Four-wheel drive vehicle control system and methods
AssigneeWarn Automotive, LLC
InventorsKevin M. Christensen, Oliver Blake Randall, Christopher James Boudreau
Life of this patent
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Abstract
Methods and systems are provided for operating a four-wheel drive powertrain of a vehicle. In one example, a method may comprise: in response to a desired shift from a four-wheel drive mode to a two wheel-drive mode: decreasing a transfer case torque output to a secondary driveline to a lower first level and disengaging a disconnect device of the secondary driveline; increasing the transfer case torque output from the lower first level to a higher second level over a duration; and after the duration, reducing the transfer case torque.
Claims20
A method comprising:
- responsive to a desired shift from a four-wheel drive mode to a two-wheel drive mode:
- decreasing a transfer case torque output to a secondary driveline to a lower first level and disengaging a disconnect device of the secondary driveline;
- increasing the transfer case torque output from the lower first level to a higher second level;
- and
- reducing the transfer case torque output from the higher second level to decouple the secondary driveline.
A system comprising:
- a vehicle powertrain comprising:
- an engine;
- a transfer case;
- a primary driveline including a first pair of wheels, the primary driveline drivingly coupled to the engine;
- a secondary driveline including a second pair of wheels, the secondary driveline selectively coupled to the engine via the transfer case;
- a secondary driveline disconnect positioned in the secondary driveline;
- and
- a controller with computer readable instructions stored in non-transitory memory for:
- engaging the engine and secondary driveline when a shift from a two-wheel drive mode to a four-wheel drive mode is desired;
- and
- disengaging, and then re-engaging for a duration, before again disengaging the secondary driveline and engine when a shift from the four-wheel drive mode to the two-wheel drive mode is desired.
A method comprising:
- increasing a transfer case coil voltage from a lower first level to a higher second level when shifting from a two-wheel drive mode to a four-wheel drive mode and then adjusting the coil voltage based on vehicle operating conditions in the four-wheel drive mode;
- and
- stepping down the coil voltage to the lower first level, then increasing the coil voltage from the lower first level to the higher second level, and then stepping down the coil voltage from the higher second level to the lower first level when shifting from a four-wheel drive mode to a two-wheel drive mode, and then maintaining the coil voltage at the lower first level in the two-wheel drive mode.
Dependencies are inferred from the claim text.