Particulate Matter Emissions from a Flexfuel Gasoline Direct Injection Vehicle 2015-36-0401
Gasoline direct injection (GDI) vehicles are considered to be one of the solutions for engine optimization with regard to fuel consumption. This combustion system potentially provides, depending on the duty cycle, an improvement in fuel economy of 5 - 10%. In Brazil, mainly due to new requirements to reduce consumption imposed by the Inovar Auto automotive regime, this technology is becoming more popular and in 2013 the first flexfuel GDI vehicle was produced. However, GDI engines tend to produce more particulate matter compared to conventional engines. The present article is based on the study of particulate matter emissions from a GDI vehicle tested according to the FTP75 (Federal Test Procedure 75) and HWFET (Highway Fuel Economy Test) cycles. The vehicle was fuelled with gasoline (A22) and with hydrated ethanol (HER). It was observed that the particulate matter formed after the combustion process is directly related to the fuel properties. Moreover, when the vehicle is fuelled with A22, the particle size tends to be ten times smaller compared to HER. The results indicate that the particles adhered to the filter size around 2 microns and its composition revealed that they have higher concentrations of fluorine and carbon and minor amounts of silicon and oxygen compared with a baseline. It was also observed in most filters one agglomeration of particles with sizes smaller than 0.5 microns. Regarding the total PM mass it was observed that emissions from A22 gasoline exceed the ones from HER. It was also observed that PM emissions from HWFET cycle are higher compared to the FTP 75 cycle.