Reed Valve Air Injection: Operation: GLC
The large reed valve is connected directly to exhaust manifold to increase amount of secondary air injected into exhaust gas stream. The small reed valve is connected to an air gallery which delivers injected air to each exhaust port. When exhaust pulsations are less than atmospheric pressure, reed valves are pushed open by incoming fresh air provided by the air control valve. When exhaust pressure exceeds atmospheric pressure, reed valves are pushed closed to prevent injection of fresh air. Reed valves act as one-way valves.
The air control valve is located between air cleaner and air silencer. This valve controls the amount of fresh air delivered to the reed valves according to intake manifold vacuum signals received from the water thermo valve. An air by-pass orifice is provided to prevent collapsing of connection pipes when air control valve is closed.
The water thermo valve is located in the bottom radiator tank. This valve controls the intake manifold vacuum signal sent to the air control valve. Below 64° F (18° C), valve is open to transmit vacuum to air control valve. Above this pre-determined temperature, valve is closed and no vacuum is present.