"CONDITIONING BOX FOR A WORK VEHICLE"

The present invention concerns a conditioning box for a work vehicle, in particular a conditioning box for a work vehicles such as equipment construction vehicles.

All vehicles comprise at least a hydraulic circuit for conditioning an operative fluid of a hydraulic circuit of a specific device of the vehicle, such as the operative fluid of AC circuit or the operative fluid of the engine cooling circuit of the vehicle.

Work vehicles comprises usually more circuits using an operative fluid than a passenger vehicle because of the utilities whose they are provided. For sake of example it may be needed to condition the oil of power oil circuits or the operative fluid of an intercooler.

In view of the above, for optimizing the conditioning of the operative fluids the heat exchangers of work vehicle is known to use a conditioning box defining a closed shape having a plurality of faces on which at least one heat exchanger may be fixed. Usually, such conditioning box is placed in front of the motor of the vehicle and is known as "cooling box".

The conditioning box comprises moreover a single opening by which air is pumped or sucked thanks to a single fan which is hydraulically operated. The air may pass through the heat exchangers that are fixed on the faces of the conditioning box .

However, in order to guarantee a sufficient air flow in the heat exchangers, such single hydraulic fan has a considerable diameter. In fact, since the operation of the fan is hydraulic, high velocities cannot be easily reached and therefore the simplest way to increase the air flow generated by the fan is to increase its diameter.

However the air flow given by a fan follows the equation:

0 = k _* n _* d ³

where k is a coefficient, n is the number of round of the fan and D is its diameter.

In contrast, power absorbed by a fan follows the equation :

P = k' * n ³ * d ⁵

where k' is a coefficient, n is the number of round of the fan and D is its diameter. In view of the above, it is clear that increasing the diameter of the fan costs great power absorption; in fact by increasing the diameter of the fan, the power absorbed by this latter increases squarely.

Moreover, by using a single fan, the air flow is equal for each heat exchanger. Therefore, for example, if an heat exchanger needs the maximum of the air flow and the others heat exchanger do not need such a maximum flow, they are in any case subject to this latter. In this way the temperatures of fluids flowing in the heat exchangers cannot be optimized contemporarily for each heat exchanger.

Therefore, the need is felt to improve the efficiency of conditioning box for vehicles, in particular work vehicles, while improving the usability and versatility of such conditioning box.

An aim of the present invention is to satisfy the above mentioned need in an optimal and economic way.

The aforementioned aim is reached by a conditioning box and to a method for controlling such conditioning box as claimed in the appended set of claims.

For a better understanding of the present invention, a preferred embodiment is described in the following, by way of a non-limiting example, with reference to the attached drawings wherein:

• Figure 1 is a perspective view of a vehicle comprising a conditioning box according to the present invention;

• Figure 2 is a perspective view a conditioning box according to the present invention;

• Figures 3 and 4 are respective exploded views of the conditioning box of figure 2;

• Figures 5, 6, 7a, 8 and 9 are perspective views of different operative conditions of conditioning box of figure 2; and

• Figure 7b is a graphic showing a fan velocity, in rounds per minute, in function of the air flow, in m ³ , passing through a fan according to the operation of figure 7a.

Figure 1 discloses a work vehicle 10, e.g. in the described case an wheel loader, essentially comprising a body 10a defining a cabin 10b for accommodating the user, two pair of wheels 10c on which the body 10a is supported and at least one operating device lOd, e.g. a grab.

Vehicle 10 moreover comprises, preferably placed in a rear portion of the body 10a, a conditioning box 1 configured to allow the conditioning of operative fluids of work vehicle 10 as described hereinafter in greater detail. Preferably, conditioning box 1 is positioned to be in front of a motor of the vehicle.

Making reference to figures 2-4, conditioning box 1 may comprise a structure 2 comprising a plurality of uprights 3 connected together to define a closed shape. More preferably uprights 3 of structure 2 are realized as one piece, e.g. by casting. Preferably structure 2 may comprise twelve uprights 3 defining a parallelepiped, preferably a cube, and therefore defining six faces, i.e. a bottom and a top face, a right and left lateral faces and a front and rear lateral faces .

For sake of clarity, the above terms "left", "right", "bottom", "top", "front" and "rear" are non-limitative and are referred to the representation of figure 2 and the subsequent figures representing cooling box 1 ; moreover, the aforementioned faces are only a geometrical reference since structure 2 is simply defined by the presence of uprights 3 connected together (i.e. faces are not plates).

Conditioning box 1 further comprises fixation means 4 configured to allow the fixation of the structure on the work machine. For example, as shown, fixation means 4 may comprise two brackets 5 fixed to the bottom face of the structure by which this latter may be fixed to work machine 10.

