Method for operating electric traction drive for motor vehicle on demand

Abstract

The invention relates to a method for operating an electric traction drive on demand, said electric traction drive having a hydraulic device with an electric motor pump unit, which can be adjusted in two directions of rotation, i.e. In a first direction of rotation and in a second direction of rotation, which is opposite the first direction of rotation, such that a plurality of pump operating modes can be set, the motor pump unit is connected via a heat exchanger to at least two fluid outlets for partial volume flow, each of which is connected to at least one sub-component of the electric traction drive for cooling and / or heating and / or lubrication, and the motor pump unit is connected via the heat exchanger to at least two fluid outlets for partial volume flow, each of which is connected to at least one sub-component of the electric traction drive for cooling and / or heating and / or lubrication. If the electric traction drive is detected, at least one fluid outlet is additionally opened via at least one hydraulically switchable valve, the motor pump unit is activated on the basis of measured, calculated and / or saved state data of the electric traction drive, and the direction of rotation is adjusted on the basis of the detected vehicle operating mode in order to adjust the pump operating mode and the pump speed.

Description

Technical Field

[0001] The invention relates to a method for demand-dependent operation of an electric traction drive, wherein the electric traction drive has an electrically controllable motor-pump unit and a hydraulic device. Background Art

[0002] The drive concept of electric and partially electric vehicles is nowadays different from that of conventional internal combustion engine-driven vehicles. With the elimination of the internal combustion engine as a reliable heat source for interior air conditioning and the requirements for heating and cooling of new drive components in electric and partially electric drive concepts, the heating, cooling and lubrication systems have also undergone fundamental changes. The focus of the development of such systems is on the efficient and demand-based use of available energy, taking into account all safety-related framework conditions, so as to operate electrically driven vehicles in a range-optimized manner. Summary of the invention

[0003] The object of the present invention is to specify an improved method for demand-dependent operation of an electric traction drive.

[0004] Said need can be met by the subject matter of embodiments of the present invention. Advantageous embodiments of the present invention are described below.

[0005] The method according to the invention serves to operate an electric traction drive in a demand-dependent manner.

[0006] According to the invention, the electric traction drive comprises a hydraulic device with an electric motor pump unit, wherein the motor pump unit is controllable in two rotational directions, namely in a first rotational direction and in a second rotational direction opposite to the first rotational direction, so that a plurality of pump operating modes can be set.

[0007] Furthermore, according to the invention, the motor pump unit is connected via a heat exchanger to at least two fluid outlets for partial volume flows, which are each connected to at least one subcomponent of the electric traction drive for cooling and / or heating and / or lubrication, wherein if the direction of rotation of the motor pump unit is reversed, at least one fluid outlet is additionally opened or closed via at least one hydraulically switchable valve.

[0008] According to the invention, the motor pump unit is activated based on measured, calculated and / or stored state data of the electric traction drive and the direction of rotation and thus the pump operating mode and the pump speed are adjusted based on the detected vehicle operating mode.

[0009] The vehicle operating mode is preferably selected by the vehicle driver, a superordinate driving mode controller and / or on the basis of driving route data.

[0010] In addition to a passive pump operating mode in which the motor pump unit is not running, i.e., a pump standby mode, at least three active pump operating modes can preferably be set, i.e., a first pump operating mode in which the electric motor of the motor pump unit is operated by means of speed regulation in a first rotational direction of the electric motor, a second pump operating mode in which the electric motor of the motor pump unit is operated by means of speed regulation in a second rotational direction, and / or a third pump operating mode in which the electric motor of the motor pump unit is operated in reverse by means of speed regulation in the first rotational direction and the second rotational direction.

[0011] The motor pump unit is preferably set into the first pump operating mode based on temperature data of subcomponents of the electric traction drive which are measured, calculated and / or stored for the respective vehicle operating mode.

[0012] Here, when approaching and / or exceeding and / or falling below limit values ​​defined for the corresponding subcomponents of the electric traction drive, a cooling and / or heating requirement is preferably determined for each of the subcomponents and a total cooling and / or heating requirement is calculated, wherein the direction of rotation and thus the pump operating mode and the pump speed are adjusted based on the total cooling and / or heating requirement.

