Husqvarna 356BFX Series, Workshop Manual

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4 Design and function
4 Design and function
4.1 Resonance pipe
The 356x-series muffler is equipped with a resonance pipe.
A forwards and backwards-moving pulse is created in the
resonance pipe when the motor is running. The resonance
pipe's volume is balanced against the motor's frequency of
revolutions so that the backwards-moving pulse pushes the
unburned exhaust back into the cylinder. This results in lower
emissions and lower fuel consumption.
The drain hose prevents the condensate from ending up at the
bottom of the resonance tube, thus reducing engine output.
4.2 Air to the air filter
The air filter takes air from the fan spiral. Just in front of the
outflow nozzle, by the fan spiral's inner radius, there is an air
intake that conducts the incoming air to the filter. The larger dirt
particles are separated from the incoming air by centrifugal
force. This results in being able to use the blower for long
periods before the air filter needs to be cleaned.