Welcome to the party!
I had the idea of gasoline direct injection located in the center of the cylinder, when I took a long look at Diesel and Otto engine designs. It seemed to be the logical way to get the fuel consumption and emissions of gasoline engines reduced. I also figured compression to be about 13:1. Also other types of fuels (alcohol, natural gas, etc) will run cleaner and more efficiently.
That was 25 years ago! Naturally, who would listen to an accountant/computer programmer to solve 'engineering' problems.

I recently followed a link from this site to www.cyclonepower.com and was quite surprised to find out that there is an external combustion engine that will run on virtually any fuel, is 36% efficient, lighter weight than comparable HP ICE, low cost to manufacture, etc. Could some of you motorheads please tell me what I'm missing here? If this engine is for real, and it did win a prestigeous Popular Science award, why continue to screw around with ICEs?

Electric valves should be a requirement of all car engines as suggested yesterday. Now they need to add the air-hybrid part. They can also get rid of the starting motor with a bit of cleverness. Any innovation in automobile technology can only be done with the full support of the regulators and the automobile companies no matter how good the idea. Remember the EV1! And the Tesla. ..HG..

e. A Stoddard engine work seemly to the Rankine cycle but with gas. unlike a Sterling you have throttle control and placement of the heat exchangers. is best type of external heat engine to combine with gas or diesel. both engines can be built in one block. The water jackets become gas jackets. The gas jackets serve as the hot air exchanger. the radiator is still there but full of gas and not water.

It looks likely that this will compare well against CO2 emissions Astra diesel, CTDI @ 119g/kg.
Greater improvements over time plus other emissions issues that we normally associate with diesels plus cheaper fuel and ? manufacturing costs.

I'm not a spammer and I frequently contribute to this site. I'm still puzzled by the cyclone engine because it appears to me that they have solved some operational problems with steam/Rankin cycle that make this quite interesting. The engine uses virtually ANY fuel because it is external combustion. It operates at 36% efficiency and apparently has a reasonable production cost($100 per KW). If it is used as a genset you can also recover heat easily giving it an overall efficiency of over 80%. It was recently shown at a conference in Chicago. The 10 KW output can be measured easily, the BTU fuel input can be measured...how do you figure it's a scam? Exactly what data is being misrepresented?

The thing that is being misrepresented about the Cyclone engine ... is its thermal efficiency. NO WAY will a simple Rankine cycle approach 36% overall efficiency (fuel input to shaft power output). It cannot be (with reasonable high-side and low-side temperatures), and the proof is in the steam tables in any thermodynamics textbook.

I do not care what the manufacturer claims. I care only about the facts. If Cyclonepower finds a way to integrate the multiple stages of expansion and multiple stages of re-heat, plus feed-water pre-heat and boiler waste heat recuperation, ALL of which are implemented in large central power station plants (and which allow the theoretical efficiency to more closely approach the Carnot cycle limits) then more power to them. But that will be one extremely complex and expensive package. If you use the KISS approach (water into the boiler, boils, expands, into the condenser, to the water pump) then that is a simple Rankine cycle, and you don't get the high efficiency.

The multi-fuel capability seems scarcely to be an issue. It might have been an issue in the early 1900's, but not now.

One other thing ... continuous combustion does not exclude a combustion process from producing NOx and other products of combustion. If it is a lean-burn combustion stream (most boilers are), then you have the same NOx problem that you have with a diesel or lean-burn gasoline engine. If you run the boiler at stoichiometric, then it will be producing CO and HC and NOx, maybe not as much as a conventional gasoline engine but almost certainly above the prescribed limits, and then you'll need the same 3-way catalyst as a gasoline engine uses. Where is the advantage in this ... ? ? ?

One thing that's not commonly understood, but is apparent if one looks at the technology used in different applications, is that the optimum technology to do something on a 10 kW size range is not necessarily the same as to do it on a 100 MW size range. You can do things with a 100 MW central utility plant that are simply not feasible or even possible on a 10 kW device. For something on an automotive scale, using technology that we know how to do today, there isn't a more efficient powerplant than a diesel engine, although some spark-ignition units (like the one in this article) are coming close.

bud,

"So, what you are claiming then is that their 36% number is a misrepresentation?"

yes, that's exactly what he is stating. how many more times would you like him to repeat it? do the math yourself, you seem to be taking the manufacturers claims absolutely at face value, which is foolhardy no matter which way you look at it.

Actually not Eric, in fact design engineers always use the manufacturer's data to specify equipment. Whether it's HP from a pump curve, locked rotor amps for a blower motor, etc. The performance data always comes from the manufacturer. It doesn't make any difference that the Cyclone people are not a major manufacturer; there is no reason to treat them any differently than one UNLESS someone can site a specific example of misrepresentation. There is every reason to assume that they know how to measure KW output and BTU input and no reason to think that they are fabricating the data.

Looking over the web site I would think that the inventer (Schoell), who has 47 patents, just might know what he is doing.

Brian P
10% of the diesel cost at $3.60/gal would be $2.80 per million BTUs.

It doesn't have to be a liquid, it could be pulverized carbon, a carbon slurry (liquid), bio-methane (gas) or even pellets (solid) especially torrefied biomass made into pellets, or pyrolysis oil before upgrading. Isn't that the beauty of the external combustion, the fact that you can burn anything?

