Throttle Plate Control

Andrew Dennison ADEN at
Mon May 15 00:13:47 GMT 1995

> From:          Craig Pugsley <c.pugsley at>
> Hi,
> I'm currently designing a rev limiter that works by cutting out the
> spark when the revs exceed a certain limit. I was thinking of
> progressively cutting out more sparks as the revs go over a certain
> level to reduce power (eg at 7000 rpm) then all the sparks (eg
> 7500 rpm) IE:
In the Bosch Automotive Electronics Handbook they talk about rev 
limiting by chopping spark, but they use a hysteresis of 80RPM ie
spark disabled at 7580, and reenabled when revs drop to 7500.  This 
way you won't skip too many sparks so you won't get a huge backfire.

I went to the 2L super touring car racing at Calder Park on Saturday 
night and you could hear when the drivers hit the rev limiters as the 
car started missing (until they remembered to change gears :) ).

I also understand that MOTEC use this 'spark dropping' technique in 
their traction control algorithms.

Andrew Dennison - Research Associate
The CIM Centre
Melbourne, AUSTRALIA
Phone: +61 3 214 8296
Fax:   +61 3 214 4949

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