PUMP SYSTEM WITH CLUTCHES

Abstract

A pump system for a motor vehicle having a first pump and a second pump which can be driven by an electric motor and/or an internal combustion engine, wherein the first pump and the second pump can be coupled by a clutch. A method of operating a pump system in a motor vehicle includes driving a first pump and a second pump by an electric motor and/or an internal combustion engine by coupling the first pump and a second pump.

Claims

1-12. (canceled)

13. A pump system for a motor vehicle, the pump system comprising: a first pump; and a second pump which can be driven by an electric motor and/or an internal combustion engine, wherein the first pump and the second pump can be coupled by a clutch.

14. The pump system according to claim 13, wherein the internal combustion engine and the first pump can be coupled by a first clutch, and the first pump and the second pump can be coupled by a second clutch, and the electric motor and the second pump can be coupled by a third clutch.

15. The pump system according to claim 13, wherein a pressure line of the first pump and a pressure line of the second pump are connected via a connecting line.

16. The pump system according to claim 15, wherein at least one controllable and/or non-controllable valve is installed in the pressure line of the first pump and the pressure line of the second pump and/or the connecting line, in particular a flow valve, check valves, a pressure valve, or a directional control valve.

17. The pump system according to claim 15, wherein the pressure line of the first pump and the pressure line of the second pump are connected to at least one target unit.

18. The pump system according to claim 17, wherein a first target unit of the at least one target unit is a hydraulic control unit and a second target unit of the at least one target unit is a unit for a transmission to be cooled and lubricated.

19. The pump system according to claim 14, wherein the first clutch and the second clutch are shifting clutches, and the third clutch is a one-way clutch, wherein the shifting clutches are actuated in particular mechanically, electromechanically, hydraulically or pneumatically.

20. The pump system according to claim 19, wherein the one-way clutch has a freewheel against a direction of rotation of a shaft of the internal combustion engine.

21. The pump system according to claim 13, wherein the pumps are constant displacement pumps and/or variable displacement pumps and/or switching pumps.

22. A method of operating a pump system in a motor vehicle, the method comprising steps of: driving a first pump and a second pump by an electric motor and/or an internal combustion engine by coupling the first pump and a second pump.

23. The method of operating a pump system in a motor vehicle according to claim 22, wherein: the internal combustion engine drives the first pump by coupling a first clutch, and the electric motor drives the second pump by coupling a third clutch, or the internal combustion engine drives the first pump and the second pump by coupling the first clutch and the third clutch, or the electric motor drives the first pump and the second pump by coupling the second clutch and a third clutch.

24. A motor vehicle with the internal combustion engine or the electric motor and the pump system according to claim 13.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0038] Further features and advantages of the devices and the method are apparent from the following description of the embodiments with reference to the enclosed drawings. From these drawings shows:

[0039] FIG. 1 a schematic circuit diagram of the pump system;

[0040] FIG. 2 a pressure-volume flow-rate diagram of the individual operating states of the pump system;

[0041] FIG. 3 a table of the different coupling possibilities of the clutches according to the operating conditions of the pump system;

[0042] FIG. 4A a schematic circuit diagram of the pump system during the switching process of the motor vehicle;

[0043] FIG. 4B a schematic circuit diagram of the pump system during the clutch-hold process of the motor vehicle.

[0044] FIG. 4C a schematic circuit diagram of the pump system during cooling and lubrication of the transmission of the motor vehicle;

[0045] FIG. 4D a schematic circuit diagram of the pump system during the start-stop operation of the motor vehicle;

[0046] FIG. 4E a schematic circuit diagram of the pump system during cooling and lubrication of the transmission of the motor vehicle in hybrid mode;

[0047] FIG. 5A a flow diagram for the actuation of the clutches according to the operating states;

[0048] FIG. 5B a flow diagram for the actuation of the clutches according to the operating states;

[0049] FIG. 5C a flow diagram for the actuation of the clutches according to the operating states.

DESCRIPTION OF AN EMBODIMENT

[0050] It is clear to the skilled person that individual features described in different embodiments can also be implemented in a single embodiment, provided they are not structurally incompatible. Similarly, various features described in the context of a single embodiment can also be provided in several embodiments, either individually or in any suitable sub-combination. Moreover, all the features mentioned above or below with reference to the method are applicable to the system and vice versa.

