Is DEF that bad?

[Atypical_decorum]

Is DEF/DPF that bad?

Things I've heard:
1. If you don't run wide open long enough the back pressure from the soot buildup will damage engine.
2. DEF damages stuff when it leaks.
3. Engine stays choked for power.
4. All the crud is burned out eventually making the system essentially useless... Like poopin in a bag and saying you're not pooping, then dumping it later.
5. Prone to failure.

As most of us have, I'm considering a tractor with DEF. But I'm nervous about it because the EPA doesn't usually change things for the better or care about the end product at all.

 

[CloverKnollFarms]

Sounds like you are mentioning DEF and DPF. One reason I chose a mechanical injected tractor, the DPF is an accessory, and not integrated into the operation of the engine. I think most DPF issues are user error however.

 

[sea2summit]

DEF and DPF both add failure points. DPF does burn an engine faster if it works properly, if it works improperly it destroys the engine quickly or set your vehicle on fire depending. DEF adds a lot of complexity, in many ways it stops user maintenance of the engine because of the complexity of the system. If you can avoid it great, but that's getting harder and harder to do as older nice tractors become harder to find.

 

[jeff9366]

Diesel exhaust fluid​

Wikipedia
https://en.wikipedia.org › wiki › Diesel_exhaust_fluid




Diesel exhaust fluid (DEF; also known as AUS 32 and marketed as AdBlue) is a liquid used to reduce the amount of air pollution created by a diesel engine generating 75-horsepower or more.

DIESEL PARTICULATE FILTERS​

Stricter Tier IV off-road diesel engine emission reduction standards phased in dealer tractor inventory during 2009 - 2012, impacting tractor prices.

Tier IV emission standards require tractor manufacturers to add or revise pollution reduction technology on new tractors generating over 19 kW power = 25.4794 horsepower.

A Diesel Particulate Filter (DPF) is used by the majority of tractor manufactures for emissions control on OVER 24.4794 horsepower tractors.

Tier IV technology complicates the engine and exhaust package and is a significant cost factor. The pollutants emitted by a TierIV technology tractor are about 1% of the pollutants emitted by a pre-Tier IV tractor.

Diesel Particulate Filter (DPF) captures exhaust particulates (soot) in a ceramic matrix. When tractor engine runs sufficiently hot, accumulated particulates burn off periodically without operator intervention. If engine is not run continuously hot long enough to burn off particulates, diesel soot accumulates in the matrix. Once heavy soot accumulates in DPF the tractor forces soot clearance with the tractor parked and throttle open to about 2,200 rpm for about sixteen minutes, which makes the DPF REALLY HOT to burn off all accumulated soot. Burning off accumulated soot, either during operation or parked is called REGENERATION.

 

[jeff9366]

Is DEF/DPF that bad?

Regeneration is an infrequent DPF event with my Kubota three cylinder, 37-horsepower engine. Generally once every sixty engine hours. (Very consistent in Florida due to warm weather.)

60 hours X 60 minutes = 3,600 minutes.

16 regeneration minutes /3,600 = .00444 = 4/10s of 1% of engine time is consumed during parked regeneration.

Fuel cost for sixteen minute parked regeneration @ 2,200 rpm ~~$1.00.

Forty percent of my regenerations occur during operation, sixty percent parked.



The average residential tractor operates eighty engine hours per year, according to industry surveys.

3,000 hours DPF Life / 80 hours = 37.5 years of residential use prior to DPF replacement.

Diesel Particulate Filter supersedes tractor muffler.
At some point in time DPF needs to be replaced.
At some point in time tractors with mufflers need the muffler replaced.

 

[ruffdog]

Is DEF/DPF that bad?

Things I've heard:
1. If you don't run wide open long enough the back pressure from the soot buildup will damage engine.
2. DEF damages stuff when it leaks.
3. Engine stays choked for power.
4. All the crud is burned out eventually making the system essentially useless... Like poopin in a bag and saying you're not pooping, then dumping it later.
5. Prone to failure.

As most of us have, I'm considering a tractor with DEF. But I'm nervous about it because the EPA doesn't usually change things for the better or care about the end product at all.

What tractor are you considering? What size?

 

[ruffdog]

There are many ways and combinations of exhaust control/treatment.

SCR,DEF, DPF, EGR | FCAR Tech USA

 

[Atypical_decorum]

What tractor are you considering? What size?

I'm looking at a JD 5085EL

 

[ruffdog]

It looks like the jd 5085e uses EGR, DOC (DPF), and SCR (DEF). The biggest issue with DEF is the quality of fluid without contamination. Just like with everything, if we knew the history of the tractor, we could make an informed decision.

https://www.deere.ca/en/products/tr...amily-utility-tractors/5085e-utility-tractor/

 

[rockinbbar]

I've had a 100hp tractor with a DPF. I run hard, so the DPF did it's job, and in 10 years, I never had to replace the DPF. I didn't just poot around doing short chores on that tractor.

Now, fast forward 10 years and I traded the previous 100hp tractor in on a new 120hp tractor with the same engine, but it uses DEF and has no DPF.
Tractor runs great, no loss of power, no extra fuel burned when the DPF comes on, because it doesn't have one. Only uses DEF when it needs it, according to how I use the tractor.

Funny thing is, my new 120hp tractor uses LESS fuel in a day's time than my previous 100hp did. I attribute that to not having a DPF.

Given the choice, I'd pick a tractor with DEF over a tractor with a DPF.

Was operating that older tractor after dark once when the DPF came on, and the whole exhaust pipe was so hot when it was regening, it was glowing red. That has to be hard on the entire exhaust system.

Some DEF systems had sensors corrode and go bad, forcing the equipment into "limp" mode until the sensor was replaced. This caused a huge shortage of sensors world wide for many manufacturers. Nothing wrong with the system or the DEF in most cases. Just the bad sensors that would corrode and throw false readings. But it appears the later sensors are much less corrosive, and are standing pretty steady now.