The 3100 HEUI Diesel Truck Engines Electronic Control System consists of two main components: the Electronic Control Module (ECM) and the Personality Module. The ECM is the computer and the personality module is the software for the computer (the personality module also stores the operating maps that define horsepower, torque curves, rpm, etc.). The two work together (along with sensors to “see” and solenoid/unit injectors to “act”) to control the engine. Neither one can do anything by itself.
The Throttle Position Sensor (TPS) in the truck cab is operated by the driver to accelerate the engine. The signal from the TPS is Pulse Width Modulated (PWM) (see Glossary), and its directed first to the Power Take-Off (PTO) interlock circuit. If the remote PTO is being operated, the interlock prevents the driver in the cab from overriding the remote PTO throttle signal. This protects a pump or other PTO operated device from being over sped. The throttle signal then goes through the throttle/cruise/PTO logic and control circuits, where it is compared with other inputs; vehicle speed, engine rpm and customer parameters.
The signal then goes into the engine control logic circuits. Inputs from the coolant temperature sensor and inlet air temperature sensor are sampled, and if appropriate, the ECM will place the engine in cold mode operation. The output signal is “desired rpm”, which is then routed to the electronic governor circuits.
The PTO application may be operated from a dedicated set of PTO switches in the truck cab, from PTO switches in a remote location, or by a remote PTO on-off switch with a separate throttle position sensor for variable engine speed. The software distinguishes between idle and PTO conditions. There are new parameters available for PTO/vocational applications, such as cement mixers, refuse packers and bulk haulers.
