Drivetrain with automatic transmission or automated manual transmission, an oil supply and a hydrodynamic retarder, as well as methods for controlling the retarder.

Abstract

Drive train with automatic or automated manual transmission with an oil supply, comprising an oil sump (1) and a pump device (3, 4) for providing a supply pressure P0; with a hydrodynamic retarder (19), comprising a working chamber with an inlet (24) and an outlet (25) through which the retarder (19) can be supplied with oil from the oil circuit, with a pressure line (2, 12, 22, 32) for supplying pressurized oil to elements (17, 18, 20) of the transmission; with valves (8, 9) in the pressure line (2, 12, 22, 32), with a heat exchanger (33) in the pressure line (2, 12, 22, 32) to dissipate heat from heated oil;with a retarder oil circuit (23) which can be connected to the heat exchanger (33) by means of a first valve (8) upstream of the heat exchanger (33) and a second valve (9) downstream of the heat exchanger (33), characterized in that valves (6, 7b, 8, 9, 27, 38, 39, 40) and a filling line (26, 41) are provided for controlling the hydrodynamic retarder (19), wherein the retarder oil circuit (23) can be connected to the pressure line (2, 12, 22, 32) via the filling line (26, 41) such that a retarder control pressure PR in the retarder oil circuit (23) can be variably adjusted, wherein a first pressure compensator (7b) and a second pressure compensator (27) are provided for controlling the retarder control pressure PR, wherein the filling line (41, 26) upstream of the first pressure compensator (7b) is connected to the pressure line (12) is connected and the second pressure balance (27) is arranged in the filling line (41, 26).

Description

[0001] The present invention relates to a drive train with an automatic transmission or automated manual transmission, an oil supply and a hydrodynamic retarder, and a method for controlling a hydrodynamic retarder in a drive train with a corresponding oil supply in order to adjust the degree of filling and / or the pressure in the working chamber of the hydrodynamic retarder depending on a requested retarder braking torque.

[0002] Powertrains with an automatic or automated manual transmission require an oil supply to selectively pressurize the shifting elements, thereby enabling different shift stages or gears within the transmission and thus different gear ratios between the transmission input shaft and output shaft. In addition to the shifting elements, the lubrication of components such as bearings must be ensured. Furthermore, such an oil supply system can incorporate a hydrodynamic retarder and a hydrodynamic torque converter as a starting element, which operate using oil from the transmission's oil supply.

[0003] Such an oil supply system with retarder and converter is known, for example, from DE 199 09 690 A1 or DE10 2009 035 082 A1. The design of these oil supplies is quite complex and requires sophisticated valve control.

[0004] In particular, the control and cooling of the hydrodynamic retarder, which has a bladed primary wheel and a bladed secondary wheel that together form a working chamber that can be filled with the working medium in order to form a hydrodynamic circulating flow in the working chamber when it is more or less filled with a working medium and thereby transfer torque from the primary wheel to the secondary wheel, thus hydrodynamically braking the primary wheel, has been found to have some disadvantages.

[0005] One of the objects of the present invention is to provide a drive train of the type mentioned above, as well as a method for controlling a corresponding hydrodynamic retarder in an oil supply, in which a high control quality of the hydrodynamic retarder is achieved.

[0006] Furthermore, the heat input into the oil sump during the activation and deactivation of the hydrodynamic retarder should be reduced.

[0007] The problem according to the invention is solved by a drive train with the features of claim 1 and a method with the features of claim 12. Advantageous and particularly expedient embodiments of the invention are specified in the dependent claims.

[0008] The drive train according to the invention, with automatic transmission or automated manual transmission, has an oil supply comprising an oil sump and a pump device for providing a supply pressure P0, and a hydrodynamic retarder. The retarder includes a working chamber with an inlet and an outlet through which the retarder can be supplied with oil from the oil circuit.

[0009] Furthermore, the oil supply system includes a pressure line through which the transmission components are supplied with pressurized oil from the pressure oil supply. Valves and at least one heat exchanger are provided in the pressure line. Valves upstream and downstream of the heat exchanger can be switched in such a way that the heat exchanger can be connected to a retarder oil circuit.

[0010] It is proposed that valves and a filling line be provided for the control of the hydrodynamic retarder, wherein the retarder oil circuit can be connected to the pressure line via the filling line in such a way that a retarder control pressure P is achieved. R is variably adjustable in the retarder oil circuit.

[0011] This arrangement results in a higher control quality of the retarder, since the control valves and the filling line can be dimensioned relatively small, as only relatively small volume flows are passed through them.

