All ceramic engine, 38% efficiency

[Dutcher]

I am seeking design engineering assistance and any other to build this design.

Burn = 1,000+ C

Exhaust + <100C

Heat losses minimal.

 

[franzh]

About 20 years ago I saw a REALLY big diesel engine manufacturer make a 4 cyl engine with mostly composite and ceramic parts, including valves, fire deck, pistons, cylinder liners, etc. and run it adiabatic mode. Total cooling system capacity was around 4 liters, and this was on a diesel engine with roughly 400 cid. When I saw the engine, it was on the dyno running at 50% load and about 1000 hours continuous. Your exhaust numbers are not feasible, at least with an IC engine.

The liners were so hard they had to be lapped with a diamond dust impregnated lapping bar.

I think it was an engineering exercise as it apparently never made it to production.

Good Luck!

Franz

 

[Dutcher]

As I feel that this design is of a potential to change the way we do tractive automotive business I am going to explain in more detail. I do this not to in any deminish my claim to the design.

I call the design the Sterling External Combustion Positive Displacement Steam Turbine. A mouth full.

On a common shaft are mounted a series of vane type air motors of ceramic. One provides charging air for the system. The next is linked by a sram jet burner with a very lean burn. This will progress in stages to develope a very hot compressed oxygen containing fluid stream which then goes into another series, but this time instead of fuel water in injected to produce the &quot;work&quot;.

Basicaly the front end is a high efficiency burner and the back is a low speed positive displacement steam turbine. Hence the low exhaust temp. The srams act as flash boilers with little residual energy. The best we have is the steam cycle to produce work from a fuel. The drawback is the boiler, as it is basically a bomb. Here I am useing the fluid velocity to have a boiler and no bomb.

I think it is a design that you say has one moving part.

This is simplicity itself and I want to build it. If you think that I have missed something and this will not work, please put me out of my misery trying to build it. If you can point me to any grants or would like involvment I welcome any input.

RDS

 

[ilprofessore]

Dutcher: It is indeed exciting to find someone who is looking &quot;outside the box&quot; for a new idea. My comments: First, if you referring to a Stirling Engine, it is by definition &quot;external combustion.&quot; Using a series of vane type air motors is a feasible approach since a Stirling has to operate at close to 1000 psig to get respectable efficiency. You might need 4 to 5 stages to get the required pressure. Stirlings operate better at higher pressures since the gas has heat transfer properties similar to a liquid at such high densities. If a series of air motors are required you will need valves (perhaps like a reed valve on a refrigerator compressor) to isolate each section. Next, if you are using a positive displacement air motor it wouldn’t be called a &quot;steam turbine,&quot; and if it operates on a mixture of air and steam it would be more like a Stirling engine that a steam turbine. I assume that you will not be condensing the steam and will require a makeup water stream. But then if the working gas is not recycled, it’s not a Stirling.

Refer to the article about the commercially available Stirling in October 2001 Power Engineering. If you look at the cutaway drawing, you will notice a sophisticated-looking recuperator to reclaim the rejected heat which is then used to preheat the combustion air to improve engine efficiency. What the photo doesn’t reveal is the high temperature materials required for such high efficiency. Remember ceramics do't transfer heat as well as metals. Go to the manufacturer’s web site for more info. They don’t use steam augmentation since the condensed (or makeup) water would have to be pumped up to the &quot;boiler drum&quot; pressure, and this would be another relatively complex subsystem to and otherwise simple flow schematic.