Subject: Rotary timeing
From: ACRE NL
Date: 6/26/2002, 4:43 PM


Royce Wise wrote:

Paul, Tracy, Ed, anyone.
How does the rotary ignition timing compare to a piston engine?
Does it fire like a 3  cylinder, 4 cylinder, 6 , or 8, or none of the
above.
Royce


Once per rev for a one rotor and twice per rev for a two rotor
180 degrees apart. It is quite practical to do away with the
crank angle sensor and trigger off the flywheel.
No shafts or bevel gears required. With a four cycle piston engine
you need to know what stroke it is on (compression or exhaust).
You need to look at the 1/2 speed camshaft to figure it out.

Tracy fires both plugs at the same time and 22 BTDC as I recall.
The Stock Mazda computer fires them at different times to minimize
emissions.

Paul Lamar


The [stock] leading spark system provides a spark to both rotors at the same time.
A spark is provided for each rotor face (3), so when one rotor has completed
its revolution it will have fired three times or once per eccentric shaft
rev.  With two rotors this makes its twice per eccentric shaft rev as Paul
indicated.

The leading spark catches one rotor in the right position for the
power/combustion stroke and the other is a "waste spark" that catches the
second rotor during its exhaust cycle (so has no effect - a wasted spark).

The [stock] trailing spark plug is slightly more complicated as it can not use the
"Waste Spark" approach of the leading igntion module and basically has a
separate coil for each rotor.

Ed Anderson

 
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