Electronic control unit and computer program

Patent metadata

Field	Value
Publication number	US-9797362-B2
Application number	US-201615149473-A
Country	US
Kind code	B2
Filing date	May 9, 2016
Priority date	Aug 28, 2015
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A starter control apparatus outputs a conduction command to a starter relay when an engine start request is generated and starts driving of a starter. After the engine is started, when a condition for executing the failure diagnosis processing is satisfied, the starter control apparatus outputs a non-conduction command to a starter cutoff relay and diagnoses the starter cutoff relay for failure. The starter control apparatus determines that the starter cutoff relay is normal when a voltage applied to the starter after notification of the non-conduction command to the starter cutoff relay does not exceed a predetermined voltage. The starter control apparatus determines that the starter cutoff relay is abnormal when the voltage applied to the starter exceeds the predetermined voltage.

First claim

What is claimed is:

1. An electronic control unit for a vehicle, which includes a first switch part and a second switch part connected in series between an electric load for starting an engine of the vehicle and a power supply battery, the first switch part being for driving the electric load and the second switch part being for a fail-safe operation, the electronic control unit comprising:
a switch control part for outputting a conduction command and a non-conduction command to the first switch part and the second switch part of and controlling the first switch part and the second switch part to be conductive and anon-conductive, respectively;
a physical quantity detection part for detecting a physical quantity, which electrically affects on the electric load; and
a determination part for determining whether the second switch part is normal or abnormal based on a detection result of the physical quantity detection part,
wherein, as failure diagnosis by a first diagnosis method,
the switch control part outputs the conduction command to the first switch part upon determination of generation of an engine start request thereby to start driving of the electric load while rendering the second switch part to be conductive, and, after the engine is started, outputting the non-conduction command to the second switch part while rendering the first switch part to be conductive upon determination of satisfaction of condition for executing the failure diagnosis according to the first diagnosis method, and
the determination part determines, in the failure diagnosis according to the first diagnosis method, that the second switch part is normal when the physical quantity detected after the non-conduction command is outputted to the second switch part fails to exceed a predetermined value, and that the second switch part is abnormal when the physical quantity exceeds the predetermined value.

2. The electronic control unit according to claim 1 , wherein:
the switch control part outputs the non-conduction command to the first switch part after the second switch part is determined to be normal or abnormal by the determination part.

3. The electronic control unit according to claim 1 , wherein:
the switch control part determines that the condition for executing the failure diagnosis according to the first diagnosis method is satisfied after each starting of the engine.

4. The electronic control unit according to claim 1 , wherein:
the switch control part determines that the condition for executing the failure diagnosis according to the first diagnosis method is satisfied after one of plural starting of the engine.

5. The electronic control unit according to claim 1 , wherein:
the switch control part determines that the condition for executing the failure diagnosis according to the first diagnosis method is satisfied after starting of the engine, which follows a predetermined travel distance or a predetermined travel time elapse of the vehicle measured after previous determination that the condition for executing the failure diagnosis according to the first diagnosis method is satisfied.

6. The electronic control unit according to claim 1 , wherein, as failure diagnosis according to a second diagnosis method:
the switch control part outputs the conduction command to the first switch part upon determination of the generation of the engine start request while rendering the second switch part to be non-conductive; and
the determination part determines, in the failure diagnosis according to the second diagnosis method, that the second switch part is normal when the physical quantity detected after the conduction command is outputted to the first switch part fails to exceed the predetermined value, and that the second switch part is abnormal when the physical quantity exceeds the predetermined value.

7. The electronic control unit according to claim 6 , wherein:
the switch control part executes the failure diagnosis according to the second diagnosis method, when at least one of numbers of determinations of the determination part that the second switch part is abnormal or normal.

8. The electronic control unit according to claim 6 , wherein:
the switch control part determines that the condition for executing the failure diagnosis according to the second diagnosis method is satisfied after each generation of the engine start request.

9. The electronic control unit according to claim 6 , wherein:
the switch control part determines that the condition for executing the failure diagnosis according to the second diagnosis method is satisfied after one of plural engine start requests.

10. The electronic control unit according to claim 6 , wherein:
the switch control part determines that the condition for executing the failure diagnosis according to the second diagnosis method is satisfied after generation of the engine start request, which follows a predetermined travel distance or a predetermined travel time elapse of the vehicle measured after previous determination that the condition for executing the failure diagnosis according to the second method is satisfied.

11. The electronic control unit according to claim 1 , wherein:
the physical quantity detection part includes a voltage detection part for detecting a voltage applied to the electric load; and
the determination part determines that the second switch part is normal when the voltage fails to exceed a predetermined voltage and that the second switch part is abnormal when the voltage exceeds the predetermined voltage.

12. A computer program for a microcomputer of an electronic control unit for a vehicle, which includes a first switch part and a second switch part connected in series between an electric load for starting an engine of the vehicle and a power supply battery, the first switch part being for driving the electric load and the second switch part being for a fail-safe operation, the computer program comprising:
a first process for checking whether an engine start request is generated as failure diagnosis by a first diagnosis method;
a second process for outputting, upon determination that the engine start request is generated, a conduction command to the first switch part thereby to start driving of the electric load while rendering the second switch part to be conductive;
a third process for checking, after engine starting, whether a condition for executing the failure diagnosis according to the first diagnosis method is satisfied;
a fourth process for outputting, upon determination of the third process that the condition for executing the failure diagnosis according to the first diagnosis method is satisfied, a non-conduction command to the second switch part while rendering the first switch part to be conductive; and
a fifth process for determining that the second switch part is normal when a physical quantity, which affects on the electric load and is detected after the non-conduction command is outputted to the second switch part by the fourth process, fails to exceed a predetermined value, and that the second switch part is abnormal when the physical quantity exceeds the predetermined value.

13. The computer program according to claim 12 , further comprising:
as failure diagnosis by a second diagnosis method, a sixth process for checking whether a condition for executing failure diagnosis by a second diagnosis method is satisfied after generation of an engine start request;
a seventh process for outputting, upon determination of the sixth process that the condition for executing the failure diagnosis according to the second diagnosis method is satisfied, a conduction command to the first s

Assignees

• Denso Corp

Inventors

• Nagata Kouji

Classifications

• F02N2200/043

  Starter voltage · CPC title

• F02N11/108 Primary

  for diagnosis of the starter or its components · CPC title

• F02N11/087

  Details of the switching means in starting circuits, e.g. relays or electronic switches · CPC title

• F02N11/0862

  characterised by the electrical power supply means, e.g. battery · CPC title