On-board control system and method for vehicles

• US 20020177931A1
• Filed: 05/21/2002
• Published: 11/28/2002
• Est. Priority Date: 05/24/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kikukawa, Hiroshi, Iwasaki, Tatsuya, Takagi, Nobutomo
• Granted Patent: US 6,791,463 B2
• Time in Patent Office: Days
• US Class Current: 701/36
• CPC Class Codes: B60R 16/03 for supply of electrical power to vehicle subsystems or for circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: E05B 77/12 Automatic locking or unlocking at the moment of collision
• CPC Class Codes: E05B 81/86 using capacitors
• CPC Class Codes: H02J 2310/46 for ICE-powered road vehicles
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02J 9/061 for DC powered loads

Abstract

In an on-board control system, a body ECU executes various control operations in response to the supply of power voltage from a battery. There is connected on the power line of the battery a voltage holding circuit which is formed of a capacitor so that the variation of battery voltage slows. A switch input circuit samples the on/off states of external switches periodically under control of a microcomputer. The microcomputer determines a fall of battery voltage, causing the switch input circuit to stop sampling of switch states. Stopping the circuit operation and thus reducing the battery load current slows the voltage fall at the occurrence of collision of vehicle, allowing adequate time to store collision data in a collision memory circuit.

Claims

1. An on-board control system which performs a plurality of control operations in response to supply of a power voltage from an on-board power source, with a voltage holding capacitor for slowing variation of the power voltage, the control system comprising:

determination means which determines a fall of power voltage; and

operation stopping means which stops any of the control operations selectively at a fall of the power voltage.

2. An on-board control system according to claim 1, further comprising:

a plurality of switches which are pulled up to the voltage of the on-board power source; and

an input processing circuit which detects the states of the switches periodically,

wherein the operation stopping means stops operation of the input processing circuit at a fall of the power voltage.

3. An on-board control system according to claim 2, wherein control outputs to other actuators are kept unchanged when the operation stopping means stops the operation of the input processing circuit.

4. An on-board control system according to claim 1, further comprising:

a collision memory circuit which memorizes an event of collision at occurrence of collision of vehicle at a fall of the power voltage caused by the collision and stopping any of other control operations.

5. An on-board control system according to claim 4, wherein the collision memory circuit includes a capacitor which is charged at the occurrence of collision, and the occurrence of collision is determined based on a charge of the capacitor.

6. An on-board control method for a vehicle having a battery, a power holding circuit for holding a battery voltage, a collision sensor and a collision memory, the control method comprising steps of:

monitoring the battery voltage;

stopping a part of a vehicle control performed with the battery voltage when the monitored voltage falls below a predetermined threshold, so that rate of fall of the battery voltage is slowed; and

storing a collision detected by the collision sensor in the collision memory with the battery voltage of the power holding circuit.

7. An on-board control method according to claim 6, wherein the storing step charges a capacitor when the collision is detected.

8. An on-board control method according to claim 6, further comprising steps of:

checking a record of collision stored in the collision memory; and

unlocking doors when the record of collision is detected.

9. An on-board control method according to claim 6, wherein the stopping step stops sampling of conditions of input switches as the part of the vehicle control and holds control conditions of the vehicle unchanged.