KISS System

[Orin Eman]

> >     I may be stupid about electronics, but it seems to me that most of
> > the EFI systems out there are way too complex.  Anybody out there
> > building a KISS EFI system that doesn't require operator intervention?

> Yep,  been twiddling with an idea for the Bosch K-jetronic system, which
> is what you were describing.  All my system adds is an O2 sensor and a
> stepper motor that will manually controll the control pressure regulator,
> the system will run closed loop, as soon as  a temp sensor trips.  So the
> system will run normally at startup (rich), and when the enging gets up to
> temp, the O2 sensor will begin to feed signals to a box that just
> increments the stepper motor in the proper direction, affecting control
> pressure up, or down, as needed.  The main disadvantage is the system is
> constantly trying to seek out the best mix, and tends to overshoot it,
> though that is a minor control system problem.  If an O2 sensor from those
> new Toyotas was available then a perfect mix could be obtained and
> controlled within a tight ratio.

You are describing the later Bosch CIS systems, sometimes called CIS-E.
They don't have a control pressure regulator, but have an electronically
controlled differential pressure regultor attached to the fuel
distributor which has the same effect as what you are describing.

Inbetween, there was K-lambda which used a frequency valve to control
the mixture, along with an O2 sensor.

Orin.