Prior to the introduction of Electronically Controlled Diesel (ECD) injection systems, DENSO was a supplier of both inline and rotary (VE) mechanical diesel fuel injection pumps. DENSO continues to supply this technology as required by some manufacturers which is renowned for its quality and component durability.
The DENSO diesel fuel injection pumps commonly used in Australia for new vehicles at present are the ECD-V3 and ECD-V4 which are both electronically controlled distributor types. A number of vehicles in Australia are now equipped with the DENSO common rail system.
Electronically Controlled Diesel Model (ECD-V3)
The distributor-type pump was developed in response to the demand for lighter, more compact pumps for the smaller car engines now available. This type of pump injects and distributes the fuel into each cylinder with one rotation of the plunger. Features of the ECD-V3 include the control of the fuel injection volume by the Solenoid Spill Valve (SPV), and the control of the fuel injection timing by the Timing Control Valve (TCV).
Electronically Controlled Diesel Model (ECD-V4)
While the ECD-V3 and mechanical-type pumps use a face cam mechanism for fuel plunging, the ECD-V4 uses an inner cam mechanism to achieve the desired injection pressure of approximately 130Mpa. The rollers revolve in the inner circumference of the cam ring, creating a reciprocal movement of the plungers and generating high pressure.
In response to demands for lower emissions and greater performance, DENSO developed a common rail injection system achieves the world's highest injection pressure of 1,800 bar. The common rail type pump is completely different from conventional fuel injection pumps. 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.