DPF fuel consumtion

[Boehmer]

I have been trying to research and determine if there is some avg or correlation I can find between the amount of DEF fluid to Diesel fuel used during Diesel Particulate Filter regeneration. I understand that there are numerous variables involved such as driving conditions, driving habits, active vs passive regen........ I have read a lot of Cummins literature and talked to Cummins people on the phone. Most of what you find relates to the Amount of DEF used during regeneration but I cant seem to find much to rely on regarding diesel fuel used. I did get a Cummins rep back in 2018 to give me the following info:

4 to 5 gallons DEF** used per 100 gals of diesel in the tractor for 2013 and new semis.

** you can expect to burn about 10% of this number for fuel burn.


So in other words, if you know your gallons of DEF used, you should be able to take 10% of that number to arrive at an estimate of the diesel fuel used for regen.

Any input, thoughts, references or documentation that will either support this or shed some light on this is appreciated

[Rawze]

The engine control module for in the engine records where all the fuel and DEf fluid is going, right along with the mileage and engine hours.


Things like ...

- Total Lifetime DEF-to-Fuel Ratio. - A percentage of DEF fluid vs., fuel consumed over the lifetime of the engine.

- Total Lifetime Fuel consumed. - The total amount of fuel consumed by the engine and its aftertreatment systems combined.

- Total Doser fuel used. - the total fuel that has been consumed by the Aftertreatment system over the lifetime of the engine.

- Total HC used. - The total fuel DEF fluid that has been consumed by the Aftertreatment system over the lifetime of the engine.

- Total Idle fuel consumed. - The total fuel consumed whole idling stationary for the engine.

- PTO Total Fuel used. - the total fuel consumed for any PTO operations for the engine over its lifetime.

- and of course,.. total engine hours.. total miles, and other things, etc., etc.

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To get an average of what trucks generally do ... it would also have to focus on what type of trucking operations as well.

Someone would have to collect this data across many trucks within a single sector and compare them.

What I mean is that all the data would depend heavily on what type of trucking operations. A highway truck is clearly not going to idle nearly as much as a city truck. And many trucks have PTO operations ... which would show very different consumption rates., etc.

A car hauler truck is NOT the same as a local cement mixer, or garbage, or highway truck. Their use of fuel, DEF, and everything else are all going to be VERY different from each other.

There is no 'x%' of DEF vs fuel standard, because trucking operations vary so widely. .. and any person that would tell you such ballpark numbers are nothing but regurgitating what a typical salesman would say at the local stelaers%it.

[JimT]

Just to add, DEF is used to reduce NOx emissions, while the DPF's purpose is to catch and burn soot. EGR was, and still is, the primary way these engines attempt to control NOx (along with lower engine RPM's) by reducing the combustion temperature and as a result the exhaust temperature. The DEF is secondary when the NOx levels are still too high to meet the newer requirements. While it's true that regens for the DPF will result in increased NOx output, it's not the only factor. The amount of fuel burned and the amount of DEF needed to reduce NOx can, and will, vary depending on engine condition, operation and efficiency. Tracking the relationship between EGT's and DEF usage might be more consistent than the relationship to fuel, but I'm not aware of a way to do that.

Even narrowing it down to DEF used only during regens, as you mentioned, can and will vary wildly depending on type of regen, soot load at the time of regen and efficiency of the DOC and the regen.

Looking back at my fuel/DEF records, it seems I pumped about 5 gallons DEF for every 300ish gallons of fuel. Though it wasn't an exact relationship between the two. As Rawze said, you could probably find common averages based on segment/usage characteristics and of course an over all industry average. But it would only be an average and wouldn't be accurate for any specific truck. It's like saying the average family has 2.4 kids (or whatever), it doesn't have any relevance to the individual.

[Boehmer]

I know that there are a lot of variables that need to be considered and I understand that a lot of this data can be downloaded from the trucks ECM but I was hoping to get more support or info on this in dealing with the IRS. I work on fuel tax related issued with about 100 trucking companies. There are fuel tax credits that can be pursued based on the diesel used during these DPF regenerations (nontaxable use). It is too difficult and cost prohibitive for these companies to bring their trucks in to have this data downloaded every quarter. We have been using the data given to us from Cummins on this from about 5 years ago. Its nothing more than a response to an E-mail I sent to them. The issue is coming under more scrutiny lately and I was hoping to get some type of supporting information that would back up our 10% diesel to DEF ratio. Not looking for specifics just something that would give some industry average. Regardless if that average applies to my clients or not. I need to find something to use.

