Vehicle with wheel-end disconnect and associated control method
AssigneeFord Global Technologies, LLC
InventorsJacob Martin Povirk, Mikhail Steinberg
Life of this patent
Estimating the term…
Abstract
One vehicle wheel is disconnected from a differential while the vehicle is in a front wheel drive mode. A controller checks for a malfunction of the differential while the vehicle is in the front wheel drive mode and in response to a request to enter an all wheel drive mode. If speeds of the other vehicle wheel and the differential input indicate that the malfunction is present, the all wheel drive mode is disabled and the driver is informed. If fluid temperature indicates a risk of the malfunction, all wheel drive mode is temporarily disabled and the driver is informed. If the temperature condition continues to be present for a predetermined duration, the all wheel drive mode is disabled.
Claims12
A vehicle comprising:
- a differential having an input shaft, a first axle shaft, and a second axle shaft;
- a first wheel fixedly coupled to the first axle shaft;
- a second wheel selectively coupled to the second axle shaft by a clutch;
- a power take-off unit configured to selectively couple a transaxle output to a driveshaft;
- a rear drive unit configured to selectively couple the driveshaft to the differential input shaft;
- and
- a controller programmed to respond to a request to enter an all wheel drive mode by
- engaging the clutch and power take-off unit only if a ratio of a speed of the input to a speed of the first axle shaft is less than a first threshold and
- inhibiting engagement of the clutch and power take-off unit if the ratio exceeds the first threshold.
A method comprising:
- in a front wheel drive mode, disengaging a clutch to decouple a rear wheel from a first rear axle;
- and
- responding to a request to enter an all wheel drive mode by engaging a power take-off unit to couple a driveshaft to a transaxle output and engaging the clutch only if a ratio of a rear differential input speed to a speed of a second rear axle is less than a threshold.
Dependencies are inferred from the claim text.