Antitheft system for vehicle

• US 20060082435A1
• Filed: 03/26/2004
• Published: 04/20/2006
• Est. Priority Date: 03/27/2003
• Status: Active Grant

• Current Assignee: Kubota Corporation
• Original Assignee: Kubota Corporation
• Inventors: Miura, Keisuke, Matsumoto, Atsushi, Nishi, Eiji
• Granted Patent: US 7,280,034 B2
• Time in Patent Office: Days
• US Class Current: 340/5.230
• CPC Class Codes: B60R 25/04 operating on the propulsion system, e.g. engine or drive motor
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user

Abstract

It is possible to start engine economically and easily without deteriorating the theft prevention function even when an engine start key is lost. A vehicle theft prevention system includes permission tools (5C, 5D) for permitting rewrite or write-in of an ID code. The system has a start key registration function for corresponding the ID code of an engine key (5) to the ID code of an immobilizer control section (17), so that the engine key (5) functions as an engine start key (5A, 5B) when the ID code of the permission tools (5C, 5D) is correlated with the ID code recorded in the immobilizer control section (17) and matching is established. Accordingly, when the engine start key is lost or the like, a new engine start key is created for starting the engine economically and easily without requiring replacement of the entire theft prevention device.

Claims

1. An antitheft system for a vehicle configured to collate an ID code of an engine start key (5A, 5B) with an ID code recorded in an immobilizer control unit (17), and to allow the engine start key (5A, 5B) to start an engine when a result of a collation is affirmative, the system comprising:

an allowance tool (5C, 5D) for allowing rewriting or writing of an ID code, the allowance tool being provided separately from the engine start key (5A, 5B), the allowance tool (5C, 5D) being incapable of starting an engine while the engine start key (5A, 5B) being incapable of allowing rewriting or writing of an ID code; and

a start key registration function of collating an ID code of the allowance tool (5C, 5D) with the ID code recorded in the immobilizer control unit (17) without starting engine and without requiring any special manipulation with the key, and rendering an ID code of an engine key (5) corresponding to the ID code of the immobilizer control unit (17) when the result of the collation is affirmative, so that when the engine key (5) is inserted into a key cylinder (3), the inserted engine key (5) serves as the engine start key (5A, 5B).

5. An antitheft system for a vehicle according to claim 1, further comprising a copy function of writing the ID code of the allowance tool (5D) recorded in the immobilizer control unit (17) into another member to cause the member to serve as an allowance tool.

8. An antitheft system for a vehicle according to claim 1, wherein the ID code of the engine start key (5B) registered by the start key registration function can be recorded as an engine start key into an immobilizer control unit of another vehicle.

9. An antitheft system for a vehicle according to claim 8, further comprising a start key copy function of writing the ID code of the engine start key (5) into another engine key (5) to cause the engine key to serve as the engine start key.

10. An antitheft system for a vehicle according to claim 9, wherein the start key copy function of the immobilizer control unit (17) writes the ID code of the engine start key (5B) into another engine key (5) to cause the engine key to serve as the engine start key, when the engine key (5) is inserted into a key cylinder (3) after the engine start key (5B) is inserted into the key cylinder (3).

11. An antitheft system for a vehicle according to claim 1, further comprising a delete function of deleting the ID code of the engine start key (5A, 5B) recorded in the immobilizer control unit (17) from the immobilizer control unit (17).

12. An antitheft system for a vehicle according to claim 1, further comprising an engine start function with a special manipulation in which the engine is allowed to start when the engine key (5) is inserted into a key cylinder (3) and a special manipulation is performed.

13. An antitheft system for a vehicle according to claim 1, further comprising an initialization function in which an ID code recording portion of the immobilizer control unit (17) is initialized.

16. An antitheft system for a vehicle according to claim 9, wherein when a master key of the engine start key (5B) is inserted into a key cylinder (3), a control mode for rendering the start key copy function operable is actuated.

