Method and control unit for operating a motor vehicle

Abstract

Method for operating a motor vehicle with a drive unit (1), with a transmission (2) comprising four planetary gear sets (3, 4, 5, 6), five shift elements (9, 10, 11, 12, 13) and at least eight rotatable shafts (19, 20, 21, 22, 23, 24, 25, 26), and with an output (14), wherein the transmission (2) is designed as an automatic or automated transmission, is connected between the drive unit (1) and the output (14), and provides at least eight frictional forward gears and at least one frictional reverse gear by selectively closing and opening the shift elements (9, 10, 11, 12, 13), and wherein three of the five shift elements are designed as clutches (C, D, E) and two of the five shift elements are designed as brakes (A, B), wherein in each engaged frictional gear of the Transmission (2) a first number of switching elements (9, 10, 11, 12, 13) of the transmission (2) closed and a second number of switching elements (9, 10, 11, 12,13) of the transmission (2) is open, wherein, depending on at least one operating condition of the motor vehicle, a sailing mode is entered, wherein, to enter the sailing mode of the motor vehicle starting from a friction-based forward gear, a switching element of the transmission (2) is actuated to open, so that in a non-friction-based sailing gear one less switching element is closed and thus one more switching element is open than in a friction-based gear, wherein, in the sailing mode of the motor vehicle, the respective closed and open switching elements of the transmission (2) are changed depending on at least one operating condition of the motor vehicle to maintain the sailing gear, characterized in that, when starting from a fourth friction-based forward gear (V4), in which a switching element (10) designed as a brake (B) and two switching elements (12, 13) designed as clutches (D, E) are closed,When sailing mode is engaged, depending on the rotational speed at the output (14) or the rotational speed at a transmission output shaft (8), a non-frictional entry sailing gear (S4A, S4B) is engaged such that, if the rotational speed at the output (14) or at the transmission output shaft (8) is greater than a first limit value (G1), a first non-frictional entry sailing gear (S4A) is engaged such that one of the two switching elements (13) designed as clutches (E or D) is opened, so that in the non-frictional entry sailing gear (S4A) the switching element (10) designed as a brake (B) and one of the two switching elements (12) designed as clutches (D or E) are closed, a second non-frictional entry sailing gear is engaged if the rotational speed at the output (14) or at the transmission output shaft (8) is less than the first limit value (G1). (S4B) is inserted in this mannerthat the switching element (10) designed as a brake (B) is opened, so that in the non-force-locking entry sailing mode (S4B) the two switching elements (12, 13) designed as clutches (D, E) are closed.

Description

[0001] The invention relates to a method for operating a motor vehicle. Furthermore, the invention relates to a control unit for carrying out the method.

[0002] From DE 10 2005 002 337 A1, a transmission designed as an automatic or automated transmission is known, comprising four planetary gear sets, five shift elements, and at least eight rotatable shafts. By selectively opening and closing the shift elements, at least eight positive forward gears and at least one positive reverse gear can be provided. Three of the five shift elements are designed as clutches and two of the five shift elements as brakes.

[0003] German patent application DE 10 2011 005 320 A1 discloses a method for operating a motor vehicle comprising a drive unit, a transmission, and an output shaft, wherein the transmission is connected between the drive unit and the output shaft. The transmission is an automatic or automated manual transmission. According to DE 10 2011 005 320 A1, depending on at least one operating condition of the motor vehicle, a coasting mode is activated or entered, and subsequently, depending on at least one operating condition of the motor vehicle, the coasting mode is deactivated or exited.During the journey of the motor vehicle with the combustion engine running and coupled to the drive system, the sailing mode is activated when a driver-requested torque dependent on accelerator pedal operation or a driving torque specified by a driver assistance system remains within a defined range for a defined time and when the current acceleration or deceleration of the motor vehicle also remains within a defined range.

[0004] From DE 10 2010 000 857 A1, a further method for operating a motor vehicle is known. Details of a shifting sequence for disengaging a gear to enter sailing mode and details of a shifting sequence for engaging a gear to exit sailing mode are disclosed.

[0005] From DE10 2015 220 999 A1, it is known that when a sailing mode is entered, the closed and open switching elements of the transmission are adjusted or changed depending on at least one operating condition of the vehicle. This ensures that when exiting sailing mode, a suitable, friction-fit gear can be engaged in the transmission as quickly and smoothly as possible. Thus, when the closed and open switching elements are adjusted in sailing mode, a change from the current sailing gear to a target sailing gear occurs during sailing mode, with one more switching element being open in each sailing gear than in a friction-fit gear. To exit sailing mode, only one additional switching element of the transmission needs to be closed, starting from the current sailing gear, to engage a friction-fit gear in the transmission.

