Emission Characteristics of Fine Particles from Different Fuel Injection Mode Vehicles

In this paper, six light-duty gasoline vehicles meeting China VI emission standard were selected for cold start Worldwide Light-duty Test Cycle (WLTC) tests, including two vehicles with Port Fuel Injection (PFI), two vehicles with Gasoline Direct Injection (GDI) and two vehicles with Mixed Fuel Injection(MFI). A new condensing particle counter which can measure fine exhaust Solid Particulate Number in the particle size range of 10 nm–2500 nm (SPN₁₀) was used in conjunction with the condensing particle counter which can measure exhaust Solid Particulate Number in the particle size range of 23 nm–2500 nm (SPN₂₃) recommended by the China VI emission standard to simultaneously measure the Solid Particulate Number (SPN) of the test vehicles. And the total amount of particulate matter emissions (#/km) and transient emission (#/cm³) of light duty gasoline vehicles were obtained. The results indicate that the amount of particulate matters emitted by gasoline direct injection vehicles is higher than that of mixed fuel injection vehicles, and much higher than that of port fuel injection vehicles. However, the number of fine particles emitted by vehicles with particle size above 10 nm using port fuel injection technology is about 1.5 times that of particles emitted by vehicles with particle size above 23 nm. The reason for this phenomenon is that the port fuel injection technology will generate more sulfate, small particles of unburned hydrocarbon and other fine particle size. The total amount of particulate matter emitted by sub-vehicles with particle size above 10 nm cannot meet the recommended value of 1 × 10¹¹ #/km proposed by the European Commission League for Low Vehicles Emission (CLOVE). Therefore, it will be a trend for light-duty gasoline vehicles to be equipped with efficient GPF after the next stage of regulation is determined.