Rotary Internal-Combustion Engines. |
Updated: 15 May 2008 |
Rotary internal-combustion engine proposals exist in their hundreds, if not their thousands. The similarity with the rotary steam engine in the past is hard to ignore, the difference being of course that in this case a rotary engine achieved some success, in the shape of the Wankel , even if if it took a huge amount of development to get there.
If you have looked at my page on rotary steam engines, you will know that even with steam the problems of sealing and efficiency were severe. Things must surely be an order more difficult in a rotary internal combustion engine, where the pressures and temperatures are much higher.
THE ENGINES
This web page does not even attempt to provide a comprehensive list of the many rotary internal combustion designs that were promoted, as there are simply too many of them. The list here starts from about 1960; there were many proposals before that date, but I currently have none to hand. The dates given here are not necessarily the date on which the proposal was made public, the patent was filed, or anything else precise. It simply means that the project was being actively developed and promoted at that time. Since in most cases I have no information on the current status of most of these projects, I have used the present tense throughout.
What this page does try to do is to provide a starting point for those wishing to further investigate this field. Below, I have tried to classify those engines that are known to me by operating principle. Very possibly I have got some of them wrong. If you think so, or if you know of any good rotary IC engines that should be here, please let me know...
The list below links you to details of the engine, where such details exist on the page. It does not pretend to be a complete list. More engines will be added in time, but probably rather slowly. You know how it is. Of course you do.
Please ignore the #-numbers, this is just a filing system that attempts to keep all this organised.
THE KAUERTZ ENGINE: 1967.
 | Left: The Kauertz engine: 1967.
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 | Left: The Kauertz engine: 1967.
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One objection to the Kauertz engine is the high inertial loadings on the vanes as they accelerate and decelerate; these are transmitted to rather flimsy-looking linkages. And there seems likely to be sealing issues, as with all rotary engines.
 | Left: The Virmel engine: 1966.
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 | Left: The Virmel engine: 1966.
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As with the Kauertz engine, there looks to be high inertial loadings on the piston vanes as they accelerate and decelerate; once again these forces are transmitted to flimsy-looking linkages.
THE TSCHUDI ENGINE: 1967
Originator: Traugott Tschudi (Swiss). Work began on the engine in 1927.
 | Left: The Tschudi engine: 1967.
I don't pretend to understand how that is supposed to work, or how the pistons are sealed. |
 | Left: The operation of the Tschudi engine: 1967.
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An obvious objection is that the stresses on the rollers and cams are going to be high.
Unlike the Kauertz engine, the Tschudi only gives two power impulses for each revolution of the output shaft, and so a practical design requires two toroid assemblies, greatly complicating things.
THE BRADSHAW OMEGA ENGINE: 1955
 | Left: The Bradshaw Omega engine: 1955.
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 | Left: The Bradshaw engine principle.
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 | Left: Granville Bradshaw.
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According to one commentator from the world of motorcycles:
"The Omega was the final fling of a man whose ideas were always clever and innovative, but who sadly failed to understand the commercial needs of the business. His designs were novel, but invariably costly and seldom trouble-free, so his long involvement with the industry made news and kept everyone intrigued, rather than producing machines for riding."
It appears his aeroplane engines were also problematic: see Wikipedia.
I unearthed this quote from Patrick Head, one of the great engineers of Grand Prix racing:
"They had a wonderful project while I was down at Harry Westlake's. Somebody had sent them an engine called a Bradshaw, and it arrived in a cardboard box. It was basically a toroidal chamber with pistons which filled a section of the toroid, attached to two crosses, such that, as they went round, gearing superimposed an oscillation on the rotary motion. Intakes, exhaust and spark plugs were arranged around the periphery of the chamber. I was asked to find out how this engine worked, assemble it and install it on a dynamometer so that it could be evaluated.
"There was no inlet manifold or carburettor, so I got an Amal and made an inlet manifold, assembled the whole contraption and put it on the dyno. It happened that Dan Gurney turned up on the day we were due to start it up, and watched from outside the dyno. room, behind the bullet-proof glass. Anyway, this Bradshaw engine started up - the guy had said that it was perfectly balanced and would rev. to umpteen thousand RPM - the only problem was that in the gear casing, at the back of the engine, he had made all the gears himself, with a file or something! The pitch of the teeth were all irregular and I had to do an incredible amount of lapping - the quality of build was awful.
"Anyway it did start and run, and I fiddled about with the carburettor and sorted out a few things. Dan Gurney was outside and encouraging us to give it the berries. While it was idling at a few hundred RPM a cloud of smoke gradually built up in the dyno. room. Eventually we gave it some more RPM, only about 2,500, when suddenly there was a mighty BANG! and the whole of the glass window disappeared in a mess of oil and metal. Slowly the murk cleared and all we could see through the smoke were the feet of the gearcase, and the toroidal chamber, with bits of cast iron and aluminium all over the place.
"It all got collected up, put back in the box and sent back to Mr Bradshaw. I don't think his concept was properly evaluated at all....."
THE UMPLEBY ENGINE: 1908
Originator: Umpleby (England)
 | Left: The Umpleby engine: 1908
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THE SARICH ORBITAL ENGINE: 1972
Originator: Ralph Sarich (Perth, Australia)
This design gathered a lot of publicity in its day; See the Wikipedia page. (external link)
The Sarich Orbital engine had a number of fundamental and unsolved problems kept it from becoming a practical engine. Amongst these are key components that cannot be cooled and others that cannot readily be lubricated; it is very susceptible to overheating. To which we might add the usual sealing problems.
See United States Patent 4,037,997, "Orbital Engine With Stabilizing Plate", published 1977
THE CHAPMAN ORBITAL ENGINE: 1973
Originator: Howard R Chapman (California, USA)
This engine should not strictly be in this gallery of the museum as it was not an IC engine, though it was closely associated with them; it was a "steam engine" powered by Freon. It was intended as part of a bottoming cycle to improve the efficiency of conventional IC engines.
Since it is fundamentally a steam engine, it is to be found in the Rotary Steam Engine gallery, here.
See United States Patent 3,743,451, "Rotary Engine", published 1973
THE MERCER CAM ENGINE.
REVOLVING-BLOCK ENGINES
 | Left: The Mercer Cam engine: 1964.
In the diagram, cylinders 2 and 4 have just fired and cylinders 1 and 3 have reached the end of their power strokes, and are taking in fresh petrol/air via the central rotary valve (a blower is necessary between carburettor and engine to make this happen) as the exhaust exits. It is essentially a two-stroke cycle with each cylinder giving two power strokes per revolution. The Ljungström "Crankless" Steam Engine of 1900. |
THE MURRAY ROTORCAM.
 | Left: The Murray Rotorcam: 1991.
The Ljungström "Crankless" Steam Engine of 1900. |
THE SIDDONS S-ENGINE.
 | Left: The Siddons S-engine: 1969
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SOME PATENTS
A huge number of patents for rotary IC engines have been registered. Here is a random sample.
US 2 927 560
US 2 958 312
CURRENT ROTARY IC ENGINE ACTIVITY.
These are external links; not responsible for the content of external sites. Some of these links are currently dead but are retained here as their titles are the only clue to tracking them down.
The Rand Cam Engine. Dead link
The Antonio Sanchez Hybrid Engine (Spain)
The Dyna-Cam Engine Dead link
The Perlex Engine Dead link
The Rotary of Koushi Akasaka (Japan)
  
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