ELECTRONIC CONTROL UNIT

• US 20090037046A1
• Filed: 08/04/2008
• Published: 02/05/2009
• Est. Priority Date: 08/03/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Teramura, Mikio
• Granted Patent: US 8,190,321 B2
• Time in Patent Office: Days
• US Class Current: 701/35
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 2050/146 Display means
• CPC Class Codes: B60W 50/02 Ensuring safety in case of control system failures, e.g. by diagnosing, circumventing or fixing failures
• CPC Class Codes: B60W 50/04 Monitoring the functioning of the control system
• 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 41/2487 Methods for rewriting
• CPC Class Codes: G07C 3/005 during manufacturing process
• CPC Class Codes: G07C 5/0808 Diagnosing performance data testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005
• CPC Class Codes: G07C 5/085 using electronic data carriers

Abstract

An electronic control unit installed in a vehicle performs diagnosis of plural diagnosis objects based on sensor signals and the like, and stores diagnosis results that indicate abnormality of the diagnosis objects in a DTC storage area only when the DTC storage area does not store data having an initial value. The data in the DTC storage area is, in other words, rewritten to different values from the initial value for allowing storage of DTC when the electronic control unit determines that all of the diagnosis objects are in a normal condition with no indication of abnormality after performing diagnosis, thereby making it possible to exclusively preventing useless abnormality information detected during a vehicle manufacturing process from being stored in an rewritable non-volatile memory.

Claims

1. An electronic control unit installed in a vehicle, the electronic control unit comprising:

a non-volatile memory capable of re-writing data stored therein;

a diagnosis unit capable of checking if failure is occurred in a device installed in the vehicle based on information therefrom and storing abnormality data in the non-volatile memory after determining abnormality has occurred in the device installed in the vehicle;

a permission information storage capable of storing permission information indicating whether or not storage of the abnormality information in the non-volatile memory is permitted;

a permission switching unit capable of switching the permission information from non-permission of the storage of the abnormality information to permission of the storage of the abnormality information after the diagnosis unit has determined that the device installed in the vehicle is in a normal condition with no indication of abnormality; and

a storage permission unit capable of permitting the diagnosis unit to store the abnormality information in the non-volatile memory when the permission information stored in the permission information storage indicates permission of the storage of the abnormality information in the non-volatile memory.

2. The electronic control unit according to claim 1 further comprising:

a standby RAM to which electric power is continuously supplied for storing data,

wherein the diagnosing means is configured to be continuously permitted to store the diagnosis result in the standby RAM.

3. The electronic control unit according to claim 1, wherein

the permission information storage is a predetermined memory area in the non-volatile memory.

4. The electronic control unit according to claim 3, wherein

the predetermined memory area is one of a part of the memory area for storing the abnormality data and a whole of the memory area for storing the abnormality data in the non-volatile memory,

the permission switching unit re-writes data in the predetermined memory area from an initial value that is set prior to installation of the electronic control unit in the vehicle to a specific value that is different from the abnormality data upon determining that the device installed in the vehicle is in the normal condition,

data having the initial value in the predetermined memory area indicates non-permission of the storage of the abnormality information, and

data not having the initial value in the predetermined memory area indicates permission of the storage of the abnormality information

5. The electronic control unit according to claim 1 further comprising:

a response unit configured to transmit a response signal in response to a request signal to an external device when the request signal transmitted from the external device is received on a condition that the permission information indicates permission of the storage of the abnormality information

6. The electronic control unit of claim 5, wherein

the request signal requests data in the memory area that is used to store the abnormality information in the non-volatile memory, and

the response unit transmits data in the memory area that is used to store the abnormality information to the external device.

7. An electronic control unit installed in a vehicle, the electronic control unit comprising:

a non-volatile memory capable of re-writing data stored therein, and

a diagnosis unit capable of storing abnormality data in the non-volatile memory after determining abnormality based on information from a device installed in the vehicle, wherein

diagnosis of the device installed in the vehicle is performed prior to shipment of the vehicle, and

when the diagnosis of the device by the diagnosis unit determines that the device installed in the vehicle is in a normal condition with no indication of abnormality, storage of result of the diagnosis in the non-volatile memory is permitted.

8. An electronic control unit installed in a vehicle, the electronic control unit comprising:

a non-volatile memory capable of re-writing data stored therein, the non-volatile memory; and

a diagnosis unit capable of storing abnormality data in the non-volatile memory after determining abnormality based on information from a device installed in the vehicle, wherein

the non-volatile memory has an initial value stored in all of memory areas in a pre-installation condition in the vehicle,

when change of the initial value is detected in a period after installation of the electronic control unit in the vehicle and before shipment of the vehicle, storage of a result of diagnosis by the diagnosis unit in the non-volatile memory is permitted.