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I would like to know what mechanical items on a automotive vehicle effect emission gases, such as: causes high hydrocarbons, nitrogen oxide, and carbon monoxide.

Perfect combustion of gasoline (or diesel) and oxygen should result in CO2 and H2O. However, there is rarely perfect combustion, not to mention that air (which contains mainly nitrogen and hence generates NOx's) is used, not pure oxygen. Some factors that bring about the pollution you mention is incomplete combustion of the fuel (which usually means not enough air in the fuel mixture), too much air in the fuel mixture, dirty fuel (due to bad distillation or oil in the fuel), misfiring of the spark plug (in gas engines) before complete compression of the fuel, and incomplete compression of the fuel mixture. These are just a few of the major causes.

The mechanical item that cause these conditions may include dirty fuel or air filters (less fuel or less air getting in, plus the chance of dirty fuel or air getting in), dirty carburetors (bad air fuel mixtures), dirty spark plugs (misfiring), bad piston rings (incomplete compression and oil seepage), and the timing is off (misfiring before complete compression). A majority of these problems are fixed during a tune up (spark plugs and wires, distributor caps, timing, etc.) and with routine maintenance (oil change, fuel and air filter change, etc.). Things such as pistons rings and carburetors may require more intensive maintenance. Rule of thumb to reduce emissions: Keep you car in good running condition by maintain it per the automotive company's schedule.


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