General Description And System; Operation; Cruise Control System Operation . 9U-19; Cruise Control Actuator 9U-19 - Daewoo Nubira User Manual

GENERAL DESCRIPTION
AND SYSTEM OPERATION
CRUISE CONTROL SYSTEM

OPERATION

The cruise control system automatically maintains a ve-
hicle speed set by the driver. When the cruise control sys-
tem is activated, speed is maintained or increased by
means of an electronically controlled cable attached to the
accelerator assembly. If the vehicle must be slowed to
maintain the speed set by the driver, the cruise control sys-
tem allows the throttle return spring to close the throttle.
If driving conditions require sudden acceleration after the
cruise control has been set, speed can be increased in the
normal manner by manually pressing the accelerator. The
cruise control is disengaged if the brakes (or the clutch,
with a manual transaxle) are applied.
The minimum speed for setting the cruise control is 38.6
km/h (24 mph). When cruise control is operating, the
CRUISE indicator lamp is turned ON in the instrument
cluster.
The cruise control system is capable of monitoring internal
software and hardware faults as well as external faults in
the connectors and the wire harness. If a fault is detected,
cruise control is stopped immediately, and the program
logic and hardware logic both prevent the cruise control
from opening the throttle.
The cruise control will function in temperatures ranging
from –40°C (–40°F) to 85°C (185°F). Maximum tempera-
ture could cause the regulation properties to be out of tol-
erance, but the safety shutdown is still operational under
maximum temperature conditions. If high temperature in-
terferes with the cruise control operation, the actuator
electromagnetic clutch will open, and the throttle return
spring will close the throttle unless the accelerator pedal
is pressed.
CRUISE CONTROL ACTUATOR
The cruise control actuator is a single–component sys-
tem. The electronic controls are combined in one housing
with the mechanical components. The actuator is
mounted in the passenger compartment..
The mechanical components of the cruise control actuator
are listed below:
DAEWOO V–121 BL4
CRUISE CONRTOL SYSTEM 9U – 19
S
Permanent field DC motor.
S
Single stage belt transfer gearing.
S
Spindle drive.
S
Electromagnetic clutch.
S
Clutch plate with cable attachment.
S
End switches.
S
Plastic housing with noise reduction cover.
S
Damping unit for clutch plate slap.
The electronics of the cruise control system include the
following items:
S
A microprocessor which controls speed regulation
and monitors input signals.
S
A clutch activation circuit which energizes the
clutch magnet in order to couple the DC motor to
the control cable.
S
A driver circuit which activates the DC motor in a
clockwise or counterclockwise direction.
S
A control unit for lamp activation.
The parts of the cruise control actuator are not service-
able. The entire actuator must be replaced if there is an
electronic or mechanical defect in one of the systems.

MAIN SWITCH

The cruise control main switch is on the center of the in-
strument panel.
Cruise control can only be set with the lever switch when
the main switch is ON.
The main switch has an indicator which turns ON when the
main switch is pressed. If the switch is pressed again, the
indicator and the switch turn OFF.
The main switch also is connected to the instrument illumi-
nation system, so the dimmer switch controls switch illumi-
nation when the headlamps or parking lamps are ON.

LEVER SWITCH

After the main switch is turned ON and the neutral position
of the lever switch is detected by the cruise control actua-
tor, the following operations can be performed by using the
cruise control lever switch:
Set – If the cruise control is ON and the minimum speed
is 38.6 km/h (24 mph) but not more than 155 km/h (96
mph), the target speed can be set by selecting the SET
function for 10 to 300 milliseconds. If SET is selected for
more than 300 milliseconds, the cruise will be activated in
the COAST function. If the accelerator is pressed by the
driver after the cruise control has been set, the previous
target speed will be maintained when the accelerator is re-
leased. If the accelerator is pressed by the driver until the
actual speed is more than 35 km/h (22 mph) over the tar-
get speed, or until the vehicle exceeds 160 km/h (99 mph),
the cruise control will disengage.
Coast – If a target speed has been set and COAST is se-
lected for at least 300 milliseconds, the throttle is allowed
to return to idle and the vehicle will coast. When the
COAST switch is released, the current speed will be main-
tained as the new target speed. If the vehicle speed drops