Electronically controlled pumps

There are two types of electronically controlled fuel injection pumps available: the distributor type and the common rail type. The injection method is completely different from conven-tional fuel injection pumps such as in-line pump types.

Distributor (rotary) fuel injection pump

The electronic control system of the distributor type pump consists of various sensors, an ECU (computer) and an actuator. The system detects the running condition of the engine, using the sensors while the ECU controls both fuel injection quantity and injection timing. The actua-tor controls the injection quantity and the injection timing according to the signal sent from the ECU. This ECU calculates the optimum injection quantity and injection timing for the current running condition of the engine using signals from the sensors.

Common rail fuel injection pump (supply pump)

The common rail type pump is completely different from conventional fuel injection pumps. This type has been developed to meet strict exhaust gas regulations in the 21st century. This system consists of a supply pump, common rail, electronically controlled injectors, various sensors to detect the running condition of the engine and a computer (ECU) to control these devices.

The supply pump is driven by the engine and produces high-pressure fuel. An injector is mounted on each cylinder of the engine and the high-pressure fuel from the supply pump is distributed to each injector by the common rail.