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The Emission Control System:
Air Injection
The air injection system reduces carbon monoxide and hydrocarbons by eliminating residual fuel vapor as soon as it exits the engine. The air injection system adds fresh air to exhaust as it exists the engine. By adding a small amount of outside air, residual fuel vapors are allowed to continue to burn as they travel through the exhaust manifold toward the catalytic converter.
Catalytic Converter
 Although some of the carbon monoxide is converted to carbon dioxide in the exhaust manifold, there are still numerous poisonous gases present in exhaust. The catalytic converter uses catalysts to neutralize these gases. Catalyst is just a name for something that causes a chemical reaction without neutralizing itself. Your catalytic converter is lined with catalysts like aluminum oxide and platinum that react to the harmful gases found in exhaust and changes them into water vapor, nitrogen and carbon dioxide.
Converter Operation
Catalytic converters basically function like a furnace. As hydrocarbons (HC) and carbon monoxide (CO) enter the catalytic converter they are drawn through the honeycombed block of catalyst.  As the gases pass through the converter, they react to the catalyst and burn at extreme temperatures. In fact, it is common for temperatures to burn in excess of 1300 degrees Fahrenheit. The intense heat ignites the emissions and changes their chemical properties into water and harmless carbon dioxide.
After harmful emissions are ignited and neutralized, the exhaust exists the converter, traveling through more pipe and enters the muffler.
Construction
There are a couple of types of catalytic converters. Older versions tend to use small ceramic beads that were coated with catalyst substances and encased in a stainless steel housing. Automobile manufacturers have since switched to honeycombed catalyst blocks. These newer models have a honeycomb design that routes exhaust through long passages that run through the core of the catalyst. Honeycombed designs consist of either one large block of catalyst or the catalyst is divided into two separate blocks, called a dual-bed catalytic converter.
One key advantage of The honeycomb design is that it provides a great deal of catalyst surface area upon which the exhaust can act upon.
The dual bed converter uses injected air to help burn pollutants during the process.
Converters are comprised of two catalyst blocks. The first converter is called the reduction catalyst. Reduction catalyst primarily attack NOx emissions by stripping away |
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Article Pages
1. Emission Control
2. Types Of Pollutants Created By Your Engine
3. 6 Ways In Which Emissions Are Reduced
4. Exhaust Gas Recirculation (EGR)
6. Evaporation Emissions Control Systems (EVAP)
7. Positive Crankcase Ventilation (PCV)
8. Automotive Emissions Wrap Up
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