BPW ECO Tronic EBS Operating And Installation Instructions page 66

5 Installation and Operating Instructions
5.2 Air suspension
5.2.1 Standard air suspension valve
When the vehicle is being loaded, the body (frame) approaches
the axle, causing the leverage and the control lever to rise and
allowing access via the carrier shaft, cam and pistons. Reserve
air from connection 1 now fl ows past the check valve, over the
opened infl ow, through the space between pistons and inlet
bodies via connection 21 and 22 to the air bags. This means
the body (frame) is raised until the point where the control lever
is horizontal once again, that is to say in the fi nishing position.
When the vehicle is being unloaded, the body is raised upwards
due to the higher airbag pressure. The control lever is moved
downwards through the leverage. The movement of the control
lever is transferred via the carrier shaft as well as the cam to the
piston, which opens the outlet during its downwards movement.
Compressed air now fl ows through the open outlet from the air
bags into the atmosphere, which causes the body (frame) to
lower once again into the driving position, (air suspension valve
control lever horizontal).
Vehicles are usually only equipped with one air suspension
valve. Exceptions can be found, for example in the case of fi fth
wheel trailers or semi trailers with independent suspension. The
airbags on the right as well as the left side of the vehicle are
supplied via this one air suspension valve with cross-throttling.
Supplementary functions
• Air suspension valve with cross-throttling
• Air suspension valve with cross-throttling and height
limitation
• Air suspension valve with zero point adjustment for 2nd
driving height
Air suspension valves with cross-throttling
Air suspension valves with cross-throttling prevent the vehicle
becoming unstable when cornering, as would occur if the
pressure of the air bag on the outside of the curve were to
even out to match that of the air bag on the inside of the curve
(danger of an accident; tendency already apparent in the body
while taking the corner would thus be reinforced even further). A
special formation of the inlet valve allows for increased pressure
compensation to be achieved between connection 21 and 22
and therewith between the right and left air suspension valve
(vehicle side).
Assembly instructions - Mechanical
The levelling valve has to be installed vertically with exhaust
port at bottom. For fi xing use at least two M8 screws. The valve
should be secured via the middle of the axle. Tightening torque:
15 Nm (13.5 – 16.5 Nm).
The freedom of movements of the eccentric shaft must be
tested. The leverage must be installed free of tension. The
marking on the eccentric shaft must point in the direction of
the steering device in order to ensure the operation of the air
suspension valve on the correct side (see Fig. 118).
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Technical Data
Operating pressure, dyn.:
Permitted dyn. bellow pressure:
Operating temperature:
Operating range (charging - and exhausting): 45°
Side of control: on the left and on the right
Dead angle at 7 - 8 bar: 2°
Connection designation:
1
21/22
3
Turning the operating handle 180° achieves the same
function within a tolerance range of 3.5°, as in the
adjustment shown.
Piping diagram
22
21
Fig. 117
Adjustment of mechanical part
Arrow marking must indicate direction of linkage
Fig. 118
pe max. 13 bar
pe max. 20 bar
- 45°C to + 85°C
= Energy fl ow
= 1./2. Energy release
= Venting
1
3