Chainsaw Repair

The combustion chamber question was not from a paper, just my own musing.  The more fuel/air you can trap in the combustion chamber, the more energy is stored in there at ignition.  Delivery Ratio is a way of measuring that by comparing the trapped volume to the displacement. 

So if you can increase the volume available to trap that fuel/air by increasing the combustion chamber volume, do you increase deliver ratio?  You still have to turn whatever is trapped into mechanical power effectively, so DR is not the only factor by far - and a larger combustion chamber (lower compression ratio) may really hurt in doing that.

see where you are going with this.

imo, combustion chamber size sets compression.  since compression is pressure and the higher the pressure the higher the heat, and the more heat, the more power.  so i would side, on that the smaller the chamber - the better.  because of the whole pressure cooker idea.

the heat, got me onto the whole otto cycle p-v diagram/heat transfer thing a few weeks ago.  there is a free program that looks at this.  it is what is used for both 4st and 2st.  it is way off for 2st, when i plugged in heat data numbers for a 2st, from blair's book.  he came up with a better way to look at this.  anyhow, you could plug in different values for compression ratios, and use the program to get your own conclusions.

<edit> added the link here:  http://ronney.usc.edu/spreadsheets/