Compact Tractor Diesel Particulate Filters (DPF)

[jeff9366]

Time to evolve an educational thread on Tier IV (final) DIESEL PARTICULATE FILTERS.

Some form of soot/particulate removal technology is required on new tractors generating over 19 kW power = 25.4794 horsepower.

DPF is used by the majority of tractor manufactures, but not all.


I intend to develop this thread over time with contributor's input.

 

[jeff9366]

By this point we all know the general premise of how the DPF works... it captures soot in a ceramic matrix... and when hot enough it burns said soot off. If the soot builds up in the matrix to a certain point - then the tractor demands we run it parked for a period of time where it makes the whole DPF REALLY HOT (the process is called regeneration or regen) and then - the process starts over.

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.

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



Regeneration is an infrequent event for my Kubota three cylinder 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.



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.

 

[jeff9366]

Following summarizes cost to VW for exceeding diesel emission standards on their diesel engine cars. Not entirely germane, but somewhat so.

How much has Dieselgate cost Volkswagen?​

Dec. 23, 2018 5:33 AM ET​

|

About: Volkswagen AG ADR (VWAGY)|By: Yoel Minkoff, Seeking Alpha News Editor​

The cleanup of Volkswagen's (OTCPK:VWAGY) diesel cheating scandal will cost the automaker €5.5B in 2018, around €2B in 2019 and €1B in 2020, CFO Frank Witter told Boersen-Zeitung.

Since 2015, the German group has paid more than €27B to settle investor and consumer lawsuits, as well as regulatory fines and remedies tied to resolving excessive emissions levels in its diesel cars.

27,000,000,000 Euros = $23,700,000,000 $/US​

 

[TBone]

Thanks Jeff for an explanation of how the DPF works. I know my L2501HST doesn't have DPF but do you know if it has a computer?

 

[jeff9366]

No, I do not. Sorry.

 

[ericm979]

The 2501 uses mechanical fuel injection.

Bransons have a DPF but use mechanical injection rather than electronic like other tractors with DPF. It uses a low temp continual regen scheme rather than discrete regens with added diesel fuel. Low Temperature Diesel Particulate Filter Regeneration by Atmospheric Air Non-thermal Plasma Injection System | SpringerLink

A few Tier 4 tractors between 25 and 75 hp use DOC (Diesel Oxydation Catalyst) instead of DPF. Those have electronic fuel injection but no DPF and no regens. Mahindra is one.

The DPF or DOC is to reduce soot output. Diesel soot is tiny particles that can go way down in the lungs and don't get expelled from the lungs like larger particles. They can cause cancer and other health problems. Tier 4 also sets limits on other pollutants like NOx but at the under 75hp level those can be met by combustion chamber design and changes in injection timing. Interestingly, reducing NOx raises soot and vice versa. So the engine designer has to strike a balance.

Above 75hp the tier 4 requirements are more stringent and generally are met with a DPF and DEF (Diesel Exhaust Fluid) in an additional catalyst.

With a DPF tractor it's a good idea to run the tractor at the RPMs the manufacturer recommends most of the time and work it hard at times.

DPFs can be cleaned. Costs I've seen range from $300-600 but that's for on the road trucks. A CUT's DPF should cost less as it's smaller. If it's too clogged it may not be cleanable.

 

[JimR]

The 2501 uses mechanical fuel injection.

Bransons have a DPF but use mechanical injection rather than electronic like other tractors with DPF. It uses a low temp continual regen scheme rather than discrete regens with added diesel fuel. Low Temperature Diesel Particulate Filter Regeneration by Atmospheric Air Non-thermal Plasma Injection System | SpringerLink

A few Tier 4 tractors between 25 and 75 hp use DOC (Diesel Oxydation Catalyst) instead of DPF. Those have electronic fuel injection but no DPF and no regens. Mahindra is one.

The DPF or DOC is to reduce soot output. Diesel soot is tiny particles that can go way down in the lungs and don't get expelled from the lungs like larger particles. They can cause cancer and other health problems. Tier 4 also sets limits on other pollutants like NOx but at the under 75hp level those can be met by combustion chamber design and changes in injection timing. Interestingly, reducing NOx raises soot and vice versa. So the engine designer has to strike a balance.

Above 75hp the tier 4 requirements are more stringent and generally are met with a DPF and DEF (Diesel Exhaust Fluid) in an additional catalyst.

With a DPF tractor it's a good idea to run the tractor at the RPMs the manufacturer recommends most of the time and work it hard at times.

DPFs can be cleaned. Costs I've seen range from $300-600 but that's for on the road trucks. A CUT's DPF should cost less as it's smaller. If it's too clogged it may not be cleanable.

