Final Tier 4 Engines, diesel exhaust fluid (DEF) and Ultra-Low Sulphur Diesel (ULSD)

Category: News
September 5, 2018 cosmick

As “we” (Hydra-Tech Pumps and our customers) make the transition to Final Tier Four engines through the end of 2018 we wanted to put some important information in front of you.  There are two key things that you need to know as you begin to operate and maintain hydraulic power units with Final Tier Four engines as their power plant.

Ultra-Low Sulphur Diesel (ULSD)

Final Tier Four (for that matter Interim Tier Four as well) diesel engines require Ultra Low Sulphur Diesel – to be clear the fuel must contain less than 15 parts per million of Sulphur.  Anything above this level will impact the performance of the engine and its ability to operate.

Generally speaking, ULSD has been available in the United States and Canada since it was widely introduced in 2006.  So for our domestic customers and those in Canada, there is not much concern about running non-ULSD through a Final Tier Four engine.  There is a map that updates on a monthly basis the diesel fuel Sulphur levels in every country around the world – this is a nice resource for our international customers who might want to see what the diesel fuel Sulphur content levels are in their country.  Check out

Diesel Exhaust Fluid (DEF)

Diesel exhaust fluid is a liquid solution comprised of 32.5% urea and 67.5% deionized water that is used in the exhaust after treatment system on Final Tier Four industrial engines of 75 horsepower or higher.  Basically it is injected into the exhaust pipeline to eliminate nitrogen oxides which are harmful pollutants.  The requirement on us as a manufacturer of hydraulic power units is that the DEF tank contain an appropriate volume as a ratio to the fuel capacity.  If our HPU has a 100 gallon diesel fuel cell then the DEF tank will need to hold 3-4% of that volume, or 3-4 gallons of DEF – there is some variation of the ratio from one engine manufacturer to another.

As you begin to build Final Tier Four engine based hydraulic power units (and other equipment) into your fleet, make sure that you are filling the fuel cells with Ultra-Low Sulphur Diesel and topping off the DEF tanks!