Electronic valve control

[Shannen Durphey]

steve ravet wrote:

> Shannen Durphey wrote:
>
> >   I guess my earlier post never made it through.  One way to do this would
> > be to control the lifter bleed down rate.  If the cam had a high lift/long
> > duration lobe, then the bleed off could be held to a minimum during the
> > earliest part of the lift, and then dumped before the valve is open too long
> > to create early valve timing and lift.  As RPM increases, this could be
> > reversed.  If the lifter were made such that it had a minimum mechanical
> > lift then it would always open the valve no matter how much fluid pressure
> > there was within the lifter body.  In current engines, this could give a
> > rough form of valve control by using lifters with a fixed bleed down rate
> > and controlling the supply pressure.  Crude, but still better than fixed
> > lift and duration.
> >
> > Shannen
>
> That already exists, it's called a Rhoads lifter.  It collapses more at
> low RPM, which gives your lumpy cam a better idle.
>
> I know the electric valve topic has come up before and gotten some good
> discussion, esp from the Ford guy (Ed Hernandez??)  Haven't seen him
> post in a while, though.  One of the good ideas that came out of the
> discussion was eliminating the starter:  Computer locates a couple of
> pistons that are near the top of the power stroke.  Open the intake,
> squirt in some fuel, close the intake, apply a spark, voila the engine
> is started.
>
> --steve
>
> --
> Steve Ravet
> International Meta Systems
> http://www.imes.com
> steve at imes.com

  Well, the Rhoads lifter (and the Crane type) is a fixed bleed rate,
uncontrollable lifter.  Although it is tagged as a variable rate lifter, the
variable is only in the amount of lift and duration achieved.  Actually, worn
lifters do the same thing.  Niether one is able to change the timing, only to
"reduce" the cam lobe.

I've seen pictures of a sensor which Cadillac used on an experimental system that
used no starter.  This was back in 92 or 93.  The GM instructors told us to watch
for it in the near future. Still watching...