Dynamic balancing the rhombic Stirling engine on the test bench

[@Sammy-eb2cy]

Thank you for the details with your experiences. Very helpful to the understanding of the complexity of the Stirling. I wish you success!

[@myengines2443]

Thanks!

[@dedicateddilettante]

Keep it up! One day I hope to have the machinery to replicate and keep the work going!

[@myengines2443]

That would be very interesting.. thanks for your kind comment!

[@tudedude]

Thanks for the updates on your progress, great stuff 🙂

[@myengines2443]

Thanks

[@carlossol999]

I know you mentioned that it takes more time and effort to record your voice but I'm glad it's back 😄😄

[@IronGoober]

Agreed. I like knowing the voice behind all of this hard work.

[@myengines2443]

Thanks

[@turbowidget]

For the piston sealing it may be useful to explore large compressor sealing ring materials. We machine a material called Enflon into rider bans for compressors. This is a graphite / carbon filled teflon material. It has some great properties and can be used for energized rings with wave springs inside. Another material that may be useful is called graphalloy. Its made by the graphite metalizing company. They make various compounds suitable for dry running at higher temperatures. I would love to build a large stirling. Maybe when i retire and i have time to play!😃 good luck!

[@myengines2443]

Thanks for your proposals I am looking always for materials to improve the sealing with low friction. I tried a lot materials and at the moment I a very happy with the tribological plastic Igus W300. Many thanks, I will research your thoughts.

[@turbowidget]

@@myengines2443 if you would like to share emails i can send you some links to materials we have used in self lubricating dry applications

[@supercoe]

Great work!

[@myengines2443]

Thanks!

[@Lechoslowianin]

I have a problem with calculating whether the thermal transmittance in the engine of my design is sufficient due to the material I used. Could you take a look at it and give your opinion?

[@StanislavZachazevski]

Hello. I can run you numbers using some matlab code.

[@myengines2443]

I used the FEA method for it, it can be mad with free programs like Ansys (demo) or Freecad. I look at your problems soon and will comment! Greetings

[@ZURAD]

Would better heat sinking help at all? Really interesting!

[@BasementEngineer]

Ice water for cooling the engine would improve efficiency and power output. This experiment was conducted on the little engine you may view on my channel, where it runs a portable transistor radio. Ice water made a difference! As would higher temperatures at the hot end. Fact is that limitations for both are dictated by the ambient temperature for cooling purposes, and the metallurgical temperature limit for the hot end. Apart from that the optimization of the 2 heat exchangers has a great impact on the power and efficiency of the STIRLING engine. (note the spelling!) This is the reason why this type of engine does NOT lend itself to simply scaling up all dimendions in order to produce a more powerful engine. Each engine size and working gas needs optimization for greatest efficiency and power. The author of this post went to great lengths to produce good heat exchangers for his engine and is to be commended for his work. The next step towards greater power output would be to pressurize this engine with helium gas or, better yet, hydrogen gas. Pressurized to say 10 atmospheres, depending on the robustness of the design and manufacture, it would be interesting to observe the difference in performance between the two gasses in the same engine at the same pressure. Personally I have experimented with helium, and found a great increase in engine power from pressurizing with air. I think the author would be surprised at the increase in engine power output. I observed a 3x increase in power output with helium at 100 psi pressure or so. With air pressurization I found that the performance decreased at pressures greater than 35 psi or so. To increase thermodynamic efficiency the next step would be to use the exhaust gas from the burner to pre-heat the combustion air drawn into the burner.

[@myengines2443]

You cant see it very well in the video but on the back of the test bench is an car cooler and a water is pumped through the cooler. At high power the cooling water reaches about 50 degrees celsius. Of course cooler water would be better but not practical and economic I think. Thanks for your nice comment!

[@myengines2443]

Exactly, the temperature difference is important. I also made experiments with ice water and performance raised but it is not practical and not economical! Thanks for your input!

[@kipminnameier5870]

Have you heard of The Whispergen motor

[@myengines2443]

Yes sure but at the moment I try some other concept. Maybe I will put more focus on its principle in the future, thanks!

