Electronic control unit with permission switching

• US 8,190,321 B2
• Filed: 08/04/2008
• Issued: 05/29/2012
• Est. Priority Date: 08/03/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Teramura, Mikio
• Primary Examiner(s): Jayne, Darnell
• Assistant Examiner(s): Varghese, Sasha T
• Application Number:
  US12/185,274
• Publication Number:
  US 20090037046A1
• Time in Patent Office: 1,394 Days
• Field of Search: 701/29.1, 701/33.4, 701/30.1, 701/29.7, 701/31.7, 701/32.2, 702/187
• US Class Current: 701/30.1
• 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 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 DTCs 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 prevent 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;

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

a diagnosis unit capable of checking if a failure has occurred in a device installed in the vehicle based on information from the device and storing abnormality data in the non-volatile memory after determining that an 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 data 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 data to permission of the storage of the abnormality data 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 data in at least one of the non-volatile memory and the standby RAM,

wherein when the diagnosis unit detects an abnormality in the device and the permission information storage permits the storage of the abnormality data in the non-volatile memory, the storage permission unit stores the abnormality data in the non-volatile memory and the standby RAM, and

wherein when the diagnosis unit detects an abnormality in the device and the permission information storage does not permit the storage of the abnormality data in the non-volatile memory, the storage permission unit stores the abnormality data in the standby RAM.

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

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

3. The electronic control unit according to claim 2, wherein

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 data, and

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

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

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

5. The electronic control unit of claim 4, wherein

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

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

6. The electronic control unit of claim 1, wherein

the device includes a plurality of sub-devices,

wherein when a second sub-device is dependent upon a first sub-device, such that when the first sub-device is determined to be in a normal condition, the second sub-device can never be determined to be in an abnormal condition, the diagnosis unit omits the second sub-device from a diagnosis process when the first sub-device is determined to be in normal condition.

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

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

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

a diagnosis unit capable of storing abnormality data in at least one of the non-volatile memory and the standby RAM after determining that an abnormality has occurred based on information from a device installed in the vehicle, the diagnosis unit determining the abnormality prior to shipment of the vehicle,

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

wherein when the diagnosis unit determines that the device installed in the vehicle is in an abnormal condition, storage of the result of the diagnosis is permitted in the standby RAM.

8. The electronic control unit of claim 7, wherein

the device includes a plurality of sub-devices,

wherein when a second sub-device is dependent upon a first sub-device, such that when the first sub-device is determined to be in a normal condition, the second sub-device can never be determined to be in an abnormal condition, the diagnosis unit omits the second sub-device from a diagnosis process when the first sub-device is determined to be in normal condition.

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

a non-volatile memory capable of re-writing data, wherein the non-volatile memory has an initial value stored in the non-volatile memory before the ECU is installed in the vehicle,

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

a diagnosis unit capable of storing abnormality data in at least one of the non-volatile memory and the standby RAM after determining abnormality based on information from a device installed in the vehicle,

wherein when the initial value is stored in the non-volatile memory, storage of a result of diagnosis by the diagnosis unit is permitted in the standby RAM and is not permitted in the non-volatile memory;

wherein 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 the result of diagnosis by the diagnosis unit is permitted in the non-volatile memory and in the standby RAM.

10. The electronic control unit of claim 9, wherein

the device includes a plurality of sub-devices,

wherein when a second sub-device is dependent upon a first sub-device, such that when the first sub-device is determined to be in a normal condition, the second sub-device can never be determined to be in an abnormal condition, the diagnosis unit omits the second sub-device from a diagnosis process when the first sub-device is determined to be in normal condition.