Great Wall GW491QE, Service Manual

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EF.1-12
United฀Electronic฀engine฀management฀system-Analysis฀of฀function฀/principal฀/
failure฀for฀system฀parts฀&components
(h)฀Technical฀&characteristic฀parameter
Limit฀data
M easurement Value U nit
M echanic rotation angle between two extreme positions D egree
Available electrical rotating angle between two extreme positions D egree
A llowable current on sliding contact arm
Storage temperature
A llowable vibration acceleration
Performance฀data
M easurement V alue
M in. T y pical M ax .
U nit
T otal resistance P in 1-2
P rotection resistance on sliding contact arm ( w hen
sliding contact arm
is at zero position P in 2-3)
O peration temperature
S upply voltage
V oltage ratio on right ex treme position
V oltage ratio on lef t ex treme position
I ncrement rate of U p/U s
f or the rotation angle of throttle valv e
degree
W eight
European฀Class-II
4.฀Knock฀sensor฀KS
(a)Function:this฀sensor฀is฀used฀to฀provide฀the฀electronic฀controller฀ECU
with฀engine฀knock฀฀information฀for฀a฀knock฀control฀purpose.
(b)Principal Being฀one฀type฀of฀vibration฀acceleration฀sensor,฀the฀knock
sensor฀is฀installed฀on฀the฀engine฀body;฀Its฀sensing฀element฀is฀of฀one
piezoelectric฀crystal,฀to฀which฀the฀vibration฀on฀engine฀body฀may฀be฀transmited
via฀mass฀block฀inside฀the฀sensor.฀Under฀the฀vibration฀stress฀of฀mass฀block,฀a
voltage฀will฀be฀produced฀on฀two฀pole฀faces฀of฀piezoelectric฀crystal฀to฀converse
the฀vibration฀signal฀into฀voltage฀signal
(d)Mounting฀torque
(e)Symptom Bad฀acceleration,฀etc.
(f)Cause฀of฀general฀failur
The฀sensor฀might฀be฀corroded฀when฀contacting
with฀various฀liquids฀for฀long฀term฀period,฀such฀as฀machine-oil,฀cooling-fluid,
braking-fluid,฀water,฀etc.
Precautions฀to฀maintenance The฀sensor฀must฀have฀its฀metal฀surface฀closely
contacted฀with฀the฀engine฀body,฀and฀any฀type฀of฀washer฀is฀unallowable฀for
use฀during฀installation.฀During฀the฀signal฀cable฀pavement฀for฀sensor,฀it’s
noted฀that฀do฀not฀allow฀any฀syntony฀produced฀on฀signal฀cable฀to฀avoid
rupture.฀Always฀avoid฀the฀connection฀of฀high-voltage฀current฀between฀Pin฀1
and฀Pin฀2฀of฀sensor,฀otherwise,฀piezoelectric฀elements฀will฀be฀damaged.
Simple฀measurement฀method after฀disconnection฀of฀joint£©Have฀digital
multimeter฀adjusted฀with฀Pin฀1฀and฀Pin3฀respectively.฀And฀the฀resistance
value฀at฀roomtemperatureshall฀be฀greaterthan1M¦ ¸ Have฀digital฀multimeter
adjusted฀to฀the฀฀millivolt฀position,฀and฀use฀a฀small฀hammer฀to฀gently฀knock
on฀the฀area฀nearby฀the฀knock฀sensor,฀and฀a฀voltage฀signal฀output฀will฀be
produced.
European฀Class-III
1.shock฀block
2.exterior฀cover
3.piezoelectric
ceramic฀body
4.contact฀head
5.electrical฀plug
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