Engineering Projects/Engines/Howard Community College/fall2011/550 QSM

wikipage for new engine team of 2

Problem Statement

Can you make a running Stirling engine out of house hold materials?

Team Members

Summary

We set out to construct a working stirling engine out of basically tin can. this was to be done as an engineering project over the period of four weeks for design and its building.We basically began learning learning more about the engine as time went on by consulting with our professor and online. some tips like making the displacer to be equal to half of the volume of the tin can came along the way when we had already begun so we had to make augmentations . in this case we had to fix this by adding styrofoam to the already made displacer which later turned out to work just fine. The crankshaft we made out of copper jewelery wires. these were easy to bend into shape even though a little difficult to keep that way as they were a little too flexible.

Poster

sterling engine design from tin can

full engine design

stirling engine design

design showing white displacer and power piston

flywheel attached to crankshaft

interior view of tin can

tin can diagram

cross section of the entire stirling engine

holes for diplacement of displacer due to air movement

Story

Problems we encountered while working:

Poor displacer. The displacer's problem was that it wasn't close to half the volume of the piston. It needs to be able to move a larger volume of air.
Lack of precision. The displacer rod hole through the piston lid allowed the air pressure to escape.
Crank shaft is too big. The crank itself needs to be a 1/4 the height of the cylinder so the displacer makes a full motion

Solutions we tried out:

Add a piece of Styrofoam to the old displacer so that it is closer to half the volume of the displacer.
Add a sleeve of something to reduce the volume of the displacer rod hole.
Wait to make the crank until the majority of the cylinder is completed so that the crank reaches a full range of motion.

We worked on fixing the the displacer and the displacer rod hole. To increase the volume of the displacer we took a large chunk of Styrofoam and pushed it down till touched the soda can. We then took a marker and traced around the can. Because We wanted the Styrofoam to just fit inside the edge of the beer can we knew we had to remove all parts of Styrofoam that had marker on them. To evenly cut the Styrofoam we used the hot wire device and rotated the block about its center point. After shaving off all parts with marker on them the block of Styrofoam slid just inside the can. Once the block was in the can we set it next to the cylinder and cut it close to half the height of the cylinder.Through our various documentation, we were also able to make singular advancements and ideas towards working on the project. The problem above is a good example of the problem which quite held us back a bit.It also came after our initial design in which there was not enough air between the displacer and the tin can walls. It was only after Mr Foerster's advice that we discovered that air needed to flow between its walls for the engine to function. The displacer also has to he close to half of the tin ccan's internal volume.

Decision List

List all formal decisions made with links to their documentation such as a decision tree or decision matrix.

Material List

Needed	Helpful
10.5 oz Tin can (preferably small soup can)	Hair dryer
Tall 12 oz beer can (Keystone or Coors)	Fine metal file
Metal cutters	plexiglass
2 pairs of needle nose pliers
Fast setting epoxy (rated to withstand at least 300°)
Coat hangers or 16 gauge jewelry wire
Metal/PVC piping (No bigger than .5' in diameter)
1 CD
Exacto knife
Hot glue
Heat shrink plastic
pennies
Wax paper

Software List

GOOGLE SKETCH UP Solid works

Time

Four weeks approximately 5 hours per week plus some individual work done on the side depending on the intensity.

Tutorials

Most projects consist of making instructions to jump start the next team, shrink the learning of tools and software to the minimum, advice on where to purchase materials, how to assemble, etc. Tutorials modified or created are described here with links.

Step by step instructions can be found here.

Next Steps

find a tin can with a smooth interior for the engine.
friction must be the enemy at all times.
use the lightest materials possible.
the crankshaft needs to be smooth as well. when the displacer rod is down, the power piston has to be almost fully up.
Build a working running model.
Make an instructional, time-laps video of an engine being constructed.