Volt-less

[luvin honey]

Even if the system for mpg changed, my old Saturn got 40 mpg for 16 years. My newer (2010) small Toyota gets 35 on a good week. Even the newer Saturns didn't get the mpg that the old ones did, same model.

[BlueBee]

Well there are lots of factors that affect mpg beyond the emissions systems.   Did they have manual or auto trans, what was the final gear ratios, what was the coefficient of drag, were you driving at the same speeds?  Driving faster really eats away at MPG.  Etc, etc, etc.  

Because the engine control systems have become better over the years (more powerful CPUs, sensors, algorithms, etc) less raw pollution leaves the cylinders than ever before.  This lessons the work that a catalytic converter has to do and allows them to flow exhaust more freely than in years past.  Yes, restricting exhaust flow in any fashion will increase backpressure and lower the thermal efficiency of the engine, but I would contend this is not a significant loss anymore.  Other factors have a bigger affect on mpg.  

There’s not a whole lot more that can be done to improve gasoline engine efficiencies.  There are no more magic bullets left in the engine.  Most of the gains in the future, to get to Obama’s new 54mpg CAFÉ law, will come in the form of smaller profile cars.  Get used to it.    Small is in our future!  

[SEEYA]

>>There’s not a whole lot more that can be done to improve gasoline engine efficiencies.  There are no more magic bullets left
>>in the engine.

What about the 6 cycle engine?
[the usual 4 cycles: intake, compression, power, exhaust; then, water injection (causing steam) another power stroke and then another exhaust stroke]
 
Would the EPA allow it? Would the consumer accept the extra effort? 

[BlueBee]

6 cycles!  Wow.

Bigger sounds better, but the more cycles you have the less power per weight you get out.  2 cycles are so attractive because of the higher power to weight ratio.  I’ll have to admit I’ve never heard of a 6 cycle engine.  Interesting.  I assume the idea would be to harvest some of the residual heat energy to make it do work, right?  As Buzz pointed out, most of the chemical energy in the gasoline gets converted to waste heat.  If there was just some good way to harvest low grade heat energy.... 

I would bet a water cycle would not be good for emissions or the engine oil!  Combustion in the cylinders never makes it all the way to the walls because the walls are too cool as it is.  Yes too cool!  Combustion is quenched just short of the walls and that quench zone is an area that generates hydrocarbon emissions.  If you make the quench zone bigger by cooling off the combustion chamber with water, you’re probably going in the wrong direction for emissions.

Bill Gates thinks less cycles is better.  Did you see his investment in Ecomotors?
http://venturebeat.com/2010/07/13/bill-gates-backs-ecomotors-new-opoc-engine-with-23-5m/

The Aussies have been trying to perfect emissions on 2 cycle engines forever, but never succeeded.  Gates might have gotten this one wrong?