KR102472609B1 - Method for reducing, if required, a drag torque of a friction clutch - Google Patents

Abstract

The present invention relates to a method for on-demand reduction of the drag torque of an automotive friction clutch, in particular wet, automatically operable between open and closed positions during a gear change, in response to a gear change request (302). , first the drag torque state 304 is determined, and then it is determined whether the requested gear change can be executed without a reduction in drag torque or whether a reduction in drag torque is required.

Description

Method for reducing the drag torque of a friction clutch as needed {METHOD FOR REDUCING, IF REQUIRED, A DRAG TORQUE OF A FRICTION CLUTCH}

The present invention relates to a method for on-demand reduction of the drag torque of a motor vehicle friction clutch, in particular wet, automatically operable between an open and closed position during a gear change.

DE 10 2013 205 107 A1 discloses a method for controlling a wet motor vehicle friction clutch which is automatically operable between open and closed positions, the friction clutch comprising a pressure plate, axially displaceable relative to the pressure plate. a contact plate and a clutch disk clampable between the pressure plate and the contact plate, wherein the friction clutch is controlled based on the clutch characteristic curve, the clutch drag torque characteristic curve is determined, and the modulated clutch characteristic curve is obtained; The clutch drag torque characteristic curve is superimposed on the clutch characteristic curve.

The object of the present invention is to improve the method mentioned at the outset. In particular, a sufficient reduction in drag torque should be possible. In particular, it should be possible to rapidly reduce the drag torque. In particular, there should be no need for active energy supply for reduction of drag torque. In particular, opening of the friction clutch should be prevented if possible. In particular, the shifting time and shifting force should be reduced or maintained constant regardless of the temperature effect when the shift stage is changed. In particular, driving comfort should be increased.

The above problem is solved by a method for the demand reduction of the drag torque of a motor vehicle friction clutch, in particular wet, which is automatically operable between open and closed positions during a gear change, in response to a gear change request: First, the drag torque state is determined and then it is determined whether the requested gear change can be executed without a reduction in drag torque or whether a reduction in drag torque is required.

A friction clutch may be part of a friction clutch device. The friction clutch may form a single clutch. The friction clutch may form a dual clutch with an additional friction clutch. The friction clutch may be a single disc clutch. The friction clutch may be a multi-disc clutch. The friction clutch may include a pressure plate, a contact plate displaceable in an axial direction relative to the pressure plate, and a clutch disk clampable for frictionally coupled power transmission between the pressure plate and the contact plate. A friction clutch can include an input component and an output component. The pressure plate and the contact plate may belong to the input part. The clutch disc may belong to the output part.

A wet friction clutch may be a friction clutch that is pressurized by a fluid flow. The fluid flow can in particular be used for cooling the friction clutch. The fluid may be oil. The fluid may be transmission oil. A drag torque can occur in non-closed friction clutches. The drag torque can be induced through the transfer of power caused by the fluid. The drag torque may depend on the specified properties, viscosity and/or temperature of the fluid. The drag torque may depend on the type of cooling circuit, in particular the location and structure of the cooling oil pump. The drag torque may depend on the clearance of the clutch disc from the pressure plate and/or contact plate.

A friction clutch may be used for arrangement within a drive train of a vehicle. The drive train may include an internal combustion engine. The drive train may include a transmission. The transmission may be a manual transmission. The transmission may be manual and/or automatically variable. A friction clutch may be arranged between the internal combustion engine and the transmission in the drive train. The input part of the friction clutch may be in drive connection with the output shaft of the internal combustion engine. The output part of the friction clutch may be in driving connection with the input shaft of the transmission. The terms “input component” and “output component” relate to the direction of output flow from an internal combustion engine.

The friction clutch provides an increased power transmission from a fully open operating position in which no power transfer is actually carried out between the input and output components to a fully closed operating position in which a virtually complete power transfer is carried out between the input and output components. Depending on this operation, it may be possible, and the transmission of power between the input part and the output part is carried out in a frictional manner. Conversely, from the fully closed operating position, where there is actually a complete power transfer between the input and output parts, to the fully open operating position, where no output transfer is actually carried out between the input and output parts, the power transfer is reduced. may be possible depending on

The friction clutch device may include an actuator device. The friction clutch may be actuated by an actuator device. The actuator device may be a hydrostatic actuator device. An actuator device may be used for semi-hydraulic control of the friction clutch. The actuator device may include a hydraulic section. The actuator device may include a slave cylinder. The actuator device may include a master cylinder. A master cylinder may be used to pressurize the friction clutch. The hydraulic section is used to transfer power between the master cylinder and the slave cylinder. The actuator device may include an electric motor drive. This driving unit can be used for pressurizing the slave cylinder. The actuator device may include a transmission.

The friction clutch device may include a control device. The control device may be a local control device. The control device may be a higher control device. The control device can be used for open-loop control and closed-loop control of a friction clutch device, a friction clutch device, an actuator device and/or an electric motor drive of the actuator device. The method according to the invention can be executed by a control device. The control device may include an electrical controller. The control device may include a memory device. The memory device may include non-volatile electronic memory, the stored information of which may be electrically erased or overwritten. The control device may include EEPROM. The control device may include an arithmetic device.

