Cooling circuit of a vehicule

Abstract

Cooling circuit (24) for a vehicle, in particular a motor vehicle, this circuit comprising a pump (26) having at least one rotor driven in rotation by a motor (33) and configured to force the circulation of coolant in the circuit, characterized in that said at least one rotor comprises at least one driving screw (28) driven by said motor, and at least one driven screw (30) driven by said at least one driving screw, the driving screw(s) and driven screw(s) being configured to force the circulation of coolant in the circuit.

Description

Technical field of the invention

[0001] The invention relates to the field of cooling circuits for vehicles, in particular automobiles. Technical background

[0002] Typically, a cooling circuit for a motor vehicle, such as that shown in Figure 1 , notably comprises at least one pump 12 ensuring the circulation of a cooling liquid, such as water, in the cooling circuit.

[0003] A cooling circuit may further comprise a coolant reservoir 10, a heat exchanger 14 and at least one element 16 to be cooled, such as a vehicle engine.

[0004] The element 16 is equipped with a temperature sensor 20 whose signals are transmitted to a unit 18 for controlling a proportional valve 22 making it possible to regulate the flow of coolant leaving the pump 12 and supplying the heat exchanger 14.

[0005] In the current technique, the pump 12 is a centrifugal pump, that is to say it is a pump whose rotor is formed by an impeller with blades configured to suck in liquid through the center and to discharge it through its periphery. The flow rate of coolant at the outlet of the pump depends on the rotation speed of the impeller but is not always constant and it is therefore necessary to associate with this type of pump the aforementioned proportional valve 22. Furthermore, there is a latency time between the stopping of a centrifugal pump and the cancellation of the flow rate at the outlet of the pump. In the case where the circuit includes other (auxiliary) pumps, these pumps would also be centrifugal pumps. A cooling circuit with a screw pump is shown by the document EP 2 336 590.

[0006] The present invention provides an improvement to this technology. Summary of the invention

[0007] The invention relates to a cooling circuit for a vehicle, according to claim 1.

[0008] One of the advantages of a screw pump is that it provides an output flow proportional to the engine rotation speed and that is cancelled as soon as the pump is stopped. When using a screw pump in a cooling circuit, it is therefore understandable that it would be possible to eliminate the proportional valve required when using a centrifugal pump. Furthermore, another advantage is linked to the small size of a screw pump compared to a centrifugal pump. The power of a screw pump can, for example, be optimized by adapting the length, diameter and / or number of screws, whereas the power of a centrifugal pump can be optimized only by the diameter and thickness of its impeller.It would also be advantageous to use screws in the pump that are not made of metal but rather made of plastic or composite material, in order to reduce the weight of the pump and facilitate the production of these screws, for example by injection molding.

[0009] The number of driving screws and driven screws is not limiting and is determined according to the needs in terms of flow rate at the pump outlet in particular.

[0010] The circuit may include one or more of the following features, taken in isolation from each other or in combination with each other: the circuit comprises a driving screw aligned with an axis of the motor, and one or more driven screws extending parallel to the driving screw and meshed with this driving screw, the circuit comprises two driving screws parallel to an axis of the motor and driven by the latter via a gear train, and driven screws extending parallel to the driving screws and meshed with these driving screws, the number of driving and driven screws of the pump is between 2 and 16;this number is however not limiting, the number of driving screws is for example between 1 and 4 and the number of driven screws is for example between 1 and 4 for each of the driving screws, the driving and driven screws are mounted and guided in rotation in cylindrical housings of the same fixed body of the pump, the fixed body is mounted at one end of the motor, the screws are made of plastic or composite material, the pump is fixed on a coolant tank, the circuit comprises a heat exchanger, at least one element to be cooled and a temperature sensor of this equipment, the circuit being devoid of a proportional valve and said pump being configured to be controlled by a control unit according to signals emitted by said temperature sensor. ;

[0011] The present invention also relates to a vehicle, in particular a motor vehicle, comprising at least one circuit as described above. Brief description of the figures

[0012] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: [ Fig. 1 ] there Figure 1 is a schematic view of a vehicle cooling circuit, [ Fig. 2 ] there Figure 2 is a schematic view of a cooling circuit of a vehicle, according to one embodiment of the invention, [ Fig. 3 ] there Figure 3 is a schematic perspective view of a coolant reservoir equipped with a screw pump, [ Fig. 4 ] there Figure 4 is a schematic exploded perspective view of a first embodiment of a screw pump, [ Fig. 5 ] there Figure 5 is a schematic exploded perspective view of a second embodiment of a screw pump, [ Fig. 6 ] there Figure 6is an exploded perspective schematic view of a third embodiment of a screw pump. Detailed description of the invention

[0013] There Figure 1 has been described in the above.

