Effects of lubricant-fuel mixing on particle emissions in a single cylinder direct injection spark ignition engine.

Gasoline direct injection (GDI) engines emit less carbon dioxide (CO) than port fuel injection (PFI) engines when fossil fuel conditions are the same. However, GDI engines emit more ultrafine particulate matter, which can have negative health effects, leading to particulate emission regulations. To satisfy these regulations, various studies have been done to reduce particulate matter, and several studies focused on lubricants.