System and method for detecting vehicle speed sensor tampering
First Claim
1. A method for detecting tampering with a vehicle speed sensor, the method comprising:
- determining a current gear ratio;
comparing the current gear ratio to at least one reference gear ratio to determine a gear ratio difference value;
generating an error signal indicating tampering with the vehicle speed sensor when the gear ratio difference value exceeds a first threshold value for a predetermined period of time; and
generating the error signal if the gear ratio difference value exceeds a second threshold without regard to elapsed time, the second threshold being greater than the first threshold.
1 Assignment
0 Petitions
Accused Products
Abstract
A system and method for detecting tampering with a vehicle speed sensor input signal include determining a current gear ratio, comparing the current gear ratio to at least one reference gear ratio to determine a gear ratio difference value, and generating an error signal indicating tampering with the vehicle speed sensor signal when the gear ratio difference value exceeds a first threshold. In one embodiment the step of generating an error signal is performed only when the gear ratio difference value exceeds the first threshold for an elapsed time greater than a predetermined time period. One embodiment includes determining a current engine speed, current vehicle speed, and current transmission gear ratio and storing values for the current engine speed, vehicle speed, and transmission gear ratio in the memory whenever at least one predetermined criterion is satisfied. The system and method calculate difference values between the current engine speed, vehicle speed, and transmission gear ratio and corresponding previously stored respective values. A signal indicating tampering is generated when at least one of the difference values exceeds a corresponding threshold.
39 Citations
21 Claims
-
1. A method for detecting tampering with a vehicle speed sensor, the method comprising:
-
determining a current gear ratio; comparing the current gear ratio to at least one reference gear ratio to determine a gear ratio difference value; generating an error signal indicating tampering with the vehicle speed sensor when the gear ratio difference value exceeds a first threshold value for a predetermined period of time; and generating the error signal if the gear ratio difference value exceeds a second threshold without regard to elapsed time, the second threshold being greater than the first threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method of detecting tampering which affects a vehicle speed sensor signal, the method comprising:
-
determining a current gear ratio; comparing the current gear ratio to at least one reference gear ratio to determine a gear ratio difference value; monitoring current engine speed relative to a reference engine speed to determine an engine speed difference value; resetting the reference gear ratio and the reference engine speed when the gear ratio difference value exceeds a second threshold and the engine speed difference value exceeds a corresponding threshold; and generating an error signal indicating tampering with the vehicle speed sensor signal when the gear ratio difference value exceeds a first threshold.
-
-
13. A method of detecting tampering affecting a vehicle speed sensor input signal, the method comprising:
-
determining a current gear ratio; comparing the current gear ratio to at least one reference gear ratio to determine a gear ratio difference value; monitoring current engine speed relative to a reference engine speed to determine an engine speed difference value; resetting the reference gear ratio and the reference engine speed when the gear ratio difference value approaches zero, the engine speed difference value exceeds a second corresponding threshold, the vehicle speed difference exceeds a corresponding threshold, and the vehicle speed difference value is approximately equal to the engine speed difference value, wherein the vehicle speed difference value and the engine speed difference value are measured as a percentage of the engine speed reference and the vehicle speed reference, respectively; and generating an error signal indicating tampering with the vehicle speed sensor signal when the gear ratio difference value exceeds a first threshold.
-
-
14. A method for detecting tampering with a speed sensor input signal in a vehicle having an engine and a multiple gear ratio transmission, the vehicle also including a vehicle speed sensor for generating a signal indicative of road speed of the vehicle and an engine speed sensor for generating a signal indicative of speed of the engine, the engine speed sensor and the vehicle speed sensor being in communication with a controller having a memory, the method comprising:
-
determining a current engine speed, current vehicle speed, and current transmission gear ratio; storing values for the current engine speed, the current vehicle speed, and the current transmission gear ratio in the memory whenever at least one predetermined criterion is satisfied; calculating difference values between the current engine speed, the current vehicle speed, the current transmission gear ratio and corresponding previously stored values for the engine speed, vehicle speed, and transmission ratio, respectively; generating an error signal indicating tampering with the vehicle speed sensor when at least one of the difference values exceeds a first threshold value for a predetermined period of time; and generating the error signal if at least one ofthe difference values exceeds a second threshold without regard to elapsed time, the second threshold being greater than the first threshold. - View Dependent Claims (15, 16, 17)
-
-
18. A computer readable storage medium having data stored therein, the data representing instructions executable by a computer to detect tampering with a vehicle speed sensor signal input to the computer, the computer readable storage medium comprising:
-
instructions for determining a current engine speed, current vehicle speed, and current transmission gear ratio based on associated signals; instructions for storing values for the current engine speed, the current vehicle speed, and the current transmission gear ratio in the memory, the values being stored whenever at least one predetermined criterion is satisfied; instructions for calculating difference values between the current engine speed, the current vehicle speed, the current transmission gear ratio and corresponding previously stored values for the engine speed, vehicle speed, and transmission gear ratio, respectively; instructions for generating an error signal indicating tampering with the vehicle speed sensor when the gear ratio difference value exceeds a first threshold value for a predetermined period of time; and instructions for generating the error signal if the gear ratio difference value exceeds a second threshold without regard to elapsed time, the second threshold being greater than the first threshold.
-
-
19. A system for detecting tampering with a vehicle speed sensor input signal, the system comprising:
-
a vehicle speed sensor for providing a signal indicative of vehicle speed; an engine speed sensor for generating a signal indicative of engine rotational speed; and control logic in communication with the vehicle speed sensor and the engine speed sensor for determining a current transmission gear ratio based on the vehicle speed sensor, comparing the current transmission gear ratio to at least one reference gear ratio to determine a gear ratio difference value, generating an error signal indicating tampering with the vehicle speed sensor when the gear ratio difference value exceeds a first threshold value for a predetermined period of time, and generating the error signal if the gear ratio difference value exceeds a second threshold without regard to elapsed time, the second threshold being greater than the first threshold. - View Dependent Claims (20, 21)
-
Specification