Dual clutch device, hydraulic device and method for controlling a hydraulic device

Abstract

The invention relates to a method (20) for controlling a hydraulic device (10) for a dual clutch device (12), the dual clutch device having: at least one hydraulically operable first clutch (K1) and a hydraulically operable second clutch (K2) for respective torque transmission; and a hydraulically operated clutch cooling device (C) for cooling at least one of the two clutches (K1, K2), and the hydraulic device (10) comprising a pump (PH, PL), a system pressure valve (SV) and a first clutch valve (KV1) for controlling a fluid pressure for clutch operation of the first clutch (K1) and a second clutch valve (KV2) for controlling a fluid pressure for clutch operation of the second clutch (K2), and the pump (PH, PL) provides at least the fluid pressure required for clutch operation, and with respect to clutch operation, only one of the two clutches (K1, K2) is operated as an activated clutch in operation-dependent manner via one of the following hydraulic operation states: a filling state (A1); a slipping state (A2); a first closed state (A3).

Description

Technical Field

[0001] The invention relates to a method for controlling a hydraulic device for a dual clutch device. The invention also relates to a hydraulic device and a dual clutch device. Background Art

[0002] A hydraulic device for a dual clutch device is described, for example, in DE 10 2019 123 965.6. A single-track configuration is shown in which each of the two clutches of the dual clutch device is associated with a clutch valve for controlling the fluid pressure for clutch operation and is provided with at least one spring accumulator and a check valve. Summary of the invention

[0003] The object of the present invention is to control a hydraulic device for a dual clutch device in a simple and reliable manner.

[0004] At least one of the objects is achieved by a method for controlling a hydraulic device having the features of the following exemplary embodiments. As a result, the dual clutch device can be operated efficiently, energy-savingly and reliably.

[0005] The control may include open-loop control and / or closed-loop control of the hydraulic device.

[0006] In the first closed state, the operating current may be a value less than the maximum operating current and greater than an operating current associated with the sum of the desired pressure of the fluid and a pressure hysteresis parameter.

[0007] The dual clutch device can be arranged in a powertrain of a vehicle, in particular a motor vehicle. The dual clutch device can act in a load-shiftable electric vehicle axle. The electric vehicle axle can have at least two shiftable gear stages.

[0008] The pump can be electrically driven. The pump can be associated with an electric motor. The pump can be operated independently of the speed of the clutch. As a result, a sufficient minimum speed of the pump can be achieved. In addition, the energy requirement of the pump can be reduced.

[0009] The clutch cooling system can be supplied hydraulically via the pump or via a further pump. The pump and the further pump can be operated via a common electric motor. The pump and the further pump can each be operated by their own electric motor. The speeds of the two electric motors can be set independently of each other.

[0010] The hydraulic device can have at least one spring pressure accumulator as a hydraulic capacity. The pressure spring storage can be associated with one of the two clutches. Each clutch can be associated with its own spring pressure accumulator. The spring pressure accumulator can be arranged between the pump and the corresponding clutch valve.

[0011] The hydraulic device can have at least one non-return valve. The non-return valve can be associated with one of the two clutches. Each clutch can be associated with its own non-return valve. The non-return valve can be arranged between the pump and the corresponding clutch valve.

[0012] The spring pressure accumulator can be arranged between the non-return valve and the corresponding clutch valve.

[0013] In a preferred embodiment of the present invention, there is a further hydraulically operated state, which corresponds to a second closed state, in which the clutch valve associated with the enabled clutch is operated by an operating current that is less than or equal to the maximum operating current and controls the pump speed according to the cooling speed required for clutch cooling. Here, the system pressure valve may not be operated in the second closed state. Here, the operating current of the system pressure valve may be zero. The operating current of the clutch valve associated with the enabled clutch may be a value less than the maximum operating current and greater than the operating current associated with the sum of the desired fluid pressure and the pressure hysteresis parameter.

[0014] Preferably, in the filled state, a predefined actuating current of the clutch valve and / or of the system pressure valve is set in a temperature-dependent manner, thereby making it possible to influence temperature-dependent conditions.

