Electronic control system

• US 20040080997A1
• Filed: 10/06/2003
• Published: 04/29/2004
• Est. Priority Date: 10/25/2002
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Okada, Kazunori, Hozuka, Minoru
• Granted Patent: US 6,957,135 B2
• Time in Patent Office: Days
• US Class Current: 365/200
• CPC Class Codes: G11C 16/102 External programming circuits, e.g. EPROM programmers; In-circuit programming or reprogramming; EPROM emulators
• CPC Class Codes: G11C 16/105 Circuits or methods for updating contents of nonvolatile memory, especially with 'security' features to ensure reliable replacement, i.e. preventing that old data is lost before new data is reliably written
• CPC Class Codes: G11C 7/24 Memory cell safety or protection circuits, e.g. arrangements for preventing inadvertent reading or writing; Status cells; Test cells

Abstract

An engine control system stores data indicating a monitor frequency ratio for each failure diagnosis target item in EEPROM and standby RAM being backed up by a battery. The failure diagnosis target items are designated based on Rate Base Monitor Method. A data item of the data indicating a monitor frequency is incremented by one, at one time at the maximum, for one operation period of the system. When the system starts its operation, whether a value S [i] in standby RAM is greater by one than a value E [i] in EEPROM is determined for each data item. When the determination is affirmed for a given data item, it is determined that storing of the given data item is not completed in EEPROM for the preceding operation period. The value S [i] is thereby written in EEPROM.

Claims

1. An electronic control system that enters an operation period from turning on of operating electric power to turning off of the operating electric power and makes both a non-volatile memory and a standby RAM execute storing of continuous storing target data, wherein in the non-volatile memory data is electrically erasable, wherein the standby RAM is a memory and is continuously supplied with data-storing electric power for continuously storing data, and wherein the continuous storing target data needs to be continuously stored even while the operating electric power is turned off and has a value that is updated as advancing to a given change direction with at least one of increasing and decreasing based on given regularity, the electronic control system comprising:

determining means for executing, when a given operation period is started due to turning on of the operating electric power, a determination of whether a value of the continuous storing target data in the standby RAM advances to the given change direction further than a value of the continuous storing target data in the non-volatile memory; and

detecting means for detecting, when the determination executed by the determining means is affirmed, that storing of the continuous storing target data in the non-volatile memory is not completed for a former operation period preceding to the given operation period.

2. The electronic control system according to claim 1,

wherein the continuous storing target data has a value that is updated, at most one time, for an operation period from turning on of the operating electric power to turning off of the operating electric power, as advancing to the given change direction by a given integral number,

wherein the determining means executes, when the given operation period is started due to turning on of the operating electric power, a given determination of whether a value of the continuous storing target data in the standby RAM advances to the given change direction by the given integral number than a value of the continuous storing target data in the non-volatile memory, and

wherein the detecting means detects, when the given determination is affirmed, that storing of the continuous storing target data in the non-volatile memory is not completed for the former operation period preceding to the given operation period.

3. The electronic control system according to claim 1, further comprising:

recovering means for writing in the non-volatile memory the value of the continuous storing target data in the standby RAM when the detecting means detects that storing of the continuous storing target data in the non-volatile memory is not completed for the former operation period.

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

prohibiting means for executing, when the given operation period is started, a certain determination of whether the continuous storing target data in the standby RAM is normal, and for prohibiting, when the certain determination is negated, the detecting means from detecting that storing of the continuous storing target data in the non-volatile memory is not completed for the former operation period even when the given determination is affirmed.

5. An electronic control system that enters an operation period from turning on of operating electric power to turning off of the operating electric power and controls an in-vehicle device in a vehicle, the electronic control system comprising:

state detecting means for detecting that the vehicle enters a given operating state;

failure diagnosing means for executing a failure diagnosis on the in-vehicle device when a given condition is effected;

a non-volatile memory where stored data is electrically erasable;

a standby RAM that is continuously supplied with data-storing electric power for continuously storing data and stores frequency information including an operation frequency and a failure diagnosis frequency;

rewriting means for rewriting the frequency information in the standby RAM for the operation period, wherein the operation frequency of the frequency information is rewritten as being incremented by one when the state detecting means detects that the vehicle enters the given operating state while the failure diagnosis frequency of the frequency information is rewritten as being incremented by one when the failure diagnosing means executes the failure diagnosis;

storing means for storing, after the rewriting means rewrites the frequency information, the rewritten frequency information in the non-volatile memory;

determining means for executing, when a given operation period is started due to turning on of the operating electric power, a determination of whether at least one frequency of the operation frequency and the failure diagnosis frequency in the standby RAM has a value greater by one than a value of the one frequency of the operation frequency and the failure diagnosis frequency in the non-volatile memory; and

mis-storing detecting means for detecting, when the determination executed by the determining means is affirmed, that storing of the one frequency of the operation frequency and the failure diagnosis frequency in the non-volatile memory is not completed for a former operation period preceding to the given operation period.

6. The electronic control system according to claim 5, further comprising:

outputting means that is connectable with a diagnosing tool outside of the vehicle and is for outputting to the diagnosing tool the frequency information stored in the non-volatile memory when outputting of the frequency information is requested from the diagnosing tool.