2) Cleanness
(1) Cleanness of DI engine fuel system
Cleanness of DI engine fuel system and service procedures
The fuel system for DI engine consists of transfer (low pressure) line and high pressure line.
Its highest pressure reaches over 1,600 bar.
preciseness.
The pressure regulation and injector operation are done by electric source from engine ECU.
Accordingly, if the internal valve is stuck due to foreign materials, injector remains open.
Even in this case, the HP pump still operates to supply high pressurized fuel. This increases the
pressure to combustion chamber (over 250 bar) and may cause fatal damage to engine.
You can compare the thickness of injector nozzle hole and hair as shown in below figure (left side). The
below figure shows the clearance between internal operating elements.
The core elements of fuel system has very high preciseness that is easily affected by dust or very small
foreign material. Therefore, make sure to keep the preliminary works and job procedures in next pages.
If not, lots of system problems and claims may arise.
Hair
Nozzle holeValve actuator lift - 0.028 mm
Diameter
0.04 mm
Operating
clearance
0.002 mm
Diameter
2.0 mm
