Thanks for your input MHarryE. Empirical data is the best data. We just need lots of it!
How certain are you of your facts regarding the extreme temperature needed for a DPF to regenerate?
Pressurized diesel burns at about 1,000+ degrees in the combustion chamber. When diesel is injected and burned in the DP filter it serves as a secondary combustion chamber, so I am quite certain of that high temperature of regen. Most dealers and internet resources will tell you between 900 and 1,150+/- deg F inside the DPF during regen. I have not seen it in person, but believe the experts.
My DPF equipped tractor has a DPF temperature that I watch out of curiosity. In much of my work, high PTO load or tillage, my exhaust temperature will be running over 1,000 degrees and the highest temperature I have seen at the end of a regen (that's when the temperature is highest) is 1122. Also I care an I-R thermometer with each of my large pieces of equipment with which I can check bearing temperatures on our balers, combine, etc., to detect an impending failure and avoid downtime during the day. I have checked my exhaust stack and don't not find it significantly hotter at regen than it is when normally working hard.
Well this is good info. For you it is hot either way, which makes sense when working hard. I am curious if the high heat is on your manifold/DPF, or at the exhaust tip? Most diesel trucks will drop a couple hundred degrees across the turbo, but during regen they still have exhaust pipe temps 100-300 degrees higher than equivalent engines that are not going through an additional combustion process downstream of the engine block. My earlier observation about the higher exhaust pipe exit temps were directly attributable to the Forestry Service study I linked, and those were diesel trucks, not tractors - so a study should be done on tractors as well. I acknowledge that.
Does Mahindra have a design advanced above everybody else?
Yes - It appears so as far as what is commercially available. Please see
Introducing our Tier IV "mCRD Technology" | Mahindra From a consumer and user standpoint, their design is simpler and easier to use in my humble opinion. I have a brand new 38 HP tractor and I do not have to think about DPFs or DPF regeneration. That is kind of nice, and and advantage to me, but maybe not to everyone.
Until engines started changing with emissions regulations, most were running with ancient, not very efficient technology. When Tier 3 came into being and John Deere tested their first Tier 3 tractors with their first use of cooled can EGR, they blew away all past economy records with their 8000 series tractors. The technology has been there but nobody wanted to be first as there were bound to be teething pains and technology drives initial cost.
Exactly - Mahindra stepped out and spent the money to make this happen without the need for a DPF. I hope there are no unforeseen teething pains that have not already been addressed...
We at Caterpillar advertise our small wheel loaders as being 30% more fuel efficient than their predecessors. Of course that isn't the big advertising coup it would have been back in 2008 when diesel was $4.50 per gallon but back then who predicted there would be the oil glut we have today?
Improved efficiency is great and we need to continue to improve. Kudos to you all at Caterpillar for the great work. I'm enjoying cheap gasoline and diesel right now like everyone else, but this likely won't last forever. The world consumes north of 93 Million barrels of liquid hydrocarbon every day. Most of that is crude oil with some NGLs and condensate thrown in. Sure we are producing just a bit more than that each day, but with the price of oil crashing there have been many rigs idled, and numerous mega projects put on hold. At a global consumption rate of almost 3 Billion barrels of oil per month, plus the laws of physics keeping a base production decline rate of 4% + in play, it won't take long to get the market balanced again. Fill up your tanks while you can!