Lubricating and / or cooling system and methods for the open-loop or closed-loop control of a lubricating and / or cooling system of this type

Abstract

The invention relates to a lubricating and / or cooling system (1) for use in a motor vehicle, in particular in an electric or hybrid motor vehicle, comprising an oil container (2) with oil and a pump assembly (3) for conveying the oil from the oil container (2), wherein, at least one pressure-side separating device (5) is arranged on the pressure side of the pump assembly (3), namely downstream of the pump assembly (3) in relation to a flow direction (X) of the oil, wherein a valve unit (6) is arranged on the pressure side of the pump unit (3), via which valve unit an oil volume flow through the pressure-side separating device (5) can be controlled in an open-loop or closed-loop manner, as well as methods for the open-loop or closed-loop control of a lubricating and / or cooling system of this type.

Description

[0001] Lubrication and / or cooling system and methods for regulating or controlling such a lubrication and / or cooling system

[0002] The invention relates to a lubrication and / or cooling system for use in a motor vehicle, in particular in an electric or hybrid motor vehicle, comprising an oil reservoir containing oil and a pump unit for pumping the oil from the oil reservoir, wherein a suction-side separating device is arranged on the suction side of the pump unit, namely with respect to a flow direction of the oil before the pump unit, and at least one pressure-side separating device is arranged on the pressure side of the pump unit, namely with respect to the flow direction of the oil after the pump unit, as well as a method for regulating or controlling such a lubrication and / or cooling system.

[0003] State of the art

[0004] In the field of automotive engineering, lubrication and / or cooling systems that use oil as a lubricant and / or coolant play a central role. In particular, when rotating (transmission) components come into contact with oil, foaming typically occurs. This negatively affects both the oil's ability to dissipate heat from temperature-critical active components and its lubricating properties.

[0005] When foam forms in oil, the proportion of air in the oil increases. A high proportion of air in the oil results in a lower specific heat capacity of the oil flow compared to the pure oil phase. This leads to a deterioration in heat transfer into the oil and thus a significant reduction in the oil's cooling capacity.

[0006] 2024P00100WQFurthermore, a high proportion of air in the oil leads to a reduced lubricity of the oil, which results in increased wear of the active components and more or less severe contamination of the oil.

[0007] An oil / air mixture has a lower density than a pure oil phase. Therefore, the flow rate of a pump would need to be increased to achieve the same mass flow rate as with a pure oil phase. The pump's efficiency is also lower when pumping an oil / air mixture.

[0008] The object of the invention is to provide an improved lubrication and / or cooling system for a motor vehicle, in particular for an electric or hybrid motor vehicle, which is characterized in particular by an improved use of oil as a lubricant and / or coolant.

[0009] Furthermore, it is an object of the present invention to provide a method for controlling a lubrication and / or cooling system according to the invention.

[0010] Description of the invention

[0011] The problem is solved by a lubrication and / or cooling system with the features according to claim 1.

[0012] Furthermore, the problem is solved by a method for controlling a lubrication and / or cooling system according to the invention with the features according to claim 9.

[0013] The lubrication and / or cooling system according to the invention is intended for use in a motor vehicle, in particular in an electric or hybrid motor vehicle,

[0014] 2024P00100WQ and includes an oil reservoir with oil and a pump unit for pumping the oil out of the oil reservoir.

[0015] Furthermore according to the invention, at least one pressure-side separating device is arranged on the pressure side of the pump unit, namely with respect to a flow direction of the oil after the pump unit.

[0016] According to the present invention, a valve unit is arranged on the pressure side of the pump unit, via which an oil volume flow through the pressure-side separating device can be regulated or controlled.

[0017] The design of the lubrication and / or cooling system according to the invention allows the oil used as a lubricant and / or coolant in the lubrication and / or cooling system to be easily cleaned of solid particles and air dissolved in the oil.

[0018] Preferably, a suction-side separating device is arranged on the suction side of the pump unit, namely with regard to the flow direction of the oil in front of the pump unit.

[0019] The valve unit can be designed as a temperature-sensitive valve unit or as a pressure-sensitive valve unit.

[0020] Preferably, the lubrication and / or cooling system on the pressure side of the pump unit has at least two oil paths, each of which is fluidly connected to at least one component to be lubricated and / or cooled.

[0021] Furthermore, at least one valve unit is functionally arranged in at least one oil path.

[0022] In a particularly preferred embodiment, the lubrication and / or cooling system has a first oil path, a second oil path and a third oil path, wherein the first oil path is connected to a rotor shaft of an electric machine.

