Mitsubishi 6M60-TL Service Manual page 168

STRUCTURE AND OPERATION
13E-10
(1) Operation
(1.1) Injection not taking place
• With the magnet not energized, the
valve body, is pushed up by the spring
in the magnet such that the ball seat is
closed.
• The high-pressure fuel acts upon the
control chamber via orifice plate. The
same pressure acts upon the nozzle
needle.
• The fuel pressure acting on the nozzle
needle cannot overcome the com-
mand piston and nozzle spring, so the
nozzle needle stays in its downward-
pushed position and injection does not
take place.
(1.2) Start of injection
• When the magnet is energized, the re-
sulting electromagnetic force draws
the valve body upward, causing the
ball seat to open.
• Fuel in the control chamber passes
through the orifice plate and ball seat
and flows to the fuel tank.
• With the pressure in the control cham-
ber reduced, the fuel acting on the
nozzle needle overcomes the com-
mand piston and nozzle spring, push-
ing up the nozzle needle such that
injection starts.
• If the magnet remains energized, the
injection rate reaches its maximum
level.