[0014] There Figure 2 illustrates a cooling circuit 24 within the meaning of the invention. This circuit 24 comprises at least one screw pump 26. The circuit 24 further comprises a reservoir 10 of coolant.

[0015] The screw pump 26 and the reservoir 10 may be two separate elements connected by at least one pipe, or they may be mounted on top of each other as in the example of the Figure 3 where the pump 26 is fixed directly to the tank 10.

[0016] It is understood that the pump 26 comprises an inlet 26a connected to the reservoir 10 or opening into this reservoir, and an outlet 26b.

[0017] The screw pump 26 is connected to a heat exchanger 14 and to an element 16 to be cooled. The outlet 26b of the pump 26 is connected to an inlet 14a of the exchanger 14, an outlet 14b of which is connected to an inlet 16a of the element 16. This element 16 comprises an outlet 16b connected to the inlet 26a of the pump 26 or to the reservoir 10.

[0018] The element 16 is equipped with a temperature sensor 20, the signals from which are transmitted to a unit 18 for controlling the screw pump 26 in order to regulate the flow of coolant leaving the pump 12 and supplying the heat exchanger 14.

[0019] A screw pump 26 includes at least one driving screw driven by a motor, and at least one driven screw driven by the driving screw(s), the driving and driven screws being configured to force circulation of coolant in the circuit.

[0020] THE figures 4 to 6illustrate examples of embodiments of a screw pump 26. In the embodiment of the Figure 4 , the pump 26 comprises a driving screw 28 and a driven screw 30. The driving screw 28 has an elongated shape and comprises one end connected to a drive shaft 32 of the motor 33, which is for example an electric motor.

[0021] The screw 28 comprises a helical thread which extends substantially over its entire length. The screw 28 is housed in a first central housing 34 of a cylindrical body 36 of the pump 26.

[0022] The driven screw 30 has an elongated shape and extends alongside the driving screw 28, parallel to it. The screw 30 comprises a helical thread which extends substantially over its entire length, and which is complementary to that of the screw 30 so that the screws are meshed and the screw 30 is driven in rotation by the screw 28 which is itself driven in rotation by the axis 32.

[0023] The screw 30 is housed in a second lateral housing 38 of the body 36. The housings 34, 38 communicate with each other, as illustrated in the drawing. The body 36 is fixed to one end of the motor 33, and comprises for example at one axial end an annular fixing flange 36a. In the embodiment of the Figure 5 , the pump 26 comprises a driving screw 28 and three driven screws 30. The driving screw 28 has an elongated shape and comprises one end connected to the drive shaft 32 of the motor. The screw 28 comprises a helical thread which extends substantially over its entire length. The screw 28 is housed in a first central housing 34 of a cylindrical body 36 of the pump 26.

[0024] The driven screws 30 each have an elongated shape and extend alongside the driving screw 28, parallel to it. They are regularly spaced from each other around the screw 28. Each screw 30 comprises a helical thread which extends substantially over its entire length, and which is complementary to that of the screw 30 so that the screws are meshed and each screw 30 is driven in rotation by the screw 28 which is itself driven in rotation by the axis 32.

[0025] The screws 30 are housed in lateral housings 38 of the body 36. The housings 34, 38 communicate with each other, as illustrated in the drawing. The body 36 is fixed in a shroud 40 which is fixed to one end of the motor. This shroud 40 defines the inlet 26a and the outlet 26b of the pump 36. In the embodiment of the Figure 6, the pump 26 comprises two driving screws 28 and two driven screws 30. Each driving screw 28 has an elongated shape and comprises a helical thread which extends substantially over its entire length. The driving screws 28 are arranged parallel and side by side, and housed in first housings 34 of the body 36.

