Method and apparatus for isolating root cause of low state of charge of a DC power source

• US 10,054,643 B2
• Filed: 01/06/2017
• Issued: 08/21/2018
• Est. Priority Date: 01/06/2017
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Sankavaram, Chaitanya, Du, Xinyu, Jiang, Shengbing, Zhang, Yilu
• Primary Examiner(s): Huynh, Hai
• Application Number:
  US15/399,947
• Publication Number:
  US 20180196106A1
• Time in Patent Office: 592 Days
• Field of Search: 1231793, 1231792, 701113, 7311459
• CPC Class Codes: F02N 11/0848 with means for detecting successful engine start, e.g. to stop starter actuation
• CPC Class Codes: F02N 11/0862 characterised by the electrical power supply means, e.g. battery
• CPC Class Codes: F02N 11/108 for diagnosis of the starter or its components
• CPC Class Codes: F02N 11/14 Starting of engines by means of electric starters with external current supply F02N11/12 takes precedence
• CPC Class Codes: F02N 2200/061 Battery state of charge [SOC]
• CPC Class Codes: F02N 2200/062 Battery current
• CPC Class Codes: F02N 2200/063 Battery voltage
• CPC Class Codes: F02N 2200/064 Battery temperature
• CPC Class Codes: F02N 2300/304 with other systems inside the vehicle
• CPC Class Codes: F02N 2300/306 with external senders or receivers, e.g. receiving signals from traffic lights, other vehicles or base stations
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G07C 5/008 communicating information to a remotely located station transmission systems for measured values G08C
• CPC Class Codes: G07C 5/0808 Diagnosing performance data testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005

Abstract

A vehicle including an internal combustion engine, a DC power source and a controller are described. The internal combustion engine includes an engine starting system and an electrical charging system. A method for monitoring the DC power source includes determining a State of Charge (SOC) for the DC power source. Upon detecting that the SOC is less than a threshold SOC, routines are executed in the controller to evaluate a plurality of potential root causes associated with the low SOC. At least one of the potential root causes associated with the low SOC may be identified as a candidate root cause, and a fault probability for each of the candidate root causes is determined. One of the candidate root causes is determined to be a final root cause based upon the fault probabilities associated with the candidate root causes.

Claims

1. A method for monitoring a DC power source that is electrically connected to a charging system that is disposed on an internal combustion engine that is disposed on a vehicle, the method comprising:

determining a State of Charge (SOC) for the DC power source; and

upon detecting that the SOC is less than a threshold SOC that is associated with starting the internal combustion engine;

evaluating, via a controller, states associated with a plurality of potential root causes related to the SOC being less than the threshold SOC,

determining that at least one of the potential root causes is a candidate root cause based upon the states,

determining a fault probability for each candidate root cause, and

determining that one of the candidate root causes is a final root cause based upon the fault probabilities associated with each of the candidate root causes; and

communicating, via a service connector, the final root cause from the controller to an off-board device.

2. The method of claim 1, wherein determining a fault probability for each candidate root cause comprises determining a probability of occurrence for each candidate root cause and determining a probability of fault for each candidate root cause.

3. The method of claim 1, wherein determining that one of the candidate root causes is a final root cause based upon the fault probabilities associated with the candidate root causes comprises selecting the one of the candidate root causes having the greatest fault probability as the final root cause.

4. The method of claim 1, wherein evaluating a plurality of potential root causes associated with the low SOC comprises evaluating a state of health of the DC power source.

5. The method of claim 1, wherein evaluating a plurality of potential root causes associated with the low SOC comprises evaluating performance of a charging system disposed to supply electric power to charge the DC power source.

6. The method of claim 1, wherein evaluating a plurality of potential root causes associated with the low SOC comprises evaluating a wake-up current associated with the DC power source.

7. The method of claim 1, wherein evaluating a plurality of potential root causes associated with the low SOC comprises evaluating engine operation and vehicle usage related to charging of the DC power source.

8. The method of claim 1, wherein evaluating a plurality of potential root causes associated with the low SOC comprises evaluating engine starting events.

9. The method of claim 1, wherein evaluating a plurality of potential root causes associated with the low SOC comprises evaluating on-board devices that are disposed to monitor the DC power source.

10. The method of claim 9, wherein evaluating on-board devices that are disposed to monitor the DC power source comprises evaluating a current sensor, a voltage sensor and a temperature sensor.

11. The method of claim 1, wherein determining the SOC for the DC power source comprises monitoring current flow into and out of the DC power source.

12. An internal combustion engine of a vehicle, comprising:

a starting system that is electrically connected to a DC power source that is electrically connected to a charging system;

an electrical charging system electrically connected to the DC power source;

a service connector; and

a controller, in communication with the internal combustion engine, the starting system, the electrical charging system, the service connector, and the DC power source, the controller including an instruction set, the instruction set executable to;

determine a State of Charge (SOC) for the DC power source, and determine that the SOC is less than a threshold SOC,

evaluate states associated with a plurality of potential root causes associated with the SOC being less than the threshold SOC,

determine that at least one of the potential root causes is a candidate root cause based upon the evaluated states,

determine a fault probability for each of the candidate root causes,

determine that one of the candidate root causes is a final root cause based upon the fault probabilities associated with the candidate root causes, and

communicate, via the service connector, the final root cause from the controller to an off-board device.

13. A service controller for a vehicle that includes an internal combustion engine, a starting system, a DC power source, an electrical charging system, comprising:

the service controller being in communication with a service connector and in communication with the internal combustion engine, the starting system, the electrical charging system and the DC power source, the controller including an instruction set, the instruction set executable to;

determine a State of Charge (SOC) for the DC power source, and determine that the SOC is less than a threshold SOC,

evaluate states associated with a plurality of potential root causes associated with the SOC being less than the threshold SOC,

determine that at least one of the potential root causes is a candidate root cause based upon the evaluated states,

determine a fault probability for each of the candidate root causes,

determine that one of the candidate root causes is a final root cause based upon the fault probabilities associated with the candidate root causes; and

communicate, via the service connector, the final root cause from the controller to an off-board device.

14. The service controller of claim 13, wherein the service connector is disposed to communicate the final root cause from the controller to an off-board service tool.

15. The service controller of claim 14, wherein the service connector includes a mechanical linkage and a communication link to the off-board service tool.

16. The service controller of claim 14, wherein the service connector includes a wireless communication link to the off-board service tool.

17. The service controller of claim 14, wherein the service connector includes a telematics module disposed to communicate to the off-board service tool.

18. The service controller of claim 14, wherein the off-board service tool is remotely located from the vehicle.