Basic investigation of particulate matters (O-PM) and polycyclic aromatic hydrocarbons emitted by two-stroke motorcycles

摘要

Characteristics of mass emission of unburned Oil-Particulate Matter and polycyclic aromatic hydrocarbons from two-stroke scooter were investigated. The tests were carried out with and without oxidation catalyst and various air-fuel ratios ranging from 12 to 16 at 50:1 of fuel-oil mixing ratio for easy sampling. Unburned Oil-Particulate Matter and 4- to 7-rings polycyclic aromatic hydrocarbons were trapped on filter. These compounds were analyzed by high-performance liquid chromatography with fluorescence detector. Mass emission of polycyclic aromatic hydrocarbons and unburned Oil-Particulate Matter tends to decrease as air-fuel ratio which increased up to stoichiometric ratio. The highest conversion ratio of unburned Oil-Particulate Matter on the oxidation catalyst was 64%. Conversion ratio of polycyclic aromatic hydrocarbons increased as rings are smaller. However, in one case of this test, some of 5-rings aromatic hydrocarbons or higher compounds showed a tendency to increase by the oxidation catalyst.