Particulate Matter and Particle-Bound PAHs Emissions from Gasoline Direct Injection (GDI) Engine with Methanol-Gasoline Blended Fuel During Start

The effects of coolant's temperature on emissions of particulate matters (PM) and particle-bound polycyclic aromatic hydrocarbons (PAHs) from a gasoline direct injection (GDI) engine were studied during the start process using gasoline (M0) and gasoline mixed with methanol in 15 % volume (M15). The engine worked at a certain idle speed automatically under different coolant's temperature conditions after successful start. The experimental data was recorded from 0 to 40 seconds during the start. Results indicated that, there are significant differences in PM and particle-bound PAHs emissions between cold and warm start conditions. Particulate size distribution was measured with the Engine Exhaust Particle Sizer (EEPS) 3090. Compared with M0 fuel, the PM emission of M15 fuel decreased significantly, especially nucleation-mode particulate emission. The mass emission of PM was measured using the Gravimetric method. A same variation trend in PM mass emissions can be inferred for both fuels, i.e. it decreases while the coolant's temperature increases. Compared with M0 fuel, the PM mass with M15 fuel reduces by 80 % at 20 oC coolant's temperature. Agilent 7000B GC-QQQ was used to provide both qualitative and quantitative analysis on PAHs. The application of M15 fuel reduces the concentrations of most PAH species compared with M0 fuel, except those with smaller aromatic rings. In addition, Benzo(a)pyrene equivalent toxicity (BEQ) is calculated to evaluate the toxicity of PAHs emissions. The toxicity decreases when the GDI engine starts with higher coolant's temperature or with M15 fuel.