Chrysler laser 1990 Technical Information Manual page 161

Servo Control
Servo control includes feedback control and position
the value differs from the target idle speed, the unit
drives the stepper motor to adjust actual speed to
Feedback Control
While the engine runs at idle speed, the stepper
motor is activated to keep the engine speed at the
preset target idle speed by controlling the bypass air
volume.
The target idle speed that is optimum for each
operating condition (including air conditioner switch
ON/OFF) has been preset. This engine speed
feedback control is provided under stabilized idling
conditions and not when any of the following
conditions occur.
When the vehicle is moving at 2.5 km/h (1.6
l
mph) or more.
Coolant temperature
Difference between the target
actual
and idle speed fpm
Time sec.
FUEL SYSTEM - Idle Speed Control
Air conditioner switch
Servo Drive Steps
speeds, the servo is activated the number of angular steps
corresponding to the difference, thereby extending or
adjusts the actual idle speed to the target value.
The sewo drive steps during idle speed feedback Control
the target value. In position control, the idle speed
control is adjusted to the target position to cope
with conditioner and other load changes. Position
air
and decelerating.
l When the idle switch is turned from OFF to
and while the idle switch is in the OFF position.
l When the air conditioner switch is turned from
l
turned from ON to OFF, or vice versa.
When the ignition switch is turned from ST to
l
While the dash pot control is in operation.
l
When the inhibitor switch is switched from "N"
l
range to "D" range or vice versa.
control servo
I-
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Stepper motor 7
I
I
. I.
Engine speed
ON,
I
Engine
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