Formaldehyde Emissions of Gasoline Mixed with Alcohol Fuels and Influence Factors

Alcohol fuels, including methanol and ethanol, are commonly mixed with gasoline. This paper designs the collection device for testing concentrations of formaldehyde emissions. Results indicate that compared with RON93 gasoline, formaldehyde emissions of M15, M25 and M85 respectively increase 7.2%, 26.5% and 46.6%, and those of E10 and E25 respectively increase 22.2% and 32.8%. Three way catalytic converter, test time, ignition advance angle and excess air coefficient have significant impacts on the formaldehyde concentrations. Two three-way catalytic converters will decrease the formaldehyde emission; the emission decreases with the test time and after ten minutes it tends to be stable; at 30% opening and 2600r·min-1, 25°CA before TDC corresponds to the lowest formaldehyde emission; excess air coefficient should be controlled near 1.