[0012] The large volume of oil circulating in the retarder oil circuit and through the heat exchanger during braking does not need to circulate through the retarder control valves. Furthermore, the retarder control valves are not exposed to the high temperature fluctuations present in the retarder oil circuit, so the control conditions remain relatively constant.

[0013] The pumping device generates an oil flow with a supply pressure P 0, The transmission's switching elements, such as shift elements, clutches, and / or brakes (e.g., multi-plate clutches), can be actuated. This allows for the selection of one of several possible gear ratios between a transmission input shaft and a transmission output shaft.

[0014] Furthermore, the pressure line can be divided into sections by the valves in the direction of flow, whereby the supply pressure P0 can be regulated by means of the valves in the sections to at least a first working pressure P1, and subsequently to a second working pressure P2, where P0 > P1 > P2 applies.

[0015] It is advantageous if the valves are switchable and controllable in such a way that, in every operating state of the drive train, a flow of lubricating oil can be pumped from the oil sump through the pressure line to a lubricating oil supply.

[0016] The operating conditions mainly include starting operation with torque converter, driving operation with locked torque converter, lock-up operation and braking operation, but also the operating conditions of the other components of the drivetrain such as the engine, etc.

[0017] In different versions, a control valve and / or a pressure relief valve can be provided to regulate the lubricating oil pressure P3 in a further, a third section of the pressure line, where P3 < P2.

[0018] Furthermore, the third section of the pressure line can be connected to the suction side of a pump in the pumping device via the control valve and a bypass line. Depending on the operating conditions, the oil, which may still be heated, is pumped directly back into the pressure line via the bypass line, thus reducing the heat input into the oil sump.

[0019] In one version, the retarder control pressure P can be regulated. RA 4 / 3 control valve is provided, through which the filling line can be connected to the pressure line. This control valve is switched simultaneously with the valves upstream and downstream of the heat exchanger via a common control valve, using the same switching pressure. The switching occurs with a time delay or in a controlled manner due to the different switching pressures.

[0020] In a further version, the retarder control pressure P can be regulated. R A first pressure compensator and a second pressure compensator are provided, wherein the filling line is connected to the pressure line upstream of the first pressure compensator and the second pressure compensator is located in the filling line. During operation, the working pressure P1 is controlled by a first control valve using the first pressure compensator, and the retarder control pressure P is controlled by a second pressure compensator using the second pressure compensator, controlled by a second control valve. R regulated.

[0021] In particular, the second pressure compensator can be structurally optimized for the control and requirements of the retarder used, thus improving controllability. Furthermore, the temperature gradients at the pressure compensator are lower, and the first pressure compensator can take over the function of the second in the event of a failure and adjust the retarder pressure P accordingly. R regulate so that the first working pressure P1 is simultaneously the retarder control pressure P R is.

[0022] Furthermore, the first and second valves, which connect the retarder oil circuit to the heat exchanger and are located upstream and downstream of it, can be switched via a third control valve using a control pressure. The switching pressure of the first valve is lower than that of the second valve. Due to the different valve designs, the valves switch with a time delay, so that when switching from braking to non-braking operation, the heated oil from the retarder's working chamber flows through the heat exchanger for a slightly longer time, thus reducing the amount of heated oil entering the oil sump.

[0023] Furthermore, a hydrodynamic converter can be provided in the pressure line, downstream of the retarder's switching valve, as a starting element. This converter forms a section of the pressure line, and its control is achieved via a valve located downstream of the converter. The converter and a second heat exchanger, preferably located upstream in the pressure line, are thus subjected to flow in all operating conditions, ensuring that the oil is cooled from the oil sump even during extended retarder operation.

[0024] In lockup operation and in converter operation, the oil is cooled via two heat exchangers, whereby the heat exchanger in front of the converter can be designed to be significantly smaller.

[0025] In a further advantageous embodiment, the retarder inlet can be connected to the lubricating oil supply via an oil line and the retarder control valve. Such a connection can be used to cool the retarder with small quantities of oil, also known as injector oil, when not in braking mode, thus reducing power loss. This connection has the further advantage that the fill line is always filled with oil, significantly reducing the retarder's response time.

[0026] A method according to the invention for controlling a hydrodynamic retarder in a drive train with a corresponding oil supply has the following essential advantages. The retarder oil circuit is first closed and then filled with relatively cold oil from the oil sump, which allows the oil to dissipate more braking energy initially. Furthermore, when switching to non-braking mode, the staggered switching of the valves upstream and downstream of the heat exchanger results in less heated oil being discharged from the retarder circuit into the oil sump.

