catalytic convertor pant

8/2/2019 Catalytic Convertor Pant

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http://en.wikipedia.org/wiki/File:DodgeCatCon.jpg


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There are millions of vehicles on the road inthe India, and each one is a source of air

pollution.To solve those problems, cities, states and theCentral Government create clean-air laws thatrestrict the amount of pollution that Vehicles

can produce.In 1975 a new device was invented i.e.catalytic converter.

The job of the catalytic converter is to convertharmful pollutants into less harmful emissionsbefore they ever leave the vehicles exhaust

system.


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Pollutants Produced by a vehicle Engine

In order to reduce emissions, modern engines control

the amount of fuel they burn.They try to keep the air-to-fuel ratio very close to thestoichiometric point, which is the ideal ratio of air tofuel.

Theoretically, at this ratio, all of the fuel will be burnedusing all of the oxygen in the air.For patrol, ratio is 14.7:1,The fuel mixture actually varies from the ideal ratio

quite a bit during driving.Sometimes the mixture can be lean (an air-to-fuelratio higher than 14.7), and other times the mixturecan be rich (an air-to-fuel ratio lower than 14.7).


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The main emissions of a vehicle engine are:Nitrogen gas (N2) - Air is 78-percent nitrogen gas,

and most of this passes right through the vehicleengine.Carbon dioxide (CO2) - This is one product ofcombustion. The carbon in the fuel bonds with the

oxygen in the air.Water vapor (H2O) - This is another product ofcombustion. The hydrogen in the fuel bonds with theoxygen in the air.

These emissions are mostly benign, although carbondioxide emissions are believed to contribute to globalwarming. Because the combustion process is neverperfect,


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some smaller amounts of more harmfulemissions are also produced in vehicle engines.Catalytic converters are designed to reduce all

three:Carbon monoxide (CO) is a poisonous gasthat is colorless and odorless.

Hydrocarbons or volatile organiccompounds (VOCs) are a major component ofsmog produced mostly from evaporated,

unburned .fuel.Nitrogen oxides (NO and NO2, together calledNOx) are a contributor to smog and acid rain,which also causes irritation to human mucus

membranes.


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CATALYTIC CONVERTOR A catalytic converter helps in preventing emission of

noxious gasses into the atmosphere. It is tuber in shape and compresses a honeycomb

metallic or ceramic disc, coated with noble metals likeplatinum palladium and Rhodium.

Noble metals play the role of catalysts in reactionwhich renders exhaust components like carbonmonoxide and hydro-carbons harmless by convertingthem into carbon dioxide and water respectively.These metals are spread over a large surface to

provide intimate between exhaust gases andcatalysts.

Catalytic converters are required to simultaneouslyremove targeted pollutants, resist catalyst poisoningand last long. There are two types of catalytic

apparatuses in Automobiles:-


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1) Two Way System.

Using platinum andpalladium which removes only

carbon dioxide and hydrocarbons leaving Nitrogenunchanged.


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A two-way (or "oxidation") catalytic converter has

two simultaneous tasks:Oxidation of carbon monoxide to carbon dioxide:2CO + O2 2CO2

Oxidation of hydrocarbons (un-burnt and partiallyburnt fuel) to carbon dioxide and water:CxH2x+2 + [(3x+1)/2]O2 xCO2 + (x+1)H2O(a combustion reaction)This type of catalytic converter is widely used ondiesel engines to reduce hydrocarbon and carbonmonoxide emissions.


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CATALYTIC CONVERTER


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) Three way catalytic systemEmploy platinum, palladium to remove all three

pollutants simultaneously.The specific reactions vary with the type ofcatalyst installed. Most present-day vehiclesthat run on gasoline are fitted with a "three

way" converter, so named because it convertsthe three main pollutants in automobileexhaust:an oxidizing reaction converts carbon monoxide

(CO) and unburned hydrocarbons (HC), and areduction reaction converts oxides of nitrogen(NOx) to produce carbon dioxide (CO2),nitrogen (N2), and water (H2O).


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Since 1981, "three-way" (oxidation-reduction)catalytic converters have been used in vehicleemission control systems The reduction andoxidation catalysts are typically contained in acommon housing, however in some instances theymay be housed separately. A three-way catalytic

converter has three simultaneous tasks:Reduction of nitrogen oxides to nitrogen and oxygen:2NOx xO2 + N2

Oxidation of carbon monoxide to carbon dioxide:

2CO + O2 2CO2Oxidation of unburnt hydrocarbons (HC) to carbondioxide and water:CxH2x+2 + [(3x+1)/2]O2 xCO2 + (x+1)H2O.


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One of its biggest shortcomings is that itonly works at a fairly high temperature.

When a vehicle is started from cold, thecatalytic converter does almost nothing toreduce the pollution in exhaust.

One simple solution to this problem is tomove the catalytic converter closer to theengine.This means that hotter exhaust gases reachthe converter and it heats up faster, but thismay also reduce the life of the converter byexposing it to extremely high temperatures.


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Preheating the catalytic converter is a good wayto reduce emissions.

