The next phase of the project getting into real world physics will be interesting. I would expect them to try it on smaller scale engines to gather some of the data as they go.
Looks like a perfect glow fuel project since the burn is cooler. That may help in the material and/or valve configuration selection. At least it would offer a platform for timing and power benefits in the short term.
Thanks for bringing it to our attention Philip.
DC
Great New IC Engine Idea
-
captainkirk
Re: Great New IC Engine Idea
It seems to me to be just a deviation from the well know "Supercharging theory" not a new engine design at all just a rather awkward way to compress the incoming charge. Not much of a "new" idea there, they have just cloaked the idea in a "new engine claim" when you boil it down supercharging a two stroke engine has been done many times in the past I would look towards those attempts success and failure rates. Just my initial thoughts as they say"your mileage may vary"
Re: Great New IC Engine Idea
Hello Kirk
The principle here is not to increase the volumetric efficiency by packing more mixture into the cylinder than it can naturally aspirate. It is to take advantage of the available power at its peek throughout combustion, while being delivered to another piston in a better position of the crank to deliver that power.
Current engine technology is putting around 60% of the energy from combustion in line with the crank and rod without delivering it anywhere, but into the assembly itself. Only when the crank gets maybe 30deg past top dead center is it able to impart a portion of what was available to the potentially restrained HP.
Until we see physical data from a working model, the concept is just that. Having an idea and making it work in the real world don't always pan out. This looks to offer big possibilities, but some of the claims do not match current fuel available as we know them.
Hopefully it doesn't end up in the same "top secret file" as the 100mpg carburator of yesteryear! [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
DC
The principle here is not to increase the volumetric efficiency by packing more mixture into the cylinder than it can naturally aspirate. It is to take advantage of the available power at its peek throughout combustion, while being delivered to another piston in a better position of the crank to deliver that power.
Current engine technology is putting around 60% of the energy from combustion in line with the crank and rod without delivering it anywhere, but into the assembly itself. Only when the crank gets maybe 30deg past top dead center is it able to impart a portion of what was available to the potentially restrained HP.
Until we see physical data from a working model, the concept is just that. Having an idea and making it work in the real world don't always pan out. This looks to offer big possibilities, but some of the claims do not match current fuel available as we know them.
Hopefully it doesn't end up in the same "top secret file" as the 100mpg carburator of yesteryear! [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
DC
Re: Great New IC Engine Idea
Based on the article, it sounds like the fried valve would not be an issue. Something similar shows up in US patent 6,216,649. The key is that as soon as the charging cylinder hits TDC, the spring loaded check valve to the power cylinder closes and acts like a standard intake valve. The firing occurs in the power cylinder and doesn't return to the charging cylinder if the engine is going to run at all. I can also say from experience that the air/fuel mixture going through the intake valve exerts a fairly strong cooling influence. As a result, you may see engines that backfire due to as leaking intake valve, but valve burning is almost always limited to the exhaust valve.
I can see that the greatest benefit is reduction in engine vibration since it fires on every revolution. Setting up counterweights in a 4-stroke is always a pain because a firing stroke has different dynamics than an intake stroke, The counterweight sizing includes determinations of forces from the vacuum of the intake stroke and the pressure of the power stroke. Counterweight size is a compromise to keep vibration for intake and power strokes the same. Being able to balance each activity separately should give a better final result.
Where it falls down is in the headspace above the charging cylinder for the volume of the transfer port and check valve. Inevitably that retained volume ends up flowing back to the charging cylinder and reducing the incoming air/fuel charge. I suppose if someone spent some time to minimize those volumes, the air fuel transfer efficiency could be improved. I suppose you could turbocharge.
The other weakness is the mass of all the stuff that has to move. I would expect accelleration to be lower than an equivalent power four stroke or two stroke engine.
Regardless of the rest, it still requires a timed exhaust valve and for best efficiency a timed intake valve in the charging cylinder. It should be possible to make the intake valve a reed type, so you could be able to get rid of some mass.
I can see that the greatest benefit is reduction in engine vibration since it fires on every revolution. Setting up counterweights in a 4-stroke is always a pain because a firing stroke has different dynamics than an intake stroke, The counterweight sizing includes determinations of forces from the vacuum of the intake stroke and the pressure of the power stroke. Counterweight size is a compromise to keep vibration for intake and power strokes the same. Being able to balance each activity separately should give a better final result.
Where it falls down is in the headspace above the charging cylinder for the volume of the transfer port and check valve. Inevitably that retained volume ends up flowing back to the charging cylinder and reducing the incoming air/fuel charge. I suppose if someone spent some time to minimize those volumes, the air fuel transfer efficiency could be improved. I suppose you could turbocharge.
