a friend of mine works for volvo, engine/drive technology, in sweden, i asked him, and he said something like:
“you get better fuel consumption by increasing fuel injection pressures / engine temperatures, and recirculating some of the exhaust to improve nucleation’
unfortunately, this increase amounts of NO, and very small carbon particulatas – fine soot – both of which are quite nasty, so Volvo don’t do it/don’t do much of it”
i might have all of that wrong, but it seems that increased fuel economy comes at the cost of exhaust nasties, which is what the swedish volvo types care about.
i can get about 45mpg from my V40… not great but good enough for an old engine that’s still lovely to drive.
i’ve just been reading about the Nissan leaf, i’ve been a bit sceptical about battery-cars, but the numbers seem to be starting to make sense.
it seems you can get 100 miles from a charge, then do it again after a half-hour quick-charge, which is sort of nearly how i do long drives anyway.
i’m honestly impressed.