User:Qchi8375/enes100/engine

link to the team page:qjb-eng

Give instructor top 3 project choice list

 * ENGINES
 * ILLUMINATE CLOTHING
 * electric cars

Write problem statement
I will be working on a stirling engine. from the available designs,none of them could function as is expected of them. The main issue now is to seek out those issues which prevented them from working and design and construct one which is able to.Using tin can material, the cost should not be a problem.

Assign Task1
My task here will be to gather enough knowledge about how a proper stirling engine works if i am to able to begin making one. From the materials to the design i would like to make.

Compare actual work done to Task1

 * From the available workable engines i came across in storage, there actually seemed to be various common errors made at various parts.The main issue was to make a smooth running crankshaft so as to reduce the friction opposing the engines power as much as possible.This picture will show clearly the way the crankshaft is attached to the power stroke of the displacer

Week1 Narrative

 * The stirling engine happens to be one of the very best engines available, in terms of efficiency between the energy input and output. It functions as follows based on the information i was able to get.
 * In the case of the engine i an trying to make, i.e. a tin can stirling engine, the main source is heat from a fire. This heat is tasked with expanding the air inside a closed tin can. Once this air is fully expanded, the hot air tends to move upwards while the cold air sinks to be heated as well. This action alongside the upwards force of the expanding air tends to move the displacer piston . This movement has to be started with a slight push on the wheel.The displacer is usually equivalent to about half the displacer volume.
 * As the displacer moves up and down, the slight airways at the side of the displacer aloows for the air to be forced around in the opposite direction of the displacer. That is when the displacer moves down, the air is forced up. This air also helps to move the power piston hooked up to the crankshaft. This power piston is above the tin can but must remain air tight so as not to let the air inside the tin can escape. Escaping air reduces the pressure inside the can and thus reduces the engines efficiency.
 * the following [|engines video] shows how to begin construction of the stirling engine out of tin cans.*[|engines making tin stirling engines]


 * A tin can stirling engine needs to function with as little friction as possible. Between the crankshaft and all other moving parts, there must be a smooth transition for it to function.
 * Duel Assembly X-Section 4-5-11.jpg

Assign Task2
Now that all my parts are in place, i will continue by moving on to the assembly.

Compare actual work done to Task2
As far as the collection of parts was concerned, I was able to obtain a suitable tin can, some pvc pipes i found in storage made for a good power piston cylinder. The displacer rod was made out of a smoothed out hanger wire. for the displacer itself, i decided to use some styrofoam cut to fit on the insides of the tin can but the bottom area covered by some tin material. the crankshaft too is out of hanger wire.

Week2 Narrative

 * Well firstly there is the usual problem of trying to avoid as much friction as possible in the moving parts of the engine. This thereby meant that there was no way i could use a saw to cut the sides of the tin can. I thus used a pair of pliers as a saw would just go a long way to dent the sides of the tin can beneath the cut. With this dent, the friction is significantly increased. Also the hanger wire initially had some thin rubber coating around it.
 * Also the rubber wire had some thin rubber coating around it. Whenever i used it in this state inside the displacer, it tended to be quite difficult to move smoothly.I thus removed the protective coating by use of a knife. After doing this i also tried to smooth out the wire even more by scratching the knife's sharp edge along its length.
 * For the hole at the top of the engine's lid for the displacer wire to pass through, i tried to make it as small as i could be. Having a large hole at that point only means that a lot of the engine's air would be lost and this pressure loss would mean an inefficient engine. Like i wrote earlier, the displacer itself is made up of styrofoam sealed at the bottom by a flat and light tin material from a soda can. This is simply to allow mt displacer be as light as possible while still displacing the right amount of air for the engine to work. The tin at its bottom was just as a precaution should its bottom get too hot that the styrofoam could be melted. The displacer also was cut to be approximately half of the internal volume of the tin can.
 * For the power piston, i decided to use pvc pipes. this was mainly because they are very smooth on the interior and thus friction would not be an issue. Aso they are a lot easier to cut and attach. For the power pistons, which are to be at the top of the engine lid, i made them by using a simple technique. On the insides of the already cut pvc pipes, I layered it with some wax paper. I then poured epoxy so as to fill the holes to the very brim and set it out to dry. When fully dried. it was now easy to slide the epoxy block out and take off the wax paper. Now the good thing about this is that it fits perfectly into the power piston and so there is no issue trying to design a piston that fits.
 * [|engines how to prepare a stirling engine from tin cans]
 * [|engines making tin stirling engines]
 * Full Assembly Snapshot 3-29-11.jpg
 * Duel Displacer Full 4-5-11.jpg
 * Duel Assembly X-Section 4-5-11.jpg
 * Center Holes 4-5-11.jpg

