Emission Standards and Primary Measures for Reduction of Engine Emissions

1 Emission Standards and Primary Measures for Reduction of Engine Emissions 

During recent years, emission legislation has tightened significantly in Europe, the USA and in Japan (Table 6.18.2). Other countries have already adopted these regulations, for example, India and China follow European regulations with a certain time delay. 

Thus A, is a measure of how far from stoichiometry a mixture is. For A, 1, we have a fuel lean (oxidizing) atmosphere, and for A 1 a fuel rich (reducing) atmosphere. With increasing A, the CO and HC emissions decrease as more O2 is present for combustion. For NO, the emissions go through a maximum for a A-value of about 1. Under fuel-rich conditions (A 1), the amount of O2 is low and NO formation decreases, and under fuel-lean conditions the temperature drops, which also leads to decreased NO formation although O2 is present in excess. 

Primary methods to reduce the emissions from cars are (Moulijn, Makkee, and 

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