Control of a limited slip differential optimized for slippery driving conditions
AssigneeBombardier Recreational Products Inc.
InventorsFrancois-Charles Dumas, Jean-Philippe Houle
Life of this patent
Estimating the term…
Abstract
A vehicle has an engine, a limited slip differential (LSD) mounted on an axle driven by the engine, and left and right wheels operably connected to the LSD. At least one parameter indicative of a riding condition of the vehicle is determined. A slippery driving condition is detected based on the at least one parameter. The LSD is selectively locked in response to the detection. The slippery driving condition is detected when a torque requested by a user is above a load line of the engine, upon successive wheel slips occurrences, and/or when a wheel slip is detected while a preload is applied to the LSD.
Claims20
A method of controlling a limited slip differential (LSD) of a vehicle, the vehicle having an engine, the LSD, and left and right driven wheels operably connected to the LSD, the method comprising:
- determining at least one parameter indicative of a riding condition of the vehicle;
- based on the at least one parameter, detecting a slippery driving condition;
- selectively locking the LSD when the slippery driving condition is detected;
- determining that a torque of the engine is less than a predetermined torque set-point;
- and
- following the determination that the torque of the engine is less than the predetermined torque set-point, selectively unlocking the LSD.
A method of controlling a limited slip differential (LSD) of a vehicle, the vehicle having an engine, the LSD, and left and right driven wheels operably connected to the LSD, the method comprising:
- determining at least one parameter indicative of a riding condition of the vehicle;
- based on the at least one parameter, detecting a slippery driving condition;
- selectively locking the LSD when the slippery driving condition is detected;
- determining at least one parameter indicative of a riding condition of the vehicle comprises determining a speed of the vehicle and determining a torque of the engine;
- and
- detecting the slippery driving condition comprises determining that the torque of the engine is above a load line of the engine for the speed of the vehicle.
A method of controlling a limited slip differential (LSD) of a vehicle, the vehicle having an engine, the LSD, and left and right driven wheels operably connected to the LSD, the method comprising:
- determining at least one parameter indicative of a riding condition of the vehicle by determining a rotational speed of the left wheel and determining a rotational speed of the right wheel;
- based on the at least one parameter, detecting a slippery driving condition;
- selectively locking the LSD when the slippery driving condition is detected;
- comparing the rotational speeds of the left and right wheels;
- and
- detecting a wheel slip occurrence if a difference between the rotational speeds of the left and right wheels exceeds a predetermined maximum difference in rotational speeds;
- wherein detecting the slippery driving condition comprises:
- preloading the LSD;
- and
- detecting a wheel slip occurrence while the LSD is preloaded.
A differential assembly for use in a vehicle having an engine, left and right driven wheels, a transaxle operatively connected to the left and right driven wheels, a transmission operatively connected to the engine and to the transaxle and configured to transmit torque from the engine to the transaxle for propelling the vehicle, and a shifter operable to select between a reverse gear, a high forward gear and a low forward gear of the transaxle, the differential assembly comprising:
- a limited slip differential (LSD) operatively connectable to a driveshaft and to the left and right driven wheels, the LSD being adapted for transferring torque from the driveshaft to the left and right driven wheels;
- a sensor of at least one parameter indicative of a riding condition of the vehicle;
- and
- a control unit operatively connected to the LSD and to the sensor of the at least one parameter indicative of the riding condition of the vehicle, the control unit being adapted for:
- detecting a slippery driving condition based on the at least one parameter indicative of the riding condition of the vehicle, and
- controlling selective locking of the LSD when the slippery driving condition is detected while one of the reverse gear and the low forward gear of the transaxle is selected.
A method of controlling a limited slip differential (LSD) of a vehicle, the vehicle having an engine, the LSD, and left and right driven wheels operably connected to the LSD, the method comprising:
- detecting a first accelerator control position;
- in response to determining that the first accelerator control position meets or exceeds a predetermined position threshold, applying a predetermined load on the LSD;
- after applying the predetermined load on the LSD, detecting a second accelerator control position;
- and
- in response to determining that the second accelerator control position is less than the predetermined position threshold, selectively releasing the predetermined load on the LSD.
Dependencies are inferred from the claim text.