Method and control unit for determining the probability of failure of a motor-vehicle component

• US 20040034504A1
• Filed: 04/11/2003
• Published: 02/19/2004
• Est. Priority Date: 04/11/2002
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Ulrich, Dieter, Scheffold, Andreas, Haydn, Wolfgang, Bacher-Hoechst, Manfred, Eppinger, Dieter
• Granted Patent: US 6,873,917 B2
• Time in Patent Office: Days
• US Class Current: 702/181
• CPC Class Codes: F02D 2041/224 Diagnosis of the fuel system
• CPC Class Codes: F02D 2041/225 Leakage detection
• CPC Class Codes: F02D 2200/0604 Estimation of fuel pressure
• CPC Class Codes: F02D 2250/04 Fuel pressure pulsation in common rails
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/3836 Controlling the fuel pressure
• CPC Class Codes: F02M 63/0225 Fuel-injection apparatus having a common rail feeding several injectors F02M63/0003 takes precedence; Means for varying pressure in common rails; Pumps feeding common rails

Abstract

A method and control unit for determining the failure probability of a component of a motor-vehicle. Data in the form of damage-relevant influence parameters, which affect the failure probability of the component, are measured and stored during the operation of the component. To ascertain the failure probability, a collective loading is calculated as a determining influence parameter for establishing the fatigue limit of the component. To determine the collective loading as realistically as possible and therefore determine the failure probability as accurately as possible, the influence parameters may be evaluated during the operation of the component, in a control unit of the motor-vehicle for determining the failure probability.

Claims

1. A method for determining a failure probability of a component of a motor vehicle, the method comprising:

monitoring data in the form of damage-relevant influence parameters, which affect the failure probability of the component;

storing the data during operation of the component; and

evaluating the influence parameters in a control unit of the motor vehicle to determine the failure probability during the operation of the component.

2. The method of claim 1, wherein the failure probability is determined within a scope of the evaluating of the influence parameters, by comparing a collective-damage sum, which is a measure of an accumulated loading of the component that is determined with the aid of the influence parameters, and a tolerable-damage sum of the component determined in preliminary stages of the evaluating of the influence parameters.

3. The method of claim 2, wherein the collective-damage sum is determined within the scope of the evaluating of the influence parameters, with the aid of a linear damage-accumulation hypothesis according to Palmgren-Miner, as a function of a collective loading which is a measure of an accumulated loading of the component that is determined using the influence parameters, and as a function of a Woehler component-part curve, which is a measure of the loading capacity of the component.

4. The method of claim 3, wherein the collective loading is calculated within the scope of the evaluating of the influence parameters, as a function of a loading-time function, which is recorded within a framework of the evaluating of the influence parameters, using the influence parameters.

5. The method of claim 4, wherein, within the scope of evaluating the influence parameters, a rainflow matrix, in which information regarding the accumulated loading of the component is stored, may be set up as a function of the loading-time function.

6. The method of claim 2, wherein the tolerable damage sum of the component is determined according to a linear damage-accumulation hypothesis of Palmgren-Miner, as a function of a Woehler component-part curve, which is determined in preliminary stages of the evaluating of the influence parameters and is a measure of the loading capacity of the component, and as a function of a tolerable loading of component parts of the component determined in the preliminary stages of the evaluating of the influence parameters.

7. The method of claim 1, wherein the failure probability is determined for the component which is one of:

at least one of a direct-injecting fuel-injection system and a common-rail fuel-injection system of an internal combustion engine; and

a braking system of a motor vehicle.

8. The method of claim 7, wherein the collective-damage sum and the tolerable-damage sum are each determined for at least one of a joint common rail, an injector body, a housing of a high-pressure pump, and a cylinder head of the high-pressure pump.

9. The method of claim 7, wherein an injection pressure prevailing in the fuel-injection system is measured and stored as one of the influence parameters during operation of the fuel-injection system.

10. A memory element comprising:

at least one of a read-only memory, a random-access memory, and a flash memory, for a control unit for controlling a motor-vehicle function implementable by a least one component; and

a computer program, which is executable on one of a computing arrangement and a microprocessor of the control unit, to perform the following;

monitoring data in the form of damage-relevant influence parameters, which affect the failure probability of the at least one component, and storing the data during operation of the at least one component; and

during the operation of the at least one component, evaluating the influence parameters in a control unit of the motor vehicle to determine the failure probability.

11. A control unit for controlling a motor-vehicle function implementable by at least one component, comprising:

an arrangement to measure and store data in the form of damage-element influence parameters, which affect a failure probability of the component during operation of the component; and

an arrangement to evaluate the influence parameters for determining the failure probability of the component.

12. The control unit of claim 11, wherein the control unit includes an arrangement to determine the failure probability within a scope of the evaluating of the influence parameters, by comparing a collective-damage sum, which is a measure of an accumulated loading of the component that is determined with the aid of the influence parameters, and a tolerable-damage sum of the component determined in preliminary stages of the evaluating of the influence parameters.

13. The control unit of claim 12, wherein the collective-damage sum is determined within the scope of the evaluating of the influence parameters, with the aid of a linear damage-accumulation hypothesis according to Palmgren-Miner, as a function of a collective loading which is a measure of an accumulated loading of the component that is determined using the influence parameters, and as a function of a Woehler component-part curve, which is a measure of the loading capacity of the component.

14. The control unit of claim 13, wherein the collective loading is calculated within the scope of the evaluating of the influence parameters, as a function of a loading-time function, which is recorded within a framework of the evaluating of the influence parameters, using the influence parameters.

15. The control unit of claim 14, wherein, within the scope of evaluating the influence parameters, a rainflow matrix, in which information regarding the accumulated loading of the component is stored, may be set up as a function of the loading-time function.

16. The control unit of claim 12, wherein the tolerable damage sum of the component is determined according to a linear damage-accumulation hypothesis of Palmgren-Miner, as a function of a Woehler component-part curve, which is determined in preliminary stages of the evaluating of the influence parameters and is a measure of the loading capacity of the component, and as a function of a tolerable loading of component parts of the component determined in the preliminary stages of the evaluating of the influence parameters.

17. The control unit of claim 11, wherein the failure probability is determined for the component which is one of:

at least one of a direct-injecting fuel-injection system and a common-rail fuel-injection system of an internal combustion engine; and

a braking system of a motor vehicle.

18. The control unit of claim 17, wherein the collective-damage sum and the tolerable-damage sum are each determined for at least one of a joint common rail, an injector body, a housing of a high-pressure pump, and a cylinder head of the high-pressure pump.

19. The control unit of claim 17, wherein an injection pressure prevailing in the fuel-injection system is measured and stored as one of the influence parameters during operation of the fuel-injection system.