To control an engine means to keep it running at a desired speed, either in accordance with, or regardless of, the changes in the load carried by the engine. The degree of control required depends upon two factors: the engine’s performance characteristics, and the type of load which it drives.
Control of a diesel engine is accomplished through several components: the camshaft, the fuel injector pump, fuel injector and the governor. The camshaft provides the timing needed to properly inject the fuel, the fuel injector pump provides the components that meters and injects the fuel, and the governor regulates the amount of fuel that the injector is to inject. Together, these three major components ensure that the engine runs at the desired speed.
In diesel engines, a varying amount of fuel is mixed with a constant amount of compressed air inside the cylinder. A full charge of air enters the cylinder during each intake event. The amount of fuel injected into the cylinders controls combustion and thus determines the speed and power output of a diesel engine.
A governor is provided to regulate the flow of fuel. Other devices, either integral with the governor or mounted separately on the engine, are used to control overspeed or overload.