My local Kioti dealer told me Saturday to run my 45HP tractor at 1800 or better at all times to keep the filter from clogging. I have 350 hours on it and the tractor has only gone into regen once since I bought it 2 years ago. I did run the regen a few times recently to check the rpm problem that I was having. The dealer said my tractor only had 2% in the filter from a test that they ran last week.

 

[CMV]

That is great JimR! Mine goes about every 40 hrs. My dealer said 2000rpm, but not critical, just more frequent regen running low rpm.

Yours may have regened more and you didn’t know it. If it wasn’t for the smell, I would have never noticed mine doing it. The dash light is easy to miss in overhead sun.

Mine has developed the annoying habit of wanting to start on the way to get fuel. Driving 1/2 mile down the road to gas station it starts....meaning I have to wait or turn around and kill some time. I know I can put it off or shut down in process, but I don’t want to tempt fate so just let it do it’s thing

 

[CMV]

BTW.....good thread. I’m happy to see no mention of a heavier DPF being a critical deciding factor on purchase of machine ��

Just kidding. But I am looking forward to learning a little more about them. What I’m real curious about is “how long do they last?” Does the DPF that came on it last lifetime or after X hrs or Y regen cycles it has to be replaced. And if it does have a limited lifespan, does it have to be replaced or can you just drill it out like you could (illegally but would function) a catalytic converter on a car?

 

[pmsmechanic]

I had an interesting conversation with a mechanic friend of mine. He works for a dealership and told me that about half of the warranty calls they get are for emissions systems. Here is a example of the stupidity of it all. If the computer senses that the DEF heater isn't working properly it will turn down the horsepower of the tractor. Even in summer when a DEF heater isn't needed. It would only be a few lines of code to tell the computer to ignore the DEF heater malfunction in summer but that would be too simple so a farmer has to wait until the service mechanic can come out to fix the problem. This doesn't go over good with customers who can't get their crop off because someone was too lazy to write a few lines of code. My friend tells me that any used tractors that get sold have the emissions software deleted.

 

[Bigpuddie]

BTW.....good thread. I’m happy to see no mention of a heavier DPF being a critical deciding factor on purchase of machine

Just kidding. But I am looking forward to learning a little more about them. What I’m real curious about is “how long do they last?” Does the DPF that came on it last lifetime or after X hrs or Y regen cycles it has to be replaced. And if it does have a limited lifespan, does it have to be replaced or can you just drill it out like you could (illegally but would function) a catalytic converter on a car?

As a rule, The DPF is good for about 200 regens or 3000 hours

 

[jeff9366]

I had an interesting conversation with a mechanic friend of mine. He works for a dealership and told me that about half of the warranty calls they get are for emissions systems. Here is a example of the stupidity of it all. If the computer senses that the DEF heater isn't working properly it will turn down the horsepower of the tractor. Even in summer when a DEF heater isn't needed. It would only be a few lines of code to tell the computer to ignore the DEF heater malfunction in summer but that would be too simple so a farmer has to wait until the service mechanic can come out to fix the problem. This doesn't go over good with customers who can't get their crop off because someone was too lazy to write a few lines of code. My friend tells me that any used tractors that get sold have the emissions software deleted.

Just to be clear, neither subcompact nor compact tractors have DEF/urea.

I would prefer to focus this thread on Diesel Particulate Filters and compact class tractors for simplicity and clarity. Few tractor neophytes will purchase a utility class tractor as their first tractor.

Diesel Exhaust Fluid (DEF) as an auxiliary to DPF begins on Utility class tractors, the next heavier category of tractor.

I have no experience with DEF.





"Diesel Exhaust Fluid (DEF) is a non-hazardous solution, which is 32.5% urea and 67.5% de-ionized water. DEF is sprayed into the exhaust stream of some diesel vehicles to break down dangerous NOx emissions into harmless nitrogen and water. ... DEF is not a fuel additive and never comes into contact with diesel."

"A 32.5% solution of DEF will begin to crystallize and freeze at 12 deg F (-11 deg C). At 32.5%, both the urea and water will freeze at the same rate, ensuring that as it thaws, the fluid does not become diluted, or over concentrated. The freezing and unthawing of DEF will not cause degradation of the product."

 

[jeff9366]

As a rule, The DPF is good for about 200 regens or 3,000 hours.

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

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


I speculate that DPFs in warm climate areas like Florida, may last longer than DPFs used in cold climate areas where tractors in winter may warm at idle for thirty minutes prior to use, and tractors are used for snow removal in very cold temperatures. The DPF will be colder between winter regenerations in the northern tier of states.

I have yet to read anything here regarding my speculation. I do know my three cylinder Kubota L3560 runs sixty engine hours between regenerations.

