Switching Off Main Injection
Main injection is swit ched off wh en:
• Engine speed is too h igh >4700 - 4800 rpm
• Ma in in jection quantit y too low
• Low fuel pressure in fuel ra il
• Engine off
• Externa l qua ntity control
• Deceler ation mode
Calculating Main Injection
The qu antity of main injection is calculated by:
• Engine speed
• Atmospher ic pressure
• Coolant temperatur e
• Boost a ir temper ature
• Fuel rail pressure
• Boost pressu re
Period of Actuation
For calculating the period of actuation of the m ain
injection it is necessa ry to know whet her a pre-injec-
tion has occurr ed or not.
The coolant t empera ture, charge air temper ature
and th e atmosph eric pr essu re ar e used for cor recting
the main injection qu antity. If main injection quan-
tity is less tha n a minim um qua ntity which is depen-
dent on fuel rail pr essu re, no preinjection takes
place. In this case, only main injection is per formed.
If th e qu antity is th en still below th e minim um
quan tity, neither ma in injection or pre-injection takes
place (deceleration m ode).
Deceleration Mode
The pur pose of the deceleration mode is to inter-
rupt th e operation of the injector s. The ECM det er-
mines th e accelera tor pedal position from a su pplied
signa l an d it determines th e engin e speed by the
crank sensor. In th e overrun and with the en gin e
speed above 1600, with t he accelerator pedal no
pr essed, the inject ors ar e no longer act uat ed and the
fuel rail pressu re is lowered by t he pressu re regula-
tor valve.
Full Load Injected Quantity
The purpose of the full loa d in ject ed qu antity is to
minimize th e forma tion of smoke. Th e ECM limits
the fuel ra il pr essu re when the engine is oper ating at
full load by wa y of the qu antity con trol valve, and
quan tity of fu el injected by th e injector s. th is mini-
mizes the formation of smoke when accelera tin g and
dr iving a t con st ant speeds. If a fault occur s at the
boost pressur e control, full load injected quantit y is
reduced.
Limiting Maximum Engine Speed
The ECM det ermines the engine speed based on
the signal supplied by th e crankshaft sen sor and lim-
its this by interru pt ing t he oper ation of the fuel
injector s.
Fuel Quantity Control
The fu el qu antity is contr olled separ ately for ea ch
cylinder by the ECM in lin e with the fir ing order.The
ECM detect s th e operating state which exist s at the
engine by means of the sensors. In or der adapt th e
quan tity injected, either t he fuel ra il pressu re can be
adju st ed by th e fuel solenoid a nd quantit y con trol
valve or the actuat ion t ime of th e solenoid valves in
the injector s
Boiling Protection
In or der t o protect a gainst ther mal over load a nd
alon g with criteria progra mmed in th e ECM, the
injection quantity is reduced a s a funct ion of t he cool-
ant tem perat ure and veh icle speed. If t he coolant
temper ature sensor fails the oil t empera ture signal
from the oil sensor is used a s a suitable valu e.
Fuel Tank Protection
The fuel rail pr essu re is lowered in order to pr otect
the fu el tank from overheating. The fuel tempera ture
sensor measures the t empera ture of th e fu el bein g
su pplied from th e tan k, in the high pressu re fla nge.
If th e fuel is too war m the fuel rail pressure is fur-
ther r edu ced by t he quantity contr ol va lve.
STAN DARD PROCEDU RE
STANDARD PROCEDURE - DRAINING FUEL
TANK - DIESEL
(1) Position a dra in hose int o the fuel fill openin g.
(2) Drain fuel t ank usin g an approved diesel fuel
dr aining station.
FUEL CONTAMINATION
If a diesel engine’s fuel supply ha s been contami-
nated with gasoline, the following pr ocedu re mu st be
followed:
(1) Remove all fuel from th e fuel ta nk. (Refer t o 14
- F UEL SYSTEM/FUEL DE LIVERY - STANDARD
PROCE DURE -DRAINING F UEL TANK) Use an
appropriate fuel contain er. Dispose of th e contami-
nated fu el using t he proper procedu res.
CAUTION: Dispose of petroleum based products in
a manner consistent with all applicable Local, State,
Federal, and Provincial regulations.
(2) Remove and clea n fuel tan k. (Refer to 14 -
FUE L SYSTEM/FUEL DE LIVERY/FUEL TANK -
REMOVAL)
(3) In st all the fu el tan k. (Refer to 14 - FUEL SYS-
TEM/FUEL DE LIVERY/FUEL TANK - INSTALLA-
TION )
14 - 8 FUEL DELIVERY VA
To Next Page
Loading...
