Vehicle control system

• US 6,243,630 B1
• Filed: 02/09/1998
• Issued: 06/05/2001
• Est. Priority Date: 03/17/1997
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yamamoto, Yuko, Nakai, Kazuhiko, Oohara, Kouichi, Oguro, Hirokazu, Takaba, Katsumi
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Application Number:
  US09/020,421
• Time in Patent Office: 1,212 Days
• Field of Search: 701/29, 701/35, 701/114
• US Class Current: 701/35
• CPC Class Codes: F02D 2200/501 Vehicle speed
• 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
• CPC Class Codes: G05B 19/0426 Programming the control sequence
• CPC Class Codes: G05B 2219/23325 Transfer modified data from ram to eprom, flash after system have run several cycles
• CPC Class Codes: G05B 2219/23345 Memory is eeprom

Abstract

A vehicle control system reduces the number of times learned value data is written into an electrically rewritable non-volatile ROM (EEPROM),. Learned value data (attained through learning control operation of a vehicle) is saved into the EEPROM, and then on battery disconnection, it can be transferred from the EEPROM back to an ordinary RAM instead of being lost. Each time engine rotating speed NE reaches a predetermined value (e.g., 500 rpm) after the ignition switch is turned on, a counter is incremented. When the counter reaches a predetermined count (e.g., the learned value data as of that time is written into the EEPROM for safe keeping and the counter is reset. Consequently, learned value data is written into the EEPROM in a manner which requires the vehicle to actually run a number of times, thereby making it possible to safely reduce the number of times the learned value data is written into the EEPROM for safe keeping.

Claims

1. A method of controlling operation of a motor vehicle, comprising the steps of:

(a) collecting vehicle operational data if the vehicle has entered a run mode;

(b) temporarily storing the vehicle operational data along with vehicle operational data collected during previous run modes; and

(c) permanently storing temporarily stored vehicle operational data after a predetermined number of run modes if motor vehicle speed is above a predetermined motor vehicle speed threshold.

2. The method of claim 1, further comprising the steps of:

repeating steps (a)-(c); and

replacing earlier permanently stored vehicle operational data with new operational data after a subsequent predetermined number of run modes.

3. The method of claim 1, further comprising the step of:

monitoring a battery of the motor vehicle to determine a battery disconnect status thereof; and

providing system control parameters corresponding to the battery disconnect status.

4. The method of claim 1, wherein said vehicle operational data is learned data that is learned during the run mode.

5. The method of claim 1, wherein said predetermined threshold is larger than 0 km/h.

6. A vehicle control system equipped with an electrically rewritable nonvolatile ROM and arranged so that learned value data attained through learning control operation of a vehicle is written into said novolatile ROM under a predetermined condition and retained therein, said system comprising:

a drive detector that checks whether said vehicle is actually running after an ignition switch thereof is turned on,

a counter that calculates a number of detections made by said drive detector in case of actual drive of said vehicle,

a drive count checker for determining whether a count value indicated by said counter reaches a predetermined value,

wherein, if said drive count checker determines that a count value indicated by said counter is said predetermined value or more, said learned value data is written into said nonvolatile ROM and said count value indicated by said counter is initialized; and

a travel state detector for checking whether or not said vehicle is running at a vehicle travel speed higher than or equal to a predetermined travel speed level,

wherein, if said drive count checker determines that a count value indicated by said counter is said predetermined value or more and also said travel state detector determines that said vehicle is running at a vehicle travel speed higher than or equal to said predetermined travel speed level, said learned value data is written into said nonvolatile ROM and said count value indicated by said counter is initialized.

7. A vehicle control system according to claim 6, wherein said drive detector recognizes actual drive of said vehicle when an engine rotating speed of said vehicle is a predetermined rotating speed level or more.

8. A vehicle control system according to claim 6, further comprising an ordinary RAM not backed up by battery power and a standby RAM backed up by battery power,

wherein, a history of battery disconnection is checked when said ignition switch is turned on, said learned value data stored in said nonvolatile ROM is written into said ordinary RAM when said history of battery disconnection is found, said learned value data stored in said standby RAM is written into said ordinary RAM when said history of battery disconnection is not found, said learned value data stored in said ordinary RAM is updated by means of learning control operation.

9. A vehicle control system according to claim 8, wherein said learned value data stored in said ordinary RAM is written into said standby RAM cyclically when said ignition switch is turned on.

10. A vehicle control system arranged so that operating power is supplied for control of a vehicle when an ignition switch of said vehicle is turned on and learned value data attained through learning control operation of said vehicle is written into an electrically rewritable nonvolatile ROM and retained therein, comprising:

a travel state detector that checks whether or not said vehicle is running at a vehicle travel speed higher than or equal to a predetermined travel speed level,

wherein said learned value data is written into said nonvolatile ROM when said travel state detector determines that said vehicle is running at a vehicle travel speed higher than or equal to said predetermined travel speed.

11. A vehicle control system according to claim 10, wherein said nonvolatile ROM is arranged so that data is written thereinto through a serial data line.

12. A vehicle control system according to claim 10, further comprising a counter that increments upon a vehicle engine operating at or above a predetermined engine rotating speed, said learned value data being written into said non-volatile ROM when said counter increments to a predetermined count.

13. A vehicle control system according to claim 10, further comprising a battery disconnect monitor that monitors battery disconnect status of a vehicle battery and that provides system control parameters corresponding to the status thereof.