[0015] In a particular embodiment of the invention, the system pressure valve is operated in the slip state and / or in the first closed state by an operating current associated with a fluid system pressure that is higher by a pressure difference relative to the desired pressure of the fluid. Thus, a fluid pressure sufficient to maintain the desired pressure of the fluid can be set. The pressure difference in the slip state may not be equal to the pressure difference in the first closed state.

[0016] In a preferred embodiment of the invention, a first fluid supply section starts from the pump, which is associated with the first and second clutch valves, wherein the system pressure valve is arranged between the pump and the first and second clutch valves.

[0017] In a special embodiment of the invention, a second fluid supply section is arranged from the pump in parallel with the first fluid supply section to the clutch cooling device. The clutch cooling device can effect injection fluid cooling.

[0018] In a preferred embodiment of the invention, the activated clutch is a torque-transmitting clutch or a clutch selected for further torque transmission.

[0019] In a specific embodiment of the invention, the operating current of the non-activated clutch is set via the clutch valve associated therewith independently of the respective operating states of the clutch valve, the pump and the system pressure valve associated with the activated clutch. As a result, the fluid pressure in the fluid branch of the non-activated clutch can be set separately from the fluid pressure in the fluid branch of the activated clutch.

[0020] In a preferred embodiment of the invention, during the transition from an activated clutch to a non-activated clutch, a clutch valve associated with the clutch is closed. The fluid pressure in the fluid branch associated with the clutch may be briefly increased beforehand.

[0021] Furthermore, at least one of the objects specified above is achieved by a hydraulic device for carrying out a method having at least one of the features specified above.

[0022] At least one of the objects set out above is achieved by a dual clutch device having such a hydraulic device.

[0023] Further advantages and advantageous embodiments of the invention are apparent from the description and the drawings of the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is described in detail below with reference to the drawings. It is shown in detail:

[0025] Figure 1 A block diagram of a hydraulic system for a dual clutch device for carrying out a method in a special specific embodiment of the present invention is shown.

[0026] Figure 2 A block diagram of a further hydraulic system for a dual clutch device for carrying out the method in a special specific embodiment of the present invention is shown.

[0027] Figure 3 A block diagram of a further hydraulic system for a dual clutch device for carrying out the method in a special specific embodiment of the present invention is shown.

[0028] Figure 4 Shown for control Figure 1 Block diagram of the method of the hydraulic device in FIG.

[0029] Figure 5 Shown for control Figure 2 Block diagram of the method of the hydraulic device in FIG.

[0030] Figure 6 Shown for control Figure 3 Block diagram of the method of the hydraulic device in FIG.

[0031] Figure 7 Shown for control Figure 1 Block diagram of a method in another specific embodiment of the present invention for a hydraulic device in.

[0032] Figure 8 Shown for control Figure 1 Block diagram of a method in another specific embodiment of the present invention for a hydraulic device in. DETAILED DESCRIPTION

[0033] Figure 1 The block diagram of a hydraulic device 10 for a dual clutch device 12 for carrying out a method in a specific embodiment of the present invention is shown. The dual clutch device 12 is arranged in a drive train of a vehicle, in particular a motor vehicle, and has a hydraulically actuable first clutch K1 and a hydraulically actuable second clutch K2 for alternating torque transmission between a drive element, such as an internal combustion engine and / or an electric motor, and a transmission.

[0034] Furthermore, the dual clutch device 12 comprises a hydraulically operated clutch cooling device C for cooling at least one of the two clutches K1 , K2 . The first clutch K1 , the second clutch K2 and the clutch cooling device C are hydraulically connected to the hydraulic device 10 .

[0035] The hydraulic device 10 comprises a first pump and a second pump, both of which are driven by an electric motor E. Furthermore, a system pressure valve SV is provided, downstream of which a first clutch valve KV1 associated with the first clutch K1 and a second clutch valve KV2 associated with the second clutch K2 and arranged in parallel with the first clutch valve KV1 are provided.

[0036] The first clutch valve KV1 is configured to control the fluid pressure for clutch operation of the first clutch K1, and the second clutch valve KV2 is configured to control the fluid pressure for clutch operation of the second clutch K2. The first pump PH provides at least the fluid pressure required for clutch operation. The second pump PL can provide the fluid pressure required for clutch cooling via the clutch cooling device C.

