Pulsed Secondary Air Injection - Honda S2000 Service Manual

Fuel and Emissions Systems
System Descriptions (cont'dl
Pulsed Secondary Air Injection
The Pulsed Secondary Air Injection advances the activation of the catalytic converter and reduces the hydrocarbons
(HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas.
The system operates after the engine starts under the followig conditions:
. The engine coolant temperature is between 32'F and 158"F {0"C and 70"C)
. The difference is more than 36'F (20'C) between the engine coolant temperature when the engine is started and
when the engine was stopped in the previous driving cycle.
AIR CONTROL VACUUM
CHECK VALVE
N o . 6 A C G -
(15A) FUSE
AIR PUMP >-
{604I FUSE
!,,1
::l
AIR PUMP
RELAY
When the engine is cold and first started, the air pump pumps fresh air into the exhaust porls. The amount of air
entering the exhaust is regulated by an air control valve which is controlled by the ECM. The system does not work for
more than 60 seconds at a time. Actual operating time will very depending on the difference between engine coolant
temDerature and intake air temDerature.
When fresh air reacts with any unburned exhaust gases, the exhaust gas temperatures rise. This rise in temperature
promotes faster warm-up of the catalytic converter. resulting in cleaner emissions du ring cold stan-up.
When the air induction system is not operating, the air control solenoid closes the air control valve to prevent any
exhaust gases from flowing back into the sytem.
AIR CONTROL VALVE VACUUM
CONTROL SOLENOID VALVE
AIR PUMP
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