FIELD OF THE INVENTION The present invention relates to the field of utility vehicles. Especially, the invention relates to air flow for cooling of a casing housing the propulsion motor of an articulated drive utility vehicle.

BACKGROUND OF THE INVENTION

Utility vehicles for outdoor use are used for various purposes. Often such vehicles are propelled by a combustion engine arranged in a casing, and a fan driven flow of air through a liquid radiator is normally used to liquid cool the engine, such as known from cars.

However, cooling of such engine may be challenging if the vehicles is expected to operate at high temperatures and at the same time at places with dust and dirt, e.g. with dry leaves etc. Here, the required fan driven air flow through the radiator may be so high that dirt is sucked into the air inlet, e.g. finally blocking the air inlet. This may especially be the case, if the vehicle is expected to have compact dimension, leaving only a limited space available within the casing housing the propulsion motor and e.g. other equipment to be cooled too.

SUMMARY OF THE INVENTION

Thus, according to the above description, there is a need for a solution to effectively cool a propulsion motor casing of a utilty vehicle to provide an effective cooling with a limited air flow. In a first aspect, the invention provides an articulated drive utility vehicle for outdoor use, the vehicle comprising a front part with driver controls, and a rear part connected to the front part by an articulated drive,

wherein the front or rear part comprises a casing for housing :

- a propulsion motor of the vehicle,

- a liquid radiator, and - a motorized rotor fan with a plurality of blades, and

wherein the fan is positioned so as to provide flow of air through the radiator from an inlet to an outlet via at least an airtight or substantially airtight part of the casing.

Such utility vehicle is advantageous, since utilizing an airtight part of the propulsion motor casing for providing the air flow through the radiator, a compact and yet efficient air flow can be provided, where the fan and the radiator are spatially separated. E.g. the fan can be placed in a rear part of the casing, while the radiator is placed at the front part of the casing, where the casing in-between is made airtight or at least substantially airtight. Hereby space is saved, since the casing wall is utilized as air flow passage for the air flow driven by the fan, through the radiator. Since the full dimension of the casing can be used for the air flow path, the air flow speed can be limited, and yet an efficient clooing of the liquid in the radiator as well as an efficient cooling of the inside of the casing can be obtained.

Compared to a radiator and fan setup as known from a car, where a circular fan is placed behind adjacent to a rectangular shaped radiator, the configuration proposed according to the invention, a better utilization of the radiator can be obtained. "Dead spots" with inadequate air flow in the corners of the radiator can be eliminated or at least significantly reduced by utilizing an airtight part of the casing for guiding the air flow betweel fan and radiator. This helps to utilize the radiator more effectively, and thus at the same cooling degree, a lower air flow can be used.

One fan can be used to cool multiple radtiators, thereby increasing cooling capacity with one fan. A double cooling of the propulsion motor is possible, i.e. via the radiator and if the fan is placed so as to drag air through said part of the casing, if the motor is placed inside this part of the casing, thereby allowing cooling of hydraulic oil equipment equipment. Since air can be dragged through the casing, only rather few openings in the casing are necessary, which helps to protect equiepement inside the casing.

The invention helps to ensure a low noise level from the vehicle, since a large fan with a low speed, and thereby low noise, can be selected. I.e. the fan blades can be larger in size than the size of the radiator, which will normally limit the fan blade dimensions.

The invention allows an advantageous way of controlling speed of the fan. Instead of temperature of the liquid through the radiator, e.g. engine cooling water temperature, a temperature sensor in the casing can be used to control the fan speed.

By 'airtight' part of the casing is understood a part of the casing which can be considered airtight with respect to the air flow driven by the fan through the radiator. Especially, the casing should be so tight that the fan is preferably be able to generate a pressure of at least 0.1 bar compared to the surroundings, so as to force air through the radiator. In the following, preferred features and embodiments will be described.