$2.80 is pretty cheap but it could be done with any carbon based waste or biomass that is torrefied or pelletized. The waste has a tipping fee associated with it which could be anywhere from $15 to $75 per ton. At $15 and using the RUF Bio-Brick process which can make pellets for $35 per ton (that includes all O&M and capital costs except feedstock, the capital cost for the $270,000 machine is 7 cents per MBTUs). so in this case the pellets cost $2 per MBTUs and revenue is $1 per MBTUs for a net of $1.

This fuel would be exempt from road tax, in fact there could be a carbon credit of $50 per ton of avoided fossil CO2.

There is over 18 quads of waste available in the US, PHEVs used for all personal transportation would require about 2 quads of transportation fuel and another 2.25 quads of electricity but that could come from renewable sources.

Prompted by this conversation, I cracked open my old Reynolds and Perkins thermo text, and in there, is a splendid example calculation for a simple Rankine cycle that has conditions not entirely different from what Cyclonepower quotes.

Hot side conditions 600 psia, superheat to 1000 F. Working fluid is water (steam).
Cold side conditions 80 F at saturation, the pressure is 0.5 psia at this temperature.
An assumption was made about the efficiency of the expander. I don't have the book in front of me but it was in the 80 - 90% range, which is quite possible for a *large* turbomachine.

The efficiency of this portion of the cycle was in the 36% range. BUT, and it's a big but, this does not include the efficiency of the boiler, nor of any parasitic losses (such as moving air across the condenser). So it's possible for a simple Rankine cycle to be in this efficiency range if you have a really good boiler with next to no losses (impossible in the real world). It will be absolutely necessary for the boiler to have almost 100% waste heat recuperation, because if you don't do that, you will be throwing heat up the chimney.

Now here's the problem when you try to translate this to an automotive application. Approaching 100% waste heat recuperation of the boiler exhaust requires a counterflow heat exchanger approaching infinite surface area. Approaching 80 F cold-side temperature requires an extremely large condenser surface area - for example, the radiator in a standard automobile is rejecting heat at approx 180 - 200 F and at only (approximately) half the amount of heat relative to power output compared to the amount that a Rankine cycle would have to reject.

Then there's the big one ... the expansion ratio. 600 psi on the hot side, 0.5 psi on the cold side. I forgot to look up the ratio of specific volumes; it's not quite as bad as the ratio of pressures but it's still rather extreme (back-of-notepad suggests around 400:1 volume ratio as opposed to 1200:1). In a large stationary power plant with a large number of turbine stages, where each one can have a reasonable pressure ratio across it to keep the volume increase manageable, and the pipe sizes can progressively increase, this is not a problem. To try to do this in a piston expander ... ! ! ! Even if it were a multi-stage expander, usually trying to expand all the way down to 0.5 psi results in requiring a large-displacement piston expander for the final stage, friction will usually make it not worthwhile to do so.

If Cyclonepower has found some trickery to get around some of this then more power to them, but when I look at it, I see a traditional simple Rankine cycle, and we as engineers know how to analyze the thermodynamics of those ...

Keep in mind that if the 36% is an "idealized" efficiency, then one ought to be comparing to an "idealized" Otto cycle efficiency, and no matter if the same temperature limits are chosen, or the same maximum operating pressures, or whatever, the Otto cycle will have a higher efficiency.

For you folks wanting to put crushed coal slurry into your vehicle fuel tank, I'd love to see how *that* is going to work. Particularly when it's -25 C and the water portion of the slurry has frozen. And how's your fly ash and desulfurization equipment ? ? ?

Who killed the electric car? Henry Ford did with his Model T. Internal combustion engines are the most compact power sources and the cheapest. They are very efficient, but fuel cells are more efficient and too much more expensive. The motor and drive electronics of an electric car are more expensive alone than an equivalent engine. A diesel-electric locomotive cost five to eight times an equivalent steam locomotive when the Chinese were still building both. ..HG..

@Brian P et al,
Appreciate all the thoughtful inputs, but please be reminded that the Cyclone engine is a new invention and not an ordinary old-fashioned steam engine. It utilizes super-heated water injection at 3000 psi into the expander instead of steam. The super-heated water at ~800 K will quickly turn into steam, but only a small portion of it, since steam requires a lot of heat input. The rest (most of it) of the heated water will remain in liquid form, to supply heat for the steam during the expansion stroke. This is analogous to the multiple re-heating stages of a steam turbine power plant, all wrapped up in a small and simple package. The use of heat transfer from the combuster to water instead of to steam as in steam super heating phase and reheating phase makes for a very compact design, low cost and very efficient heat transfer indeed, liquid to liquid instead of gas to gas. Likewise, heat recuperation will be from the hot remaining water into the cooler entering water instead of from steam to water, hence, liquid to liquid heat transfer.

36% overall thermal efficiency is very good, since steam engine like this one obviate the needs for transmission, thereby reducing further friction loss, AND, LOW-LOAD EFFICIENCY WILL LIKELY REMAIN CLOSE TO PEAK EFFICIENCY, when the steam will be expanded to below atmospheric pressure in the condenser. At higher power output and hence lower expansion ratio, the remaining heat in the steam and water can be recuperated back to the incoming cooler water going into the "boiler"...umm...there is not a boiler in this engine... Almost the efficiency tank-to-wheel of the Prius hybrid without all the complicated hardwares.