[0027] The invention will be described below by way of example with reference to embodiments and the figures.

[0028] They show:

[0029] Fig. 1 a schematic representation of a motor vehicle drive train according to the invention;

[0030] Fig. 2. a design of the oil supply of a gearbox, in particular a motor vehicle gearbox;

[0031] Fig. 3 another design of the oil supply of a gearbox, in particular a motor vehicle gearbox;

[0032] In the Fig. Figure 1 schematically depicts a corresponding drivetrain with an internal combustion engine. 45 , the gearbox 50 and the drive wheels 49 It is also shown as an optional feature: an electric machine. 46 shown to form a hybrid vehicle powertrain. With the electric machine 46 The drive wheels can also be 49 be powered.

[0033] In addition, the oil sump 1 in the gearbox 50 indicated, as well as a first oil pump 3 and a second oil pump 4 with their electric drive motor 4 Furthermore, the switching elements 17 for setting different gear ratios between a transmission input shaft 47and a transmission output shaft 48 hinted at.

[0034] The retarder and the torque converter are not shown separately, although these are also coupled to the gearbox or housed within the gearbox casing.

[0035] In the Fig. 2 and Fig. Figure 3 shows two embodiments of how the oil supply of an automatic transmission or automatic manual transmission can be implemented. The embodiments also illustrate different pump devices for the oil supply with regard to the basic arrangement of the pumps. To achieve particularly efficient pump operation, a first oil pump driven by the internal combustion engine is shown here. 3 and a second one, powered by an electric drive 5 driven oil pump 4 The oil pump was used. 3 However, it can also be designed in such a way that one pump is sufficient.

[0036] The interconnection and control of the two oil pumps 3 , 4 can, as in Fig. 1 and Fig. The two images shown may be designed differently. From the oil sump 1 Oil is transported via an oil pipeline 30 , 31a , b into the pressure line 2 , 12 , 22 , 32 This is promoted by appropriate switching and control of the valves. 6 , 7 , 8 , 9 , 10 It is ensured that in front of the valve 6 a supply pressure P0 is adjustable and behind the valve 6 There is always an oil flow with an adjustable oil pressure through the pressure line. 2 , 12 , 22 , 32 and the valves 7 , 8 , 9 , 10 up to the lubrication points 20 can be reached.

[0037] The pressure line is divided into sections by the valves. 2 ,12 , 22 , 32 divided, whereby the supply pressure P0 is controlled by the valves 6 , 7 , 8 , 9 , 10 , 27 in the subsections is adjustable to at least a first working pressure P1, and subsequently to a second working pressure P2, where P0 > P1 > P2.

[0038] The supply pressure P0 in the pressure line section 2 is via the working pressure valve 6 , which is achieved by means of the switching valve 38 The switching process is regulated.

[0039] From the pressure pipe section 2 branches off the oil supply for the switching elements 17 from, whereby the individual switching elements 17 via lines 16 and the switching and control valves 15 They are supplied with pressurized oil. The switching elements, not shown in detail here, 17 These could be clutches or brakes, which are actuated via pressurized oil.

[0040] To the subsection 32 Finally, it's about lubrication. 20 connected, with the control valve P3 being used to regulate the lubricating oil pressure 11 and / or the pressure relief valve 51a can be used.

[0041] Furthermore, in both versions, the converter is a section within the pressure line. 2 , 12 , 22 , 32 This means that the torque converter is always permeated by an oil flow at oil pressure P2, regardless of whether it is actively used as a starting element or not. Before the torque converter 18 is the heat exchanger 21 arranged.

[0042] Pressure regulation is generally achieved using appropriate switching and control valves. 29 , 34 , 38 , 39 , 40 including sensors 36 , 37 may be provided for.

[0043] The retarder is also integrated into the oil circuit in both versions in the same way, based on its basic concept. This includes the valves. 8 and 9 provided for, which in a switching position the heat exchanger 33 into the retarder oil circuit 23 to integrate so that, during braking operation, the oil heated by the braking power in the retarder working chamber can be cooled in the heat exchanger.

[0044] The retarder is controlled via the filling line. 26 , 41 , which is connected to the pressure line in the subsection 12 is connectable.

[0045] In Fig. Figure 2 shows a first variant for the retarder control. The valves are used for braking operation. 7 , 8 and 9 switched via a switching pressure that is controlled by the switching and control valve 40 It is controlled / regulated. This affects the heat exchanger. 33 into the retarder oil circuit 23integrated and the oil for the lubricating oil supply 20 It is directly, only through the heat exchanger. 21 cooled, through the pressure line 32 guided.

