This video pretty much says it all.

[newbie123]

So far   it seems Hydrogen boosted Diesels are the way to go. 

[newbie123]

Braking energy regeneration is already in place in hybrid vehicles.  As for recapture of wasted heat, well, it's a complicated process.

Brake energy recovery could have been here 30+ years ago, it's not a new concept.

Why is waste heat recovery a complicated process? 

What I'm saying is there hasn't been a real objective for car companies (+oil and gov), (and public) to improve fuel economy up until like 2 years ago...  4 years ago 10mpg SUVs were getting pushed to the public. 

And if you think automakers have dumped all sorts of money into fuel efficiency you're nuts.  They care about one thing: money.

[WilbyInebriated]

They sell the devices to everybody.  What are they supposed to do when someone buys them, say no?

As far as the other effects you mentioned.  Just think about what you are saying for a second.  Do you know how many millions of manhours have been spent by car companies trying to figure out the most efficient way to build an engine?  Do you think that something as simple as cooling or changing the pressure in the cylinder has been overlooked?  If it was that simple to increase fuel mileage by the amounts claimed, every car maker would be doing it.

think about what you are saying for a second... yes they may have spent many hours figuring out the most efficient way to BUILD an engine but that does NOT make it the most efficient engine by any stretch of your imagination. they spend very little time trying to build a more efficient engine. its NOT what the public wants. the public wants monster SUV's and hummers.
race teams research, design and build more efficient engines, not the automakers that spew out whatever they have convinced the public to want via their feedback loop of television.

there is something fishy here. why is there no braking regeneration in non hybrids? economically viable way to make use of waste heat?  try a sterling or a peltier device...
of course it's that simple, the problem is is that the auto manufacturers don't pay your gas bill or electric bill so they really don't care. they are not interested in spending a couple hundred extra dollars per vehicle in the manufacture if they don't have to.
the computers are not hard to reprogram, i can do it in your garage with a laptop.
again i have to ask you utilitarian if you just talk a lot or if you have ever actually built something. it is clear you don't have much 'hands on' knowledge about automobiles.

google McMullen’s 1959 Opel P-1 Hardtop... 376.59 m.p.g.  IN 1973!!!

[Haliburton]

hey i have a 1969 opel GT for sale 500 bucks obo

[hydrocontrol]

think about what you are saying for a second... yes they may have spent many hours figuring out the most efficient way to BUILD an engine but that does NOT make it the most efficient engine by any stretch of your imagination. they spend very little time trying to build a more efficient engine. its NOT what the public wants. the public wants monster SUV's and hummers.
race teams research, design and build more efficient engines, not the automakers that spew out whatever they have convinced the public to want via their feedback loop of television.

What you state is so true... Even then race teams are limited in what they can design and build in order to fit into the 'racing rules'. There are a lot better and efficient engine designs such as the Bourke engine.
http://www.bourke-engine.com/

The auto industry does not want to build more efficient engines. Not in their interest as it would 'cost them money' and it would cost their bed buddies the oil companies in less revenue from selling less gas. Not going to happen in the US for awhile. Now maybe a country like Japan that has to import almost all their oil..  Oh wait.. they are producing more efficient engines and hybrids as well. Too bad the US auto makers can not get a clue. Maybe they will get a clue after all their sales go flat but then the government will likely bail them out. A shame..