US 5,796,179 A · Vehicle anti-theft device with low voltage compensation and a rolling code

Abstract

A vehicle theft-prevention device which includes an ignition key having a transponder, a coil unit for supplying power to the transponder when the ignition key is inserted into the coil unit and then turned to a starting position thereby permitting the transponder to generate an identification code. The coil unit outputs the identification code to a disabling controller and the disabling controller outputs an engine drive signal when the identification code from the coil unit is valid and outputs an engine stop signal when the identification code is invalid. The vehicle theft prevention device also includes an engine controller for permitting an engine starting operation to continue when the engine drive signal is input into the engine controller from the disabling controller within a predetermined communication time period from a moment the engine starting operation is initiated by turning the ignition key to the start position. The disabling controller and the engine controller are each provided with respective low-voltage communication modules for communicating therebetween when a battery voltage is less than a predetermined low-voltage level after the engine starting operation is initiated.

Claims13

Dependent claims

A vehicle theft-prevention device comprising:

an ignition key having a transponder;
a coil unit for supplying power to said transponder when said ignition key is inserted into said coil unit and then turned to a starting position thereby permitting said transponder to generate an identification code;
said coil unit outputting said identification code to a disabling controller wherein said disabling controller outputs an engine drive signal when said identification code from said coil unit is valid and outputs an engine stop signal when said identification code is invalid;
and an engine controller for permitting an engine starting operation to continue when said engine drive signal is input into said engine controller from said disabling controller within a predetermined communication time period from a moment said engine starting operation is initiated by turning said ignition key to said start position;
wherein said disabling controller and said engine controller are provided with respective low-voltage communication circuits for communicating therebetween when a battery voltage is less than a predetermined low-voltage level after said engine starting operation is initiated.

2 more elements

In a vehicle theft-prevention device including a transponder associated with an ignition key which outputs a predetermined identification code in response to power supplied to the transponder when the ignition key is positioned within a key cylinder and turned to a starting position, in which said predetermined identification code corresponds with key serrations of said key, a disabling controller which outputs a predetermined rolling authorization code in response to a valid identification code received from the transponder, and an engine controller which permits an engine starting operation to continue when the rolling authorization code received from the disabling controller is valid and which prevents an engine from starting when the rolling authorization code is invalid or when no rolling authorization code is received from the disabling controller within a predetermined period of time, wherein the improvement comprises:

means for storing a present rolling authorization code from the disabling controller as a previous rolling authorization code from the disabling controller and for storing a present rolling authorization code from the engine controller as a previous rolling authorization code from the engine controller when said present rolling authorization code from the disabling controller matches said present rolling authorization code from said engine controller;
and
means associated with the disabling controller for determining whether or not said previous rolling authorization code from the disabling controller and said previous rolling authorization code from said engine controller match when said present rolling authorization code from the disabling controller does not match said present rolling authorization code from the engine controller.

In a vehicle theft-prevention device including a transponder associated with an ignition key which outputs a predetermined identification code in response to power supplied to the transponder when the ignition key is positioned within a key cylinder and turned to a starting position, a disabling controller which outputs a predetermined rolling authorization code in response to a valid identification code received from the transponder, and an engine controller which permits an engine starting operation to continue when the rolling authorization code received from the disabling controller is valid and which prevents an engine from starting when the rolling authorization code is invalid or when no rolling authorization code is received from the disabling controller within a predetermined period of time, wherein the improvement comprises:

a first storage device associated with the disabling controller for storing a first rolling authorization code;
a second storage device associated with the engine controller for storing a second rolling authorization code;
and
means associated with the engine controller for generating a first shifted address within said first storage device and a second shifted address within said second storage device so as to store said first and said second rolling authorization codes at said first and said second shifted addresses, respectively.

1 more element

Dependencies are inferred from the claim text.

Vehicle anti-theft device with low voltage compensation and a rolling code

Life of this patent

Vehicle anti-theft device with low voltage compensation and a rolling code

Life of this patent

Abstract

Claims13