Great Wall GW491QE, Руководство по обслуживанию

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EF.1-14
United฀Electronic฀engine฀management฀system-Analysis฀of฀function฀/principal฀/
failure฀for฀system฀parts฀&components
Performance฀data
R esistance value k
Tolerance of temperature 1 Tolerance of temperature 0 S.N.
Min. Max. Min. Max.
Temperature
6.฀Oxygen฀sensor฀LSH
(a)Function£ºto฀measure฀the฀oxygen฀content฀in฀exhausted฀gas฀from฀engine,฀and฀to฀determine฀a฀sufficient฀or฀insufficient฀combustion
of฀petrol฀and฀air.฀Based฀on฀such฀information,฀the฀electronic฀controller฀may฀perform฀a฀closed-loop฀control฀to฀reach฀an฀excessive ฀air
coefficient฀equal฀to฀1,฀and฀to฀assure฀Max.฀conversion฀efficiency฀of฀three฀contaminants฀(HC,฀CO฀and฀NOx)฀in฀exhausted฀gas฀by฀the
three-way฀catalytic฀converter.
1.
cables
2.disk฀ring
3.insulated฀bush
4.protective฀jacket
5.heating฀element
clamp฀connector
(b)Principal The฀sensing฀element฀is฀one฀ceramic฀pipe,฀whoseinner฀side
links฀ the฀ exhausted฀ gas,฀ and฀ outer฀ side฀ links฀ the฀ atmosphere.
When฀at฀a temperature฀of฀350 ,฀the฀sensing฀ceramic฀pipe฀will฀have฀the
characteristic฀of฀solid฀electrolyte,฀through฀which฀the฀density฀difference฀of
oxygen฀may฀be฀conversed฀into฀a฀difference฀of฀potential฀to฀produce฀a฀current
signal฀output.฀And฀a฀relatively฀dense฀gas฀mixture฀results฀in฀a฀large฀difference
of฀density฀for฀oxygen฀ion฀inside฀and฀outside฀the฀ceramic฀pipe,฀and฀a฀larg e
difference฀of฀potential฀as฀well฀that฀a฀large฀number฀of฀oxygen฀ions฀will฀move
from฀the฀inside฀to฀the฀outside,฀and฀the฀output฀voltage฀will฀be฀high close
to฀900mV ;฀And฀a฀relatively฀thin฀gas฀mixture฀results฀in฀a฀smaller฀difference
of฀density฀for฀oxygen฀ion฀inside฀and฀outside฀the฀ceramic฀pipe,฀and฀a฀smaller
difference฀of฀potential฀as฀well฀that฀a฀small฀number฀of฀oxygen฀ions฀will฀move
from฀the฀inside฀to฀the฀outside,฀and฀the฀output฀voltage฀will฀be฀low close฀to
100mV .
(c)Installation฀ position
on฀ the฀ front฀ end฀ of฀ exhaust฀ pipe.
(d)Mounting฀torque (40 60)N m
(e)Symptom inferior฀idle-speed,฀bad฀acceleration,฀tail฀gas฀out฀of฀limit,
large฀oil฀consumption,฀etc.
(f)Cause฀of฀general฀failures
Damp฀moisture฀content฀inside฀sensor,฀sharp฀change฀of฀temperature,฀rupture
of฀ probe.
Oxygen฀ sensor pisoning . Pb S ,
B r S i
(g)Precautions฀to฀maintenance During฀maintenance,฀it’s฀prohibited฀to
apply฀any฀cleaning฀liquid,฀oily฀liquid,฀or฀volatile฀solid฀onto฀oxygen฀sensor.
European฀Class-II
European฀Class-III
6.heating฀stick
7.contact฀washer
8.sensor฀seat
9.ceramic฀probe
10.protective฀tube
(h)Simple฀measurement฀method
after฀disconnection฀of฀joint ฀Have฀digital฀multimeter฀adjusted฀to฀the ohm position,฀and฀connect฀two฀pens฀with฀Pin฀1
white and฀Pin฀2 white of฀ sensor฀respectively;฀And฀the฀resistance฀value฀at฀normal฀temperature฀shall฀be฀1 6
.
after฀connection฀of฀joint When฀the฀working฀temperature฀of฀oxygen฀sensor฀reaches฀350 ฀while฀engine฀is฀running฀at฀idle-speed,
have฀digital฀multimeter฀adjusted฀to฀the฀DC฀voltage฀position,฀and฀connect฀two฀pens฀with฀Pin฀3 grey ฀and฀Pin฀4 black of
sensor฀respectively.฀And฀the฀voltage฀is฀subject฀to฀a฀quick฀fluctuation฀within฀0.1-0.9V.
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