mCRD

[Peter 315]

False, that's not how it works. Actually the opposite compared to DPF.

Well , That' what I read somewhere , So I was wrong Do you think that the filter on the Mahindra is not going to plug up after time ?

 

[RNeumann]

The Mahindra uses a catalytic converter. It’s not a known wear item- no catalytic converter is. In fleet service “known wear items” are given a replacement or inspection interval.

With regards to heat. The hotter (in general) the engineers can make a motor the cleaner it burns. As technically has improved and emission requirements have increased engine temps have risen. It’s been across the board- cars, trucks and tractors etc.

The regen adds enough heat to the DPF (as it burns off particulates) and exhaust that we’ve had it melt a spot on the asphalt in our back lot. Different manufacturers have dealt with this differently- heat shields, redirect exhaust etc. Kubota added vents to the hood to help get rid of the heat buildup.
This isn’t a knock on one vs the other. It’s just the reality of modern emissions. We are fortunate to have a choice between several different approaches with regards to tractors.

 

[Peter 315]

I know car catalytic converters are different but I know that they will plug up. I wonder if that system on the tractor will too ?

 

[s219]

Interesting replies- both Kubota owners.....

What has that got to do with anything? What is the purpose of your comment other than to turn this into a brand bashing thread?

The whole point of my post is that both systems are heavily reliant on computer control and sensors, and those are the weak spots. And I'll be fair to note that both Kubota and Mahindra have had issues with emissions software and control on their tractors. Anybody, including a salesman, who thinks it's super important whether a tractor uses a DPF or a DOC or whatever, is missing the point that the computer, the software, and the sensors are the complicated parts. What's inside a chamber on the exhaust plumbing is a minor factor. It's not that simple. If you want simple, get a Tier 4 Interim tractor without the computer or sensors.

 

[MatHaas]

I know car catalytic converters are different but I know that they will plug up. I wonder if that system on the tractor will too ?

I can't say I agree with you. With a proper running engine, the DOC should last a long time. I've never replaced a catalytic converter on any of my vehicles. I've owned about 15 different vehicles, ranging from production years 1980 to 2007, including vehicles i've put 200k+ miles on them personally. When a cat clogs up, it's likely from other engine issues allow excess contaminants in the exhaust; IE inefficient combustion, excessive blow by, burning oil, etc.

That's the point of the modern electronic engine management. Optimize the engine to fully burn the fuel put in the combustion chamber. Then additional circuits that recirculate exhaust gas to burn any other unburned fuel particles. resulting in a much "cleaner" final exhaust gas. which then runs over a simple catalyst material to further oxidize the gas.

 

[Peter 315]

I can't say I agree with you. With a proper running engine, the DOC should last a long time. I've never replaced a catalytic converter on any of my vehicles. I've owned about 15 different vehicles, ranging from production years 1980 to 2007. When a cat clogs up, it's likely from other engine issues allow excess contaminants in the exhaust; IE inefficient combustion.

That's the point of the modern electronic engine management. Optimize the engine to fully burn the fuel put in the combustion chamber. Then additional circuits that recirculate exhaust gas to burn any other unburned fuel particles. resulting in a much "cleaner" final exhaust gas. which then runs over a simple catalyst material to further oxidize the gas.

If it works the way it should ,But no matter what we are all screwed anyways

 

[MatHaas]

With regards to heat. The hotter (in general) the engineers can make a motor the cleaner it burns. As technically has improved and emission requirements have increased engine temps have risen. Itç—´ been across the board- cars, trucks and tractors etc.

I don't think it's generally the hotter the cleaner. It's that we've found the most efficient equation to (optimal temperature and amount of fuel) to get the most efficient combustion. there are plenty of materials that would hold up to an operating temperature of 300 degrees, but that's wouldn't make the combustion better, nor would it be "cleaner". yes, excessive heat will incinerate waste products in the exhaust, but that's where the DPF/regen/DEF come in; but we're talking about operating temperatures, and you can have operating temperatures through the roof and have poor combustion and excessive waste in exhaust. that's the number one reason you need to be careful on diesels; because more fuel adds more power, but it also adds more heat. you start dumping tons of fuel, pouring black smoke out the exhaust, making more power, and your EGTs go through the roof, some to the point of melting the exhaust valves, but your exhaust is FAR from cleaner.

