Hyundai Sonata 1991 Shop Manual page 171

AUTOMATIC SPEED CONTROL (CRUISE)
CONTROL UNIT FUNCTIONS
Y27EGOA
1. SET (Fixed-speed control)
When, with the CRUISE switch set to ON, the SET switch is switched from ON to OFF while the vehicle is
being driven within the speed range in which speed settings are possible (approximately 40-137 km/h (25-85
mph)), the vehicle speed at. the moment the SET switch was switched from ON to OFF is memorized as the
"set vehicle speed", and thereafter the actuator is controlled so that f.ixed-speed driving at that speed is possible.
The figure below shows the timing charts.
-
J
. .
~
Control pulses
)
[Initial pulse
1\
(TRIM PULSE)
I III
\
I I I
Fixed-speed driving
Manua
ON
OFF
NO
OFF
SET switch
CRUISE switch
Manual driving I driving
Electromagnetic clutch ON
OFF
Actuator (motor) Stop
Deceleration
(reverse rotation)
Acceleration
(forward rotation
1) INITIAL PULSE
The initial pulse opens the throttle valve to a degree of opening which approximately corresponds to the
vehicle .speed. This pulse is output when the ASC system is set.
2) TRIM PULSE
The trim pulse is a control pulse for correcting the vehicle speed which is output is response to detected
speed errors.
The output pulse width is determined based upon the amount of deviation between the current vehicle speed
and the set vehicle speed, and upon throttle position.
2. COAST
Y27EHOA
During fixed-speed driving, while the SET switch is ON, the acuator's D.C. motor is caused to rotate to the
REL (release) side. The vehicle speed when the switch is switched OFF as deceleration continues is entered
in the memory, and is thereafter controlled as the fixed speed.
3. RESUME SPEED
Y27E.lOA
When (after the ASC system is canceled by the cancel conditions described in item 5 during fixed-speed driving)
the RESUME switch is switched from OFF to ON, while driving at a vehicle speed which is the low-speed limit
(approximately 40 km/h (25 mph) or higher, the vehicle speed memorized before cancelation of the ASC system
will be controlled as the fixed speed.
4. ACCELERATION
mEKOA
During fixed-speed driving or above the low-speed limit, while the RESUME switch is ON, the actuator's D.C
motor is caused to rotate to the PULL side. The vehicle speed when the switch is switched OFF as acceleration
continues is entered in the memory, and is thereafter controlled as the fixed speed.
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