Questions....

[R. N. Dabney]

>
>On Wed, 15 Feb 1995, Richard N Dabney wrote:
>
>> >1) What are the differences between "peak-n-hold" and
>> >saturated injectors?  Is it just the coil resistance,
>
>> The voltage it takes to pull in an injector is greater than the voltage 
>> it takes to hold it on. A higher voltage limits the on/off frequency of
>> the  injector because of the back-emf generated by the "saturated",
>
>    I was under the impression that it was current that was dealt with 
>when driving injectors.   The description of how Cherry Semi's CS-452 is 
>that "when the current reaches a pre-set level, the driver reduces 
>current by a 4:1 ratio and operates as a constant current source.  This 
>holds the injector open and reduces system power dissipation"

That's true. In order to raise the current to the pull-in level through the
fixed coil resistance, the voltage must be raised.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Richard Neill Dabney
GM/DOE Fuel Cell Project
MS J588 TA-46 Bldg 16 Rm 7
Los Alamos National Laboratory
Los Alamos, New Mexico 87545
505-667-6086, 665-6173 (fax)
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