DPF life is subjective....
Depends on a LOT of things. Fuel quality. How the engine and or tractor is used. Idle time. Lugging (lots of load and low RPM). etc etc.
Think about the old non DPF tractors. Think about when they smoke. When you first start them. When you lug the engine under a load so that it's making exhaust smoke. The smoke is fine particles of soot that are considered normal for all diesel engines. The DPF catches that soot in a fine filter. Every so often, the filter gets real dirty and then the sensors in the system tell the ECU (and ultimately the operator) that it needs to convert that soot into ash.
Some operators lug the ever living crap out of their tractor, they start and stop the engine often, and never get them above 2000 RPM. I know one guy who does this and in 65 hours has been into 5 regen cycles. Obviously he hates the DPF system, but neither your or I or him have any control over what the government mandates to be put on our diesel fueled equipment.
DPF life. Equipment that is run hard and stays hot (above about 1200 degrees F EGT) will have a LOT longer DPF life than one that is lugged, started and stopped often, runs cat pee diesel fuel, dumps 10 kinds of additives into the fuel, old diesel, gasoline in the fuel, 2 cycle oil in the fuel, etc. A poorly maintained engine will begin to burn some oil, and that too plugs the DPF quicker than normal. We've been seeing this with some of the hobby farm customers who forget to check the air filter. Yes those air filters are expensive. But that engine (on an L01) is $10,000+ worse case scenario. Plus the cost of the DPF, and those aren't cheap either. I've had to replace two in 3 years, out of about a thousand tractors. That's pretty good but IMO, that's 2 too many. One was the result of a level 5 regen, it was so plugged that it simply could not burn off the soot, it just made lots of ash. The other a result of a tractor that was rolled over, the engine ran on it's own oil for a length of time, and then the DPF became damaged. DPF's are not 100% efficient, so that over time, the burnt ash will eventually build up to a point where it cannot burn off during a normal regen cycle. This can be seen with the Kubota software on a laptop. They call it PM (particulate matter), and it's shown in mg. When that happens, you either have to replace the DPF, or remove it and have it cleaned by a company who specializes in this. The local company who does this usually charges about $300 to clean them, but that is on big trucks (Cummins ISX, garbage trucks). I have not asked them about Kubota's yet.
What happens if the tractor is left alone, say a guy sees a light and a beeper show up on the dash and ignores it? Eventually it plugs to the point where the engine's exhaust gas temperature (EGT) is so high, due to exhaust being plugged up, that it will eat itself. Melt pistons. Now, Kubota has sensors in the DPF that sense the EGT, and it too can be read with diagmaster, and the ECU reads those and adjusts injection timing and injection pulsewidth-among other things-to compensate. But an operator who simply doesn't care or just ignores the lights in the dash, yes, it is possible for the engine to eat itself alive. I haven't seen it personally, have heard of it though on a bigger M series. That would be an expensive mistake to make. Same thing that big truck owners face. Actually if you have a 25+hp diesel engine on anything, from about 2014 and newer, it's an issue that we'll all face. Personally, my opinion on the matter is that gasoline is going to be a better fuel for smaller tractors, for this reason. The technology is there to make a little 3 cylinder engine with a turbocharger to make just as much-if not more-torque than a 3 cylinder diesel, and it'll be quieter, smoother, use roughly the same amount of fuel, and overall be cheaper to own over the lifetime of the unit. Exactly the same as all of the F250's, Silverado 2500's, and Ram 2500's (and now the 1/2 ton diesels) that people buy just because they're diesel. Many never see a load to pull. Once you figure in the extra cost to maintain them, and they systems that they have, plus now DEF every so often, you come out cheaper with gasoline in the long run.
I think it's time for Kubota to try out a gasoline powered tractor for this reason, something in the 30-35hp range outta do it. Some say it's a step back in time, and it is to an extent, but with the government mandates on diesel fueled engines, it makes sense. Especially for those "hobby farmers" who use a tractor for a toy as opposed to "real" work (plowing, planting, etc). And yes I fit into the hobby farmer category. I have a little 35hp tractor and really have minimal uses for it. Move some dirt once in a while, clean out the ditch, and use the FEL for lifting junk or loading with firewood to move from the back yard to the garage when that time comes. Nothing I couldn't do with a shovel and some walking but the tractor is just more fun.
) but if they will last 6,500 hours, even a $25,000 machine costs less than minimum wage per hour and does a whole lot of work.
