Engine System Overview 2 Engine System Overview All of the engines covered in this document are designed for electronic control. The electronic engine control system consists of the following primary components: Electronic Control Unit (ECU), electronically controlled unit injectors, engine wiring harness, and sensors. The following sections will provide information to better understand the function of the components in the engine control system and basic understanding of electronic engine control.
2.1 Electronic Engine Control The electronic engine control strategy determines the timing and amount of fuel that is delivered to each cylinder based on the actual and desired conditions at any given time. The objective of the control system is to deliver best performance within emission and engine operating limits. Following are the primary functions performed by the electronic engine control strategy: 2.1.1 Engine Governing The engine governor determines how much fuel to deliver to each cylinder to respond to changes in operator demand or engine load conditions. Two governing strategies are available: Speed Governor and Min/Max Governor.
Governor strategy is selectable through a programmable parameter. Refer to Engine Governor (section 13) for additional information. 2.1.2 Air to Fuel Ratio Control The control system has full authority over engine fuel delivery. The mechanical fuel/air ratio control is eliminated on an electronically controlled engine. Electronic control of the fuel/air ratio provides optimum performance while limiting emissions. 2.1.3 Injection Timing Control Injection timing is varied as a function of engine operating conditions to optimize engine performance for emissions, noise, fuel consumption, and driveability.
2.1.4 Torque Rise Shaping Electronic controls provide increased flexibility to tailor the torque curve over a wide speed range. 2.1.5 Cold Starting Strategy Before and during cranking, the engine monitors atmospheric pressure, air inlet temperature, and/or coolant temperature. Based on these inputs, the engine executes a complex cold starting strategy that adjusts fuel volume, timing, and starting aids in order to start the engine. Refer to Cold Starting Aid (Section 16) for more information. Also, refer to the Operation and Maintenance Manual and the Troubleshooting Guide for the engine for more information. I N D U S T R I A L E N G I N E E L E C T R O N I C S 6