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Patrick wrote:
Would this be using premixed gas & oil? If not, could there be an issue with the fuel washing the oil off the walls?
I'm using premix, but that raises another possible issue I was thinking about.
The point of direct injection and timing the spray is to keep the fuel in the center of the chamber where it would actually burn. Is there a possibility of being successful enough at keeping the fuel (which contains the oil) in the combustion chamber center that you end up starving the apex seals of lubrication?
Heading to OSH this evening!
Patrick
Lehanover@aol.com wrote:
As you said, fuel pooling is a problem even for injected engines. So you see water heated manifolds, just as in carbureted engines. Note the Lycoming with the distribution pot inside the oil pan. Heated oil keeps the mixture in a gas like state and the latent heat of evaporation helps cool the oil. On hot days there is a loss of power based on intake air temperature, but they suffer fewer carb icing events.
Injectors do a better job of cooling the intake tubes close by, and absent some warming agent, some condensation will return to the fuel.
At the least at lower power settings. So Mazda would appear to have moved the injector to the housing so that the fuel spray is facing the 300 degree plus rotor face. Plenty of heat to maintain a gas like state. So the rotor face is cooled some by the fuel. And thus a cooler oil in the rotor. There is no power loss because the chamber is closed and incoming air was not heated prior to entry so density was not lost.
Lower rotor face temps allow for more intake to enter, and thus more power.
The injector is firing into a low pressure unless turbo charging is involved. I am unable to detect a downside to this layout.
An idle at 2000 RPM can be tolerated, to protect reduction gears.
The racer idles between 2000 and 2200 RPM. So one big injector might do just fine, even if idle is less than ideal.
Lynn E. Hanover
In a message dated 7/27/2011 2:00:15 P.M. Paraguay Standard Time, echristley@nc.rr.com writes:
The MegaSquirt can time the injection based off of the ignition
timing.
I'm having some issues with my manifold. The way I built it is
causing
fuel to puddle in the bottom (so, you live, learn and rebuild). I
can
probably move the two fuel injectors to the oil injection ports
easier
than I can build a new manifold. The other two injectors are at the
stock position in the center plate. Then I would tune the fuel
injector
timing to minimize EGT.
Am I fooling myself? And, if so, how?
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