[@kipminnameier5870]

@myengines2443 The Whisper Jen motor is amazing for some reason they discontinued it I have been looking for one that I can modify I want to change the fuel source

[@jgbstirling6938]

I have two wisppergen engine in my workshop the only country that have made 4000 wispergen engines is Spain in a factory from Mondragon group . 200 km from my house.

[@myengines2443]

The whispergen is really a legenday engine, very nice to own them! At the moment on ebay UK is a Philips MP1002 Genset for sale from barumman (youtube stirling legend) thats really tempting... Thanks for your kind comment

[@StanislavZachazevski]

Hello. So - could write which math finally worked ? Thank for testing with more and less weight.

[@myengines2443]

I just used the formulas from the 1. balancing video, they are right from both sources and my balancing experiments seem to confirm it.

[@sierraecho884]

Your test stand, engineering and so on is great but I don´t think that this is the right way. I much rather would like to have a more simple machine with less moving parts instead of "German over-engineering" the thing. Why didn´t you choose a free piston beta configuration with a membrane instead for instance ? The gear drive alone is a nightmare, even if you get it to run properly at a certain price point this just does not make any sense. Less parts, less friction, less weight, all in all simpler should be the goal. Being an automotive R&D engineer myself I know how hard it is to create a product like that. I really hope you either reevaluate or you have some decision matrix why you chose this configuration instead which you maybe can show us, because otherwise I really don´t understand.

[@ieatYTP59]

he should not choose a free piston but a lamina flow wich is the perfect mix between the free piston and the rhombic, just like this engine : kzbin.info/www/bejne/g2rEhpyln9mYr9U PLEASE GUYS DON'T stop to promote Stirling engines and to work on it, because they don't want us to know, this engine could change the world

[@myengines2443]

Yes you are right, but I want to get in the region of 1 KW output. This calls for high pressure (10 bar with this engine) or a very big engine. You know the sunpulse engine? It follows your concept but is very big. I like the concept of the early Philips engines very much, and of course a prototype engine is often much more complicated than it has to be. First I want to reach the power and efficiency I need and then make it more simple. I am always looking for ways to make it more simple or use a more simple concept but it seems not easy to me... Thanks for your nice arguments, I am also very interested in more easy concepts like thermoacoustic or thermal lag engines but I am not sure about their potential of generating higher power. I look forward to some suggestions for simpler engines of you that would be nice.... Greetings

[@myengines2443]

The thermoacoustic and thermal lag engines are very interesting and I researched a bit about them but I am unsure about their potential... Thanks for your comment

[@ieatYTP59]

@@myengines2443 the whispergen 1kw stirlîng engine was a 4 pistons thermal lag engine, whispergen is closed now but I'm trying to remake one with a car ac compressor, its the same mechanism

[@sierraecho884]

@@myengines2443 I too like the Philips engine, but this is many decades old tech by this point, it´s a fine idea but it´s basically post WW2. It was great at it´s time, but this time has passed. Today with CAD, CAM, rapid prototyping (you can sinter parts in metal and make them more efficient due to better geometry for cooling or heat transfer) and so on, something a lot better must be possible. The beta configuration is a good idea but in my opinion the free piston is it´s logical descendent, since it takes the same basic idea but get´s rid of all the linkages. You can also load it with helium under pressure. You can still improve the regenerator and all that. In my opinion your idea will fail due to the complexity of the linkages and the precision of manufacturing. Your engine is probably the best "hobby" made engine on all of KZbin, performance and quality wise, but costs wise ? Other 1-3Kw Stirling engines use the free piston design, maybe take them as a example. I think their efficiency is way better just because there are no gears, links nothing. Swiss company made for a combined heat and power unit. Archiving the same result but with less this is true engineering and very very hard. Imagine the AK47 compared to modern firearms. Even a 14 year old can use the AK and it always works, it´s also cheap and still it´s useful within 200m combat range (which most combat takes place) it´s not better in any way than other firearms but it´s cheap and it delivers, this is basically the kind of engineering one would need for a breakthrough in Stirling engine tech. for home use.