DE102019218527A1 - Method and control device for operating a pneumatic switching system of a transmission - Google Patents

Abstract

Method for operating a pneumatic shifting system of a transmission having at least one transmission group (SGr, MGr, GGr), the shifting system having pressure-medium-actuated assemblies such as shift cylinders (10, 11, 12) of the respective transmission group and a transmission brake (TBr), with each pressure-medium-actuated assembly at least one switching valve (23) interacts, the switching system having a pressure regulator chamber (16) from which the pressure medium-actuated assemblies are supplied with pressure medium depending on the switching position of the switching valves (23), the switching system having a reservoir (24) for pressure medium, from which the pressure regulator space (16) is supplied with pressure medium, the switching system having switching valves (27) connected between the reservoir (24) and the pressure regulator space (16) which are operated by a pressure regulator (29) to regulate the pressure in the pressure regulator space (16 ) can be controlled. When at least one of the pressure-actuated switching cylinders (10, 11, 12) is supplied with pressure medium from the pressure regulator space (16) to carry out a shift, the pressure regulator (29) controls the switches connected between the reservoir (24) and the pressure regulator space (16) Switching valves (27) based on a pressure-medium mass flow-based pilot control component in order to provide a switching pressure required for controlling the at least one switching cylinder in the pressure regulator space (16).

Description

The invention relates to a method and a control device for operating a pneumatic shift system of a transmission.

From the DE 10 2011 088 832 A1 a pneumatic shift system of a transmission with pressure-medium-actuated shift cylinders is known. At least one switching valve interacts with each switching cylinder. A pressure regulator space of the switching system, from which the switching cylinders can be supplied with pressure medium depending on the switching position of the switching valves, can be supplied with pressure medium from a storage container. The pressure actuator space is also referred to as the transmission actuator space. Switching valves, which can be used to regulate the pressure in the pressure regulator space, are connected between the reservoir and the pressure regulator space of the gearshift system. These switching valves connected between the storage container and the pressure regulator space are also referred to as main shut-off valves. The pressure in the pressure regulator area can be regulated by activating the main shut-off valves. To this end, the DE 10 2011 088 832 B4 propose to determine a pressure medium requirement in that a volume newly created at the respective point in time of the opening of the switching valves is used and this newly created volume is considered relative to an already existing storage volume. This corresponds to a volume-based control or regulation of the switching pressure in the pressure regulator space of the pneumatic switching system. Such a volume-based control or regulation of the pressure in the pressure regulator space is not precise and robust enough. Pressure change dynamics and position change dynamics cannot be taken into account. This ultimately results in poor shift quality.

From the DE10 2006 040 476 A Another pneumatic switching system of a transmission is known.

There is a need to improve the shift quality in a transmission with a pneumatic shift system.

The invention is based on the object of creating a novel method and a control device for operating a pneumatic shift system of a transmission.

This object is achieved by a method for operating a pneumatic shift system of a transmission according to patent claim 1. According to the invention, if at least one of the pressure-medium-actuated shift cylinders is supplied with pressure medium from the pressure regulator chamber to carry out a shift in the transmission, the pressure regulator controls the switching valves connected between the reservoir and the pressure regulator chamber on the basis of a pressure-medium mass flow-based pilot control component in order to provide one in the pressure regulator chamber to control the at least to provide a switching cylinder requested switching pressure.

The invention does not use a volume-based control or regulation of the switching pressure in the pressure actuator space, but rather a pressure-medium mass flow-based pilot control component via which a switching pressure required for the shift to be carried out in the pressure actuator space can be provided precisely and quickly. The disadvantages of volume-based control or regulation can be avoided. The switching pressure in the pressure actuator space can be provided precisely and robustly. Pressure change dynamics and position change dynamics can be taken into account.

According to an advantageous development of the invention, the pressure-medium mass flow-based pilot control component of the pressure regulator is calculated in a model-based manner, with a pressure-medium mass flow required for the circuit being calculated in the model-based calculation of the pilot control component of the pressure regulator. When calculating the pressure medium mass flow required for the shift, pressure change dynamics and position change dynamics can be taken into account. The pressure medium mass flow can be calculated in such a way that ultimately the requested switching pressure can be provided precisely and robustly.

