5000rpm rev?
#26
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I have to disagree with this point Shell. If the engine's temp is higher than gas's flashpoint, then it would be flashing over when it enters under normal operating conditions, which is hardly what we what, and we know that doesn't happen.
#27
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Yeah, that part came out all wrong. We wouldn't need spark plugs if that was case. Would the engine temperature effect the rate of evaporation?
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yup... boiling point certainly would come into play here. A hot engine will definitely increase the rate of evaporation.
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yup... boiling point certainly would come into play here. A hot engine will definitely increase the rate of evaporation.
Last edited by ShellDude; 01-27-2013 at 04:54 PM. Reason: added boiling point info
#29
Rotary Evolution
with that mindset, still more fuel would wash into the engine during run down.
easy translation, 3000RPMs = 3000 revolutions to eject vapors and unspent fuel from the engine. 800RPMs = 800(truth being the rotors only are turning at 1/3 that rate. 1000 full rotor rotations at 3k versus 267 rotations at 800rpms) revolutions to eject near the same amount in the intake manifold after injectors are shut off. there may be a few cycles where the fuel is injected that doesn't reach the plugs before they have already shut down.
a full up to temp engine will vaporize the fuel from the rotor housings and iron walls, a cool engine will have a film of fuel on the internals because the engine isn't hot enough to vaporize it before it sticks.
equivalent would be snow hitting the ground when the ambient temp is 40F, it may touch ground but it will soon vaporize. this is how i see a hot engine reacting where a cold engine would be snow hitting the ground in sub 32F climate and staying put until the snow plow comes and sweeps it off, leaving ice. friction may melt some of that ice or at least push it out of the way.
but you're beginning to see why this debate really has no concrete proof either way.
easy translation, 3000RPMs = 3000 revolutions to eject vapors and unspent fuel from the engine. 800RPMs = 800(truth being the rotors only are turning at 1/3 that rate. 1000 full rotor rotations at 3k versus 267 rotations at 800rpms) revolutions to eject near the same amount in the intake manifold after injectors are shut off. there may be a few cycles where the fuel is injected that doesn't reach the plugs before they have already shut down.
a full up to temp engine will vaporize the fuel from the rotor housings and iron walls, a cool engine will have a film of fuel on the internals because the engine isn't hot enough to vaporize it before it sticks.
equivalent would be snow hitting the ground when the ambient temp is 40F, it may touch ground but it will soon vaporize. this is how i see a hot engine reacting where a cold engine would be snow hitting the ground in sub 32F climate and staying put until the snow plow comes and sweeps it off, leaving ice. friction may melt some of that ice or at least push it out of the way.
but you're beginning to see why this debate really has no concrete proof either way.
Last edited by Karack; 01-27-2013 at 05:07 PM.
#30
weeeeeeeeee
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nah, I just floundered on flash vs boiling point lol.
You're thinking linearly. There is a rate of decay with the engine spooling down. I do agree that some percentage of fuel will definitely be expelled during spool down.
Whether that percentage is significant remains to be seen.
I like Brett's approach because by holding down the gas pedal on startup you're cutting fuel and allowing any unspent fuel in the chambers to ejected prior to attempting a new combustion event.
You're thinking linearly. There is a rate of decay with the engine spooling down. I do agree that some percentage of fuel will definitely be expelled during spool down.
Whether that percentage is significant remains to be seen.
I like Brett's approach because by holding down the gas pedal on startup you're cutting fuel and allowing any unspent fuel in the chambers to ejected prior to attempting a new combustion event.
#31
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Of course, the delayed injection is to avoid flooding on the current start, not to fix something left over from the last shutdown.
Ken
Last edited by ken-x8; 01-27-2013 at 10:18 PM.
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