|
The exhaust system removes the spent
exhaust gases from the engine. The exhaust system must do this while
keeping noise levels to a minimum and preventing the entrance of poisonous gases
into the passenger compartment. In most cases, service is limited to
replacing parts and ensuring that the system is not leaking.
|
|
Systems can vary among vehicles but the basic components consist of:
|
 |
Exhaust Manifold: The
exhaust system begins at the exhaust manifold, a set of steel pipes that
are attached to the engine. Combustion gases that have escaped through the
exhaust valves collect in the manifold after burning. These gases are
pushed along by the pressure of the incoming gases until they flow into
one or more steel exhaust pipes.
|
Catalytic Converter: The gases go to the catalytic
converter, a device that looks like a large muffler and contains precious metals
(catalysts) that cause a chemical reaction inside. These metals turn
carbon monoxide and hydrocarbons into harmless substances such as water and
carbon dioxide.
 Note:
This component of the exhaust system
is a Federally-mandated emission control component, and the manufacturer
must warranty it for five years or 50,000 miles (extended to eight
years/80,000 miles for new cars).
|
Muffler: From the converter, gases
go on to the muffler, an oblong metal noise catcher that absorbs much of
the sound that combustion creates by routing sound waves through its
perforated pipes. Mufflers are designed to reduce, or muffle, the
sound of the exhaust system. They should silence the exhaust effectively
while providing freedom from objectionable back pressure. Back pressure
occurs when the exhaust gases can't pass through the muffler fast enough
and thus build up pressure that reduces the ability of the engine piston
to push the gases out of the cylinder.
|
Resonators - In
addition to a muffler, some systems have a resonator to further dampen the
exhaust pulsations. The resonator is a small version of the muffler.
|
