Stage Di Nozzle (V3800Di-T-E3B, V3800Di-T-E3Cb, V3800Di- T-E3Bg - Kubota V3600-E3 Shop Manual

V3-E3B SERIES, V3-E3CB SERIES, V3-E3BG SERIES, WSM
[5] 2 STAGE DI NOZZLE (V3800DI-T-E3B, V3800DI-T-E3CB, V3800DI-T-
E3BG)
First opening pressure
The force of the high pressure fuel delivered by the injection pump acts to push the needle valve up. When this
force exceeds the set force of the first spring, the nozzle's needle valve pushes the first pushrod up and the valve
opens. (First opening pressure is represented by point E in the left hand figure, and point A in the right hand figure.)
Second opening pressure
When the first pushrod has been lifted through the pre-lift, it contacts the second pushrod. As the set force of the
second spring is acting on the second pushrod, the combined forces of both the first spring and the second spring then
act on the needle valve, which will not lift unless these forces are overcome.
When the high pressure fuel (ie, in-line pressure) overcomes the combined forces of the first and second springs,
the needle valve is again lifted and main injection can begin. (Second opening pressure is represented by point F in
the bottom left hand figure and B-C in the above figure.)
Exhaust and noise regulations are becoming
increasingly strict, particularly in regard to the reduction
of NOx (nitrogen oxides) and particulates.
The two-spring nozzle holder has been developed to
reduce NOx (nitrogen oxides) and particulates from
direct injection diesel engine exhaust.
Features
The two-spring nozzle holder limits needle valve lift at
initial valve opening to throttle the injection quantity.
Main injection occurs when the in-line pressure has
increased sufficiently to move the needle valve through
its full lift.
This gives the following features.
• Improved engine stability at low and intermediate
speeds.
• Decreased engine hunting and surge.
• Decreased noise at idling.
• Decreased idling speed because of improved engine
stability.
• Stabilized fuel injection characteristics from the
injection pump and nozzle system, and easier
matching of governor characteristics to engine
demand.
(1) Nozzle Holder Body
(2) 1st Stage Injection Pressure
Adjusting Shim
(3) First Spring
(4) Pressure Pin
(5) Spring Seat
(6) 2nd Stage Injection Pressure
Adjusting Shim
M-23
DIESEL ENGINE
(7) Second Spring
(8) Pre-lift Adjusting Spring Seat
(9) Chip-packing
(10) Max-lift Adjusting Washer
(11) Retaining Nut
(12) Nozzle
W1014568
A-B : First Spring's Set Force
B-C-D : Combined Force of
First and Second Springs
P1 : First Opening Pressure
P2 : Second Opening Pressure
L : Full Needle Valve Lift
l : Needle Valve Pre-lift
X1 : Cam Angle (°)
Y1 : Injection Rate (mm3/°)
X2 : Needle Valve Lift (mm)
Y2 : In-line Pressure
W1014795