Torque based transfer case control

• Main Authors: RODRIGUES ASHOK, GLAB JOHN A, TODD MATT
• Format: Patent
• Language: English
• Published: 14.02.2008
• Subjects: ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS INVEHICLES; ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OFTRANSMISSIONS IN VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GASEXHAUST OR FUEL SUPPLY OF PROPULSION UNITS, IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE ORDIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; PERFORMING OPERATIONS; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TOTHE CONTROL OF A PARTICULAR SUB-UNIT; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TRANSPORTING; VEHICLES IN GENERAL

A method for controlling operation of a transfer case clutch in a motor vehicle driveline controlled by an engine throttle having a variable position. The transfer case transmits rotating power to a primary power path and to a secondary power path in response to an electric current duty cycle applied to a coil that actuates the clutch. The method includes the steps of determining that a current vehicle speed is less than a reference vehicle speed; determining that the engine throttle position is in a reference throttle position range; determining that a change in vehicle speed is greater than a reference change in vehicle speed; using a current magnitude of torque in the driveline to determine a desired duty cycle for the coil; and applying a duty cycle of the desired magnitude to the coil.