[0013] Furthermore, when actively cooling and / or heating and / or lubricating the electric traction drive, an actual total volume flow of the fluid in the hydraulic device is preferably determined and compared with a defined desired total volume flow, wherein, if the actual total volume flow deviates from the desired total volume flow for a defined period of time, the motor pump unit is adjusted to operate alternately in a first rotational direction and in a second rotational direction at maximum pump speed, and this is repeated until the actual total volume flow no longer deviates from the desired total volume flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is described below by way of example with reference to the accompanying drawings.

[0015] Figure 1 The hydraulic system of an electric traction drive is shown.

[0016] Figure 2 The sequence of a method for operating an electric traction drive is schematically shown.

[0017] Figure 3 Shown for Figure 2 Detailed flow chart of the first box in .

[0018] Figure 4 Shown for Figure 2 Detailed flow chart of the second box in .

[0019] Figure 5 Shown for Figure 2 Detailed flow chart of the third-party boxes in .

[0020] Figure 6 Shown for Figure 2 Detailed flow chart of the fourth box in .

[0021] Figure 7 Shown for Figure 2 Detailed flow chart of the fifth box in .

[0022] Figure 8 A schematic sequence for switching between vehicle operating modes is shown.

[0023] Fig. 9 A table with conditions for transitioning between vehicle operating modes is shown. DETAILED DESCRIPTION

[0024] exist Figure 1 , a simplified circuit diagram of a hydraulic device 1 of an electric traction drive is shown by way of example, in which the method 100 according to the invention is applied. However, the application of the method 100 according to the invention is not restricted precisely to the illustrated embodiment variants—the illustrated embodiment variants serve only as a basis for describing the method 100 according to the invention.

[0025] In addition to the electric machine and transmission arrangement GBX as a traction machine, the electric traction drive also has a hydraulic device 1 with an electric motor pump unit 2 .

[0026] The electric machine can be operated both as a motor and as a generator and has a stationary stator S and a rotatably movable rotor RS.

[0027] The electric motor pump unit 2 has a fluid pump 6 and an electric motor 7 , wherein the fluid pump 6 can be driven in two rotational directions, namely in a first rotational direction A and in a second rotational direction B opposite to the first rotational direction A, via the electric motor 7 .

[0028] The electric motor 7 of the motor pump unit 2 is controlled via an electric control unit 8 which is connected to a data interface 9 . The control unit 8 is connected to the electric motor 7 via a control line 10 .

[0029] The fluid pump 6 is connected to a fluid sump 13, in the present embodiment to an oil sump, on the suction side and the pressure side via a first non-return valve 11a and a second non-return valve 11b and a filter element 12. Depending on the direction of rotation A, B of the fluid pump 6 of the motor pump unit 2, one of the two non-return valves 11a, 11b is in an open position, while the respective other of the two non-return valves 11a, 11b is in a closed position.

[0030] By means of the method 100 for operating an electric traction drive, in addition to lubrication, in particular the functions of cooling, heating and pre-regulation and readjustment of the electric traction drive and switching between the functions can be realized in order to achieve an optimal energy distribution within the system. For this purpose, the electric traction drive is divided into several subcomponents, each of which may require cooling or heating. For example, in the present exemplary embodiment, the electric machine, more precisely the stator S of the electric machine and its rotor R, the transmission device GBX, the fluid sump 13, the heat exchanger 3 and the hydraulic device 1 represent each a subcomponent of the electric traction drive.

[0031] The motor pump unit 2 of the hydraulic device 1 is connected to three fluid outlets 4a, 4b, 4c for partial volume flows via a switching valve 14 and a heat exchanger 3 located upstream of the switching valve 14 - the first fluid outlet 4a is fluidly connected to the transmission device GBX of the electric traction drive, the second fluid outlet 4B is fluidly connected to the stator S of the electric motor of the traction drive, and the third fluid outlet 4c is fluidly connected to the rotor R of the electric motor of the electric traction drive.

[0032] The third fluid outlet 4 c can be opened and closed via a hydraulically switchable valve 5 .

[0033] exist Figure 2 The sequence of a method 100 for demand-dependent operation of an electric traction drive is schematically shown in FIG.

[0034] Method 100 for demand-based operation of an electric traction drive proposes different pump operating modes, which are associated with a vehicle operating mode 1000, 2000, 3000, 4000 selected by a vehicle driver of the vehicle or automatically by a superior operating strategy, for example based on a selected route, system status, predictions based on the current operating state, etc.

