H
HoughMade
Guest
My friend, you are in the 4 stroke forum.
jimraysr
Member
Compressor MOTOR Cooling
My concern and point was that the electric motor in a hermetic compressor (sealed up like a light bulb) is cooled by suction gas coming from the evaporator. Now in a refrigerator there isn't much there to cool the motor, so they used the oil to radiate the heat. In an air conditioning compressor the gas leaving the evaporator is 30 - 45 degrees F (40 to 60 degree conditioned air into the space) and that gas is still cool when it reaches the compressor. The point of no sparks from the motor is correct. There are no switches or other arc producers inside the tin can.
Even if there was, consider there isn't any oxygen in there to mix with an explosive gas.
Back to the refrigeration cycle for a moment. The cool low temperature gas coming to the compressor is compressed and that makes all the heat from the evaporator fit in a much smaller space so the temperature goes up. (plus add in the motor heat and the heat of compression) Then it goes on to the condenser where the air temperature going through it is much cooler than the gas, so the refrigerant in the tubes is cooled and turns back into a liquid. From there through the orifice at the inlet of the evaporator and it sprays into the low pressure area of the evaporator and boils off, taking the heat to do that from the tubes and the fins of the evaporator. All to be repeated over and over.
Lubing a 2 cycle motor running on propane would be just like my Yamaha 175 trail that is not a premix. The oil is pumped into the intake past the carb. and the stroke of the pump is controlled by the throttle position. Goes as high as 250:1 as I recall.
The cascaded refrigeration term used below, just means one system cooling an other one in order to reach a much lower temperature. Two stage would be an other way to thing of it. Space labs use these systems to simulate outer space to test sensors.
My concern and point was that the electric motor in a hermetic compressor (sealed up like a light bulb) is cooled by suction gas coming from the evaporator. Now in a refrigerator there isn't much there to cool the motor, so they used the oil to radiate the heat. In an air conditioning compressor the gas leaving the evaporator is 30 - 45 degrees F (40 to 60 degree conditioned air into the space) and that gas is still cool when it reaches the compressor. The point of no sparks from the motor is correct. There are no switches or other arc producers inside the tin can.
Even if there was, consider there isn't any oxygen in there to mix with an explosive gas.
Back to the refrigeration cycle for a moment. The cool low temperature gas coming to the compressor is compressed and that makes all the heat from the evaporator fit in a much smaller space so the temperature goes up. (plus add in the motor heat and the heat of compression) Then it goes on to the condenser where the air temperature going through it is much cooler than the gas, so the refrigerant in the tubes is cooled and turns back into a liquid. From there through the orifice at the inlet of the evaporator and it sprays into the low pressure area of the evaporator and boils off, taking the heat to do that from the tubes and the fins of the evaporator. All to be repeated over and over.
Lubing a 2 cycle motor running on propane would be just like my Yamaha 175 trail that is not a premix. The oil is pumped into the intake past the carb. and the stroke of the pump is controlled by the throttle position. Goes as high as 250:1 as I recall.
The cascaded refrigeration term used below, just means one system cooling an other one in order to reach a much lower temperature. Two stage would be an other way to thing of it. Space labs use these systems to simulate outer space to test sensors.
motorbikemike45
Member
I remember when FIAT decided to stop producing the 124 spyder sports car because it wasn't sold in enough numbers to make it worthwhile to clean up the engine to meet emission laws. Pininfarina, the designer, was building the bodies for FIAT and wanted to take over production, buying the running gear from FIAT and converting the engine to propane to meet emission laws. To the best of my memory this was in the mid seventies. The car continued in production as a Pininfarina 124 for 5 or 6 years and was something of a success on propane. Fuel mileage and performance suffered somewhat and it wasn't always convenient to find a propane dealer to fill up at night or during holidays. I still see one in local car shows from time to time and the owner loves it. It makes that funky exhaust smell like a propane powered forklift.
