PRIN. OF INTERNAL COMBUSTION ENGINES - OD1619 LESSON 2/TASK 1
FIGURE 44. EXHAUST MANIFOLD.
d. Muffler (figure 46 on page 56). The muffler reduces the acoustic pressure of
exhaust gases to discharge them to the atmosphere with a minimum of noise. The
muffler is usually located at a point about midway in the vehicle, with the exhaust
pipe between it and the exhaust manifold, and the tailpipe leading from it to the
rear of the vehicle. The inlet and the outlet of the muffler are usually slightly
larger than their connecting pipes so that it may be hooked up by slipping over
them. The muffler is then secured to the exhaust pipe and the tailpipe by clamps.
A typical muffler has several concentric chambers with openings between them. The
gas enters the inner chamber and expands as it works its way through a series of
holes in the other chambers and finally to the atmosphere. Mufflers must be
designed to quiet exhaust noise while creating a minimum of back pressure.
Excessive back pressure could cause loss of engine power, economy, and also cause
overheating. Exhaust system components are usually made of steel. They are
usually coated with aluminum or zinc to retard corrosion.