[0046] The retarder working chamber is filled via the filling line. 26 , by the 4 / 3 control valve 7 The system is switched accordingly. The regulation of the retarder pressure P R This also occurs via the control valve 7 , whereby the switching points of this control valve are designed accordingly.

[0047] When switching to non-braking mode, the valves 7 , 8 , 9 via a control pressure of switching and control valve 40 They are switched in the following sequence. First, the control valve is switched. 7 switched to the starting position, then valves 9 and finally, valve 8 The delayed switching of the valves 8 and 9When the engine is switched off, the heated oil from the working chamber passes through the heat exchanger for a moment. 33 is directed from there via the pressure relief valve 51a into the oil swamp 1 It has arrived. As soon as the valve is also 8 When the switch is activated, the remaining oil content is drawn from the working chamber and the retarder oil circuit. 23 uncooled into the oil sump 1 is being pumped.

[0048] In Fig. Figure 3 shows a second variant for retarder control. Here too, the valves are used for brake operation. 8 and 9 in the already to Fig. switched in the manner described in section 2.

[0049] The regulation of the retarder is different here. 19 about the control of the valves 7b and 27 These valves are designed as pressure balances, which are controlled via the switching and control valves. 38 , 39They can be switched. This allows the valves to be switched. 8 and 9 from the circuit of the pressure balances 7b and 27 decoupled. The return spring of the pressure balance. 27 This allows it to be designed with a lower sensitivity, thereby increasing the resolution of the valve and thus the sensitivity of the retarder control.

[0050] To shorten the response / filling time of the retarder 19 is another oil pipeline, injection pipeline 44 , provided for. By "impregnating" the retarder's working chamber with oil, the retarder's power loss during non-braking operation can be reduced. The pressure balance can be used for this purpose. 27 via the control valve 39 to be switched so that a connection between the pressure line 32 and the filling line 26 The inoculation oil volume is created via the throttle. 52 in the vaccination line 44 adjusted and the injection oil pressure via the throttle51b The filling line thus remains full at all times and does not need to be refilled when switching to braking mode.

[0051] The bypass line 42 connects the pressure line 32 via the valve 11 directly with the intake side of the oil pump 3 This reduces unnecessary heat input into the oil sump.

[0052] In a branch from the pressure line 2 It also has a safety valve 29 It is designed to open above a predetermined pressure value. Both versions also show additional components, which will not be discussed in detail here, as they are generally known to those skilled in the art and their function is clearly evident from the circuit diagrams. These include, in particular, the check valves. 28 , or the pressure relief valves 51 , the sensors 36 , 37 , as well as the unmentioned valves, filters 13 / 14, etc. QUOTES INCLUDED IN THE DESCRIPTION

[0053] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0054] DE 19909690 A1

[0003] DE 102009035082 A1

[0003]

