Vehicle security system

• US 4,932,494 A
• Filed: 11/14/1988
• Issued: 06/12/1990
• Est. Priority Date: 01/22/1987
• Status: Expired due to Fees

• Current Assignee: System Control Engineering Limited
• Original Assignee: System Control Engineering Limited
• Inventors: Chandler, David R.
• Primary Examiner(s): Bertsch, Richard A.
• Application Number:
  US07/275,051
• Time in Patent Office: 575 Days
• Field of Search: 180/277, 180/284, 180/287, 70/243, 340/63, 137/351, 307/10 AT
• US Class Current: 180/287
• CPC Class Codes: B60R 25/042 operating on the fuel supply

Abstract

A vehicle security system is disclosed which includes a code entry module and a decoding module. The decoding module is preferably a sealed module mounted within the fuel tank of the vehicle and arranged so as normally to disable the vehicle fuel system (e.g., a fuel pump or fuel valve mounted within the fuel tank) and further arranged to respond to a predetermined access code being entered on the code entry module to enable the fuel system for normal running of the vehicle.

Claims

1. A vehicle security system comprising a code entry module and a decoding module, the decoding module being a sealed module mounted within a fuel tank of the vehicle and arraned so as normally to disable the vehicle fuel system and further arranged to respond to a predetermined access code being entered on the code entry module to enable the fuel system for normal running of the vehicle.

2. A vehicle security system as claimed in claim 1, in which the decoding module is arranged to open an electrically operable valve in a fuel line leading from the fuel tank.

3. A vehicle security system as claimed in claim 1, in which the decoding module is arranged to enable an electrical fuel pump in a fuel line leading from the fuel tank.

4. A vehicle security system as claimed in claim 1, in which the decoding module comprises a memory storing an individual code and a comparator for comparing a code entered on the code entry module with said stored code, and to enable the fuel system in the event of agreement between the entered code and the stored code.

5. A vehicle security system as claimed in claim 1, arranged to provide a signal for enabling an ignition coil of the vehicle in response to the predetermined code being entered on the code entry module.

6. A vehicle security system as claimed in claim 1, comprising means for changing the required access code using the code entry module.

7. A vehicle security system as claimed in claim 6, in which said code-changing means functions such that the decoding module responds alternatively to the previous access code until the new access code has been used a predetermined number of times.

8. A vehicle security system as claimed in claim 1, comprising means for enabling the decoding module upon entry of another predetermined code on the code entry module, to allow the fuel system to be enabled without entering the normally-required access code.

9. A vehicle security system as claimed in claim 1, comprising means for disabling the code entry module following a predetermined number of successive attempts to access the system if those successive attempts all fail.

10. A vehicle security system as claimed in claim 1, in which the code entry module comprises "engine start" and "engine stop" keys and means are provided to render these keys operative only after the system has been enabled by entry of the correct access code.