A Review on the Impact of Bio-Additives on Tribological Behavior of Diesel Fuels

Table 1

Requirements for sulfur content in diesel fuels for on-road transportation [29].

Fuels	USA		Australia
	Sulfur content	Year	Sulfur content	Year
Diesel fuel	5,000 ppm	Until 1993	5,000 ppm	Before 2002
Low-sulfur diesel fuel	≤500 ppm	1993	≤500 ppm	2002
Ultralow-sulfur diesel fuel	≤15 ppm	2006	≤50 ppm	2006
—	—	—	≤10 ppm	2009