928 GTS V8-5397cc 5.4L DOHC (1994)
Air Injection: Description and Operation
PURPOSE
The air injection system reduces the hydrocarbon (HC) and carbon monoxide (CO) in the exhaust gases by continuing the combustion of unburned
gases after they enter the exhaust system. This is done by injecting fresh air into the catalytic converter to continue the burning process of hydrocarbon
and carbon monoxide.
Fig. 1 Air Flow In Injection System With Low Engine Load
OPERATION
The outside air is drawn through a special air cleaner (located in center front of engine between air intake ducts) into the air pump.
At idle speed and partial load, the air is routed from the air pump through the switching valve (vacuum controlled) to the check valve. From there it
goes through the air tube system, where at the end, it gets injected into the catalytic converter, Fig. 1.