Aldehydes and Methanol Emission Mechanisms and Characteristics from a Methanol/Gasoline-Fueled Spark-Ignition (SI) Engine

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• 作者：Yanju Wei ; Shenghua Liu ; Fangjie Liu ; Jie Liu ; Zan Zhu ; Guangle Li
• 刊名：Energy & Fuels
• 出版年：2009
• 出版时间：December 17, 2009
• 年：2009
• 卷：23
• 期：12
• 页码：6222-6230
• 全文大小：1132K
• 年卷期：v.23,no.12(December 17, 2009)
• ISSN：1520-5029

文摘

Formaldehyde (HCHO), acetaldehyde (CH₃CHO), and methanol (CH₃OH) emission characteristics as well as their conversion efficiencies on the three-way catalytic converter (TWC) were investigated on a three-cylinder, spark-ignition (SI) engine when it ran on gasoline and M85 (gasoline/methanol = 15:85), respectively. In addition, their emission mechanisms were simulated on a plug flow reactor (PFR) model with the detailed kinetic mechanism of primary reference fuels as well. Simulation results show that there exist contribution zones for both HCHO and CH₃CHO emissions in pipes along with decrescent temperatures; it contains two subzones of the generation zone (Z_G) and the following generation−consumption zone (Z_G−C). Aldehydes emissions become the peak value at the critical point, and the critical temperature of HCHO is higher than that of CH₃CHO. The increase of the initial temperature and residence time of the gases in the pipe will move the aldehydes emissions from Z_G to Z_G−C along the emission profiles. The initial temperature of the exhaust pipe lies between the critical temperatures of HCHO and CH₃CHO; thus, the HCHO emission decreases while the CH₃CHO emission increases with the increase of the engine torque, i.e., initial temperature. With the increase of the engine speed, the decrease of the residence time takes the dominant role, the HCHO emission increases, while the CH₃CHO emission decreases. However, the initial temperature in TWC is higher than the critical temperature of CH₃CHO; the aldehydes conversion efficiencies decrease; and minus efficiencies appear at high engine speeds. Simulation results coincide well with the emission characteristics.