Abstract: A system for controlling the speed of an engine in a vocational application is implemented within a mobile cement mixer. The system permits operation of the engine at a high rpm PTO speed to drive the mixing drum at a recommended speed for optimal full mixing of aggregate within the drum. The system maintains the engine at this high rpm only for a predetermined time period necessary for full mixing. After expiration of the time period, the system directs the engine governor to drop the engine speed to low idle, thereby preventing overworking of the cement, reducing the abrasive effect of the aggregate on the interior of the mixing drum, and improving engine fuel economy. In one embodiment, the system permits operator entry of drum rotation speed and total drum revolutions, which are then used to calculate the time period value.

Abstract: A vehicle anti-theft system includes an engine control computer operable to control engine fueling in a normal mode of operation according to operator demand via an accelerator pedal, and a code interface module responsive to a predefined security code to set the engine control computer in a secure mode of operation. In the secure mode, two fuel enabling values in the engine fueling algorithm are altered. Specifically, an engine startup enable value is altered so that the engine control computer disables fueling if the engine is not running, to thereby prevent an unauthorized individual from starting the engine. Likewise, an accelerator enable value is altered so that the engine control computer disregards the accelerator signal and controls fueling of the engine to thereby maintain an engine idling condition. The control computer is reset to its normal fueling control mode by re-entering the security code.