Method for determining a road friction value
AssigneeMagna PT B. V. & Co. KG
InventorsSebastian Crump, Sören Wenzel
Life of this patent
Estimating the term…
Abstract
A method for determining a current road friction value (μroad) using a control device in a motor vehicle continuously calculates a current friction value demand (μdem) by the control device. A current tire stiffness (St) is determined from the calculated current friction value demand (μdem) and a current tire slip (Slip), and the current road friction value (μroad) is determined from the current tire stiffness (St) by way of a stored table (T), which maps tire stiffnesses (St) to road friction values (μroad).
Claims15
A method for determining a current road friction value by a control unit in a motor vehicle, the method comprising:
- continuously calculating, by the control unit, a current friction value demand from a current driving wheel torque and a currently prevailing axle load, determining a current tire stiffness from the calculated current friction value demand and a current tire slip, and determining a current road friction value from the current tire stiffness by way of a stored table, which maps tire stiffness to road friction values;
- wherein in the event of a loss of traction, the current road friction value is determined, from the current friction value demand, as equal to the current friction value demand.
A method for determining a current road friction value by a control unit in a motor vehicle, the method comprising:
- continuously calculating, by the control unit, a current friction value demand from a current driving wheel torque and a currently prevailing axle load, determining a current tire stiffness from the calculated current friction value demand and a current tire slip, and determining a current road friction value from the current tire stiffness by way of a stored table, which maps tire stiffness to road friction values:
- wherein the stored table, which maps tire stiffnesses to road friction values, is adjusted in the event of a loss of traction.
A method for determining a current road friction value by a control unit in a motor vehicle, the method comprising:
- continuously calculating, by the control unit, a current friction value demand from a current driving wheel torque and a currently prevailing axle load, determining a current tire stiffness from the calculated current friction value demand and a current tire slip, and determining a current road friction value from the current tire stiffness by way of a stored table, which maps tire stiffness to road friction values;
- wherein at a first time, the actual road friction value is higher than the current friction value demand;
- at a second time, later than the first time, a loss of traction is detected;
- at or after the second time, determining that the actual road friction at the second time corresponds to the current friction value demand at the second time;
- in response thereto, adjusting the determined road friction value to the actual road friction value;
- adapting a friction curve of the vehicle based on the determined road friction road friction value.
Dependencies are inferred from the claim text.