Pulse Air Injection System: Operation

The pulse air system uses the alternating positive and negative pressure pulsations in the exhaust system to draw in fresh air through the air cleaner. Check valves are used to allow fresh air into the exhaust, but prevent exhaust from flowing back into the intake system.

Air is switched between upstream and downstream injection by 2 vacuum operated control valves. Each control valve is switched by an electrically operated vacuum solenoid.

The vacuum solenoids are switched on and off by the MCU according to engine operating conditions. A vacuum storage tank maintains the vacuum supply to the switching solenoids.