The friction clutch device may include a sensor for determining the setting position of the friction clutch device. The sensor may be a position sensor. Such a sensor can be used for determining the setting position of the friction clutch. Such a sensor can be used for determining the set position of the actuator device. The friction clutch device may include a sensor for determining the transmitted torque. This sensor may be a torque sensor. The friction clutch device may include a sensor for determining the slip of the friction clutch. Slip may be the rotational speed difference between the input and output parts of the friction clutch. The friction clutch device may include a sensor for determining fluid flow. The friction clutch device may in particular include a sensor for determining the temperature of the fluid.

The drag torque state is determined by, for example, the measured drag torque, the clutch temperature, the coolant temperature, the energy input into the friction clutch since the last shutdown, the number of clutch operations since the last shutdown, and/or the simulated It can be determined by considering the operating displacement caused by wear.

To determine the drag torque state, the contact point can be determined on the basis of the measured or calculated clutch characteristic curve in the new state of the friction clutch. A clutch characteristic curve is stored or may be stored in a memory device. The clutch characteristic curve can represent the torque transmitted by the friction clutch, depending on the setting position of the friction clutch device, the friction clutch or the actuator device. The clutch characteristic curve can be represented in a graph in which the setting position of the friction clutch device, friction clutch or actuator device is plotted on the x-axis and the transmitted torque on the y-axis. A contact point may describe a set position of a friction clutch device, friction clutch and/or actuator device at which the friction clutch initiates transmission of torque upon actuation in the direction from an open actuated position to a closed actuated position. A contact point may describe a set position of a friction clutch device, friction clutch and/or actuator device at which the friction clutch transmits a predetermined torque. The predetermined torque may be, for example, about 2 to 3 Nm. As used herein, the term "contact point" can refer not only to a contact point, but also to a setting position of a friction clutch device, friction clutch and/or actuator device assigned to a contact point. The setting positions of the friction clutch device, the friction clutch and/or the actuator device, assigned to the contact points, can be stored in the memory device.

A path between the open point and the contact point can be determined and a path value can be stored. The opening point may be the point at which the actuator device starts transmitting force or pressure upon actuation of the friction clutch in the opening direction. A route value can be stored in the control device. The path value can be at least largely independent of wear. The value of the opening point may be matched in consideration of the wear condition of the friction clutch. To match the value of the open point, the path value can be subtracted from the value of the contact point subjected to wear. The requested gear range can be taken into account when determining whether the requested gear change can be executed without a reduction in drag torque or whether a reduction in drag torque is necessary. The drag torque state can be determined as either high or low. The drag torque state can be determined in two stages. For determination of the drag torque condition as high or low, a preset limit value may be used. A high drag torque condition can be assigned to a large shifting force required. A low drag torque condition can be assigned to a small shifting force required.

When the drag torque state is determined as low, and/or when the requested shift is a large gear, the requested shift can be directly released. A large gear stage can be allocated to the required large shifting force. Smaller gears can be assigned to the smaller shifting forces required. When the drag torque state is determined as high, and/or when the requested shift is a small gear, the friction clutch is first opened and then the requested shift can be released. The friction clutch can be opened to its open position. The value of the open position may be related to the new state or matched by considering it to the wear state. The open position of the clutch system is determined via the actuator in the leakage position (compensation of the volume into the reservoir is guaranteed), via a mechanical property (e.g. stop or rest) within the clutch or actuator, and/or learned (if Matched according to ) can be defined through the system location.

“Can” indicates a particularly optional feature of the present invention. Accordingly, each embodiment of the present invention including each feature or each feature is provided.

The method according to the invention makes it possible to reduce the drag torque sufficiently. A rapid reduction in drag torque is possible. No active energy supply is required to reduce the drag torque. The friction clutch is opened only when necessary. Shifting time when changing gears is reduced. Driving comfort is increased.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Additional features and advantages form from the detailed description. Detailed features of these embodiments may represent typical features of the present invention. Features of the above embodiments in relation to other features may represent respective features of the present invention.

1 shows a graph of a clutch characteristic curve in a new state of a friction clutch.
2 shows a graph of a clutch characteristic curve in a state of wear of a friction clutch.
Figure 3 shows a graph of the required reduction of the drag torque of the friction clutch.

1 shows a graph 100 of a clutch characteristic curve 102 in a new state of the friction clutch. The friction clutch includes a pressure plate, a contact plate displaceable in an axial direction relative to the pressure plate, and a clutch disk clampable for frictionally coupled power transmission between the pressure plate and the contact plate. The friction clutch includes an input part and an output part. The pressure plate and contact plate belong to the input parts. The friction clutch belongs to the output part. The friction clutch can be operated automatically by an actuator device and an electrical control device. A friction clutch is used in a drive train of a vehicle to be arranged between an internal combustion engine and a manual transmission with gear stages. Friction clutches are wet clutches that operate in oil.

