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US 2015/0105992 A1Published application
Vehicle drive train control method and system
AssigneeVolvo Lastvagnar AB
InventorsLena Larsson, Jan Öberg, Filip Alm
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AssigneeVolvo Lastvagnar AB
InventorsLena Larsson, Jan Öberg, Filip Alm
Estimating the term…
A vehicle traction system includes a first traction wheel forming part of a first propulsion system including a mechanical drive train, a second traction wheel forming part of a second propulsion system including a hydraulic pump for powering a hydraulic motor, one sensor indicating a take-off condition, and a control unit for controlling the second propulsion unit. The control unit is programmed to automatically detect a take-off condition by the sensor and send an input to the control unit that a take-off condition is fulfilled, automatically provide a traction force from the second propulsion system in response to the indication that there is a take-off condition of the vehicle present and an indication that a traction is or will be provided by the first traction system, and automatically control the second propulsion unit by the control unit in dependence of the manually controlled torque from the first propulsion unit.
A method for controlling a traction system (1) of a vehicle, said system comprising
A method according to any previous claim, characterized in that the torque from the second propulsion unit (13) during take-off is controlled in dependence of at least one of load on the second traction wheel (6a), a friction coefficient between ground and the second traction wheel (6a), a maximum allowable slip of the second traction wheel (6a) or a steering angle of the second traction wheel (6a).
A method according to any previous claim, characterized in that said indication that a traction is or will be provided by the first traction system comprises the engagement of a clutch arranged to transmit torque between the internal combustion engine (4) and the gearbox (5).
A method according to any previous claim, characterized in that said indication that a traction is or will be provided by the first traction system comprises a gear shift of the gearbox (5) from neutral to a forward or reverse gear at standstill.
A method according to any previous claim, characterized in that said indication that a traction is or will be provided by the first traction system is the acceleration from standstill.
A method according to any previous claim, characterized in that there is a fixed minimum torque provided by the second propulsion system when the automatic take-off aid control system is activated and provide this torque until the torque from the mechanically driven wheels is above a certain limit where after the torque from the second propulsion system will increase and be proportional to the torque from the first propulsion system.
A method according to any previous claim, characterized in that the torque from second propulsion system will only continue until the speed of the vehicle is above a certain limit.
A method according to any previous claim, characterized in that the drive train control system comprises sensors concerning traction of one or several wheels, e.g speed sensors for the individual wheels and a vehicle speed sensor, such that traction from the wheels are sensed and slip may be detected such that the control is programmed to reduce the torque onto the surface from the wheel(s) connected to the second, hydraulic traction system if there is a slip detected on the hydraulically driven wheels.
A method according to any previous claim characterized in that said hydraulic pump (7) in the hydraulic propulsion system (13) is a reversible variable displacement pump.
A traction system (1) of a vehicle, said system comprising
A traction system (1) for a vehicle according to claim characterized in that said hydraulic pump (7) is connected to an output shaft of said internal combustion engine (4).
Dependencies are inferred from the claim text.