Actually, you don't need to disagree, since I didn't say the Otto had better efficiencyl I said that it would be more 'cost-effective' power source today and in the immediate future.

I believe that these engines will be cost-effective because manufacturers are so darn good at making millions of them rather inexpensively, and they serve us quite well.

The best way to conserve fuel without requiring exotic engines is to drive less, combine trips, drive no faster than the vehicle's optimum speed, take a few passengers alone, etc.

A better way to conserve fuel is to pool resources. Can you say carpool?

Buses, trains and airplanes are better at moving people with fuel, but all of the people have to agree to go together and leave and arrive at the same time.

Shoot, my Suburban, which struggles to get 16 mpg on the highway, can do the work of 2 cars if I share, and will use the same amount of gasoline as 2 cars getting 32 mpg with one person in each! Just think how much could be saved if there are 4 aboard!

Thanks to all for a very stimulating and educational discussion.

Best Regards,
Jim