Method and device for determining wear of a carbon ceramic brake disc in a vehicle by impedance measurements
AssigneeProceq SA
InventorsNicola Ramagnano, Johannes Hoffmann, Alessandro Mortara
Life of this patent
Estimating the term…
Abstract
A quality value for a carbon ceramic brake disc (2) in a vehicle is measured by means of a measuring device (3) installed in the vehicle. The measuring device (3) with a coil (10) is located at a distance (d) from the brake disc (2) in order avoid direct physical contact with the brake disc. The impedance of the coil (10) is measured for at least two frequencies. The resulting measurement values that correlate to impedance values are introduced into a mathematical model in order to eliminate the dependence of the unknown distance (d) and to obtain a quality value dependent on the conductivity of the brake disc (2).
Claims15
A method for determining a wear-dependent quality value M of a carbon ceramic brake disc in a vehicle, wherein said quality value M depends monotonously on a conductivity s of said brake disc, said method comprising:
- applying a voltage to a coil having an impedance Z, with said coil being at a distance d from said brake disc,
- performing measurements of a parameter P that is a function of said impedance Z, said distance d and said conductivity s, wherein values Pi of said parameter P are measured at N different frequencies fi with i=1 to N and N>1, and
- fitting a mathematical model describing said parameter P as a function of said frequencies fi, said distance d and said conductivity s to said measurements by varying said distance d and said conductivity s, and
- deriving said quality value M from a value of said conductivity s as obtained from fitting said mathematical model.
A device for determining wear of a carbon ceramic brake disc in a vehicle by obtaining a quality value M depending on a conductivity s of said brake disc, said device comprising:
- a coil with an impedance Z and
- a control unit, wherein said control unit is structured and adapted to
- apply a voltage to said coil,
- perform measurements of a parameter P that is a function of said impedance Z, a distance d between said coil and said brake disc, and said conductivity s, wherein values Pi of said parameter P are measured at N different frequencies fi with i=1 to N and N>1, and
- fit a mathematical model describing said parameter P as a function of said frequencies fi, said distance d and said conductivity s to said measurements by varying said distance d and said conductivity s.
Dependencies are inferred from the claim text.