D disease

[Dirk Wright]

On Tue, 24 Sep 1996, Johan Rodling wrote:

> 
> AS far as I know the D-Jetronic is an analog MAP system built on
transistors. Got one my self. It's primarly designed for 4- & 6-
cylinders, but is also used on V12's with a booster amplifier for the
injetors. It works in batch mode, so it fires a group three injectors
three times (?) each cycle. 

I've got a bunch of patents on the D-Jet system. It's comprised of a 
bistable multivibrator, triggered by the extra distributor points, which 
then triggers a mono-stable multivibrator with variable pulse length. 
Pulse length is responisve to temperature, manifold vacuum, throttle 
position, and speed. The bistable multivibrator determines the start of 
each pulse, the mono-stable multivibrator determines the length of the 
pulse. The output of the bistable multivibrator and the monostable 
multivibrator are fed to a pair of AND gates, which in turn drive a pair 
of power transistors that turn the injectors on and off. For 
four-cylinder cars, injectors are fired in pairs once every other 
revolution, so that one of the pairs is fired early and the other is 
fired right on time. The result is that the ones that are fired early 
don't make as much power, especially at low revs, because the fuel is 
less well atomized. At high revs, it doens't make much difference, since 
the fuel only sits for a very short time on the early cylinders.

Hope this helps.
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Dirk Wright 					            wright at uspto.gov
"I speak for myself and not my employer."               1974 Porsche 914 2.0
"A real hifi glows in the dark and has horns."            1965 Goodman House
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