[Tigers] Gas Mileage & diesels

[Stephen Waybright]

As I recall (and this is more contextual memory than factual after all
the years since my thermodynamics classes) Diesel fuel has less
specific energy, which is why they are not very powerful without a
turbo, but the very high compression combustion significantly increases
thermal effeciency.

Someone mentioned the high power, high efficiency Smokey Yunick car at
the upcoming Russo & steele auction... When that car was first covered
in Popular Mechanics back in the 80's I tried to model the termal cycle
to figure out how this thing could possibly work (at least
theoretically). I ended up playing with thermal cycles that used a
turbo to compress some crazy ratios (>35:1 if I recall, maybe as high
as 60:1) to get the kind of efficieny his engine was claiming, but none
of the magazine info reflected an engine that could endure that kind of
pressure. I may have to bid on it to finally verify my theories these
20+ years later!

Stephen Waybright

--- Scott Hutchinson <shutchin at netjets.com> wrote:

> 
> Here's a question for you engineer types. Is the diesel engine more
> efficient, or does diesel fuel just have more energy in it?.