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Adventures Under the Hood |  |
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Adventures Under the Hood | |
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The Pulse Air System consists of two identical
assemblies. Each has some tubing, a computer-controlled
vacuum solenoid , a
vacuum-operated air valve (pictured right), and a
reed-type checkvalve (pictured below). Injecting air
(oxygen) into the exhaust stream at the exhaust pipe or
catalytic converter aids in the further oxidation of
partially burned hydrocarbons. This system is used
instead of the air pump found on many engines, and has
the advantage of requiring a lot less plumbing.
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There are two assemblies, one on each side of the
engine. The one on the driver's side injects filtered air
into the the catalytic converter
(downstream), and the one on the passenger side injects
air into the exhaust pipe just below the exhaust manifold
(upstream).
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| Checkvalves |
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Here is one side of the Pulse Air System. It relies
on pressure pulsations in the exhaust stream and a
one-way checkvalve to draw air down from the air cleaner.
When it feels like it, the computer actuates the vacuum
solenoid which actuates the air valve, allowing air to
flow from the filtered side of the air cleaner down
through the reed-type checkvalve to the catalytic
converter or exhaust pipe. The checkvalve should not
allow exhaust to flow up the tube into the
air cleaner, or bad things happen.
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With the engine warm and idling, and with the lid off the air
cleaner, it is easy to hear the Pulse Air tubes resonating when
they are energized. Holding your hand over them you can feel the
pulsing. However, the overall pressure is negative.
If you are looking in the air cleaner, and the Pulse-Air tubes do not appear to be doing anything ever, it's possible that one or both tubes have rusted through somewhere. These tubes are supposed to resonate, like trombone or trumpet tubing. If there is a hole somewhere this will not happen.
Note that a properly operating PulseAir system will not affect engine power output, the point being that removing it will not make the engine run any better, but will cause an increase in emissions.