Electronic control system with self-diagnostic function for use in motor vehicle

• US 5,276,619 A
• Filed: 04/05/1991
• Issued: 01/04/1994
• Est. Priority Date: 04/06/1990
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Kojima, Naoyuki, Ohara, Kouichi
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US07/680,891
• Time in Patent Office: 1,005 Days
• Field of Search: 364/424.03, 364/424.04, 364/424.01, 364/431.11, 364/431.12, 371/53, 123/479
• US Class Current: 701/35
• 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 41/2416 Interpolation techniques
• CPC Class Codes: F02D 41/2422 Selective use of one or more tables
• CPC Class Codes: F02D 41/249 Methods for preventing the loss of data
• CPC Class Codes: G01M 15/05 by combined monitoring of two or more different engine parameters
• CPC Class Codes: G05B 9/02 electric
• CPC Class Codes: G07C 5/0808 Diagnosing performance data testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005

Abstract

An electronic control system with a self-diagnostic function for use in a motor vehicle, which is arranged to write the vehicle operation state data such as engine intake air amount at the time of no occurrence of abnormality into the internal memory of a microcomputer basically making up an electronic control system and, in response to the occurrence of abnormality, add check-function data to the operation state data which is in turn transferred to a backup memory. That is, at the time when abnormality occurs, the data whose significance is relatively high are stored in an internal storage of a microcomputer such as a non-volatile battery-backup RAM with check-function data being respectively added thereto so as to improve the data reliability. On the other hand, the data whose significance is relatively low are stored in an external storage such as a battery-backup RAM, together with check-function data for totally checking the data, thereby improving the data reliability. In addition, the storing of the data into two kinds of storages allows improvement of the storage capacity.

Claims

1. An electronic control system for use in a motor vehicle which performs self-diagnostics by storing data indicative of an operation condition at a time when an abnormality occurs, comprising:

sensor means for sensing an operating condition of a motor vehicle and generating data indicative of said sensed operating condition, said data being categorized as either having high significance or low significance;

processing means for detecting an occurrence of an abnormality by analyzing data indicative of said operating condition, said processing means including a central processing unit and a write-allowable internal storage means for storing data indicative of said operating condition;

write-allowable external storage means for storing data indicative of said operating condition, said external storage means being located outside of said processing means;

writing means for writing data to said storage means, wherein a high significance data is written to said internal storage means and low significance data is written to said external storage means;

outputting means for outputting the data stored in said internal storage means and external storage means in response to a signal inputted from an external circuit.

2. An electronic control system as claimed in claim 1, wherein said processing means adds inversion data to said operating condition data categorized as having high significance, said inversion data and operating condition data being written to said write-allowable internal storage means.

3. An electronic control system as claimed in claim 1, wherein said internal storage means comprises a first RAM non-backed up by a battery and a second RAM backed up by said battery, said processing means being equipped with means for storing said operating condition data into said first RAM at a time when an abnormality does not occur and further equipped with means for transferring the high significance data from said first RAM to said second RAM and transferring the low significance data from said first RAM to said external storage means when an abnormality does occur.

4. An electronic control system as claim in claim 1, wherein said outputting means includes means for discriminating an abnormality code to be inputted from said external circuit, means for reading out the operating condition data corresponding to the discriminated abnormality code, means for comparing there ad-out data with predetermined data so as to check the abnormality of the data, means for supplying an error code to an external device in response to occurrence of the abnormality, and means for supplying the data to an external device in response to no occurrence of the abnormality.

5. An electronic control system for use in a motor vehicle which performs self-diagnostics in terms of abnormalities, comprising:

an intake air amount sensor for sensing an intake air amount into an engine of said motor vehicle and generating a detection signal indicative of the sensed intake air amount;

an engine speed sensor for sensing an engine speed and generating a detection signal indicative of the sensed engine speed;

a cooling water temperature sensor for sensing a temperature of a cooling water of said engine and generating a detection signal indicative of the sensed cooling water temperature;

a processing unit, responsive to said detection signals from said sensors, for processing data corresponding to said detection signals, said processing unit being equipped with a microprocessor, a first write-allowable internal memory and a second write-allowable internal memory;

a write-allowable external memory backed up by a battery and provided at an outside of said processing unit so as to be electrically coupled to said processing unit; and

wherein said processing unit is equipped with means for storing a plurality of data corresponding to all of said detection signals into said first internal memory at a time when an abnormality does not occur, means for transferring data corresponding to the sensed intake air amount and data corresponding to the sensed engine speed from said first internal memory to said second internal memory and transferring data corresponding to the sensed cooling water temperature from said first internal memory to said external memory when an abnormality occurs, and means for outputting the data stored in said second internal memory and external memory in response to a signal inputted from an external circuit.

6. An electronic control system for use in a motor vehicle, comprising:

a first sensor for sensing a first operation state and generating a first detection signal indicative of the sensed first operation state;

a second sensor for sensing a second operation state and generating a second detection signal indicative of the sensed second operation state, said second detection signal categorized as having a lower significance than said first detection signal;

a third sensor for sensing a third operation state and generating a third detection signal indicative of the sensed third operation state, said third detection signal categorized as having a lower significance than said first detection signal;

a processing unit, responsive to all of the detection signals from said first to third sensors, for processing data corresponding to all of the detection signals, said processing unit being equipped with a microprocessor, a first write-allowable internal memory and a second write-allowable internal memory backed up by a battery;

a write-allowable external memory backed up by said battery and provided outside of said processing unit so as to electrically coupled to said processing unit;

wherein said processing unit is equipped with means for storing a plurality of data corresponding to all the detection signals into said first internal memory at a time when an abnormality does not occur, and further equipped with means for adding first check-function data to said data corresponding to the detection signal of said first sensor and transferring them from said first internal memory to said second internal memory when an abnormality occurs, means for adding second check-function data to said data corresponding to the detection signals of said second and third sensors and transferring them from said first internal memory to said external memory when an abnormality occurs, said second check-function data being constructed by taking the sum of said second and third sensor data, and means for outputting said data stored in said second internal memory and external memory in response to a signal inputted from an external circuit.

7. An electronic control system for use in a motor vehicle, comprising:

sensor means for sensing an operation state of said motor vehicle and generating a detection signal indicative of the detected operation state;

a processing unit responsive to the generated detection signal to process data corresponding to the detection signal, said processing unit equipped with a microprocessor and a write-allowable internal memory;

a write-allowable backup memory electrically coupled to said processing unit;

wherein said processing unit has means for storing a plurality of data corresponding to said detection signal into said memory when an abnormality does not occur, means for adding check-function data to the data stored in said internal memory, means for transferring said data from said internal memory to said backup memory when the abnormality occurs, and means for outputting any data in said internal memory and external memory in response to a signal inputted from an external circuit.