[0023] 2024P00100WQ is fluidly connected, the second oil path is fluidly connected to at least one winding head of an electric machine and the third oil path is fluidly connected to a gear unit, wherein at least one valve unit is functionally arranged in the first oil path and / or in the second oil path and / or in the third oil path.

[0024] By dividing the volume flow, targeted cooling of the rotor and stator is possible.

[0025] In a particularly advantageous embodiment of the present invention, the suction-side separator is arranged in the oil reservoir at an angle to the direction of oil flow, specifically at an angle towards an oil intake point of the pump unit, and including an angle of inclination relative to the direction of oil flow. Due to the inclined arrangement of the suction-side separator in the oil reservoir, air bubbles within the oil are pushed upwards. This significantly reduces the air content in the oil, thereby enabling, in particular, greater heat dissipation from the oil-cooled components.

[0026] Preferably, the suction-side separating device has a larger mesh size than the pressure-side separating device. By providing a smaller mesh size on the pressure-side separating device, a lower pressure drop in the lubrication and / or cooling system is achieved, thus reducing the energy consumption of the pump unit.

[0027] In the inventive method for controlling a lubrication and / or cooling system according to the invention, the pressure-side separating device is only activated from a defined limit temperature of the oil, for example at a temperature greater than or equal to 60°C, and / or depending on a direction of rotation of the

[0028] The pump unit (2024P00100WQ) is permeated with oil. The inventive method for regulating or controlling the lubrication and / or cooling system can further reduce energy consumption in the oil cycle of the lubrication and / or cooling system.

[0029] Description of the characters

[0030] Fig. 1 shows a first embodiment of a lubrication and / or cooling system for an electric traction drive.

[0031] Fig. 2 shows a second embodiment of a lubrication and / or cooling system for an electric traction drive.

[0032] Fig. 3 shows a third embodiment of a lubrication and / or cooling system for an electric traction drive.

[0033] Fig. 4 shows a fourth embodiment of a lubrication and / or cooling system for an electric traction drive.

[0034] Fig. 5 shows a fifth embodiment of a lubrication and / or cooling system for an electric traction drive.

[0035] Fig. 6 shows a sixth embodiment of a lubrication and / or cooling system for an electric traction drive.

[0036] Fig. 7 shows a seventh embodiment of a lubrication and / or cooling system for an electric traction drive.

[0037] 2024P00100WQFig. 8 shows an eighth design variant of a lubrication and / or cooling system of an electric traction drive.

[0038] Figures 1 to 8 each show a simplified circuit diagram of a respective embodiment of a lubrication and / or cooling system 1 according to the present invention. The respective lubrication and / or cooling system 1 is a hydraulic arrangement of an electric traction drive of a hybrid or electric motor vehicle.

[0039] All execution variants have essentially the same components and are therefore provided with the same reference numeral.

[0040] The electric traction drive comprises an electric machine as a traction machine, a gear arrangement 12 and a lubrication and / or cooling system 1 with an electric pump unit 3.

[0041] The electric machine can be operated as a motor as well as a generator and has a stationary stator 11 and a rotatable rotor 10.

[0042] The electric pump unit 3 comprises a fluid pump 13 and an electric motor 14. In the embodiments of the lubrication and / or cooling system 1 shown in Figs. 1 to 5, the fluid pump 13 can be driven in one direction of rotation by the electric motor 14. In the embodiments of the lubrication and / or cooling system 1 shown in Figs. 6 to 8, the fluid pump 13 can be driven in two directions of rotation by the electric motor 14, namely in a first direction of rotation and in a second direction of rotation opposite to the first.

[0043] 2024P00100WQ The electric motor 14 of the pump unit 3 is controlled by an electrical control unit (not shown) which is connected to a data interface. The control unit is connected to the electric motor 14 of the pump unit 3 via a control line (not shown).

[0044] In all embodiments, the fluid pump 13 is fluidly connected on the suction side to an oil reservoir 2, in this case an oil sump, via a suction-side separating device 4. The oil reservoir 2 contains oil and thus forms an oil reservoir.

[0045] The term "suction side" describes any position in front of the fluid pump 13 with respect to a flow direction X of the oil.

[0046] In all embodiments, a heat exchanger 15 is arranged on the pressure side of the fluid pump 13.

[0047] The term "pressure side" describes any position downstream of the fluid pump 13 with respect to the flow direction X of the oil.

[0048] Furthermore, in all embodiments, the lubrication and / or cooling circuit 1 has, in addition to the suction-side separating device 4 (i.e., located upstream of the fluid pump 13 with respect to the oil flow direction X), a pressure-side separating device 5 (i.e., located downstream of the fluid pump 13 with respect to the oil flow direction X). The pressure-side separating device 5 always has a smaller mesh size than the suction-side separating device 4.