The other weakness is the mass of all the stuff that has to move. I would expect accelleration to be lower than an equivalent power four stroke or two stroke engine.
Regardless of the rest, it still requires a timed exhaust valve and for best efficiency a timed intake valve in the charging cylinder. It should be possible to make the intake valve a reed type, so you could be able to get rid of some mass.
-
captainkirk
Re: Great New IC Engine Idea
Thanks for the reply Doug, there are a few things about the feel of this "project" that have a bad feel, not saying that it won't run but what are the losses because of the extra piston that isn't producing power? You could supercharge it by increasing the volume of the charge cylinder, but I have seen systems somewhat like this being sought in order to run two stroke engines without oil in the mixture, results were not as good as expected from my recollection. Here is a question for the group why not just use a roots type supercharger to prodide the compression then use it at any part of the cycle you wish? Nothings free as we all know, I'm not saying there are no gains to be had but the complexity involved here seems pretty high. Effectively you would be reducing an engine the size of a V8 into an effective inline four, and without the balancing effects of the other bank firing it would be a nighmare to keep smooth (possible to balance given the results of Ducati's Supermono balance system that could be employed here). On another note model makers can produce a running model to study for a reasonable sum why not even a small running model? Another thought how come strange "business" propositions seem to always be coming from Africa to my email? I think something doesn't feel right? But it is interesting to study
Re: Great New IC Engine Idea
It is an interesting idea, all be it fraught with unanswered questions.
I see their theory as using less fuel to produce the same output of a more substantial engine. You can scale the engines physical size and its throughput of fuel/air mixture, but conventional reciprocating assemblies still waste 60% of the power produced due to the process of linear to rotary motion elements. The applied charge forcing the piston down with the crank lets say at 1 O'clock verses at 3 O'clock is quite different in terms of mechanical advantage. Passing that charge to a piston timed in a better position on the crank to utilize that charge will waste less of the applied power during the maximum amount of linear to rotary motion.
The added friction, weight and volume differentials do look to be insurmountable conflicts in physics to get it to run with an increase that defies conventional engineering practices. Since it fires every revolution, I'd be inclined to think that the burn cycle may be shorter, but the consumption to keep the engine moving may make it a flat trade by the time power hits the wheels. It becomes a fine balance to their theory in claims in gains of power, not mentioning what it will absorb to make it functional.
Just the thought of one piston running constantly hot and dry was one of my questions too. I had stated in a previous post in this thread the use of a glow fuel platform to prove the theory. Much of that fuel is lubricant that goes out the exhaust.
Your roots blower question might be attempting to gain a something for nothing tail chasing circle. If you could create a 10:1 compression ratio at mid stroke as the piston is already traveling down, it might work. The volume above the piston may make that impossible as well. Not leaving enough power to run the blower in the process?
It is fun to ponder the possibilities along with the potential faults in a new concept. The only way to get those answers is to start making chips and see where the research leads you in a working model.
DC
I see their theory as using less fuel to produce the same output of a more substantial engine. You can scale the engines physical size and its throughput of fuel/air mixture, but conventional reciprocating assemblies still waste 60% of the power produced due to the process of linear to rotary motion elements. The applied charge forcing the piston down with the crank lets say at 1 O'clock verses at 3 O'clock is quite different in terms of mechanical advantage. Passing that charge to a piston timed in a better position on the crank to utilize that charge will waste less of the applied power during the maximum amount of linear to rotary motion.
The added friction, weight and volume differentials do look to be insurmountable conflicts in physics to get it to run with an increase that defies conventional engineering practices. Since it fires every revolution, I'd be inclined to think that the burn cycle may be shorter, but the consumption to keep the engine moving may make it a flat trade by the time power hits the wheels. It becomes a fine balance to their theory in claims in gains of power, not mentioning what it will absorb to make it functional.
Just the thought of one piston running constantly hot and dry was one of my questions too. I had stated in a previous post in this thread the use of a glow fuel platform to prove the theory. Much of that fuel is lubricant that goes out the exhaust.
Your roots blower question might be attempting to gain a something for nothing tail chasing circle. If you could create a 10:1 compression ratio at mid stroke as the piston is already traveling down, it might work. The volume above the piston may make that impossible as well. Not leaving enough power to run the blower in the process?
It is fun to ponder the possibilities along with the potential faults in a new concept. The only way to get those answers is to start making chips and see where the research leads you in a working model.
DC