Jinx099

Not sure when I thought of this, but how exactly does the rotary engine keep it's compression when the apex seals move over the spark plug gaps?

rxtasy3

iTrader: (2)

same as a pist on engine does, the plug acts as a plug in the hole.

Jinx099

but the plugs are not completely flush with the rotor housing.

Railgun

So you loose what, about 3cc of volume if not less? It's not that big of a hole thus it's not a concern where compression is concerned.

Jinx099

but if the apex seal stops (or just goes slow) in the middle of this gap, it will lose all it's compression to the other side of the seal. I'm assuming this is less of an issue with higher RPMs then?

rototiller1

You should think that thru again

Jinx099

maybe it would help me if someone posted a pic of a bare housing with a plug in it.

mgoddard1

The spark plug is much wider than the apex seal so if the seal stops over the plug you can lose compression. However, the period when the seal is over the plugs is probably less than a millisecond so there is virtually no time to lose compression through a very small gap.

Jinx099

Thanks for the explanation.

rototiller1

The seal does not simply rotate past the plugs. Its a eliptical rotation. Up and Down while going round and round. Also the volume of the spark plug holes is there during the intake cycle, so volume is not lost on the compression cycle

http://travel.howstuffworks.com/rotary-engine.htm

MikeC

This is a good question. The answer is yes, some compression will be lost but you have to look at the point the rotor is at when the apex seal passes over the spark plug. When it passes over the leading plug pressure on either side of the seal will be low, but when it passes over the trailing the pressure will be high. This is why the trailing plug has a much smaller hole.

MikeC

oops, triple post, server ain't working too well today, it gave me three errors in a row but posted the message each time.

MikeC

oops, multipost....