Author Topic: ignition timing  (Read 2378 times)

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Offline gtpuller

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ignition timing
« on: December 23, 2010, 09:10:33 PM »
Found this on the net sorry dont remember where

An engine at 6000 RPM has 100 Trigger pulses per second so the flywheel turns 360 degrees in 1/100th of a second so to change the timing one degree we will only have to delay the trigger pulse by 1/3600th of a second. Is this math right i think it should be 1/36000th of a second ie. (.027ms)/ degree of timing at 6000RPM.

Am I missing something?


Tim Johnson

Offline sandsnipe

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Re: ignition timing
« Reply #1 on: December 24, 2010, 08:10:29 AM »
By my calculations you are right.
2.7777777777777778  -5
Jim
"Life is a work in progress!"

Offline Roger S

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Re: ignition timing
« Reply #2 on: December 24, 2010, 08:21:15 AM »
That's pretty mind boggling to think about what's going on in an engine at higher rpm. Think about the intake and exhaust pulsing through their tracts.. starting/stopping/reversion..


Offline gtpuller

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Re: ignition timing
« Reply #3 on: December 24, 2010, 08:23:14 AM »
By my calculations you are right.
2.7777777777777778  -5

Thanks
Tim Johnson
Tim Johnson

Offline Goeytex

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Re: ignition timing
« Reply #4 on: December 25, 2010, 06:03:42 PM »
time period in seconds = 60/RPM
time period in  milliseconds =  60000/RPM
time period in  microseconds = 60000/RPM * 1000

Therefore ...  time period for 1 degree (us)  = 60000/RPM * 1000 / 360

So at 6000 RPM ....   60000/6000 * 1000 / 360 = 27 microseconds

at 1000 RPM .....      60000/1000 * 1000 /360 = 166 microseconds


THis is the kind of math that is needed when using a microprocessor
that does not support decimals ( no floating point). Also no portion
of the math (as it is done in sequence} can ever exceed 65535 or go below zero
there will be an overflow.

Bill    
Bill Roth
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Austin, TX.
Email: bill.roth@comtrotech.com

Offline GRUBDIGGER

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Re: ignition timing
« Reply #5 on: December 25, 2010, 07:26:22 PM »
MY HEAD HURTS NOW. :lol:
JOHN HERRING
ARMA TECH
TRI-STATE RACING MOWER ASSC.
http://wwwtsrm.smfforfree.com/