You are correct. Typical vehicle fuel pumps can't respond that fast.
You might need to consult with a mechanical engineer to verify the details, but there are some types of valves where a small 'pilot valve' is controlled by a solenoid (voice coil). This in turn controls the flow/pressure in a main line via 'hydraulics' where the hydraulic working fluid is simply a small amount of the fluid being controlled tapped off the supply line.
-- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ Madness takes its toll. Please have exact change.
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Wait a second here.....i'm not so sure I dont need 30 lbs of force if i want to regulate 30 psi, for instance...the fluid being regulated has to "lift up" the ball in the orifice, and if there is 30 lbs on that ball you get 30 psi, yes?
I took apart the fuel pressure regulator that I will be modifying with the linear force actuator. Its got a 3/4" diameter spring that I could see easily taking 50 lbs of force to get it to the compressed length that it was before i sawed open the regulator... (the stock pressure is 50psi)
it still remains for me to put the opened up regulator on the car and see if i can modulate the fuel pressure with a much smaller force..but something tells me no since that same place I will be putting pressure to modulate the pressure is where that hefty spring was..
30 psi does not mean 30 pounds of force, it means 30 pounds per square inch. What's the cross sectional area of the ball? How about the orifice in which it sits?
I think the voice coil is EXACTLY what I am looking for. BEI here in san diego wants $1000+ for one that can generate about 30 lbs of force.
Rolling my own sounds good. Any idea where I can find info on making my own?
You keep forgetting that your orifice size is NOT 1 SQ.IN. !!
...Jim Thompson
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| James E.Thompson, P.E. | mens |
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America: Land of the Free, Because of the Brave
If you can buy one off the shelf that meets ALL of your needs, and has good docs, and if the point of this exercise is to get something working now, then buy it and be done with it.
You'd never be able to design/build an equivalent from scratch that cheap, and the other alternatives seem to be basically "If this is a hobby project, and your time doesn't cost anything..." ;-)
Good Luck! Rich
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OKAY...i'm not forgetting that the orifice is not 1 square inch. I understand what y'all are saying about 30 lbs not being neccessary to regulate 30psi in a small orifice.
I took the regulator apart and pumped air through it with a small air pump i have. It took both of my thumbs pushing as hard as I could on the diaphragm to get up to 25 psi...however the pump i was using probably couldnt pump more air than that anyways...
I suppose I will have to try it on the car with the stronger fuel pump..
The spring that came out is HEFTY. Hefty enough to where I could not compress it to its compressed (pre sawing open the regulator) length with my hands! I would not at all be surprised if it took 50+ lbs of force to compress it to fit back in the regulator, which is what is leading me to believe that 50 psi takes 50 lbs of pressure.
Are you understanding why I am being misled, apparently?
If the spring I took out was wimpy that would be consistent with the small orifice/less force required idea.
Still gotta test it...
If the "pressure regulator" is actually a simple relief valve which returns excess to the tank then the orifice size matters, but not in a normal pressure regulator where spring (or other) force balances outlet pressure on the opposite side of a diaphragm, so it is diaphragm area that matters most, with orifice area having a relatively small effect, which is good since the orifice area causes outlet pressure to vary with inlet pressure. "PSRR" ~ diaphragm area/orifice area.
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