Method and device for determination a touch point of a friction clutch
AssigneeZF Friedrichshafen AG
InventorsMartin-Joachim Bader, Karl Locher
Life of this patent
Estimating the term…
Abstract
A method of determining a touch-point of a friction clutch of a motor vehicle that is relevant for control purposes such that a current, actual touch-point of the friction clutch is determined adaptively, and such that the current touch-point is modified, with a correction value that depends on the elasticity of the friction clutch, in order to determine the control-relevant touch-point. The control device comprises elements for carrying out the method.
Claims11
A method of determining a touch-point of a friction clutch of a motor vehicle, with the touch-point being relevant for control purposes, such that a current actual touch-point of the friction clutch is determined adaptively, the method comprising the steps of:
- modifying, with a control device, the current touch-point with a correction value that depends on an elasticity of the friction clutch in order to determine a control-relevant touch-point;
- and
- defining the elasticity of the friction clutch as a function of a relative difference between a value of the current touch-point on a characteristic curve and a value of an inflection point of the friction clutch on the characteristic curve, the friction clutch being more elastic, the greater the relative difference is, and the friction clutch being less elastic, the smaller the relative difference is.
A control device of a motor vehicle for determining a control-relevant touch-point of a friction clutch of the motor vehicle, having a determining means for adaptive determination of a current touch-point of the friction clutch, and for modifying the current touch-point with a correction value that depends on an elasticity of the friction clutch for determining the control-relevant touch-point of the friction clutch, the elasticity of the friction clutch being defined as a relative difference between a value of the current touch-point on a characteristic curve and a value of an inflection point of the friction clutch on the characteristic curve, the friction clutch being more elastic, the greater the relative difference is, and the friction clutch being less elastic, the smaller the relative difference is.
A method of determining a touch-point of a friction clutch of a motor vehicle that is relevant for control purposes, the method comprising the steps of:
- determining a correction value, with an electronic control unit, depending on an elasticity of the friction clutch, the elasticity of the friction clutch being an amount of torque transferred through the friction clutch in relation to a change in pressure of the friction clutch;
- defining the elasticity of the friction clutch as being a relative difference between an amount of pressure of the friction clutch at the touch point of the friction clutch and an amount of pressure of the friction clutch prior to full engagement thereof;
- modifying, with the electronic control unit, a current actual touch-point of the friction clutch with the correction value;
- and
- defining, with the electronic control unit, the modified current actual touch-point as being a control-relevant touch-point.
Dependencies are inferred from the claim text.