According to an advantageous development of the invention, the pressure medium mass flow required for the switching is divided between two switching valves connected between the reservoir and the pressure regulator space that, when the same is smaller than a pressure medium mass flow that can be provided by a single one of the two switching valves, the required pressure medium mass flow is achieved by controlling a single switching valve is provided, and that otherwise the required pressure medium mass flow is divided between the two switching valves by appropriate control of the same. This is preferred in order to use the switching valves uniformly in view of wear and tear of the same.

According to an advantageous development of the invention, for each switching valve controlled to provide the required pressure medium mass flow, a control frequency is determined depending on the partial mass flow of the pressure medium mass flow to be provided by the respective switching valve and depending on a pressure ratio between the target pressure of the circuit and a system pressure in the reservoir, preferably as a function of the map. The map-dependent determination of the control frequencies for the switching valves depending on the pressure medium mass flow to be provided and depending on the pressure ratio between the target pressure of the circuit and the system pressure in the reservoir is simple and accurate.

The control device according to the invention is defined in claim 9.

• 1 ein Schema eines Getriebes und eines Schaltsystems des Getriebes zur Verdeutlichung der Erfindung;
• 2 ein Blockschaltbild zur weiteren Verdeutlichung der Erfindung.

Preferred developments emerge from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being restricted thereto. It shows:

• 1 a diagram of a transmission and a switching system of the transmission to illustrate the invention;
• 2 a block diagram to further illustrate the invention.

1 shows a highly schematic block diagram of a pneumatic shifting system of a transmission of a motor vehicle designed as a group transmission.

So shows 1 Hydraulic cylinder 10 , 11 and 12th , namely a fluid cylinder 11 for a so-called main group MGr of the group transmission, a pressure cylinder 10 for a so-called upstream group SGr of the group transmission and a pressure cylinder 12th for a so-called downstream group GGr of the group transmission. The upstream group SGr is also referred to as a splitter and the downstream group GGr is also referred to as a range group.

Each pressure cylinder 10 , 11 , 12th has a piston 13th , 14th or. 15th , the one in the respective pressure cylinder 10 , 11 , 12th is displaceable in order to carry out shifts in the respective group of the group transmission. The respective pressure cylinder 10 , 11 , 12th can be based on a pressure regulator room 16 of the switching system of the transmission are supplied with compressed air, for this purpose from the pressure regulator space 16 Compressed air lines 17th , 18th or. 19th , 20th or. 21 , 22nd in the direction of the respective pressure cylinder 10 , 11 , 12th to lead. The pressure regulator room 16 is also referred to as the gearbox actuator room. In the exemplary embodiment lead to each pressure cylinder 10 , 11 , 12th two compressed air lines each 17th , 18th or. 19th , 20th or. 21 , 22nd to supply pressure chambers of the respective pressure medium cylinder with compressed air. In each of the compressed air lines 17th to 22nd is one valve each 23 integrated.

The pressure regulator room 16 can starting from a storage container 24 , which is also referred to as a pressure vessel, can be supplied with compressed air. From the storage container 24 lead compressed air lines 25th , 26th in the direction of the pressure regulator room 16 to depending on the position of valves 27 that are in these compressed air lines 25th , 26th are integrated, compressed air starting from the storage tank 24 in the pressure regulator room 16 to promote. The valves 27 are also referred to as main shut-off valves.

In the pressure regulator room 16 is a pressure sensor 28 installed, with the help of which the switching pressure in the pressure actuator area 16 can be recorded by measurement. One using the pressure sensor 28 Actual switching pressure recorded by measurement in the pressure regulator area 16 can be compared with a desired target switching pressure in order to control the valves depending on a deviation between the actual switching pressure and the target switching pressure 27 for regulating the switching pressure in the pressure regulator room 16 head for. A pressure regulator is used for this 29 .

According to 1 the pneumatic shift system shown there also includes a transmission brake TBr. The transmission brake TBr is also a pneumatic pressure medium consumer, which starts from the pressure actuator area 16 Pressure medium can be made available, namely again via a switching valve 23 .

