Min. injector off time

[TBK]

What, exactly is the symptom in this "shutdown"? Do you mean current
protection?

TK
-----Original Message-----
From: Scott Shotton <stucky at interaccess.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, February 03, 1998 7:39 PM
Subject: Re: Min. injector off time


>bruce plecan wrote:
>>
>> Please someone help me on this.
>> "They" say not to run the injectors over 85% PWM,
>> on time.  OK, from what I've read the lag time from
>> V on till injector open can range from .0012 sec
>> Peak+Hold to .0018 sec for Saturated.  Right?
>> But when they say 85% if the injector was on for
>> 85 days, and off for 15, then that would be a 85%
>> on time, but the injector might be crispy by then.
>> So what is a min. off time that would allow an
>> injector to "relax"+"cool-off" enough??..
>>   If there is this .0018 reaction time, would then
>> a .002 sec. be considered a min. off time?????..
>> If not what would be????.
>>   Would be above be a new consideration for
>> a high rpm motor for injector sizing????...
>>   TIA  Bruce
>
>
>This probably doesn't answer your question, but:  the injector probably
>wouldn't have a problem if it were on 100% of the time.  If I am not
>mistaken, and I could be wrong, the off time allows the driver to cool.
>I know an injector, or bank of injectors, with a low resistance flows
>more current and can destroy a driver(s).  I have seen it many a time on
>GM 2.8/3.1's.  The plennum design holds heat in and "bakes" the
>injectors.  Injector resistance drops.  Drivers shut down.  I see about
>8-10 of these engines a year with this problem.
>
>If anyone knows different, please let me know.
>
>Scott
>