Method and arrangement for automatically determining the differential gear ratio

In a motor vehicle having a transmission having an output shaft and wheels operatively connected to said transmission, a method for automatically determining the specific rpm ratio (iDiff) between said output shaft of said transmission and said wheels, the method comprising the steps of:

• detecting a first rpm value (Nij) representing the rpm of at least one of said wheels;
• detecting a second rpm value (Nab) representing the rpm of said output shaft of said transmission;
• determining a preliminary value (iDiffv) for said rpm ratio (iDiff) in dependence upon said detected rpm values (Nij, Nab) when at least one of said rpm values (Nij, Nab) exceeds a pregivable threshold value (SW1);
• forming a driving state quantity (FZ) representing a driving state of said motor vehicle;
• determining a pregivable operating state to be present when said driving state quantity (FZ) represents a driving state which is essentially a steady state driving state;
• and,
• determining said rpm ratio (iDiff) in dependence upon the detected rpm values (Nij, Nab) when said pregivable operating state is present.

In a motor vehicle having a transmission and wheels operatively connected to said transmission, a method for automatically determining the specific rpm ratio (iDiff) between said transmission and said wheels, the method comprising the steps of:

• detecting a first rpm value (Nij) representing the rpm of at least one of said wheels;
• detecting a second rpm value (Nab) representing the rpm of a component of said transmission;
• determining a preliminary value (iDiffv) for said rpm ratio (iDiff) in dependence upon said detected rpm values (Nij, Nab) when at least one of said rpm values (Nij, Nab) exceeds a pregivable threshold value (SW1);
• forming a driving state quantity (FZ) representing a driving state of said motor vehicle;
• determining a pregivable operating state to be present when said driving state quantity (FZ) represents a driving state which is essentially a steady state driving state;
• and,
• determining said rpm ratio (iDiff) in dependence upon the detected rpm values (Nij, Nab) when said pregivable operating state is present;
• storing at least one of the following:
• (a) said specific rpm ratio (iDiff);
• and,
• (b) said preliminary rpm ratio (iDiffv);
• applying said rpm ratio to control (open loop and/or closed loop) the transmission functions;
• and,
• replacing said preliminary rpm ratio (iDiffv) with said specific rpm ratio (iDiff);
• the determination of said specific rpm ratio (iDiff) and/or the determination of said preliminary rpm ratio (iDiffv) occurs with pregiven frequency (N0);
• and, said determination occurs together with a new service introduction of a control unit for controlling (open loop and/or closed loop) the functions of said transmission.

In a motor vehicle having a transmission having an output shaft and wheels operatively connected to said transmission, an arrangement for automatically determining the rpm ratio (iDiff) between said output shaft of said transmission and said wheels, the arrangement comprising:

• first means for detecting a first rpm value (Nij) representing the rpm of at least one of said wheels;
• second means for detecting a second rpm value (Nab) representing the rpm of said output shaft of said transmission;
• means for forming a driving state quantity (FZ) representing a driving state of said motor vehicle;
• means for determining a pregivable operating state to be present when said driving state quantity (FZ) represents a driving state which is essentially a steady state driving state;
• and,
• means for determining said rpm ratio (iDiff) in dependence upon the detected rpm values when said pregivable operating state is determined.

In a motor vehicle having a transmission having an output shaft and wheels operatively connected to said transmission, an arrangement for automatically determining the rpm ratio (iDiff) between said output shaft of said transmission and said wheels, the arrangement comprising:

• first means for detecting a first rpm value (Nij) representing the rpm of at least one of said wheels;
• second means for detecting a second rpm value (Nab) representing the rpm of said output shaft of said transmission;
• means for determining a preliminary value (iDiffv) for said rpm ratio (iDiff) in dependence upon said detected rpm values (Nij, Nab) when at least one of said rpm values (Nij, Nab) exceeds a pregivable threshold value (SW1);
• means for forming a driving state quantity (FZ) representing a driving state of said motor vehicle;
• means for determining a pregivable operating state to be present when said driving state quantity (FZ) represents a driving state which is essentially a steady state driving state;
• and,
• means for determining said rpm ratio (iDiff) in dependence upon the detected rpm values (Nij, Nab) when said pregivable operating state is present.