[0006] Currently, adjusting the sailing gear with sufficient comfort across all sailing gears is not possible. This is because switching elements designed as brakes are more sensitive, especially when closing, than switching elements designed as clutches, which can result in relatively long engagement times for a switching element designed as a brake. This is a disadvantage and impairs the comfort of adjusting sailing gears in the transmission. Based on this, the invention aims to create a novel method for operating a motor vehicle and a control unit for operating a motor vehicle.

[0007] This problem is solved by a method according to claim 1.

[0008] According to the invention, when starting from a fourth friction-locked forward gear in which a switching element designed as a brake and two switching elements designed as clutches are closed, a defined, non-friction-locked entry sailing gear is engaged depending on a speed at the output or depending on a speed at a transmission output shaft.

[0009] Then, when the rotational speed at the output shaft or at the transmission output shaft is greater than a first limit value, a first non-power-engaging entry coasting gear is engaged from the fourth power-engaging forward gear in such a way that one of the two switching elements designed as clutches is opened, so that in the first non-power-engaging entry coasting gear the switching element designed as a brake and closed in the fourth power-engaging forward gear and one of the two switching elements designed as clutches and closed in the fourth power-engaging forward gear are closed.However, if the rotational speed at the output shaft or the transmission output shaft is lower than the first limit, a second, non-power-engaged entry coasting gear is engaged from the fourth forward gear. This engages the brake-acting shift element, opening the second non-power-engaged entry coasting gear. In this second non-power-engaged entry coasting gear, the two clutch-acting shift elements, which are closed in the fourth forward gear, are closed. From these non-power-engaged entry coasting gears, which can be engaged from the fourth forward gear, coasting gears can be selected within the transmission with a high degree of comfort.

[0010] Following a further advantageous development, when the second non-friction-engaging entry-level sailing gear is engaged and the rotational speed at the output shaft or transmission output shaft subsequently falls below a second limit value, the sailing gear is adjusted. This adjustment is achieved by opening one of the two clutch-type switching elements that were closed in the second non-friction-engaging entry-level sailing gear, and closing another clutch-type switching element. Thus, in the new sailing gear, the clutch-type switching elements that were closed in the third friction-engaging forward gear are closed. The brake-type switching element that was closed in the third friction-engaging forward gear, however, is open in this new sailing gear.The adjustment of sailing gears in the gearbox is possible with a high degree of comfort, even subsequently, when the speed at the output or at the gearbox output shaft becomes less than a third limit value.

[0011] Following a further advantageous development, when the first non-friction-engaging sailing gear is engaged and the rotational speed at the output shaft or transmission output shaft exceeds a fifth limit value, the sailing gear is adjusted. This adjustment is achieved by opening the clutch-type shift element, which is closed in the first non-friction-engaging sailing gear, and closing another clutch-type shift element. Consequently, in the new sailing gear, the brake-type shift element, which is closed in the third, fourth, and fifth friction-engaged forward gears, and the clutch-type shift element, which is closed in the third and fifth friction-engaged forward gears but open in the fourth friction-engaged forward gear, are closed. Adjusting sailing gears within the transmission is highly convenient.

[0012] The control unit according to the invention is defined in claim 9.

[0013] Preferred embodiments are described in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. The drawing shows: Fig. 1 a powertrain diagram of a motor vehicle with a gearbox; Fig. 2 a shift matrix of the gearbox of the Fig. 1 with friction-fit threads; Fig. 3 a shift matrix of the gearbox of the Fig. 1 with non-force-locking sail gaiters; Fig. 4 one to Fig. 3 alternative, preferred shift matrix of the transmission Fig. 1 with non-force-locking sail gaiters; Fig. 5. A flowchart to illustrate the invention.

[0014] The invention relates to a method and a control unit for operating a motor vehicle and a control unit for carrying out the method.

[0015] Fig. Figure 1 shows a highly schematic representation of the powertrain of a motor vehicle with an automatic transmission. 2 .

[0016] The powertrain of the Fig. 1 includes a drive unit 1 , the automatic transmission 2 and a drive 14 , where the automatic transmission 2 between the drive unit 1 and the downforce 14 is switched on.

[0017] The basic structure and basic function of the gearbox 2 the Fig. 1 is known from DE 10 2005 002 337 A1.

[0018] The gearbox 2 includes a transmission input shaft 7 , a transmission output shaft 8 , four planetary gear sets 3 , 4 , 5, 6 and five switching elements 9 , 10 , 11 , 12 , and 13 , wherein the two switching elements 9 and 10 also as switching elements A and B are designated, and wherein the switching elements 11 , 12 and 13 also as switching elements C , D and E to be designated

[0019] Regarding the switching elements A and B as well as in the switching elements C , D and E These are all friction-fit switching elements, namely the switching elements A and B for brakes and switching elements C , D and E about couplings.

