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The only ICE advancement that really seems interesting to me is adding an extra cycle to inject distilled water into the cylinder for an extra power stroke. The idea being that the heat from the prior explosive power stroke is used to turn the water into steam. Now you're using wasted heat energy and removing the need for cooling components.
Earlier quoted context omitted.
215hp out of a 3 litre is shockingly low except for a naturally aspirated carburator engine from the 80's. For example the 2 litre 2015 Mondeo Turbodiesel gets 210bhp. The article is interesting but reads like a marketing release, the weight saving is the interesting take away I think if reliability matches a modern diesel.
I do agree with you but a turbo diesel isn't a valid comparison because it is: 1) turbo charged 2) diesel fueled An inter-cooled turbocharger setup on this engine would likely net an additional 100 HP without much issue (presuming the sealing issues aren't horrific). Generally 100 HP per litre of displacement is the gold standard for naturally aspirated engines (see Ferrari).
The turbo is irrelevant though, the IC has a turbo, they work and are reliable the rotating engine doesn't but that doesn't rule out a basis for comparison.
It comes down to fuel efficiency, emissions, maintenance and cost and I can't see this engine winning (for cars).
No mention of meeting fuel economy and emissions requirements. Both of those are big topics that engine builders have to consider, with the 35mpg fleet-wide average that cars sold in the US must meet in about a decade. Having grown up in an age filled with car exhaust from carburated engines, I don't miss it a bit -- I like having clean air. One of the comments to the article mentioned the difficulty in keeping high-…
Earlier quoted context omitted.
As an RX8 owner (and enthusiast), I can tell you Wankel Rotaries aren't categorically better, or worse. They have strengths and weaknesses: - The vast majority of rotaries will need a full rebuild before 100k - worse - They rev to 10,000 RPM with an unbelievably smooth power delivery - better - I'm lucky to see 22 mpg - worse - The engine is so small and light that the RX8 has perfect 50/50 weight distribution - bett…
Learned stick on my second gen RX-7... -Almost no torque at low rpm - worse -Easy to flood, then once flooded major work - worse -Feed it a quart of oil every 1,000 miles - worse
Duke Engines have been around since 1993, and built their first prototype in 1996[1]. Axial engines themselves date back to 1911; Their practical use is limited to torpedoes, where the cylindrical form-factor is an advantage.
Axial engines have inherently high reciprocating mass compared to conventional piston engines, which is a catastrophic flaw in a performance engine design. Higher reciprocating mass increases inertia (reducing throttle response) and increases the forces at the end of the stroke (reducing maximum RPM). They offer no meaningful advantages in terms of fuel efficiency, and are likely to be less efficient in many applications due to the difficulty of implementing existing efficiency technologies (VVT&L, valve deactivation etc)
Both the current Duke engine and their hypothesised next-generation engine offers poorer specific power than current naturally-aspirated designs. The cylindrical form-factor is more difficult to package than a traditional piston engine; Camshafts offer enormous flexibility in terms of layout, allowing the engine to be squeezed into a multitude of shapes and sizes. Axial engines are inherently balanced, but balance is practically a non-issue in modern engines, even for layouts with very poor inherent balance.
No mention of meeting fuel economy and emissions requirements. Both of those are big topics that engine builders have to consider, with the 35mpg fleet-wide average that cars sold in the US must meet in about a decade. Having grown up in an age filled with car exhaust from carburated engines, I don't miss it a bit -- I like having clean air. One of the comments to the article mentioned the difficulty in keeping high-…
But not all engines go in cars. Might be a nice one for aviation--though aviation engines are maybe even more handicapped against change than those in automobiles. The experimental aircraft market ain't that big. Other markets where Rotax lives might like it; pumps and such.
Anyway, that's probably another one of the reasons they're not expecting automotive applications in the first generation.
This isn't a new engine, it isn't a new idea, and it isn't a particularly good idea. Duke Engines have been around since 1993, and built their first prototype in 1996[1]. Axial engines themselves date back to 1911; Their practical use is limited to torpedoes, where the cylindrical form-factor is an advantage. Axial engines have inherently high reciprocating mass compared to conventional piston engines, which is a cat…
This isn't a new engine, it isn't a new idea, and it isn't a particularly good idea. Duke Engines have been around since 1993, and built their first prototype in 1996[1]. Axial engines themselves date back to 1911; Their practical use is limited to torpedoes, where the cylindrical form-factor is an advantage. Axial engines have inherently high reciprocating mass compared to conventional piston engines, which is a cat…
Coupled to a automatic or CVT gearbox it may get around this problem.
I do think that your point about it lacking VVTL is somewhat amusing though.
The only ICE advancement that really seems interesting to me is adding an extra cycle to inject distilled water into the cylinder for an extra power stroke. The idea being that the heat from the prior explosive power stroke is used to turn the water into steam. Now you're using wasted heat energy and removing the need for cooling components.
http://sandbox.mikepurvis.com/design/engine.svg
Completely impractical, but an interesting experiment. There's some more general info on Wikipedia: http://en.wikipedia.org/wiki/Six-stroke_engine
"Duke Engines' 3-liter, five cylinder test mule is already making a healthy 215 horsepower and 250 lb-ft of torque at 4,500rpm – slightly outperforming two conventional 3 liter reference engines that weigh nearly 20 percent more and are nearly three times as big for shipping purposes." Seems convenient to use a pretty lame reference engine to make yourself look good. 3 liter engines have made near 1000HP for years no…
How about hp per pound? Isn't that the advantage of this thing?