Conditioning box 1 may comprise coupling means 7 configured to couple at least one heat exchanger in at most all but one of the faces defined by themselves. In particular coupling means 7 may be threaded fasteners configured to be insert respective holes (not shown) realized in uprights 3.

In particular, an heat exchanger 11 of the conditioning fluid of engine radiator circuit of the wheel loader 10 may be coupled on the uprights 3 which define left lateral face, an heat exchanger 12 of the oil of transmission circuit and/or other hydraulic circuits of wheel loader 10 may be coupled on the uprights 3 which define right lateral face, an heat exchanger 13 of the conditioning fluid of intercooler circuit and a heat exchanger 14 of the conditioning fluid of a condenser of the AC system of the wheel loader 10 may be coupled on the uprights 3 which define top face.

According to the above described embodiment, conditioning box 1 may further comprise plates 15, 16 which may be coupled on the uprights 3 which define respectively rear and bottom faces, in particular so that such plates 15 and 16 that may occupy all the space defined by aforementioned uprights 3.

As state above, structure 2 defines a closed shape, i.e. structure 2 define an inner volume 20 in particular externally delimited by uprights 3.

Conditioning box 1 advantageously comprises a main opening 21 located on front face of structure 2. In particular opening 20 occupies all the space of front face between the uprights 3. Opening 21 is configured to allow a fluidic communication between internal volume 20 and the environment. Advantageously opening 21 is placed in front of the motor of the vehicle. However, it is clear that conditioning box 1 may be housed anywhere with respect to the vehicle.

At least plate 16 may optionally be provided with a grid configured to increase the fluidic communication between internal volume 20 and the environment.

According to the invention, conditioning box 1 further comprises, for each heat exchanger 11, 12, 13 and 14 at least one fan configured to force air passing through the respective heat exchanger 11, 12, 13 and 14 and said opening 21 via inner volume 20.

In particular, the at least one fan is placed inside volume 20 and is fixed to structure 2 in front of the respective heat exchanger 11, 12, 13 and 14. Preferably, the at least one fan of two different heat exchangers 11, 12, 13 and 14 are fixed on different faces of cooling box 1; more preferably such faces are opposite with respect to each other .

Preferably the at least one fan is an electric fan and the at least one fan of the respective heat exchangers 11, 12, 13 and 14 may be controlled singularly. The at least one fan, being electric, may be operated as sucking or venting fan, simply by inverting the polarity of the power supply.

Cooling box 1 may comprise connection means (not shown) configured to connect a control unit to the at least one fan and detection means (not shown) configured to detect at least one operative condition of the fluid flowing in the heat exchangers 11, 12, 13 and 14 and/or environment temperature. Such control unit is provided with elaboration means configured to elaborate the information detected by detection means and to operate the fan according to the method described below in greater detail. Preferably control unit is a ECU of the vehicle.

According to the described embodiment, four fans 25 may be placed in front of the heat exchanger 11; preferably fans 25 are placed squarely around the center of the heat exchanger 11 and therefore comprises two upper fans 25a, 25b and two lower fans 25c, 25d.

Further, four fans 26 may be placed in front of the heat exchanger 12; preferably fans 26 are placed squarely around the center of the heat exchanger 12 and therefore comprises two upper fans 26a, 26b and two lower fans 26c, 26d .

With regard to heat exchangers 13 and 14, only a respective single fan 27, 28 may be placed.

Advantageously fans 25, 26, 27, 28 comprise respective supports 30 configured to allow the fixation of fans 25, 26,

27, 28 on structure 2.

Conditioning box may further comprise an oil tank (not shown), housed in the inner volume 20, and configured to collect oil from hydraulics circuits of the vehicle. This oil may be conditioned thanks to the air flow passing in inner volume 20 through the respective heat exchanger 11, 12, 13 and 14 and opening 21. A related pump may be used to make the oil circulate within the tank.

Conditioning box 1 may further comprise a cover 32 configured to protect structure 2 and the attached elements such as heat exchangers 11, 12, 13 and 14 and fans 25, 26, 27, 28 from the environment and to simultaneously allow the passage of air through heat exchangers 11, 12, 13 and 14.

In particular, cover 32 may comprise a plurality of walls 33 connected together and configured to protect at most each of the faces defined by structure 2. According to the embodiment described above, cover 32 may comprise three walls 33 for covering upper, left and right faces.

Each walls 33 comprises aeration means 34 configured to allow the passage of air through the covered heat exchanger. In particular aeration means 34 may be realized as loopholes 35 placed together to define at least one aeration grid 36 which may extend up to the entire surface area of wall 33.

The operation of the conditioning box 1 described above is the following, assuming that opening 21 is placed in front of the motor of the vehicle. Therefore the direction of flows of the air and "cold" and "warm" terminology are referred to this configuration in which a source of hot air is present in front of opening 21.

