Mark deHaas writes:
> The subject of electronic ignitions has come up and this has started
> me thinking about building a system for my TR-6.
> If one wanted to find the best place to mount an engine position/speed
> sensor it would be under the distributor cap.
Well, I disagree. The distributor shaft is driven through a gear that
introduces uncertainty between distributor shaft angle and crank angle.
This uncertainty would not be introduced by a sensor attached directly
to the crank.
> In fact I would throw
> out the rotor and distributor cap altogether. A relatively simple
> circuit could fire those new mini-coils one for each plug. At the
> last New York auto show I was checking out the Saturn engine and they
> have two coils which fire the plugs and no noticable distributor
> cap. I guess one coil fires two plugs which are apporximately 180
> degrees out of phase of each other.
Yup. The two-coil distributorless ignition fires through two plugs
at once through each of two coils. The trick is, the "other" cylinder
is empty and the spark fires at a very low voltage. Thus most of the
coil voltage is available for the cylinder with the charge in it.
> At any rate trying to mount a relatively sensative optical or
> mechanical rotary position sensor next to a hot, vibrating , oil
> leaking engine is a tough job.
We certainly agree on this!
> The sensor would have to meet
> mil type specs for temperature and shock. If I ever build it
> I'll let the net know if it worked or not.
>
> Mark deHaas.
> DEHAASM@NAPC-1.NAVY.MIL
>
>
Regards,
Tim
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