With the emission standards for diesel engines being implemented throughout the world, the fuel driving the engines receives little notice when compared to the extensive exhaust changes seen on the engines themselves.  Ultralow sulfur diesel fuel is certainly a critical factor in allowing after-treatment exhaust in meeting the particular reduction in emissions for all diesel equipment.

 

The ultralow sulfur fuel was first made widely available in 2006, since then nearly all petroleum-based diesel fuel available in the UK, Europe and North America is of a ULSD type.  Initially, there had been no standard established for defining the requirements for the designations of low or ultralow sulfur. The industry has since defined the criteria for ultralow as 15ppm sulfur content.  The standard for low sulfur has been set 500ppm, but is no longer an option for most applications. 

 

A drawback to ULSD fuel is that it has a lower energy content which means lower fuel economy (~1 to 2%), engines also must use more costly oil.  The usage of ULSD fuel has been implemented in most applications, but is of note today because as of December 1, 2014 all highway, non-road, locomotive and marine diesel fuel produced and imported must be ULSD.

 

ULSD, although more costly (~$0.05 to $0.25/gallon) and less fuel economic, allows diesel engines to meet the clean air initiatives and for after-treatment exhaust systems to be a viable maintainable method for the long life benefits of diesel fueled equipment.