Iveco N60 ENT M37, Technical And Repair Manual, Page: 36 / 194

N60 ENT M37 OVERVIEW
1.36
APRIL 2004
When the engine is in the condition of minimum rpm, the
EDC Central Unit controls the solenoid by a PWM (Pulse
Width Modulation) timely signal to energize the coil and
cause the shifting of the nucleus (2).
The nucleus while shifting moves the spear valve (4) into the
minimum opening position allowing the minimum flow of
fuel to the high pressure pump. The control solenoid is in maximum choking as the common
rail has to be kept at relatively low pressure (from 350 to
400 bar). The cylinder (8) of the low pressure limiter valve,
which controls the opening of the exhaust duct, is in the
maximum opening position in order to allow the fuel in
excessto backflow to the exhaust (9).
Figure 43
Pressure control with engine at minimum rating
1. Coil - 2. Nucleus - 3. Preloading spring - 4. Spear valve - 5. High pressure pump feed - 6. Fuel inlet (from filter) -
7. Fuel backflow form the high pressure pump - 8. Cylinder for exhaust duct opening - 9. Fuel discharge - 10. Fuel delivery.
04_020_N
2
4
3
1
5
6
9 7
8
10