It is good news that the exhaust system of an engine works well by spewing out waste gases in order to heave more power for the vehicle. But these emissions are very harmful to the environment. Pollutants like hydrocarbons, carbon monoxide, carbon dioxide, nitrogen oxides, sulfur dioxide, phosphorous, lead, and other hazardous elements that will surely cause air pollution or even green house effect.

Emission parts are products of innovation with an objective of controlling these harmful emissions and irritating exhaust gases from the engines of vehicles. And these harmful pollutants are converted to not so harmful ones so as not to pose further damage to the environment.

Technological advancements in the auto industry have played vital roles in helping reduce the emission of these harmful pollutants. Computer devices have been added to ignition systems for the engine to monitor and adjust itself continuously.

As the engine burns the fuel during combustion process and spews out waste gases, emission parts play a pivotal role to ensure a clean emitted residue. An important emission part is the oxygen sensor. Mounted near the exhaust manifold, the oxygen sensor measures the amount of oxygen contained in the gases leaving the cylinders. It then would send a signal to a microprocessor, which would analyze the reading and operate a fuel mixture or air mixture device to create the proper air/fuel ratio.

This vital information determines how much fuel will be injected into the cylinders. If it becomes faulty, the onboard computer of a vehicle won't be able to accurately measure the exhaust content, and by default, will inject too much fuel rather than too little, because not enough fuel can damage the engine.

Another important emission part is the catalytic converter. An integral component of the exhaust system, the catalytic converter (cat-con). Its main function is to treat the harmful gases before leaving the vehicle. Thus, this reduces a considerable amount of pollution.

The PCV valve siphons blowby vapors from the crankcase into the intake manifold so the vapors don't escape into the atmosphere. One of the beneficial effects of PCV, besides eliminating blowby emissions, is that it pulls moisture out of the crankcase to extend oil life. Moisture can form acids and sludge which can cause major engine damage. So if the PCV valve or hose plugs up, rapid moisture buildup and oil breakdown can result.

The exhaust gas recirculation (EGR) valve is utilized to have some exhaust gases back into the cylinders to lessen the combustion temperature. This valve opens a small passage between the intake and exhaust manifolds. When ported vacuum is applied to the EGR valve diaphragm, it opens the valve allowing intake vacuum to siphon exhaust into the intake manifold. This has the same effect as a vacuum leak, so EGR is only used when the engine is warm and running above idle speed.

A thermostat inside the air cleaner controls vacuum to a valve in the air cleaner inlet. When the engine is cold, the thermostat passes vacuum to the control valve, which closes a flap to outside air allowing heated air to be drawn into the air cleaner. As the engine warms up, the thermostat begins to bleed air, allowing the control door to open to outside air. Thus the thermostat and airflow control door are able to maintain a more consistent incoming air temperature.

With the influx of technology, the auto industry has become more conscious in contributing for cleaner emissions and help lessen the worsening conditions of the environment caused by many forms of pollutions, specifically air. Not only as such, it will further improve engine performance while saving on fuel mileage.