MessickFarmEqu
Super Member
Some, including John Deere, are using EGR(exhaust gas recirculation) to meet the Tier 4 requirements.
The ERG systems need to power down the tractor for 5-15 minutes and burn off the deposits in the exaust filters every 5-12 hours (by burning diesel fuel). Literally... in the middle of the field... your tractor will power down and you have to sit and wait for the process to finish. No one seems to quite understand why Deere thinks this is a good idea. They'll probably only use this for a few years as it won't meet Tier4b. No one else is choosing an EGR system.
There seems to be some good advantages to SCR, mostly the fact that companies can finally tune their engines for performance rather than having to detune to meet emmissions as has been done with Tier2/3.