50MPG? Banned in the US

How would you like to have a car which gets better than 50 miles per gallon? Such cars exist, and are actually rather common in Europe. Why aren’t they sold here? They are essentially illegal, thanks to some very tight regulation. They are diesels, and as such run in Europe on a fuel which by law includes 15% minimum biofuel, a renewable resource.

But efficient engines like this run at higher temperatures and pressures, meaning they essentially burn a little nitrogen and thus produce more Nitrous Oxide, or NOx.

This is at the heart of the infamous Volkswagen “cheating scandal”, which was indeed a terrible moment. But now that Chevrolet’s small diesels may be guilty of the same thing, it’s worth talking about.

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