2017.02.26
Hello Paul,
this is an answer to Jose Gros-Aymerich, Madrid.
Hello Jose,
at first - please don't think, that I'm an expert. You can be shure,
that
I'm no expert at all ;-)
I've never worked at a test bed + I have never developed something
... ;-)
I just like to read + I like the shape + the moving style of the RE
... ;-)
Now let's have one more look at the glow plug theme ...
Usually you cannot "hide" the hot glow plug, until you want to start
the
combustion, say at 25 ... 10 deg bTC.
Perhaps you can invent a device to do that ... ;-)
Combustion will begin, as soon as the mixture reaches the hot plug.
So - if you take the KC 27 (of the Hercules W2000), the fuel will
get in
contact with the plug tip at araound 120 deg. bTC ! That's really
much too
early, even for slow burning methanol ...
The leading spark plug position in a Mazda rotary may be reached at
perhaps
90 deg bTC - again much too early ...
With the "far leading" position of the glow plug in one of the
patents by
Toyota, I guess, combustion will start at may be 50 deg bTC. If you
have a
lot of EGR + a "slow burn" because of the absence of turbulence + a
very
small amount of fuel (idle) in the chamber - perhaps it will work
...
But that position is in an area of high pressure difference between
two
chambers - there will be blowby from the trailing chamber
(combustion phase
- high pressure) to the leading one (exhaust phase - low pressure)
...
Enclosed is a patent by GM. Fig. 4 shows the pressure differences
along the
trochoid ...
With an ignition system, standard or Paul's type, you can define
exactly,
when the combustion shall start - typically not much earlier than ~
20 deg
bTC.
Please, don't forget, that it's not a good idea to burn most of the
mixture
before TC ... ;-)
If you have an engine "laying around" + put a protractor on the
shaft, you
can easily see by yourself, when the leading edge will pass your
opening for
a plug + a glow plug will "start to work unalterable" ...
Carburetors ...
Hm, I don't no your goals / targets. If you have a test bed with
exhaust gas
analyzer, you can do some serious work. Otherwise it's like guessing
around
+ a lot of trial + error ... (?)
If you have a W2000 motorbike + it tends to "shake" / "jerk" on
coastdown -
may be the� "pressured" actuator / controller for the little bypass
is
faulty ... ?
I have looked at my (old) papers + here's something I've found ...
1st W2000 version (sprayed in red + silver) was equipped with your
Bing
variable choke type 64/32/17
main nozzle > 155
nozzle for idle > 55
nozzle for needle > 2,76
needle No 1 in position 2
I think, the men at F+S / Hercules have spent a lot of hours to find
these
adjustments ... + as far as I know, it was working even on full
throttle ...
Of course, there's a lot to play with - needle position, nozzles,
float
weight, spring in the carb piston ...
If you want to modify something, perhaps because of another airbox,
please
change only 1 part / adjustment at a time. So you can recognize the
reason
of any difference. I know, that's pretty time consuming ...
A short list of some other carburetors for the 300 cc F+S engine
type, that
were used ...
> early aero engines (Norton / Alvis / UEL)
�> Amal variable choke
�> Mikuni or Tillotson diaphragm type
> Norton motorbike
�> SU H1F4 38 mm (mixture insert 26 mm)
�> Mikuni BDS downdraft 34 mm (but no chance to pass the emission
tests)
�> for racing > Amal Smoothbore with 34 or 36 mm diameter
The newest info comes from Aixro in Aachen (Germany) ...
�> XR 50 engine > Dell'Orto VHSH 30 CS or own YSN PWK 30
�> XF 40 engine > Bing 84
If you need more useful informations, you can get in contact with
Aixro -
they have engine test beds + all the stuff for serious measurements
...
I think, it would be good to look for a cheap injection system, e.g.
at
www.rotaryeng.net/fuel-injection.html ...
Coming now to the end - the OMC engine ...
Perhaps the NASA paper TM-89833 is the one you're looking for ... ?
Sorry, that I can't help you with the carb of Citroen ...
A "Salut" to Madrid :-)
With kindest regards
Franky / Frank Herfert
Mazda used the upper spark plug on the Le Mans winning 4 rotor
several points lower fuel burn.
Paul Lamar
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