Repair manual

SULEV 2.0L TFSI Engine
28
Secondary Air Injection Solenoid Valve
N112
Unlike earlier valves, the newly developed Secondary Air
Injection Solenoid Valve N112 operates electrically. It is
mounted directly to the cylinder head by bolts. When
compared to the pneumatic valves used previously, the
secondary air intake valve is extremely rugged.
The valve also has a non-return function which prevents
exhaust gases from flowing back into the secondary air
system, even when the valve is open (illustration at right).
Valve Activated
When N112 is activated by the ECM, secondary air flows
through the valve to the cylinder head.
A solenoid lifts the closing element off the valve plate.
Secondary air flows through the orifices in the valve
plate.
Non-Return Function
When secondary air flows through the valve, the non-
return element is pressed down and against a spring,
holding the valve open.
If exhaust gases flow back into the secondary air intake
valve, secondary air pressure will decrease.
As a result, the non-return element lifts off the closing
element with spring assistance and seals the orifices in
the valve plate.
In this way, secondary Air Injection Valve and Secondary
Air Injection Pump Motor V101 are protected against
possible damage by hot exhaust gases.
Branch
Connecting to
Cylinder Head
Electrical
Connection
Closing
Element
Valve
Plate
Coil
Armature
To
Cylinder
Head
From Air
Filter
Non-Return
Element
Closing
Element
Spring
Valve
Plate
Exhaust
Gas