(2)entering air temperature sensor: inspect the entering air temperature
。
(
3
)
air throttle position sensor: inspect air throttle open degree.
(4) idle speed valve: control engine idle speed.
Idle speed controlling valve
1. Idle speed controlling valve function
a. can keep the idle speed in the previous decided rotate speed;
b.can auto improving the idle speed under the accelerator pedal relaxing situation, in order to use A/C.
c. can compensating when urgent acceleration ,deceleration in order to transit rotation speed smoothly.
2
.
idle speed control valve structure
Like picture showing on the right side, make up of servomotor and rotary valve.
3. idle speed control valve working principle
Step motor is a minisize motor, which is made up of circuited steel stators and one rotor. Each steel stator
wrapped by coil: rotor is a permanent magnet; the centre of it is a nut. All the stator coils always electrify. If only
change one coil electricity direction, rotor will change a angle. When each stator coil change electricity in a proper
order, then the rotation direction of rotor will be reversed. The nut connecting with the rotator centre drives one
screw mandrel. Because screw rod is designed for not running, so its only can move on the axes direction, also be
called straight shaft. The head of screw rod is choke plug, so the choke plug can retract and hang out so that
increase or decrease the induction trunk section surface which besides the idle speed actuator until block it.
stitch A connect with stitch NO.ECU65
stitch B connect with stitch NO>ECU66
Stitch C connect with stitch NO>ECU67.
4
.
Technique characteristic parameters
5. Symptom and judgments
Symptom: idle speed too high, idle speed flame out.
Minor failure causation: bypass air access blocked by dust ,fuel steam accumulate, let the step motor idle
speed adjust abnormally.
值
SCOPE
least typical most
unit
Resistance of every coil at 25 degree
47.7
53
58.3
Ω
Resistance of every coil in the range
of working temperature
35(-40
o
C) 95(+125
o
C)
Ω
Inductance of every coil to the
1000HZ at 25 degree
26.8 33
.
5 40.2 mH
normal working voltage
7.5
12.0
V
possibility working voltage
3.5
14.0
V
stepsize of step motor rotor
15
Pressure of bypass passage opening
60
kPa
The most axial force made by air
pressure difference
6.28 N