H
HoughMade
Guest
Some Morgans were sold in the U.S. converted to Propane for the same reason.
http://www.time.com/time/specials/2007/article/0,28804,1658545_1658533_1658029,00.html
http://www.time.com/time/specials/2007/article/0,28804,1658545_1658533_1658029,00.html
moondog
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Four strokes do not need oil in the air/fuel mixture like two strokes.
One of my employees left to go work for a propane conversion company in 1980. He would visit with various vehicles modified, some were hi performance cars, propane has a high octane number(104) they could take advantage of this in high compression engines, but still had issues with valve seat recession. Todays mini four strokes are built to run on unleaded so conversion to propane is not an issue.
The biggest drawback at the time were DOT legal propane cylinders, this might be something to consider if you are operating on a public highway with propane. Check your motor vehicle laws.
jimraysr
Member
Dot Propane Cylinders
Interesting and yet there is no problem with propane cylinders on RVs? We run with a 40# horizontal under frame gas feed tank for cooking, hot water and furnace. Some also run their generator as well from propane, but those use a liquid feed tank (like fork lifts) rather than gas feed outlets.
Not sure at what feed rate you would need to have a liquid feed? I am sure a furnace uses more than a 50cc 4 stroke. All has to do with the BTUs. I have a fork lift tank, but it would require a trailer. )
Jim
Interesting and yet there is no problem with propane cylinders on RVs? We run with a 40# horizontal under frame gas feed tank for cooking, hot water and furnace. Some also run their generator as well from propane, but those use a liquid feed tank (like fork lifts) rather than gas feed outlets.
Not sure at what feed rate you would need to have a liquid feed? I am sure a furnace uses more than a 50cc 4 stroke. All has to do with the BTUs. I have a fork lift tank, but it would require a trailer. )
Jim
I think the issue with cars was the size of the tank, I'm trying to find the info I had on this.They were putting 2 80 lb size bottles in the cars, RVs use 40 lb.
If the bottles are DOT approved there is no problem, the issue is with non DOT bottles.
I would still make an attempt at checking the local laws.
If the bottles are DOT approved there is no problem, the issue is with non DOT bottles.
I would still make an attempt at checking the local laws.
AussieJester
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Soz fellas i clicked on the "New Posts" link i totally missed this was the 4 stroke thread..apologies.
RE: gas cyclinders...yes would be difficult getting a tank small enough that will pass inspection ...i do recall a recent ep of American Chopper...(torrent -->american.chopper.s06e12.hdtv.xvid-gnarly if anyone wishes to download and watch it) They built a natural gas powered chopper for Chesepeake Energy, the gas tank used on that was too big for a motored bicycle by a long shot BUT you could possible start with the company the bike was built and see what tanks are available and in what size, the chopper was road licensed so the tank would of have to been "legal"
Best of luck anywayz chaps would love to see a custom build powered by gas
KiM
EDIT: i just had an idea...the small small 65 cu feet of air capable scuba tanks? they are rated to something ridiculous 3000psi possibly use one of them pumped to the eyeballs with gas?...just a thought...they come in alloy and steel an wuld easily fit the top bar of adult mountain bike or beach druiser style bike.
RE: gas cyclinders...yes would be difficult getting a tank small enough that will pass inspection ...i do recall a recent ep of American Chopper...(torrent -->american.chopper.s06e12.hdtv.xvid-gnarly if anyone wishes to download and watch it) They built a natural gas powered chopper for Chesepeake Energy, the gas tank used on that was too big for a motored bicycle by a long shot BUT you could possible start with the company the bike was built and see what tanks are available and in what size, the chopper was road licensed so the tank would of have to been "legal"
Best of luck anywayz chaps would love to see a custom build powered by gas
KiM
EDIT: i just had an idea...the small small 65 cu feet of air capable scuba tanks? they are rated to something ridiculous 3000psi possibly use one of them pumped to the eyeballs with gas?...just a thought...they come in alloy and steel an wuld easily fit the top bar of adult mountain bike or beach druiser style bike.
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