Bendix Commercial Vehicle Systems eTrac Automated Air Pressure Transfer System - Manual (Page 4)

4
EXH
SUP
SER
DEL
EXH
SUP
DEL
SUP
DEL
EXH
DEL
D
The leveling valve maintains equal pressure in
the drive and tag axle suspension air bags
DEL SUP EX H
Drive axle Tag axle
Air supply
Double check valve
Pressure protection valve
Solenoid valve
(OPEN)
Backfeed
valve
Limiting
valve
Delivery to the
drive axle air bag
suspension
Delivery to the tag axle
air bag suspension
SUP
“Dump” valve
LEVELING
VALVE
• The solenoid valve remains in the
OPEN position; this holds the relay
valve in the applied position.
• The delivery from the leveling
valve maintains the drive and tag
suspension air bags at the same
pressure. The delivery air travels
through the backfeed and limiting
valves to the drive axle, and through
the relay valve to the tag axle.
FIGURE 3 - BENDIX ® eTrac ™ SYSTEM NORMAL (“AUTOMATIC”) MODE
4. OPERATION
4.1 Automatic Mode: Normal Mode.
Figure 3 shows the normal system position where the leveling valve controls the delivery of air to the rear axle air
suspension bags.