Claims

[1] Powertrain with automatic transmission or automated manual transmission 1.1 with an oil supply, comprising an oil sump ( 1 ) and a pumping device ( 3 , 4 ) to provide a supply pressure P0; 1.2 with a hydrodynamic retarder ( 19 ), having a workspace with an entrance ( 24 ) and an outlet ( 25 ), via which the retarder ( 19 ) can be supplied with oil from the oil circuit, 1.3 with a pressure line ( 2 , 12 , 22 , 32 ) for the pressure oil supply of elements ( 17 , 18 , 20 ) of the gearbox; 1.5 with valves ( 8 , 9 ) in the pressure line ( 2 , 12 , 22 , 32 ), 1.6 with a heat exchanger ( 33 ) in the pressure line ( 2 , 12 , 22 , 32) to remove heat from heated oil; 1.7 with a retarder oil circuit ( 23 ), which uses a valve ( 8 ) before the heat exchanger ( 33 ) and a valve ( 9 ) behind the heat exchanger ( 33 ), which can be connected to it, characterized by that for the control of the hydrodynamic retarder ( 19 ) Valves ( 6 , 7a , 7b , 8 , 9 , 27 , 38 , 39 , 40 ) and a filling line ( 26 , 41 ) are provided, whereby the retarder oil circuit ( 23 ) via the filling line ( 26 , 41 ) such with the pressure line ( 2 , 12 , 22 , 32 ) is connectable, that a retarder control pressure P R in the retarder oil circuit ( 23 ) is variably adjustable. [2] Powertrain according to claim 1, characterized bythat the pressure line ( 2 , 12 , 22 , 32 ) viewed in the direction of flow through the valves ( 6 , 7a , 7b , 8 , 9 , 10 , 11 ) is divided into sections, whereby the supply pressure P0 is controlled by the valves ( 6 , 7a , 7b , 8 , 9 , 10 , 11 ) in the subsections is adjustable to at least a first working pressure P1, and subsequently to a second working pressure P2, where P0 > P1 > P2. [3] Powertrain according to claim 1, characterized by that the valves ( 6 , 7a , 7b , 8 , 9 , 10 , 11 ) are switchable and controllable in this way, that in every operating state of the drivetrain a lubricating oil flow from the oil sump ( 1 ) through the pressure line ( 2 , 12 ,22 , 32 ) up to a lubricating oil supply ( 20 ) is pumped. [4] Drive train according to claim 3, characterized in that a control valve ( 11 ) and / or a pressure relief valve ( 51a ) is / are intended to be used in a further section of the pressure line ( 32 ) to regulate the lubricating oil pressure P3, where P3 < P2. [5] Powertrain according to claim 4, characterized by that the subsection ( 32 ) the pressure line via the control valve ( 11 ) and a bypass line ( 42 ) with the suction side of a pump ( 3 ) the pumping device ( 3 , 4 ) is connectable. [6] Powertrain according to claim 1, characterized by that to regulate the retarder control pressure P R a 4 / 3 control valve ( 7a ) is provided for, via which the filling line ( 26 ) with the pressure line ( 12 ) is connectable, whereby the control valve ( 7a) simultaneously with the valves ( 8 , 9 ), by means of the same switching pressure, controlled by a common control valve ( 40 ), is switched on. [7] Powertrain according to claim 1, characterized by that to regulate the retarder control pressure P R a first pressure balance ( 7b ) and a second pressure balance ( 27 ) are provided, with the filling line ( 41 , 26 ) before the first pressure balance ( 7b ) with the pressure line ( 12 ) is connected and the second pressure balance ( 27 ) in the filling line ( 41 , 26 ) is arranged. [8] Powertrain according to claim 7, characterized by that the retarder control pressure P R using the pressure balance ( 27 ), controlled by a control valve ( 39 ), in the filling line ( 41 , 26 ) is regulated and the first working pressure P1 is set by means of the pressure balance ( 7b), controlled by a control valve ( 38 ), is regulated. [9] Powertrain according to claim 1, characterized by that the first valve ( 8 ) and the second valve ( 9 ), which connect the retarder oil circuit ( 23 ) with the heat exchanger ( 33 ) are arranged in front and behind this, via a control valve ( 40 ) are switched by means of a control pressure, whereby the switching pressure of the first valve ( 8 ) is lower than that of the second valve ( 9 ). [10] Powertrain according to claim 2 or 3, characterized by that in the pressure line ( 2 , 12 , 22 , 32 ), viewed in the direction of flow behind the valve ( 7a , 7b ), a hydrodynamic converter ( 18 ) is provided as a starting element that covers a section of the pressure line ( 22 ) forms, whereby the control of the hydrodynamic converter ( 18) by means of the valve ( 10 ). [11] Powertrain according to claim 3 or 4, characterized by that the entrance ( 24 ) of the retarder ( 19 ) via an oil pipeline ( 44 ) and the retarder control valve ( 27 ) with the subsection ( 32 ) the pressure line and thus connectable to the lubricating oil supply. [12] Method for controlling a hydrodynamic retarder ( 19 ) in a drive train with an oil supply according to any one of claims 1 to 11, comprising the following steps: 12.1 when switching on the hydrodynamic retarder ( 19 ), integrating the heat exchanger ( 33 ) into the retarder oil circuit ( 23 ) by switching the valves ( 8 , 9 ); and filling the retarder's working chamber with oil via the control line ( 26 , 41 ), by switching the valves ( 7a , 7b , 27 ) 12.2 In retarder brake operation, setting a predetermined retarder oil pressure P R in the working space of the hydrodynamic retarder ( 19 ) depending on a requested retarder braking torque by means of the valve ( 7a , 27 ); 12.3 when switching off the hydrodynamic retarder ( 19 ), staggered switching of the valves ( 8 , 9 , 7a , 27 ), where first the valve ( 7a , 27 ), to close the filling line ( 26 ), and then valve ( 9 ) are switched on so that the oil is removed from the retarder oil circuit ( 23 ) further via the heat exchanger ( 33 ) is directed and then, by switching the valve ( 8 ), directly into the oil sump ( 1 ) is taken away.

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