CAPFlyer wrote:
The problem is that while we've not moved forward in efficiency, we've continued to add on more and more emissions controls, all of which siphon off power and in turn, fuel efficiency. The funniest part is that our biggest advancement in emissions control has also resulted in the worst reduction in fuel efficiency - the catalytic converter. I've heard figures of anywhere from 10% to 25% reduction, but most mechanics I've talked to agree it's more like 10-15% reduction. It's just an inefficient way to clean the exhaust that would be better done through cleaner fuels and better combustion controls. It doesn't help that we continue to degrade the quality of our fuel and allow more and more contamination to the fuel in the form of ethanol and additives that reduce the ability of the fuel to completely burn.
I agree. It's also weight related. With mandatory side airbags, 5mph bumpers, safety hoops, etc., we add weight. Lightweight manufacturing of components only goes so far to offset this.
Another factor is performance. There is a minimum fuel quantity required for a given horsepower - no matter how efficient you are. Granted, a new-tech computer management engine putting out 200hp burns less fuel than an old-tech carb & points engine putting out 200hp in most cases, but there is a practical minimum for that 200hp. As consumers demand more performance, we lose mpg even though engine efficiency is improved...