Yanmar 4LHA-HTP Operation Manual page 400

Chapter 3 Fuel Injection Equipment
8. Magnet Valve
8. Magnet Valve
Fuel oil passage
Fig. 52 Magnet valve construction and operation
The magnet valve is turned on and off by the
vehicle's ignition switch to open and close the
fuel oil passage leading to the plunger barrel's
inlet port.
When the ignition switch is ON, current flows
through the magnet valve, the armature in the
centre of the magnet valve is attracted up-
wards and fuel oil from the pump chamber is
V
Magnet valve
Armature
During Operation
Spring
Inlet port
IHI
At Stopping
supplied to the plunger barrel's inlet port.
When the ignition switch is turned OFF, the
force of the spring inside the armature moves
the armature downwards. Therefore, the fuel
passage leading to the plunger barrel's inlet
port is blocked and, as fuel oil injection to the
engine combustion chamber is prevented, the
engine can be stopped immediately.
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