I think this is a really novel design and I love that people are thinking outside the box. The folks at NASA were also sufficiently impressed as to give it an award. I have some doubts as to how viable it is, however.
First of all, I think it will suffer the same drawbacks as a Wankel engine:
Sealing: Rotary engines historically have had problems with the apex seal failing fairly early. They’re also not cheap. A cursory search shows Mazda apex seals running over $200 (then you also need to buy side seals and corner seals). Compare that to $40-$80 for a set of piston rings for a Chevy 350.
Inefficient combustion: Due to the combustion chamber shape, I’m guessing that flame-front propagation won’t be ideal and it’ll result in a lot of NO[sub]2[/sub] and unburned hydrocarbons.
A couple of other things I noticed:
High compression ratio: Using the highly technical process of measuring screenshots, I calculated a very rough compression ratio of 23:1. This is way too high for pump gasoline. I think you can use E85 at that pressure, but I’m not sure. The website mentions spark plugs, so I’m assuming it’s not supposed to run on diesel. I submit that I may be wrong on the compression ratio - I didn’t check my work.
It looks too delicate: Yeah, I know. This isn’t exactly scientific, but this machine looks more like a fine watch than something designed to harness the energy from controlled explosions.
The first thing I noticed is that all the images on their site are drawings. In other words, no actual engines. It’s fairly easy to claim that one can “ramp up [the efficiency of an IC engine] to 50 percent by shifting from a piston-driven engine design to an ‘internally radiating impulse structure’.” It’s quite another thing to do it. Not that I think they’re being dishonest, I should add; it’s just that real systems always have more friction and blowby and heat losses than one optimistically projects.
This relates directly to your comment that “it looks too delicate.” I suspect a real embodiment of this engine will require larger bearings and stiffer iris sections than they show in order to accurately position the iris structure and keep it robust. In addition, they’ll need substantial seals. The added mass and friction will reduce efficiency.
The second thing I notice is their claim that the IRIS efficiency increase is due to increasing the "productive surface area. To wit: it “addresses a primary cause of inefficiency in ICEs by expanding in diameter rather than length, increasing the ratio of ‘productive surface area’ (area that does work) to ‘passive surface area’ (area that generates waste heat).” That is, to be blunt, way over-simplified. Minimizing heat loss is an important consideration, but this is not an either-or thing: heat is lost through pistons or irising structures also.
The third thing I notice is that this appears to be a two-stroke. That’s cool and all, but then in the next breath they say “the design utilizes an innovative valve/vent system that also enables the engine to breathe far more effectively than traditional piston-in-cylinder mechanisms.” How exactly does this work? Because it seems like the “innovative valve/vent system” is more important to overall efficiency than the “internally radiating impulse structure”.
The fourth thing I notice (like you did) is that this seems to have a high compression ratio, or at least a high expansion ratio (note: “gasses… expand farther before their productive utility is overwhelmed by friction and other losses.”). Upping the compression ratio is certainly a good way to improve efficiency, but it’s hardly unique to “internally radiating impulse structures”.
So, bottom line: high-CR two-stroke with radial sealing issues and unknown additional losses.
I’d also like to see how they convert the back-and-forth motion of the iris panels to smooth rotational motion. Camshafts are a pretty mature technology, but it looks to me like you’d need something new for this.
Meh. Looks like all the face sealing problems of a Wankel (with tappet valves on one of the faces to add to the joy) and only twice as many apexs to seal…what could possibly go wrong?
Chronos: From the looks of the crank assembly, each “chordon” is attached to a shaft which in turn has an individual crank arm attached to it. The end of this crank arm approximates the up-down motion of a piston. A connecting rod is pinned to the end of the crank arm and drives a shaft much like a normal piston engine.
This does bring up a good question though: Is the arc movement of the chordon crank more inefficient than the pure linear motion of a piston?
Kevbo: I laughed. And “face” is the name for those seals. Thanks for reminding me! I called 'em side seals.
The second video shows the mechanism: each iris panel is connected to a rocker, which is in turn joined to a standard-looking standard con rod and crankshaft. Kinematically sound, I think, but an assload of bearings for a single-cylinder engine.
I don’t get excited about these things anymore until somebody actually builds one that burns fuel and runs for a while. Like this guy’s engine, which I think is actually rather neat:
Thanks Matt…
One Greek inventor also was fond of this solution and did me such a nice animation.
But even I don’t know the extent to which this programme made. http://www.new4stroke.com/new4strokegreek2.gif
I wouldn’t be surprised if this concept works; there are a number of other novel designs (rotary vane, Rand Cam) that have been developed.
the devil in the details is actually taking it to the point where you can manufacture a lot of them, and have them last relatively problem-free for 150,000 miles. That’s the big part, new designs are competing with the piston engine’s 100 years of refinement.
I’m no engineer, but there seems to be waaay too much going on there to be efficient. You’ve got the “chordons”, attached to very very long shafts, attached to a connecting rod, attached to another connecting rod, attached to a crank. Thats a ton of reciprocating mass all moving in sync, lots of bearings and lots of seals. Most of those parts are transmitting power via wierd angles that look very prone to twisting and bending. If this is meant to be a single, its going to need a massive flywheel to give it any hope of running smoothly.
They seem to have taken the worst of 3 different types of engines. They combined the inefficiencies of a two stroke, added the sealing problems of a rotary, and made it as complicated as a multicylinder.
As you are an engineer, you should not speak on topics enginering. 'Cause you don’t know even the basics of enginering . Talking, for example, that big weight of reciprocating mass back.Not true, but unless you do not have noticed that the bottom of the shaft (with four piston) rotates teh two times slower, so the force from the weight of the reciprocating mass callback is 4 times smaller, because it is the square of the speed trap. But can this pistons comes 60% capacity cylinder, which also does not have noticed. , so minus four times force from reciprocating mass feedback.
One of the physicists of the Swiss so nicely wrote:
Daniel , CH physicist elegant describe efficiency:
Weight popped 75 mm 1000 G
weight piston & rod 76.5 mm 850 G
Besides, with the second prototype, the curiosity I and i want to say that this is the best acting I have seen how the engine in my life …
Although the issue that could that could not necessarily so as to be
But is the best … However, I have a little bit of luck…
You will find that such admonitions carry little weight on this board. You are quite welcome to debunk other posters suppositions and incorrect information, but attempting to silence other posters is not cool.
And all I can say about the engine is that if it’s rotary…, Well, if Mazda couldn’t get everything working at maximum efficiency given all the time and money they’ve sunk into them, I doubt someone with mere animations can prove otherwise.
On his qualifications he lists that he was a sound engineer that traveled with many famous Polish bands, was a Rally driver, and produced dimmer switches.
His first prototype was made in 1978.
Lots of diagrams, drawings and black-and-white photos of engine parts, but no live action movies of engine working.
Is there an estimated date for when we will get to see this thing in action?
Daily, for 3 years I took the engine. i.e. the 1000 days. How can earn a good mechanic for 1 day?
So much prototype this. But somehow it does not want anyone to watch,Despite the fact that each invite.
Could it be that nobody wanted to see how to work with real four stroke engine . ??
The easiest way is to write something on the forum, maybe not so …
Besides, how do you know that I’m not the next prototype? Not everything can be improved and I gotta publish …
Mazda wants to spend money on as Sisyphys the work, let the issue … at least is to advertisement, which you quote someone else 's.
And just such a figure to know that this Sisyphys work …
I think that the Stephenson engine was enough for understanding the value that this animation.