[0020] All four planetary gear sets 3 , 4 , 5 , 6They are designed as simple negative planetary gear sets and arranged coaxially one behind the other. A negative planetary gear set, as is known, has planet gears that mesh with the sun gear and ring gear of this planetary set.

[0021] The ring gears of the four planetary gear sets 3 , 4 , 5 , 6 are with HO3 , HO4 , HO5 and HO6 designated the sun wheels with SO3 , SO4 , SO5 and SO6 , the planetary gears with PL3 , PL4 , PL5 and PL6 , and the bridges on which the aforementioned planetary gears are rotatably mounted, with ST3 , ST4 , ST5 and ST6 .

[0022] With the five switching elements A until E is a selective shifting of eight forward gears V1 until V8 and at least one reverse gear R1 feasible. The gearbox 2has a total of at least eight rotatable shafts 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 on.

[0023] Regarding the coupling of the individual elements of the four planetary gear sets 3 , 4 , 5 , 6 among themselves and to the transmission input shaft 7 and transmission output shaft 8 is with the gearbox 2 The following is planned: The jetty ST4 of the planetary gear set 4 and the transmission input shaft 7 are connected to each other in a torsionally rigid manner and form a first shaft 19 of the gearbox 2 The footbridge ST6 of the planetary gear set 6 and the transmission output shaft 8 are connected to each other in a rotationally fixed manner and form a second shaft 20 of the gearbox 2 The sun wheel SO3 of the first planetary gear set 3 and the sun wheel SO4 of the planetary gear set 4 are connected to each other in a torsionally rigid manner and form a third shaft 21 of the gearbox 2 The ring gear HO3 of the planetary gear set 3 forms a fourth wave 22 of the gearbox 2 The ring gear HO5 of the planetary gear set 5 and the sun wheel SO6 of the planetary gear set 6 are connected to each other in a torsionally rigid manner and form a fifth shaft. 23 of the gearbox. The bridge ST3 of the planetary gear set 3 and the ring gear HO6 of the planetary gear set 6 are connected to each other in a torsionally rigid manner and form a sixth shaft. 24 of the gearbox 2 The sun wheel SO5 of the planetary gear set 5 and the ring gear HO4 of the planetary gear set 4 are connected to each other in a torsionally rigid manner and form a seventh shaft. 25 of the gearbox 2The footbridge ST5 of the planetary gear set 5 forms an eighth wave 26 of the gearbox 2 .

[0024] Regarding the coupling of the five switching elements 9 until 13 or A until E to the waves described so 19 until 26 of the gearbox 2 is with the gearbox 2 according to Fig. 1. The following is provided: A first switching element A is in the force flow between the third wave 21 and a gearbox housing 27 arranged. A second switching element B is in the force flow between the fourth wave 22 and the gearbox housing 27 arranged. A third switching element C is in the force flow between the fifth wave 23 and the first wave 19 arranged. A fourth switching element D is in the power flow between the eighth wave 26and the second wave 20 is arranged. A fifth switching element E is in the power flow between the seventh wave 25 and the fifth wave 23 arranged. The fourth switching element D Alternatively, the power flow can also alternate between the eighth wave and the eighth wave. 26 and the sixth wave 24 be arranged. The fifth switching element E The power flow can also alternatively switch between the fifth wave. 23 and the eighth wave 26 be arranged.

[0025] In Fig. 2 is a shift pattern of the gearbox. 2 according to Fig. 1 shown. In every positive-locking forward gear V1 until V8 Three switching elements are closed and two switching elements are open. The first forward gear V1 This results from closing the brakes. A and B and the clutch C , the second forward gear V2by closing the brakes A and B and the clutch E , the third forward gear V3 by closing the brake B and the couplings C and E , the fourth forward gear V4 by closing the brake B and the couplings D and E , the fifth forward gear V5 by closing the brake B and the couplings C and D , the sixth forward gear V6 by closing the couplings C , D and E , the seventh forward gear V7 by closing the brake A and the couplings C and D , as well as the eighth forward gear V8 by closing the brake A and the couplings D and E As can be seen from the shift diagram, reverse gear R is engaged by closing the brakes. A andB and the clutch D .

[0026] The relative position of the four plate gear sets 3 , 4 , 5 , 6 and the five switching elements A , B , C " D , E of the in Fig. 1 of the depicted gearbox 2 inside the gearbox 2 In principle, it can be arbitrary and is only determined by the dimensions and external shape of the gearbox housing. 27 limited. This is known from DE 10 2005 002 337 A1.

