Abstract: A vehicle transmission includes a hydraulic circuit and a control unit. The control unit is configured to: obtain (20) a target pressure specification; convert (26) the target pressure specification into a target volume flow rate; determine (42) a valve volume flow rate as a function of the target volume flow rate and as a function of parameters that represent system properties of the hydraulic circuit; determine (46) a pressure drop at a valve due to flow forces as a function of the valve volume flow rate; determine (48) a compensated valve output pressure as a function of the valve volume flow rate and the pressure drop; determine (58) the electric control current as a function of the compensated valve output pressure; and activate a valve with the electric control current.

Abstract: A vehicle transmission includes a hydraulic circuit and a control unit. The control unit is configured to: obtain (20) a target pressure specification; convert (26) the target pressure specification into a target volume flow rate; determine (42) a valve volume flow rate as a function of the target volume flow rate and as a function of parameters that represent system properties of the hydraulic circuit; determine (46) a pressure drop at a valve due to flow forces as a function of the valve volume flow rate; determine (48) a compensated valve output pressure as a function of the valve volume flow rate and the pressure drop; determine (58) the electric control current as a function of the compensated valve output pressure; and activate a valve with the electric control current.

Abstract: A transmission (G) includes an input shaft (GW1), an output shaft (GW2), an electric machine (EM), a plurality of planetary gear sets (P1-P3; 2P1-2P5), and gear-implementing shift elements (S1-S6; 2S1-2S5). Via engagement of a first of the gear-implementing shift elements (S1, 2S1), which is a force-locking shift element having a variable torque transmission capacity, the input shaft (GW1) and an element (E1, 22E1) of one of the planetary gear sets (P3; 2P4) can be brought into a fixed rotational speed relationship with respect to each other. Another element (E2, 22E2a, 22E2b) of one of the planetary gear sets (P1, 2P3, 2P5) is permanently connected to a rotor (R) of the electric machine (EM). By engaging an auxiliary shift element (ZS, 2ZSa, 2ZSb), which is a form-locking shift element, the rotor (R) and the input shaft (GW1) can be brought into a fixed rotational speed relationship with respect to each other.

Abstract: A transmission (G) includes an input shaft (GW1), an output shaft (GW2), an electric machine (EM), a plurality of planetary gear sets (P1-P3; 2P1-2P5), and gear-implementing shift elements (S1-S6; 2S1-2S5). Via engagement of a first of the gear-implementing shift elements (51, 2S1), which is a force-locking shift element having a variable torque transmission capacity, the input shaft (GW1) and an element (E1, 22E1) of one of the planetary gear sets (P3; 2P4) can be brought into a fixed rotational speed relationship with respect to each other. Another element (E2, 22E2a, 22E2b) of one of the planetary gear sets (P1, 2P3, 2P5) is permanently connected to a rotor (R) of the electric machine (EM). By engaging an auxiliary shift element (ZS, 2ZSa, 2ZSb), which is a form-locking shift element, the rotor (R) and the input shaft (GW1) can be brought into a fixed rotational speed relationship with respect to each other.

Abstract: A transmission for a motor vehicle wherein the drive shaft (An) is rotationally fixedly connectable by the first shift element (K1) to the first shaft (1) and by the second shift element (K2) to the second shaft (2). The second shaft (2) is rotationally fixedly connectable by the fifth shift element (B2) to the housing (3). The third shaft (4) is rotationally fixedly connected to the third gear set element of the second planetary gear set (RS2) and to the first gear set element of the third planetary gear set and is rotationally fixedly connectable by the sixth shift element (B1) to the housing (3). The second gear set element of the third planetary gear set (RS3) is rotationally fixedly connected to the output shaft (Ab), and the third gear set element of the third planetary gear set (RS3) is rotationally fixedly connected to the second shaft (2).

Abstract: A transmission for a motor vehicle wherein the drive shaft (An) is rotationally fixedly connectable by the first shift element (K3) to the first shaft (1) and the first shaft is rotationally fixedly connectable by the second shift element (B2) to the housing (2). A sun gear of the first planetary gear set (RS1) is rotationally fixedly connectable by the third shift element (K2) to the drive shaft (An). A carrier of the first planetary gear set (RS1) is rotationally fixedly connected to the output shaft (Ab) and to a ring gear of the second planetary gear set (RS2). A ring gear of the first planetary gear set (RS1) is rotationally fixedly connected to the second shaft (3), wherein the second shaft (3) is rotationally fixedly connectable by the fourth shift element (B1) to the housing (2).

