 36 and the cargo- carrying unit 17 when the air deflector is in the second position 18. The embodiment described above is particularly suitable for use on vehicles with no cargo-carrying unit 17 or where the cargo-carrying unit 17 is so low as to not reach the same height as the air deflector 18. In such cases the air deflector 18 is required to direct the airflow Q1 down into the space 19. If on the contrary the vehicle is equipped with a cargo-carrying unit 17 which reaches at least the same height as the air deflector 18, it is possible to use the alternative embodiment illustrated in Fig. 3.

In this alternative embodiment, the air deflector 18, like that previously described, is arranged for pivoting between a first position 18a and a second position 18c which differs from the second position 18b in that the air deflector is so directed as to form between it and the cab roof 20 an air gap 39 through which the airflow Q1 can pass and impinge upon a forward surface of the cargo-carrying unit 17. This will result in a stagnation zone where the airflow Q1 meets the cargo-carrying unit 17, and in the airflow Q1 being directed down into the space 19. To facilitate this, a guide means 40 may create the air gap 39 by putting the air deflector into position 18c. The air deflector is activated in the same way as previously described. In an alternative embodiment a directing means 42 may be provided on the cargo-carrying unit 17 to direct the incoming airflow Q1 passing through the gap 39 in such a way that it is guided down into the space 19.

Fig. 1 schematically depicts second guide means 28, hereinafter called air deflector, which is fitted adjacent to the vehicle on the forward side of the cargo-carrying unit 17. The air deflector 28 may take the form of one or more platelike elements and may be static, i.e. not regulatable, and be adapted to guiding the airflow Q1 down into the space 19 between the cab's rear side 36 and the cargo-carrying unit 17 towards areas in the space 19 and/or below the cab 2 where the temperature is high. In an alternative embodiment the air deflector 28 is adjustable upwards and downwards in order to guide towards areas in the space 19 and/or below the cab 2 where the temperature is high the airflow Q1 which is directed downwards in the space 19 between the cab's rear side 36 and the cargo-carrying unit 17. An advantage of the air deflector 28 being adjustable is that the airflow Q1 can be guided towards different components and areas. Depending on where and how the vehicle is operating, variation of which components and areas need cooling is thus possible. The air deflector 28 is operated in suitable ways, e.g. by an electric motor (not depicted in the drawings) on the basis of control signals from the switching means 22. The air deflector 28 is with advantage as wide as the cargo-carrying unit 17 in order to achieve the most effective guidance possible of the airflow Q1.

Fig. 1 depicts a third guide means 29, hereinafter called air deflector, situated at the rear edge of the engine tunnel 16. The air deflector 29 may be static, i.e. not regulatable. In an alternative embodiment the air deflector 29 is regulatable and makes it possible, when in an angled position, for cooling air Q1 directed downwards into the space 19 to be guided in below the cab 2. The air deflector 29 may take the form of one or more platelike elements for guiding the air. The air deflector may also guide the airflow Q which flows in through the inlet aperture 12 in order to cool warm areas in the space 19. The air deflector 29 has a certain width to make it possible to direct the airflow, its magnitude being limited only by the geometry of the

space/components surrounding the air deflector. The air deflector 29 can be adjusted upwards and downwards in order to guide the airflows Q1 and Q. It may for example be fitted on the rear cab bracket which is fastened to the frame members (not depicted in the drawings). The air deflector 29 is operated in a suitable way, e.g. by an electric motor (not depicted in the drawings) on the basis of control signals from the switching means 22.

Fig. 1 depicts a fourth guide means 30, hereinafter called air deflector, situated in the cab floor 6. The air deflector 30 may be static, i.e. not regulatable. In an alternative embodiment the air deflector 30 is regulatable and is operated via the cab control unit 21 depicted in Fig. 1. The air deflector 30 may take the form of one or more platelike elements. The air deflector 30 is adapted to guiding the cooling airflow Q coming in from the inlet aperture 12, but also to guiding the incoming airflow Q1 from the space at the rear edge of the engine tunnel 16. The air deflector 30 causes the cooling airflow Q coming in from the inlet aperture 12 to be directed somewhat downwards, causing the creation of two zones, one of them with high pressure in front of the air deflector 30, the other with low pressure behind the air deflector 30. This low pressure causes the warm air to be sucked out, making it easier for the cooling air to enter the space round the engine 8 and reach the space at the rear edge of the engine tunnel 16. The air deflector 30 has a certain width to make it possible to direct the airflow, its magnitude being limited only by the geometry of the space/components surrounding the air deflector 30. The air deflector 30 may be put into different positions depending on the directions of the airflows Q and Q1. The air deflector 30 is operated in a suitable way, e.g. by an electric motor (not depicted in the drawings) on the basis of control signals from the switching means 22. The air deflectors 18, 28, 29 and 30 may be operated individually on the basis of the temperatures registered by the temperature detection means 26, 27. The cooling may be focused on the lower portion of the space 19, the area below the cab 2, the forward area below the cargo-carrying unit 17 or a combination of these areas. The cab control unit 21 may also do an analysis in case a maximum permissible temperature T _max will be reached, preferably by extrapolation of measured

