atomization enhancement

[Howard Wilkinson]

Roy:
    I find that number hard to believe if my conversion figure is
correct 1 bar = 14.5 PSI (rounded).  26100 PSI........  You won't
catch me working around one of those systems... a leak could easily be
fatal!     It that the system on Caterpillar I've heard about where a
cracked line can cut put out a fuel stream that will cut steel.
    The Ford "Powerstroke" I've been told is a single rail system
which has an oil pressure driven injector which is computer triggered.
An extra oil pump supplies pressure to the injectors which use the oil
pressure to create high injection pressures.  I've never worked on the
power stroke..... only the old 6.9 & 7.2 engines which used an
ordinary rotary pump.  New injectors for the Powerstroke are $500.00
each according to the local Ford people.... I suppose $4k for a set of
injectors isn't so bad if you can afford a $40K pickup.
H.W.

-----Original Message-----
From: Roy <spectric at yahoo.com>
To: diy_efi at efi332.eng.ohio-state.edu
<diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, May 04, 1999 7:56 AM
Subject: Re: atomization enhancement


>> Hi all
>
>  The Bosch single rail system being introduced   on
>diesels uses a mechanical pump to generate a     fuel
>rail pressure of around 1800 bar.  The injectors   are
>triggered like petrol injection injectors by a
>signal from the ECU.
>
>--- Greg Hermann <bearbvd at sni.net> wrote:
>> >A "puddle" of fuel in this context can mean a cloud
>> of droplets in the port.
>> >The shock wave that hits this breaks up the drops
>> into smaller ones.  Sure
>> >it gets diluted, etc. but its the best we have for
>> now and it does work
>> >pretty well.  The only way to inject atomized fuel
>> in a short period of time
>> >is with a mechanical injection pump except maybe
>> the stuff used in single
>> >rail diesels.
>>
>> Or with an air boost.
>>
>>  Does anyone know what the single rail diesels use
>> for
>> >pressure and injectors?
>>
>> The injectors are directly above the chambers, and
>> are actuated by an extra
>> cam lobe/rocker arm. No idea what the pressure in
>> the injector itself goes
>> up to when it gets actuated--but HIGH--Probably
>> hydraulic tappet style
>> pressures. On a Cummins PT system (Pressure/Time)
>> the fuel rail pressure
>> varies with engine speed/ load, as this pressure is
>> what determines how
>> full the injectors get before getting activated by
>> the cam. Up to maybe 300
>> psi in the rail. Changing the "button" in the
>> Cummins fuel pump changes the
>> pressure /speed output curve of the pump, and thus
>> changes the amount of
>> fuel injected at full load on a Cummins. (Not all
>> Cummins B series
>> (pick-up) engines have PT injection. This is 855,
>> KT, and triple nickel
>> stuff.)
>>
>> On Jimmys, there is a rack the length of the head
>> which varies injector
>> stroke, (adjusting the lash on the injector rockers
>> and adjusting to
>> equalize the strokes of the injectors is the source
>> of the term "running
>> the rack" or "running the overhead") and the fuel
>> rail in the head is at
>> relatively constant pressure, maybe 150 psi??
>> But--again, the actual
>> injection pressure is on up there.
>>
>> Regards, Greg
>>
>>
>>
>>
>>
>
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