Emission Control

 The system that carries exhaust gases from the combustion chamber to the rear of the car is  called the exhaust system.

The exhaust system has one or two exhaust manifolds, and an exhaust  pipe, intermediate  pipe, and tail pipe. The exhaust manifold collects  exhaust from the engine's cylinders.The exhaust pipe, intermediate pipe  and tail pipe carry exhaust to the back end of the car.The  mufler quiets  engine noise. 

The burned gases removed from the combustion chamber contain such harmful emissions as  hydrocarbons (unburned)  ,carbon monoxide , nitrogen oxides

There are five popular systems used to reduce emissions: the crankcase ventilation system, the evaporative emission control system, the Exhaust Gas Recirculation (EGR) system, the air injection system and the catalytic converter system.

In addition to these emission systems, modern vehicles incorporate an electronically controlled fuel injection system, which further reduces emissions. Note: Not all vehicles are equipped with these emission systems.

The purpose of the positive crankcase ventilation (PCV) system is to take the vapors produced in the crankcase and piston blow-by, and redirect them into the air/fuel intake system to be burned during combustion.

Exhaust gas recirculation (EGR) systems reduce the amount of oxides of nitrogen produced during the combustion process.

The function of the fuel evaporative control system is to trap and store evaporative emissions from the gas tank and carburetor. A charcoal canister is used to trap the fuel vapors. The fuel vapors adhere to the charcoal, until the engine is started, and engine vacuum can be used to draw the vapors into the engine, so that they can be burned along with the fuel/air mixture.

The catalytic converter looks like a muffler. It is located in the exhaust system ahead of the muffler. As hydrocarbons or carbon monoxide in the exhaust are passed over the catalyst, it is chemically oxidized or converted to carbon dioxide and water.