Vehicle onboard brake pad/lining wear estimators with temperature estimations

• US 20060131950A1
• Filed: 12/20/2004
• Published: 06/22/2006
• Est. Priority Date: 12/20/2004
• Status: Active Grant

• Current Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Original Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Inventors: Larson, Gerald L.
• Granted Patent: US 7,244,003 B2
• Time in Patent Office: Days
• US Class Current: 303/7
• CPC Class Codes: B60T 17/221 Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems hydraulic pressure systems in general F15B19/00, F15B21/04; testing structures or apparatus G01M
• CPC Class Codes: B60T 8/00 Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force by changing number of effective brake cylinders in power brake systems B60T17/10
• CPC Class Codes: F16D 2066/006 without direct measurement of the quantity monitored, e.g. wear or temperature calculated form force and duration of braking
• CPC Class Codes: F16D 66/02 Apparatus for indicating wear

Abstract

The brake lining and wear estimation system operates using extant vehicle sensors such as those used to implement height and stability control systems or anti-lock brake systems. This minimizes, or eliminates, the need to modify the brake units themselves. Compressed air systems used on heavy duty vehicles to support the operation of various systems, including air brakes, provide pressure monitoring features in various pneumatic circuits, which can be monitored to estimate brake lining application pressure or vehicle loading. Vehicle speed and brake actuation periods are derived from other commonly employed sensors. Data collected from the sensors is supplied to a central, programmable computer over a data bus to generate the heat and wear estimates.

Claims

1. Apparatus for estimating brake lining wear and operating in a plurality of brake units for a vehicle, the apparatus comprising:

a source of temperature readings exogenetic to the plurality of brake units;

a plurality of independent brake actuators;

a central source of pressurized actuation fluid connected to each of the plurality of independent brake actuators;

a vehicle body computer;

a source of a brake signal coupled to the vehicle body computer;

a brake controller for generating brake actuation signals for application to the independent brake actuators;

a vehicle data bus connected between the brake controller and the vehicle body computer for two way data communication between the brake controller and the vehicle body computer including communication of the brake signal from the vehicle body computer to the brake controller, the brake controller being responsive to the brake signal for generating brake actuation signals;

a source of a signal indicative of activation of the brake units coupled to the vehicle body computer;

a source of indication of vehicle wheel speed coupled to the vehicle body computer; and

the vehicle body computer being programmed to collect the exogenetic temperature signal, vehicle speed data and the signal indicative of activation of the individual brake units for determining wear and temperature for the linings of the brake units.

2. Apparatus as described in claim 1, wherein the source of the signal indicative of the activation of the individual brake units comprises a pressure sensor in communication with a fluidic actuation line connected to each individual brake unit and means for communicating pressure signals from each pressure sensor to the vehicle body computer.

3. Apparatus as described in claim 2, further comprising:

the vehicle body computer being further programmed to determine from the pressure signals duration of brake actuation for each brake unit and to use the pressure signal in combination with wheel speed to determine wear and temperature of the lining for each brake unit.

4. Apparatus as described in claim 1, further comprising:

a vehicle height controller providing pressure signals related to loading of axles of the vehicle; and

the vehicle body computer being further programmed to determine axle loading from the pressure signals and to determine changes in vehicle kinetic energy from computational combination of vehicle loading and changes in the wheel velocity signals.

5. Apparatus as described in claim 4, further comprising:

the vehicle body computer being programmed to determine changes in vehicle kinetic energy attributable to brake actuation responsive to the actuation related signals and, responsive to exogenetic temperature and changes in kinetic energy attributed to brake operation for calculating an estimate of brake lining wear and temperature.

6. A brake lining and wear estimation system comprising:

such extant vehicle sensors as present on a motor vehicle that are used to implement height and stability control systems or anti-lock brake systems, including air spring pressure sensors, brake fluidic actuation circuit pressure sensors, a compressed air tank pressure sensor and wheel velocity sensors;

a vehicle body computer;

at least a first controller for vehicle systems including an anti-lock braking system and a vehicle height and stability control system;

a vehicle controller area network providing coupling of data between the vehicle body computer and the controllers; and

the vehicle body computer being programmed to integrate data from the controllers to provide an estimate of brake lining wear and temperature.

7. A brake lining and wear estimation system as claimed in claim 6, further comprising:

the data integration program utilizing brake fluidic actuation circuit pressure readings for determining brake actuation duration for individual brake units and lining pressure against a brake rotor or drum in a functional relationship for estimating brake lining temperature and wear.

8. A brake lining and wear estimation system as claimed in claim 7, further comprising:

the data integration program utilizing signals from air spring pressure sensors for determining axle loading and combining the determined axle loading with a vehicle speed estimate for determining vehicle kinetic energy and changes in vehicle kinetic energy.

9. A brake lining and wear estimation system as claimed in claim 8, further comprising:

the data integration program being further responsive to brake actuation signals for allocating portions of negative changes in kinetic energy to discrete brake units and calculating an estimate from the allocated portions of changes in brake lining temperature and wear.