Tier 4

[Snowback]

Here is an interesting video that explains all Tier 4 and DOC. For the DOC portion go to 6:09.

https://www.youtube.com/watch?v=w_WWg7HpZ3c

Thanks Auburn Alum for staying objective and seeking facts. That was a great video and description of the Common Rail High Presure systems with a Catalytic Converter as opposed to a filter. Looks like there are more and more brands that are spending the time and money to roll out the DOC technology. Some brands currently use them in line with DPFs for even better emissions control in the event they have not gone to the high pressure common rail electronically controlled injection systems. (If utilized inline, DOC heat allows for continous passive DPF regeneration and less need to clean/regen DP filters)

As to some other information being posted on here, I believe it may be a bit disingenious to post misleading information about competitors' technologies. Diesel Oxidation Catalysts are really no more a "filter" than are baffled mufflers. Exhaust gasses pass through DOCs and a catalytic reaction helps burn off a few more contaminants before getting to the tail pipe. There is no trapping mechanism involved. Alternatively, DPFs physically trap the contaminants with membranes or other physical media that allow gas to flow, but the particles to hang up, and then they burn them off from time to time with some miniscule residue remaining, but essentially full flow capacity restored. Nothing wrong with that, but please don't take away from the other companies who have already taken the next step and rolled their existing technologies into the whole product line - including the lowly CUT that a guy like me can afford. High pressure electronic common rail injection along with exhaust gas recirculation is so efficient and burns so cleanly that only a DOC is required to pass Tier 4 for those companies.

Perhaps we can just acknowledge that for weekend warriors like me, low to no maintenance might be a good option. For now I'll stick with my machine that filters air coming into the engine, but not out of it.

Stay safe, and apologies if anyone is offended. I'm just a cold, calculating engineer who likes to make sure all of the facts are on the table. I'm happy to learn more and be corrected if I am mistaken.

 

[MessickFarmEqu]

Stay safe, and apologies if anyone is offended. I'm just a cold, calculating engineer who likes to make sure all of the facts are on the table. I'm happy to learn more and be corrected if I am mistaken.

Hey same here, If I'm wrong I'm happy to know. So in your application how is the engine preventing soot? There also has to be a mesh membrane in there for the diesel fuel injected into the exhaust stream to burn off on.

I think a lot of confusion on these things comes from the huge variety of systems out there. There are also some DOC systems in use that don't meet Tier 4 final but would have met intern that can't continue to be produced. I believe in those cases PM was the issue.

I genuinely enjoy this stuff, not trying to throw stones at all.

 

[AxleHub]

Duplicate

 

[AxleHub]

Hey same here, If I'm wrong I'm happy to know. So in your application how is the engine preventing soot? There also has to be a mesh membrane in there for the diesel fuel injected into the exhaust stream to burn off on.

I think a lot of confusion on these things comes from the huge variety of systems out there. There are also some DOC systems in use that don't meet Tier 4 final but would have met intern that can't continue to be produced. I believe in those cases PM was the issue.

I genuinely enjoy this stuff, not trying to throw stones at all.

While I don't own a brand you sell . . I always look forward to your posts.

I think its interesting that Kubota builds diesels with dpf or doc but chooses on their own to not use doc methods in their tractor products.

I don't believe readers see you as a stone thrower

 

[Snowback]

Hey same here, If I'm wrong I'm happy to know. So in your application how is the engine preventing soot? There also has to be a mesh membrane in there for the diesel fuel injected into the exhaust stream to burn off on.

I think a lot of confusion on these things comes from the huge variety of systems out there. There are also some DOC systems in use that don't meet Tier 4 final but would have met intern that can't continue to be produced. I believe in those cases PM was the issue.

I genuinely enjoy this stuff, not trying to throw stones at all.

Thanks for keeping an open mind MessickFarmEqu. We are all better when learning from one another and that is why I love this site. Lord knows I have the most to learn of anyone here! I too value your videos and input and wish more dealers would get involved with the community. (Dave's Tractor comes to mind as well.)

