BENDIX SD-13-4793 Manuel D’Utilisation
5
ANTILOCK EXHAUST (FIGURE 7)
When wheel lock is detected, or imminent, the antilock
controller simultaneously energizes both the supply and
exhaust solenoids in the modulator. Energizing the supply
solenoid causes its exhaust to close and inlet to open.
With the inlet of the supply solenoid open, application
air is permitted to fl ow to the control side of the supply
diaphragm. Air pressure acting on the supply diaphragm
causes it to close the supply and prevent further delivery
of air to the brake chamber.
controller simultaneously energizes both the supply and
exhaust solenoids in the modulator. Energizing the supply
solenoid causes its exhaust to close and inlet to open.
With the inlet of the supply solenoid open, application
air is permitted to fl ow to the control side of the supply
diaphragm. Air pressure acting on the supply diaphragm
causes it to close the supply and prevent further delivery
of air to the brake chamber.
Energizing the exhaust solenoid closes its inlet and
opens its exhaust. By closing the exhaust solenoid inlet,
application air is prevented from fl owing to the control side
of the exhaust diaphragm. Air pressure, which was present
on the control side of the exhaust diaphragm fl ows out the
exhaust port of the modulator. With control air pressure
removed from the exhaust diaphragm, brake application
air forces the exhaust diaphragm to unseat which allows
it to fl ow out the modulator exhaust port. The modulator
will remain in the antilock exhaust mode until the antilock
controller senses that wheel speed has increased. The
modulator can enter the antilock hold or re-apply mode
from the antilock exhaust mode.
opens its exhaust. By closing the exhaust solenoid inlet,
application air is prevented from fl owing to the control side
of the exhaust diaphragm. Air pressure, which was present
on the control side of the exhaust diaphragm fl ows out the
exhaust port of the modulator. With control air pressure
removed from the exhaust diaphragm, brake application
air forces the exhaust diaphragm to unseat which allows
it to fl ow out the modulator exhaust port. The modulator
will remain in the antilock exhaust mode until the antilock
controller senses that wheel speed has increased. The
modulator can enter the antilock hold or re-apply mode
from the antilock exhaust mode.
ANTILOCK HOLD
The antilock controller will place the modulator in the
hold position when it senses that the correct wheel speed
(braking force) has been attained. The antilock controller
will also place the modulator in the hold position, prior
to entering the re-apply, when it detects recovery from
a locked wheel condition. In this mode of operation the
modulator supply solenoid remains energized while the
exhaust solenoid is de-energized. De-energizing the
exhaust solenoid opens its inlet and closes its exhaust.
Opening the exhaust solenoid inlet, allows application air to
fl ow to the control side of the exhaust diaphragm which then
seals the exhaust passage. With the exhaust diaphragm
seated, further exhaust of brake chamber air pressure is
prevented. Because the supply solenoid remains energized
the supply diaphragm remains seated, thus preventing
application air from fl owing to the delivery port and out to
the brake chamber. The modulator can enter the antilock
exhaust or re-apply mode from the antilock hold mode.
hold position when it senses that the correct wheel speed
(braking force) has been attained. The antilock controller
will also place the modulator in the hold position, prior
to entering the re-apply, when it detects recovery from
a locked wheel condition. In this mode of operation the
modulator supply solenoid remains energized while the
exhaust solenoid is de-energized. De-energizing the
exhaust solenoid opens its inlet and closes its exhaust.
Opening the exhaust solenoid inlet, allows application air to
fl ow to the control side of the exhaust diaphragm which then
seals the exhaust passage. With the exhaust diaphragm
seated, further exhaust of brake chamber air pressure is
prevented. Because the supply solenoid remains energized
the supply diaphragm remains seated, thus preventing
application air from fl owing to the delivery port and out to
the brake chamber. The modulator can enter the antilock
exhaust or re-apply mode from the antilock hold mode.
FIGURE 6 - M-21
™
, M-22
™
MODULATOR NON-ANTILOCK EXHAUST OF SERVICE BRAKES (RAPID)
BRAKE VALVE
SPRING
SUPPLY
DIAPHRAGM
SUPPLY
SOLENOID
SPRING
EXHAUST
DIAPHRAGM
EXHAUST
SOLENOID
BRAKE
CHAMBER
EXHAUST PORT