As a way to meet current Stage IIIB emission regs, all the big tractor makers use SCR (selective catalytic reduction) and AdBlue liquid. All, that is, except John Deere. How does the Deere way stack up? profi had the DLG test station run a tractor in the field and lab to find some answers.
Two years ago, Deere’s European President claimed that the Stage IIIB emission targets could be met using EGR (exhaust gas recirculation) and a diesel particulate filter. And he has been proved right: today, the company’s 6R, 7R, 8R and 9R range engines all comply with current Stage IIIB emission requirements through their mix of cooled EGR, diesel oxidation catalyst (DOC) and diesel particulate filter (DPF). Game over, then. Not necessarily. Other makers argue that the alternative SRC/AdBlue route frees an engine to be run more efficiently — improving fuel consumption and power output — while the dirtier exhaust gas it produces can be cleaned up outside the cylinders. Deere (plus Cat and Volvo in the construction industry) just smiles and points to the lack of an AdBlue tank, its associated controls and complicated plumbing on its machine lineup. The other camp then counters with the fact that diesel has to be burned to regenerate (clean up) an EGR system’s particulate filter. And so on the corporate philosophy ping-pong continues.
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