[Diy_efi] Seen one, want LOTS more !!

[Greg Hermann]

At 2:57 PM 1/10/03, Oolan Zimmer wrote:

 Garrett's new catalog,
>>http://www.turbobygarrett.com/turbobygarrett/jsp/index.jsp I'm not sure how
>>to read them, but I'm guessing Oolan's links will help.
>
>Thanks, Grant!

Got the Garrett catalogue at <www.limitengineering.com>. LOTS of good info
in it, don't forget to grab the tech section !

>
>I took the time to read the thesis I posted the link to last night, it's
>point is that turbine maps aren't as useful a design tool for automobiles
>as one would think.  The turbine maps are generated from steady-state
>conditions, while in a real engine the turbine is hit with (possibly
>supersonic) pulses from individual cylinder discharges.  This can result in
>quite different behavior than the steady state tests would imply.

This depends _very_ much on the type of exhaust manifold used !! :-)

Generally, you get better turbine efficiency with a pressure recovery type
exhaust manifold than with a pulse conversion type, but a pulse conversion
type can give much better transient response---

Greg

  He
>proposed some alternative models for understanding turbine behavior when
>attached to an internal combustion engine.
>
>As I understand it, turbines in turbojet engines see closer to steady-state
>conditions, and steam turbines in power plants see steady state
>conditions.  The turbine maps are all you need for a power plant, and a
>turbine and compressor map should be enough to design a single-stage turbojet.
>
>Oolan Zimmer
>o_zimmer at soltec.net
>
>
> > Santa wife, who is a librarian the rest of the year, managed to get me a
>> > copy of the (out of print) Humphries book "Automotive Supercharging and
>> > Turbocharging Systems" (Motorbooks)
>> >
>> > GREAT book, best one I've ever come across on the subject, including
>> > McInnes and Bell.
>> >
>> > Long story short, on page 112 (bottom left) is a TURBINE MAP, credited to
>> > Garrett and said to be for a TO-25 turbine. Essentially, it consists of
>>two
>> > graphs -- one is Turbine Pressure Ratio vs. Turbine Efficiency, the other
>> > is Turbine Pressure Ratio vs. Corrected Turbine Mass Flow (in lbs./min.).
>> > In this particular case, because the TO-25 has an integral waste gate,
>> > there are five lines on each of the two graphs--each line for different
>> > waste gate positions between 0.0" (closed) and 0.4" (wide open).
>> >
>> > The main point is that THIS DATA EXISTS--- SOMEWHERE-- and quite likely
>> > exists for every possible pairing of turbine wheel trim and exhaust
>>housing
>> > (each A/R housing and configuration--on center, tangential, or split--
>> > should have a different curve, for each and every Garrett turbo !! In the
>> > case of turbos without integral wastegates, there would only be one line
>>on
>> > each graph, BUT THAT'S ALL THAT WOULD BE NEEDED !
>> >
>> > My POINT is that THESE turbine curves are ALL of the rest (besides the
>> > compressor maps) of the info needed (only other number needed is pre
>> > turbine EGT !!) to do a full quantitative turbo match to an engine, rather
>> > than doing it "by guess and by golly" !!
>> >
>> > SO--does _ANYBODY_ know where to find copies of the rest of these turbine
>> > maps for Garrett (or any other mfgrs.) ???
>> >
>> > Thanks,
>> >
>> > Greg
>
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