Door control system and method for vehicles

• US 20030095040A1
• Filed: 10/25/2002
• Published: 05/22/2003
• Est. Priority Date: 11/19/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Shimomura, Toshio
• Granted Patent: US 7,190,253 B2
• Time in Patent Office: Days
• US Class Current: 340/426.13
• CPC Class Codes: B60R 25/1004 Alarm systems characterised by the type of sensor, e.g. current sensing means using door lock sensors B60R25/1001
• CPC Class Codes: B60R 25/246 characterised by the challenge triggering
• CPC Class Codes: G07C 2009/00333 and the lock having more than one limited data transmission ranges
• CPC Class Codes: G07C 2009/00373 whereby the wake-up circuit is situated in the lock
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/63 Comprising locating means for detecting the position of the data carrier, i.e. within the vehicle or within a certain distance from the vehicle
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

A door control system for vehicles has a transmitter and a receiver for detecting an electronic key in a first predetermined area around a vehicle. A control unit controls unlocking of a vehicle door by determining whether the detected electronic key is an authorized one. The door control system also has an object sensor for detecting an object entering into a second predetermined area covering and wider than the first predetermined area. The control unit activates the transmitter and the receiver only after the object sensor detects the object in the second predetermined area, thereby reducing power consumption.

Claims

1. A door control system for vehicles comprising:

a transmitter for transmitting an interrogation signal in a first predetermined area of a vehicle door;

a receiver for receiving a response signal generated from an electronic key of a vehicle in response to the interrogation signal;

a control unit for controlling unlocking of the vehicle door by determining whether the electronic key is an authorized one in response to the response signal; and

an object sensor for detecting an object entering into a second predetermined area covering and wider than the first predetermined area, wherein the control unit activates the transmitter and the receiver only after the object sensor detects the object in the second predetermined area.

2. The door control system as in claim 1, further comprising:

an intruder sensor for detecting an intruder, wherein the control unit activates the intruder sensor only after determining that the electronic key is an unauthorized one.

3. The door control system as in claim 2, wherein the control unit deactivates the intruder sensor when the object sensor detects no object in the second predetermined area.

4. The door control system as in claim 2, further comprising:

an alarm, wherein the control unit activates the alarm when the object sensor detects the object but the object has unauthorized key, and when the intruder sensor detects the intruder.

5. The door control system as in claim 4, wherein the control unit activates the alarm with a lower output power when the object sensor detects the object having the unauthorized key than when the intruder sensor detects the intruder.

6. The door control system as in claim 1, wherein the control unit deactivates the transmitter, the receiver and the object sensor, when the door is unlocked.

7. The door control system as in claim 1, the transmitter is mounted in each door of the vehicle.

8. The door control system as in claim 1, wherein the control unit activates the object sensor after the vehicle is parked.

9. A door control method for vehicles comprising the steps of:

activating an object sensor to monitor an object around a vehicle, after the vehicle is parked;

activating a plurality of transmitters for transmitting interrogation signals from different parts of the vehicle, after the object sensor detects the object within a predetermined area around the vehicle;

determining whether the object has an authorized key for the vehicle based on a response signal transmitted from an electronic key in response to the interrogation signal;

enabling a door of the vehicle to be opened, when the object is determined to have the authorized key; and

deactivating the transmitter after the enabling step.

10. The door control method as in claim 9, wherein the object sensor has a monitoring area wider than and covering a signal transmission area of each of the transmitters.