Fwd: eddy current brake

[Mark Eidson]

The engine cranks at 100-200 RPM so it will have to run down that low to
start the engine.  The on chip PLL VCOs we use have a range of 2:1 and run
in the MHz range.  The divide down chain is programmable and would have to
be set to keep the VCO in its operational range.  This would require some
confuser intervention but this would be part of the RPM code that is
required anyway.  My idea is to have the PLL frequency generate some 2^10
pulses per cam rotation and use decoders to generate the required injector
and spark signals.  A distributor similar to the Ford signature type gives
all the information required for sequential operation.  me

At 04:51 PM 12/12/96 -0600, you wrote:
>>It's my understanding that the dynamic range, 20:1, is difficult for a
>>simple PLL.  I think the confuser would have to adjust the feedback based on
>>the current RPM range to keep it locked.  me
>>
>
>Lessee, 600 at idle to 6000 is 10:1, which is enough for me.  With a 4-star
>crank sensor, you get a pulse every 45 degrees, since 2 revs = 360, right?
>Then, if you PLL'd the freq by 45, you'd have 1 degree pulses, by 90,
>.5 degree.  Am I right?  I think I understand the need for 'reasonable'
>accuracy with firing, but you've already got a hardware (crank) 45 degree
>reference.  The PLL jitter shouldn't give but only a few tenths of a degree
>error, if that much.  Capture shouldn't be a problem, as I don't see how you
>can rev or decelerate the engine fast enough to lose lock.
>
>Remember, I'm just positing here -- never actually tried this.
>
>
>Tom Cloud <cloud at peaches.ph.utexas.edu>
>
>
>
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