Audi V8 - Page 34

34
Engine - Motronic Subsystems
Combination valve
The combination valve is bolted to the
secondary air duct of the cylinder head.
The vacuum from the secondary air inlet
valve causes the air channel between the
secondary air pump and the secondary duct
of the cylinder head to open.
At the same time, the valve prevents hot
exhaust gases from entering and then
damaging the secondary air pump.
Secondary air inlet valve N112
The secondary air inlet valve is an electro-
pneumatic valve. It is activated by the Motro-
nic control unit and controls the combination
valve.
It releases the vacuum stored in the reservoir
to open the combination valve.
Atmospheric pressure is released to close the
combination valve.
SSP207_016
Valve open
Fresh air from
secondary air
pump
To secondary
air duct
Valve closed
Atmospheric
pressure in control
line from secondary
air inlet valve
Exhaust gas
SSP207_019
SSP207_018
Vacuum in
control line from
secondary air inlet
valve
Filter cap
Atmosphere
To vacuum reservoir
Energised
Not energised
To combination
valves