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Originally Posted by Dean
Yes, there have been incremental improvements over that time, mostly advancements in the technologies I described, I am not saying there wern't.
Variable valve timing has significantly improved the power and that is one technology that has been productionized in that time, but I can't think of another that made a significant impact on fuel economy. Can you?
I also agree on the industry's focus.
Oh, and diesel's are another example of slower reciprocating and revolving parts being more efficient...
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VVT, turbos and superchargers are all excellent methods of increasing fuel mileage. They're just tuned for power instead. But again, those aren't new technologies... hell the turbo is as old as the internal combustion engine. What's made them so much better is the computer control of boost, fuel and timing. Look at the old Mustang SVO (4 cylinder turbo), and the other turbo cars from that era: GNX, Omni GLHS, Star/Quest, Turbo-II RX-7, etc. They all used brute force turbo induction... set the wastegate and have at it w/ a strong/heavy block. They made great power for the era (1980's), but also had reliability issues, and didn't even pretend to be fuel efficient.
Today's turbo motors are far more fragile in construction, but are far more reliable due to computer control of fuel and timing, dynamic boost control, VVT control, knock sensors, EGT sensors, A/F sensors, etc. So they can make more power, get better mileage, pass stricter emissions requirements, and weigh less (though the cars they're put in are heavier due to modern crash regulations).
On the immediate horizon we've got direct injection, individual cylinder throttle control, and better fuels that will take the same "basic" technology to even higher performance levels, both power and mileage-wise.
The piston combustion motor still has some life left in it yet.