[0027] Fig. Figure 1 shows that the drive unit 1 to a transmission input shaft 7 and the downforce 14 to a transmission output shaft 8 is coupled. Depending on the transmission 2 The selected gear is converted by the transmission. 2 Speeds and torques, thus determining the tractive force available from the drive unit. 1 at the drive 14ready.

[0028] Between the drive unit 1 and the transmission input shaft 7 is in Fig. In the embodiment shown in 1, a converter 15 switched. Such a converter 15 has a turbine 16 , where the turbine 16 to the transmission input shaft 7 is coupled. Furthermore, it has a converter. 15 via a pump 17 and a torque converter lock-up clutch 18 The design of such a converter is familiar to the expert addressed here. Instead of a converter, a starting clutch can also be used between the drive unit. 1 and the transmission input shaft 7 be switched on.

[0029] Like the switching matrix of the Fig. 2 can be taken from each force-transmitting or friction-locking gear of the transmission. 2 a first defined number of switching elements 9 until 10closed or switched on and a second defined number of switching elements 9 until 13 opened or switched off. Fig. 2 can be seen that in each friction-fit gear three switching elements are closed and two switching elements are open.

[0030] It is already known that when in the gearbox 2 a positive gear is engaged and the motor vehicle is driving in this positive gear, depending on at least one operating condition of the motor vehicle, a sailing mode is entered, whereby a switching element of the transmission is used to enter sailing mode from a positive gear. 2 , which is closed in the friction-based gear, is controlled to open, so that in sailing mode one less switching element is closed and thus one more switching element is open than in a friction-based gear, so that the frictional connection in the transmission is then2 is interrupted. The transmission's switching elements 2 , which are closed in sailing mode, form a non-force-locking sailing gait.

[0031] Furthermore, it is already known that after entering a sailing mode, it is possible to exit sailing mode again depending on at least one operating condition of the vehicle. For this purpose, a switching element is closed from sailing mode to engage a positive gear. Should the drive unit be in sailing mode... 1 If it is stopped, the same thing will start when exiting sailing mode.

[0032] Furthermore, it is already known that in the sailing mode of the motor vehicle, the respective closed and open switching elements of the transmission 2The sailing gear can be adjusted or changed depending on at least one operating condition of the vehicle. This ensures that the non-power-engaged sailing gear is maintained during sailing mode. This adjustment of the sailing gear allows for a spontaneous and comfortable exit from sailing mode.

[0033] As already explained above, in every frictional gear of the transmission 2 a first number of switching elements 9 until 13 closed and a second number of switching elements 9 until 13 opened. Then, when the vehicle's sailing mode is active, only a single shift element of the transmission is engaged in sailing mode. 2more open than in a friction-locked gear. The switching elements that are closed in sailing mode define the so-called non-friction-locked sailing gear, from which a friction-locked gear can be closed to exit sailing mode.

[0034] While in the switching matrix of the Fig. 2 those in the respective positive-locking forward gear V1 until V8 as well as the switching elements closed in the positive-locking reverse gear R are marked with a dot, are in the switching matrix of the Fig. 3 and in the alternative switching matrix of the Fig. 4 for non-force-locking sailing gears S1 Up to S8B, those switching elements are marked with a dot which are closed in the respective sailing gear.

[0035] From the switching matrix of the Fig. 3 and the alternative switching matrix of the Fig. It follows again in section 4 that in each non-force-locking sailing gear, one more switching element is open than in a force-locking gear. The switching matrix of the Fig. 4 is preferred.

[0036] Then, starting from a fourth positive forward gear V4 , in which that acts as a brake B trained second switching element 10 and each of those as a coupling D , E trained fourth and fifth switching elements 12 , 13 Each is closed, and the sailing mode is entered depending on the rotational speed at the output. 14 or depending on the speed of the transmission output shaft 8 either a first non-force-locking entry sail S4A or a second non-force-locking entry sail passage S4B inserted.

[0037] The procedure is as follows: when the rotational speed at the output... 14or at the transmission output shaft 8 greater than a first limit G1 is the first non-force-locking entry sail S4A is inserted.

[0038] The first non-force-locking entry sail S4A is inserted in such a way that one of the two switching elements designed as clutches 12 , 13 , namely in the switching matrix of the Fig. 3 that as a clutch E trained fifth switching element 13 and in the preferred switching matrix of Fig. 4 that as a clutch D trained fourth switching element 12 , is opened so that in the non-force-locking first entry sailing gear S4A that acts as a brake B trained second switching element 10 and in the switching matrix of the Fig. 3 the other as a clutch D trained fourth switching element 12 or in the case of the preferred switching matrix of Fig. 4 the other as a clutch E trained fifth switching element 13 , both in fourth positive forward gear V4 are closed, are closed. In the flowchart of the Fig. 5 visualizes an arrow 28 entering sailing mode from the fourth forward gear V4 , whereupon, when the rotational speed at the output 14 or at the transmission output shaft 8 greater than the first limit G1 is, according to the arrow 29 the Fig. 5 the first non-force-locking entry sailing gear S4A inserted or the transmission 2 into this first non-force-locking entry sailing leg S4A is transferred. Fig. 5 are in the sailing gear S4A visualizing block for the switching matrix of the Fig. 3 and the switching matrix of Fig. 4 the respective closed switching elements are specified, namely for which the switching matrix of the Fig. 3 in parentheses.

