Fuel Supply System - Yanmar 4LHA-HTP Operation Manual

Chapter s Fuel Injection Equipment

1. Fuel Supply System

1. Fuel Supply System
1-1 Fuel s u p p l y system
The YPES-AL fuel injection pumps are in-line. The
engine gears drive the camshaft via the timing gears.
The camshaft then drives the feed pump, pumping fuel
from the tank to the filter at a pressure of
0.118(1.2)MPa(kg-f/cm'). The filtered fuel is fed to the
reservoir in t h e pump housing, where the plunger
raises its pressure. The fuel then passes through the
injection pipe for injection into each cylinder via the fuel
injection nozzle.
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The Model Y P E S - A L fuel injection pump is an in-line
pump with a governor.
A camshaft is built into the pump. There are a drive
cam for the fuel feed pump and tappet-drive cams for
the plunger.
A pump driving gear is mounted on the drive side of
the camshaft, and a governor weight on the opposite
side.
As the plunger rises, the fuel oil opens the delivery
valve and passes through the high pressure pipe to the
fuel injection nozzle.
When the control rack is connected to the governor
lever moves, the control sleeve turns the plunger.
This changes the point at which the helix (lead groove)
opens the port and thereby controls the amount of
fuel injected.
Fuel tank
3-2-1
1-2 Fuel injection p u m p specifications
Type
Specifications
4LHA Serit
YPES-AL
See separate
service data