2014 Mack CHU613 DEF usage

there is Volvo D11 ore D13 engine under hood. DEF usage is from 3 to 10% of fuel usage. Really on newer engines they use NOx sensor and DEF usage depends on temperature, engine load, fuel quality, EGR operating so it varies. When NOx sensor goes bad it reads "dirty exaust" and SCR uses more DEF till power derate is on (it is time to change NOx sensor).

SCR requires some maintanace, you have to change DEF filter and sometimes heated lines go bad. Do not let truck sit for too long time to avoid crystalisation and save DEF pump

 

surelly 1% is impossible.

The biggest DEF usage was on Euro-5 w/o EGR trucks. Non EGR engine emmits too much NOx so early E5 used 8% of DEF. So Volvo installed EGR valves to reduce NOx and save DEF.... but EGR makes soot and that's why they use DPF + DOC..... so we have all emission stuff in one and it is called Euro-6/EPA2012

 

I haven't taken the time to break it down by truck but each of mine will use about $80 worth of DEF or about 100 litres as there can be a big difference (30%) in prices on where you buy it. I average around 5-5.5MPG pulling Super B Cement Bulkers but have never taken the time to calculate a percentage of fuel. I run about 15,000km a month on each truck though.

 

2011 DD15 515hp....was getting 245 mpg of DEF..
After the system was worked on under warranty,160 to 175 mpg...

 

some operators here make DEF. they use carbomide from farm store and distilled water)))) But mixture must be well filtered