[0051] FIG. 1 shows a schematic circuit diagram of one embodiment of a pump system 100. The pump system 100 comprises an internal combustion engine V that is configured in particular as the main unit for driving the motor vehicle, and is also known as internal combustion machine. The internal combustion engine V can, for example, be an in-line engine, a V-engine, a VR-engine, an H-engine, a W-engine, a boxer engine, a radial engine or the like.

[0052] Furthermore, according to this embodiment, an electric motor E is provided for the pump system 100, the power of which is preferably lower than that of the internal combustion engine V. However, the electric motor E can also be configured such that it can also be used as the main unit for driving the motor vehicle. For example, the electric motor E can be configured as a three-phase, linear, alternating current, direct current, universal, repulsion motor or the like.

[0053] According to the embodiment, the pump system 100 includes a first pump 1, also referred to as a main pump, and a second pump 2, also referred to as a secondary pump. The first pump 1 is preferably dimensioned larger than the second pump 2. Larger dimensioned is understood to mean a larger output as a result of a larger stroke volume. According to the embodiment, the pumps 1, 2 are preferably provided as constant pumps; however, they can also be configured as variable and/or switching pumps if required. The pumps 1, 2 are, for example, axial, diagonal, radial, rotary, centrifugal, impeller pumps or the like. The output performance of fixed displacement pumps is in particular directly dependent on the transmitted power of the drive units. In other words, the delivered volume flow rate and the pressure applied is determined by the transmitted torque of the internal combustion engine V or the electric motor E.

[0054] In the pump system 100 of this embodiment, the internal combustion engine V and the first pump 1 are coupled by a first clutch c1. It is thus possible to transmit a torque generated by the internal combustion engine V to the pump 1. In particular, the clutch c1 couples a shaft driven by the internal combustion engine V to another shaft driving the first pump 1. The clutch c1 is configured in particular as a shifting clutch, and therefore the shaft of the first pump 1 and the shaft of the internal combustion engine V can be optionally disconnected or connected. In addition, it is preferred that the clutches can be actuated, for example, mechanically, electromechanically, hydraulically or pneumatically so that they can be controlled by a control unit.

[0055] A second clutch c2 couples the first pump 1 and the second pump 2. This clutch is also preferably provided as a shifting clutch and can accordingly be operated as described above, thus can be optionally disconnected or connected. In this manner, a torque applied to the first pump 1 can be transmitted to the second pump 2. The clutch c2 couples in particular the shaft of the first pump and a shaft of the second pump 2.

[0056] In the present embodiment of the pump system, the electric motor E is coupled to the second pump 2 by the clutch c3. In particular, it is preferred that this clutch is a one-way clutch, and therefore this one-way clutch has a freewheel, particularly preferred in the direction opposite to the running direction of the electric motor E. This means that the electric motor cannot be decoupled from the second pump. Thus, it is possible to transmit a torque generated by the electric motor E to the pump 2. The clutch c3 couples in particular a shaft driven by the electric motor E to another shaft driving the second pump 2.

[0057] Further provided in the pump system 100 of the present embodiment is a tank T which serves as a storage container of the fluid to be pumped, in particular an oil-based fluid. According to the schematic circuit diagram, the tank T is connected to the suction side of the pumps 1,2 via a connecting line.

[0058] Furthermore, the pump system 100 is configured such that a check valve 3, 4 is installed in the pressure line 5, 6 of the pumps 1, 2, which pressure line is accordingly provided on the pressure side of the pumps 1, 2, and therefore a backflow of the fluid in the direction of the pumps is prevented.

[0059] According to the circuit diagram, the pump system 100 is configured such that downstream of the check valves 3, 4, the pressure lines 5, 6 of the first pump 1 and the second pump 2 are connected via a connecting line 7, wherein a hydraulic valve 8 is installed in particular at the junction between the pressure line of the second pump 2 and that of the connecting line 7, which hydraulic valve controls the fluid flow through the connecting line 7.

[0060] In the described embodiment, the pump system 100 is intended to supply a first target unit 10 and a second target unit 9 with a specific volume flow rate of the fluid and a specific pressure. The first target unit 10 is in particular a hydraulic control unit of a transmission, in which a specific pressure is required for the setting of various hydraulic actuators. The hydraulic actuators are, for example, part of a transmission, in particular an automatic transmission, of a motor vehicle. In a second target unit 9, for example, a transmission, in particular an automatic transmission, of a motor vehicle is to be lubricated and cooled with the pumped fluid.