[0037] A spring accumulator SC is connected as a hydraulic capacity upstream of the first clutch valve KV1 and the second clutch valve KV2. A check valve RV is arranged upstream of the respective spring accumulator SC. As a result, the first pump PH can increase the fluid pressure in the respective clutch-associated fluid branch 14 (single rail) and load the spring accumulator SC, wherein the fluid pressure drop toward the first pump PH is prevented by the respective check valve RV. As a result, the first pump 1 can be unloaded or even shut down when there is sufficient fluid pressure in the respective fluid branch 14.

[0038] exist Figure 2 1 shows a block diagram of another hydraulic device 10 for a dual clutch device 12 for carrying out a method in a specific embodiment of the present invention. Figure 1 The construction is the same as that drawn in , except for the differences explained below.

[0039] The first pump PH is driven by an electric motor E and the second pump PL is driven by another electric motor E. As a result, the rotational speed and the delivery volume of the second pump PL can be adjusted independently of the rotational speed of the electric motor E driving the first pump PH.

[0040] Figure 3 A block diagram of another hydraulic device 10 for a dual clutch device 12 for carrying out a method in a specific embodiment of the present invention is shown. Figure 2 The construction is the same as that drawn in , except for the differences explained below.

[0041] A first fluid supply section L1 that supplies the first and second clutches K1, K2 with fluid pressure for clutch operation is separated from a second fluid supply section L2 that supplies the clutch cooling device C with fluid pressure. The first fluid supply section L1 is associated with a spring-loaded check valve RVS.

[0042] The clutch cooling device C is supplied only by the second pump.

[0043] exist Figure 4 Shown in the figure is used for control Figure 1 Block diagram of method 20 for a hydraulic device in a dual clutch device. The dual clutch device is controlled in this case so that a distinction is always made between an activated clutch and a non-activated clutch. In particular, it is avoided that both clutches K1, K2 are activated at the same time. Preferably, when the clutch is controlled for torque transmission or for introducing torque transmission for hydraulic clutch operation, the clutch is activated. For example, the clutch that is in operation, that is to say that transmits torque, is the activated clutch. In the case of traction upshifts and coasting downshifts, the other, that is to say the next clutch that continues to transmit torque, is the activated clutch, in particular also during the movement from the disconnected state to the clutch half-engagement point.

[0044] In the case of drag downshift and coasting upshift, the next clutch is also the activated clutch, except when the torque of the clutch in operation, ie the clutch to be replaced with respect to the torque transmission, increases before the torque of the two clutches overlaps. Then, the clutch in operation is the activated clutch.

[0045] For clutch actuation, only one of the two clutches is therefore actuated as the activated clutch. Here, K1=0 and K2=0 mean that both clutches are not activated, K1=1 means that the first clutch K1 is activated, and k2=1 means that the second clutch K2 is activated.

[0046] If both clutches K1, K2 are inactive, the system actuation current I_pcv_Sys = 0, the first actuation current I1 associated with the first clutch K1 = 0 and the second actuation current I2 associated with the second clutch K2 = 0. The pump speed n is controlled according to the cooling speed n_cool required for clutch cooling. Depending on the parameter ind_act_clu, the clutch is switched as active or inactive.

[0047] If one of the two clutches K1, K2 is activated, it is actuated in a manner dependent on the operation via one of the hydraulic actuation states summarized in the module M1. Here, the first actuation state A1, the second actuation state A2, the third actuation state A3 and the fourth actuation state A4 can be set dependent on the parameter clu_state. If the parameter clu_state=2, then the actuation state A1 is selected, if clu_state=1, then the actuation state A2 is selected, if clu_state=0, then the actuation state A3 or A4 is selected, and this in turn depends on the existing pressure conditions.

[0048] The first control state A1 corresponds to a filling state in which the system pressure valve and the clutch valve associated with the activated clutch are controlled via a predefined actuating current, in particular temperature-dependent. The system actuating current I_pcv_Sys is equal to the predefined system filling actuating current I_sys_bef and the existing actuating current I_pcv_act associated with the activated clutch is equal to the predefined clutch filling actuating current I_pcv_bef. The pump speed n corresponds to the supply speed n_np at which a sufficient volume flow can be achieved.

