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2.7.3 System Working Principle
2.7.3.1 System Working Principle
Inside the three-way catalytic converter, the ceramic substrate
exposed to emissions is coated with a catalyst. Catalysts
containing platinum, palladium and rhodium, three kinds of
precious metals. These catalysts promote chemical reactions.
Catalyst is to accelerate the chemical reaction while remain
unchanged itself. Engine exhaust contains carbon monoxide
(CO), hydrocarbons (HC) and nitrogen oxides (NO
exhaust gas flows through the ceramic substrate, the chemical
reactions in the three-way catalytic converter occur. Carbon
monoxide and hydrocarbons is oxidized by the oxygen in the
exhaust gas (O
) and turned into carbon dioxide (CO
2
water vapor (H
O). Nitrogen oxides and carbon monoxide
2
through the reduction reaction, was converted into nitrogen
(N
). This three-way catalytic converter is called three-way
2
type, because it turns the three components (CO, HC and
NO
) into harmless neutral gas at the same time.
X
). When the
X
) and
2
Exhaust System JL4G18-D
EC718/EC718RV EC715/EC715RV 10/2009
2-431
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