I suspect it was mainly the DPF that they were trying to ‘protect’ by having it run ‘part-time’. The thing would likely crap out very quickly if it ran full-time, and the expense of replacing it every 2 or 3 oil changes would more than offset any fuel economy savings.
They were great cars regarding global warming (due to their sipping of fuel)...but getting them clean enough to make Los Angeles happy on a bad day simply wasn’t humanly possible - so no more diesels (at least low-end diesels) for Americans.
“They were great cars regarding global warming (due to their sipping of fuel)...but getting them clean enough to make Los Angeles happy on a bad day simply wasn’t humanly possible - so no more diesels (at least low-end diesels) for Americans.”
The EPA standards are insanely stupid. It is passenger mile emmissions that matter, not parts per million.
So outlaw vehicles that get great passenger mile emissions, but put out a few percent more parts per million. Insanely stupid, typical EPA.