Transmission clutch control arrangement
AssigneeVolkswagen Aktiengesellschaft
InventorsNorbert Ramm, Frank Zimmermann
Life of this patent
Estimating the term…
Abstract
An arrangement for the controlled engagement and disengagement of a clutch in the transmission of a motor vehicle drive system includes an engine and an automatic transmission which can be activated electro-hydraulically. In order to avoid "stationary-state shaking", a preselected value for the clutch slip torque is determined as a function of a prehistory of limited duration in the form of an evaluation of the speed profile of the motor vehicle in the immediate past.
Claims21
A method for controlling engagement of a clutch to which engagement pressure is applied in the transmission of a drive system for a motor vehicle which includes a body, drive wheels, a drive system including an automatic transmission containing a clutch transmission, a control system and an arrangement for generating a signal representing at least one of:
- (a) a torque bias between a component of the drive system and the vehicle body;
- (b) a displacement distance between the drive system and the vehicle body;
- (c) an output torque of the transmission;
- and (d) a supporting force in the support bearings of a component of the drive system, and supplying the signal to the transmission control system comprising:
- setting the control pressure on the clutch in the transmission (a) when the motor vehicle is in a stationary state, a gear is engaged and driven wheels are braked, or (b) when the motor vehicle in a stationary state with no gear engaged, or (c) when the motor vehicle is decelerating to a standstill with a gear engaged and when the vehicle speed and load are below specified thresholds as a function of the torque bias in such a way that, when a preselected clutch slip torque value is exceeded, the clutch begins to slip;
- wherein the preselected value for the clutch slip torque is determined as a function of a prehistory of the vehicle operation during a limited period in the form of an evaluation of an immediately preceding vehicle speed profile.
Apparatus for controlling the engagement of a clutch in a motor vehicle comprising:
- a motor vehicle including a body,
- a drive system which includes an engine and an automatic transmission and is connected by resilient supports to the body of the motor vehicle,
- a differential connected to the drive system,
- axle shafts connected to the differential and to driven wheels having wheel brakes,
- a transmission control system which is connected to a control device for controlling the connection of the gear elements of the transmission;
- at least one sensor for measuring (a) a displacement of the drive system with respect to the vehicle body or (b) the torque of a transmission output shaft or (c) a supporting force in or on the supporting bearings or (d) a throttle valve angle on an engine throttle valve, or (e) a brake light switch, or (f) the vehicle speed, wherein the transmission control system is responsive to signals from at least one of (a) a sensor for detecting the rotational speed of the engine, (b) a switch for determining the position of a selector lever of the automatic gearbox, (c) a manually settable activation element for setting a preselected value for the clutch slip torque, (d) a handbrake switch, (e) an engine hood switch, (f) a seat contact switch in the driver's seat, and (g) a door switch.
Dependencies are inferred from the claim text.