The easiest way to preheat the converter is to useelectric resistance heaters.Unfortunately, the 12-volt electrical systems onmost light vehicles don't provide enough energy or

power to heat the catalytic converter fast enough.Most people would not wait several minutes for thecatalytic converter to heat up before starting their

car.Hybrid cars that have big, high-voltage batterypacks can provide enough power to heat up thecatalytic converter very quickly.


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Catalytic converters in diesel engines do not workas well in reducing NOx.Diesel engines run cooler than SI engines, and the

converters work better as they heat up.Some experts have come up with a new system thathelps to combat this.They inject a urea solution in the exhaust pipe,before it gets to the converter, to evaporate and mixwith the exhaust and create a chemical reaction thatwill reduce NOx. Urea, also known as carbamide, is

an organic compound made of carbon, nitrogen,oxygen and hydrogen.Urea reacts with NOx to produce nitrogen and watervapor, disposing more than 90 percent of the

nitrogen oxides in exhaust gases


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Catalytic converter fitted vehicles

can use only unladed petrol. Leadedpetrol is harmful for converterbecause lead poisons the noblemetals in the device and reduces itspotency.

It has few drawbacks, also

It is costly affair.

Useless for short journeys.

May fail without being noticed by driver.


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UNLEADED PETROL

The regular petrol sold presently atmajority of the pumps in the country

has lead in the form of TETRA ETHYLLEAD (TEL). Lead is anenvironmentally toxic chemicaltherefore it is being phased out ofpetrol and the petrol is reformulatedto lead free petrol which is known asunleaded petrol.


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Since 1923 lead is blended in petrolas an additive at the end stage of its

production in the refineries in the formof Tetra Ethyl Lead. The purpose ofadding TEL to petrol is to improve its

combustion quality there by improvingits octane number and in turn antiknocking values.

Although, TET performs will as an antiknock

ingredient, it pollutes the air with,poisonous lead compounds. Lead effectslearning & intellectual ability of children. It

also prevents use of catalytic converters.


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To do away with this public healthhazarded, concept of Lead free

petrol comes which contains arelater proportion of anti-knockhydrocarbons. Todays design

allows for use of petrol withoutlead compounds. These unleadedpetrol arte made withhydrocarbons that have high anti-

knock properties. Some refinersalso add special oxygen containingchemicals to these fuels toincrease their octane numbers.


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UNLEADED PETROL & CATALYTICCONVERTER FACTS THAT ONE MOST KNOW

1) Catalytic converter fitted vehicle areraner vehicles an noxious emissionsfrom such vehicles are low.

2) From 1.4.1995 all new four wheelervehicles which run on unleaded petroland are fitted with catalytic converter

alone would be registered in the fourmetro cities.


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3) New four wheeler petrol vehiclessold any where in the country fromApril 1st 1995 would be eligible forregistration in a foresaid metrocities only if they are fitted with

catalytic converters.


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CATALYST A CATALYST IS A SUBSTANCE THAT HELPS TO

MAKE A CHEMICAL REACTION IN BECOMING A PART OFIT BUT ULTIMATELY IT REMAIN UNCHANGED.

THE CATALYST ELEMENTS USED IN THE C C AREPLATINUM,PALLADIUM, AND RHODIUM.THESEELEMENTS ARE USED ALONE OR IN COMBINTION TO

CHANGE THE UNDESIRABLE CO, HC AND NOX INTOHARMLESS VAPOUR,,NITROGEN, OXYGEN AND LESSHARMFULL CO2.

THESE RARE METAL ELEMENTS THINLY COATED BY ASUBSTRATE SUPPORTED INSIDE THE CONVERTER

SHELL. THE NEUTRAL SUBSTRATE IS CERAMICMATERIAL DESIGNED TO WITHSTAND THE HIGHTEMPERATURE OF THE EXHAUST GASES AND THEADDITIONAL HEAT IS CAUSED BY THE CHEMICALCHANGES OF CATALYTIC REACTION.


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The NOx CO AND HC MOLECULES ENTER THECC AND CONTACT AND ATTACH THEMSELVESTO THE RARE METAL THAT COVERS THESUBSTRATE.WHEN HEAT IS APPLIED CATALYTICPROCESS STARTED AND THE MOLECULES TOREARRANGE THEMSELVES INTO THE LESSHARMFUL ELEMENTS.

OXIDATION PROCESS-THE PROCESS THROUGH

WHICH HC AND CO ARE CONVERTEDTORELATIVELY HARMLESS BY-PRODUCTS ISCALLED OXIDATION.

HC AND HEAT+ OXYGEN _____MILD REACTION

HC AND CO+HEAT+OXYGEN (PT/PD) __-------

STRONG REACTION H2O+CO2.

PLATINUM OR PALLADIUM ADDS OXYGEN

HC+CO+HEAT+OXYGEN-------H2O+CO2


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REDUCTION PROCESS:THE PROCESSTHROUGH WHICH THE NOX IS REDUCED ISCALLED REDUCTION

RHODIUM REMOVES OXYGEN

NOX+HEAT--------NOX{LOWER LEVEL}------NITROGEN + OXYGEN

REDUCTION IS THE REMOVAL Of OXYGENFROM THE EXHAUST GASES.

