Andrew Cunningham wrote:
Dave,
I was looking for the rate of increase during the run not just the end
points. Within a typical (current config no WI) 0-100mph run how many
seconds does it take to get to 900, 1000, 1100, 1200 ack 1300?
The other thing that I was wondering was how long (seconds/minutes?)
would you be confortable running at 1200F? If you could run WOT for a
minute, what would you consider your max temp?
The reason why I am asking is I am designing a boost controller with
an EGT Type-K feedback. This would allow more useable boost (maybe
16psi+) earlier when the engine is cooler and slowly reduce (down to
maybe 10-11 as needed) the boost to prevent EGTs from going too high.
You keep the pedal to the metal, as temps increase the boost drops
which also reduces exhaust back pressure. I have a few complete
designs that I am considering.
I am at the beginning design stage of an injection pump controller
that adjusts the pressure signal to the ALDA. The basic concept is to
adjust the fuel delivery based on the intake temperature and pressure.
I don't have all the pieces or figured out how it will all connect
yet, but I am learning how to program a microcontroller to handle the
adjustment.
Charge density should be proportional to the absolute pressure /
absolute temperature. Typical charge density is around 0.05 psia / K
with no turbo and maybe up to 0.10 psia / K with an intercooler.
NOTE: the EGR must be disabled for this to calculation to determine
how much air you have to burn.
At a given charge density, there should be an ALDA pressure that
corresponds to a near perfect match for the fuel. This way, when you
floor it you will have exactly the fuel you can use based on how much
air you have to burn. The trick will be to use a 10 point calibration
curve from no turbo all the way up to full boost.
One thing that I haven't confirmed yet is:
On a given 617 injection pump, the pump squirt/rev is independant on
the actual rpm. i.e. if the throttle position and ALDA pressure is
the same at 1000 rpm as 4000 rpm, will each rev of the engine will
inject the same amount of fuel?
Anyone know if that is the case?
I suggest it's time to study Bosch's "Diesel Fuel Injection". The 1st
edition ('94) is ISBN 1-56091-542-0 and is published by SAE. Not sure if
they've updated it (to cover the latest systems), but there's plenty of
information there.
Marshall
--
Marshall Booth (who doesn't respond to unsigned questions)
"der Dieseling Doktor" [EMAIL PROTECTED]
'87 300TD 181Kmi,'87 190D 2.5 199Kmi, '84 190D 2.2 227Kmi, '85 190D 2.0
159Kmi, '87 190D 2.5 turbo 234kmi
Diesel Technical Advisor MBCA, member GWSection
http://www.dhc.net/~pmhack/mercedes/mbooth1.htm
