I thought the following link might interest a few people.
Mayflower e3
When the page loads you want the Mayflower e3 Engine
Variable stroke/compression Engine
Re: Variable stroke/compression Engine
Wow, that is cool. My only concern would be the life span of the linear bearing and its pivot. Then multiply that times 4, 6, or 8?
There was one other variable displacement engine that I had read about recently. Its only purpose was for gasoline refinery to verify octane and anti-knock compounds in the recipe. All refineries use the same engine from the same manufacturer. Interestingly enough, the article pounded the refineries for using octane as a basis for fuel quality. When a more accurate way to measure it would be BTU's. They explained how octane is not the only component in the mixture that adds to or subtracts from the burn efficiency. There was no diffinitive way to measure octane with the exception of getting this little (3 cyl ?) engine to knock with samples of the mixture compared to previous batches.
DC
There was one other variable displacement engine that I had read about recently. Its only purpose was for gasoline refinery to verify octane and anti-knock compounds in the recipe. All refineries use the same engine from the same manufacturer. Interestingly enough, the article pounded the refineries for using octane as a basis for fuel quality. When a more accurate way to measure it would be BTU's. They explained how octane is not the only component in the mixture that adds to or subtracts from the burn efficiency. There was no diffinitive way to measure octane with the exception of getting this little (3 cyl ?) engine to knock with samples of the mixture compared to previous batches.
DC
Re: Variable stroke/compression Engine
With the correct materials i don't think the life span of the linear bearing would be a major problem.
The octane rating of fuel has nothing to do with the quality of the fuel. The octane is a measurement of how hard it is to get the fuel to burn. i.e. the higher the octane rating, the quicker/hotter the fuel burns.
That's why if you change from leaded to unleaded petrol you have to retard the ignition timing a few degrees.
Using BTUs as way of classing fuel would be inconsistant, as you could have 2 fuels with XXbtu rating but completely different octane ratings.
Just to confuse people, the cetane rating of diesel is a measurement of how easy the fuel burns.
The octane rating of fuel has nothing to do with the quality of the fuel. The octane is a measurement of how hard it is to get the fuel to burn. i.e. the higher the octane rating, the quicker/hotter the fuel burns.
That's why if you change from leaded to unleaded petrol you have to retard the ignition timing a few degrees.
Using BTUs as way of classing fuel would be inconsistant, as you could have 2 fuels with XXbtu rating but completely different octane ratings.
Just to confuse people, the cetane rating of diesel is a measurement of how easy the fuel burns.
Re: Variable stroke/compression Engine
That is correct. Octane does have nothing to do with quality. Although the marketing makes it a misunderstood connection to quality.
I think that portion of the article was picking at the marketing hype that goes with the dollar value in octane rating. Therefore the point of BTU's/pound of fuel may be a more reliable measure for what quality you are actually purchasing. Their data for various gasolines compared octane against BTU's. Hands down showed that the amount of power produced was not part of the consumers knowledge in what they were paying for. The octane rating varied little, but the BTU ratings were all over the field. The authors conclusion was that no governing authority on this issue alone was cause for burning an excessive amount of junk that produces less power/unit of exhaust gasses than need be.
From my understanding, octane is one of the anti-knock compounds that helps combustion speed to prevent pre-detonation. That changes with compression ratio/self detonating, which is also why retarding the timing helps reduce knock. Which surprisingly...I did not catch any mention of with the Mayflower engine? They must have it handled somehow.
DC
I think that portion of the article was picking at the marketing hype that goes with the dollar value in octane rating. Therefore the point of BTU's/pound of fuel may be a more reliable measure for what quality you are actually purchasing. Their data for various gasolines compared octane against BTU's. Hands down showed that the amount of power produced was not part of the consumers knowledge in what they were paying for. The octane rating varied little, but the BTU ratings were all over the field. The authors conclusion was that no governing authority on this issue alone was cause for burning an excessive amount of junk that produces less power/unit of exhaust gasses than need be.
From my understanding, octane is one of the anti-knock compounds that helps combustion speed to prevent pre-detonation. That changes with compression ratio/self detonating, which is also why retarding the timing helps reduce knock. Which surprisingly...I did not catch any mention of with the Mayflower engine? They must have it handled somehow.
DC
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J_Tiers
Re: Variable stroke/compression Engine
A while back I bought an 8 horse Kohler that a guy here had been using as a base for developing some funny compression system.
The con rod and piston (which I still have somewhere) were set up with an offset that I never did figure out the exact purpose of.
Bought it from an estate, I never knew the guy who was working with it. Name of Baureidl, something like that.
Anyhow, I never tried his system, although there was some nice machining (and some lousy) in it. Just bought an oversize piston and rod and got it going.
Got a big Eclipse tank or aircraft 28V generator with it that he was using as a load, too.
The con rod and piston (which I still have somewhere) were set up with an offset that I never did figure out the exact purpose of.
Bought it from an estate, I never knew the guy who was working with it. Name of Baureidl, something like that.
Anyhow, I never tried his system, although there was some nice machining (and some lousy) in it. Just bought an oversize piston and rod and got it going.
Got a big Eclipse tank or aircraft 28V generator with it that he was using as a load, too.
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captainkirk
Re: Variable stroke/compression Engine
I think you have it backwards as to octane ratings, the higher the octane rating the higher the resistance to pre ignition. This translates to the slower it is to ignite. Higher octane fuels also are not as hot and make less power than lower octane fuels. Its hard to understand that if you buy higher priced fuel with a higher octane rating your engine will make less hp, it's sort of a complicated issue, but if your engine wasn't built to use high test fuel and doesn't knock when run on lower octane fuel you will make more power on the low octane.
Re: Variable stroke/compression Engine
In the last two or so, I have read of a Saab? (I think) variable compression ratio engine. It appears to pivot one side of the engine block, so the block can be lifted or lowered inrelation to the crankshaft. Seemed quite doable.