We really need to ditch reciprocating motion once and for all.
We kindda' get stuck in the way we see things, sometimes...... Detenating explosive materal within a semi-closed vessel to produce power seems so..............primative.
As soon as we discover the 8th ray of Barsoom, things will be different. Although killing will remain pretty much the same. Just spill out the juices.
[This message has been edited by Boondawg (edited 03-06-2011).]
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08:24 PM
htexans1 Member
Posts: 9110 From: Clear Lake City/Houston TX Registered: Sep 2001
would'nt the piston and combustion chamber tend to have more wear on the bottom since it will be laying there sliding back and forth? he said that the crank shaft would turn twice as many RPM's if it were developed in a standard duty vehicle, going down the road at 65mph 2500 or 3000 rpms (normally) now double that,.. seems like it might shorten the life of the crank assembly dont ya think?
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08:38 PM
Boondawg Member
Posts: 38235 From: Displaced Alaskan Registered: Jun 2003
Originally posted by $Rich$: would'nt the piston and combustion chamber tend to have more wear on the bottom since it will be laying there sliding back and forth? he said that the crank shaft would turn twice as many RPM's if it were developed in a standard duty vehicle, going down the road at 65mph 2500 or 3000 rpms (normally) now double that,.. seems like it might shorten the life of the crank assembly dont ya think?
would'nt the piston and combustion chamber tend to have more wear on the bottom since it will be laying there sliding back and forth? he said that the crank shaft would turn twice as many RPM's if it were developed in a standard duty vehicle, going down the road at 65mph 2500 or 3000 rpms (normally) now double that,.. seems like it might shorten the life of the crank assembly dont ya think?
In a standard duty vehicle going 65 at 2500-3000 rpms, the crankshaft would be going 3000 rpms, so the pistons would only be doing 1500. Crank life would be the same - less wear on the reciprocating assy.
Also, even in a V engine, the pistons are laying over on one side, just not flat, so that would already be a known issue if there's any concern, and since it's not a variable position, it would be taken into consideration during design.
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10:39 PM
Boondawg Member
Posts: 38235 From: Displaced Alaskan Registered: Jun 2003
Originally posted by Formula88: Also, even in a V engine, the pistons are laying over on one side, just not flat, so that would already be a known issue if there's any concern, and since it's not a variable position, it would be taken into consideration during design.
Opposed piston engines have been done before. The napier deltic engine has three banks of opposed pistons with three crankshafts, similar idea just a different implementation.
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11:49 PM
spark1 Member
Posts: 11159 From: Benton County, OR Registered: Dec 2002
We used these motors (two opposed cylinders) to power home made go-karts back when:
The new design is interesting but has several more moving parts than a recip so it may be less reliable. Also, it may be difficult to meet emissions standards with a two stroke engine. That's not a problem in a military vehicle but it may limit its use in other applications.
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11:51 PM
Mar 7th, 2011
Stubby79 Member
Posts: 7064 From: GFY county, FY. Registered: Aug 2008
I don't think emissions, in a direct-injection setup like this, would be an issue. There's no reason to be running 2-stroke oil in this scenario - the engine can use a proper oiling system - so all they have to do is make sure all the fuel is burnt by the time the exhaust port opens up. That'd be even easier with disel, imho.
If you don't actually watch the video you wouldn't get the point that this is not a "flat" opposing cylinder engine in the standard way. The beauty of the design is the balance and lack of vibration, but the problem with the design is making it strong. It is also are really short stroke engine. The valving on the 2 stroke is also so simple and relatively trouble free that if you got the strength issues resolved and the oiling sorted out, it could be a really nice power plant for the small cars.
Arn
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08:58 AM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
Originally posted by Nurb432: We really need to ditch reciprocating motion once and for all.
yes...but, with what we know today - internal combustion is still the most effeicent way to extract power from combustion
tho - just yesterday I was pondering the possibilities of converting a steam engine design to continous combustion a combustion chamber feeding a bank of steam engine pistons
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11:02 AM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
Originally posted by Arns85GT: If you don't actually watch the video you wouldn't get the point that this is not a "flat" opposing cylinder engine in the standard way. The beauty of the design is the balance and lack of vibration, but the problem with the design is making it strong. It is also are really short stroke engine. The valving on the 2 stroke is also so simple and relatively trouble free that if you got the strength issues resolved and the oiling sorted out, it could be a really nice power plant for the small cars.