In one embodiment, the fan may be positioned at a rear part of the casing, e.g combined with the radiator being positioned at a front part of the casing. Hereby, the full length of the casing is preferably airtight and serves as air flow guide, and hereby the air flow will serve to cool the propulsion motor surface as well as other equipment which may be positioned inside the casing and which may also need air cooling.

In general, several configurations of fan and radiator positions may be envisaged within the scope of the invention. E.g. the radiator may alternatively to the front position be positioned at a rear part of the casing. The fan may be positioned at a bottom part of the casing, at a top part of the casing, or at a middle part of the casing. It is to be understood that the radiator may be split into two or more separate parts which can be positioned differently inside and/or at a surface part of the casing. Further, the fan may be split into two or more fan units positioned differently inside of at different surface parts of the casing.

The fan may be positioned at a bottom part of the casing, at a top part of the casing, or in a middle part of the casing.

To allow double cooling of the propulsion motor, the propulsion motor may be positioned in said airtight part of the casing. At least one element to be cooled by air, apart from the propulsion motor, may further be positioned inside said airtight part of the casing.

The radiator comprises at least one radiator part arranged to transport liquid serving to cool the propulsion motor of the vehicle, such as the propulsion motor comprising a combustion engine being cooled by said liquid.

The radiator may comprise a radiator part arranged to transport liquid for air conditioning, such as for air conditioning serving to provide cool air conditioned air to the driver cabin.

The radiator may be arranged at the inlet or the outlet of the airtight part of the casing. Alternatively or additionally, the radiator is arranged at a bottom part or a top part of the casing. The radiator may be arranged at a front part or a rear part of the casing, and/or the radiator may be arranged at a side part of the casing.

The fan may be arranged at the inlet or the outlet of the airtight part of the casing. Alternatively or additionally, the fan may be arranged at a bottom part or a top part of the casing. The fan may be arranged at a front part or a rear part of the casing, and/or the fan may be arranged at a side part of the casing.

Especially, the vehicle may comprise two fans arranged at respective positions inside or at an inlet or outlet of the casing. In preferred embodiments, the fan is positioned so in relation to the radiator, so that air flow between fan and radiator passes at least a length of 20 cm of the airtight part of the casing. E.g. the air flow may pass at least a length of 50 cm, or 100 cm or even more, depending on the overall dimensions of the casing.

Especially, the casing may be box shaped or at least substantially box shaped. The casing may be formed by a wall of a polymeric material, a metal, or wood, or the like, which can be formed airtight or substantially airtight. Preferably, the propulsion motor, e.g. a combustion engine, is positioned in said airtight part of the casing. Further, preferably at least one element to be cooled by air, apart from the propulsion motor, is positioned inside said airtight part of the casing. Hereby the air flow driven through the airtight part of the casing can be used to cool additional equipment, e.g. machinery, inside the casing.

Preferably, the radiator comprises a radiator part arranged to transport liquid serving to cool the propulsion motor of the vehicle, such as the propulsion motor comprising a combustion engine being cooled by said liquid. The radiator may alternatively or additionally comprise a radiator part arranged to transport liquid for air conditioning. Hereby, one single fan may be used to drive air flow for the function of both providing air flow through the radiator for cooling the propulsion motor and e.g. serving to provide air conditioning of the driver's cabin.

The propulsion motor may comprise a combustion engine, and/or an electric motor, such as the propulsion motor being one single electric motor.

A control unit may be arranged to control the fan. Especially, the control unit may be arranged to control a direction of rotation of the fan, so as to enable the fan to provide flow of air from the outlet to the inlet. Such reversing of air flow allows the fan to blow off any dirt or other material being stuch to the inlet louver.