[0061] One example of a method for driving a pump system 100 in a motor vehicle is described below by way of examples with reference to FIGS. 2, 3, and 4A-4E. For this purpose, different operation modes of the method are explained, which correspond to selected operating states of the motor vehicle.

[0062] FIG. 2 is a pressure/volume flow rate diagram reflecting the need for a fluid volume flow rate in connection with a required pressure of the fluid with regard to different operating states of the motor vehicle. The operating states refer, inter alia, to a transmission, in particular an automatic transmission, and the drive mode of a motor vehicle. In particular, a distinction is made here between the operating states “shifting”, “hold clutch”, “lubrication and cooling”. Additionally, there are the operating states “start-stop” and “hybrid”. These operating states can also be understood as temporal phases or processes during the operation of a motor vehicle.

[0063] The operating state “shifting” includes in particular the changing of a gear or, in other words, the change in the speed ratio in the transmission. During this process, the pressure p1 and the volume flow rate V1 are required.

[0064] The operating state “hold clutch” describes in particular the state in which the shifting clutch must be actively actuated for gear selection. During this process, the pressure p2 and the volume flow rate V2 are required.

[0065] The operating state “lubrication and cooling” is preferably provided during the transmission of torque through the transmission via the drive train to the wheels of the motor vehicle or, in other words, while power is being transmitted via the transmission. During this process, the pressure p3 and the volume flow rate V3 are required.

[0066] The operating state “start-stop” is preferably present when the motor vehicle is not in motion. During this operating state, in particular the internal combustion engine V is not in operation. During this process, the pressure p4 and the volume flow rate V4 are required.

[0067] The “hybrid” operating state is provided when the internal combustion engine V and the electric motor E are preferably operated in the motor vehicle. During this process, the pressure p5 and the volume flow rate V5 are required.

[0068] The following applies in particular to the required volume flow rate of the embodiment described here: V1<V4<V2<V5<V3

[0069] The following applies in particular to the required pressure of the fluid in the embodiment described here: p1>p2>p3=p4=p5

[0070] According to the above-described operating states of the motor vehicle, FIGS. 3 and 4A-4E illustrate the operation of the first pump 1 and the second pump 2, which are driven by the drive units V and E by coupling the clutches c1, c2, c3.

[0071] During the operating state “switching” (FIG. 4A) in the motor vehicle, the volume flow rate V1 and the pressure p1 are required. This volume flow rate and pressure are supplied particularly efficiently in terms of the drive energy required for this purpose by operating only the first pump 1 by means of the internal combustion engine V. In other words, due to the operation of the first pump 1 by coupling to the internal combustion engine V, the energy consumption to provide the required volume flow rate and pressure are lower than in all other configurations. Put differently, in the required power range, the energy required for operating the pump 1 is lowest by coupling to the internal combustion engine V. The clutch c1 is coupled for this purpose. However, the clutch c2 remains open and the electric motor E is out of operation. During the shifting process, the oil-based fluid is delivered from the tank 1 to the hydraulic control unit 10 by means of the first pump 1, as a result of which a setting of the actuators in the transmission, and thus “shifting”, is made possible.

[0072] During the operating state “hold clutch” (FIG. 4B) in the transmission, the volume flow rate V2 and the pressure p2 are required. This volume flow rate and pressure are supplied particularly efficiently in terms of the drive energy required for this purpose by operating the first pump 1 and the second pump 2 by means of the internal combustion engine V. To this end, the clutches c1 and c2 are coupled, and the electric motor E is out of operation. Due to the idling of the one-way clutch c3 in the direction opposite to the direction of rotation of the internal combustion engine V, no torque is applied to the electric motor E. While the clutch of the gear is held, the oil-based fluid is delivered, by means of the first pump 1 and the second pump 2, from the tank 1 to the hydraulic control unit 10 and into the transmission 9. The clutch is held in the transmission of the vehicle, which transmission is lubricated and cooled at the same time.

