Rev limiting

Tue May 16 14:28:56 GMT 1995

Craig Pugsley asks:

"I'll re-ask the question, Is having sparks cut out 'randomly' likely to
be capable of causing mechanical damage to the engine, especially when
it's happening at/near maximum power RPM range?"

If you are microprocessor controlled you have a lot more flexibility.  I would
use a step by step approach.

First, as you approach red line, I would retard the spark.  You probably don't
want to retard more than say 10 BTDC.  If RPM goes past a second limit, you
should probably start firing every other cylinder.  Finally, past another
higher limit, turn of spark entirely.

Each of these three point should have a hysteresis of at least 100 RPM.


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