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Theoretical evaluation of carbon monoxide and hydrocarbon reduction by secondary-air injection

✍ Scribed by Toshimi Takagi; Kenichi Fujii; Mitsunobu Ogasawara


Book ID
103090942
Publisher
Elsevier Science
Year
1975
Tongue
English
Weight
626 KB
Volume
54
Category
Article
ISSN
0016-2361

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✦ Synopsis


In order to evaluate the effects of various factors upon the performance of a thermal reactor with secondary-air injection which reduces carbon monoxide (CO) and hydrocarbon emitted from combustion engines, analytical studies were carried out for a model in which one-dimensional flow of gas is assumed. Effects of factors such as gas temperature, injection rate of secondary air, residence time and air/fuel ratio of the engine have been examined by chemical kinetics, taking 20 chemical species and 52 elementary reactions into consideration.

The oxidation rate of CO and methane (CH4) becomes high when the gas temperature after air injection exceeds about 900 K. For a given gas temperature, there exists an appropriate range for the quantity of injection air in which CO, CH, and formaldehyde can be reduced effectively. This range can be widened by either raising the gas temperature or prolonging the residence time. By increasing the air/fuel ratio of the engine, CO and CH, emitted from the reactor tend to decrease. These results explain reasonably well the phenomena formerly observed experimentally.