Any internal combustion engine produces exhaust gasses through the combustion process. The byproducts of the combustion are toxic and harmful to the environment and obviously to the passengers too. Therefore, exhaust has to be released with a controlled output to minimize the harmful effects. Another issue with the internal combustion engine is the noise. Mufflers are used to minimize the effect of the noise produced by the engine.
Exhaust
The system of piping and additional components used to guide the gasses after combustion in an internal combustion engine is known as the exhaust system. The main components of an exhaust system are the cylinder head and exhaust manifolds, exhaust piping, catalytic converters, mufflers, resonator and tail pipe.
Exhaust manifold is bolted to the cylinder head. It is usually a single piece or two piece component made of solid cast iron. It collects the exhaust gas from the cylinders at the exhaust stroke and directs it to the exhaust piping leading out of the engine. The temperature of the exhaust manifold reaches very high; therefore, thermal insulation is applied to protect the surrounding components. The piping leads the gas into catalytic converters, which breaks down the toxic byproducts into relatively environmental friendly compounds. For example, unburned hydrocarbons are converted into carbon dioxide gas and water vapour.
Then the piping directs the exhaust gas into the muffler; the function of the muffler is discussed below. From the muffler, gas is directed into the resonator which further reduces the noise. Finally, the tail pipe releases the exhaust gases into the atmosphere.
Muffler
Muffler is a component of the exhaust system to reduce the noise produced by the engine, which is transmitted through the exhaust gas to the outside of the vehicle. Muffler, also known as a silencer has the same functionality of the suppressor used to reduce the noise of a firearm.
The sound pressure from the engine is brought down using the acoustic quieting techniques. Internally, a muffler is a compartment made to pass the gasses through chambers, partitions, louvered tubes, and solid tubes. The designs of the partitions, chambers, and tubes depend on the frequency of the noise produced by the engine. The low frequency noise is reduced by the closed chambers in the muffler which act as cushions, and known as Hemholtz tuners. Chambers with small width/diameter directs the gasses into larger chambers and the process degrade the high pitched noise.
Since the noises produced by different vehicles are different, mufflers are specifically designed to minimize the noise from the engine. The disadvantage of the muffler is that it creates a back pressure zone at the end of the exhaust system. This affects/decreases the engine efficiency.
Exhaust vs Muffler
• Exhaust system is the collection of components that is used to release the exhaust gas into the atmosphere with minimal harmful effects.
• Muffler is an integral component of the exhaust system, and it reduces the noise level of the engine.