george wright wrote:

Just a comment.  About 30 years ago I bought my wife a new RX-3.  When I

was

reading the manual it stated that it would run on 60 octane!  I had a
brother in law working for customs who borrowed it and would fill it up
across the border from Pemex with stuff that might have be 10% urine by
volume.  It ran fine.  And the engine didn't seem particularly hot

running.

It did have seal issues.  What I'm wondering is if the modern high output
types might not demand very high octane fuels.  I've been told that they

use

95 octane premium in Japan.  As for the two-cycle type direct injections -
we've been researching the types used on the PWC engines.  They use very
high pressures (heat of compression issues?).  They had to go to such
systems to comply with CARB, but if you talk to people in the PWC

industry,

direct injection is seen as an interim solution and the four-strokes are
taking over.  I believe Mitsubishi has some pretty impressive automotive

DFI

systems which cannot be used in this country because of octane issues.

----- Original Message -----
From: "ACRE" <rotaryeng@earthlink.net>
Sent: Tuesday, January 04, 2005 7:24 AM
Subject: Some data from Mistral - break through data

     > Have people played with direct injection on a rotary - like many
of the
     > 2 strokes have been running?  This is pretty neat stuff...  The
fuel can
     > be squirted in right by the plug, which when done properly means
that
     > it has very little chance being wasted down in the squish areas

of

the
     > chamber - where it can't burn anyway.  It also has the potential
to make
     > manifold design easier because you don't have to worry about
making
     > sure the fuel stays with the air.
     >
     > Regards,
     >
     > Matt-

     I think some work was done but fuel vaporization left a lot to be
desired
     as I recall. Probably a little intake manifold heat would help
     the BSFC but must be turned off when max power is needed.

     Paul Lamar

Paul, you may not remember this but I mentioned that the Mercury
6 cylinder two stroke outboard injection looked perfect to use on a
rotary! They don't have mixing problems on the 2 strokes due to the
high pressure of the injected mixture atomizing it very well. It seems
like a perfect way to use the rotary combustion chamber like a

stratified

charge piston engine combustion chamber. I believe the hydrogen
powered rotary injected by the first spark plug. Less problem with
mixing of course.
Bill Jepson

I am almost certain Mazda tried all these things. There is a lot of
pressure
on them to improve the MPG. Note the intake heat on the RX8.

Paul Lamar

george wright wrote:

Just a comment.  About 30 years ago I bought my wife a new RX-3.  When I

was

reading the manual it stated that it would run on 60 octane!  I had a
brother in law working for customs who borrowed it and would fill it up
across the border from Pemex with stuff that might have be 10% urine by
volume.  It ran fine.  And the engine didn't seem particularly hot

running.

It did have seal issues.  What I'm wondering is if the modern high output
types might not demand very high octane fuels.  I've been told that they

use

95 octane premium in Japan.  As for the two-cycle type direct injections -
we've been researching the types used on the PWC engines.  They use very
high pressures (heat of compression issues?).  They had to go to such
systems to comply with CARB, but if you talk to people in the PWC

industry,

direct injection is seen as an interim solution and the four-strokes are
taking over.  I believe Mitsubishi has some pretty impressive automotive

DFI

systems which cannot be used in this country because of octane issues.

I want to make sure that everybody understands that we use a different
octane-number norm in Europe that you use in the USA.  And I believe Japan
uses yet another... although very close to the European one (can a
"Japanese" confirm or infirm this?).  Octane is measured in two different
ways (look at literature on the net for a precise (???) definition):
Research Octane Number (RON) and Motor Octane Number (MON).  RON is always
sensibly higher than MON.  In Europe, the octane number specified at the
pump is RON.  We are using 95-octane (RON) fuel for most of our tests on the
bench (we also use avgas, but sparingly given the cost of avgas in Europe!)
If my memory serves me well, octane number in the US is (RON + MON)/2.
87-octane gas is therefore the closest thing to 95-octane European petrol.
Mazda Europe recommends 90-oclane (RON) or higher on the blocks we use.
They should therefore work fine with US 83-octane.  However, an extra bit of
detonation edge on the turbo engine is not a bad thing, that's why we
recommend using higher quality gas even though it has actually a slightly
lower calorific content.

Excuse me if I spelled out the obvious.

Best regards,

Francois

 
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