[0035] In the present non-limiting embodiment, the vehicle driver and / or a superior control unit should be able to select between the following four vehicle operating modes 1000, 2000, 3000, 4000:

[0036] -Basic Mode 1000:

[0037] The mode is used as a standard driving mode in which all requirements for defined boundary conditions are met. In this case, a balanced and nearly realistic driving cycle is used as the basis for the evaluation, which exceeds the standard "WLTC" (category C of "WLTP" : w orldwide harmonized l heavy-duty vehicles t est pThe power limits are observed within defined time periods and the temperatures remain within defined ranges or below defined limit values.

[0038] - "Performance" mode 2000:

[0039] In partially oil-cooled and purely oil-cooled electric traction machines, the cooling oil requirement of the rotor and stator varies - depending on the respective operating point - in particular due to the copper, iron and magnetic losses occurring in the electric machine. For maximum thermal availability, i.e. the longest possible and high power availability of the electric machine, the level and distribution of the oil mass flow between the rotor and the stator are set as required and predictive. The focus here is on the thermal state, in order to keep all subcomponents of the electric traction drive below their critical temperature for as long as possible, thereby maximizing thermal availability. In this mode, improving energy efficiency is only of secondary importance.

[0040] - "Efficiency" mode 3000:

[0041] In this mode, the energy consumption of the electric traction drive for any driving cycle is minimized or the efficiency of the electric traction drive is maximized. This is done by taking the energy of the electric traction drive into account as a whole. In addition to the components of the electric motor of the electric traction drive, the reducer and the cooling lubricant are kept between certain temperature limits in order to operate the electric traction drive in a thermally optimal point. In particular, the hydraulic traction losses of the electric motor pump unit and the electric drive power are taken into account. By distributing the generated heat according to demand, the temperature of different areas or subcomponents can be increased or decreased in a targeted manner, so as to set the most energy-efficient operating point from the perspective of the overall system.

[0042] - "Regulation" mode 4000:

[0043] Here, a distinction is made between pre-regulation and readjustment of the electric traction drive. The "regulation" mode is activated when the vehicle is stationary. Before or after the operation of the electric traction drive, it may be necessary to regulate the system so that it can still operate efficiently or to protect the system from damage. For example, before starting, it makes sense to slightly preheat the system at low temperatures in order to reduce losses. If the system is brought from high-load operation, such as maximum speed, to a standstill (storage to, parking to) in the shortest possible time, active cooling may be required after operation.

[0044] During preconditioning—mainly during a cold start—subcomponents of the electric traction drive, such as the transmission unit GBX and the electric machine, are brought to an operating temperature that is optimal for efficiency before the actual driving.

[0045] Reconditioning is primarily used after a trip with increased power demand in order to cool the high temperatures of the subcomponents of the electric traction drive that occur during this trip to conventional operating temperatures.

[0046] The motor pump unit 2 is activated based on measured, calculated and / or stored state data of the electric traction drive and the direction of rotation and thus the pump operating mode and the pump speed are adjusted based on the detected vehicle operating mode 1000 , 2000 , 3000 , 4000 .

[0047] The pump operating mode is set by switching the rotational direction A, B of the motor pump unit 2. By switching the rotational direction, the fluid distribution on the rotor R and the stator S of the electric machine of the electric traction drive is changed, wherein a constant small volume flow is always conducted via the transmission device GBX. In addition to the two rotational directions A, B with a constant percentage distribution, an intermittent reverse operation is also shown, wherein the flow between the extremes of the two rotational directions A, B can be mapped in a time average.

[0048] In total, therefore, three pump operating modes can be adjusted:

[0049] a first pump operating mode, in which the electric motor of the motor pump unit 2 is operated by means of a rotational speed control in a first rotational direction A of the electric motor,

[0050] a second pump operating mode, in which the electric motor of the motor pump unit 2 is operated with a rotational speed control in a second rotational direction B,

[0051] A third pump operating mode, in which the electric motor of the motor pump unit 2 is operated in reverse by means of a rotational speed control in the first rotational direction A and in the second rotational direction B.