[0039] However, if the entry condition is met 28 for entering sailing mode starting from the fourth forward gear with positive engagement V4 the rotational speed at the output 14 or at the transmission output shaft 8 smaller than the first limit G1 is, will be according to the arrow 30 the Fig. 5 a second non-force-locking entry sail S4B inserted or the transmission 2 starting from the positive-locking fourth forward gear V4 into the second non-force-locking entry sail passage S4B convicted, in such a way that it acts as a brake B trained second switching element 10 , which in the fourth positive forward gear V4is closed, is opened, so that then in the second non-force-locking entry sailing gear S4B the two as couplings D and E trained switching elements of the transmission 2 , that is, the fourth switching element 12 and the fifth switching element 13 , both in fourth positive forward gear V4 are closed, in the second non-force-locking entry sailing gear S4B are also closed.

[0040] Then, when the second non-force-locking entry sail passage S4B is inserted and subsequently the speed at the output 14 or at the transmission input shaft 8 smaller than a second limit G2 The sailing gear is adjusted accordingly, namely in such a way that a third positive forward gear is achieved. V3 suitable new sailing gear S3B is engaged, in such a way that the new sailing gear is ready. S3B one of the two in the second entry sailing gear S4B closed switching elements designed as couplings, namely the coupling D trained fourth switching element 12 is opened, and another switching element designed as a clutch, namely the one designed as a clutch C trained third switching element 11 is closed. In the new sailing gear S3B are then those in the third positive forward gear V3 closed, as couplings C and E trained switching elements, namely the third switching element 11 and the fifth switching element 13 , closed.

[0041] Should the rotational speed at the output subsequently change 14 or at the transmission input shaft 8 further reduce and be smaller than a third limit G3 If the sailing gear changes, it will be adjusted again, namely by changing from the sailing gear. S3B into sailing S2B , whereby for the new sailing gear S2B that as a clutch C trained, third switching element 11 opened, and that in the third positive forward gear V3 opened, as a brake A trained first switching element 9 will be closed.

[0042] Then, if the rotational speed at the output subsequently increases 14 becomes even smaller, namely smaller than a fourth limit. G4 , the sail course is adjusted once again, namely by the sail course S2B into sailing S2A , where the still closed part then acts as a coupling E trained fifth switching element 13 opened and the still open part, acting as a brake B trained second switching element 10 is closed, so that in sailing gear S2A then both as brakes A and B formed switching elements, namely the first switching element 9and the second switching element 10 , are closed, whereas all are couplings C , D and E formed switching elements, i.e. the third switching element 11 , the fourth switching element 12 and the fifth switching element 13 , all of which are open.

[0043] Depending on whether the drive unit is running 1 or deactivated drive unit 1 When sailing, the fourth limit value will be reached. G4 for changing from sailing S2B into sailing S2A chosen. Then, when sailing in sailing gear S2B the drive unit 1 Once shut down, a fourth limit value is applied. G4 chosen which has a defined offset greater than zero, so that the transition from sailing mode S2B into sailing S2A and thus the closing of the second one, as a coupling B trained switching element 10This occurs while the vehicle is still rolling. It is done while sailing. S2B with running drive unit 1 sailed, so the fourth limit is G4 a limit value was chosen that is based on the idle speed of the drive unit. 1 and a translation of the second positive forward gear V2 is dependent, in particular in such a way that when sailing with the engine running 1 the gear tracking from the sailing gear S2B into sailing S2A This occurs when a differential rotational speed is applied to the component acting as a brake. B trained second switching element 10 The difference in rotational speed at the point acting as a brake is zero. B trained second switching element 10 is zero when the synchronous speed of the second positive-locking forward gear is zero. V2 the current speed at the transmission input shaft 7 or the current speed of the drive unit 1 corresponds.

[0044] The above tracking of the sail settings from the entry sail setting S4B into sailing S3B , possibly subsequently into sailing gear S2B and, if necessary, subsequently into sailing gear S2A is possible with a high level of comfort.