 

[denchen]

This might sound a bit dumb, but most agree that breathing in diesel fumes, weather they have been through a DPF or other process, is not best for our lungs. But many tractors have their exhaust pipe right in front of the driver. This means that whilst travelling into the wind the driver is breathing in the exhaust fumes. Many have cabs, OK but still the cab is in the `fume cloud`. This leads to a question of, `would it not be better to move the exhaust pipe to somewhere else.` and `does the pipe have to be where it is or is just traditional, because that's where our fore fathers put them`

 

[jeff9366]

In the USA new compact tractors usually have exhaust routed under the tractor. My Kubota L3560 exhausts under the tractor to the front.

New Kubota utility tractors in USA have vertical exhausts. Hot exhaust wants to rise. Vertical exhaust may disburse processed exhaust before it contaminates organically raised crops during harvest. (??)

(During my working years I was tangentially involved with the production of certified organic wine grapes.)

My DPF equipped Kubota does not produce the diesel smell nor diesel smoke of pre-Tier 4/final emission technology tractors. The DPF is there to reduce particulate emissions. Today's diesel fuel in most, not all, of the world is ultra-low-sulphur fuel.

 

[RjCorazza]

...
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.
...

My L4060 has averaged 57 hours per regen across 5 so far.
Not that it really matters, but doesn’t the regen process use additional fuel by injecting it directly into the dpf ? I thought that was the case, but I checked the manual, and there is no mention of it.

 

[jeff9366]

When my Kubota L3560 regenerates during operation it is when I have planned mowing or Disc Harrow work in anticipation. When mowing or discing my tractor operates at nearly full throttle and the engine and DPF are hot. In this scenario I doubt any supplemental diesel fuel is used to increase DPF temperature.

In woods work, the largest segment of my tractor work, the engine seldom operates at a wide throttle setting for more than three or four minutes at a time, which would be towing a Oak trunk free from clinging vines and underbrush in HST+ LOW/LOW and 4-WD, using the rear/center drawbar.

In driveway regeneration it takes 3 - 4 minutes with the throttle manually set at 2,200 rpm before the engine and DPF are hot enough to activate regeneration cycle, which shows with a readout on the L3560 Intelipanel. Once regeneration commences, the tractor takes control of the throttle. My interpretation is the additional fuel is used to increase the tractor rpm to 2,200 while parked. I may be wrong.

The gauge monitoring engine temperature does not move up during regeneration, dynamic nor static. This puzzles me. Perhaps this is due to the large volume of fluids in diesel tractors and transmissions acting as a heat sink, while the DPF replaces an engine muffler and is directly connected to the engine exhaust manifold. (??)

Regeneration may use fuel directly injected into the DPF in colder climates. I do not know.

 

[CMV]

As a rule, The DPF is good for about 200 regens or 3000 hours

200 regens or 3000 hrs.....3000 hrs would always hit first unless something did a regen every ~15 hrs? I put about 120 hrs/yr on mine so that's roughly 25 yrs - regen about 40 hrs, 3000 hrs expected life. Doesn't seem too awful looking at it that way.

I do wonder what would happen if the DPF was just replaced with a straight pipe. Not that I have any intention of doing so, just curious.

As to the exhaust location....mine is front lower left. Tractor speeds are generally so slow that direction of travel vs placement isn't so much the issue as wind speed and direction. To the rear would be nice, but then all those hot gases on an implement or muffler/pipes mounted too low under machine getting damaged. Seems the traditional straight up from the hood or front/side are best overall locations. Everything is a compromise...... Mine is generally far enough away I rarely notice it. My old JD BH was center of hood and I'd get stinging eyes from it at times. Bigger older tech engine so a lot more exhaust, but I don't ever get that with this placement. I get that burning paint smell from regen cycles that I notice, but in general seldom notice exhaust.

 

[jeff9366]

200 regens or 3000 hrs.....3000 hrs would always hit first unless something did a regen every ~15 hrs? I put about 120 hrs/yr on mine so that's roughly 25 yrs - regen about 40 hrs, 3000 hrs expected life. Doesn't seem too awful looking at it that way.

For most, replacing worn tractor tires will be a greater expense than DPF replacement.

 

[CMV]

For most, replacing worn tractor tires will be a greater expense than DPF replacement.

What? I have to replace the tires too?



Sadly, I'll have to replace my rears probably WAY sooner than normal. When I first got it....maybe 10 hrs on machine....was ripping some virgin ground with box blade teeth fully lowered. That's how I found out my hydraulic toplink leaks down really fast. Box blade was up, toplink fully retracted, didn't think much of it. 30 min later realize the teeth are now in contact with tire lugs. Chewed out some real big chunks of the industrial treads. Just a matter of time until a screw, pointy rock, shoot, something finds one of those spots and pokes a hole.