new valveless opposed piston engine
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http://www.ecomotors.com/ecomotors-inter...e-commercial-ve
Navistar, Generac, other major engine manufactures are designing and intend to build production models.
As mpvue pointed out, the rotary engine has never really been a success. The surface to volume ratio of the combustion chamber is awful, basic physics never did give this engine much of a chance at good efficiency. Yes, I do know about the fun factor!!
Gas turbines would work great IF we would put a 25 hp turbine in our cars and accept very slow acceleration (more like "gathering speed"), and allow top speed to settle out at maybe 70 mph using full throttle. But turbines (basically a series of fans and propellers) loose all their effective compression ratio at part throttle..... low fan speeds... and part throttle efficiency is miserable. A 300 hp engine at low speeds guzzles a large percentage of its full throttle fuel demand, while doing nearly nothing.
Piston engines seem to rule.... maybe OPOC 2 strokes are the next step.
Navistar, Generac, other major engine manufactures are designing and intend to build production models.
As mpvue pointed out, the rotary engine has never really been a success. The surface to volume ratio of the combustion chamber is awful, basic physics never did give this engine much of a chance at good efficiency. Yes, I do know about the fun factor!!
Gas turbines would work great IF we would put a 25 hp turbine in our cars and accept very slow acceleration (more like "gathering speed"), and allow top speed to settle out at maybe 70 mph using full throttle. But turbines (basically a series of fans and propellers) loose all their effective compression ratio at part throttle..... low fan speeds... and part throttle efficiency is miserable. A 300 hp engine at low speeds guzzles a large percentage of its full throttle fuel demand, while doing nearly nothing.
Piston engines seem to rule.... maybe OPOC 2 strokes are the next step.
So if they get rid of the valve works, do they control the power by injection pressure and turbo speed? That means they will likely be operate as diesel instead of spark ignition.
Also how do they seal the intake and exhaust port? Is it piston ring or is it a controlled leakage?
I'd also see packaging as a problem for small vehicle, but it is probably not a problem for a big diesel truck.
Interesting design, wish we'd see more of these new concepts that works.
Also how do they seal the intake and exhaust port? Is it piston ring or is it a controlled leakage?
I'd also see packaging as a problem for small vehicle, but it is probably not a problem for a big diesel truck.
Interesting design, wish we'd see more of these new concepts that works.
this is very similar idea.
http://en.wikipedia.org/wiki/Napier_Deltic
very cool looking engine and is very successful for the application.
http://en.wikipedia.org/wiki/Napier_Deltic
very cool looking engine and is very successful for the application.
There are many, many variations on the theme of "internal combustion" .
Today's common car engine is very well refined. Volumetric efficiency, the % of air it can pump related to displacement, is often close to 100% now!
So, pumping losses are related to throttle position. (one reason a diesel is more efficient)
Combustion quality is also very well refined.
Many methods exist for improvement in efficiency. (atkinson cycle, direct injection, high compression, etc)
With that (and more) in mind, just what are we hoping to achieve with such "novel" designs?
Today's common car engine is very well refined. Volumetric efficiency, the % of air it can pump related to displacement, is often close to 100% now!
So, pumping losses are related to throttle position. (one reason a diesel is more efficient)
Combustion quality is also very well refined.
Many methods exist for improvement in efficiency. (atkinson cycle, direct injection, high compression, etc)
With that (and more) in mind, just what are we hoping to achieve with such "novel" designs?
Originally Posted By: Cujet
There are many, many variations on the theme of "internal combustion" .
Today's common car engine is very well refined. Volumetric efficiency, the % of air it can pump related to displacement, is often close to 100% now!
So, pumping losses are related to throttle position. (one reason a diesel is more efficient)
Combustion quality is also very well refined.
Many methods exist for improvement in efficiency. (atkinson cycle, direct injection, high compression, etc)
With that (and more) in mind, just what are we hoping to achieve with such "novel" designs?
Then how would you explain this...
There are many, many variations on the theme of "internal combustion" .
Today's common car engine is very well refined. Volumetric efficiency, the % of air it can pump related to displacement, is often close to 100% now!
So, pumping losses are related to throttle position. (one reason a diesel is more efficient)
Combustion quality is also very well refined.
Many methods exist for improvement in efficiency. (atkinson cycle, direct injection, high compression, etc)
With that (and more) in mind, just what are we hoping to achieve with such "novel" designs?
Then how would you explain this...
