[Diy_efi] Continuous VVT system

[Alexei Pavlov]

> > An additional ECU that controls VVT will contain
> > maps with cam shifts as function of load and RPM.
> 
> That would make good sense.  I suspect the controller
> used will need modification, if not replacement.

No except ignition, as it's a MAF/RPM system.

> 
> > I'm planning to use electro-magnetic sensors to get
> > the current angular position of camshafts collected
> > on the cams.
> 
> You may find a Hall-effect sensor to be a more robust
> sensor for that application.  A differential sensor
> based on the Hall effect would give you more angular
> rotational information, and they are becoming more
> commonplace in the automotive world now.

The problem is to mount the magnet on the camshaft. I'm afraid
if I do that steel pieces will stay on cams and destroy the
cam/tappet surfaces, while without magnets they are washed by
the oil.

> 
> An infintely-variable system doesn't seem trivial to
> me at all.  I think you may be in for some real
> mechanical engineering challenges.

Mechanically it's not complexe, you just have to control the oil
pressure in the VVT device. And it's already possible with the
original Alfa Romeo system.

The mapping is another piece of cake. I'll have to do many runs
with different timings to choose the best one for each load/RPM
pair.
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