Especially, the control unit may be connected to a vacuum or pressure sensor arranged to sense a pressure in the airtight part of the casing, and wherein the control unit is arranged to reverse a direction of rotation of the fan in response thereto, such as to reverse a direction of rotation of the fan if said pressure exceeds a predetermined threshold value. This allows an automated air flow reversing function to blow off any material stuck to the inlet louver, if it is sensed that the natural air flow is hindered. The control unit may be arranged to control a rotation speed of the fan in response to an input from a temperature sensor, such as a temperature sensor arranged to sense a temperature in the airtight part of the casing, such as a temperature sensor arranged to sense a temperature of liquid transported through the radiator. Hereby, it is possible to control the fan speed to keep the tempature inside the casing to be within a limited temperature interval. Further, a reduction of external noise from the vehicle is possible, since the speed of the fan can be reduced to a minimum to keep down the temperature at a desired level. The control unit may be arranged to adjust an angle of the blades of the fan, such as to adjust an angle of the blades of the fan so as to control an air flow speed in response to an input from a temperature sensor, such as a temperature sensor arranged to sense a temperature in the airtight part of the casing, such as a temperature sensor arranged to sense a temperature of liquid transported through the radiator. This can be used to control the air flow driven by the fan as an alternative or in addition to control of fan rotation speed.

The control unit may be arranged to adjust an angle of the blades of the fan, such as to adjust an angle of the blades of the fan so as to control an air flow speed in response to an input from a temperature sensor, such as a temperature sensor arranged to sense a temperature in the airtight part of the casing, such as a temperature sensor arranged to sense a temperature of liquid transported through the radiator. The vehicle may especially have a front part arranged with an interface arranged for mounting of a variety of different tools, e.g. a broom or brush, a shovel, a spray boom, a vacuum cleaner, a snow scraper or the like. However, the utility vehicle may alternatively have a dedicated tool mounted, or the utility vehicle is arranged. The vehicle is preferably a 4-wheel vehicle, two wheels at the front part, and two propulsion wheels at the rear part, driven by the propulsion motor.

In special embodiments, the vehicle has a total length of 1.5 to 6 m. However, it is to be understood that it can be longer or shorter, if preferred. BRIEF DESCRIPTION OF THE FIGURES

The invention will now be described in more detail with regard to the

accompanying figures of which

Fig. 1 shows a sketch of an articulated utility vehicle embodiment with a front part with a driver's cabin, and a rear part with a casing for housing the propulsion motor and other equipment, Fig. 2 illustrates one possible configuration of fan and radiator relative to each other with utilizing an intermediate airtight casing part airflow (indicated by arrows),

Figs. 3-7 illustrate sketches of various possible fan and radiator configurations, and

Figs. 8a-8c illustrate drawings of radiator and fan arrangements for a specific embodiment of a utility vehicle casing. DETAILED DESCRIPTION OF EMBODIMENTS

Fig. 1 shows a basic sketch of an articulated vehicle embodiment having a front part FP with one set of wheels and with driver controls in a driver cabin. A rear part RP with one set of wheels is connected to the front part FP by an articulated drive ADR. In this embodiment the rear part RP has a casing CS for housing a propulsion motor of the vehicle, e.g. a combustion engine or an electric motor, or both. Further the casing houses a liquid radiator with one or more radiator elements, and one or more motorized rotor fans each with a plurality of blades. The radiator and the fan are arranged so as to drive air from an inlet of the casing CS to an outlet of the casing CS in order to cool or heat liquid in the radiator.

Fig. 2 serves to illustrate the principles of the invention by a simple top view sketch of an embodiment of the casing CS with a radiator R and a fan F arranged at the air inlet I and air outlet O, respectively. The fan F serves to produce a vacuum inside a substantially airtight part of the casing CS, here illustrated as the entire length L of the casing CS, since the radiator R and fan F are positioned at respective ends of the casing CS. In the shown embodiment, the propulsion motor MT is positioned inside the airtight part of the casing CS. Especially, the motor MT may be a combustion engine which is cooled by liquid forced to flow through the radiator R. Alterantively, or additionally, the radiator R may comprise one or more elements with a separate liquid circuit serving to provide air conditioning, e.g. air conditioning of the driver cabin.