Abstract: A transmission for a motor vehicle wherein the drive shaft (An) is rotationally fixedly connectable by the first shift element (K3) to the first shaft (1) and the first shaft is rotationally fixedly connectable by the second shift element (B2) to the housing (2). A sun gear of the first planetary gear set (RS1) is rotationally fixedly connectable by the third shift element (K2) to the drive shaft (An). A carrier of the first planetary gear set (RS1) is rotationally fixedly connected to the output shaft (Ab) and to a ring gear of the second planetary gear set (RS2). A ring gear of the first planetary gear set (RS1) is rotationally fixedly connected to the second shaft (3), wherein the second shaft (3) is rotationally fixedly connectable by the fourth shift element (B1) to the housing (2).

Abstract: A transmission for a motor vehicle wherein the drive shaft (An) is rotationally fixedly connectable by the first shift element (K1) to the first shaft (1) and by the second shift element (K2) to the second shaft (2). The second shaft (2) is rotationally fixedly connectable by the fifth shift element (B2) to the housing (3). The third shaft (4) is rotationally fixedly connected to the third gear set element of the second planetary gear set (RS2) and to the first gear set element of the third planetary gear set and is rotationally fixedly connectable by the sixth shift element (B1) to the housing (3). The second gear set element of the third planetary gear set (RS3) is rotationally fixedly connected to the output shaft (Ab), and the third gear set element of the third planetary gear set (RS3) is rotationally fixedly connected to the second shaft (2).

Abstract: A method for operating a drive train of a motor vehicle includes closing a frictional-locking shift element that serves as a starting element of a transmission in a slipping manner such that slip at the frictional-locking shift element is reduced by a defined pressure control of the frictional-locking shift element, determining a differential rotational speed at the frictional-locking shift element or a variable dependent on the differential rotational speed while the frictional-locking shift element is closing, and, when the differential rotational speed or the variable dependent on the differential rotational speed is less than a first limit value or reaches the first limit value, changing a rotational speed of the drive unit in such a manner that the differential rotational speed or the variable dependent on the differential rotational speed becomes less than a second limit value or reaches the second limit value within a defined time period.

Abstract: A method for operating a drive train of a motor vehicle includes closing a frictional-locking shift element that serves as a starting element of a transmission in a slipping manner such that slip at the frictional-locking shift element is reduced by a defined pressure control of the frictional-locking shift element, determining a differential rotational speed at the frictional-locking shift element or a variable dependent on the differential rotational speed while the frictional-locking shift element is closing, and, when the differential rotational speed or the variable dependent on the differential rotational speed is less than a first limit value or reaches the first limit value, changing a rotational speed of the drive unit in such a manner that the differential rotational speed or the variable dependent on the differential rotational speed becomes less than a second limit value or reaches the second limit value within a defined time period.

Abstract: A method of operating a vehicle hybrid drive-train in which, depending on the operating situation, the engine and electric machine either operate individually or together. The engine and the electric machine can be coupled or separated by a clutch. The engine can be started by the electric machine or a separate starting device. To co-ordinate transmission shifts and required engine starts, during a transmission shifting process, if the engine needs to be started, then based on whether the shift is an upshift, a downshift, a traction shift or an overdrive shift and also depending on the type of engine start required, it is first determined whether the shift should be completed, at least partially completed or discontinued before carrying out the start and, based on this determination, measures for continuing, at least partially continuing or discontinuing the shift process are initiated.

Abstract: A multi-disk shifting element of a motor vehicle transmission, which includes a plurality of outer disks (2) and a plurality of lining disks (1) which, when viewed axially, are arranged in alternation one after another. The outer disks include a number of flat outer disks (AL1) and a number of corrugated outer disks (AL2, AL3).

Abstract: A method of operating a vehicle hybrid drive-train in which, depending on the operating situation, the engine and electric machine either operate individually or together. The engine and the electric machine can be coupled or separated by a clutch. The engine can be started by the electric machine or a separate starting device. To co-ordinate transmission shifts and required engine starts, during a transmission shifting process, if the engine needs to be started, then based on whether the shift is an upshift, a downshift, a traction shift or an overdrive shift and also depending on the type of engine start required, it is first determined whether the shift should be completed, at least partially completed or discontinued before carrying out the start and, based on this determination, measures for continuing, at least partially continuing or discontinuing the shift process are initiated.

