Method and apparatus for enhanced vehicle protection

• US 5,637,929 A
• Filed: 01/16/1996
• Issued: 06/10/1997
• Est. Priority Date: 01/16/1996
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Motor Company
• Inventors: Treharne, William D.
• Primary Examiner(s): Elms, Richard T.
• Application Number:
  US08/586,448
• Time in Patent Office: 511 Days
• Field of Search: 307/9.1-10.6, 180/287, 180/289, 70/237, 70/277, 70/228, 70/252, 70/370, 340/425.5, 340/426, 340/825.3-825.32, 340/825.34, 340/825.44, 340/825.54, 340/825.69, 340/825.72, 123/198 DB, 123/198 DC
• US Class Current: 307/10.5
• 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

A security system for an automotive vehicle having an engine is operatively connected between engine running electrical components that are connected to an electrical power source and a lock switch having at least two operative positions. The security system has a lock switch operator having a memory device carried thereon with a first security code stored in the memory device. A theft control module having a memory storing a second security code is operatively connected between the switch and the engine running electrical devices. The theft control module operates to first permit the engine running electrical components to enable the starting of the engine and then to compare the first and second security codes. Before starting the engine, a counter is compared to a predetermined number so that the engine starting is limited to only a predetermined number of attempts. The engine is disabled if the number of attempts exceeds the predetermined number. If the predetermined number is not exceeded the security codes are checked. Upon finding the first security code not equal to the second security code, the engine running electrical components are disconnected from the electrical power source to disable the engine. The system also may have a feature to allow the electronic engine controller to generate a code and send the code to the theft control module. The theft control module calculates a response based upon a secret algorithm. The electronic engine controller maintains the engine enabled if a code it calculates based on the same secret algorithm is equivalent to the response calculated in the theft control module.

Claims

1. A security system for an automotive vehicle having an engine, said security system operatively connected between engine running electrical components and an electrical power source, said security system comprising:

a lock switch having an operative position;

a lock switch operator;

a memory device carried on said lock operator having a first security code;

an engine control module coupled to said engine running electrical components and having a counter for counting an attempted start count; and

a theft control module having a memory storing a second security code, said theft control module operatively connected to said lock switch for receiving said first security code, said theft control module comparing said first and second security codes and transmitting the result of said comparison to said engine control module;

wherein said engine control module compares an attempted start count to a predetermined number, and wherein if said attempted start count is less than said predetermined number then said engine control module energizes said engine running electrical components to enable the starting of said engine and if said theft control module subsequently indicates that said first and second security codes are not equal then disconnecting said engine running electrical components from said electrical power source thereby discontinuing operation of said engine; and

wherein said engine control module transmits a challenge code to said theft control module, wherein said theft control module calculates a response code according to a predetermined formula and transmits said response code to said engine control module, wherein said engine control module calculates a comparison code and compares said response code to said comparison code, and wherein said engine control module disables said engine if said response code is not equal to said comparison code.

2. A security system for an automotive vehicle as recited in claim 1 wherein said engine control module includes nonvolatile memory for storing said attempted start count.

3. A security system for an automotive vehicle as recited in claim 2 wherein said nonvolatile memory is comprised of keep alive memory.

4. A security system for an automotive vehicle as recited in claim 2 wherein said nonvolatile memory is comprised of an EEPROM.

5. A security system as recited in claim 1 wherein said predetermined number is about five.

6. A security system as recited in claim 1 wherein said attempted start count is incremented if said first security code is not equal to said second security code.

7. A method for operating a security system for an automotive vehicle having an engine including engine running electrical components and an electronic engine controller, said automotive vehicle including a lock switch having a selected position providing power to said engine running electrical components to run said engine, said security system having a theft control module operatively connected between said electronic engine controller and said lock switch, said theft control module having a memory storing a first security code and having means for communicating with a switch operator storing a second security code, said method comprising the steps of:

placing said lock operator in said lock switch in said selected position;

starting said engine;

operating said theft control module to interrogate said lock operator for said second security code;

receiving said second security code into said theft control module;

comparing said first security code with said second security code;

if said first security code equals said second security code, then;

signaling said electronic engine controller of said equality;

generating a challenge code in said electronic engine controller;

transmitting said challenge code to said theft control module;

calculating a response code in said theft control module based on a secret algorithm operating on said challenge code;

transmitting said response code to said electronic engine controller;

receiving said response code in said electronic engine controller;

calculating a comparison code in said electronic engine controller based on said secret algorithm;

comparing said response code to said comparison code; and

maintaining power to said engine running electrical components if said comparison code equals said response code, otherwise disabling said power to said running electrical components.

8. A method for operating a security system as recited in claim 7 wherein said electronic engine controller comprises a counter for counting an attempted start count, said method further comprising the steps of:

comparing said attempted start count to a predetermined number; and

disabling said engine from running if said attempted start count exceeds said predetermined number.

9. A method for operating a security system as recited in claim 8 wherein said predetermined number is about 5.

10. A method for operating a security system as recited in claim 8 further comprising the step of resetting said attempted start count if said comparison code equals said response code.