Memory check apparatus and method for checking data upon retrieval from memory

• US 6,216,084 B1
• Filed: 07/29/1999
• Issued: 04/10/2001
• Est. Priority Date: 10/08/1998
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Iwai, Akihito, Uematsu, Yoshitaka, Nomura, Hajime
• Primary Examiner(s): WOLFE JR, WILLIS RAY
• Application Number:
  US09/363,414
• Time in Patent Office: 621 Days
• Field of Search: 701/101, 701/114, 701/115
• US Class Current: 701/114
• CPC Class Codes: F02D 41/2454 Learning of the air-fuel ratio control
• CPC Class Codes: F02D 41/249 Methods for preventing the loss of data
• CPC Class Codes: F02D 41/2493 Resetting of data to a predefined set of values

Abstract

In a control apparatus and method for vehicles, control data such as engine air-fuel ratio correction values are learned and stored in a backup RAM to be used in engine control. Before the data are actually used in the engine control, not all the stored data are checked but only the data read out from the backup RAM to be used for control calculation are checked. Thus, all the memory data necessary are ensured to be checked in a short period of time, and improper control operation resulting from erroneous data can be obviated. Further, abnormality checking of all the stored data is executed at a specified timing separately. When the abnormality is found in any of the data, all the data in the backup RAM are initialized.

Claims

1. A memory check apparatus for checking abnormality of data stored in a memory to be used in control value calculations for a vehicle, the apparatus comprising:

an execution order determination unit for determining an order of execution of a plurality of tasks which execute control value calculation programs;

an engine control module including the plurality of tasks; and

a memory retrieval module including a processing of retrieving the data from the memory, the memory retrieval module being for checking abnormality of only the retrieved data before being used in the control value calculation programs and setting the retrieved data to an initialized value to be used in the control value calculation programs in place of the retrieved data.

2. A memory check apparatus for checking abnormality of data stored in a memory to be used in control value calculations for a vehicle, the apparatus comprising:

an execution order determination unit for determining an order of execution of a plurality of tasks which execute control value calculation programs;

an engine control module including the plurality of tasks;

a memory retrieval module including a processing of retrieving the data from the memory, the memory retrieval module being for checking abnormality of only the retrieved data before being used in the control value calculation programs and setting the retrieved data to an initialized value to be used in the control value calculation programs in place of the retrieved data; and

a memory initialization module for executing an abnormality checking program at a timing different from execution of the processing for checking abnormality and for initializing all the stored data in the memory upon detection of abnormality in any one of the retrieved data.

3. A memory check method for checking abnormality of data stored in a memory to be used in control value calculations for a vehicle, the method comprising the steps of:

retrieving from the memory only data which is required to be used in the control value calculations;

checking abnormality of the retrieved data before using in the control value calculations;

setting the retrieved data to an initialized value to be used in the control value calculation programs in place of the retrieved data, when the retrieved data is found abnormal by the checking step; and

maintaining all the data in the memory unchanged at the time of the setting step.

4. A memory check apparatus for checking abnormality of data stored in a memory to be used in control value calculations for a vehicle, the apparatus comprising:

an execution order determination unit for determining an order of execution of a plurality of tasks which execute control value calculation programs;

an engine control module including the plurality of tasks;

a backup RAM retrieval module including a processing of retrieving the data from the backup RAM;

a backup RAM initialization module including an abnormality checking processing for executing an abnormality checking program and for initializing all the stored data in the backup RAM upon detection of abnormality in any one of the retrieved data,

wherein the execution order determination module is for determining execution timings of the plurality of tasks, initiating predetermined execution tasks in the engine control module at the determined timing, and initiating the abnormality checking processing at a timing different from the determined timings,

the predetermined execution tasks are for executing the control value calculation program when called from the execution order determination unit and initiating the data retrieving processing of the backup RAM retrieval module,

the data retrieving processing is for retrieving the data stored in the backup RAM, executing the abnormality checking program to check the retrieved data, and setting an abnormality information when the retrieved data is abnormal, and

the abnormality checking processing is for checking the abnormality information, and initializing all the stored data in the backup RAM when abnormality is found in any one of the execution tasks.

5. A memory check method for checking abnormality of data stored in a memory to be used in control value calculations for a vehicle, the method comprising the steps of:

retrieving from the memory only data which is required to be used in the control value calculations;

checking abnormality of the retrieved data before using in the control value calculations;

setting abnormality information when the abnormality is found by the checking step;

checking the abnormality information at a specified timing different from a sequence of the retrieving step, the abnormality checking step and the setting step; and

initializing all the stored data in the memory upon detection of the abnormality information in any one of the retrieved data.

6. A memory check method as in claim 5, further comprising the step of:

setting the retrieved data to an initialized value to be used in the control value calculation programs in place of the retrieved data, when the retrieved data is found abnormal by the checking step.

7. A memory check method for a vehicle having a control object and a computer including a memory storing therein various data to be used in calculating a control value for the control object, the method comprising the steps of:

retrieving a part of the various data from the memory when requested for calculating the control value;

checking only the retrieved part of data before being used in calculating the control value; and

disabling a use of the retrieved part of data in calculating the control value when the retrieved part of the data is determined abnormal by the checking step.

8. A memory check method as in claim 7, further comprising the steps of:

setting the retrieved part of data to an initial value; and

calculating the control value by using the initial value in place of the retrieved part of data.

9. A memory check method as in claim 7, further comprising the step of:

setting all the various data in the memory to an initial value at a predetermined time different from the checking step and the disabling step.

10. A memory check method as in claim 7, wherein:

the various data are variable type which are updated from time to time; and

the control object is an engine of the vehicle.