Kubota EA330-E4 Series Workshop Manual page 51

EA330-E4, WSM
Regulating Fuel Injection
1. No Fuel Delivery....Engine Stopped
When the control rack (5) is set at the engine stop
position, the plunger (2) is rotated to a position where the
vertical slot (6) in the plunger (2 aligns with the feed hole
(4). Since the vertical slot prevents the feed hole from
being covered, pressure in the delivery chamber (7)
cannot build up. Therefore, no fuel can be forced to the
injection nozzle.
2. Fuel Injection....Small to Medium
When the plunger rotates in the direction of the arrow
by the action of the control rack (as shown in the figure)
and after the head-section of plunger (2) closes off feed
hole (4), the quantity of fuel in the effective stroke "A"
(the section of strode up until control groove (3) reaches
the feed hole) is fed to the nozzle and injected.
3. Fuel Injection....Maximum
When the control rack has moved maximum
distance in the direction of the arrow, effective stroke "B"
of the plunger is at its maximum, consequently, fuel
injection is also at maximum.
(1) Control Sleeve
(2) Plunger
(3) Control Groove
(4) Feed Hole
(5) Control Rack
1) Pump Element
The pump element (1) consists of the plunger (3) and
the cylinder (2).
super-precision finished to maintain a sufficient injection
pressure at low speeds.
The driving face (8) goes inside the control sleeve,
and moves the control rack. As a result, the plunger (3)
is turned and increases or decreases the fuel injection
rate accordingly.
As explained earlier, the plunger is provided with a
control groove (7), a notch (5) for stopping and a speed
advance lead (6). The control groove is a left-hand lead.
(1) Pump Element
(2) Cylinder
(3) Plunger
(4) Feed Hole
1-M18
ENGINE
(6) Vertical Rack
(7) Delivery Chamber
A: Effective Stroke (Small)
B: Effective Stroke (Large)
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Their sliding surfaces
(5) Notch for Stopping
(6) Speed Advance Lead
(7) Control Groove
(8) Driving Face
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KiSC issued 05, 2015 A
are