FAULT DIAGNOSIS

• US 20070299574A1
• Filed: 06/19/2007
• Published: 12/27/2007
• Est. Priority Date: 06/22/2006
• Status: Active Grant

• Current Assignee: Scania CV AB (Volkswagen AG)
• Original Assignee: Scania CV AB (Volkswagen AG)
• Inventors: Nyberg, Mattias
• Granted Patent: US 8,219,275 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: G06F 11/2257 using expert systems

Abstract

Status of an entity having a plurality of components is determined from a listing of enhanced diagnostic expressions. For each combination of diagnostic expressions, a current joint diagnostic expression is generated representing a conjunction of first and second diagnostic expressions from respective first and second received listings. This expression is compared with each diagnostic expression in a generated listing of enhanced diagnostic expressions, and is discarded if: there exists a previous expression in the listing that implies the previous expression or there exists either a first or second diagnostic expression in the respective first or second listing that has not yet been included in a joint diagnostic expression and the current joint diagnostic expression implies either the first or second diagnostic expression. Any other joint diagnostic expressions are stored in the listing of enhanced diagnostic expressions. A status report is generated based on the listing of enhanced diagnostic expressions.

Claims

1. A diagnosis engine (100) for estimating a status of an entity (150, 200) with a plurality of components (c₁, . . . , c_n) which each is assumed to be in a fault-free mode or be in exactly one of at least one fault mode, the diagnosis engine (100) comprising a processing unit (110) adapted to receive diagnostic expressions (D, E) indicating at least one of said modes for at least one of said components (c₁, . . . , c_n), and generate a status report (R[Q]) based on the diagnostic expressions (D, E), wherein the diagnosis engine (100) comprises:

a first storage area (120) adapted to store a first listing (D) of diagnostic expressions (D₁, . . . , D_n) constituting a first part of said diagnostic expressions, and store a second listing (E) of diagnostic expressions (E₁, . . . , E_m) constituting a second part of said diagnostic expressions, and

a second storage area (130) adapted to store a listing of enhanced diagnostic expressions (Q) indicating at least one of said modes for at least one of said components (c₁, . . . , c_n), and the processing unit (110) is adapted to;

receive said first listing (D),

receive said second listing (E),

store the first and second listings (D;

E) in the first storage area (120),

create an empty listing of enhanced diagnostic expressions (Q) by clearing any contents of the second storage area (130), and thereafter, for each combination of diagnostic expressions (D_i, E_j) in the first and second listings (D;

E),

generate a current joint diagnostic expression (Q_new) representing a conjunction of a first diagnostic expression (D_i) from the first listing (D) and a second diagnostic expression (E_j) from the second listing (E),

compare the current joint diagnostic expression (Q_new) with each diagnostic expression in the listing of enhanced diagnostic expressions (Q) stored in the second storage area (130),

discard the current joint diagnostic expression (Q_new), if there exists a previous expression (Q_k) in the listing of enhanced diagnostic expressions (Q), and the current joint diagnostic expression (Q_new) implies the previous expression (Q_k),

discard the current joint diagnostic expression (Q_new), if there exists a first diagnostic expression (D_k) in the first listing (D), the first diagnostic expression (D_k) having not yet been included in a joint diagnostic expression and the current joint diagnostic expression (Q_new) implies the first diagnostic expression (D_k),

discard the current joint diagnostic expression (Q_new) if there exists a second diagnostic expression (E_k) in the second listing (E), the second diagnostic expression (E_k) having not yet been included in a joint diagnostic expression and the current joint diagnostic expression (Q_new) implies the second diagnostic expression (E_k), otherwise

store the joint diagnostic expression (Q_new) as an addition to the listing of enhanced diagnostic expressions (Q) in the second storage area (130), and

generate a status report (R[Q]) based on the listing of enhanced diagnostic expressions (Q).

2. The diagnosis engine (100) according to claim 3, wherein the processing unit (110) is adapted to receive at least one of the first and second listings (D;

E) from at least one sensor unit being associated with at least one of said components (c₁, . . . , c_n), said at least one listing (D;

E) reflecting test results in respect of at least one of said components (c₁, . . . , c_n) to which the at least one sensor unit is associated.