[0026] Each screw 28 carries at one axial end a pinion 42. A toothed wheel 44 is arranged between the pinions 42 secured to the screws 28 and is meshed with the latter so as to form a gear train. The toothed wheel 44 is mounted on the drive shaft of the motor (not visible) and drives the screws 28 via the pinions 42.

[0027] The driven screws 30 each have an elongated shape and extend alongside the driving screws 28, parallel to the latter. The axes of rotation of the screws 28, 30 are parallel and located for example on four corners of a parallelepiped.

[0028] Each screw 30 comprises a helical thread which extends substantially over its entire length, and which is complementary to that of the screw 28 so that the screws are meshed and each screw 30 is driven in rotation by one of the screws 28.

[0029] The screws 30 are housed in lateral housings 38 of the body 36. The housings 34, 38 communicate with each other, as illustrated in the drawing. As in the previous embodiment, the body 36 is mounted in a cowling 38 which is fixed to one end of the motor. This cowling 36 defines the inlet and outlet 26b of the pump 36.

[0030] In the various embodiments described above, the screws 28, 30 are advantageously made of plastic or composite material. They are for example made by injection molding, which makes it possible to have screws of complex shape at a relatively limited cost.

[0031] The invention brings several advantages, including:the reduced cost of a screw pump, in particular through the use of injected plastic screws; a current consumption of the motor 33 which is proportional to the flow rate of the pump 26; which allows energy savings compared to a centrifugal pump when a low flow rate of liquid is required; the screw pump 26 makes it possible to stop the circulation of liquid in the circuit when the motor 33 is not operating; this can, for example, make it possible to eliminate a closing valve from the circuit of the prior art; the flow rate of the pump is directly proportional to the rotation speed of the motor; the pump can be directly controlled as a function of the temperature of the element to be cooled 16; the transfer of liquid can be done in both directions and is a function of the direction of rotation of the motor; whereas it can only pass in one direction in a centrifugal pump; the screw pump has better hydraulic efficiency;that is to say that the current consumption is lower for the same volume of liquid transferred; the screw pump makes it possible to obtain a higher pressure compared to a centrifugal pump, whatever the speed of its rotor; the screw pump provides a liquid flow rate at the outlet proportional to the rotation speed of the motor; there is no cavitation phenomenon in a screw pump; and the screw pump is relatively compact and easily integrated into a coolant tank.;

Claims

1. A cooling circuit (24) for a vehicle, in particular a motor vehicle, the circuit comprising a pump (26) comprising at least one rotor rotated by a motor (33) and configured to force coolant to circulate in the circuit, said at least one rotor comprising at least one drive screw (28) driven by said motor, and at least one driven screw (30) driven by said at least one drive screw, the drive and driven screw(s) being configured to force coolant to circulate in the circuit, characterized in that the drive and driven screws (28, 30) are made of plastic or composite material.

2. The circuit (24) according to claim 1, in which it comprises a drive screw (28) aligned with an axis (32) of the motor (33), and one or more driven screw(s) (30) extending parallel to the drive screw and meshing with this drive screw.

3. The circuit (24) according to claim 1, in which it comprises two drive screws (28) parallel to an axis (32) of the motor (33) and driven by the latter via a gear train (42, 44), and driven screws (30) extending parallel to the drive screws and meshed with these drive screws.

4. The circuit (24) according to any of the preceding claims, in which the number of drive and driven screw(s) (28, 30) on the pump (26) is comprised between 2 and 16.

5. The circuit (24) according to any of the preceding claims, in which the drive and driven screw(s) (28, 30) are rotatably mounted and guided in cylindrical housings (34, 38) on the same fixed body (26) of the pump (26).

6. The circuit (24) according to the preceding claim, in which the fixed body (26) is mounted at one end of the motor (33).

7. The circuit (24) according to any of the preceding claims, in which the pump (26) is fitted on a coolant reservoir (10).

8. The circuit (24) according to any of the preceding claims, further comprising a heat exchanger (14), at least one component to be cooled (16) and a temperature sensor (20) on this equipment, the circuit being devoid of a proportional valve (22) and said pump (26) being configured to be controlled by a control unit (18) according to signals emitted by said temperature sensor.

9. A vehicle, in particular a motor vehicle, comprising at least one circuit (24) according to any of claims 1 to 8.

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