Arn
even balanced and all - that long arm pushing the outside piston is ALOT of moving mass but - the way shorter stroke does compansate for that a little - but - I dont think enough
even balanced and all - that long arm pushing the outside piston is ALOT of moving mass but - the way shorter stroke does compansate for that a little - but - I dont think enough
That looooong connecting rod to the outside piston isn't pushing, it's always pulling. That's the key point for this engine. If it's always in tension, it doesn't matter how long it is. The inside con rod is always in compression, but it can be really short. And preventing the load from going from full tension to full compression (like in a normal engine) reduces fatigue loads by half.
Like many have pointed out, it is a variation on themes that have been tried before. I hope it works out as well as these guys think it will.
After all, it's OUR money they're spending.
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12:35 PM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
Originally posted by Zeb: That looooong connecting rod to the outside piston isn't pushing, it's always pulling. That's the key point for this engine. If it's always in tension, it doesn't matter how long it is. The inside con rod is always in compression, but it can be really short. And preventing the load from going from full tension to full compression (like in a normal engine) reduces fatigue loads by half.
Like many have pointed out, it is a variation on themes that have been tried before. I hope it works out as well as these guys think it will.
After all, it's OUR money they're spending.
doesnt change the fact that is is heavy reciprocating mass. not sure if using a "OHC" type of design would help
it is a good compact design for power - 2-cycle & short stroke for high RPMS. but - it is still 2 cycle - which means sloppy fuel use & sloppy exhaust. will NEVER be in consumer vehicles.
doesnt change the fact that is is heavy reciprocating mass. not sure if using a "OHC" type of design would help
it is a good compact design for power - 2-cycle & short stroke for high RPMS. but - it is still 2 cycle - which means sloppy fuel use & sloppy exhaust. will NEVER be in consumer vehicles.
“640K ought to be enough for anybody.” Bill Gates, Chairman, Microsoft, 1981
“The bomb will never go off. I speak as an expert in explosives.” Admiral William Leahy, Manhattan Project, 1943
The dangers are obvious. Stores of gasoline in the hands of people interested primarily in profit would constitute a fire and explosive hazard of the first rank. Horseless carriages propelled by gasoline might attain speeds of 14 or even 20 miles per hour. The menace to our people of vehicles of this type hurtling through our streets and along our roads and poisoning the atmosphere would call for prompt legislative action even if the military and economic implications were not so overwhelming... [T]he cost of producing [gasoline] is far beyond the financial capacity of private industry... In addition the development of this new power may displace the use of horses, which would wreck our agriculture. - U. S. Congressional Record, 1875.
The horse is here to stay, but the automobile is only a novelty—a fad. - Advice from a president of the Michigan Savings Bank to Henry Ford's lawyer Horace Rackham. Rackham ignored the advice and invested $5000 in Ford stock, selling it later for $12.5 million.
That the automobile has practically reached the limit of its development is suggested by the fact that during the past year no improvements of a radical nature have been introduced. - Scientific American, Jan. 2, 1909.
There is not the slightest indication that [nuclear energy] will ever be obtainable. It would mean that the atom would have to be shattered at will. - Albert Einstein, 1932.
There is no reason for any individual to have a computer in their home. - Kenneth Olsen, president and founder of Digital Equipment Corp., 1977. Just saying.
Brad
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12:57 PM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
^ lol - good point but - 2-cycle has been around for a long time, and has already been abandoned for consumer vehciles. I suppose there still might be some motorcycles. and they do get used in boats & specialized race cars. they are awesome engines when you hit their RPM "sweet spot" - basicly 2x the HP of the same size motor as a 4-cycle. but - the 2 cycle has that one flaw: fuel wasted by going out the exhaust. just a basic reality of the design.
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02:08 PM
Mickey_Moose Member
Posts: 7497 From: Edmonton, AB, Canada Registered: May 2001
Well the title is a bit misleading as they are talking about an opposed piston/opposed cylinder engine.