Abstract: A pressure medium supply device of a hydraulically actuated shifting element (K1, K2) comprises at least one pressure medium supply duct (1, 2) in communication with a pump (4) and a line (3) for pre-filling of the shifting element. An additional pressure-retaining valve (9, 9?) or a check diaphragm is integrated in the pressure medium supply duct (1, 2), between the shifting element and the shifting element valve (6, 7), and can be closed in the draining direction of the pressure medium supply duct (1, 2). The pressure-retaining valve (9, 9?) is designed such that the shifting element can be drained and the pressure medium supply device can be vented.

Abstract: A hydraulic control system for controlling a variable fluid volume flow to a consumer (6, 60, 94, 126, 146, 162), for example a flow of cooling oil to a wet-operating clutch, with a hydraulically pilot-controlled control valve connected to a fluid supply. The first control valve (2, 56, 90, 122, 142) is designed such that, in the absence of any pilot control pressure (pVST), the valve delivers a specified initial volume flow (Q1) and, as the variable pilot control pressure (pVST) increases, the valve delivers a continuously increasing volume flow (QK). At least one second, independent, also hydraulically pilot-controlled valve (170) is designed such that this valve is activated in a specified range (55, 88, 120, 132, 140, 152) of the variable pilot control pressure (pVST).

Abstract: A pressure medium supply device of a hydraulically actuated shifting element (K1, K2) comprises at least one pressure medium supply duct (1, 2) in communication with a pump (4) and a line (3) for pre-filling of the shifting element. An additional pressure-retaining valve (9, 9?) or a check diaphragm is integrated in the pressure medium supply duct (1, 2), between the shifting element and the shifting element valve (6, 7), and can be closed in the draining direction of the pressure medium supply duct (1, 2). The pressure-retaining valve (9, 9?) is designed such that the shifting element can be drained and the pressure medium supply device can be vented.

Abstract: A hydraulic control device with a plurality of gear-actuating cylinders for engaging and disengaging the gears of an automated multi-step transmission, with pressure-controlled gear-regulating valves for controlling the pressure in one pressure chamber of the cylinders, and with a multiplex arrangement of singly switchable pressure-controlled selector valves for assigning the regulating valves to one pressure chamber of the actuating cylinders. The device includes a common pilot valve, designed as a regulating valve, for actuating one of the regulating valves and at least one of the selector valves. The pilot valve features a first control pressure range that contains the switching pressure of the selector valve and a second control pressure range that contains the regulating range of the gear-regulating valve.

Abstract: A method for operating a hydraulic device (1) of a transmission device having a variable displacement pump (2) that can be supplied with a hydraulic pressure (p_B) in order to vary the output in the area of an adjusting device (3), and having at least two pressure circuits (PK, SK) that can be connected to a discharge side (24) of the adjustable displacement pump (2) and are assigned different priorities with regard to the supply of hydraulic fluid by the pump. When a change is needed to the operating state of the transmission device for the implementation of which the output of the variable displacement pump (2) must be elevated relative to its current output, a pressure (p_B) applied in the region of the adjusting device (3) by a pressure return (5) is correspondingly modified before changing the operating state.

Abstract: A method for emergency actuation of an automated dual-clutch transmission of a vehicle with electrohydraulic control via a transmission control device. The method includes disengaging one clutch of the dual-clutch transmission, in order to realize emergency operation of the transmission and applying pressure on the other clutch after an error signal is transmitted indicating a malfunction of the transmission and/or the transmission control device. In order to keep the complexity of the hardware of the hydraulic system low, both clutches are disengaged, when an error signal occurs, and adjusted to a safe initial state, and an actuating pressure is only re-applied to one of the two clutches after the initial state is reached. In addition to the already existing elements of the hydraulic system, only one device or software is required which detects and selects the clutch that is more advantageous for continued driving operation.

Abstract: A bypass valve for a cooler connected downstream from a hydraulic aggregate. The bypass valve includes a housing with ports for connection to the hydraulic aggregate and the cooler. A closure element is located in the housing for closing and opening a bypass. A spring pushes the closure element into a closing position, and thermo-sensitive means causes the closure element to open if the temperature of the hydraulic fluid is below a threshold temperature. The thermo-sensitive means are formed by the valve spring, which is made of a memory-metal alloy with a transition point close to the threshold temperature such that below the threshold temperature it no longer exerts a force and allows the closure element to open.