Piston trip igniters

[Barnbikes]

Has anybody built a model engine with piston trip igniter?

Was looking at an old Patent drawing and the engine had this on it. I understand the concept of less moving parts but it puts ignition after TDC. Can't believe the engine would run very well.

 

[Ogaryd]

I believe Henry Fords original quadricycle used the piston trip igniter, it seemed to run OK, I've not seen this used in a model but would be interesting to try.

 

[idahoan]

My Pacific engine uses a piston trip ignitor.
http://www.homemodelenginemachinist.com/showthread.php?t=17832

Sadly I haven't finished it yet; but I know that it will run on the ignitor because my buddy built one and it runs real nice!

Dave

 

[Barnbikes]

Not very good picture but here is the patent.

 

[kadora]

Good idea
How it works ? In cylinder electrode in contact with piston serves as switch for ignition coil
or between electrode and piston jump sparks from ignition coil?

 

[Charles Lamont]

I understand the concept of less moving parts but it puts ignition after TDC.

Are you sure?

 

[Barnbikes]

Are you sure?

Spark would happen when points broke open. Which would be after TDC.

 

[idahoan]

What if the points were normally closed and the piston opened them? A switch (spark saver) located somewhere on the engines linkage would only allow current to flow just before the points opened; thus saving the battery and coil?

Just some thoughts.
Dave

 

[Barnbikes]

In the drawing the pin on top of the piston is half of the point set.

 

[idahoan]

That would complicate things; I guess I was thinking of a two point system.

Dave