[0052] The method 100 comprises, in a first step, a plurality of query boxes 101, 102, 103. In the query box 101, it is queried whether active cooling of the electric traction drive or at least one of its subcomponents is required. In the query box 102, it is queried whether active heating of the electric traction drive or at least one of its subcomponents is required. In the query box 103, it is queried whether adjustment of the electric traction drive or at least one of its subcomponents is required. If all of these query boxes 101, 102, 103 are answered with "No", the motor pump unit 2 does not have to be adjusted into operation - the motor pump unit is in a passive pump stop mode (box 200). If one of the query boxes is answered with "Yes", the electric motor pump unit 2 is adjusted or set to an active pump operation mode (box 300) ( Figure 2 ).

[0053] For the functionally optimal operation of the electric traction drive, a plurality of predefined function blocks 400, 500, 600, 700, 800, 900 are subsequently executed according to the query blocks 101, 102, 103 answered with "yes", wherein in the case of the two query blocks 101 and 102 regarding cooling and / or heating, the same function blocks are executed in the same order, i.e. ( Figure 2 ):

[0054] - Function box "Set operating mode and load parameterization" 400

[0055] - Function box "Determine influencing factors" 500

[0056] - Function box "Scaling and calculation of pump speed" 600

[0057] - Function box "Diagnostics" 700

[0058] - Functional block "Release a stuck fluid pump" 800, and

[0059] Function box “Other application-specific function boxes” 900 .

[0060] In the case of the query box 103 regarding adjustment, the following function boxes are performed in order: Figure 2 ):

[0061] - Function box "Set operating mode and load parameterization" 400

[0062] - Function box "Scaling and calculation of pump speed" 600

[0063] - Function box "Diagnostics" 700

[0064] - Functional block "Release a stuck fluid pump" 800, and

[0065] Function box “Other application-specific function boxes” 900 .

[0066] exist Figures 3 to 7 4 , each functional block 400 , 500 , 600 , 700 , 800 , 900 is shown in detail.

[0067] Figure 3Function box "Set operating mode and load parameterization" 400 is shown in detail. In the function box 400, three query boxes 401, 402, 403 are performed in sequence. In query box 401, it is queried whether "performance" mode 2000 is allowed and activated. In query box 402, it is queried whether "efficiency" mode 3000 is allowed and activated. In query box 403, it is queried whether "regulation" mode 4000 is allowed and activated. If each query box in the query boxes is answered with "no", function box 414 "load parameterization for basic mode" is performed. If query box 401 is answered with "yes", function box 411 "load parameterization for performance mode" is performed. If query box 402 is answered with "yes", function box 412 "load parameterization for efficiency mode" is performed. If query box 403 is answered with "yes", function box 413 "load parameterization for regulation mode" is performed.

[0068] The method 100 for operating an electric traction drive uses so-called influencing factors. Each subcomponent can report a demand for fluid flow for cooling and / or heating and / or regulation and / or lubrication. The sum of all demands results in the total demand for the electric traction drive. In addition to the quantity, the rotation direction A, B of the fluid pump 6 is also defined by the selected subcomponents. For situations where neither of the two rotation directions A, B is suitable, the hydraulic device can also provide intermittent reverse operation, i.e. the feasibility of a third pump operating mode. In the third pump operating mode, a flow in two directions is established in the time average, which is between the flow in the two rotation directions A, B.

[0069] The two variables—speed and direction of rotation—are then proportionally adjusted to the hydraulic device 1 and the corresponding speed is output to the fluid pump 6. Furthermore, the speed can also be limited by different influencing variables.

[0070] The method 100 is designed to be fully parameterizable, so that it can be easily scaled and applied to different electric traction drives. Individual subfunctions can be deactivated, and all desired values ​​and characteristic diagrams can be freely parameterized.

[0071] The selection of vehicle operating mode 1000, 2000, 3000, 4000 is performed by the vehicle driver and / or by automated selection via a control unit. The desired values ​​and parameterization (characteristic curves and "lookup" tables) are optimally set via the selected vehicle operating mode 1000, 2000, 3000, 4000. For any necessary transition phases between vehicle operating modes 1000, 2000, 3000, 4000, values ​​are interpolated.

[0072] If a switch is required between two vehicle operating modes 1000, 2000, 3000, 4000, it is checked whether this switch is currently permitted and possible. In particular, when switching to "performance" mode 2000, temperature levels and cooling capacities must be met, since an increased power loss and thus a higher thermal load are expected for this vehicle operating mode.

