Vehicle transmission control system
AssigneeZahnraderfabrik Renk A.G.
InventorsFranz X. Zaunberger, Artur Kugler
Life of this patent
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Abstract
A control system for an automatic vehicle transmission includes a clutch mechanism interconnecting the driving connection between the vehicle engine and the vehicle driving wheels. The control system operates to automatically disengage the clutch when the braking system is actuated and the vehicle speed is reduced to a predetermined level with the accelerator in idle position. The clutch automatically engages when any of the three parameters have changed from predetermined levels. The automatic control system serves to reduce fuel consumption and exhaust emissions at vehicle idling by reducing transmission drag, yet provides smooth shifting and permits the engine and transmission to assist in vehicle braking.
Claims10
A transmission control system adapted for controlling the operation of a vehicle automatic transmission having a fluid coupling and means for interrupting the driving connection between a vehicle engine and a transmission output shaft, the control system including vehicle speed sensing means, brake sensing means for detecting when the vehicle brakes have been applied, control means, and means interconnecting the speed sensing means and the brake sensing means to the control means, the control means including means actuating the interrupting means when the speed sensing means indicates that the vehicle speed is at or below a predetermined value and simultaneously the brake sensing means indicates that a minimum predetermined braking force has been applied, the means for actuating the interrupting means including means for restoring the driving connection prior to complete release of braking force whereby reduced engine load will be achieved with smooth vehicle operation during braking and subsequent acceleration.
A method of controlling a vehicle automatic transmission clutch which is operable to interrupt the driving connection between a vehicle engine and a transmission output shaft comprising the steps of:
- (a) monitoring the vehicle speed and detecting when the vehicle speed is at or below a predetermined value,
- (b) monitoring the condition of the vehicle braking system and detecting when the vehicle brakes have been applied,
- (c) disengaging the clutch when both the detected speed is less than or equal to the predetermined value and, at the same time, the vehicle brakes have been applied, and
- (d) reengaging the clutch when the vehicle is stopped during release of the vehicle brakes prior to complete release.
Dependencies are inferred from the claim text.