[tree98]

Sounds like a good way to be under constant scrutiny for only a few measly dollars in return. I wouldn't bother with that hornets nest if I were you.

[Rawze]

Last I checked.. ALL FUEL that is poured into the tanks of the truck is tax deductible by the purchaser, and is therefore a business expense... right along with any taxes paid on that fuel at the time of purchase too.

[Boehmer]

(03-19-2024 )Rawze Wrote:  Last I checked.. ALL FUEL that is poured into the tanks of the truck is tax deductible by the purchaser, and is therefore a business expense... right along with any taxes paid on that fuel at the time of purchase too.

Yes all fuel is deductible. I am working with trucking companies to get back the federal tax of .244/gallon paid on the diesel fuel

[tree98]

Hmm this doesn't really make any sense.
Let's assume a truck uses 1 gallon of fuel during a forced regen and the driver is doing a forced regen on every single truck in the fleet once a week because the company is so stupid and ignorant they can't maintain them properly. Now let's say you own 100 trucks. 24 cents times 100 trucks is only $24.00 per week or $1,248.00 a year.

And before you say " what about the fuel used for passive regen while driving down the road" there's no easy way your going to be able to differentiate between fuel used for propulsion and fuel used for regen. And certainly not by some blanket formula based on made up averages.

Using a diesel to DEF ratio like you mentioned is totally useless because there are numerous reasons why one truck would use much more fuel or DEF than another one and that could change at any given time depending on many factors.

If what your proposing is even legal ( I haven't checked into it) I can guarantee you'll be watched like a hawk and likely audited perpetually over it. Is all the paper work and headache really worth a few measly dollars??

If someone is losing so much money to fuel tax on gallons used during regen, I would say their time is much better spent getting the trucks to run and operate correctly instead of trying some convoluted tax refund loophole jackassery.

[Rawze]

Here are my thoughts ...

For the single O/O .. or small fleets (only a few trucks) ...

Paying some ex$$$ CPA accountant to split all your expenses into spread sheets, monthly, weekly, quarterly, etc., and separating by every type of category known to man + all their individual margins, and all sorts of other nonsense that CPA bean-counter bullarky, is simply a complete waste of time, effort, and moneys.

Perhaps they might find a few dollars across the entire year... only for someone to spend 10x that much on the CPA services themselves, .. and are in the end, no further ahead any ways.


I.E.> Most O/O's don't need a sophisticated CPA services ... only to get what?.. if they squeeze every last red extra cent ... maybe another $40 bucks (and that is being zealous) in obscure tax break(s), but only after they have wasted thousands$$$ on that same CPA's services, getting back all kinds of stupid/useless reports, that frankly, the IRS THEMSELVES could totally not give a damn about!?

Single truck and small fleet trucking is NOT that complicated. Here is all someone needs to know about Single O/O taxes ... saving themselves FAR MORE MONEYS by not hiring a CPA, but simply a tax professional one time a year for a hundred bucks or so instead...

Here is Rawz'e shade-tree tax advice... Works just fine for me...
http://rawze.com/forums/showthread.php?t...99#pid1699

- Sure, someone might be missing out on some very obscure $$$ amount of green energy garbage tax break moneys like "my regeneration fuel tax break" ... maybe even on a very bad year of constant regen issues and making it a VERY ZEALOUS couple hundred bucks savings ... but then spending 10x that amount on that CPA instead. I.E.> They are no further head.

- And for the fleets of thousands of trucks .. they always have their own in-house lawyers, bean counters, and idiots who would squeeze every last cent of profits for every imaginable creative way to screw the drivers out of their pay for stupid s$it like over-priced, garbage insurance with deductibles that are higher than the whole hospital bill would be if you simply paid cash... .. some trash 401k bulls#it, that profits the company for its investment into, all at the employees expense ... that also will never be collected on, and also to screw the warranty/abuse of the equipment, by not changing the oil or maintaining things to the last very edge of legality before truck failures occur. - This is how the mega-fleets make $$$ out of cheap freight.