A catalytic converter is an emissions control device that converts toxic gases and pollutants in exhaust gas to less toxic pollutants. The catalytic converter was invented by Eugene Houdry, a French mechanical engineer and expert in catalytic oil refining. In the catalytic converter, there are two different types of catalyst at work, a reduction catalyst and an oxidation catalyst.
Emission Control by Catalytic Converter, Jeevan B M
VEHICLE EMISSION CONTROLE BY CATLYTIC
Jeevan B M
2nd SEM Automotive electronics
SJCE, Mysore 1
• Construction of catalytic converter
• Working of catalytic converter
• Types of catalytic converter
• Advantages and disadvantages
• Electronic emission is a substance discharged into air,
especially by an internal combustion engine.
• Vehicular emissions include a number of biologically active
substances such as CO, HC and NOx.
• These air pollutants are responsible for a number of adverse
environmental effects such as photochemical smog, rising
mercury, acid rain, death of rain forests, health hazards and
reduced atmospheric visibility
• Vehicle emissions control is the study of reducing the motor
•There are mainly three types of vehicle emission
control they are
oExhaust gas recirculation
•A catalytic converter is an emissions control device that
converts toxic gases and pollutants in exhaust gas to less
•A catalytic converter provides an environment for a
chemical reaction wherein toxic combustion by products
are converted to less-toxic substances
• The catalytic converter was invented by Eugene Houdry, a
French mechanical engineer and expert in catalytic oil
• Houdry first developed catalytic converters for smoke stacks
called “cats” for short,.
• In the mid-1950s, he began research to develop catalytic
converters for gasoline engines used on cars
• Catalytic converters were further developed by a series of
engineers including John J. Mooney and Carl D. Keith at the
Engelhard Corporation, creating the first production catalytic
converter in 1973
• 1975 onwards started use these catalytic converters in fuel
• Three-way catalyst technology, introduced in the 1980s, made
it also possible to control NOx emissions from SI engines
•The core is often a ceramic honeycomb in modern catalytic
•The washcoat, when added to the core, forms a rough, irregular
surface, that surface area is utilized for catalyst reaction.
•The catalyst(Platinum) itself is most often a mix of precious
•Palladium(oxidation catalyst) and rhodium(reduction catalyst) are
two other precious metals used.
Working of Catalytic Converter
•In chemistry, a catalyst is a substance that causes or accelerates
a chemical reaction without itself being affected.
•In the catalytic converter, there are two different types of
catalyst at work, a reduction catalyst and an oxidation
•Both types consist of a ceramic structure coated with a metal.
•catalyst, usually platinum, rhodium and/or palladium.
Types of Catalytic converter
•Catalytic converters are classified into 2 types based on the
capability of eliminating the number of pollutants
oTwo-way catalytic converter
oThree-way catalytic converter.
Two-way Catalytic converter
• The two-way oxidation catalytic converter performs two
simultaneous tasks of oxidation of carbon monoxide to carbon
dioxide and oxidation of hydrocarbons to carbon dioxide and
• Oxidation of carbon monoxide to carbon dioxide:
CO + O2 → 2CO2
(carbon monoxide) (oxygen) (corban-di-oxide)
• Oxidation of hydrocarbons (unburned and partially burned fuel)
to carbon dioxide and water:
CₓH₂ₓ₊₂ +[(3x+1)/2] O2 → xCO2 + (x+1) H2O
Hydrocarbon (oxygen) (carbon-di-oxide) (water)
• Disadvantage: inability to control oxides of nitrogen
Three-way Catalytic converter
• It converts harmful gases(Nox, co, HC) in the engine
exhaust to relatively harmless gases(N2, Co2, H2O).
•A three-way catalytic converter makes use of two catalysts to
convert harmful gases to harmless gases. They are
oReduction Catalyst(platinum and rhodium)
oOxidation Catalyst(platinum and palladium)
• Stage 1
2NO → N2 + O2
(oxides of nitrogen) (nitrogen) (oxygen)
Stage 2:in this stage oxidation occurs as in two way
• 3-way catalytic converters are so named because they are
capable of eliminating three pollutants – NOx, CO and HC
Advantages and Disadvantages
o Reduce the amount of harmful pollution produced by the
o Faster reactions
o Easy replaceable
o Decreased horsepower-engine uses more energy for the
o Catalyst require some time to start its action
o they are very expensive to get
•Vehicular emissions produces the CO, HC and NOx these
emission are reduced by using catalytic converters.
•The two-way oxidation catalytic converter that are reduces
the effect produced by CO,HC.
•The three-way oxidation catalytic converter that are reduces
the effect produced by CO,HC and Nox,
•catalytic converters are play a major role in reduction of
emission produced by the vehicles.
Air injection and Catalytic converters by Matthew Whitten
Catalystor.pdf that gives complete information.
emissions control devices.
emission by vehicle
Mechteacher.com-gives information about the three way