At 08:44 AM 9/13/2007, tinker man wrote...

>How is engine RPM related to ignition pulse frequency?
>The motor is a 4-stroke, 4-cylinder, where every cylinder gets a spark
>once in a complete revolution and no two cylinders are sparked
>concurrently (1-4-3-2 firing sequence as per Bentley), so it seems it
>should be a 1:4 relation. Can anyone verify or correct this
>conclusion?

A 4 stroke, 4 cylinder engine will fire twice per revolution. Every
cylinder gets a spark once every 720 degrees (spark, 180o power stroke,
180o exhaust stroke, 180o intake stroke, 180o compression stroke,
repeat), so 4 sparks in 2 revolutions = 2/revolution.