TTS Quattro Roadster L4-2.0L Turbo (CDMA) (2009)
Air Injection: Testing and Inspection
Secondary Air Injection System
The secondary air injection system improves the secondary oxidation within the catalytic converter which are due to the rich mixture during the cold
start phase where the exhaust emissions contain an increased level of unburned hydrocarbons, thereby reducing harmful emissions. The heat released
by secondary oxidation shortens the start-up time of the catalytic converter considerably, as well as significantly improves emissions quality during the
cold-running phase.
‹› During a cold start, the secondary air injection system injects air behind the exhaust valves. This produces an oxygen rich exhaust gas, causes the
after burning and reduces the heating-up phase of the catalytic converter.
‹› In addition, the secondary air injection system is switched on (after a delay) during idle after every subsequent engine start (up to a maximum
coolant temperature) and is checked through on board diagnostic functions.