THE ACTION TAKES PLACE IN THE THECONVERTER WHEN THE GASES PASSES

THROUGH THE CATALYSTS (RHODIUM)REDUCED THE NOX TO HARMLESSNITROGEN AND OXYGEN


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CATALYTIC CONVERTER

CONVERTER HAS A REDUCING CHAMBER FOR BREAKING


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CONVERTER HAS A REDUCING CHAMBER FOR BREAKINGDOWN NOX AND AN OXIDISING CHAMBER FOR OXYDISING HCAND CO

THE EXHAUST PASSES THROUGH THE REDUCING CHAMBER

FIRST .ADDITIONAL OXYGEN IS INTRODUCED INTO THEOXYDISING CHAMBER TO MAKE IT MORE EFFICENT.A TWO-WAY CONVERTER OXIDISES HC AND CO;A THREE WAYCONVERTER OXIDISES HCAND CO AND REDUCES NOX.


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DEFECTS IN CATALYTIC CONVERTER

CLOGGING.

POISONING

BAD EXHAUST VALVE ON THEENGINE.

FOULED PLUGS CAUSING UNBURNEDFUEL TO OVERHEAT THECONVERTER.

CATALYTIC CONVERTER CHECK


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CATALYTIC CONVERTER CHECK

1 INSERT AN EXAUST GAS SAMPLE PROBE INTOTHE TAIL PIPE AT LEAST 6 INCHES.THE ENGINEMUST BE AT NORMAL OPERATING TEMPT ATCURB IDLE.

2 THE CO-READING ON ANALYSER MTR SHOULDBE WITH IN A RANGE BETWEE0.I TO .3

3 IF THE READING IS OVER REPAIR OR

ADJUSTMENT MIGHT BE NEEDED TO CORRECTEXCESSIVE EMMISSION BECAUSE THE CC ISNOT OXIDISING FUEL FROM ENGINE.THE CCMIGHT BE FAULTY.


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REPLACING A CATALYTIC CONVERTER

THERE ARE TWO TYPES OF REPLACEMENT:

INSTALLATION KITS-SUCH KITS INCLUDEALL NECESSARY COMPONENT FOR THE

INSTALLATION DIRECT FIT CATALYTIC CONVERTER


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PRECAUTION WITH NEW


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PRECAUTION WITH NEWTECHNOLOGY

THE CATALYTIC CONVERTER HAS BEEN FITTED TOPRTROL VEHICLES FOR A NUMBER OFYEARSAND IS A LEGAL REQUIREMRNT.ALTHOUGH

FAIRLY BASIC IN CONSTRUCTION, ANDMAINTENANCE FREE, BUT THERE ARE SOMEPREACAUTIONS THAT ONE CAN UNDERTAKE TOEXTEND THE LIFE OF THE UNIT FITTED TOVEHICLE.

NEVER USE LEAD REPLACEMENT FUEL IN CARWITH A CATALYTIC CONVERTER..

If the vehicle has a misfire do not drive


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If the vehicle has a misfire, do not driveit until it has been rectified. If the ignitionsystem is at fault then unburnt fuel will

be going into the catalyst.

Never push-start or tow-start the vehicle- this will again put unburnt fuel into the

catalyst and damage it. A reaction calledthermal aging takes place which, putsimply, overheats the catalyst.

If the engine puts out excessive bluesmoke, then the vehicle should not bedriven as damage could result.

Frequent cold starts one after another should


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Frequent cold starts one after another shouldbe avoided.

Actuation of the starter for a long time duringstarting should be avoided, as fuel is beinginjected into the engine. Fuel can coat themetals in the catalytic converter giving rise toproblems.

Do not allow the fuel tank to become empty(irregular fuel supply leads to engineoverheating).

Never use fuel or engine oil additives.

The catalytic converter operates at hightemperatures - do not park over dry grass afterthe vehicle has been on a run.

The catalytic converter should last around 50,000 -

100,000 miles on a well-maintained and driven vehicle


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DRAWBACKS

IT IS A COSTLY AFFAIR.

USELESS FOR SHORT JOURNEYS ASIT STARTS WORKING AT250 DEGREECENT.

MAY FAIL WITHOUT BEING NOTICEDBY DRIVER.

UNLEADED PETROL AND CATALYTIC


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UNLEADED PETROL AND CATALYTIC

CONVERTER CC FITTED VEHICLE ARE CLEANER VEHICLE AS

NOX EMISSION FROM SUCH VEHICLE ARE LOW.

FROM 1.41995. ALL NEW FOUR WHEELERWHICH RUN ON UNLEADED PETROL FITTEDWITH CC ALONE WOULD BE REGISTERED IN

THE FOUR METROCITIES

IF YOUR VEHICLE IS FOUND VIOLATING THEEMISSION STANDARD YOU WILL BE FINED RS1000/-FOR THE FIRST OFFENCE ANDRS2000/-

FOR THE SECOND AND SUBSEQUENTOFFENCES.


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catalytic convertor pant

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