[Diy_efi] CIS EFI via Fuel Pump PWM

[Bernd Felsche]

steve ravet tapped away at the keyboard with:
> Bernd Felsche wrote:
> > ARKK tapped away at the keyboard with:
> > > The idea was that CIS injectors could adequately be controlled via
> > > fuel pump modulation for pressure control.
> > 
> > Unlikely to be successful unless the pump is quite close to the
> > injector. System delays will be the source of control problems;
> > it'll take a while for the pressure to build up over a couple of
> > metres of fuel line.
> 
> Why would it take any significant time?  The fuel isn't compressible,

If fluid isn't compressible, how does it transmit sound? :-)
Yes, fuel *is* compressible.

The longer the fuel line, the longer the propagation delay.

> and steel fuel lines don't stretch.

Oh, they do. Any pressure vessel expands when the content is under
pressure.

It's also not unusual to have *plastic* fuel lines on road cars.
These are less susceptible to breaking when hit by rocks, etc. but
expand even more under pressure.

One of the reasons for Bosch putting the K-Jetronic
metering head close to the engine, and attached with reinforced,
braided lines, was to improve the system response.

-- 
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