Nitro Engine Exhaust Filtration
12-02-2014, 07:32 AM
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Nitro Engine Exhaust Filtration
Hi, I am a student and I am making a project.
I am producing my own fuel and want to filter the exhaust to make a green vehicle. I know methanol produces just H2O and CO2 which is fine, but the castor oil may smoke and produce hydrocarbons which I want to filter. I am going leave out the nitromethane as I have seen people run the engine without it on youtube (just methanol and oil).
Does anyone know of a small exhaust filter or catalytic converter I could make/use? Also has anyone had experience with running their car with just methanol and oil and the adjustments that need to be made? Any help is very appreiciated, I am new to the RC hobby.
Thank you,
curiousyooper
I am producing my own fuel and want to filter the exhaust to make a green vehicle. I know methanol produces just H2O and CO2 which is fine, but the castor oil may smoke and produce hydrocarbons which I want to filter. I am going leave out the nitromethane as I have seen people run the engine without it on youtube (just methanol and oil).
Does anyone know of a small exhaust filter or catalytic converter I could make/use? Also has anyone had experience with running their car with just methanol and oil and the adjustments that need to be made? Any help is very appreiciated, I am new to the RC hobby.
Thank you,
curiousyooper
12-02-2014, 11:14 AM
#2
Nitromethane is an oxidizer which means it carries oxygen molecules in it and quite a bit of it at that. It isn't necessary to use nitromethane in glow fuel. Nitromethane does allow a wider tuning "window" which means peak mixture could be obtained with less needle adjustments. Using no nitro in an engine designed for 20% nitro will cause the window be narrower. 1/4 turn could go from way rich to way lean whereas it could be 1/2 turn with 20% nitro. Performance suffers a bit when not using nitro - removing the head shims can help with this as methanol fuel needs a higher compression ratio to burn properly. An engine may not idle as well without nitro so a hotter glow plug will greatly improve the idle quality.
As as far as a filter or catalytic converter usage - there are a number of reasons why this wouldn't be ideal. Any time of filtering media will quickly get loaded with oil causing a lot of back pressure and thus making the fuel mixture get quite rich. Also, glow fuel in a 2-cycle engine doesn't burn very hot so any type of catalytic converter won't get hot enough on its own to be effective. Besides that, the catalytic reaction between methanol and platinum is what allows a glow engine to operate. Any unburned fuel entering a platinum containing converter device could in theory cause fire/combustion in the exhaust system. This wouldn't be good.
Just my 2 cents.
As as far as a filter or catalytic converter usage - there are a number of reasons why this wouldn't be ideal. Any time of filtering media will quickly get loaded with oil causing a lot of back pressure and thus making the fuel mixture get quite rich. Also, glow fuel in a 2-cycle engine doesn't burn very hot so any type of catalytic converter won't get hot enough on its own to be effective. Besides that, the catalytic reaction between methanol and platinum is what allows a glow engine to operate. Any unburned fuel entering a platinum containing converter device could in theory cause fire/combustion in the exhaust system. This wouldn't be good.
Just my 2 cents.
12-02-2014, 12:08 PM
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...if you want to be green then do not use a toy car at all.
Model engines are generally very inefficient......
Personally I have some fun and do not care about the planet...little me burning a few gallons of nitro fuel will not compare to planes or drag cars...or....etc.
Quite an interesting thing on UK television recently made me laugh...Brian Cox...talking about some space rocket burning 2.5 tonnes of fuel in 2 minutes or so...
I will not burn that amount of fuel in my lifetime...
Model engines are generally very inefficient......
Personally I have some fun and do not care about the planet...little me burning a few gallons of nitro fuel will not compare to planes or drag cars...or....etc.
Quite an interesting thing on UK television recently made me laugh...Brian Cox...talking about some space rocket burning 2.5 tonnes of fuel in 2 minutes or so...
I will not burn that amount of fuel in my lifetime...
12-02-2014, 02:24 PM
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Thanks guys. 1QWkSport2.5r can you recommend me a hot glow plug to enhance the idle? And Anthroop, the car is green because the fuel is made from recycled wood scraps through pyrolysis. This is for a contest at the university I attend. Also the byproducts are not harmful to humans, given I can get the hydrocarbons from the oil. (the judges will disqualify me for hazardous smoke as the contest is held indoors.)
If nobody knows of a way to filter the exhaust without the problem of back pressure, is there an oil that can be used with a ridiculously high smoke point?
Thank you
If nobody knows of a way to filter the exhaust without the problem of back pressure, is there an oil that can be used with a ridiculously high smoke point?
Thank you
12-02-2014, 02:51 PM
#5
Perhaps a more elaborate (than your typical) muffler with additional chambers / baffles to trap the oil?
"Air / oil seperator" ... check it out (google / yahoo) they are frequently used on full scale aircraft engines. Look and see if you can comeup with an expansion chamber style muffler that has more "gizmos" (technical term
) for the oil to cling to or collect on internally rather than getting spewed out the end of the pipe. Keep it light and compact as possable.
You could put a drain tube on the bottom somewhere, and run a small line to a small catch tank, so the oil wouldn't build up inside the muffler.
