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What the auto manufacturers have not done, or possibly do not want to do, is to build very high mileage cars that are inexpensive.
Better aero while still using over sized engines means it is almost impossible to make the larger engine maintain higher cruising speeds at decent BSFC rates.
Smaller engines can be made to provide the power necessary for small percentage periods of high sustained loads, like a 7 mile 7% grade while operating at best BSFC under level ground cruising speeds below 70 MPH.
Lower total final drive ratios are a step in the right direction, but the best power trains will allow cruising RPM ranges well below 1500, without restriction of air intake. The EPA projected that power train improvements especially in the area of short term capacitive storage and release of energy independent of engine operation, can double mileage averaged while not changing any other system components.
Better aero improves mileage, but it also reduces the load on the engine and therefore will reduce it's BSFC unless other systems are also refined to take advantage of the lower average total energy demands.
Steps currently being made by Ford, with automated manual transmissions like the dual clutch 6 speeds, and higher compression direct injected lower displacement engines are definitely a significant improvement, but the future is in Infinitely variable transmissions that allow independent engine on-off cycling at lower sustained speeds and still maintain high BSFC at higher sustained speeds by transitioning into a low RPM direct drive operational tactic.
The power train will also allow high efficiency (above 80%) regeneration of braking efforts by using the infinite gear ratios to produce stored energy all the way down to ) wheel speed.
Then the benefits of aero will be fully realized when the complete vehicle system is designed to maximise that benefit, which even at speeds as low as 30 MPH can still be significant when you have eliminated the throttle restriction necessary to make a 200 HP engine only produce 8 HP or less.
Of course when you consider the economic and employment effects of a $10k car that gets 80+ MPG average and virtually eliminates the reapir and maintenance industry, short sighted people will always use the analogy that the loss of jobs outweighs the benefits.
The same logic can be applied to every significant improvement in technology in the past.
A good example is the computer we all use to communicate on this forum and the internet itself. Certainly more people would be employed if we had to do this by snail mail and long distance phone calls using Maybelle the operator to switch you to a different phone exchange with your 5 digit phone number, while your wife hung the lanudry out to dry and the dishes were soaking in the sink waiting to be hand washed.
Why don't we just go back to the pre computer age for full employment.
regards
Mech
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