Kubota D1402-B - Quantity Control of Fuel Injection

KiSC issued 09, 2007 A

(A) Pressurization of Fuel
(b)
(a)
(c)
(d)
(f )
(e)
Fig. 1
Fig. 2
How it works:
1 ) When the pl u nger is at the bottom of its stroke, f uel from
the f uel cha mber enters the del ivery chamber through the
f eed hole
( F ig. 1)
2) As the ca mshaf t rotates, pl u nger moves u pward, the
stroke of
f uel pressu ri zation begi ns. ( Fig. 2)
3) As the pl u nger moves u p, the pressu re i ncreases u nti l it
opens the del ivery va
l ue a nd sends the pressu ri zed f uel to
i nject ion nozzle th rough the i njection pi pe. ( Fig. 3)
4) Send i ng of f uel stops as soon as the control groove meets
the
f eed hol e. Fuel f l ows out th rough the pl u nger's center
hol e, control groove and feed hole, then backs to the f uel
cha m ber. As
a resu lt, the pressu re fa l ls a nd the stroke is
com pleted.
( F i g. 4)
0011F044
Fig. 3
Fig. 4
(A) Pressurization of fuel
(a) Delivery Chamber
(b) Delivery Valve
(c) Feed Hole
(d) Fuel Chamber
(e) Plunger
(f ) Control Groove
(A) Injection Control
Fig. 1
Fig. 2
t
(e)
Quantity control of fuel injection
1) No fuel
The f eed hole meets the control-groove before bei ng cl osed
by the pl u nger top. Th erefore, no f uel is pressu ri zed a nd
i njected. ( Fig. 1)
2) Partial fuel
Pl u nger rotates a certa i n a mou nt when the control rack is
moved
i n the direction of the a r row. Ef f ective stroke A
mea ns the d ista nce wh ich the f eed hole is closed by the pl u n-
ger before meeti ng the control groove on th e pl u nger. There-
fore,
f uel is i njected as mu ch as the amou nt of effective
stroke. (Fig.
2)
3) Maxim u m fuel
As the control rack moves the greatest possi ble a mou nt i n
the d
i rection of the a rrow, the eff ective stroke A is max i-
mu m a nd the ma x
i m u m a mou nt of f uel is i njected.( Fig. 3)
I