The graph 100 shows the operating path s and the clutch torque M according to the operating path s. At the axial intersection, the actuating path s = 0 and the friction clutch is fully open. In this position, the pressure plate and the contact plate, on the one hand, and the clutch disc, on the other hand, are spaced apart from each other, so that there is no direct frictionally coupled output transmission between the input and output parts of the friction clutch. However, due to the oil present in the friction clutch, even a fully open friction clutch produces a small drag torque due to the fluid. The drag torque depends, for example, on the viscosity and temperature of the oil.

From the fully open position 104 of the friction clutch, the contact plate is displaced in the direction of the pressure plate, so that the friction clutch is actuated in the closed direction due to an increase in the actuating path s. After the passage of the actuating path 106, at the contact point 108, a direct frictionally coupled output transmission between the input and output parts of the friction clutch begins. Also, the drag torque depends on the clearance of the clutch disc from the pressure plate and the contact plate. Thus, the drag torque is increased due to the increase in the actuation path s on the actuation path 106 already before the contact point 108 is reached, even without a direct frictionally coupled power transmission between the input and output parts.

When the friction clutch is operated from the fully open position 104 in the opposite direction to the closed direction, the hydraulic section of the actuator device can reach the leakage position 110 connected to the compensating vessel, so that pressure compensation/volume compensation is possible. .

2 shows a graph 200 of a clutch characteristic curve 202 in a wear condition of a friction clutch. In a wear state, due to wear, a larger actuating path (s) must be traversed until the contact point 204 is reached. From the fully open position 206 of the friction clutch, a path progresses first due to wear to the open point 208, over which the drag torque does not increase despite the increased actuation path s. The increase in drag torque due to the reduced clearance of the clutch disc from the pressure plate and the contact plate occurs only after exceeding the opening point 208 over the actuating path section 210 . From beyond the contact point 204, a direct frictionally coupled power transfer between the input and output components of the friction clutch is initiated. The length of the actuation path section 210 in the worn state approximately corresponds to the length of the actuation path 106 in the new condition according to FIG. 1 . In addition, complementary reference is made in particular to FIG. 1 and the corresponding description.

3 shows a graph 300 of the required reduction in the drag torque of the friction clutch. The actuator device of the friction clutch is controlled by a control device. The flow depicted by graph 300 is executed within the control device.

Taking into account the request 302, a gear shift is changed in the transmission, and considering the drag torque state 304, it is determined whether the requested gear change can be executed without a reduction in drag torque or whether a reduction in drag torque is required. It is decided whether or not

If the drag torque condition 304 is low, and the requested shift is a large gear, then the requested shift change is released directly in step 306. If the drag torque condition 304 is high and/or the requested shift is a small gear, the friction clutch is first opened in step 308 and then the requested shift is released.

Then, depending on the drag torque state 304, either the gear change is directly executed in step 310 or the contact point is first initiated in step 312 and then the gear change is executed.

100: graph
102: Clutch characteristic curve in a new state
104: fully open position
106: working path
108: contact point
110: leak location
200: graph
202: Clutch characteristic curve in worn condition
204: contact point
206: fully open position
208: open point
210: operating path section
300: graph
302: Gear change request
304: drag torque state
306: step
308: step
310: step
312: step

Claims (10)

A method for reducing the drag torque of a wet automotive friction clutch, which is automatically operable between an open position and a closed position during a gear change, comprising:
According to the gear change request 302, firstly, the drag torque state 304 is determined, and then, whether or not the requested gear change can be executed without reducing the drag torque or the drag torque according to the preset limit value of the drag torque. It is determined whether a reduction of
To determine the drag torque state (304), the contact point (108) is determined on the basis of the measured or calculated clutch characteristic curve (102) in the non-wear state of the friction clutch;
A method for reducing drag torque, characterized in that a path (106) between an open point (104) and a contact point (108) is determined and the path value is stored. 2. The drag torque condition (304) of claim 1, wherein the drag torque condition (304) results from measured drag torque, clutch temperature, coolant temperature, energy input into the friction clutch since last shutdown, number of clutch actuations since last shutdown, and simulated wear. Characterized in that the determination is made in consideration of at least one of the operating displacements of the drag torque reduction method. delete delete Method according to claim 1, characterized in that the value of the opening point (208) is matched taking into account the state of wear of the friction clutch. Method according to claim 1, characterized in that, for matching the value of the open point (208), the path value (106, 210) is subtracted from the value of the contact point (204) subject to wear. The method according to claim 1 or 2, wherein when determining whether or not a requested shift stage change according to a preset limit value of the drag torque can be executed without a decrease in the drag torque or whether a decrease in the drag torque is necessary, the request A method for reducing drag torque, characterized in that the shift stage is considered. 3. Method according to claim 1 or 2, characterized in that the drag torque condition (304) is determined as higher or lower than a preset limit value. 8. The drag torque according to claim 7, characterized in that, in at least one of a case where the drag torque state (304) is determined as low and a case where the requested shift is a large gear, the requested shift is directly released. reduction method. 8. The method according to claim 7, wherein in the case of at least one of a case where the drag torque state (304) is determined as being higher than a preset threshold value and a case where the requested shift range is a small gear range, the friction clutch is first opened and then the requested shift shift is performed. A method for reducing drag torque, characterized in that the stage change is released.

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