2.3 Fuel System and Control System [1] Fuel System This system comprises the route through which diesel fuel flows from the fuel tank to the sup- ply pump, via the rail, and is injected through the injector, as well as the route through which the fuel returns to the tank via the overflow pipe. [2] Control System In this system, the engine ECU controls the fuel injection system in accordance with the sig- nals received from various sensors. The components of this system can be broadly divided into the following three types: (1) Sensors; (2) ECU; and (3) Actuators. (1) Sensors a. Detect the engine and driving conditions, and convert them into electrical signals. (2) Engine ECU a.
Performs calculations based on the electrical signals received from the sensors, and sends them to the actuators in order to achieve optimal conditions. (3) Actuators a. Operate in accordance with electrical signals received from the ECU. Injection system control is undertaken by electronically controlling the actuators. The injection quantity and timing are determined by controlling the length of time and the timing in which the current is applied to the TWV (Two-Way Valve) in the injector. The injection pressure is determined by controlling the SCV (Suction Control Valve) in the supply pump.
Sensor Actuator Engine Speed Crankshaft Position Sensor NE Injector Cylider Recognition Sensor G Cylinder Recognition •Injection Quantity Control •Injection Timing Control Accelerator Position Sensor Load Engine ECU Supply Pump (SCV) Rail Pressure Sensor •Injection Pressure Control EGR, Engine Warning Light Other Sensors and Switches Q000282E 5