To answer your question above, I would encourage anyone interested in how the Mahindra mCRD system works to look at this link Introducing our Tier IV "mCRD Technology" | Mahindra, and also to also check out this independent interview and explanation here: Mahindra mCRD Diesel Technology There's no right or wrong way to implement Tier 4, but this mCRD was the best way for me. It is Final Tier 4 compliant and is in my opinion a great solution for at least the casual user, and perhaps even hard core farmers tilling, planting, and harvesting fields all day. There are no membranes or filters like in a DPF, only a flow through catalytic converter that is set up to allow for final exhaust gas conversion of noxious gasses as the exhaust stream passes over and through the catalyst coated surfaces in the DOC pod. Since the efficiency of the engine itself is better there is far less "soot" to begin with than a lower pressure system would generate. Now if a guy dropped a shovel full of mud into the exhaust manifold, then there is a possibility that both systems could get plugged I suppose...

From the Tractor.com site - (Bold Italic words are my highlights)
---------------------------
"Mahindra's approach to EPA FT4 requirements (mCRD) began with what would turn out to be a $30 million investment. Involved were major design modifications to the crankcase, crankshaft, connecting rod, piston, flywheel, gear train, cylinder head, and manifolds. A Bosch Common Rail Diesel (CRD) system delivering fuel at 23,000 psi is at the heart of controlling Mahindra engine emissions and greatly reduces engine smoke while delivering the added advantage of decreased sound levels. The mCRD system allows for more efficient fuel combustion through multiple injections per cylinder stroke. For engines above 50 horsepower, a waste gate turbocharger is used along with an air-to-air intercooler.

In conjunction with the CRD performance advantages, Mahindra uses an EGR system with a higher rate of recirculation, a DOC and CCV. mCRD ends up being a simpler solution, with only a $600 tool and any laptop being required by dealers to diagnose the system verses the reports we had heard from competing manufacturer dealers of requiring investments of up to $8000 plus additional technician training. And forgoing the DPF route means no excess heat from the DPF blowoff, lesser system complexity, no potential for the DPF to plug up or need replacement, and no requirement for a back pressure sensor."
----------------------------------
Lastly - I love all brands and know that there are pros and cons to each. I wish folks would simply acknowledge and reward companies that try to meet specific groups of customers' needs. Mahindra, Shibarau, John Deere, and many bigger name brands have put out High Pressure Common Rail DOC systems that negate the need for a DPF and the associated regen challenges. Even Kubota has recognized the demand for a simple and easy use system and has put out its own DOC only emissions control engines on some of their larger models last year. Kubota Expands Diesel Engine Line-Up by Adding New Diesel Oxidation Catalyst (DOC) Only Option (19-56kW) | News 2014 | Kubota Global Site Perhaps it was not across the board due to the cost of retooling the engine designs and plants. If their customers don't complain and only buy Orange K-Tractors each and every time then they are completely justified in making that additional profit margin. Good on them for looking out for their internal stake holders. Mahindra is a new kid on the block and decided to offer something more attractive. I bit off on it, so they must be doing something right. Competition and innovation can only help all of our favorite brands do better in the future in my humble opinion. As a dealer I would be all over my distributor and corporate HQ demanding that the products I sold for them were the best of the best with features that compare or beat the brands I did not deal. Would make my sales easier as well.

As alluded to earlier in this thread by a wise man, all of this Tier 4 discussion may be moot soon if/when Tier 5 comes into being. In that case the DPFs or possibly some DEF injection may be required on all brands just to meet those criteria. This linked article discusses the electric hybrid possibility as well. Beyond Tier 4 Engine... | New Tractors | Agriculture

Take care everyone!

 

[AuburnAlum]

Still on my journey for a tractor. I visited my Massey Ferguson dealer and was curious what was on the engine tag on the 2705/6e. Interesting there is a line on the stage stating "Carb replacement: 7 years or 5000 hours" This is for the DOC engine without DPF of course. So it does have to be replaced like the DPF.

