On Thu, 18 Apr 2013 13:33:01 -0400, Ed Huntress wrote:

On Thu, 18 Apr 2013 12:18:26 -0500, Tim Wescott
wrote:

On Thu, 18 Apr 2013 12:35:44 -0400, Ed Huntress wrote:

On Thu, 18 Apr 2013 11:08:52 -0500, Jon Elson
wrote:

Ed Huntress wrote:


FWIW, it looks to me like this engine violates a basic point of IC
engine design for thermal efficiency. By using a separate combustion
chamber, it multiplies the surface area relative to the volume of
combusted gas. The result is a very high ratio of lost heat to
useful heat.
Yes, I was thinking the same thing as soon as somebody brought up "how
do you cool it?" So, is the combustion chamber in the non-rotating
center?

It appears to be.

it seems like it has an intake/compression
piston and a power/exhaust piston.

Yeah, it's a split-cycle engine. But it doesn't appear to transfer the
unburned mixture to the power-piston chambers. Apparently it burns the
mixture first, in a separate chamber, and then opens a port from there
to a power-piston cylinder.

It's like a turbine engine with pistons doing the compressing and
delivering the power, rather than turbines. Or so it appears.

If there's also a separate combustion chamber, than that's THREE
places for heat loss!

Jon

Yes, with the separate combustion chamber being by far the biggest
one, because it not only is losing compression heat; it's also losing
heat of combustion.

There have been numerous split-cycle engines, including a number of
two-cylinder split-cycle motorcycles, and some were very successful.
They can combine pre-compression with as much supercharging as you
want.
But they compressed the mixture in one cylinder and transferred it to
the other, where it was burned. There must have been some thermal loss
inherent in the design but at least the *hot* gas was confined to the
power cylinder.

This one looks different. At first, when I read "split-cycle," I
thought is was really a conventional split-cycle with what amounts to
an external swash plate (there have been many swashplate and
wobble-plate engines, but they don't use an external cylinder to
handle the eccentric drive motion).

But the central combustion chamber make this one an entirely different
thing. I wonder why they do it that way? It may be necessary because
of the geometric relationships of the cylinders.

I wonder which is the Grand Inspiration that led to everything else --
the cylinder arrangement, or the combustion chamber arrangement?

Just guessing here, but I'd guess it was the balance and compactness
enabled by the radial configuration with the external cylinder for
transmitting power.

A rotary swashplate engine is more compact, but there is a rotating
rocking couple in the balance. I can't do the balance in my head on this
radial engine, but, at first glance, it does look inherently balanced.

I couldn't do the balance in my head either. I suspect that each
individual cylinder isn't perfectly balanced, but that the whole shebang
comes pretty close.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com