temperature values. The cab control unit 21 may thus prepare for the process of adjusting the air deflectors 18, 28, 29 and 30. In another embodiment the positions of the air deflectors are regulated on the basis of information from sensor signals concerning the vehicle's speed and/or itinerary. The air deflectors 18, 28, 29 and 30 may be activated in conjunction, but also individually depending on which area needs cooling. At least one of the air deflectors 18, 28, 29 and/or 30 is thus adapted to guiding substantially forwards in the vehicle's direction of movement the airflow directed towards the area of the rear side of the vehicle engine.

Fig. 4 is a flowchart showing steps A-D which are performed in order to direct the airflows Q and Q1 to where cooling is needed.

When the vehicle is moving at low speeds, e.g. when reversing, there is risk of problems due to high component temperatures. A first step A depicted in Fig. 4 determines whether there is or will be an increased cooling requirement. The cab control unit 21 receives sensor signals from various parts and components with a view to delivering control signals to the switching means 22. In one embodiment data about the road ahead of the vehicle are used to determine whether there are or will be increased cooling requirements. In particular, a computerised version of the configuration of the itinerary or data from a topography read-off means 25 may be used. In another embodiment component temperatures are determined via temperature detection means 26, 27. If the temperature T is above a maximum level Tmax. the air deflectors are activated to guide the airflows Q and Q1. In a further embodiment the air deflectors are activated if the vehicle's speed V is below a highest speed V _max . The speed V _max must not be so high that the air deflectors might be exposed to excessive forces and the fuel consumption might increase. It is important that the determination of increased cooling requirements takes place in good time before the temperatures become too high . A combination of the above criteria for determining whether there will be increased cooling requirements may also be employed.

As a step B, when it is determined that there is or will be an increased cooling requirement the switching means 22 is acted upon by a control signal from at least one control unit 21 , thereby activating the air deflectors 18, 28, 29 and 30. They may be activated in conjunction, individually or in combinations. Activating said air deflectors and angling them to guide the airflows Q and Q1 will result in better cooling of exposed components and exposed areas, e.g. below the cab 2.

As a step C there is thereafter continuous monitoring of whether there still are cooling requirements. For example, control signals from the cab control unit 21 may be used to determine that there will be an increased cooling requirement. In one embodiment the air deflector 18 is adjusted progressively depending on temperature T and vehicle speed V, and the control unit 21 monitors temperature and speed levels. If the temperature drops and/or the speed increases, the air deflector 18 will sink progressively back to a first position 18a. At for example a speed of 60 km/h, the air deflector 18 is angled at a maximum aperture of 15 degrees, at 65 km/h a maximum aperture angle of 10 degrees is allowed and at 70 km/h a maximum angle of 5 degrees. The angles referred to in these examples are measured between the cab roof 20 and the forward link arm 32 in an angled position.

If at step B it is determined that there are no longer any increased cooling

requirements, said air deflectors are deactivated at a step D, otherwise the vehicle 1 continues with air deflectors activated. The air deflectors 18, 28, 29 and 30 may be activated in conjunction but also individually, depending on which areas need cooling.

The invention relates also to a computer programme product comprising computer programme instructions for enabling a computer system to perform steps according to the method described above when the programme instructions are run on said computer system. In one embodiment the programme instructions are stored on a medium which can be read by a computer system.

The invention is of course in no way restricted to the embodiments described above, since numerous possibilities for modifications of them are likely to be obvious to one skilled in the art without deviating from the basic concept of the invention such as is defined in the attached claims.