Compact Tractor Diesel Particulate Filters (DPF) Version 2.0

[jeff9366]

Beginning about thirty-three horsepower most tractors have Diesel Particulate Filters.
A few Tier IV compliant tractors between 26 and 75 hp use DOC (Diesel Oxidation Catalyst) conversion. Mahindra is one. Mahindra has DOC of similar construction to DPF. Both DPF and DOC are honeycomb ceramic filters which supercede a muffler.
The DOC forces engine exhaust over a honeycomb ceramic structure coated with platinum, palladium, and rhodium. These catalysts oxidize carbon monoxide and hydrocarbons into carbon dioxide and water at hot exhaust temperature.

Mahindra has a DOC oven hot all the time, DPF tractors have an oven hot intermittently. There is no free lunch.

Diesel DOC emits dirty exhaust until hot, which would not be allowed in USA road vehicles. Or possibly Mahindra evaluated the $30 billion (and counting) costs incurred by VW for falsifying diesel emission tests and decided its truck technology is not clean enough for export.

BY NOVA3930:

Trying to reconcile all this with what I know about diesel combustion and on road emissions from my various Cummins engines.

Tractor designs only utilizing a DPF, the engineers have probably decided to run relatively rich mixtures and/or are running LOTS of exhaust gas re-circulation (EGR). Those factors reduce combustion temperatures, reducing both NOX and CO at the expense of soot production, which they then clean up with the DPF.

A design utilizing a DOC without DPF is probably running a relatively lean mixture with less EGR, reducing soot and hydrocarbon emissions at the expense of CO and NOX, the CO being cleaned up by the DOC. In the case of the Mahindra with the common rail direct injection, they're probably using multiple injection events to control the combustion process and thus emissions. As I understand their system it's roughly equivalent to an on road truck of the early to mid 2000s vintange. The 03-07 5.9L cummins was a common rail direct injection system with EGR and DOC.

The thing I"m seeing that I guess allows for just using a DOC or DPF and not both is that Tier IV has a combined standard for NOX and hydrocarbons instead of being separate values as in on road requirements. It gives a lot more flexibility in meeting the standards.

I'd also hesitate in directly comparing a DOC with a DPF in their operation. A DOC operates effectively at 300*C+ when a typical diesel EGT is in the 700-800*C range, with bursts over 1000*C. A DOC will operate all day every day just by operating the engine, they don't require any extra fuel.

A DPF in comparison typically requires 900*C just to start consuming soot and requires much higher to consume soot faster than it's produced. That's why they have regen cycles at all. Diesel is injected late in the exhaust stroke where it combusts in the exhaust effectively, driving up the temp to burn the soot. Even then the things still plug up eventually.

Given my experience with on road engines, I'd take a common rail direct injection engine with a DOC over a DPF equipped vehicle all day every day. DPFs are the most problematic emissions component on modern on road diesels. On top of that I wouldn't want a DPF without SCR to allow combustion parameters that minimize soot production to start with.

That's just my general view of the various methods, I don't have any experience with the Mahindra system. All my experience comes from the on road world.

 

[RalphVa]

Gone are the days when as a Benz diesel owner, you could discourage a tailgater by flooring the accelerator. You didn't accelerate away from him as much as you hid him in a black cloud of diesel smoke and particulates.

Yeah, the air is cleaner.

Ralph

 

[nova3930]

Nevermind, think I was redundant

 

[buickanddeere]

Emission Standards: USA: Nonroad Diesel Engines

 

[jeff9366]

VIDEO: Worksaver Electric Grapple for your Tractor - YouTube

Interesting. Seems a bit slow for my liking. I believe that electrical linear actuators will become more prevalent in many applications going forward. To me, the ideal applications are for things such as snowblower chute left/right up/down functions where hydraulics are overkill to say the least.

Europe is legislating to prohibit sales of new fossil fueled tractors, vehicles and other equipment, led by Germany and Norway.

