Process and device for determining a vehicle's mass

A method for determining a mass value (Mtot) of a motor vehicle having a drive unit and a clutch unit, the mass value (Mtot) representing the mass of a motor vehicle such as a recreational or commercial motor vehicle, the force flow between the drive unit and the vehicle wheels being interruptible by disengaging the clutch unit, the method comprising the steps of:

• detecting at least one first acceleration value (a1) which represents the vehicle acceleration at a first time point at which the clutch unit is engaged;
• detecting at least a first drive value (Fdriv1) which represents the drive force or the drive torque of the drive unit at the first time point;
• detecting at least a second acceleration value (aopen) which represents the vehicle acceleration at a second time point at which the clutch unit is disengaged;
• comparing the detected second acceleration value (aopen) to at least one pregiven threshold value (Su, So);
• determining the mass value (Mtot) at least in dependence upon the comparison and at least in dependence upon the detected first acceleration value (a1) and the detected first drive value (fdriv1);
• and,
• determining at least a first and a second running resistance value (M1, M2) at least in dependence upon two detected first acceleration values (a1, a2) and two detected first drive values (Fdriv1, Fdriv2).

An arrangement for determining a mass value (Mtot), which represents the vehicle mass, for a vehicle having a drive unit and a clutch unit wherein the force flow between the drive unit and the vehicle wheels can be interrupted by disengaging the clutch unit, the arrangement comprising:

• first detecting means for detecting at least a first acceleration value (a1), which represents the vehicle acceleration at a first time point, when the clutch unit is engaged and for detecting at least a second acceleration value (aopen), which represents the vehicle acceleration at a second time point, when the clutch unit is disengaged;
• second detecting means for detecting at least a first drive value (Fdriv1), which represents the drive force or the drive torque of the drive unit at the first time point;
• comparison means for comparing the detected second acceleration value (aopen) to at least one pregivable threshold value (Su, So);
• means for detecting a roadway slope from the comparison of said second acceleration value (aopen) to said at least one pregivable threshold value (Su, So);
• and,
• means for determining the mass value (Mtot) at least in dependence upon said roadway slope and at least in dependence upon the detected first acceleration value (a1) and the detected first drive value (Fdriv1).

An arrangement for determining a mass value (Mtot), which represents the vehicle mass, for a vehicle having a drive unit and a clutch unit wherein the force flow between the drive unit and the vehicle wheels can be interrupted by disengaging the clutch unit, the arrangement comprising:

• first detecting means for detecting at least a first acceleration value (a1), which represents the vehicle acceleration at a first time point, when the clutch unit is engaged and for detecting at least a second acceleration value (aopen), which represents the vehicle acceleration at a second time point, when the clutch unit is disengaged;
• second detecting means for detecting at least a first drive value (Fdriv1), which represents the drive force or the drive torque of the drive unit at the first time point;
• comparison means for comparing the detected second acceleration value (aopen) to at least one pregivable threshold value (Su, So);
• means for determining the mass value (Mtot) at least in dependence upon the comparison and at least in dependence upon the detected first acceleration value (a1) and the detected first drive value (Fdriv1);
• and,
• wherein a determination is made by means of the comparison means as to whether the detected second acceleration value (aopen) lies within an interval (Su, So);
• wherein acceleration values within this interval represent a drive on a roadway which is level;
• wherein it is provided that, when it is determined that the detected second acceleration value (aopen) lies outside of the interval (Su, So), the mass value (Mtot) is determined in dependence upon the detected second acceleration value (aopen) in the sense of a correction caused by the slope of the roadway.