Re: [alfa] Diesels and dollars

[webb.p@xxxxxxxxxxx]

> Nonsense, Peter---in fact, get a clue !!

When you've built and installed your own home grown injection system as I have, you can make that statement.   See below as to why you should read what's being said before you jump to an incorrect conclusion.

> In an efi spark engine, the fuel is injected and evaporated long before it
> is lit, the duty cycle and/or injection rate of the injectors has NOTHING
> to do with the burn rate, as it most certainly DOES in a diesel. Even in a
> direct injection spark engine, the fuel is injected during the compression
> stroke, LONG before it is lit.

Noone said it had anything to do with it.   The statement was the higher the pressure the faster the fuel is delivered.   For EFI, that is a pattently false statement for several reasons.   First, on an electronic injector the fuel pressure works against the pintle increasing the opening time and decreasing the delivery, or injector opening time.    The pressure in the manifold (port) or cylinder (direct) offsets the rail pressure.   This is why the rising rate pressure regulators are used in forced induction.   The rail pressure is referenced against the manifold pressure to offset the fuel pressure against it so the fuel can flow at a constant rate.   This is further complicated by the injector coil opening the pintle against the rail pressure.   For low-z peak and hold injectors, the pulse width modulation of the injector coil decreases the flow as the PWM % can be a maximum of 80-85% before you burn out the injector or stick it open on the field coil.

> As for electronically controlled injectors in diesels (most notably the IHC
> developed Power Stroke stuff), the actual injection rate IS faster than
> with mechanical injection--because of higher pressure--which is NOT
> generated by the electronics, but by mechanical/hydraulic pressure
> multiplication tricks.

There are factors present in electronic injector field coils that make that false too.   Mechanical injectors such as the Spica or CIS operate soley on fuel pressure.   Electronic injectors operate soley on magetism AGAINST the fuel pressure.   The only thing they have in common is the pressure against which the actual injected fuel operates.  I.E  the manifold or cylinder pressure.   And again, see the statement about PWM limits for low impedance injectors.

Why do people on this digest rush to conclusions without regard for what's being stated and the experience behind it.

Sheesh

-Peter




> 
> 
> 
> Greg
> >
> >-Peter
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