Doesn’t make sense. John Deere still using dpf in their motors under 100hp. Reason why I won’t trade my 2011 tractor in that doesn’t have emissions. Seems like mahindra only one using the technology where there is no future headaches and have been using it for years to meet the tier
Its all about the burn. Control the burn, keep the combustion temp down. Inject the proper amount of fuel at the right time, get a complete burn, no soot/particulates. Small engines designed to run at mostly fixed RPM’s could probably go with out a DPF, but still would need SCR for NOx reduction.
If you look at farm tractor specs, seems like every engine above 25HP requires dpf system. When Obama was still president, he had the EPA come down on glider kit manufacturing. Fitzgerald for example would have been completely shut down, they fought it, but were only allowed to produce 300 units vs the 3000 a year they were doing. I haven’t read up on the current state of affairs. The argument Fitzgerald made was the epa was using outdated emissions data and applying it generically across the remanufactured engines, but Fitzgerald uses non factory spec components in the valve train and other parts.
Federal gooberment got together with carb and decided that scr and dpf are no longer needed because cpap has been found to control emissions much better.