If a shift is now to be carried out in the transmission, namely with the participation of at least one of the subtransmissions, i.e. with the participation of the main group MGr and / or the upstream group SGr and / or the downstream group GGr, this must be done in the pressure regulator room 16 a defined switching pressure or target switching pressure can be provided, including the pressure regulator space 16 depending on which pressure medium consumer is involved in the execution, a corresponding amount of pressure medium starting from the reservoir 24 must be supplied.

The present invention now relates to a method, with the aid of which the setpoint switching pressure in the pressure regulator chamber that is required when performing a shift in the transmission 16 can be made available quickly and accurately, even if there is a sudden high consumption of pressure medium during a shift.

With the invention it is proposed that, when performing a shift in the transmission, at least one of the pressure-medium-actuated shift cylinders 10 , 11 , 12th from main group MGr, upstream group SGr, downstream group GGr starting from the pressure regulator room 16 is supplied with pressure medium, the pressure regulator 29 those between the reservoir 24 and the pressure regulator room 16 switched switching valves 27 based on a pressure fluid mass flow-based pilot control component controls to in the pressure actuator space 16 to quickly and accurately provide the switching pressure required to control the at least one switching cylinder.

This pressure medium mass flow-based pilot control component of the pressure regulator 29 calculates a pressure medium mass flow required for switching, which is used to set the target switching pressure in the pressure actuator space 16 the same starting from the storage container 24 must be supplied, model-based.

$$V_1=V_0+V_{\mathrm{0,}j}+V_i\left(s_i\right),i=\left\{SGr,MGr,GGr\right\},j=\left\{SGr,MGr,GGr,TBr\right\}$$

$${\dot{V}}_1={\dot{s}}_i\frac{dV}{d{s}_i}\left(s_i\right),i=\left\{SGr,MGr,GGr\right\},$$

wobei

ṁ1d

der für die Schaltung benötigte Druckmittelmassenstrom vom Vorratsbehälter 24 in den Druckstellerraum 16 ist,

R

eine pneumatische Gaskonstante der Luft ist,

T

eine Lufttemperatur im Getriebe ist,

ṗ1

eine Druckänderungsrate im Druckstellerraum 16 während der Schaltung ist,

V1

ein aktives Volumen während der Schaltung ist,

p1d

der Soll-Druck der Schaltung ist,

die aktive Volumenänderungsrate der Schaltung ist,

V0

das Totvolumen des Druckstellerraums 16 ist,

V0,j

das Totvolumen des jeweiligen in der Schaltung aktiven Schaltzylinders 10, 11, 12 der jeweiligen Getriebegruppe SGr, MGr, GGr und der Getriebebremse TBr ist,

Vi

das aktive Volumen des jeweiligen in der Schaltung aktiven Schaltzylinders 10, 11, 12 der jeweiligen Getriebegruppe SGr, MGr, GGr ist,

si

die gemessene Kolbenposition des jeweiligen in der Schaltung aktiven Schaltzylinders 10, 11, 12 der jeweiligen Getriebegruppe SGr, MGr, GGr ist,

ṡi

die Kolbengeschwindigkeit des jeweiligen in der Schaltung aktiven Schaltzylinders 10, 11, 12 der jeweiligen Getriebegruppe SGr, MGr, GGr ist.

The pressure medium mass flow required for the shift is preferably calculated based on the model based on the following equations: $${\dot{m}}_{1d}=\frac{1}{\mathrm{R.}T}\left({\dot{p}}_1{V}_1+p_{1d}{\dot{V}}_1\right),$$

$$V_1={\mathrm{<figure-callout\; id="0"\; label="V"\; filenames="DE102019218527A1\_0010.png"\; state="\{\{state\}\}">V</figure-callout>}}_0+{\mathrm{<figure-callout\; id="0"\; label="V"\; filenames="DE102019218527A1\_0010.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{0,}j}+V_i\left(s_i\right),i=\left\{\mathrm{S.}Gr,\mathrm{M.}Gr,GGr\right\},j=\left\{\mathrm{S.}Gr,\mathrm{M.}Gr,GGr,T\mathrm{B.}r\right\}$$

$${\dot{V}}_1={\dot{s}}_i\frac{dV}{d{s}_i}\left(s_i\right),i=\left\{\mathrm{S.}Gr,\mathrm{M.}Gr,GGr\right\},$$

in which

ṁ1d

the pressure medium mass flow required for the circuit from the reservoir 24 in the pressure regulator room 16 is