[0049] In all embodiments according to Fig. 1 to Fig. 8, a valve unit 6 is arranged on the pressure side of the pump unit 3, via which an oil volume flow through the pressure-side separating device 5 can be regulated or controlled.

[0050] 2024P00100WQThe lubrication and / or cooling system 1 further comprises at least three oil paths in all illustrated embodiments, namely a first oil path 7, a second oil path 8 and a third oil path 9, wherein the first oil path 7 is fluidly connected to the rotor 10 of the electric machine, the second oil path 8 is fluidly connected to at least one winding head of the stator 11 of the electric machine and the third oil path 9 is fluidly connected to the gear unit 12.

[0051] In all embodiments, a central oil path 16 downstream of the heat exchanger 15 divides into the first oil path 7, the second oil path 8 and the third oil path 9.

[0052] In the first embodiment according to Fig. 1, the pressure-side separating device 5 is arranged in the first oil path 7. Furthermore, a bypass channel 17 is provided in the first oil path 7, which allows the pressure-side separating device 5 to be bypassed. The valve unit 6 is provided in the bypass channel 17. The valve unit 6 is pressure-sensitive. The bypass channel 17 branches off from the first oil path 7 upstream of the pressure-side separating device 5 and opens into the first oil path 7 downstream of the pressure-side separating device 5.

[0053] The second embodiment according to Fig. 2 corresponds essentially to the first embodiment according to Fig. 1 with the difference that the valve unit 6 is not arranged in a bypass channel 17 to the first oil path 7, but directly in the first oil path 7, upstream of the pressure-side separating device 5.

[0054] In the third embodiment according to Fig. 3, the pressure-side separating device 5 is provided in the second oil path 8. A bypass channel 17 is provided in the second oil path 8, which allows the pressure-side separating device to bypass the flow.

[0055] 2024P00100WQ5 enables this. The valve unit 6 is provided in the bypass channel 17. The valve unit 6 is pressure-sensitive. The bypass channel 17 branches off from the second oil path 8 upstream of the pressure-side separating device 5 and opens into the second oil path 8 downstream of the pressure-side separating device 5.

[0056] In the fourth embodiment according to Fig. 4, the valve unit 6 is provided on the pressure side of the fluid pump 13, downstream of the heat exchanger 15, in the central oil path 16. The valve unit 6 is temperature-sensitive, namely designed as a wax valve.

[0057] Furthermore, a bypass channel 17 is provided in which the pressure-side separating device 5 is arranged. The bypass channel 17 branches off from the central oil path 16 upstream of the valve unit 6 and opens into the central oil path 16 downstream of the valve unit 6.

[0058] The temperature-sensitive valve unit 6 is actuated by the oil temperature. As shown in Fig. 4, the valve can bypass the pressure-side separating device 6; however, an additional bypass of the heat exchanger 15 would also be conceivable. In this case, as in the fifth embodiment according to Fig.

[0059] Figure 5 shows the heat exchanger 15 arranged in the bypass channel 17 upstream of the pressure-side separating device 5. This would provide additional potential savings in pressure loss.

[0060] In the sixth embodiment according to Fig. 6, the fluid pump 13 can be driven in two directions of rotation by the electric motor 14. Depending on the direction of rotation of the fluid pump 13, oil is pumped from the oil reservoir 2 via the suction-side separating device 4 and a respective check valve 18a, 18b either into the central oil path 16 or into a secondary oil path 19.

[0061] 2024P00100WO In this embodiment, the pressure-side separating device 5 and the valve unit 6 are provided in the auxiliary oil path 19. The valve unit 6, designed as a check valve, is arranged downstream of the fluid pump 13. The pressure-side separating device 5 is arranged downstream of the valve unit 6. The auxiliary oil path 19 opens into the oil reservoir 2 downstream of the pressure-side separating device 5.

[0062] In the central oil path 16, downstream of the fluid pump 13, between the fluid pump 13 and the heat exchanger 15, a further check valve 18c is arranged. Downstream of the heat exchanger 15, a pressure-sensitive valve 22 is provided in the second oil path 8; however, this has no influence on the pressure-side separating device 5.

[0063] In the seventh embodiment according to Fig. 7, the fluid pump 13 can be driven in two directions of rotation by the electric motor 14. Depending on the direction of rotation of the fluid pump 13, oil is pumped from the oil reservoir 2 via the suction-side separating device 4 and a respective check valve 18a, 18b, via a changeover valve 21 to the central oil path 16. If the oil pump 14 is operated in a first direction of rotation and the changeover valve 21 is opened so that the secondary oil path 19 is depressurized, the first oil path 7, which opens into the valve unit 6, is closed. If the oil pump is operated in a second direction of rotation, namely one opposite to the first direction of rotation, there is pressure in the secondary oil path 19, which leads to an open valve unit 6 and thus to a pressure-side separating device 5 through which oil flows. In the central oil path 16, the heat exchanger 15 is arranged downstream of the changeover valve 21.After the heat exchanger 15, the central oil path 16 splits into the three oil paths 7, 8, 9 in a known manner.