 

[K Arno]

What does CARB mean there? Is it California Air Resource Board? I know where I live we use that standard on vehicles. Is that the length of time the system is valid? I don't know, but would like to.

 

[AuburnAlum]

What does CARB mean there? Is it California Air Resource Board? I know where I live we use that standard on vehicles. Is that the length of time the system is valid? I don't know, but would like to.

I would assume that it is refers to 'carburetor'. Not sure that California Air Resource Board would make sense across the US. But I could be wrong.

 

[aczlan]

I would assume that it is refers to 'carburetor'. Not sure that California Air Resource Board would make sense across the US. But I could be wrong.

Many states follow CARB emissions rules, so its possible that it is across the US.

Aaron Z

 

[AuburnAlum]

Many states follow CARB emissions rules, so its possible that it is across the US.

Aaron Z

So what is replaced at 7 years or 5000 hours that it would be referencing?

 

[Snowback]

Still on my journey for a tractor. I visited my Massey Ferguson dealer and was curious what was on the engine tag on the 2705/6e. Interesting there is a line on the stage stating "Carb replacement: 7 years or 5000 hours" This is for the DOC engine without DPF of course. So it does have to be replaced like the DPF.

View attachment 454220

Great continued research AuburnAlum. Lots of good info being shared here. In response to your observation, I believe there should not be a practical need to ever replace a DOC if you choose to go that route. Also - in reality most folks with DPF systems will not be replacing those either unless they use the heck out of them. It might hurt the DPF engine resale value though if getting on up in hours in my opinion.

That engine emission info label notes all of the equipment Shibaura uses in its Tier 4 complaint system. (PCV, EGR, DOC, ECM, etc...). It states that it is EPA and CARB compliant. The next line under the listing of control mechanisms states how long that Shibaura and CARB, (California Air Resource Board), believe that system will effectively control the emissions to within the specifications required for Tier 4. (Its useful life). In the case of this type of engine, it is possible that the catalytic converter itself may not be converting all of the noxious gasses 100% into water and other non offensive compounds and elements after 7 years of use, or 5000 hours. However, barring abuse through dumping solids into the exhaust manifold, (sediment from deep water submersion, running in dirt with no air filter, etc...), the device itself should not be compromised, and exhaust gasses should still be flowing freely through the DOC, (Cat - in old man car terms), and it will simply be less effective at converting the gasses as time passes on. I do not believe there would be any performance drop.

In my opinion the only time you would have to replace a DOC is if you wanted to re-certify it as CARB compliant 15 years from now after using hard every day. Recall that a DOC has no filter or membrane, just a large surface area of plates that are coated with a catalyst. This helps convert the noxious gasses into harmless materials as the gas passes through the DOC. The effectiveness of the catalyst may wane somewhat over the decades, but unless your entire exhaust system rusted out, I honestly feel a DOC will be hard to compromise. Please verify or correct what I am saying if even better info is available. Perhaps your dealer could give you the hotline to Massey's corporate customer service team so you can confirm what you are finding in your search, or hearing from us. I'll admit they will know much more than me, and should be a good source if they are honest with you. I was able to get all of my in depth technical questions answered though a Product Development Manager at Mahindra when I was in your shoes and trying to address similar questions. Can't hurt to ask him... Good luck!

 

[K Arno]

I would assume that it is refers to 'carburetor'. Not sure that California Air Resource Board would make sense across the US. But I could be wrong.

A diesel doesn't use a carburetor. They throttle by varying the amount of fuel injected. To prevent the Balkanization of emissions standards any state that wants to go further than Federal standards uses the California regs. Having the paint on my car ruined living near a runway with Bucky balls falling from the sky unburned fuel can make lots of "stuff" you don't want in your lungs. https://en.wikipedia.org/wiki/Buckminsterfullerene

 

[GManBart]

I would assume that it is refers to 'carburetor'. Not sure that California Air Resource Board would make sense across the US. But I could be wrong.