[0045] Then, when entering sailing mode from the fourth forward gear with positive engagement V4 the first non-force-locking entry sailing gait S4A is inserted or is inserted, and subsequently the rotational speed at the output. 14 smaller than the first limit G1 will be from the sailing gear S4A into sailing S4B changed, specifically by using it as a brake. B trained second switching element 10 opened and for the switching matrix of the Fig. 3 that as a clutch E trained fifth switching element 13 or for which the switching matrix of Fig. 4 that as a clutch Dtrained fourth switching element 12 will be closed.

[0046] Then, when the first entry sail gear is engaged S4A the rotational speed at the output 14 or at the transmission input shaft 8 greater than a fifth limit G5 The sail's gait is also adjusted accordingly, namely by changing the sail's gait. S4A into sailing S5 is changed by the fact that the second switching element 10 , which acts as a brake B is executed, remains closed, whereas for the switching matrix of the Fig. 3 that as a clutch D trained fourth switching element 12 or for the switching matrix of the Fig. 4 that as a clutch E trained fifth switching element 13 opened and that as a clutch C trained third switching element 11 Each one is closed.

[0047] In the new sailing gear S5Therefore, this acts as a brake. B trained second switching element 10 , which in the third positive forward gear V3 , in fourth positive forward gear V4 and in the fifth positive forward gear V5 is closed, and that acts as a clutch C trained third switching element 11 , which in the third positive forward gear V3 and in the fifth positive forward gear V5 closed, but in fourth forward gear with positive engagement V4 is open, is closed.

[0048] The sailing gear corresponds to S5 according to the switching matrix of Fig. 3 a sailing trip S3A , which also leads to the third positive-locking forward gear V3 would fit.

[0049] Then, when the sailing gear S5 is inserted and subsequently the speed at the output 14 or at the transmission input shaft8 less than a sixth limit G6 The sailing gear will be adjusted again, namely by changing from the sailing gear S5 into sailing S3B . For this purpose, the forward gear is engaged in a positive-locking manner. V3 closed, as a brake B The designed switching element was opened. This is a coupling. E trained fifth switching element 13 However, it is closed, so that in the tracked sailing gear S3B the two as couplings C and E trained switching elements, in the third positive-locking forward gear V3 are closed, even in the tracked sailing gear S3B are closed, i.e., the third switching element 11 and the fifth switching element 13 .

[0050] The first limit G1 is greater than the second limit G2 , the second limit G2 is greater than the third limit G3and the third limit G3 is greater than the fourth limit G4 The fifth limit G5 is greater than the first limit G1 The sixth limit G6 is less than the fifth limit G5 , however greater than the second limit G2 .

[0051] With the method described above according to the invention, if starting from the fourth positive-locking forward gear V4 Once sailing mode is entered, it initially depends on the amount of downforce. 14 or the transmission output shaft 8 A suitable non-force-locking entry sailing gear for the applied speed S4A or S4B to be selected, whereby the following depends on the change in rotational speed at the output. 14 or the rotational speed at the transmission output shaft 8 The sail settings can be adjusted comfortably.

[0052] The invention further relates to a control unit for carrying out the method, i.e., for operating a motor vehicle with a drive unit. 1 , a gearbox 2 and a downswing 14 , whereby the gearbox 2 the four planetary gear sets 3 , 4 , 5 and 6 , the five switching elements 9 , 10 , 11 , 12 and 13 and the at least eight rotatable shafts 19 , 20 , 21 , 22 , 23 , 24 , 25 and 26 features which are linked together in the manner described above to transmit torque from the transmission input shaft 7 towards the transmission input shaft 8 to enable this, namely by providing at least eight positive-locking forward gears V1 until V8and at least one positive-locking reverse gear R.

[0053] The control unit, which is in particular an electronic transmission control unit, controls the switching elements of the transmission to carry out the method according to the invention. 2 for entering sailing mode and for the gear tracking described above. For this purpose, the control unit has data interfaces to exchange data with the assemblies involved in carrying out the method according to the invention, i.e., to control the switching elements of the transmission. 2 to control, depending on the output speed provided by a speed sensor. 14 , which can also be calculated.

