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EMISSION CONTROL SYSTEMS
6 E-3
EFE BUTTERFLY VALVE
AND ACTUATOR
EXHAUST PIPE
4476
Fig. 6E-1 E.F.E.
Systems
SEALED OIL
S E A L E D OIL
\
FILLER CAP
HEAVY ACCELERATION OR
NORMAL
IDLE OR
H I G H ROAD SPEED
ROAD SPEEDS
1287
Fig. 6E-2
PCV System Flow
mixture causing an exhaust backfire. Momentary diverting
of the injection air from the exhaust prevents the backfiring.
The AIR bypass valve allows the pump discharge air to
bypass the injection system at high engine loads. Air bypass
prevents excessively high exhaust system temperatures which
could occur under certain extreme operating conditions. The
valve also bypasses momentarily during deceleration to
prevent backfiring. This function is controlled by the vacuum
differential valve as described above.
The differential vacuum delay and separator valve delays
the air bypassing function during heavy accelerations. This
delay allows air to be injected during acceleration loads, but
bypassed during susbtained high load operation where high
exhaust temperatures can occur. Also incorporated in the
valve is a fuel separator or collector. The collector is designed
to prevent liquid fuel from migrating through the vacuum line
CHECK
I
Fig. 6E-3
PCV Valve Cutaway View
to the vacuum operated components of the AIR system.
PULSE AIR INJECTION REACTION
-
PAIR
Other engines use a system of air distribution pipes and
check valves (called a pulse valve) which relies on the pulses
of the engine's exhaust to siphon air into the exhaust system.
This type of air injection reaction is called Pulse AIR. This
system always injects the air into the exhaust port near the
exhaust valve.
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