I'm attempting to make an experimental horizontal, gear-less, 4-stroke engine of my own 'design' (a euphemism for many excess tapped holes where yet another daft idea didn't work.) The ignition cam is directly on the crankshaft, there being no half-speed shaft, so clobbers the 'points' every revolution. The wasted-spark principle, see later.
From an idea by Jan Ridders, I've used a standard microswitch for points, connected to a 'Pegasus'-brand electronic ignition, which I bought from Hobby King in Singapore. The original Hall-effect sensor was lost some time ago!
My problem is that there is a spark on points opening, and another on points closing (about sixty-degrees later) so I'm actually getting 4-sparks per revolution: one at firing point; another during the power-stroke, which is only trying to re-ignite what's already burning; the third spark is at the end of exhaust but the fourth one is during inlet/suction, and I feel this is giving a problem.
Presumably, even with a Hall-effect sensor, there would be two-sparks because the sense wire has to go high- and then low-voltage at some point?
Question: is there any way to suppress the second spark of each pair? (I can live with the wasted-spark at the end of exhaust.)
Geoff,
Thailand.