I'm a mechanical engineering student and I'm the energy coordinator for Engineers Without Borders Israel. I have a small budget for starting a stirling engine project for creating electricity (around 100w). I ordered an engine today from littlemachineshop.com and I plan to build a bigger one from steel or aluminium. It's a good idea to try and contact EWB engineers in the US to ask for help , and do this in Opensource form. all OS stirling engine projects ive seen on the web died down with little more than a few small models. Maybe we could make this work. I will probably start with 2 pistons and not 4. there is a french site that has plans to build a 200w model http://www.moteur-stirling.com/modeluk.htm this is the only complete reference I found
I send the sent you the following email and am also posting it here, if you don't mind.
- Tom Belpasso
Hi,
Thanks for the comments on my blog. Since I haven't actually gotten the prototype running yet I haven't specified what the target power output should be yet. I found a commercial product that is using pistons about the same size as mine that is suppose to produce at least 160W see: http://www.whispergen.com/main/technology/. They use an interesting piston seal that is dynamically pressurized to vary the resistance of the seal. It is also a 4 cylinder design but with a rocker drive.
Since returning from my trip, I have been working on software projects and haven't started working on the engine yet. I have a private dotproject site that I am using to track the tasks. My goal is to have a more public version available soon for project members to use. I am also upgrading my MediaWiki so I can also host a Wiki for the project. I am planning on keeping the Google based project site and blog for the more public aspects of the project and use my home based sites for real work, since they shouldn't get too much traffic.
As for the status of the engine, right now I think there is too much friction on the push rods. The cam is pushing them to side and it is making them bind in hole through the case. I have just bought a 5/8" drill bit, so I can enlarge the holes and fit a nylon sleeve bearing. I have not been using a lot of lubricants because it be too messy, since I have to routinely take the cylinder apart to replace the stupid polyethylene bags when the leak.
My longer term plan is to add guides for the push rods, to take the lateral forces from the push rod bearing. I have to get some additional tooling before I can make them. For now I will just add the bearing and see if that is enough to get it to run with the flywheel I currently have. I may have to add more weight to it so it can make it around. In fact that was why I decided to go for the full 4 cylinders, otherwise the force of the pistons under pressure would make it even harder to turn.
I am getting pissed off at these plastic people, I have requested samples from server sources and the never get back to me. Very unprofessional.
Good luck on you project, please send me links to the design you are using. Also if you want I can add you as a contributer to the Google site and you can make yourself a page. That's what it is for.
Tom, Not sure if you're still working on this, but you might check out www.bellofram.com for the piston seals. They seem to be exactly what you are looking for, but I'm not sure of prices. I've often considered using them on a Stirling engine but so far have not tried them.
This blog mainly for notes on the stuff I buy. Sometimes I will include some ideas about physics. I am also working on an Stirling engine, for official publications for the Open Stirling Engine project, please go to the Google web page: http://sites.google.com/site/openstirlingengine/Home
3 comments:
Hi there.
I'm a mechanical engineering student and I'm the energy coordinator for Engineers Without Borders Israel. I have a small budget for starting a stirling engine project for creating electricity (around 100w). I ordered an engine today from littlemachineshop.com and I plan to build a bigger one from steel or aluminium. It's a good idea to try and contact EWB engineers in the US to ask for help , and do this in Opensource form. all OS stirling engine projects ive seen on the web died down with little more than a few small models. Maybe we could make this work. I will probably start with 2 pistons and not 4. there is a french site that has plans to build a 200w model http://www.moteur-stirling.com/modeluk.htm this is the only complete reference I found
Please write back to Tomsofer@@@gmail.com
Hi Tom Sofer,
I send the sent you the following email and am also posting it here, if you don't mind.
- Tom Belpasso
Hi,
Thanks for the comments on my blog. Since I haven't actually gotten the prototype running yet I haven't specified what the target power output should be yet. I found a commercial product that is using pistons about the same size as mine that is suppose to produce at least 160W see: http://www.whispergen.com/main/technology/. They use an interesting piston seal that is dynamically pressurized to vary the resistance of the seal. It is also a 4 cylinder design but with a rocker drive.
Since returning from my trip, I have been working on software projects and haven't started working on the engine yet. I have a private dotproject site that I am using to track the tasks. My goal is to have a more public version available soon for project members to use. I am also upgrading my MediaWiki so I can also host a Wiki for the project. I am planning on keeping the Google based project site and blog for the more public aspects of the project and use my home based sites for real work, since they shouldn't get too much traffic.
As for the status of the engine, right now I think there is too much friction on the push rods. The cam is pushing them to side and it is making them bind in hole through the case. I have just bought a 5/8" drill bit, so I can enlarge the holes and fit a nylon sleeve bearing. I have not been using a lot of lubricants because it be too messy, since I have to routinely take the cylinder apart to replace the stupid polyethylene bags when the leak.
My longer term plan is to add guides for the push rods, to take the lateral forces from the push rod bearing. I have to get some additional tooling before I can make them. For now I will just add the bearing and see if that is enough to get it to run with the flywheel I currently have. I may have to add more weight to it so it can make it around. In fact that was why I decided to go for the full 4 cylinders, otherwise the force of the pistons under pressure would make it even harder to turn.
I am getting pissed off at these plastic people, I have requested samples from server sources and the never get back to me. Very unprofessional.
Good luck on you project, please send me links to the design you are using. Also if you want I can add you as a contributer to the Google site and you can make yourself a page. That's what it is for.
Thanks,
- Tom Belpasso
Tom,
Not sure if you're still working on this, but you might check out www.bellofram.com for the piston seals. They seem to be exactly what you are looking for, but I'm not sure of prices. I've often considered using them on a Stirling engine but so far have not tried them.
Cliff
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