Secondary Air Injection (Air) Control Block Diagram; Secondary Air Injection (Air) Control Operation; Outline; Operation - Mazda RX-8 2004 Service Highlights

SECONDARY AIR INJECTION (AIR) CONTROL BLOCK DIAGRAM

• The PCM determines the engine conditions based on input signals and sends an operation signal to the AIR
solenoid valve and the AIR pump relay.
ECT SENSOR
IAT SENSOR
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SECONDARY AIR INJECTION (AIR) CONTROL OPERATION

Outline

• The AIR relay supplies power to the AIR pump and drives the pump.
• The AIR solenoid valve opens and closes the valve switching to feed intake manifold vacuum and barometric
pressure which is fed to the actuator in the AIR control valve.
• At cold-engine start, the AIR solenoid valve switches for vacuum feed, and opens the AIR control valve. The
AIR pump relay also turns on, driving the AIR pump and sending air to the exhaust port through the AIR control
valve. As a result, the unburnt gas in the air and exhaust gas are mixed and it recombusts to activate the
catalytic converter rapidly.

Operation

• At cold-engine start and when the catalytic converter temperature is low, the AIR pump relay turns on to drive
the AIR pump. When the AIR pump relay turns on, an on signal is also sent to the AIR solenoid valve
simultaneously.
• The ignition timing, the fuel injection amount and the throttle valve opening angle are controlled intentionally so
that the air mixes with the exhaust gas easily, and the secondary air amount corresponding to the unburnt gas
amount is discharged for rapid and complete reburn.
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EVAPORATIVE PURGE CONTROL OUTLINE

• The purge solenoid valve operates according to the engine operation conditions, controlling the optimum air/
fuel ratio while feeding evaporative gas to the intake air passage and inhibiting its atmospheric release.
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EVAPORATIVE PURGE CONTROL BLOCK DIAGRAM

• The PCM determines the engine conditions based on input signals and sends an operation signal (duty signal)
to the purge solenoid valve.
ECT SENSOR
IAT SENSOR
BARO SENSOR
ECCENTRIC SHAFT
POSITION SENSOR
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01–40–30
CONTROL SYSTEM
PCM
PCM
CHU014000140S31
AIR SOLENOID VALVE
AIR PUMP RELAY
CHU0140S025
CHU014000140S32
CHU014000140S33
CHU014000140S34
PURGE SOLENOID VALVE
CHU0140S026