According to a first operative condition (shown in figure 5), i.e. a normal operation of the conditioning box, each fan 25, 26, 27, 28 is operated in order to generate an air flow F _ί=1;4 through the respective heat exchanger 11, 12, 13 and 14. In particular air flows F _ί=1;4 are directed from the environment to the inner volume 20 through the respective heat exchanger 11, 12, 13 and 14 and are fed thanks to opening 21 by which a compensative flow F may enter from environment to inner volume 20.

According to the above described operation, each fan 25, 26, 27, 28 may be separately regulated to guarantee a sufficient air flow for each heat exchanger thanks to electronic control of the control unit. The air from inner volume 20 will further flow through the motor of the vehicle to decrease its temperature because, even if this air is hot, it is always colder than motor temperature and therefore it may cool this latter.

According to a second operative condition (shown in figure 6), i.e. a quick warm up condition for at least one heat exchanger, at least one fan among fans 25, 26, 27, 28 is stopped, e.g. fans 25. This condition may be useful in certain conditions in which it is necessary to quick warm up an operative fluid, such as in winter. According to the above, the fluid passing through the heat exchanger 11 is not conditioned by the air flow and therefore is warmed up each passage in heat exchanger 11 because of the absence of the air flow generated by fans 25.

According to a third operative condition (shown in figure 7a), i.e. a modulated conditioning operation for at least one heat exchanger, at least one of air flows F _ί=1;4 is modulated to vary the air flow passing through the heat exchanger along the length of the respective heat exchanger.

According to such operative condition, inlet (not shown) of heat exchanger 11 is provided in the top portion of the heat exchanger 11 with respect to plate 16 and outlet (not shown) of heat exchanger 11 is provided in bottom portion of heat exchanger 11 with respect to plate 16. Accordingly, the fluid flowing in exchanger 11 decreases its temperature from top portion (inlet) to bottom portion (outlet) during its passage into exchanger 11.

For example, making reference to fans 25 and heat exchanger 11, upper fans 25a, 25b may rotate at a greater velocity than lower fans 25c, 25d. Accordingly, the air flow F generated by upper fans 25a, 25b will be greater than air flow F ' generated by lower fans 25c, 25d.

Making reference to figure 7b, the graphic shows the fan speed, in round per minute, in function of the air flow, in m3. In particular, two functions are disclosed, left (continue line) one represents the control law of upper fans 25a, 25b, and right (dotted line) one represents the control law of lower fans 25c, 25d.

Thanks to such decoupling between upper fans 25a, 25b and lower fan 25c, 25d, it is possible to minimized power absorption of fans 25 when the thermal load of the heat exchanger 11 is reduced (i.e. is lower than 100%) . This is achieved by firstly reducing the velocity of lower fans and successively the velocity of upper fans. In this way, a "gradient" of heat transfer may be realized by varying the velocity of fans along the position of heat exchanger 11.

In particular, to maintain an high cooling efficiency, it is advantageous to start by decreasing lower fans 25c, 25d, which are placed in front of bottom portion of heat exchanger 11 i.e. where fluid has a lower temperature with respect to its portion, proportionally with decreasing of thermal load of heat exchanger 11. If such load continues to decrease, lower fans 25c, 25d may be stopped and the velocity of upper fans 25a, 25b will be decreased accordingly.

According to a fourth operative condition (shown in figure 8), i.e. a cleaning function of conditioning box 1, fans 25, 26, 27, 28 may, for a short interval of time, reverse their operation (i.e. switching from sucking to venting or vice versa) and therefore air flows F _ί=1;4 will all be directed from the inner volume 20 to the environment through the respective heat exchanger 11, 12, 13 and 14.

In view of the above, pressure is suddenly increased in inner volume 20 and the air is expelled from inner volume 20 to the environment through the respective heat exchanger 11, 12, 13 and 14. In this way, possible dirt elements housed inside volume 20, e.g. dust, may be expelled thanks to the dejecting air flow.

According to a fifth operative condition (shown in figure 9), i.e. a maximized cooling down operation, at least one fan among fans 25, 26, 27, 28, e.g. fans 25, is controlled to increase their speed up to reach their maximum speed while the remaining fans, e.g. fans 26, 27 and 28, reverse their operation from sucking to venting .

In this way, in particular overheated conditions of the operative fluid of a circuit, it is possible maximize the air flow passing through the heat exchanger 11 and therefore the conditioning of the fluid flowing inside this latter. This is achieved by maximizing velocity of fans 25 and by generating a "depression" in volume 21 thanks to the reverse operation of the remaining fans 26, 27 and 28.

