Emission Control System - Overview, How to Control & Effect

Installing Emission Control Systems is necessary to make these vehicular emissions safe for environment. These devices destroy harmful chemicals from the smoke before letting it out.

The functioning of Emission Control Systems is pretty simple. This blog will take you through everything about vehicle emission control.

An Emissions Control System in vehicles include devices that reduce hazardous gas during combustion process. Car owners need to install emission control devices to minimise exhaust emissions from the above sources. 

Emissions from exhaust or tailpipe include burnt and unburnt gases that constitute nitrogen oxide(NO) and Carbon monoxide(CO) while the fuel tank releases hydrocarbons. A combination of these gases is toxic to our environment and should be taken care of.

Though most vehicles today come with technologies to limit the release of toxins. Implementing certain emission control methods will ensure the release falls under the norms set by authorities.

To control vehicular emission, car owners can install the following components into emission control systems:

1. Catalytic Converter

This is one of the main components of an emission control system in vehicles. This Catalytic converter is inserted into the exhaust system to get rid of the pollutants. Exhaust gases passes through packed metallic beads made of platinum, rhodium, and palladium. 

Platinum acts as a catalyst for oxidising the emissions. By conducting the heat, the converter converts CO and hydrocarbons into carbon dioxide and water vapour. It requires heat during the cleansing process. Lack of heat or warmth can disrupt the neutralising procedure.

Catalytic converters are of two types, one-way converters, and two-way converters.

2. Evaporative Control System

Years ago, harmful gases from fuel tanks or carburettors were directly emitted into atmosphere. However, nowadays usage of evaporative control systems are necessary to control air pollution through fuel tanks.

Charcoal canisters control the release of hydrogen into atmosphere from fuel tanks. This canister has two input lines and one output line. One input line receives vapours from the fuel tank while the other absorbs vapours from the engine section. Carbon present in charcoal traps hydrocarbon emissions before vapours are released into air.

The Evaporation control system is also beneficial for fuel savings. Fuel vapours trapped in the canister are sent back to the combustion chamber through the output line. Fuel emissions, are finally released when fuel tank is opened for refuelling.

Hence, implementing charcoal canisters is both economical and saves the environment. It also helps improve efficiency of your vehicle.

3. Exhaust Gas Recirculation (EGR)

The Exhaust Gas Recirculation (EGR) system cools down an automobile's engine while lowering exhaust emissions. As the name suggests, EGR recirculates some part of released exhaust gas back to combustion chamber of an engine.

The engine produces nitrogen oxide(NO), a toxic air pollutant. EGR system dilutes its impact and sends it back to the engine. However, any automobile engine is not designed to function with residue gases. Therefore, gas entering combustion chamber of engine has to be monitored. Advanced technology in vehicles helps solve this issue.

Exhaust gas is already burnt gas, which helps decrease vehicle combustion capacity. Less combustion means low generation of heat. This ultimately lowers emissions from vehicles.

An Exhaust Gas Recirculation system allows diesel vehicles to lower NO emissions. On the other hand, for petrol-based automobiles, EGR increases vehicular efficiency.

4. PCV Valve

A Positive Crankcase Valve (PCV) allows the crankcase to dilute and divert gas back to combustion chamber. PCV is a unidirectional emission device. One end of the PCV is connected to the crankcase, for vapours to enter. An extra opening called a breather line allows PCV access to fresh air.

Usually, vapours produced during combustion pass through cylindrical chambers to pistons. Following this, they enter crankcase. Older vehicles release toxic vapours directly into atmosphere.

However, PCV emission control system redirects any unburnt gas to air/fuel intake chamber to burn it again. Finally, the exhaust chamber finally releases the fully burnt gas, leading to less emission from a crankcase.

If a vehicle’s PCV gets clogged, vapours travel to automobile air filter housings. In the worst-case scenario, excessive air pressure will break seals and cause oil leaks.

5. Air Injections

Despite several emission control methods, residual vapours might contain some toxic elements. To ensure that the emissions are mostly toxin-free,  air injections are important.

Fuel, oxygen and heat present in combustion chamber produce combustion. This gives out toxic gases like carbon monoxide and unburnt hydrocarbons. They tend to pass out of the tailpipe polluting the environment. Air Injections burn down these unburnt hydrocarbons and CO before releasing them into the atmosphere.

Located near engine exhaust, Air injection system constitutes of a pump to burn down excess pollutants with fresh air. The pump draws fresh air from your vehicle’s manifold intake. Air Injection systems do not harm the engine or combustible chamber.

Today, the growing amount of automobiles and their uncontrolled emissions are depreciating the quality of our lives. 

We know how these toxic pollutants lead to depleting ozone layer, lung diseases, and global warming issues. Following are the effects of automobile emissions on environment and health:

• Inhaling the toxic gases with high CO triggers breathing problems like Asthma and susceptible lung diseases like bronchitis, pneumonia.
• Unchecked automobile emissions increase the Air Quality Index (AQI) level than normal- this leads to accumulation of smogs across cities.
• Smog interrupts regular traffic movements, not just roads but air traffic as well.
• The depletion of ozone layer due to rising CO emissions increases entry of UV rays along with sunlight. This triggers skin cancer in humans.
• Depleting ozone layer contributes to increasing global warming.

Governments around the world are mandating strict emission norms to ensure that future generations inherit a cleaner atmosphere. Along with monitoring residual gases, emission control devices give your vehicle better efficiency and longevity. Thus, vehicle owners must keep track of and replace their emission control system from time to time to avoid breaking the law.