Arrows serve to illustrate air flow from inlet I at the front of the casing CS, through the radiator R, through the airtight part L of the casing CS, thereby passing the propulsion motor MT thus cooling the motor MT, and finally via the fan F to the outlet O of the casing CS at the rear of the casing. The fan F is shown here to have blades dimensioned to substantially fill the space provided by the cross sectional are of the rear part of the casing CS, thereby allowing large blades to be used, which helps to reduce external fan noise.

As already mentioned, by 'airtight' is merely understood that the casing should be tight enough to allow the fan F to produce a vacuum of 0.1 bar relative to the surroundings, however preferably more, but this allows for assembly of the various elements forming the casing CS without airtight sealings. Thus, the sides, bottom and top part of the casing CS can be formed by plates of one single layer without the need for a specific sealing. Thus, especially the outer plates of the casing can serve to form the airtight part of the casing. In Fig. 2, the casing CS is rectangular in shaped, however it is to be understood that various shapes can be used as alternatives, if preferred.

Figs. 3-7 show various embodiments, where the fan and radiator can be positioned differently in relation to the casing CS, relative to each other and relative to air inlet and air outlet of the casing CS. The same radiator and fan symbols as in Fig. 2 are used.

Fig. 3 shows an inlet I at the front, where the radiator is positioned. The outlet O is at the rear. The fan is located inside the casing with only a limited length L of the casing serving as airtight part generating a vacuum to drive air through the radiator. Fig. 4, as in Fig. 3, has the radiator at the inlet I at the front, while two fans are placed at respective outlets O at rear parts on the sides of the casing. Thus, here the major part of the casing serves as airtight chamber for driving air through the radiator.

Fig. 5 shows an inlet I at the front, where the fan is positioned. Outlet O is at the rear of the casing, where the raditator is positioned. Thus, as in Fig. 2 the entire casing length serves as airtight chamber. Fig. 6 shows and inlet I, as in Fig. 5, with the fan at the front, while separate radiator elements are positioned at respective side outlets O.

Fig. 7 shows a casing with the radiator R positioned at an inlet at the top of the casing, while the fan is positioned at an outlet at the bottom part of the casing.

It is to be understood that numerouos other fan/radiator inlet/outlet

configurations can be used.

Figs. 8a-8c show drawings of a specific outdoor utility vehicles rear part in a side view, a cut away side view, and a cut away top view. The air inlet is at the front, i.e. the one facing the front part (not shown) of the vehicle. The front has an inlet with two radiator elements R positioned immediately behind inlet louvers. The two radiator elements R are angled so that their inlet surfaces face in an angle of such as 30°-60° with a front direction. Hereby the total radiator R area is larger than a cross sectional area of the casing of the rear part. Inside the casing a combustion engine MT is positioned, and the motorized fan F is positioned immediately behind an outlet louver at the rear of the casing. The combustion engine MT is liquid cooled by liquid forced through at least one of the two radiators R, e.g. both, or only one, while the other one serves for air conditioning.

Only one single fan F is used to drive air through two radiator R elements, which would normally required respective fans. Further, the engine MT and e.g. other equipment inside the casing is cooled by air driven through the compartment inside the casing. To sum up, the invention provides an articulated drive utility vehicle for outdoor use. The vehicle has a front part with driver controls, and a rear part with a casing for housing a propulsion motor of the vehicle. A motorized rotor fan with a plurality of blades is arranged within the casing, and wherein the fan is positioned so as to provide flow of air through a liquid radiator from an inlet to an outlet via at least an airtight part of the casing. In this way, the casing serves to provide part of the air flow path, and the fan and radiator can be spatially separated. Hereby, it is possible to reduce air flow speed and still provide effective cooling of the radiator. Especially, the radiator can be placed at a front part of the casing, while the fan can be placed at a rear part of the casing. However, a large variety of configurations of the fan and radiator relative to the casing are possible.

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is to be interpreted in the light of the accompanying claim set. In the context of the claims, the terms "including" or "includes" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.