New rotary engine design!

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roninsoldier83
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New rotary engine design!

Postby roninsoldier83 » Fri Jun 05, 2015 9:14

Has anyone seen this new rotary design? Check this out:
https://www.youtube.com/watch?v=0e785Yn ... Uw--Z49V5-

The engine above is a diesel (even though it appears to have spark plugs?!?). They're claiming up to 50% reduction in diesel fuel consumption while the motor is 75% smaller than similar power output diesels. Gasoline motors are a similar design but lower compression ratio. They're saying about a 20% decrease in fuel consumption and 30% smaller than a similar output traditional gasoline motor. They claim it will be scalable from 1 hp to 1,000 hp. They received $1m in funding from DARPA. Here's a few articles:

http://www.popularmechanics.com/militar ... -contract/
http://www.popularmechanics.com/cars/a8 ... -13817971/
http://newsoffice.mit.edu/2014/liquidpi ... ngine-1205

Quick diagram:
Image

In my opinion, its brilliant! They've inverted the idea of the traditional Wankel rotary! No more triangle in oval housing; I like the oval in the triangle housing idea! With 3 combustion chambers within one housing its no wonder the efficiency/size ratio is so high! Unfortunately, it doesn't look like you would be able to "stack" this design, so you're probably "stuck" with only 1 housing, but the one housing is essentially a 3 cylinder/housing design in a compact package!

I did a bit of reading about this design and it really is genius. No more apex seals on the edges of the rotor that need to be lubricated with injected/consumed oil; the apex seals in this design are stationary on the housing itself (on triangle edges/tips of the combution chambers from my estimation). This would essentially mean it wouldn't consume nearly as much oil as a Wankel rotary, and consequently, should reduce emissions (a long time sore spot with making the rotary emissions legal).

I'm curious to see how large this engine would be when scaled to around the ~300hp mark. I'm just sayin'.... Interesting that they're only really marketing it towards small appliances & military applications and not cars. I guess it makes sense though, as auto manufacturers are now leaning heavily towards making electric cars as the next wave of transportation. I'm also curious to see how robust this design is; specifically the apex seals, as they've seemingly been one of the primary limiting factors in high HP Wankels. Also curious about the solidity of the intake/exhaust ports within the rotors themselves. It's too bad this design wasn't invented 20+ years ago when the internal combustion engine was still fully reigning supreme... Either way, I really like this concept.

Dear Mazda: rotary powered sports cars are in your heritage and you have fairly deep pockets.... I'm just throwing that out there!

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GR-8
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Re: New rotary engine design!

Postby GR-8 » Mon Jun 08, 2015 9:14

That's an interesting design. Wonder what kind of seals it would require. Probably the standard side seals. And probably seals on the tips of each chamber. They would be stationary so that may aid in reliability. Anything on cooling. I would imagine it would get very hot with 3 combustion chambers in one housing. Its a very different concept. For each stroke/revolution it would combust 3 times like a winkle. It would be interesting if they could duplicate the other end for intake and exhaust and double the combustion per revolution.

I wonder if Mazda is still working development for the 16X. If they could make a 250ish WHP RX-X then I feel it could sell well. Power was probably the biggest thing that hurt the sales of the RX-8. As well as "Modability". Not sure how well the BRZ/FRS is doing but the demographic I see driving one is usually older women. Sitting in one it feels very cramped. I considered trading the NA 8 in on one but I couldn't see myself liking it more. Even if a WRX version did come out Id still stick with the 8.

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Re: New rotary engine design!

Postby roninsoldier83 » Mon Jun 08, 2015 9:14

That's a good point about trying to cool a housing with 3 combustion chambers. It would be interesting to see what a major auto manufacturer could do with it. I'm also curious to see how it would handle varying speeds (vs constant speeds for the applications they're working on).