[0073] During the operating state “lubrication and cooling” (FIG. 4C) in the motor vehicle, the volume flow rate V3 and the pressure p3 are required. This volume flow rate and pressure is also supplied particularly efficiently in terms of the drive energy required for this purpose by operating the first pump 1 and the second pump 2 by means of the internal combustion engine V. In other words, in the required power range, the energy necessary to operate the pumps 1 and 2 is lowest by coupling to the internal combustion engine V. To this end, the clutches c1 and c2 are coupled, and the electric motor E is out of operation. Due to the idling of the one-way clutch c3 in the direction opposite to the direction of rotation of the internal combustion engine V, no torque is applied to the electric motor E. During this operating state of the motor vehicle, the oil-based fluid is delivered, by means of the first pump 1 and the second pump 2, from the tank T to the hydraulic control unit 10 and into the transmission 9. The transmission is lubricated and cooled.

[0074] During the operating state “start-stop” (FIG. 4D) in the motor vehicle, the volume flow rate V4 and the pressure p4 are required. This volume flow rate and pressure are supplied particularly efficiently in terms of the drive energy required for this purpose by operating the second pump 2 by means of the electric motor E since the operation of the internal combustion engine can be dispensed with in this operating state of the motor vehicle. During the start-stop operation of the motor vehicle, the clutch c3 is coupled and the second pump 2 pumps the oil-based fluid from the tank 1 into the transmission 9, thus cooling the latter. Furthermore, it is possible to additionally switch on the first pump 1 by actuating the clutch c2 (not shown in FIG. 4D) in order to further increase the volume to be conveyed.

[0075] During the “hybrid” operating state (FIG. 4E) in the motor vehicle, the volume flow rate V5 and the pressure p5 are required. This volume flow rate and pressure are also supplied particularly efficiently in terms of the drive energy required for this purpose by operating the first pump 1 by means of the internal combustion engine V and the second pump 2 by means of the electric motor E. The clutch c1 is coupled for this purpose. During this operating state of the motor vehicle, the oil-based fluid is delivered, by means of the first pump 1 and the second pump 2, from the tank 1 to the hydraulic control unit 10 and into the transmission 9 for cooling and lubrication.

[0076] In one embodiment, which is not shown in the figures, the pump system is configured such that only one drive unit is provided which is either an internal combustion engine V or an electric motor E. In this case, the drive unit is coupled to the first pump 1 or the second pump 2 either with the shifting clutch c1 or the one-way clutch c3. In this embodiment, too, the pumps 1, 2 are also switched according to the above-described principle using clutch c2, and therefore the pumps are operated in the power range which is particularly efficient with regard to the required energy.

[0077] FIGS. 5A, 5B, and 5C show a coherent flow diagram illustrating the actuation of the clutches according to the operating states described above in connection with corresponding method parameters. The required volume flow rate (Q.sub.req) in the individual operating states is estimated since the pump system in this embodiment does not have corresponding sensors to determine Q.sub.req. The parameters described in FIGS. 5A, 5B, and 5C are abbreviated as follows: [0078] Q.sub.req: required volume flow rate for an operating state [0079] n.sub.ICE: torque internal combustion engine [0080] M(n) E.sub.mot: electric motor torque in relation to the torque of the electric motor [0081] n.sub.N: nominal rotation speed of the electric motor [0082] n.sub.E: current rotation speed of the electric motor [0083] P.sub.max: maximum available power of the electric motor [0084] V.sub.P1/P2: cylinder capacity of the pumps P1 and P2 [0085] Q2E: volume flow rate of P2 driven by the electric motor: Q2 (n.sub.E) [0086] Q12E: volume flow rate of P1+P2 Q1 (n+Q2 (n.sub.E) [0087] Q1.sub.ICE: volume flow rate of P1 driven by the internal combustion engine: Q1 (n.sub.ICE) [0088] Q12 ICE: volume flow rate of P1+P2 driven by the internal combustion engine: Q1 (n.sub.ICE)+Q.sup.2 (n.sub.ICE) [0089] η: general efficiency factors

LIST OF REFERENCE NUMBERS

[0090] 1 first pump [0091] 2 second pump [0092] 3 check valve [0093] 4 check valve [0094] 5 pressure line [0095] 6 pressure line [0096] 7 connecting line [0097] 8 hydraulic valve [0098] 9 transmission of the motor vehicle [0099] 10 hydraulic control unit [0100] 100 pump system [0101] c1 shifting clutch [0102] c2 shifting clutch [0103] c3 one-way clutch [0104] E electric motor [0105] T tank [0106] V internal combustion engine