[bwilson4web]

Found an interesting post in USENET to complement this thread. In particular, the first link

Originally Posted by Bruce_Richmond

Funny, I just used some of the same links in a discussion in
alt.global-warming.
Should switch gasoline to 100% ethanol/You switch, retard. - alt.global-warming | Google Groups

(This included a useful engine calculator:
Power Cycle Analysis Online Calculator ...
This allows folks to change different ICE parameters and see the effect. rjw)

I agree the p-v chart is wrong and the normal transition can be seen
in figure 3.8 of your previous link.
http://web.mit.edu/16.unified/www/SP...oIdeal_web.jpg

The horizontal line from 3 to 4 is usually used in the cycle of a
diesel. The rational is that in a gasoline engine the fuel burns
almost instantly giving a vertical line for the rise in pressure.
With the diesel the fuel is injected over a period of time which
mantains a constant pressure during the first part of the power
stroke. Here is a p-v diagram for an Atkinson diesel:
Ern's Blog

Here is an article that gives some info about how the Atkinson cycle
is applied to the Prius.
Hybrid Tech - Honda's Insight and Toyota's Prius - page 2 | Automotive Industries

I also found out that a true Atkinson cycle engine involves more than
just variable valve timing, it actually changes the lengths of the
strokes, thus avoiding the pumping losses of drawing air in and then
pumping it out before closing the intake valve.
Animated Engines, Atkinson

Still the valve timing trick is a lot better than nothing.

Some of the articles are a little dated such as the 1.5L Prius engine analysis. Still, it is a good collection of URLs . . . Thanks to Bruce Richmond.

Bob Wilson