Kubota EA330-E4 Series - Injection Pump

ENGINE
EA330-E4, WSM
1-M17
[2] INJECTION PUMP
A Bosch M type mini pump is used for the injection
pump. It is small, lightweight and easy to handle.
The plunger (4) with a left-hand lead reciprocates via
the tappet roller (3) by means of the camshaft fuel cam,
causing the fuel to be delivered into the injection nozzle.
The fuel in the fuel chamber is drawn into the
delivery chamber when the plunger lowers. When the
plunger rises, delivery valve (5) is pushed open to force
into the injection nozzle.
The control rack (2) is actuated by the governor, and
the control rack movement is transmitted to the control
sleeve (1). As a result, the plunger rotates to vary the
amount of fuel fed into the injection nozzle.
When the speed control lever is set to the stop
position, the fuel is not pressurized, and is not injected
since the feed hole meets with the control groove.
9Y1211018ENM0029US0
Fuel Pressure-feed Stroke to Injection Nozzle
1. Fuel Suction
The fuel fed into fuel chamber (2) by the action of the
fuel feed pump when plunger (1) is down is drawn into
delivery chamber (4) after passing through feed hole (3).
2. Fuel Pressure-feeding Commencement
When plunger (1) rises, the surface of the plunger
head blocks feed hole (3) and the pressure inside
delivery chamber (4) increases thereby raising delivery
valve (5) and fuel commences to be pressure-feed into
the nozzle.
3. During Fuel Pressure-feeding
The plunger continues to rise and pressure-feeding
of fuel continues.
4. Conclusion of Fuel Pressure-feeding
The plunger continues to rise even further and
control groove (6) on the outer periphery of the plunger
reaches the feed hole, fuel then passes from delivery
chamber (4) through the control groove and returns to
fuel chamber (2) after passing once again through feed
hole (3).
9Y1211018ENM0030US0
(1) Control Sleeve
(2) Control Rack
(3) Tappet Roller
(4) Plunger
(5) Delivery Valve
(6) Delivery Valve Holder
(7) Dumping Valve
(1) Plunger
(2) Fuel Chamber
(3) Feed Hole
(4) Delivery Chamber
(5) Delivery Valve
(6) Control Groove
KiSC issued 05, 2015 A