R.

is a pneumatic gas constant of air,

T

there is an air temperature in the gearbox,

ṗ1

a rate of pressure change in the pressure regulator room 16 while the circuit is

V1

is an active volume during the shift,

p1d

is the target pressure of the circuit,

is the active volume change rate of the circuit,

V0

the dead volume of the pressure regulator space 16 is

V0, j

the dead volume of the respective shift cylinder active in the shift 10 , 11 , 12th the respective gear group is SGr, MGr, GGr and the gear brake TBr,

Vi

the active volume of the respective shift cylinder active in the circuit 10 , 11 , 12th the respective gear group is SGr, MGr, GGr,

si

is the measured piston position of the respective shift cylinder 10, 11, 12 of the respective transmission group SGr, MGr, GGr that is active in the shift,

ṡi

is the piston speed of the respective shift cylinder 10, 11, 12 of the respective gear group SGr, MGr, GGr that is active in the shift.

With the above dead volume of the respective shift cylinder 10 , 11 , 12th and the transmission brake TBr is the respective dead volume including the corresponding supply lines. Only the dead volume of pressure medium consumers that are active when the switching is carried out is taken into account. If only the main group MGr is active during a shift to be carried out, then only the dead volume of this main group MGr is also active relevant. The same applies to the above active volume of the respective shift cylinder 10 , 11 , 12th . If only the upstream group SGr is active when a shift is to be carried out, then only the active volume of the shift cylinder is also active 10 of the control group SGr relevant.

The above piston position of the respective shift cylinder active in the shift 10 , 11 , 12th is measured, in particular with the aid of one of the respective shift cylinders 10 , 11 , 12th assigned position sensor. The piston speed of the respective shift cylinder active in the circuit can be determined from the measured piston position 10 , 11 , 12th can be calculated, namely by a derivative of the measured piston position with respect to time. The rate of pressure change in the pressure regulator space is also calculated from a measured variable, specifically by deriving the pressure over time with the aid of the pressure sensor 28 measured pressure in the pressure regulator room 16 .

From the above equations for the model-based calculation of the pressure medium mass flow required for the shift, it follows that the pressure regulator 29 on the basis of defined input variables, which in 1 in dashed lines and in 2 are shown in solid lines, in a calculation component 30th of the pressure regulator 29 the pressure medium mass flow required for the circuit is calculated. With the input variables 31 of the block 30th it is in particular the target pressure of the circuit or the target switching pressure, the measured piston position of the respective shift cylinder, the piston speed of the respective shift cylinder calculated depending on the measured piston position and the pressure change rate calculated depending on the measured pressure in the pressure regulator chamber Pressure regulator room. Depending on these input variables 31 the block calculates 30th as an output variable 32 the pressure medium mass flow required for the circuit.

This pressure medium mass flow required for the circuit becomes a block 33 of the pressure regulator 29 provided, which is a logic component and the pressure medium mass flow required for the circuit to the two between the reservoir 24 and the pressure regulator room 16 switched switching valves 27 divides.

This division is preferably carried out in such a way that when the model-based calculated pressure medium mass flow required for the shift is less than one of a single one of the two shift valves 27 The pressure medium mass flow that can be provided is the pressure medium mass flow required by actuating a single one of the two switching valves 27 provided.

If, on the other hand, the model-based calculated pressure medium mass flow is greater than the pressure medium mass flow that of a single one of the two switching valves 27 can be provided, the required pressure medium mass flow, which was calculated based on the model, is applied to the two switching valves 27 divided, preferably evenly, so that the two switching valves connected in parallel 27 then both each provide half of the required pressure medium mass flow.