[0073] If a direct switch to the desired vehicle operating mode 1000, 2000, 3000, 4000 is not possible, an attempt is made to put the system into a corresponding state - which can be done depending on the system - for up to several minutes. For this purpose, the vehicle driver is optionally fed back when the "new" operating mode will be fully available.

[0074] Selectable vehicle operating modes 1000 , 2000 , 3000 , 4000 specify thermal target states in order to achieve the respective goals of vehicle operating modes 1000 , 2000 , 3000 , 4000 .

[0075] Figure 4 The function block "determine influencing factors" is shown in detail. In the function block 500, four function blocks 501, 502, 503, 504 are carried out in parallel with each other. In function block 501, the cooling and / or heating requirement of the rotor R of the electric motor of the electric traction drive is determined. In function block 502, the cooling and / or heating requirement of the stator S of the electric motor of the electric traction drive is determined. In function block 503, the cooling and / or heating requirement of the oil sump 13 of the hydraulic device 1 of the electric traction drive is determined. In function block 504, the cooling requirement is determined by the load point and the temperature gradient. From the determined cooling and / or heating requirement, a function block 512 "calculate total influencing factors" is derived. From the function block 501, a function block 512 for specifying the rotation direction A, B of the fluid pump 6 of the motor pump unit 2 of the hydraulic device 1 is further derived.

[0076] Figure 5 The function block "scaling and calculating pump speed" 600 is shown in detail. In the function block 600, three function blocks 601, 602, 603 are performed in sequence. In the function block 601, the pump speed of the fluid pump 6 is calculated. In the function block 602, rapid pump speed changes are suppressed, for example, in order to minimize the NVH characteristics and energy consumption of the fluid pump 6. In the function block 603, the pump speed is limited according to the current vehicle operating state 1000, 2000, 3000, 4000.

[0077] Figure 6The function block "Diagnosis" 700 is shown in detail. In the function block 700, the four function blocks 500, 600, 701, 702 are performed in sequence. The first two function blocks 500 and 600 have already been Figure 4 and Figure 5 In function box 701, the current fluid circulation rate is determined. In function box 702, the expected pump speed and flow are checked for plausibility, followed by query box 703: Is "VF current ≤ VF expected". If the query box 703 is answered with "no", then "diagnosis normal" 704. If the query box is answered with "yes", then the Figure 7 Function box "Release a stuck fluid pump" 800.

[0078] Figure 7 The functional block "Releasing a stuck fluid pump" 800 is shown in detail. In the functional block 800, four functional blocks 801, 802, 803, 700 are performed in sequence. In the functional block 801, the fluid pump 6 is operated alternately in a first rotational direction A and in a second rotational direction B at a maximum rotational speed within a defined time period. The functional block 801 can be repeated up to three times. In the functional block 802, the fluid pump is operated at a defined test rotational speed and test rotational directions A, B. In the functional block 803, a plausibility check is performed, followed by a query block 804: Is "VF 实际 ≤(VF 期望 +ΔVF)". If the query box 804 is answered with "no", the function box 700 is performed, as shown in FIG. Figure 6 If the query box is answered with "yes", function box 801 starts again, followed by function boxes 802, 803 and query box 804: Is "VF 实际 ≤(VF 期望 +ΔVF)", and until query block 804 is answered with "No".

[0079] Figure 8 The flowchart shown in the schematic diagram shows the switching between different vehicle operating modes 1000, 2000, 3000, 4000 and the start 9000 and stop 7000 of the method 100 for operating an electric traction drive. The exemplary vehicle operating modes 1000, 2000, 3000, 4000 do not have to be used in their entirety, but other vehicle operating modes can also be expanded. In addition, the transition between the individual vehicle operating modes 1000, 2000, 3000, 4000 can also be prevented if it is not permitted.

[0080] If the method 100 is started, a query is made whether a regulation should be carried out (query block 8000). The start 9000 of the method 100 is different from the vehicle start 5000. If the electric traction drive is to be regulated, a transition is made to the "regulation" mode 4000, otherwise a transition is made to the basic mode 1000. Depending on the definition and configuration, the initial mode can also be another mode.

[0081] If the “regulation” mode 4000 is executed, a transition automatically occurs from the “regulation” mode to the basic mode 1000 or to the mode defined as the initial mode when the vehicle is started 5000 .

