[OT]Electronic Cams? EDN article Link

[Bernd Felsche]

jyancey at twrol.com tapped away at the keyboard with:

> On Wed, 24 Jan 2001, steve ravet wrote:
> > jyancey at twrol.com wrote:
> > > I've read about these myself... I don't know about the starter
> > > eliminatio... you still have to get the motor spinning
> > > (somehow), can you eliborate on this?

> > open valve, squirt fuel, close valve, send spark, motor is now
> > spinning.  The valve(s) to open is based on the position the motor
> > stopped in previously...

> I suppose that could be possible... but ambient air pressures will still
> make that difficult, I would imagine. But there would be no nessisary
> order, except the valve should be closed with you fire...

As long as the corresponding conrod big-end is on the correct side,
you will get combustion is you have an appropriate AFR. It's not
going to be efficient.

> But then again, depending on the motor.I couldn't see it working on
> anything except 1-2 cylinder motors. No compression (yet), ambient
> cylinder pressures... it'll be a long cold morning before it
> starts... Not to mention the lack of combustion when you simply
> "pour" it in..

It's a brief squirt corresponding to a rich mixture for the volume
of air in the cylinder. Crank position has to be known. Engines with
1, 2 or 4 cylinders may get "unlucky" and stop with cylinders
exactly at TDC/BDC or with crank throw on the wrong side.

Even with the throw on the wrong side, one "bang" would be enough to
throw it over prior to a subsequent reversal. Valves on unpowered
cylinders can be held open (where physically possible) to avoid
compression losses.

Judging from the current SAE literature, it looks like it's more
likely that a starter-alternator incorporated into the flywheel
will be favoured for starting. The advantages of this are
significant; the starter-alternator can be used to drive the car (VW
had a test vehicle running around Europe during the late 80's and
early 90's with a similar, though more complex drive concept).

At the very least; the starter-alternator can he used to minimise
flywheel mass if "super-caps" are switched to achieve low-speed
torque smoothing by presenting a suitable "inertia".

-- 
/"\  Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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