Sampling Conditions for Measurement of Formaldehyde from Methanol-Fueled Vehicle

Sampling conditions for the measurement of formaldehyde from methanol fueled vehicle were examined. A spike-recovery test was conducted for this purpose. The influences of CVS heating system were examined by a improved formaldehyde injection system.

When the duct temperature is in the range of 80 °C-130 °C, the recovery rate was 90 % or more. But when the duct temperature was low, the recovery rates reduced and part of the spiked formaldehyde remained on the duct. It was proved that low duct temperature or much quantity of moisture in the exhaust gas increased the rate of hang-up. Heating of the dilution air was effective in improving the recovery rate.

As a result of the formaldehyde spike-recovery test in the FTP mode, recovery rate reached 90% using appropriate conditions of CVS system.