Dosage rate indicates how much DEF is required compared to the amount of diesel fuel consumed. If the dosage rate is 2 percent for every 100 gallons of diesel fuel consumed, the truck will use two gallons of DEF.
The actual dosage amount will vary from one diesel engine manufacturer to another. It will also vary based on vehicle size, the stress placed on the motor, and idling time.
For a diesel pick-up, the normal DEF dosage is 1.5 percent, or 1.5 gallons for every 100 gallons of fuel consumed. A class 8 semi will usually vary between 3 to 8 percent, or 3 to 8 gallons of DEF for every 100 gallons of diesel consumed. Heavy off-road equipment, like a tractor trailor under full tillage, can get up to 10 percent DEF dosage. That means 10 gallons of DEF for every 100 gallons of diesel used.
How Can You Calculate Your DEF Dosage Rate?
As stated above, each engine will vary a bit on the amount of DEF fluid consumed. The best way to calculate how much DEF fluid your truck or heavy equipment will consumed is to run it for a while and track usage.
Fill the DEF reservoir at the same time you fill the diesel tank. Note the number of gallons of both DEF and diesel fuel. Next time you refill the diesel tank, top off the DEF reservoir. Note the gallons used of each. Divide the number of DEF gallons consumed by the number of diesel gallons used.
That is your dose rate. So, if you burned 300 gallons of fuel and consumed 6 gallons of DEF, the dose rate is .02, or 2 percent. By doing this a few times in a row, you can calculate, with some accuracy, the typical DEF dosage rate for your truck or heavy equipment.
Periodically checking the DEF dose rate is important. Any significant variations of DEF use can show a problem with the selective catalytic reduction system or another mechanical problem that affects the amount of diesel fuel consumed. Having both checked will keep the vehicle in good operating condition.
Managing DEF is an emerging part of fuel management. If you want to get some help with DEF or other fuel management issues, contact us here at Innovative Fueling Services.