EFI for Bosch mech. injection

[Frank Mallory]

 d> * From: ricrain at airmail.net (Ric Rainbolt)
>Does anybody have any info on adapting the late-'60s Bosch mechanical 
>injection
>to EFI? I understand it has been done in Germany.
>
 d>I understand that the later Bosch mechanical systems had closed loop
 d>operation utilizing an O2 sensor and a "fuel frequency" valve.  This 
 d>valves
 d>duty cycle was varied by an analog circuit to achieve the desired 
 d>level of
 d>enrichment.  At some throttle level, the closed loop is defeated and 
 d>the
 d>system returns to the preset levels prescibed by the air mass plate.

I think maybe you have the later Bosch CIS system in mind. Bosch started off
with a mechanical gas FI in 1954 (used on the Mercedes 300SL); then they went
to the D-Jetronic system with "brain box" in 1971; then to the mechanical CIS
system; finally to CIS with closed-loop control. There is no air mass plate on
the early mechanical systems.

When applying closed-loop control to the earlier mechanical systems, I believe
that control is effectuated via the barometric compensator, which can be used
to vary the position of the control rack in the pump and thus vary the amount
injected.