|
Temprature:
What I forsee happening by adding gasoline vapor is if the air temperature isn't high enough to keep it vaporized it will condense back into liquid droplets. But if the intake temperature is high, the chances of detonation go up meaning you have to lower your compression ratio and/or retard the timing, both of which will hurt fuel efficiency.
A change of state, from a liquid takes a fair amount of energy, and to condense a vapor takes the removal of a fair amount of energy, in other words to get vapor you need to really heat if up and to turn it back into a liquid you need to do a lot of cooling.
Stuff has a tenancy to stay in the state it is in. My understanding gasoline once vaporized will stay as a vapor for some time unless acted apron by a drastic temperature drop.
And even if you could get it into a gaseous state in cool air, the liquid fuel droplets act as a way to cool the charge to prevent detonation. So again, you'd have to lower the compression ratio or retard the timing or use higher octane fuel. This is why natural gas is a good fuel for this since it's already a gas and it also has an extremely high level of octane.
And again, once in a vapor state there will be NO liquid droplets to cool the mix, and they do that because of their absorbing heat as they are changing state into vapor and it will all BE VAPOR.
Timing will indeed need to cut back, to zero most likely as unlike gasoline droplets which need time to be vaporized BY the early start of combustion, vapor will flash burn producing more pure power to drive the piston and in correctly metered be completely consumed at the end of the combustion cycle and there will be no farther burn, thus much less engine heat. Also as there is no early start of combustion they will not be expanding gassed for the piston to fight as it tries to compress them. This could also add to the power output.
One drawback to gaseous fuels is you get less power. But that can be a good thing for fuel mileage. Since gasses take up more space than liquids, you get less air into the cylinder, and therefore less fuel to maintain a correct AFR. That also means you have to keep your throttle more open, resulting in less pumping losses.
And here you thinking of the other vapor fuels which contain less BTUs that gasoline, all the power gasoline make is from its vapor state, liquid does not burn.
But what could be helpful is extreme atomization. If you could make the fuel as fine of a mist as possible that would help on most all accounts. Maybe gasifying gasoline and feeding it into air that cools it into a fog-like mist would be the key. Or just finding other ways to get it as fine as possible. Ultrasonic vibrations? Of course avoiding things that deatomize fuel are just as important. Making the intake stream bend as little as possible with as few vortices as possible so that fuel doesn't get flung out of the air, for an example.
You’re talking the current state of thinking….finer and finer atomization. ALL to TRY to help those droplets vaporized more…none the less there is still left over fuel otherwise they would remove the cats as they would no longer be needed to clean up the unburned fuel.
Rich
|