System for controlling engine speed in response to detection of vehicle speed signal tampering

A method of controlling engine speed in response to defection of vehicle speed signal tampering in a vehicle having an engine, a transmission having a plurality of gears, a vehicle speed sensor for sensing vehicle speed and providing a vehicle speed signal corresponding thereto, an engine speed sensor for sensing engine speed and providing an engine speed signal corresponding thereto, and an electronic engine controller having a memory associated therewith, the method comprising the steps of:

• (1) monitoring the vehicle speed signal and the engine speed signal and determining therefrom a transmission gear ratio;
• (2) determining that a vehicle speed signal tampering condition exists and logging an active vehicle speed signal fault code within the memory if said transmission gear ratio exceeds a predefined top gear ratio by at least a predetermined percentage of said predefined top gear ratio for a first time period;
• and
• (3) electronically controlling the engine speed to a predefined maximum engine speed in response to logging said active vehicle speed signal fault code.

A method of controlling engine speed in response to detection of vehicle speed signal tampering in a vehicle having an engine, a transmission having a plurality of gears, a vehicle speed sensor for sensing vehicle speed and providing a vehicle speed signal corresponding thereto, an engine speed sensor for sensing engine speed and providing an engine speed signal corresponding thereto, and an electronic engine controller having a memory associated therewith, the method comprising the steps of;

• (1) periodically sensing the vehicle and engine speed signals and determining therefrom a transmission gear ratio;
• (2) comparing said transmission gear ratio with the previously determined transmission gear ratio;
• (3) comparing the vehicle speed signal with the previously sensed vehicle speed signal;
• (4) determining that a vehicle speed signal hampering condition exists and logging an active vehicle speed signal fault code within the memory if, for at least a first time period, the transmission gear ratio deviates from the previously determined transmission gear ratio by more than a gear ratio threshold value and the vehicle speed signal does not deviate from the previously sensed vehicle speed signal by more than a vehicle speed threshold value;
• and
• (5) electronically controlling the engine speed to a predefined maximum engine speed in response to logging said active vehicle speed signal fault code.

A method of controlling engine speed in response to detection of vehicle speed signal tampering in a vehicle having an engine, a transmission having a plurality of gears, a vehicle speed sensor for sensing vehicle speed and providing a vehicle speed signal corresponding thereto, an engine speed sensor for sensing engine speed and providing an engine speed signal corresponding thereto, and an electronic engine controller having a memory associated therewith, the method comprising the steps of:

• (1) periodically monitoring the vehicle speed and engine speed signals;
• (2) determining from the vehicle and engine speed signals whether a constant transmission out-of-gear condition exists if the transmission is a manual transmission;
• (3) determining a first transmission gear ratio from the vehicle and engine speeds if the transmission is one of an automatic transmission and a particular manual transmission, wherein the particular manual transmission is operable to provide the vehicle with strictly an on-highway application;
• (4) determining a second transmission gear ratio from the vehicle and engine speed signals, comparing said second transmission gear ratio with the previously determined second transmission gear ratio and comparing the vehicle speed signal with the previously sensed vehicle speed signal, if the transmission is a manual transmission:
• (5) determining that a vehicle speed signal tampering condition exists and logging an active vehicle speed signal fault code within the memory if one of the constant transmission out-of-gear ratio condition exists for at least a first time period, the first transmission gear ratio exceeds a predefined top gear ratio by at least a predetermined percentage of said predefined top gear ratio for at least a second time period and, for at least a third time period, the second transmission gear ratio deviates from the previously determined second transmission gear ratio by more than a gear ratio threshold value and the vehicle speed does not deviate from the previously sensed vehicle speed by more than a vehicle speed threshold value;
• and
• (6) electronically controlling the engine speed to a predefined maximum engine speed in response to logging said active vehicle speed signal fault code.