17. An antitheft system for a vehicle according to claim 1, wherein a vehicle to which the antitheft system is applied is a work machine such as a backhoe.

2. An antitheft system for a vehicle configured to collate an ID code of an engine start key (5A, 5B) with an ID code recorded in an immobilizer control unit (17), and to allow the engine start key (5A, 5B) to start an engine when a result of a collation is affirmative, or to prevent the engine start key (5A, 5B) from starting the engine when the result of the collation is negative, the system comprising:

an allowance key (5C, 5D) for allowing rewriting or writing of an ID code, the allowance key being provided separately from the engine start key (5A, 5B), the allowance key (5C, 5D) being incapable of starting an engine while the engine start key (5A, 5B) being incapable of allowing rewriting or writing of an ID code; and

a start key registration function of collating an ID code of the allowance key (5C, 5D) with the ID code recorded in the immobilizer control unit (17) without starting engine and without requiring any special manipulation with the key, and rendering an ID code of an engine key (5) corresponding to the ID code of the immobilizer control unit (17) when the result of the collation is affirmative, so that when the engine key (5) is inserted into a key cylinder (3), the inserted engine key (5) serves as the engine start key (5A, 5B).

4. An antitheft system for a vehicle according to claim 2, wherein the start key registration function renders the ID code of the engine key (5) corresponding to the ID code of the immobilizer control unit (17), when the engine key (5) is inserted into a key cylinder (3) after the allowance key (5C, 5D) is inserted into the key cylinder (3), so that the engine key (5) serves as the engine start key (5A, 5B).

6. An antitheft system for a vehicle according to claim 2, further comprising an allowance key copy function of writing the ID code of the allowance key (5D) into another engine key (5) to cause the engine key to serve as an allowance key.

7. An antitheft system for a vehicle according to claim 6, wherein the allowance key copy function of the immobilizer control unit (17) writes the ID code of the allowance key (5D) into another engine key (5) to cause the engine key to serve as the allowance key, when the engine key (5) is inserted into a key cylinder (3) after the allowance key (5D) is inserted into the key cylinder (3).

14. An antitheft system for a vehicle according to claim 2, wherein after the allowance key (5C, 5D) is inserted into a key cylinder (3), the ID code of the allowance key (5C, 5D) is collated with the ID code recorded in the immobilizer control unit (17), and when the result of the collation is affirmative, a control mode for rendering the start key registration function operable is actuated.

15. An antitheft system for a vehicle according to claim 6, wherein when a master key of the allowance key (5D) is inserted into a key cylinder (3), a control mode for rendering the allowance key copy function operable is actuated.

3. An antitheft system for a vehicle configured to collate an ID code of an engine start key (5A, 5B) with an ID code recorded in an immobilizer control unit (17), and to allow the engine start key (5A, 5B) to start an engine when a result of a collation is affirmative, or to prevent the engine start key (5A, 5B) from starting the engine when the result of the collation is negative, the system comprising:

an allowance key (5C, 5D) for allowing rewriting or writing of an ID code, the allowance key being provided separately from the engine start key (5A, 5B), the allowance key (5C, 5D) being incapable of starting an engine while the engine start key (5A, 5B) being incapable of allowing rewriting or writing of an ID code;

a start key registration function of collating an ID code of the allowance key (5C, 5D) with the ID code recorded in the immobilizer control unit (17) without starting engine and without requiring any special manipulation with the key, and rendering an ID code of an engine key (5) corresponding to the ID code of the immobilizer control unit (17) when the result of the collation is affirmative, so that when the engine key (5) is inserted into a key cylinder (3), the inserted engine key (5) serves as the engine start key (5A, 5B); and

a cryptographic code for specifying the engine key (5) and an discrimination code for distinguishing kind of the engine key (5) recorded as ID codes in the engine key (5) and the immobilizer control unit (17), the discrimination code enabling the system to distinguish the engine start key (5A, 5B) for starting the engine and the allowance key (5C, 5D) for allowing the rewriting or writing of the ID codes.