[0054] Furthermore, the control unit has a processor for data processing and a memory for data storage. Program modules implemented in the control unit serve to carry out the method according to the invention. Reference symbol list 1 drive unit 2 automatic transmissions 3 first planetary gear set HO3 Ring gear first planetary gear set PL3 planetary gear first planetary gear set ST3 Bridge first planetary gear set SO3 Sun gear first planetary gear set 4 second planetary gear set HO4 ring gear second planetary gear set PL4 planetary gear, second planetary gear set ST4 Bridge second planetary gear set SO4 Sun gear, second planetary gear set 5 third planetary gear set HO5 ring gear third planetary gear set PL5 planetary gear third planetary gear set ST5 Bridge third planetary gear set SO5 sun gear third planetary gear set 6 fourth planetary gear set HO6 ring gear fourth planetary gear set PL6 planetary gear fourth planetary gear set ST6 Bridge fourth planetary gear set SO6 sun gear fourth planetary gear set 7 Gearbox input shaft 8 Gearbox output shaft 9 first switching element A brake 10 second switching element B brake 11 third switching element C coupling 12 fourth switching element D clutch 13 fifth switching element E clutch 14 Drive 15 converters 16 Turbine 17 Pump 18 Torque converter lock-up clutch 19 first wave 20 second wave 21 third wave 22 fourth wave 23 fifth wave 24 sixth wave 25 seventh wave 26 eighth wave 27 Gearbox housing 28 Entry Sailing Mode 29 Arrow 30 Arrow QUOTES INCLUDED IN THE DESCRIPTION

[0000] 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

[0000] DE 102005002337 A1 [0002, 0017, 0026] DE 102011005320 A1

[0003] DE 102010000857 A1

[0004] DE 102015220999 A1

[0005]