[0049] The second control state A2 corresponds to a slipping state in which the clutch valve associated with the activated clutch is controlled as a function of the fluid desired pressure p_tgt_act of the activated clutch. The system pressure valve is operated via a system operating current I_pcv_Sys related to a fluid system pressure that is higher by a pressure difference Δp relative to the fluid desired pressure p_tgt_act in the fluid branch associated with the activated clutch.

[0050] The third actuation state A3 corresponds to a first closed state in which the clutch valve associated with the actuated clutch is operated by a maximum actuation current I_max. The system pressure valve is operated via a system actuation current I_pcv_Sys related to a fluid system pressure that is higher by a pressure difference Δp relative to a desired pressure p_tgt_act of the fluid in the fluid branch associated with the activated clutch.

[0051] The fourth control state A4 corresponds to the second closed state, in which the clutch valve associated with the activated clutch is maximally actuated by the maximum actuation current I_max and the pump speed n is controlled according to the cooling speed n_cool required for clutch cooling. This applies to the system actuation current I_pcv_Sys=0, for example in that the system pressure valve is not actuated.

[0052] The pressure relationship between the fluid pressure p_act present in the fluid branch associated with the activated clutch and the fluid desired pressure p_tgt_act together with the corresponding pressure hysteresis parameter p_hys_L or p_hys_H influences the selection between the third actuation state A3 and the fourth actuation state A4. The pressure hysteresis parameter p_hys_L or p_hys_H can be varied in dependence on the operating state, for example in dependence on temperature and pressure.

[0053] In all actuation states, the actuating current I_pcv_inact of the clutch valve associated with the inactive clutch is set as a function of the preset fluid setpoint pressure p_tgt_inact, more precisely independently of the fluid pressure in the fluid branch associated with the active clutch and the system fluid pressure.

[0054] In all actuation states, except the fourth actuation state, the pump speed n corresponds to a supply speed n_np which enables a sufficient volume flow and which is set constantly but can also be dependent on different operating states, such as temperature or pressure.

[0055] In the second actuation state A2 and in the third actuation state A3 , it should be ensured that the pressure difference Δp is greater than the pressure hysteresis variable p_hys_H.

[0056] Figure 5 Shown for control Figure 2 Since the first pump and the second pump are each operated by a separate electric motor, the first pump speed n_H of the first pump and the second pump speed n_L of the second pump can also be set separately from one another.

[0057] If the two clutches K1, K2 are not activated, the first and second speeds are set to the cooling speed n_cool required for clutch cooling. This also applies to the fourth control state A4. In other control states, on the other hand, the first pump speed n_H of the first pump is set so that a sufficient volume flow is provided while the second pump speed n_L of the second pump corresponds to the cooling speed n_cool.

[0058] exist Figure 6 Shown in the figure is used for control Figure 3 Since the second pump is only responsible for clutch cooling, the first pump speed n_H=0 when the first and second clutches K1 , K2 are not activated and are in the fourth actuation state A4 .

[0059] Figure 7 Shown for control Figure 1 A block diagram of a method 20 for a hydraulic device in another specific embodiment of the present invention. Figure 4 In addition to the method in , a transition method N1 is included here, which is used when changing the activated state between the two clutches K1 , K2 .

[0060] In transition method N1, the clutch that has become inactive or the spring pressure accumulator associated with the clutch is temporarily recharged via the maximum actuating current I_max before the fluid branch is decoupled from the system pressure. After the end of transition method N1, the other clutch is switched to active and the other clutch is switched to active in module M1. Figure 4 The control status described in .

[0061] If the clutch that becomes inactive is associated with a spring pressure accumulator, then Figure 8 Another possibility for the transition method N2 is described in which the spring pressure accumulator is charged only during the time period dt, thereby shortening the recharging process.

[0062] If the activation state is not yet to be changed between the clutches, the transition methods N1 and N2 are interrupted.

