TECHNICALANDCONSUMERINFORMATION
Sequentialmultiportfuelin-
jectionsystem
injectors,whereitisavailabletoflowoutof
havesensorsthattellaboutsuchconditions.
Themostimportantoftheseisthecrankangle
sensor.Thecamshaftpositionsensortellsthe
ECM the engine speed and the positions of
thepistonsunderallconditions.
theinjectornozzlesandintotheintakeports
whentheinjectorsareopenedelectricallyby
signalsfromtheECM.
Your INFINITI engine uses a separate fuel
injector for each cylinder. These are placed
into the intake ports, so that they can spray
atomized fuel under pressure into the intake
air stream. These injectors are controlled
Byallowingmoreorlessfueltoreturntothe
tank,thefuelpressureregulatormaintainsthe
pressureattheinjectorsat34psi(2.4kg/cm2,
Controlofcombustiontem-
perature
‘‘sequentially’’,
whichmeansthattheyoperate
235kPa)abovemanifoldpressure.
Oxidesofnitrogen,inanumberofchemical
variations,areamongthemajorcomponents
ofphotochemicalairpollution.Thesenitrogen
oxide compounds are formed in the engine
whenthecombustiontemperaturesarehigher
than about 2,000°F (1,093°C). One way to
decrease nitrogen oxide formation in the
engine, then, is to cool the temperature of
combustionslightly.Thisisdonebyallowing
asmallamountofburned,andthereforeinert,
exhaust gases to recirculate back into the
engine intake manifold where they can be
drawnintothecylinders.
ineachcylinderaccordingtothefiringorder.
Each injector opens to spray its carefully
meteredamountoffueljustbeforetheintake
valveofthecylinderopens.
ThatallowstheECMtoadjusttheflowoffuel
into the engine simply by controlling the
amount of time the injectors stay open. The
longer the injectors are held open, in milli-
seconds,themorefuelflow.
Constantpressure
Ignitiontimingcontrol
Fuelinjectoroperationdependsuponasupply
offuelthatisalwaysmaintainedataconstant
pressure in relation to the pressure in the
engine intake manifold. Under pressure, the
fueltravelsthroughtheline,throughalarge
and efficient fuel filter mounted under the
hood, and into a ‘‘fuel rail’’ which feeds the
injectors. Fuel flows into the bases of the
For best efficiency, ignition timing must be
dynamic, that is it must change depending
upontheengineoperatingconditions.Itmust
respondtoengineload,RPMchanges,engine
temperaturechanges,altitude,andsoon.For
precisely correct, automatic, adjustments in
ignition timing to take place, the ECM must
10-5
| Categories | Infiniti Manuals, Infiniti QX Manuals |
|---|---|
| Document Type | Free Auto PDF Owners Manual Download |
| Tags | Infiniti QX4 3.3 |
| Model Year | 1998 |
| Download File |
|
| Document File Type | |
| Publisher | infiniti.com |
| Wikipedia's Page | Infiniti QX4 |
| Copyright | Attribution Non-commercial |
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Was looking for a way to disable the passenger airbag so I could have my dog beside me while traveling but it does not seem possible.