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US 8,050,835 B2Granted
Method and apparatus for clutch pressure control
AssigneeAllison Transmission, Inc.
InventorsThomas H. Wilson, Charles F. Long, Travis A. Brown
Life of this patent
Estimating the term…
Abstract
A method, apparatus and system for controlling transmission clutch system output pressures is provided. A transmission control unit and a pressure control device including an electro-hydraulic valve and a pressure switch cooperate to provide self-calibrating clutch pressure control systems.
Claims21
A method for calibrating a clutch pressure control system of an automatic transmission of a vehicle, comprising:
- obtaining at least one reference output pressure value and at least one reference electrical input value related to the reference output pressure value for a pressure control device in an operating range of an automatic transmission of a vehicle,
- actuating a pressure switch coupled to the pressure control device to obtain an actual electrical input value corresponding to the reference output pressure value,
- calculating an offset between the reference electrical input and the actual electrical input, and
- applying the offset to the at least one reference electrical input value.
1 more element
An apparatus for controlling a transmission clutch pressure, the apparatus comprising
- a hydraulic fluid supply,
- an electro-hydraulic pressure control valve coupled to the hydraulic fluid supply,
- a pressure switch coupled to the electro-hydraulic pressure control valve, and
- pressure control valve, monitor the pressure switch, compare at least one selected electrical input to at least one reference electrical input, and selectively modify the at least one reference electrical input.
1 more element
Dependencies are inferred from the claim text.