Mazda recently said they're not making anymore rotaries. Their current chief stated the rotary isn't viable/profitable and they don't have any plans to make one in the future:
http://www.caradvice.com.au/318261/mazd ... ports-car/

It should probably be noted that since canceling the RX-8, Mazda's overall reliability ratings have shot through the roof. We all know they've been making reliable cars for years, but lots of rotary problems bring per capita reliability ratings down a peg or two. I imagine they're not too keen on bringing back a rotary to tarnish the glowing reliability ratings they've been receiving lately. They've also been marketing the Skyactiv fuel economy based tag pretty heavily as well, so the old gas guzzling Wankel rotary wouldn't exactly go with their new corporate image. :D

I've often debated the reasons why Mazda didn't sell more RX-8's.... I've come up with a few ideas on some of the reasons why:

-The lack of power/torque really turned a lot of people off who don't know much about cars.
-Dismal reliability ratings and countless engine blowing horror stories scare off a large portion of the consumer segment. If you start looking up consumer reviews for the RX-8, well, lets just say I've never seen a car with more motor blowing stories! Granted, quite a few of them are likely the owner's faults; but most consumers don't know that and don't care to find out. Hence why they have such low resale values.
-For the hardcore stat junkies there were other competitor cars that did things better than the 8: the 350Z and S2000 were both much faster (in a straight line) and the S2000 probably handled a little sharper. Both also have good reliability ratings and get better fuel economy. Hell, even Mazda's own econobox (MS3) was rated at being a faster and more efficient car than the 8, and it was cheaper to boot!
-Extremely poor fuel economy and it consumes oil by design haha!
-People who have been tuning cars for years generally have only a very limited amount of knowledge on the rotary, and most of what they know is negative (myself included!).

Me personally, I'm considering buying one... but I can definitely see a LOT of reasons why your average consumer would stay far far away from the 8!

IMO, in today's horsepower-war-laden market, I don't know if even 250whp would be enough to launch a halo sports car unless it was very light weight, or dirt cheap. I've read the BRZ/FRS aren't selling very well these days, even though all of the auto journalists sung their praises when they were first released.... Meanwhile, as the BRZ is collecting dust, Subaru can't hardly keep (268hp) WRX's in stock! The new 4-cylinder Mustang now has over 300hp and pretty much every souped up econobox is sporting 250+hp these days; cars starting in the low 20's.

Maybe you're right though, maybe 250whp would be enough; but the market is really going crazy for power these days! When the BASE Mustang & Camaro's are all offering 300+hp, with independent suspensions and available track packages, its a tough sell. Especially when the big brother's of those cars are offering 430+hp for around $30k (starting) and cars like the Charger/Challenger R/T Scat Pack are coming with 485hp for only $40k. Granted, those are a completely different market of cars, but I think people are coming to expect more and more power from cars these days.... but then again, this is the way Mazda has pretty much always handled business and I supposed its worked out alright thus far. :)

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Re: New rotary engine design!

Postby GR-8 » Wed Jun 10, 2015 9:14

Good points on the power a sports car would need today. 10yrs ago 250HP to the wheels would have been plenty but today more is expected. If/when the Speed3 and/or Speed6 ever comes back. They will have to be over 300BHP to be competitive and around 25-30k starting. You can pick up a Kia Optima SX turbo with 269hp/tq for around 30k with the non turbo starting around 22k. If you spent 30-35k on a sports car today you'd expect it to be more powerful than the optima and similar vehicles.

I think Mazda is in a good position to offer higher HP versions of the 3 and 6 under 30k. They start at 17k/19k for the 3.(4door/5door) and 21.5k for the 6. So a Speed Version could easily fall under 30k starting. I see so many Optima SX on the road and just wish Mazda would offer different power options alongside the SkyActive models. Everyone else offers different models and power options for their cars but Mazda only has 1\2 options for their entire lineup of vehicles. But I guess as long as they keep selling the SkyActive models there isn't real reason or urgency for them to offer more options.


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