Abstract
DENSO and TOYOTA have developed a common rail injection system named ECD-U2P for modern high speed direct-injection diesel engines.
The components of this system include a new high pressure supply-pump, ECU/EDU, and injectors which accommodate a precise control two-way valve. The ECD-U2P system can control the injection pressures up to 135MPa at all engine operating conditions. The injector size was made smaller by reducing the solenoid force, and fuel leakage from the injector was decreased with a flat-seat valve. The high pressure supply-pump has adopted inlet-metering valves which contribute to a reduction in the pump driving torque at partial load, and reduction of the fuel temperature increase in the fuel tank.
Furthermore, the high pressure pump has two pumping circuits in tandem. These tandem pumping circuits contribute to a reduced peak driving torque and reduction in the belt tension for the engine.