Emission Control Systems

Facts You Should Know About Emission Control Systems

According to the history of the automobile industry, emission control systems were first introduced in the 1960s and it has been in use until this day. However, today’s emissions systems are complicated and more complex compared to those of old. They are not only for ensuring a clean environment but also for the great performance of your vehicle. In our current era, environmental pollution has become a thorn in the flesh causing various havocs and calamities like drought, global warming, and famine.

How the System Works

Typically, emission control system regulates the formation of hydrocarbons, nitrogen oxides, and even carbon monoxides. In addition, it prevents emission and release of gasoline vapors and other dangerous fumes, besides, it usually signals the drivers if the vehicle is emitting more emissions than required. Basically, there are 3 major sources of these pollutants in vehicles:

  • The fuel tank and carburettor – this produces some minor emissions of hydrocarbons that evaporate from fuels and gasoline.
  • The engine exhaust – it emits both the burned and unburned carbon monoxides, oxides of nitrogen, hydrocarbons, and sulphur. Besides, there are traces of various acids and phenols
  • The crankcase – this is also a source of unburned hydrocarbons and some carbon monoxides

In order to control emissions which contribute to a great percentage of engine pollutants there are two types of emission control systems that are used:

  1. The air-injection system – in this system there is an injection of air into the exhaust system where it mixes with the hydrocarbons and monoxides that are unburnt under very high levels of temperatures thus facilitating the combustion process. In this way, the pollutants produced are burned completely. In vehicles which do not use an air pump, they have a catalytic converter which basically converts those partially burnt gases to fully burned ones.
  2. The exhaust recirculation systems (EGR) – in this system a certain percentage of exhaust gases are taken back to the cylinder head, where they mix with fuel and air and latter enters the combustion chamber. The aim of this is to reduce the combustion temperature which reduces production of nitrogen oxides.

The gas cap also prevents any fume from escaping which comes from the fuel tank. In general, the following are used in the functionalities of the emission system: charcoal canister, oxygen sensor, EVAP solenoid, catalytic converter/air-injection, mass air flow sensor, EGR valve, and gas cap.

Benefits of Having Your Emission System Properly Maintained

Symptoms of Malfunctions

Well, you can always notice when your air-injection system is having some malfunctioning, by having growing noise, a warning indicator, and failure in state emission test. When your catalytic converter is having some problem you will experience the reduced power and if it is clogged the vehicle may fail to start. A malfunction in EGR valve may be indicated by hesitation, rough idle and pinging noise when accelerating. When the oxygen sensor has a problem, you will have poor fuel economy, unstable idle, warning indicator light and failing state emissions test. It goes without mentioning signs of malfunctioning crankcase, which is characterised by oil leaks, unstable idle and having oil in air filtering housing.


When your emission system is well maintained, you will have the following benefits:

  • High engine performance
  • Low or reduced emissions
  • Longer engine life
  • You will save some money on fuel
  • You will have no problem with the authorities, you will be compliant to the authority
  • Reduces premature contamination with oil

By installing emission system in your vehicle, you will have played a major role in ensuring you reduce pollution while saving a life somewhere on this planet.