Brake System - BPW ECO Tronic EBS Operating And Installation Instructions

5 Installation and Operating Instructions

5.1 Brake system

Trailer air braking system
Twin-circuit braking system as per Directive
71/320/EEC
When the red supply line is connected, on automatic coupling
heads in tractor units the valve in the coupling head opens.
The compressed air now fl ows through the line fi lter to the
energy infl ow 1 of the Trailer Control Module (TrCM).
When the system is fi lled the fi rst time and is free of pressure,
the compressed air fl ows from the TrCM to the reservoir 1-2
and disengages the parking brake via the energy outfl ow 22 of
the TrCM when the red button (disengaging valve) is pressed.
This is why the yellow brake line should always be attached
fi rst when hitching up, ensuring the service brake in the trailer
is operated when the brake is applied in the tractor.
If there is no pressure acting on the yellow line, then the spring
brakes are bled via the quick release valve integrated in the EBS
and the parking brake is thus activated, when the red button of
the TrCM is pulled.
Actuation of the service brake
When the service brake in the tractor unit is actuated, the trailer
control valve admits compressed air to the yellow service line.
The braking pressure is then passed on to control port 4 of
the TrCM.
The TrCM now steers compressed air through the energy outfl ow
21 to the downstream EBS.
The ALB system integrated in the EBS regulates the pressure
according to the load status so that pressure appropriate to the
load can be guided to the brake cylinders of the braked axles.
Compressed air brake system
Coupling head (yellow)
Coupling head (red)
EBS cable
ISO 7638 1
ISO 1185 or
ISO 12098 Trailer lighting
Fig. 91
54
Additional connections
e.g. air suspension
23 24 25
4
1
black red
Trailer Control Module TrCM
EBS cable
Junction box
2 core cable:
24V from brake light (red)
Earth (white)
When the brake is released, the yellow brake line is exhausted
via the exhaust on the trailer control valve in the tractor unit.
The EBS vents the service brake cylinder of the braked axles
via its ventilation outlets for the left and right side.
Connection lines between the towing vehicle
and the trailer uncoupled or broken away
If the supply line is uncoupled or breaks away, the trailer brake
control valve initiates emergency braking (automatic braking
with the BBA) by exhausting this line.
If the yellow brake line breaks away, nothing happens unless the
service brake is actuated. When the service brake in the tractor
unit is actuated, the supply line is exhausted via the "defect" in
the brake line, whereupon the TrCM initiates emergency braking
(automatic braking with the service brake system).
For manoeuvred the unhitched trailer, the service brake can
be disengaged by actuating the shunt valve of the TrCM (black
button). The red button must also be pressed in this case to
disengage the parking brake.
The disengagement procedure of the parking brake can only
be carried out, if the pressure in the reservoir is greater than
approx. 3 bar.
21
22
ABS cable connection
1 2
S1B
S1A
DIAG PWR B PWR A