Methods and apparatus for providing security for electronically-controlled cylinder activation and deactivation

DETAILED DESCRIPTION In accordance with the teachings of the present invention security methods and apparatus are provided for ensuring that a throttle increase accompanying a decrease in the number of active cylinders of an internal combustion engine will be limited to a predetermined threshold period with more than a selected fraction of all the cylinders of the engine being activated.
The apparatus comprises an electronic controller that generates the throttle increase if less than all the cylinders are requested to be activated.
A query is made to determine if the number of cylinders being fueled is equal to or less than the selected fraction.
A timer is started if the number of cylinders being fueled is greater than the selected fraction of all the cylinders.
The throttle increase is turned off if the amount of time measured by the timer exceeds the predetermined threshold before the number of cylinders being fueled becomes either less than or equal to the selected fraction.