Description & Operation
Air injection system works to reduce exhaust emissions and improve driveability. Control unit engages and disengages air pump through an air injection relay, located in relay box next to brake master cylinder. SeeFig 1 .
Air injection occurs for a maximum of 60 seconds while coolant temperatures above 63°F (17°C), engine below 2500 RPM, full load contact not engaged and/or lambda control operating.
Under these conditions, control unit energizes electro-magnetic clutch of the air pump by air injection relay. Simultaneously, same relay energizes switchover valve which in turn provides vacuum to air injection shutoff valve. Air pump draws air from air filter and delivers to exhaust ports in cylinder head. See Fig 2 .
Air injected from air pump promotes oxidation of CO and HC in the catalyst. Heat created by oxidation brings catalyst to operating condition quicker.