The block 33 or the logic component is accordingly for each of the two switching valves 27 a partial mass flow 34 , 35 of the required pressure medium mass flow, the respective partial mass flow of one of the switching valves 27 Is zero if the total pressure medium mass flow required 32 from a single switching valve 27 can be provided.

For each to provide the required pressure medium mass flow 32 controlled switching valve 27 is used as the output variable of the pressure regulator 29 a control frequency 35 , 37 for the respective switching valve 27 determined, the respective control frequency 35 , 37 depending on by the respective switching valve 27 partial mass flow to be provided 34 , 36 of the pressure medium mass flow 32 and depending on a pressure ratio between the setpoint pressure of the circuit and the system pressure in the reservoir 24 is determined. This is done according to 2 map-dependent.

With the invention, the switching pressure in the pressure regulator chamber can accordingly be achieved when a shift is carried out in a transmission with a pneumatic shift system 16 are maintained, namely by providing a required pressure medium mass flow from the reservoir 24 by activating the switching valves 27 starting from the pressure regulator 29 . The pressure regulator 29 determines the pressure medium mass flow required for the shift based on a model, divides this determined pressure medium mass flow into the switching valves depending on its size 27 and preferably determined as a function of the map for the respective switching valve 27 the control frequency with which the same is controlled to provide the respective pressure medium mass flow. This allows the switching pressure to be maintained accurately and robustly in the pressure regulator room 16 with circuit design with high shift quality. Both a change in the pressure dynamics and a change in the position dynamics are taken into account.

The invention further relates to a control unit of a transmission which is set up to carry out the method or methods described above on the control side. The control device comprises means for carrying out the method according to the invention, namely hardware-based means and software-based means. The hardware means include data interfaces in order to exchange data on the control side with the assemblies involved in the execution of the method according to the invention. Furthermore, the control device comprises, as hardware-side means, a processor for data processing and a memory for data storage. The software-based means include program modules for carrying out the method according to the invention.

List of reference symbols

10

Hydraulic cylinder

11

Hydraulic cylinder

12th

Hydraulic cylinder

13th

piston

14th

piston

15th

piston

16

Pressure regulator room

17th

Pressure medium line

18th

Pressure medium line

19th

Pressure medium line

20th

Pressure medium line

21

Pressure medium line

22nd

Pressure medium line

23

Valve

24

Storage container

25th

Pressure medium line

26th

Pressure medium line

27

Valve

28

Pressure sensor

29

Pressure regulator

30th

Calculation component

31

Input variable

32

Pressure medium mass flow

33

Logic component

34

Partial mass flow

35

Control frequency

36

Partial mass flow

37

Control frequency

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011088832 A1 [0002]
• DE 102011088832 B4 [0002]
• DE 102006040476 A [0003]

Claims (10)

Method for operating a pneumatic shifting system of a transmission having at least one transmission group (SGr, MGr, GGr), the pneumatic shifting system being pressurized assemblies such as shift cylinders (10, 11, 12) of the respective transmission group (SGr, MGr, GGr) and a transmission brake (TBr ), with at least one switching valve (23) interacting with each pressure-medium-operated assembly, the pneumatic switching system having a pressure-setting chamber (16) from which the pressure-fluid-operated assemblies are supplied with pressure medium depending on the switching position of the switching valves (23), the pneumatic Switching system has a reservoir (24) for pressure medium, from which the pressure regulator space (16) is supplied with pressure medium, the pneumatic switching system having switching valves (27) connected between the reservoir (24) and the pressure regulator space (16), which are controlled by a pressure regulator (29) to regulate the pressure in the pressure valve ellerraum (16) are controlled, characterized in that when at least one of the pressure-actuated shift cylinders (10, 11, 12) is supplied with pressure medium from the pressure actuator space (16) to carry out a shift in the transmission, the pressure regulator (29) between controls the storage container (24) and the pressure regulator space (16) switched switching valves (27) on the basis of a pressure medium mass flow-based pilot control component in order to provide a switching pressure required for the control of the at least one switching cylinder (10, 11, 12) in the pressure regulator space (16). Procedure according to Claim 1 , characterized in that the pressure-medium mass flow-based pilot control component of the pressure regulator (29) is calculated based on a model. Procedure according to Claim 2 , characterized in that in the model-based calculation of the pilot control component of the pressure regulator (29), a pressure medium mass flow required for the shift is calculated. Procedure according to Claim 3 , characterized in that the pressure medium mass flow required for the shift is calculated as follows: $${\dot{m}}_{1d}=\frac{1}{\mathrm{R.}T}\left({\dot{p}}_1{V}_1+p_{1d}{\dot{V}}_1\right),$$

