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Saturday, 26 August 2017

VEHICLE POLLUTION CONTROL DEVICE....... A CATALYTIC CONVERTER

Now a days millions & billions of vehicles are on the road all over the world. Almost every person owned a vehicles. But what about the pollution?? Vehicles exhausts very dangerous pollutants like NO,CO & HC . To feel a healthy air it is necessary to control pollution . In automobile a device named as CATALYTIC CONVERTER  are use reduce reduction . BS3 & BS4 engines are depend on catalytic converter. Lets know what is it , how it works & everything about a CATALYTIC CONVERTER.............
how-Catalytic-Converter-works-TECHIENGINEER-
By Atif Masood (FetchCFD) (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons & By Ahanix1989 at English Wikipedia [Public domain], via Wikimedia Commons

WHAT IS A CATALYTIC CONVERTER??

The vehicle pollution control device used in automobiles, which converts the toxic gases pollutants present in engine exhaust to less toxic pollutants by filtering or absorbing by a catalyst & also a chemical reaction. 

USES & FUNCTION OF CATALYTIC CONVERTER

Catalytic converters are used in exhaust manifold between outlet part of an engine & vehicle silencer for converting the toxic products of vehicle exhaust into non-toxic. It converts nitrogen oxide, carbon monoxide & hydrocarbon like harmful products into carbon dioxide, water vapor & nitrogen gas like less harmful products.


The converter works in either 2-way or 3-way principle. In 2-way converter, only oxidization & reaction happens, but when another sensing unit is added with a 2-way converter it becomes 3-way catalytic converter. The sensing unit actually senses the amount of oxygen in the final exhaust gas & inform to the controller which will then control the air input into the engine. 3-way converter refers to 3regulated emission control system.

How Catalytic Converters Reduce Pollution?

Most modern cars are equipped with three-way catalytic converters.
"Three-way" refers to the three regulated emissions it helps to reduce - carbon monoxide, HCs and NOx molecules. There are two main types of structures used in catalytic converters - honeycomb and ceramic beads. Most automobiles today use a honeycomb structure. The converter uses two different stages of catalysts, a reduction catalyst, and an oxidation catalyst.Both consist of a ceramic structure coated with a metal catalyst, usually platinum, rhodium and,-" or palladium.

What is on the inside of a catalytic converter??

There are two different catalysts in a catalytic converter: One of them tackles nitrogen oxide pollution using a chemical reaction called reduction (removing oxygen). This breaks up nitrogen oxides into nitrogen and oxygen gases (which are harmless because they already exist in the air around us.

TYPES OF CATALYTIC CONVERTER??
  • Two-way Catalyst
  • Three-way Catalyst           

The Reduction Catalyst (First stage)


it uses platinum and rhodium to help reduce the NOx emissions. When

a NO or N02 molecule contacts the catalyst, the catalyst separates the

nitrogen and the oxygen in the form of N2 and O2.



The Oxidization Catalyst (second stage)



Platinum and palladium catalyst oxidizes CO and hydrocarbons with the

remaining oxygen in the exhaust gas.


MEASURES OF REDUCTION OF AIR POLLUTANTS


  •  As the emission standards were tightened, more advanced control strategies were applied that included

             - modifications in engine design and

             - fuel system, control of engine parameters and

               use of sophisticated exhaust after-treatment devices.

  • Reduction of toxic substances emission from combustion engines can be achieved by                                                                                                - primary (inside engine) measure and                                                      - secondary (outside engine) measures.
  • Nowadays secondary measures, in automotive exhaust after-treatment processes a range of advanced technology applied based on oxidation and three-way catalyst filtration process.

Generally, in the BS3 engine, it is used near silencer pipe & in the BS4  engine it is used in a suitable position near the engine.

TO KNOW MORE ABOUT CATALYTIC CONVERTER AND ITS WORKING MECHANISM, SEE 
           WORKING MECHANISM                               ADVANTAGES & DISADVANTAGES

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