Not many carburetors on diesel engines

What that most likely means is that for it to be compliant with CARB (California Air Resource Board) standards it needs to be replaced at 7 years or 5,000 hours. It doesn't mean it won't still be working, or really need to be replaced, just that CARB has established what may be an arbitrary replacement timeframe for them.

 

[buickanddeere]

I thought I seen somebody here all proud of thier under 50HP being clean with minimal complexity and expense . Well it just maybe because the there are two sets of less stringent emission specs for under 50HP.
eCFR ? Code of Federal Regulations

 

[buickanddeere]

I thought I seen somebody here all proud of thier under 50HP being clean with minimal complexity and expense . Well it just maybe because the there are two sets of less stringent emission specs for under 50HP.
eCFR ? Code of Federal Regulations

 

[Helitech]

That someone is probably me. DOC equipped Branson with mechanical injection. Stand alone monitoring of the DOC. 55 horsepower 5520R.

 

[AuburnAlum]

Not many carburetors on diesel engines

What that most likely means is that for it to be compliant with CARB (California Air Resource Board) standards it needs to be replaced at 7 years or 5,000 hours. It doesn't mean it won't still be working, or really need to be replaced, just that CARB has established what may be an arbitrary replacement timeframe for them.

LOL. early morning posting. Was thinking catalytic converter and carburetor typed out. ;-)

 

[AuburnAlum]

Great continued research AuburnAlum. Lots of good info being shared here. In response to your observation, I believe there should not be a practical need to ever replace a DOC if you choose to go that route. Also - in reality most folks with DPF systems will not be replacing those either unless they use the heck out of them. It might hurt the DPF engine resale value though if getting on up in hours in my opinion.

That engine emission info label notes all of the equipment Shibaura uses in its Tier 4 complaint system. (PCV, EGR, DOC, ECM, etc...). It states that it is EPA and CARB compliant. The next line under the listing of control mechanisms states how long that Shibaura and CARB, (California Air Resource Board), believe that system will effectively control the emissions to within the specifications required for Tier 4. (Its useful life). In the case of this type of engine, it is possible that the catalytic converter itself may not be converting all of the noxious gasses 100% into water and other non offensive compounds and elements after 7 years of use, or 5000 hours. However, barring abuse through dumping solids into the exhaust manifold, (sediment from deep water submersion, running in dirt with no air filter, etc...), the device itself should not be compromised, and exhaust gasses should still be flowing freely through the DOC, (Cat - in old man car terms), and it will simply be less effective at converting the gasses as time passes on. I do not believe there would be any performance drop.

In my opinion the only time you would have to replace a DOC is if you wanted to re-certify it as CARB compliant 15 years from now after using hard every day. Recall that a DOC has no filter or membrane, just a large surface area of plates that are coated with a catalyst. This helps convert the noxious gasses into harmless materials as the gas passes through the DOC. The effectiveness of the catalyst may wane somewhat over the decades, but unless your entire exhaust system rusted out, I honestly feel a DOC will be hard to compromise. Please verify or correct what I am saying if even better info is available. Perhaps your dealer could give you the hotline to Massey's corporate customer service team so you can confirm what you are finding in your search, or hearing from us. I'll admit they will know much more than me, and should be a good source if they are honest with you. I was able to get all of my in depth technical questions answered though a Product Development Manager at Mahindra when I was in your shoes and trying to address similar questions. Can't hurt to ask him... Good luck!

Thank you for the compliment. :thumbsup: After all this research and the help of this forum I'm pretty confident I have nothing immediately to worry about if I choose DPF or DOC.

 

[Threepoint]

lights will flash on the dash once the DPF restricts telling them to do it, if they ignore that and keep running eventually they will end up in "limp" mode...[snip]

Neil, thanks for your good input in this thread. Basic question: When a Tier 4 DPF Kubota goes into "limp" or "limp home" mode, how does it actually behave? Restricted rpm and low power? Something else? I'm assuming my 2014 Kioti NX would be the same, as it too has a limp home mode, although I've never experienced it.