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Until the above is verified by independent third party testing i would not consider it fact just yet.
Originally Posted By: sunfire
Originally Posted By: Cujet
There are many, many variations on the theme of "internal combustion" .
Today's common car engine is very well refined. Volumetric efficiency, the % of air it can pump related to displacement, is often close to 100% now!
So, pumping losses are related to throttle position. (one reason a diesel is more efficient)
Combustion quality is also very well refined.
Many methods exist for improvement in efficiency. (atkinson cycle, direct injection, high compression, etc)
With that (and more) in mind, just what are we hoping to achieve with such "novel" designs?
Then how would you explain this...
As completely and utterly useless pseudo information. I'm in the aviation industry, I work with, and clearly understand energy density. I deal with it on a daily basis.
Let's look at the facts:
This design is loaded with complex mechanical features, including internal and external connecting rods, highly loaded gearsets, complex gas flow paths and complex lubrication requirements. Not to mention the far less than ideal, non centrally located injection system.
Tell me again what the "specific output" scale represents... Power to weight, power v. displacement, power to size etc. Because none of those items are in any way positively affected by facing opposed cylinders.
Originally Posted By: Cujet
There are many, many variations on the theme of "internal combustion" .
Today's common car engine is very well refined. Volumetric efficiency, the % of air it can pump related to displacement, is often close to 100% now!
So, pumping losses are related to throttle position. (one reason a diesel is more efficient)
Combustion quality is also very well refined.
Many methods exist for improvement in efficiency. (atkinson cycle, direct injection, high compression, etc)
With that (and more) in mind, just what are we hoping to achieve with such "novel" designs?
Then how would you explain this...
As completely and utterly useless pseudo information. I'm in the aviation industry, I work with, and clearly understand energy density. I deal with it on a daily basis.
Let's look at the facts:
This design is loaded with complex mechanical features, including internal and external connecting rods, highly loaded gearsets, complex gas flow paths and complex lubrication requirements. Not to mention the far less than ideal, non centrally located injection system.
Tell me again what the "specific output" scale represents... Power to weight, power v. displacement, power to size etc. Because none of those items are in any way positively affected by facing opposed cylinders.
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plain and simple it adds more weight. cant be better,
.
.
Opposed engines have been around since the early 1900's
They don't seem to have caught on in a big way, but somehow, for some reason, I like the idea.
The Junkers was used as a Diesel aircraft engine, I guess there must have been some reason for the design (it used Two cranks as well. That must have added some weight) They have been used in several Tanks and as Marine and Locomotive engines. There must be some advantages!!
To me, I see you can have good compression AND (for a while) have an almost spherical combustion chamber! Would that not give good Thermal efficiency?
On the OPOC I see the inner con rod being very short (to help the overall dimensions of the engine, and prevent the outer rods being extremely long?) I don't like this, as it limits stroke.
However the inner and outer pistons stroke need not be the same, Heck, Even the bores could be different!
But, if you take this to an extreme, you end up with a super short stroke inner piston, that does little more than open and close valves for the outer piston!!
In which case you are almost back to a conventional engine (if you substitute the inner piston for a Poppet valve)
I understand the reasoning behind the Deltec was to build a 'Fast' engine using the available shell bearings, Yet get a lot of Cubic inches (capacity) in a small space.
The pitfall seems to be the expense of maintaining the thing:-(
They don't seem to have caught on in a big way, but somehow, for some reason, I like the idea.
The Junkers was used as a Diesel aircraft engine, I guess there must have been some reason for the design (it used Two cranks as well. That must have added some weight) They have been used in several Tanks and as Marine and Locomotive engines. There must be some advantages!!
To me, I see you can have good compression AND (for a while) have an almost spherical combustion chamber! Would that not give good Thermal efficiency?
On the OPOC I see the inner con rod being very short (to help the overall dimensions of the engine, and prevent the outer rods being extremely long?) I don't like this, as it limits stroke.
However the inner and outer pistons stroke need not be the same, Heck, Even the bores could be different!
But, if you take this to an extreme, you end up with a super short stroke inner piston, that does little more than open and close valves for the outer piston!!
In which case you are almost back to a conventional engine (if you substitute the inner piston for a Poppet valve)
I understand the reasoning behind the Deltec was to build a 'Fast' engine using the available shell bearings, Yet get a lot of Cubic inches (capacity) in a small space.
The pitfall seems to be the expense of maintaining the thing:-(
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