Re: max gas mileage

["John S. Denker" <jsd@MONMOUTH.COM>]

At 11:17 AM 2/21/01 -0400, Tim O'Donnell wrote:
> > 100 mpg carburetor.
>
> Actually isn't that around the upper limit if gasoline could
> be 100 % converted to mechanical energy.

Upper limit for what?  We need some context here, to make the dimensional
analysis come out right, if nothing else.

A bus in stop-and-go traffic will never achieve 100 mpg.

A moped cruising without interference can easily exceed 100 mpg today.

If we want to compare apples to apples, we might start by thinking about
miles per gallon per ton, at a certain speed.  Even then we would have a
number that would be hard to interpret, because it doesn't scale very well
(large, dense things would do better than light, roomy things) and it would
be super-sensitive to driving patterns (stop-and-go or otherwise).

==================

One of my favorite things to think about is caravanning:  Imagine the cars
of the future, with super reliability and all sorts of sonar and
microprocessors and infrastructure support.  Upon entering the highway, the
autopilot would attach the car to a caravan with 100 or so others moving at
80 mph, all bumper-to-bumper.  Perhaps they would be physically joined like
a railroad train, perhaps not.

With proper aerodynamic fairings you could greatly reduce air drag.
With proper synchronization with cross traffic, you could avoid the
losses associated with stop-and-go.

Packing them bumper-to-bumper would also greatly improve the flux, i.e. the
carrying capacity of a given amount of road.