I speculate the first battery powered subcompact tractors will be on the market during 2026. Diesel subcompact tractors have lower power requirements, generally operate close to home so charge can be by electric car charging technology. Existing subcompact tractors have no emission controls, so spew a lot of pollutants for engine power output.

I speculate first stage will be subcompact tractors to 2,000 pounds bare weight, second stage compact tractors to 3,000 pounds bare weight, such as the sooty Kubota "loophole" L2501 and L2501 clones in other brands, with Tier V emission controls mandatory on tractors over 3,000 pounds bare weight.

Electric grapple is one mark of transition to electric power for light tractors.

 

[jeff9366]

rademamj1

The DPF % fill is calculated by the computer, based on in incoming exhaust pressure versus the outgoing exhaust pressure at the DPF. The differential pressure across the DPF measures the blockage on the ceramic filter screens, also called percentage of DPF fill.

 

[jeff9366]

Like the fuel economy of my diesel now.

I cannot comment specifically on your JD 4300 tractor but bear in mind the changes that Tier IV brought to diesel engines to make them burn 99% cleaner also made them more efficient and increased horsepower 2-horsepower to 4-horsepower over predecessor Tier II and Tier III engines. Even factoring in stationary regeneration, I expect most Tier IV compliant tractors have improved fuel economy over predecessor Tier II/III models.

The DPF only deals with the small fuel particulates still expelled by the 99% cleaner engines.

My Kubota regenerates routinely every 60 engine hours in warm Florida. 60 engine hours = 3,600 engine minutes.
Stationary regeneration, which is about 60% of my regenerations because I work in the woods, takes consistently 16 minutes in warm Florida.

16 / 3,600 = .0044 = .44% engine time used in stationary regeneration. (Less than 1/2 of 1%)

 

[jeff9366]

Tier 4 stuff scares me to death, i've never used a machine with it and i've read the stories, it seems some are great and some are just problems. I'm also looking at a massey 2604- apparently it uses a DOC instead of a DPF, apparently it doesn't regen. The farmers around here won't part with pre-emission control equipment.

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. Tier IV began phasing in during 2009, retail conversion was almost complete in 2013 when I bought my 'Tier IV' Kubota L3560.

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.

My Kubota regenerates routinely every 60 engine hours in warm Florida. 60 engine hours = 3,600 engine minutes.
Stationary regeneration, which is about 60% of my regenerations because I work in the woods, takes consistently 16 minutes in warm Florida.

16 / 3,600 = .0044 = .44% engine time used in stationary regeneration. (Less than 1/2 of 1%)


DPF is used by the majority of tractor manufactures on >25.4794-horsepower models, but not all.

A few Tier IV compliant tractors between 26 and 75 horsepower use DOC (Diesel Oxidation Catalyst) conversion. DOC is of similar construction to DPF. Both DPF and DOC are honeycomb ceramic filters which supersede the muffler. The DOC forces engine exhaust over a honeycomb ceramic structure coated with platinum, palladium, and rhodium. These catalysts oxidize carbon monoxide and hydrocarbons into carbon dioxide and water at hot exhaust temperature.

DOC equipped tractors have an oven hot all the time, DPF tractors have an oven hot intermittently.

DPF and DOC supersede the tractor muffler.
At some point in time tractors with mufflers need the muffler replaced.
At some point in time DPF needs to be replaced.
At some point in time DOC needs to be replaced.

There is no free lunch.


Tire wear and tire replacement will cause as many headaches and more expense than DPF/DOC for most long term compact tractor owners who read and comprehend their tractor's Operator's Manual.

 

[Milo]

I assume emission requirements will further tighten, does anyone know when tier V is coming and what it will entail?

 

[nova3930]

I assume emission requirements will further tighten, does anyone know when tier V is coming and what it will entail?

The general EPA push is to "near zero" emissions across the board so don't be surprised to see a tightening of both particulate, SOX and NOX standards. Give it another 10-15 years and I expect basically every diesel engine made will be fitted with DPF, DOC and SCR systems.