Injecting prior to turbo comp' impellers

[hotrod]

Interesting concept!

You would also have the issue of ice crystals forming during the evaporation process, the alcohol will evaporate more rapidly than the water so you get a distillation process as the mist moves down stream. An ice crystals that form would have a more agressive errosive effect on the compressor than the liquid water, so that is one issue to avoid.

With Propane injection you also have a balancing act going on between charge density due to cooling and oxygen dilution by the propane. This increases the volume of gas that must be compressed. As a result of that I would think you are looking for a happy medium where you get the benefits of some charge cooling, some increase in fuel octane, and better vaporization in the combustion chamber without over diluting the intake charge the turbo needs to compress.

Like you mention the cooling effect occurs at the point the liquid changes to gas, so by moving the solenoid to the injection point the cooling would move to the nozzle.
years ago I used to work in a gas station and one of my dutied every night was to blow off the compressed air in a pressure washer tank. In that case the point of expansion was at the outlet valve and that is where the frost formed. It might be ideal in your application to run the liquid propane through a heat exchanger as it expands to capture that cooling power and use a finned heat sink to cool the air charge.

Larry

[cheekychimp]

It might be ideal in your application to run the liquid propane through a heat exchanger as it expands to capture that cooling power and use a finned heat sink to cool the air charge.

Larry

Can you expand upon this Larry, and tell me how the heat exchanger would be linked to cool the air charge.

[hotrod]

Just brain storming a bit.

First you would need to do a bit of experimentation to find out how much cooling occurs near the solenoid and the line between it and the spray nozzle. If that section of line gets really cold you could wrap it in a coil around a segment of tubing and insulate the outside and put some fins on the inside. If that was placed in line with the air intake it would help cool the air charge by using cooling from the expanding propane that would normally be wasted.

If most of the cooling occurs at the propane bottle you would need to determine if there was any practical way to use that cooling to pre-cool the intake air by passing the air charge around the propane bottle. I can imagine a way to do it if you were using the smaller consumer propane bottles intended for propane torches, but not if you were using a proper DOT rated propane bottle in the trunk.

You could also use a wasted propane (or nitrous/CO2) system that just blew off some of the propane, nitrous or CO2 through a heat exchanger, but that would add some concerns about where the extra propane goes and would it be a fire hazard. This would be similar to the cryo cooler systems.

Larry

[cheekychimp]

You would also have the issue of ice crystals forming during the evaporation process, the alcohol will evaporate more rapidly than the water so you get a distillation process as the mist moves down stream. An ice crystals that form would have a more agressive errosive effect on the compressor than the liquid water, so that is one issue to avoid.

What if I injected methanol only? -40 wouldn't freeze alcohol right? I find this stuff interesting but I don't understand physics at all. Water has the ability to absorb far more latent heat than alcohol, but alcohol evaporates faster! So which is better in this situation?

[JohnA]

Originally Posted by cheekychimp

..Water has the ability to absorb far more latent heat than alcohol, but alcohol evaporates faster! So which is better in this situation?

It depends on the efficiency of your compressors and the effectiveness of your current intercooling (as well as how often your cylinder pressures exceed 'safe' levels, mainly Compression Ratio relating to boost)
You might want mostly alcohol before the cylinders and mostly water into the cylinders.

[RICE RACING]

i have only ever used total pre turbo injection (15% of fuel flow).

what i have noticed is no negative performance difference in heat exchanger, mostly increases

same boost
no WI 59deg c charge at end of 400m test
with pre turbo WI 45to 47 deg c same test

the water may boil in compressor but it condenses again leading into IC and def out of it, i can see suspended water vapour clouds in charge pressurized water tank which takes feed just before throttle body. So i get the turbo efficency increase and also in chamber cooling as well for what i have seen.

in practice have run up to 28psi boost on 9:1 comp wankel engine where others are limited to around 20psi maximum on very heavy AFR's and retarded timing, so it def seems to be working. power is there too over different cars which means its not a one off fluke result.

i use a special water/air atomizer on my "ghetto" systems, as a result no compressor wear at all after many 1000's of km in field use. hope thats of some use ?

[JohnA]

Very nice :smile:

[NAnderson]

Originally Posted by RICE RACING

i use a special water/air atomizer on my "ghetto" systems, as a result no compressor wear at all after many 1000's of km in field use. hope thats of some use ?

Could you shed some more light on this "atomizer?" A website or picture possibly? I'm just curious as to what others are using for nozzles for pre-compressor injection.

[fperra]

So much good information here, but no recent follow-up.

[untubbed_20]

http://www.spray.com.au/ss-redir-prod.htm
if you look under the catalogue you will find some info on the SUE18
and the SUE25BDF that others use

go catalogue> air atomizing nozzles>18J and 14J series
than they are either in pressure spray setups- internal mix
pressure spray setups- external mix
cheers
darren