$$V_1=V_0+V_{\mathrm{0,}j}+V_i\left(s_i\right),i=\left\{\mathrm{S.}Gr,\mathrm{M.}Gr,GGr\right\},j=\left\{\mathrm{S.}Gr,\mathrm{M.}Gr,GGr,T\mathrm{B.}r\right\}$$

$${\dot{V}}_1={\dot{s}}_i\frac{dV}{d{s}_i}\left(s_i\right),i=\left\{\mathrm{S.}Gr,\mathrm{M.}Gr,GGr\right\},$$

where ṁ _{1d is} the pressure medium mass flow required for the shift from the reservoir (24) into the pressure regulator space (16), R is a pneumatic gas constant of the air, T is an air temperature in the transmission, ṗ _{1 is} a rate of pressure change in the pressure regulator space (16) during the shift , V _{1 is} an active volume during the shift, p _{1d is} the target pressure of the shift,

is the active volume change rate of the shift, V _{0 is} the dead volume of the pressure _{regulator space (16), V 0, j is} the dead volume of the respective shift cylinder (10, 11, 12) active in the shift of the respective transmission group (SGr, MGr, GGr) and the Transmission brake (TBr), V _{i is} the active volume of the respective shift cylinder (10, 11, 12) of the respective gear group (SGr, MGr, GGr) _{active in the shift, s i is} the measured piston position of the respective shift cylinder active in the shift ( 10, 11, 12) of the respective gear group (SGr, MGr, GGr), s _{i is} the piston speed of the respective shift cylinder (10, 11, 12) of the respective gear group (SGr, MGr, GGr) active in the shift. Method according to one of the Claims 1 to 4th , characterized in that the pressure medium mass flow required for the switching is divided between two switching valves (27) connected between the reservoir (24) and the pressure regulator space (16), that if the same is less than a pressure medium mass flow which can be provided by a single one of the two switching valves is, the required pressure medium mass flow is provided by controlling a single switching valve, and that otherwise the required pressure medium mass flow is divided between the two switching valves (27) by corresponding control of the same. Procedure according to Claim 5 , characterized in that when the required pressure medium mass flow is greater than a pressure medium mass flow that can be provided by a single one of the two switching valves, the required pressure medium mass flow is evenly divided between the two switching valves (27). Method according to one of the Claims 1 to 6th , characterized in that for each switching valve (27) controlled to provide the required pressure medium mass flow, a control frequency is dependent on the partial mass flow of the pressure medium mass flow to be provided by the respective switching valve (27) and depending on a pressure ratio between the target pressure of the circuit and a system pressure in the reservoir ( 24) is determined. Procedure according to Claim 7 , characterized in that the control frequency is determined as a function of the map. Control unit of a transmission for operating a pneumatic switching system of the transmission, the control unit activating switching valves (27) connected between a storage container (24) and a pressure regulator chamber (16) of the switching system via a pressure regulator (29) to regulate the pressure in the pressure regulator chamber (16), characterized in that the control unit is supplied with pressure medium from the pressure regulator chamber (16) when at least one pressure-medium-actuated shift cylinder (10, 11, 12) of the shifting system is supplied with pressure medium to carry out a shift in the transmission, the pressure regulator (29) between the reservoir (24 ) and controls the pressure regulator space (16) switched switching valves (27) on the basis of a pressure medium mass flow-based pilot control component in order to provide a switching pressure required for the control of the at least one switching cylinder (10, 11, 12) in the pressure regulator space (16) Control unit after Claim 9 , characterized in that the same is set up the method according to one of the Claims 1 to 8th to be carried out on the control side.

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