Dodge Sprinter 2006 Manual page 1683

VA
1 - HIGH PRESSURE FUEL PUMP
2 - FUEL FROM LOW PRESSURE PUMP
3 - FUEL FILTER
4 - LOW PRESSURE FUEL PUMP
5 - FUEL TANK
6 - RETURN FUEL
7 - HIGH PRESSURE FUEL FROM HIGH PRESSURE PUMP
OPERA TION
Th er e a r e sever a l m odes of oper a t ion for t h e Com -
m on Ra il Diesel In ject ion Syst em .
P r e-in ject ion Th e pu r pose of t h e pr e-in ject ion fu n c-
t ion is t o r edu ce n oise a n d pollu t a n t s. Th e coola n t
t em per a t u r e, ch a r ge a ir t em per a t u r e a n d a t m o-
sph er ic pr essu r e a r e u se t o cor r ect t h e qu a n t it y of
pilot in ject ion . Th e qu a n t it y of pilot in ject ion n ow
det er m in ed is dedu ct ed fr om t h e qu a n t it y of m a in
in ject ion in or der t o est a blish wh et h er su fficien t
qu a n t it y is a va ila ble for t h e followin g m a in in ject ion .
Th e r a il pr essu r e is ch osen su fficien t ly h igh so t h a t
a m in im u m qu a n t it y is in ject ed. If t h e qu a n t it y of
m a in in ject ion is t oo sm a ll t h e pilot in ject ion is
swit ch ed off by t h e E CM.
Th e st a r t of a ct u a t ion of pilot in ject ion is ca lcu -
la t ed depen den t on oper a t in g poin t , t h e followin g
da t a bein g t a ken in t o a ccou n t :
Sh u t t in g Off P r e-in ject ion Th e pr e-in ject ion is sh u t
off wh en :
• Th e m om en t of pr e-in ject ion is exceeded
• E n gin e speed t oo h igh
• P r e-in ject ed qu a n t it y t oo low
• Ma in in ject ed qu a n t it y t oo low
Fig. 1 FUEL SUPPLY
8 - FUEL INJECTOR
9 - HIGH PRESSURE FUEL FROM HIGH PRESSURE PUMP
10 - FUEL PRESSURE SOLENOID
11- FUEL RAIL
12 - FUEL RAIL PRESSURE SENSOR
13 - FUEL QUANTITY CONTROL VALVE
14 - FUEL TEMPERATURE VALVE
• In su fficien t fu el r a il pr essu r e
• E n gin e is swit ch ed off
Ca lcu la t in g P r e-in ject ion Qu a n t it y Th e pr e-in jec-
t ion qu a n t it y is ca lcu la t ed on t h e ba sis of:
• E n gin e speed
• At m osph er ic pr essu r e
• Coola n t t em per a t u r e
• Boost a ir t em per a t u r e
• F u el r a il pr essu r e
Ma in In ject ion Th e pu r pose of m a in in ject ion fu n c-
t ion is t o en a ble t h e in ject ion t im e a n d in ject ion
per iod ca lcu la t ed by t h e E CM. Th e in ject ion qu a n t it y
r equ ir ed by t h e en gin e is divided in t o t h e per-in jec-
t ion a n d m a in in ject ion qu a n t it y. If t h e m a in in jec-
t ion qu a n t it y com pu t ed by t h e E CM is t oo sm a ll, n o
pr e-in ject ion t a kes pla ce.
Start of Actuation
Th e st a r t of a ct u a t ion of m a in in ject ion is depen -
den t on en gin e speed a n d qu a n t it y. In a ddit ion , it is
cor r ect ed depen din g on t h e followin g va lu es:
• Coola n t t em per a t u r e
• Boost a ir t em per a t u r e
• At m osph er ic pr essu r e
• P r e-in ject ion cor r ect ed YE S/NO
FUEL DELIVERY 14 - 7