CATALYTIC CONVERTER Introduction M illions of cars on the road are a source of air pollution T he amount of pollution that all the cars produce together can create big problems G overnment ID: 586637
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Slide1
MOHAWK®
CATALYTIC
CONVERTERSlide2
IntroductionM
illions
of cars on the road are a source of air pollution.
T
he
amount of pollution that all the cars produce together can create big problems.
G
overnment
create clean-air laws that restrict the amount of pollution that cars can produce to solve it.
A
utomakers
have made many improvement to car engines and fuel systems to keep up with these laws.
I
n
1975 an interesting device called a
catalytic converter
was created.
C
atalytic
converter is to convert harmful pollutants into less harmful emissions before they ever leave the car's exhaust system.Slide3
The exhaust from the combustion in a cars engine is comprised of six main ingredients. Nitrogen gas, carbon dioxide, and water vapor are three of the main emissions. These gases
do not cause damage
to the atmosphere.
Carbon Monoxide, other hydrocarbons, and Nitrogen Oxides
result in a majority of
the pollution caused by cars
.
Carbon Monoxide is a colorless and odorless gas that can kill you if too much is inhaled.
Hydrocarbons come out of an engine's exhaust from unburned fuel. These hydrocarbons can be broken down by the sun, creating ground level ozone, also known as smog.
Nitrogen oxides can cause acid rain.
Catalytic converters are designed to reduce these last three emissions.Slide4
What is Catalytic ConverterA device installed on vehicle that used to reduce the toxicity of emissions from an internal combustion engine.
M
ost
commonly used in motor vehicle exhaust systems and other engine-equipped machines.
P
rovides
an environment for a chemical reaction wherein toxic combustion by-products are converted to less-toxic substances.
a)Location of catalytic converterSlide5
ConstructionThe catalytic converter consists of several components:
The core is often a ceramic/stainless steel foil honeycomb.
- increases the amount of surface area
-support the catalyst. Also called a "catalyst support“.
b) Ceramic honeycomb
c) Stainless steel honeycombSlide6
A wash coat is used to make converters more efficient because a mixture of silica and alumina. -will forms a rough and irregular surface. -more surface area. - therefore more places for active precious metal sites.
- The catalyst is added to the wash coat before applied it to the core.
Platinum is the most active catalyst and is widely used.
Other
material such as Palladium and
rhodium also been
used.Slide7
d) Catalytic Converter diagramSlide8
Types
Three-ways
Reduction of nitrogen oxides to nitrogen and oxygen:
2NOx → xO2 + N2
Oxidation of carbon monoxide to carbon dioxide:
2CO + O2 → 2CO2
Oxidation of unburnt
hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + 2xO2 → xCO2 + 2xH2O
Two-ways
Only treat carbon monoxide and
unburnt
hydrocarbon.Slide9
Oxidation Catalysts -Oxidation catalysts may be fitted to either petrol or diesel cars. -The catalyst oxidises
is effective at pollutants formed by incomplete combustion to carbon dioxide and water, and also for hydrocarbons,
aldehydes
and carbon monoxide. However, they do not reduce
NOx
emissions.Slide10
Negative aspects
Restriction to the flow of exhaust will cause negatively affected vehicle performance, and fuel economy.
Although catalytic converters are effective at removing hydrocarbons but most of the release gas through it is carbon dioxide (CO
2
).
Theft
- external location -valuable metal (platinum, palladium, and rhodium)Slide11
ConclusionT
he
catalytic converter is a great thing to have on a car because of its ability to help save the environment from those harmful
gasesSlide12
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