The present invention is moreover directed to a method for controlling the at least one fan 25, 26, 27, 28 of conditioning box 1.

The aforementioned method comprises essentially the steps of: • detecting a condition of the at least one heat exchanger 11, 12, 13, 14 of the conditioning box 1;

• defining an equivalent air flow which has to pass through the at least one heat exchanger 11, 12, 13, 14 in order to reach a required conditioning of the fluid flowing out the at least one exchanger 11, 12, 13, 14; and

• controlling the at least one fan 25, 26, 27, 28 of the conditioning box 1 according to the defined equivalent air flow.

The above described steps may be realized in the control unit which, as aforesaid, comprises elaboration means configured to memorize and elaborate the information received by detection means according to the aforementioned steps of the control method so as to operate accordingly the at least one fan 25, 26, 27, 28.

In particular, the detected condition of the at least one heat exchanger 11, 12, 13, 14 may be acquired thanks to detections means. Such condition may be one among the temperature or the flow of fluid flowing in the at least one heat exchanger 11, 12, 13, 14, or an operative condition of the operative circuit to which the at least one exchanger 11, 12, 13, 14 is coupled and/or environment temperature.

Examples of such operative conditions may be the temperature of the coolant fluid of engine radiator, the oil temperature of transmission/ hydraulic circuits, the intake air temperature of the intercooler, the operation of AC system of the vehicle or the presence of dirty elements in volume 21 of cooling box 1.

The equivalent air flow is defined by knowing the above mentioned detected condition and setting a target value of temperature/flow of the operative fluid flowing out the at least one heat exchanger 11, 12, 13, 14, or by an operative condition of the operative circuit to which the at least one exchanger 11, 12, 13, 14 is coupled.

Knowing the conditions of fluid flowing in the heat exchanger, the environment temperature and the desired conditions of fluid flowing out and the typology of the heat exchanger, it is possible to mathematically determine (via conventional thermodynamic laws) an equivalent air flow which has to pass through the at least one exchanger 11, 12, 13, 14 so that the fluid output reaches the desired conditions .

It is clear that all the above described operative condition may be controlled via the above described method.

For example, citing maximized cooling down operation, the detected condition may be an overheating of one heat exchanger, the equivalent air flow therefore has to be increased. As described, such increased air flow may be generated by controlling fans 25, 26, 27 and 28 by maximizing velocity of at least one fan 25 and by generating a depression in volume 21 by reverting the operation of the remaining fans 26, 27 and 28.

Preferably, the required air flow may be calculated while minimizing the power absorption of the at least one fan 25, 26, 27, 28 of conditioning box 1.

For example, the at least one fan 25, 26, 27, 28 such minimizing power absorption may be calculated by knowing the number, diameter and maximum velocity reachable by each of the at least one fan 25, 26, 27, 28. In particular such minimization may be realized thanks to known mathematically minimization methods, e.g. minimum square methods.

In view of the foregoing, the advantages of a conditioning box 1 according to the invention are apparent.

Thanks to the presence of at least one fan for each heat exchanger of cooling box 1 and to the fact that each of said fans may be controlled singularly, the air flow may be efficiently optimized for each heat exchanger.

In view of the preceding, power needs of all fans summed together is lower than the power need of a single hydraulic fan. The power need may be up to 50% less with respect to previous known solutions.

Moreover, since fans are electric, their velocity may be regulated independently with respect to engine speed and they may be controlled easily via an electronic control unit; further their function, i.e. sucking or venting, may be changed quick and easily.

In view of the above and because fans 25, 26, 27, 28 are fixed to different faces of the cooling box 1, a lot of operating conditions may be defined, such as fast cooling, warm-up or cleaning of cooling box 1.

Thanks to the preferable presence of a plurality of fans for each heat exchanger, they may be controlled singularly to define a gradient of heat transfer along the heat exchanger by modulating the air flow generated by each fan .

It is clear that modifications can be made to the described conditioning box which do not extend beyond the scope of protection defined by the claims.

First, it is clear that conditioning box 1 may be placed anywhere in the vehicle 1 and therefore, since the source of hot air of the motor may not be present, the sucking or venting operation of fans 25, 26, 27, 28 may be reversed by consequence .

For example, fans 25, 26, 27, 28 may be placed externally with respect structure 2 and their venting may be simply inverted.

Moreover, fans 25, 26, 27, 28 may be each a hydraulic fan and the control may be realized hydraulically and separated by the engine, even if such control would be more expensive than the described electric one.

Control unit may be a dedicated control unit which is connected to the ECU of the vehicle and connection means may be of any typology, e.g. electrical connection such as electrical wires or wireless means.

Finally and obviously, the number, typology and shape of fans for each heat exchanger may be varied; similarly, typologies and positioning of heat exchangers in conditioning box 1.