Claims

[1] Method for operating a motor vehicle with a drive unit (1), with a transmission (2) having four planetary gear sets (3, 4, 5, 6), five switching elements (9, 10, 11, 12, 13) and at least eight rotatable shafts (19, 20, 21, 22, 23, 24, 25, 26), and with an output (14), wherein the transmission (2) is designed as an automatic or automated transmission, is connected between the drive unit (1) and the output (14) and provides at least eight frictional forward gears and at least one frictional reverse gear by selectively closing and opening the switching elements (9, 10, 11, 12, 13), and wherein three of the five switching elements are designed as clutches (C, D, E) and two of the five switching elements are designed as brakes (A, B), wherein in each engaged, friction-fit gear of the transmission (2) a first number of the switching elements (9, 10, 11, 12, 13) of the transmission (2) are closed and a second number of the switching elements (9, 10, 11, 12, 13) of the transmission (2) are open, where, depending on at least one operating condition of the motor vehicle, a sailing mode is entered, wherein, to enter the sailing mode of the motor vehicle starting from a positive-locking forward gear, a switching element of the transmission (2) is actuated to open, so that in a non-positive-locking sailing gear one switching element is less closed and thus one more switching element is open than in a positive-locking gear, wherein, in the sailing mode of the motor vehicle, the respective closed and open switching elements of the transmission (2) are changed depending on at least one operating condition of the motor vehicle to maintain the sailing gear, characterized by, that then, when starting from a fourth positive-locking forward gear (V4), in which a switching element (10) designed as a brake (B) and two switching elements (12, 13) designed as clutches (D, E) are closed, when the sailing mode is entered, depending on a speed at the output (14) or depending on a speed at a transmission output shaft (8), a non-positive-locking entry sailing gear (S4A, S4B) is engaged such that then, when the rotational speed at the output (14) or at the transmission output shaft (8) is greater than a first limit value (G1), a first non-friction-engaged entry coasting gear (S4A) is engaged such that one of the two switching elements (13) designed as clutches (E or D) is opened, so that in the non-friction-engaged entry coasting gear (S4A) the switching element (10) designed as a brake (B) and one of the two switching elements (12) designed as clutches (D or E) are closed, then when the rotational speed at the output (14) or at the transmission output shaft (8) is less than the first limit value (G1), a second non-friction-engaging entry coasting gear (S4B) is engaged in such a way that the switching element (10) designed as a brake (B) is opened, so that in the non-friction-engaging entry coasting gear (S4B) the two switching elements (12, 13) designed as clutches (D, E) are closed. [2] Method according to claim 1, characterized by, that when the second non-force-locking entry sailing gear (S4B) is engaged and the speed at the output (14) or at the transmission output shaft (8) becomes less than a second limit value (G2), the sailing gear is adjusted, namely in such a way that for the new sailing gear (S3B) one of the two closed switching elements (12) designed as clutches (D) is opened and another switching element (11) designed as a clutch (C) is closed, so that in the new sailing gear (S3B) the switching elements (11, 13) designed as clutches (C, E) which were closed in the third force-locking forward gear (V3) are closed. [3] Method according to claim 2, characterized by, that when the rotational speed at the output (14) or at the transmission output shaft (8) becomes less than a third limit value (G3), the sailing gear is readjusted, namely in such a way that for the new sailing gear (S2B) one of the two closed switching elements (11) designed as clutches (C) is opened and the switching element (9) designed as a brake (A) which was open in the third positive forward gear (V3) is closed. [4] Method according to claim 3, characterized by, that when the rotational speed at the output (14) becomes less than a fourth limit value (G4), the sailing gear is readjusted, namely in such a way that for the new sailing gear (S2A) the still closed switching element (13) designed as a clutch (E) is opened and the still open switching element (10) designed as a brake (B) is closed, so that then both switching elements (9, 10) designed as brakes (A, B) are closed and all switching elements (11, 12, 13) designed as clutches (C, D, E) are open. [5] Method according to any one of claims 1 to 4, characterized by, that when the first non-power-engaged entry sailing gear (S4A) is engaged and the rotational speed at the output (14) or at the transmission output shaft (8) exceeds a fifth limit value (G5), the sailing gear is adjusted, namely in such a way that for the new sailing gear (S5) the closed switching element (12) designed as a clutch (D or E) is opened and another switching element (11) designed as a clutch (C) is closed, so that in the new sailing gear (S5) the switching element (10) designed as a brake (B), which is closed in the third, fourth and fifth power-engaged forward gear (V3, V4, V5), and the switching element (11) designed as a clutch (C), which is closed in the third and fifth power-engaged forward gear (V3, V5) but open in the fourth power-engaged forward gear (V4), is closed. [6] Method according to claim 5, characterized by, that if the rotational speed at the output (14) or at the transmission output shaft (8) subsequently becomes less than a sixth limit value (S6), the sailing gear is readjusted, namely in such a way that the switching element (10) designed as a brake (B), which is closed in the positive-locking third forward gear (V3), is opened and the other switching element (10) designed as a clutch (E) and which is closed in the positive-locking third forward gear (V3), is closed, so that in the readjusted sailing gear (S3B) the two switching elements (11, 13) designed as clutches (C, E), which are closed in the third positive-locking forward gear (V3), are closed. [7] Method according to any one of claims 2 to 6, characterized by , that the second limit (G2) is smaller than the first limit (G1), the third limit (G3) is smaller than the second limit (G2) and the fourth limit (G4) is smaller than the first limit (G1). [8] Method according to any one of claims 5 to 7, characterized by , that the fifth limit (G5) is greater than the first limit (G1) and the sixth limit (G6) is less than the fifth limit (G5) but greater than the second limit (G2). [9] Control unit for operating a motor vehicle comprising a drive unit (1), a transmission (2) having four planetary gear sets (3, 4, 5, 6), five switching elements (9, 10, 11, 12, 13) and at least eight rotatable shafts (19, 20, 21, 22, 23, 24, 25, 26), and an output (14), wherein the transmission (2) is designed as an automatic or automated transmission, is connected between the drive unit (1) and the output (14) and provides at least eight positive forward gears and at least one positive reverse gear by selectively closing and opening the switching elements (9, 10, 11, 12, 13), and wherein three of the five switching elements are designed as clutches (C, D, E) and two of the five switching elements are designed as brakes (A, B), wherein the control unit in each engaged, positive-locking gear of the transmission (2) controls a first number of switching elements of the transmission (2) to close and a second number of switching elements of the transmission (2) to open, the control unit controls the transmission (2) to transfer it into a sailing mode, depending on at least one operating condition of the motor vehicle, The control unit, starting from a positive-locking forward gear, activates a switching element of the transmission (2) to open in order to enter sailing mode, so that in a non-positive-locking sailing gear one less switching element is closed and thus one more switching element is open than in a positive-locking gear. the control unit in the sailing mode of the motor vehicle changes the respective closed and open switching elements of the transmission (2) depending on at least one operating condition of the motor vehicle in order to maintain the sailing gear, characterized by , that then, when the control unit, starting from a fourth positive-locking forward gear (V4) in which a switching element (10) designed as a brake (B) and two switching elements (12, 13) designed as clutches (D, E) are closed, executes the entry into the sailing mode on the control side, the switching elements are controlled depending on a speed at the output (14) or depending on a speed at a transmission output shaft (8) to engage a non-positive-locking entry sailing gear (S4A, S4B) in such a way that then, when the rotational speed at the output (14) or at the transmission output shaft (8) is greater than a first limit value (G1), a first non-friction-engaged entry coasting gear (S4A) is engaged such that one of the two switching elements (13) designed as clutches (E or D) is opened, so that in the non-friction-engaged entry coasting gear (S4A) the switching element (10) designed as a brake (B) and one of the two switching elements (12) designed as clutches (D or E) are closed, then when the rotational speed at the output (14) or at the transmission output shaft (8) is less than the first limit value (G1), a second non-friction-engaging entry coasting gear (S4B) is engaged in such a way that the switching element (10) designed as a brake (B) is opened, so that in the non-friction-engaging entry coasting gear (S4B) the two switching elements (12, 13) designed as clutches (D, E) are closed. [10] Control unit according to claim 9, characterized bythat the same executes the method according to one of claims 1 to 8 on the control side.

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