[0082] The transition between the individual vehicle operating modes 1000, 2000, 3000, 4000 is always carried out according to the same structure, in that the state of the electric traction drive is checked and thus determined as follows: Is the state permitted for the "new" vehicle operating mode 1000, 2000, 3000, 4000 (query box 1001, 2001, 3001). If all conditions are met, then a transition is made to the new vehicle operating mode 1000, 2000, 3000, 4000 (function box 1002, 2002, 3002). If all conditions are not met, then an attempt is made to put the electric traction drive into a suitable state. If this is not possible, for example after a defined time has passed, then the current vehicle operating mode remains set. Necessary conditions (not limited to the conditions) are the rotor R (magnet) temperature, the stator temperature, the oil sump 13 temperature, and the fluid temperature and fluid flow. When the vehicle is stationary (parking of the vehicle) 6000, a switch is made to the "regulation" mode 4000. Only after the electric traction drive is in a (thermally) safe state is the method 100 stopped 7000.

[0083] exist Fig. 9 , the following table is shown: the table shows by way of example in the left column the different transitions between the vehicle operating modes basic mode 1000 , “performance” mode 2000 and “efficiency” mode 3000 , and in the right column the conditions to be met for the transitions.

[0084] According to the vehicle operation mode 1000, 2000, 3000, 4000, according to Fig. 9 The values ​​shown in the table are not allowed to exceed or fall below certain parameters. For example, for the "Performance" mode 2000, the current rotor temperature T 转子，当前 and the current stator temperature T 定子，当前The temperature of the rotor R and stator S should therefore be lowered when switching to the basic mode 1000 or the "performance" mode.

[0085] It should be noted that the exact limiting values ​​and conditions are highly dependent on the electric traction drive in which the method 100 is used. In addition, the higher-level vehicle operating strategy is a decisive factor for the parameterization.

[0086] In current electric traction drives, the available drive torque is reduced starting from a defined temperature in order to thermally protect the electric traction drive and its subcomponents. As a result, part of the power potential remains unused ("torque derating").

[0087] By using the hydraulic device 1, the fluid volume flow can be set flexibly, so that the "torque derating" is delayed, so that more torque is available for a certain time even at higher temperatures. Specifically, the torque is reduced only at higher temperatures, because the fluid volume flow is not only directly related to the electric machine of the electric traction drive, but can also be set by other variables, such as temperature and gradient, fluid flow and temperature, rotational speed of the electric machine, torque, etc.

[0088] Reference numerals list

[0089] 1 Hydraulic device

[0090] 2 Motor pump unit

[0091] 3 Heat exchanger

[0092] 4a First fluid outlet

[0093] 4b Second fluid outlet

[0094] 4c Third fluid outlet

[0095] 5 Hydraulically switchable valves

[0096] 6 Fluid Pump

[0097] 7 Electric Motor

[0098] 8 Control unit

[0099] 9 Data Interface

[0100] 10 Control circuit

[0101] 11a First check valve

[0102] 11b Second check valve

[0103] 12 Filter element

[0104] 13 Fluid sump

[0105] 14 Switching valve

[0106] 100 Method for operating an electric traction drive

[0107] 101, 102, 103,

[0108] 401, 402, 403,

[0109] 703, 804, 1001,

[0110] 2001, 3001, 8000 query box

[0111] 200, 300, 400,

[0112] 411, 412, 413,

[0113] 414, 500, 501,

[0114] 502, 503, 504,

[0115] 511, 512, 600,

[0116] 601, 602, 603,

[0117] 700, 701, 702,

[0118] 704, 800, 801,

[0119] 802, 803, 900,

[0120] 1002, 2002, 3002 function box

[0121] 1000 Basic Mode

[0122] 2000 "Performance" mode

[0123] 3000 "Efficiency" mode

[0124] 4000 "Adjustment" mode

[0125] 5000 Vehicle Start 6000 Vehicle stop (vehicle parking)

[0126] 7000 Method stopped

[0127] 9000 Method Start

[0128] R Rotor

[0129] S Stator

[0130] GBX Transmission Unit

[0131] T Temperature

[0132] T 定子，当前 Current stator temperature

[0133] T 转子，当前 Current rotor temperature

[0134] T 定子，最大 Maximum stator temperature

[0135] T 转子，最大 Maximum rotor temperature

[0136] ΔT 定子，XXX Temperature difference of stator at the boundary value in XXX mode (XXX = basic, performance, efficiency)