[0063] Description of Reference Numerals

[0064] 10 Hydraulic device 12 Dual clutch device 14 Fluid branch 20 Method K1 First clutch K2 Second clutch C Clutch cooling device PH First pump PL Second pump E Electric motor RV Non-return valve RVS Spring-loaded non-return valve SV System pressure valve KV1 First clutch valve KV2 Second clutch valve SC Spring pressure accumulator L1 First fluid supply section L2 Second fluid supply section A1, A2, A3, A4 Actuation states M1, M2, M3 Module N1, N2 Transmission method n Pump speed n_H First pump speed n_L Second pump speed n_np Supply speed n_cool Cooling speed I_pcv_Sys System actuation current I_sys_bef System filling actuation current I_pcv_act Actuation current I_pcv_inact Actuation current I_pcv_bef Clutch filling actuation current I_max Maximum actuation current I1 First actuation current I2 Second actuation current clu_state Parameter ind_act_clu Parameter p_hys_H Pressure hysteresis parameter p_hys_L Pressure hysteresis parameter p_act Fluid pressure p_tgt_act Expected fluid pressure p_tgt_inact Expected fluid pressure Δp Pressure difference.

Claims

1. A method (20) for controlling a hydraulic device (10) for a dual clutch device (12), the dual clutch device having: at least one hydraulically operable first clutch (K1) and a hydraulically operable second clutch (K2) for respective torque transmission; and a hydraulically operated clutch cooling device (C) for cooling at least one of the two clutches (K1, K2), and The hydraulic device (10) comprises a pump (PH, PL), a system pressure valve (SV), and a first clutch valve (KV1) for controlling fluid pressure to perform clutch operation of the first clutch (K1) and a second clutch valve (KV2) for controlling fluid pressure to perform clutch operation of the second clutch (K2), and The pump (PH, PL) at least provides the fluid pressure required for clutch operation, the system pressure valve (SV) is a two-position two-way solenoid valve, and With regard to the clutch actuation, only one of the two clutches (K1, K2) is actuated as the activated clutch in an operation-dependent manner via one of the following hydraulic actuation states: a filling state (A1) in which the system pressure valve (SV) and a clutch valve associated with the activated clutch are operated via a preset operating current (I_sys_bef, I_pcv_bef) for a preset period of time, respectively; a slipping state (A2) in which a clutch valve associated with the activated clutch is controlled according to a desired fluid pressure (p_tgt_act) of the activated clutch; A first closing state (A3) in which a clutch valve associated with the activated clutch is operated by an operating current that is less than or equal to a maximum operating current (I_max).

2. The method (20) according to claim 1, It is characterized in that There is another hydraulic control state, which corresponds to a second closed state (A4), in which the clutch valve associated with the enabled clutch is operated by an operating current that is less than or equal to a maximum operating current (I_max), and the pump speed (n) is controlled according to a cooling speed (n_cool) required for clutch cooling.

3. The method (20) according to claim 1 or 2, It is characterized in that In the slip state ( A2 ) and / or in the first closed state ( A3 ), the system pressure valve (SV) is operated by an operating current associated with a fluid system pressure that is higher by a pressure difference (Δp) relative to the fluid desired pressure (p_tgt_act).

4. The method (20) according to claim 1 or 2, It is characterized in that A first fluid supply section (L1) starts from the pump (PH) and is associated with the first and second clutch valves (KV1, KV2), wherein the system pressure valve (SV) is arranged between the pump (PH, PL) and the first and second clutch valves (KV1, KV2).

5. The method (20) according to claim 4, It is characterized in that A second fluid supply section (L2) is arranged from the pump (PL) in parallel with the first fluid supply section (L1) and leads to the clutch cooling device (C).

6. The method (20) according to claim 1 or 2, It is characterized in that The activated clutch is a clutch that transmits torque or a clutch that is selected for additional torque transmission.

7. The method (20) according to claim 1 or 2, It is characterized in that The actuating current (I_pcv_act) of the non-activated clutch is set via the clutch valve associated therewith independently of the respective operating states of the clutch valve (KV1, KV2), the pump (PH, PL) and the system pressure valve (SV) associated with the activated clutch.

8. The method (20) according to claim 1 or 2, It is characterized in that When transitioning from an activated clutch to a non-activated clutch, the clutch valve (KV1, KV2) associated with the clutch (K1, K2) is closed.

9. A hydraulic device (10) for carrying out the method (20) according to any one of the preceding claims.

10. A dual clutch device (12) having a hydraulic device (10) according to claim 9.

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