[0064] The valve unit 6 is designed as a hydraulic valve unit and is arranged in the first oil path 7, upstream of the pressure-side separating device 5.

[0065] 2024P00100WQ The eighth embodiment according to Fig. 8 corresponds essentially to the seventh embodiment according to Fig. 7, with the difference that the pressure-side separating device 5 is arranged in the second oil path 8. The valve unit 6 is represented in this embodiment by the changeover valve 21. A hydraulic valve 22 is provided in the first oil path.

[0066] 2024P00100WQ

[0067]

[0068] 1 Lubrication and / or cooling system 2 Oil reservoir

[0069] 3 pump unit

[0070] 4 Suction-side disconnect device 5 Pressure-side disconnect device 6 Valve unit

[0071] 7 First Oil Trail

[0072] 8 Second Oil Path

[0073] 9 Third Oil Path

[0074] 10 Rotor

[0075] 11 Stator

[0076] 12 Gear unit

[0077] 13 Fluid pump

[0078] 14 Electric motor

[0079] 15 heat exchangers

[0080] 16 Central Oil Path

[0081] 17 Bypass channel

[0082] 18a, 18b, 18c Check valve

[0083] 19 Secondary Oil Path

[0084] 20 Pressure-sensitive valve

[0085] 21 Changeover valve

[0086] 22 Hydraulic valve

[0087] 2024P00100WQ

Claims

Claims 1. Lubrication and / or cooling system (1) for use in a motor vehicle, in particular in an electric or hybrid motor vehicle, comprising an oil reservoir (2) containing oil and a pump unit (3) for pumping the oil from the oil reservoir (2), wherein at least one pressure-side separating device (5) is arranged on the pressure side of the pump unit (3), namely with respect to a flow direction (X) of the oil after the pump unit (3), characterized in that a valve unit (6) is arranged on the pressure side of the pump unit (3), via which an oil volume flow through the pressure-side separating device (5) can be regulated or controlled.

2. Lubrication and / or cooling system (1) according to claim 1 , characterized by the fact that a suction-side separating device (4) is arranged on the suction side of the pump unit (3), namely in relation to the flow direction (X) of the oil in front of the pump unit (3).

3. Lubrication and / or cooling system (1) according to claim 1 or 2, characterized in that the valve unit (6) is temperature sensitive.

4. Lubrication and / or cooling system (1) according to claim 1, 2 or 3, characterized in that the valve unit (6) is pressure-sensitive. 2024P00100WQ5. Lubrication and / or cooling system (1) according to one of claims 1 to 4, characterized in that the lubrication and / or cooling system (1) has at least two oil paths (7, 8, 9) on the pressure side of the pump unit (3), each of which is fluidly connected to at least one component (10, 11, 12) to be lubricated and / or cooled.

6. Lubrication and / or cooling system (1) according to claim 5, characterized by the fact that at least one valve unit (6) is functionally arranged in at least one oil path (7, 8, 9).

7. Lubrication and / or cooling system (1) according to one of claims 3 to 6, characterized in that a first oil path (7) of the lubrication and / or cooling system (1) is fluidly connected to a rotor shaft (10) of an electric machine, that a second oil path (8) of the lubrication and / or cooling system (1) is fluidly connected to at least one winding head (11) of an electric machine, and that a third oil path (9) of the lubrication and / or cooling system (1) is fluidly connected to a gear unit (12), wherein at least one valve unit (6) is functionally arranged in the first oil path (7) and / or in the second oil path (8) and / or in the third oil path (9). 2024P00100WQ15 8. Lubrication and / or cooling system (1) according to one of claims 1 to 7, characterized in that the suction-side separating device (4) is arranged in the oil reservoir (2) with an inclination to the flow direction (X) of the oil, namely in an inclination direction towards an oil intake point of the pump assembly (3), including an angle of inclination (a) with respect to the flow direction (X) of the oil.

9. Lubrication and / or cooling system (1) according to one of claims 1 to 8, characterized in that the suction-side separating device (4) has a larger mesh size than the pressure-side separating device (5).

10. Method for regulating or controlling a lubrication and / or cooling system according to one of claims 1 to 9, wherein the pressure-side separating device (5) is only through which oil flows from a defined limit temperature of the oil and / or depending on a direction of rotation of the pump unit. 2024P00100WQ

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