[0137] ΔT 转子，XXX Temperature difference of the rotor at the boundary value in XXX mode (XXX = basic, performance, efficiency)

[0138] T 油底壳 Oil sump temperature

[0139] T 油底壳，XXX Oil sump temperature at the limit value in XXX mode (XXX = basic, performance, efficiency)

[0140] QF Heat Flow

[0141] QF 冷却水 Cooling water heat flow

[0142] QF XXX,min Heat flow at the boundary value in XXX mode (XXX = basic, performance, efficiency)

[0144] VF Volume Flow

[0145] VF 实际 Actual volume flow

[0146] VF 期望 Expected volume flow

[0147] ΔVF Difference between actual volume flow and desired volume flow + "Yes"

[0148] - "no"

Claims

1. A method (100) for demand-dependent operation of an electric traction drive, wherein the electric traction drive has a hydraulic device (1) with an electric motor pump unit (2), wherein the motor pump unit (2) is adjustable in two directions of rotation, namely in a first direction of rotation (A) and in a second direction of rotation (B) opposite to the first direction of rotation (A), so that a plurality of pump operating modes can be set, and wherein the motor pump unit (2) is connected via a heat exchanger (3) to at least two fluid outlets (4a, 4b, 4c) for partial volume flows, the fluid outlets being respectively connected to at least one of the at least one fluid outlets of the electric traction drive. The invention relates to a motor pump unit (2) for cooling and / or heating and / or lubrication, wherein if the rotational direction of the motor pump unit (2) is adjusted in the reverse direction, at least one fluid outlet (4a, 4b, 4c) is additionally opened via at least one hydraulically switchable valve (5), wherein the motor pump unit (2) is activated based on measured, calculated and / or stored state data of the electric traction drive and the rotational direction (A, B) is adjusted based on a detected vehicle operating mode (1000, 2000, 3000, 4000), thereby adjusting the pump operating mode and the pump speed.

2. The method according to claim 1, It is characterized in that The vehicle operating mode (1000, 2000, 3000, 4000) is selected by a vehicle driver or by automated selection via a control unit.

3. The method according to claim 1 or 2, It is characterized in that In addition to the passive pump operating mode of the motor pump unit (2), i.e., in addition to the pump stop mode in which the motor pump unit (2) is not running, at least three active pump operating modes can be set, i.e., a first pump operating mode in which the electric motor of the motor pump unit (2) is operated by means of speed regulation in the first rotational direction (A) of the electric motor, a second pump operating mode in which the electric motor of the motor pump unit (2) is operated by means of speed regulation in the second rotational direction (B), and / or a third pump operating mode in which the electric motor of the motor pump unit (2) is operated in reverse by means of speed regulation in the first rotational direction (A) and the second rotational direction (B).

4. The method according to claim 1, 2 or 3, It is characterized in that The motor pump unit (2) is adjusted into a pump operating mode based on temperature data of subcomponents (R, S, GBX, 13, 3) of the electric traction drive that are measured, calculated and / or stored for the respective vehicle operating mode (1000, 2000, 3000, 4000).

5. The method according to claim 4, It is characterized in that When approaching and / or exceeding and / or falling below at least one limit value defined for the corresponding subcomponents (R, S, GBX, 13, 3) of the electric traction drive, a cooling and / or heating requirement is determined for each of the subcomponents and a total cooling and / or heating requirement is calculated, wherein the rotation direction (A, B) is adjusted based on the total cooling and / or heating requirement, thereby adjusting the pump operating mode and the pump speed.

6. The method (100) according to any one of claims 1 to 5, It is characterized in that When actively cooling and / or heating and / or lubricating the electric traction drive, an actual total volume flow of the fluid in the hydraulic device (1) is determined and compared with a defined desired total volume flow, wherein, when the actual total volume flow deviates from the desired total volume flow for a defined period of time, the motor pump unit (2) is adjusted to operate alternately in the first rotational direction (A) and in the second rotational direction (B) at maximum pump speed, and this is repeated until the actual total volume flow no longer deviates from the desired total volume flow.

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