You're not gonna get all of it, but I'm sure, w/ careful design, you could come up w/ something that would dump less oil on the ground or into the air. (and it probably would be a lot quieter too)
A mildly timed sport engine that uses a muffler similar to what model airplane engines use, would be a better choice of power than a higher strung, high performance type...IMO.
"Air / oil seperator" ... check it out (google / yahoo) they are frequently used on full scale aircraft engines. Look and see if you can comeup with an expansion chamber style muffler that has more "gizmos" (technical term
) for the oil to cling to or collect on internally rather than getting spewed out the end of the pipe. Keep it light and compact as possable.You could put a drain tube on the bottom somewhere, and run a small line to a small catch tank, so the oil wouldn't build up inside the muffler.
You're not gonna get all of it, but I'm sure, w/ careful design, you could come up w/ something that would dump less oil on the ground or into the air. (and it probably would be a lot quieter too)
A mildly timed sport engine that uses a muffler similar to what model airplane engines use, would be a better choice of power than a higher strung, high performance type...IMO.
Last edited by proptop; 12-02-2014 at 02:56 PM.
12-02-2014, 06:10 PM
#6
First I have to ask, does everyone have to use a glow engine?
If yes then consider using ethyl alcohol and not methanol. Make a moonshine still
. Methanol is deadly poisonous and not all of it burns so if you're running the engine in an enclosed space you'll be pumping a poison into the room. Use castor oil at around 25-30% with ethanol to get adequate lubrication because ethanol has a much higher air/fuel ratio than methanol. Castor oil doesn't burn in the combustion process and what appears to be smoke is just tiny droplets of the oil and its only side effect is that it's a laxative .
If there's a choice of engine types then look at something else like a spark ignition engine with a wet sump so oil doesn't need to be mixed with the fuel and I'd suggest using ethanol once again.
The greenest possible engine I can think of off the top of my head would be to use solar panels to electrolyse water into hydrogen and oxygen then burn it in an engine which can't admit any air to prevent any oxides of nitrogen forming. That should get you full marks, especially if you can collect all the exhaust and drink it.
If yes then consider using ethyl alcohol and not methanol. Make a moonshine still
. Methanol is deadly poisonous and not all of it burns so if you're running the engine in an enclosed space you'll be pumping a poison into the room. Use castor oil at around 25-30% with ethanol to get adequate lubrication because ethanol has a much higher air/fuel ratio than methanol. Castor oil doesn't burn in the combustion process and what appears to be smoke is just tiny droplets of the oil and its only side effect is that it's a laxative .If there's a choice of engine types then look at something else like a spark ignition engine with a wet sump so oil doesn't need to be mixed with the fuel and I'd suggest using ethanol once again.
The greenest possible engine I can think of off the top of my head would be to use solar panels to electrolyse water into hydrogen and oxygen then burn it in an engine which can't admit any air to prevent any oxides of nitrogen forming. That should get you full marks, especially if you can collect all the exhaust and drink it
.
12-02-2014, 06:36 PM
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No, absolutely not, teams have used all sorts of powering reactions in the past, and many have used fuel cells as well. At the last Chem-E-Car competition we made a zinc-air battery that made 12 volts and 5 amps.
My first thought was to convert a weed wacker engine to ethanol actually. The only problem is the time it takes to make ethanol vs methanol. Methanol is made through pyrolysis (burning wood in the absence of oxygen) and is much faster than the fermentation process and distillation used to make ethanol. Another push towards the methanol route is there is a professor at my university who spends a lot of time researching pyrolysis and has access to the equipment.
So, do you know how inefficient the combustion of methanol is in nitro engines? Or how much methanol vapor ends up in the air? Perhaps if I go on with this exhaust modification with filtration I could catch the methanol vapor too. My group also came up with an idea to cool the exhaust to condense the vapor into a liquid. Again energy must be conserved so we would need something to power the condensor around the exhaust pipe. (essentially we are using the nitromotor as a generator with a DC motor to power another DC motor as the drive motor as well as other electronic components.)
I have to say this a wonderful community, full of knowledge
Thanks,
curious yooper
My first thought was to convert a weed wacker engine to ethanol actually. The only problem is the time it takes to make ethanol vs methanol. Methanol is made through pyrolysis (burning wood in the absence of oxygen) and is much faster than the fermentation process and distillation used to make ethanol. Another push towards the methanol route is there is a professor at my university who spends a lot of time researching pyrolysis and has access to the equipment.
So, do you know how inefficient the combustion of methanol is in nitro engines? Or how much methanol vapor ends up in the air? Perhaps if I go on with this exhaust modification with filtration I could catch the methanol vapor too. My group also came up with an idea to cool the exhaust to condense the vapor into a liquid. Again energy must be conserved so we would need something to power the condensor around the exhaust pipe. (essentially we are using the nitromotor as a generator with a DC motor to power another DC motor as the drive motor as well as other electronic components.)
I have to say this a wonderful community, full of knowledge
Thanks,
curious yooper
12-07-2014, 10:20 PM
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Two stroke internal combustion engines are about as dirty as they come. It's not practical to clean them to reasonable levels. That's why many if not most, have been replaced by 4 strokes. I'd chose something cleaner to start with.
