Non-linear fuel pressure reg - #2

[Greg Hermann]

>> But then it occured to me, the diaphram surface area on which
>> the fuel presses against, and the surface area of the vacuum
>> side of the diaphram is equal.  So the vacuum is probably just
>> acting as a delta to the fuel pressure only, not the spring, and
>> the spring is probably just setting the base pressure.  In other
>> words, a faster rate spring will simply compress more from the
>> fuel pressure alone, then the delta created by vacuum will remain
>> the same.  So I guess there's a good chance that using a spring
>> of a different rate won't make any difference.
>
>consider the vacuum to be a 2nd spring
>the 1st spring is a constant source
>the vacuum is a variable source
>a diff rate spring will make a change in the variable generated
>the base height of the spring sets the initial pressure

But, to get a regulator that will give something approaching a constant
output pressure vs. load, you need a spring that is of a soft enough rate
to give  pretty constant force over the travel of the regulator valve. It
would be a grave mistake to try to get a rising rate out of regulator
offset!!

Regards, Greg
>
>Clive