Assign Task3
Record what you are planning on doing for the team during the weekend between week2 and week3 of the project here.

Compare actual work done to Task3
I began the construction of my engine after putting all the parts i had made together.

Week3 Narrative

 * Before i could start assembling my stirling engine, i had to first do the required calculations for the crankshaft. It is very tricky to make and so it took me quite a long time. First of all, u will want to have the displacer to be fully down while the power piston is at the very end of its oscillation. For this to be possible means that the rise of the crankshaft at the point of attachment of the displacer has to be about half the length of the tin can's interior. Also the power piston's rise at the crankshaft has to also be the same length. Also the rise for the power piston at the crankshaft has to be at an angle of 90 to that of the displacer. this is just to ensure that when they are working together, the displacer will be down as the power piston is up.
 * Also, I got it from Lloyd in class that not attaching the power and displacer piston to the crankshaft will go a long way to reduce the friction in the system. With this i decided to use hie idea to attach the pistons to some very thin pvc tubes which fit quite well with the size of my crankshaft wire. This tube is quite able to spin around and so this would go a long way to help make the piston spin around in its very circular way smoothly.
 * So with this part in place, i could start putting together the various parts. I began by placing the displacer in the tin can and covering the lid. I now had to make sure it covered the tin can perfectly. To the small air spaces at the sides of the lid, i added the amount of epoxy till i was able to seal it as tightly as possible. This part has to be as airtight as possible because any air being lost is the efficiency of the engine being reduced.
 * For the power piston, since it is above the lid of the tin can, i had to make sure it was well done else it would fall off. so it had a lot of time to dry up.
 * When it came for me to attach the pistons to the crankshaft, i was initially having problems joining the wire from the crankshaft to that of the displacer. So to solve this problem, i got hold of some thin rubber material which loses its volume when heated. This turned out to help a lot as all i had to do was to place the two wires inside it and warm the sides with a lighter. This holds them both tight in place.
 * The last part of the crankshaft was the flywheel. This seems as not too important but it actually happens to be quite necessary. This is because for the engine to function, it has to be given an initial push. This push has to be sustained by a massive (not too large) material. Thus the flywheel needs to be quite heavy enough for the engine to support and turn.I made my flywheel out of normal CD's i was no longer using. I just glued three of them together. since the hole at its center is normally larger than a tiny wire, i overcame this problem by adding paper around the wire till it was large enough to fit perfectly.
 * [| engines]
 * [|wood burning engines]
 * [| air compressor]
 * [|fan engine powered]

Assign Task4

 * Once the parts dry fully, I will have to check how well it works and fix any parts that may give trouble.

Compare actual work done to Task4
Rationalize differences

Week4 Narrative
Upload photos to wikimedia. Upload video to youtube. Convert all spreadsheets, documents, and presentations to wiki format and create wiki subpage of your page for each of them. Link to them here in a narrative that tells a story. High light the problems (engineering problems) you had and how you solved them.

Week4 Peer Review
Go to each team mates weekly summary wiki page. Read their activities and narrative. Then go the associated discussion page. Say something positive on this page. Try some constructive criticism. Add your name and a signature ~ by entering four tildes in a row to create a time and date stamp. Create a new category if another team mate has already commented here.

Complete Project Page

 * [| engines]
 * [|wood burning engines]
 * [| air compressor]
 * [|fan engine powered]

Start Next Project Week0 activities
During this week you will perform the week0 activities of the next project.