anotomy of proportional valve

[Konstantin Bogach]

I took apart proportional valve completely.   I am sure that 1mm or even less in
normal travel length for the pin. At least, for this type of valves.
But I still don't uderstand how it works. Bernulli law does not help.  Ok... will
get it later.

Konstantin Bogach.

>
> From: "Bernard Littau" <bernardl at acumenassociates.com>
>
> I am not claiming I know how it works for sure, but my sense is that the
> proportion is mediated by the spring that attaches the lever to the
> trapezoidal arm.  The spring is an important part of the valve's function.
> As the rear wheel moves away from the car (down), spring pressure on the
> lever is increased, and proportionally less brake pressure is allowed to
> activate the rear brakes.
>
> I think the general idea is the pin is normally closed, and opens just
> enough to allow some brake fluid to pass to activate the rear brakes.  The
> 1mm of travel didn't bother me when I had mine out.
>
> It seems that the one we have is a dynamically adjusted version of what this
> guy is talking about making:
> http://members.aol.com/dvandrews/bpvalve.htm
>
> I can't figure out how our proportioning valve does what I think it is
> supposed to do :-)  I guess the thing works because the rears are on one
> "pump" and the fronts are on another "pump" in the master cylinder, and
> these proportioning valves somehow introduce a difference in volume or
> pressure between the two closed systems.
>
> Puzzled, but trying to think,
>
> Bernard Littau
> Woodinville, WA
> '88 5ktq
>