BENDIX BW2598 데이터 시트

See Figure 2.  The ATR-6

™

 Antilock Traction Relay valve is 

a service relay valve fi tted with a modifi ed cover containing 
a Control Solenoid.  Under normal operating conditions the 
Control Shuttle, a small piston within the traction solenoid, 
remains in its rest position, held by spring pressure. 

This document will describe the use of the ATR-6

™

 valve  

when used during a traction control event, although this 
is only one role for which this valve is used.  Advanced 
Bendix ABS systems also use this valve to help supply 
specifi c braking delivery for ABS events at a wider range of 
speeds than typical traction control events occur, however 
the process of energizing the solenoid and delivery of air 
is the same.

See Figure 3.  During normal braking, as the driver applies 
force to the brake pedal, air pressure is delivered from the 
brake pedal to the relay valve control port.  The air pressure 
passes into the valve, past the Control Shuttle, and moves 
the relay valve piston down.  The piston pushes down 
and contacts the exhaust seat of the inner (or ‘exhaust’) 
portion of the inlet/exhaust valve, sealing off the exhaust 
passage.  As the piston moves further down, the outer (or 
‘inlet’) portion of the inlet/exhaust valve moves off its seat, 
permitting supply air from the reservoir to fl ow past the open 
inlet valve, and into the service brake chambers. 

BRAKE PEDAL

RESERVOIR

DELIVERY PORT 

VALVE EXHAUST 

RELAY VALVE 

PISTON

CONTROL

SOLENOID

CONTROL PORT

SUPPLY PORT

ANTILOCK

MODULATOR

VALVE

BRAKE

CHAMBER

TONE RING

WHEEL SPEED 

SENSOR

Control Shuttle. The small 

piston (shown in its normal 

rest position). The  arrow 

indicates spring force 

holding it in position.

The driver applies 

the brakes. The 

piston in the relay 

valve moves 

down allowing 

the waiting air 

pressure to pass 

to the brake 

chambers 

RESERVOIR

BRAKE

CHAMBER

See Figure 4.  The air pressure being delivered by the open 
inlet valve also is effective on the bottom area of the relay 
piston.  When air pressure beneath the piston equals the 
service air pressure above, the piston lifts slightly and the 
inlet spring returns the inlet valve to its seat.  The exhaust 
remains closed as the service line pressure balances the 
delivery pressure.  As delivered air pressure is changed, 
the valve reacts instantly to the change, holding the brake 
application at that level.

INLET / 

EXHAUST 

VALVE