DEF usage

According to Cummins (who makes the aftertreatment), DEF usage went from 2% to 4-5% on 2015+ engines. Both Cummins and Paccar both claim an equal increase in fuel mileage, so the operating cost should stay the same. No way to adjust DEF usage.

 

DEF is a scam. I can almost guarantee it's using more because the engine is tuned to use more so drivers/owners have to buy more. Especially if the dealership is saying that significant of drop in economy is "normal" you know they are in on it.

 

Wearing your tin foil hat today?

 

You bet.

 

Hahaha! Touché!

 

Guys guys....

DEFs sole purpose is NoX emissions reductions. It also helps with passive regen.

That said;

A diesel engine with higher fuel injection timing produces higher NoX , a side effect of Efficient diesel combustion.

The newer engines are squeezed harder on timing and use less EGR flow to hit the better fuel MPG numbers........side effect is NoX.

The NoX must be scrubbed to stay EPA legal.....thus they need more of the neutralizing agent = DEF/UREA


Using higher DEF is a GOOD thing knowing the working of your engine......, it's tuned more like a older engine (higher timing, injector split ratios) behind the scenes because they can effectively neutralize the "bad" emissions now with a spray of DEF.



I would NOT want them to reduce DEF consumption.... because that's 100% gonna come with reducing injector timing , increasing EGR and reduced MPG. NO THANKS.