3. The diagnosis engine (100) according to claim 1, wherein the processing unit (110) is adapted to receive at least one of the first and second listings (D;

E) from at least one auxiliary diagnosis engine being associated with at least a sub-group of said components (c₁, . . . , c_n), said at least one listing (D;

E) including status reports in respect of the sub-group of said components (c₁, . . . , c_n) to which the at least one auxiliary diagnosis engine is associated.

4. A motor vehicle (200) consisting of a plurality of components (c₁, . . . , c_n, . . . , c_s) and a diagnosis system adapted to estimate a respective status of at least a sub-group (c₁, . . . , c_n) of said components, wherein the diagnosis system comprises the diagnosis engine (100) according to any one of the preceding claims.

5. A method of diagnosing an entity with a plurality of components (c₁, . . . , c_n) which each is assumed to be in a fault-free mode or be in exactly one of at least one fault mode, the method comprising receiving diagnostic expressions (D, E) indicating at least one of said modes for at least one of said components (c₁, . . . , c_n), and generating a status report (R[Q]) based on the diagnostic expressions (D, E), wherein:

receiving a first listing (D) of diagnostic expressions (D₁, . . . , D_n) constituting a first part of said diagnostic expressions,

receiving a second listing (E) of diagnostic expressions (E₁, . . . , E_m) constituting a second part of said diagnostic expressions,

storing the first and second listings (D;

E) in a first storage area (120),

creating an empty listing of enhanced diagnostic expressions (Q) by clearing any contents of a second storage area (130), and thereafter, for each combination of diagnostic expressions (D_i, E_j) in the first and second listings (D;

E),

generating a current joint diagnostic expression (Q_new) as a conjunction of a first diagnostic expression (D_i) from the first listing (D) and a second diagnostic expression (E_j) from the second listing (E),

comparing the current joint diagnostic expression (Q_new) with each diagnostic expression in the listing of enhanced diagnostic expressions (Q) stored in the second storage area (130),

discarding the current joint diagnostic expression (Q_new), if there exists a previous expression (Q_k) in the listing of enhanced diagnostic expressions (Q), and the current joint diagnostic expression (Q_new) implies the previous expression (Q_k),

discarding the current joint diagnostic expression (Q_new), if there exists a first diagnostic expression (D_k) in the first listing (D), the first diagnostic expression (D_k) having not yet been included in a joint diagnostic expression and the current joint diagnostic expression (Q_new) implies the first diagnostic expression (D_k),

discarding the current joint diagnostic expression (Q_new), if there exists a second diagnostic expression (E_k) in the second listing (E), the second diagnostic expression (E_k) having not yet been included in a joint diagnostic expression and the current joint diagnostic expression (Q_new) implies the second diagnostic expression (E_k), otherwise

storing the joint diagnostic expression (Q_new) as an addition to the listing of enhanced diagnostic expressions (Q) in the second storage area (130), and

generating a status report (R[Q]) based on the listing of enhanced diagnostic expressions (Q).

6. The method according to claim 5, wherein at least one of the respective receiving first and second listing steps receives a respective first or second listing (D;

E) that reflects test results from at least one sensor unit associated with at least one of said components (c₁, . . . , c_n).

7. The method according to claim 5, wherein at least one of the respective receiving first and second listing steps receives a respective first or second listing (D;

E) that includes diagnostic expressions generated by at least one auxiliary diagnosis engine adapted to generate status reports with respect to at least a sub-group of said components (c₁, . . . , c_n).

8. A computer program product directly loadable into the internal memory of a computer, comprising software for controlling the steps of claim 5 when said program is run on the computer.

9. A computer program product according to claim 8 further comprising software for controlling the steps of claim 6 when said program is run on the computer.

10. A computer program product according to claim 8 further comprising software for controlling the steps of claim 7 when said program is run on the computer.

11. A computer readable medium (140), having a program recorded thereon, where the program is to make a computer control the steps of claim 5.

12. A computer readable medium according to claim 11, wherein said program recorded thereon is further capable of making a computer control the steps of claim 6.

13. A computer readable medium according to claim 11, wherein said program recorded thereon is further capable of making a computer control the steps of claim 7.