Specifications

CONFIDENTIAL
Bendix Commercial Vehicle Systems LLC
Elyria, OH 44036
PRODUCT SPECIFICATION - BW-283-PR
SPEC. BW-283-PR
73 SHEETS
SHEET NO. 26
3.4 BR9235 Modulator Relay Valve (MRV)
The BR9235 Modulator Relay Valve (MRV) is required when additional MRV’s are
needed for multi-channel TABS brake systems (e.g. 2S/2M, 4S/3M ABS configurations).
The BR9235 MRV is controlled by the TABS6 ECU to modify driver applied air pressure
to the service brakes during ABS activation. The ABS modulator-valve is an electro-
pneumatic control valve and is the last valve that air passes through on the way to the
brake chambers. The normally open hold solenoid and normally closed exhaust solenoid
are activated to precisely modify the brake pressure on command.
During normal braking, the BR9235 MRV functions as a standard relay valve. As brakes
are applied or released by the driver, the control signal from the tractor foot valve causes
the BR9235 MRV to apply proportional pressure to the trailer brake chambers.
Figure 17: BR9235 Modulator Relay Valve (MRV)
3.4.1 BR9235 MRV Specifications
3.4.1.1 Solenoid Characteristics
The relay valve solenoids meet the following characteristics (at 75 °F /
25 °C):
Min Typ Max Value
Voltage range 6.8 12 15.7 V
Resistance 5.0 5.5 7.5 Ohm
Table 7: BR9235 MRV Solenoid Characteristics
3/8”NPT Control Port
w/ Integral Filter
3/4” NPT Supply Port
(Hidden)
Four (4) 3/8” NPT Delivery Port
(To Brake Chambers)
3-Pin Modulator
Solenoid Connector
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