Injector Duty Monitor

[Walter Sherwin]

Ummm....................here's more fuel for the duty cycle fire.  DUTY
CYCLE, by definition, is the ratio of the ON time of an injector versus the
ULTIMATE time that it could be turned on per period.  This will vary
according to the fueling "mode" that the software engineer or OEM has chosen
(ie:  batch SSDF, batch SSSF, alternating TBI, single TBI, sequential,
phased sequential).

If you are worried about dynamic injector performance (as you should be)
then you have to consider the magnitude of the ON time versus the ULTIMATE
time available for injection.  This is why an oscilloscope is so invaluable
in determining injector "headroom", and why many duty meters are somewhat
meaningless, UNLESS you know the exact firing schedule of your system.
Beware,  a software package may flip modes based on preset operating
criteria!


Take Care;
Walt.



-----Original Message-----
From: Stuart Bunning <stuart at kenelec.com.au>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Wednesday, January 06, 1999 5:10 PM
Subject: RE: Injector Duty Monitor


>
>IF YOU KNOW THE RPM AND DUTY CYCLE YOU CAN CALCULATE THE mS on time.
>for example 3% duty cycle at idle 700RPM would be 700 RPM/60 = 11.666
>REv's/second or Hz = 85.7ms and 3% of 85.7ms is 2.57 ms...
>
>
>
>
>At 12:07 PM 4/1/99 +0200, you wrote:
>>Hi
>>Just a correction, the dutycycle of the injectors does not realy mean
>>anything,
>>it is the open time that is normally of interest. The dutycycle however
can
>>give
>>you an indication of feul-economy.
>>
>>Cheers
>>Carlo Putter
>>South Africa
>>
>
>
>Best Regards,
>
>STUART BUNNING
>SALES ENGINEER
>KENELEC PTY LTD
>
>23-25 REDLAND DRIVE
>MITCHAM VICTORIA 3132
>AUSTRALIA
>
>PHONE:  61 3 9873 1022
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>EMAIL:  stuart at kenelec.com.au
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>