Opposed cylinders have been around for a long time - we still have an old 1947 John Deere AR tractor out on the farm that has a opposed 2 cylinder engine.
“640K ought to be enough for anybody.” Bill Gates, Chairman, Microsoft, 1981
“The bomb will never go off. I speak as an expert in explosives.” Admiral William Leahy, Manhattan Project, 1943
The dangers are obvious. Stores of gasoline in the hands of people interested primarily in profit would constitute a fire and explosive hazard of the first rank. Horseless carriages propelled by gasoline might attain speeds of 14 or even 20 miles per hour. The menace to our people of vehicles of this type hurtling through our streets and along our roads and poisoning the atmosphere would call for prompt legislative action even if the military and economic implications were not so overwhelming... [T]he cost of producing [gasoline] is far beyond the financial capacity of private industry... In addition the development of this new power may displace the use of horses, which would wreck our agriculture. - U. S. Congressional Record, 1875.
The horse is here to stay, but the automobile is only a novelty—a fad. - Advice from a president of the Michigan Savings Bank to Henry Ford's lawyer Horace Rackham. Rackham ignored the advice and invested $5000 in Ford stock, selling it later for $12.5 million.
That the automobile has practically reached the limit of its development is suggested by the fact that during the past year no improvements of a radical nature have been introduced. - Scientific American, Jan. 2, 1909.
There is not the slightest indication that [nuclear energy] will ever be obtainable. It would mean that the atom would have to be shattered at will. - Albert Einstein, 1932.
There is no reason for any individual to have a computer in their home. - Kenneth Olsen, president and founder of Digital Equipment Corp., 1977. Just saying.
Brad
Interesting that the most recent quote was from 1981, making it 30 years old this year, and more importantly was in reference to a then-immature technology that little was known about. Remember, though transistors had been around for many decades at that time binary digital computers and software for consumer use had not so there was no real basis for extrapolation on memory usage. On the other hand, piston engine technology has been around for well over a century so the understanding of the physics and mechanics is well understood now, especially with tools like CFD which didn't even exist back then.
Due care has to be taking to avoid falling for the trap of false equivalency.
------------------ Bring back civility and decorum!
It's possible to understand someone's point of view without accepting it. It's possible to disagree with someone without being rude and nasty about it. Sure it's hard, but nothing worth doing is ever easy, is it?
cool design, but as a child I thought the future of car engines was Chrysler's Turbine.
Me too. In high school, we had a family that had one of the test turbine cars. It was gorgeous and ran flawlessly. Everyone in my auto shop class got to go for a ride. The only drawbacks were the heat of the exhaust (now catalytic coverters are nearly as hot anyway) and it was a bit of a dog from a dead stop. Not any worse than some 4 cyl cars now though. It was smoother and quieter than any Cadillac at the time. It ran the same on any combustible liquid fuel from grain alcohol to kerosene and Diesel. If the government had kept its nose out of it, wed be all driving them now. The main- shaft was the only moving part. You might have to replace the bearings it rode in every 200,000 miles.
Me too. In high school, we had a family that had one of the test turbine cars. It was gorgeous and ran flawlessly. Everyone in my auto shop class got to go for a ride. The only drawbacks were the heat of the exhaust (now catalytic coverters are nearly as hot anyway) and it was a bit of a dog from a dead stop. Not any worse than some 4 cyl cars now though. It was smoother and quieter than any Cadillac at the time. It ran the same on any combustible liquid fuel from grain alcohol to kerosene and Diesel. If the government had kept its nose out of it, wed be all driving them now. The main- shaft was the only moving part. You might have to replace the bearings it rode in every 200,000 miles.
What was the gas mileage on that back then? IIRC it was really bad, in the low to mid single digits. The advantage of a mobile turbine is power density, you get a lot of power out of a small package, but the inherent disadvantage is that you burn a lot more fuel in proportion to the power generated than in a piston engine. There are a lot of things you can add on to make it better but then it gets too big and unwieldy; those things are more typically done on fixed turbines like power plants where size and weight don't really matter all that much.
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