not that you were exactly saying that, but it should be clarified. the only reason engines run "hotter", is because we found out that we weren't in optimum operating temperatures to have the most efficient fuel combustion. gas engines have had operating temps of 190-210 (+/- 10 or so degrees) for over 60 years, back when basic carbs were the cream of the crop. pretty sure diesels haven't varied substantially either over a similar time frame, just the gradual increase. limitations in efficient cooling systems were also likely a factor.

the physical properties of engine materials used, oil properties, etc all have a play an additional role on ideal temperature as well; but i think the main focus has been around the most efficient combustion.

 

[Bud Soda]

Well , That' what I read somewhere , So I was wrong Do you think that the filter on the Mahindra is not going to plug up after time ?

If you don't like the DPF take it off. I took mine off at 12 hours, about 200 hours now and never needed a regen.

 

[MatHaas]

What has that got to do with anything? What is the purpose of your comment other than to turn this into a brand bashing thread?

The whole point of my post is that both systems are heavily reliant on computer control and sensors, and those are the weak spots. And I'll be fair to note that both Kubota and Mahindra have had issues with emissions software and control on their tractors. Anybody, including a salesman, who thinks it's super important whether a tractor uses a DPF or a DOC or whatever, is missing the point that the computer, the software, and the sensors are the complicated parts. What's inside a chamber on the exhaust plumbing is a minor factor. It's not that simple. If you want simple, get a Tier 4 Interim tractor without the computer or sensors.

good point.

I think it's a bit early to tell, but the ultimate decision would be if you could calculate which lasts longer in the long run.
The computer software, electronic components, etc are all still a newer application. As well as the exhaust treatment systems.

In my opinion, i'd rather treat the root of the problem. And that's the engine, it's fuel management, and combustion efficiency.
I don't own a DPF/DEF vehicle, nor do i know the ACTUAL service life of them or cost.
I am familiar with electronic engine managment, and with the right components, they can be very reliable. We're still working on reliability & optimization though for these tractors though.

In my eyes, it's just like the transition from carbs to fuel injection. and i think fuel injection was a huge success. sure there's more parts, but once it's all figured out and the quality is there too, it's well worth it. but that is just my opinion.

 

[sd455dan]

I don't think it's generally the hotter the cleaner. It's that we've found the most efficient equation to (optimal temperature and amount of fuel) to get the most efficient combustion. there are plenty of materials that would hold up to an operating temperature of 300 degrees, but that's wouldn't make the combustion better, nor would it be "cleaner". yes, excessive heat will incinerate waste products in the exhaust, but that's where the DPF/regen/DEF come in; but we're talking about operating temperatures, and you can have operating temperatures through the roof and have poor combustion and excessive waste in exhaust. that's the number one reason you need to be careful on diesels; because more fuel adds more power, but it also adds more heat. you start dumping tons of fuel, pouring black smoke out the exhaust, making more power, and your EGTs go through the roof, some to the point of melting the exhaust valves, but your exhaust is FAR from cleaner.

not that you were exactly saying that, but it should be clarified. the only reason engines run "hotter", is because we found out that we weren't in optimum operating temperatures to have the most efficient fuel combustion. gas engines have had operating temps of 190-210 (+/- 10 or so degrees) for over 60 years, back when basic carbs were the cream of the crop. pretty sure diesels haven't varied substantially either over a similar time frame, just the gradual increase. limitations in efficient cooling systems were also likely a factor.

the physical properties of engine materials used, oil properties, etc all have a play an additional role on ideal temperature as well; but i think the main focus has been around the most efficient combustion.

Agree,
I think it is more about the actual injection pressure and timing control.
mechanical injection is generally between 2500-5000 psi .
When you get into common rail injection with CPU controlled electric injectors pressures jump up dramatically to well over 20,000 psi and with the Bosch CP4 systems now on some engines are over 36,000 psi These higher pressures allow for a much finer spray from the injector which is easier to ignite add in the ability to add multiple injection events and complete control of the timing it makes sense that fuel use and emissions can be reduced.