Mazda's RX Vision with rotary engine won't happen

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The RX Vision, though, is a pipe dream. Mazda is smart to keep the rotary dream alive. It's smart to keep developing it in back rooms and to keep the idea on the public's mind.

But the RX Vision is just a design study. And there are some harsh realities about rotary engine emissions and fuel economy standards that are difficult for modern piston engines to achieve without expensive componentry. Emissions and fuel economy are both bugbears of the rotary


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All this is meant to put Mazda's recent comments to Top Gear in context. Mazda's design director, Kevin Rice, spoke to TG at the Concorso d'Eleganza Villa D'Este, and was waving Mazda's rotary flag quite enthusiastically. "In the back rooms at Mazda, we're still developing it," Rice said, "and when the world's ready to buy another rotary, we'll be ready to provide it."

I'd like that to be a comforting statement, but given the realities of fuel economy and emissions regulations and Mazda's position in the market, it seems like a hollow platitude. "When the world's ready" is just another way of saying "when we solve the fundamental issues with this engine layout, and there's an unambiguous market study that shows we can build these cars and make a profit, we'll consider it."


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http://www.autoblog.com/2016/05/24/mazda-rx-vision-rotary-production-chance-opinion/#slide-3679986

Likes most concept vehicles, the RX Vision has very high belt-line, very narrow windows and very large wheels(25 inches ?) with rubber-band tires.
 
They're doomed to fail with the Wankel until they get the compression ratio up and the combustion chamber surface to volume ratio down.
Seems like some really smart Americans developed a direct injection Wankel 40 years ago, give or take a decade.
 
Originally Posted By: A_Harman
They're doomed to fail with the Wankel until they get the compression ratio up and the combustion chamber surface to volume ratio down.

And they'd need to get rid of that square-cornered combustion chamber.

Those little corners are Mojave-desert vast, when it comes to HC. With HC allowable-limits now at electron-microscope levels, you can't have Mojave deserts. This ain't 1974 anymore.
 
Direct injection would put a lot of the emissions and fuel economy challenges to bed.

Insulation coatings on the rotors would put a lot of the thermal efficiency issues to bed as well.

The rest would have to be cleaned up in the exhaust with some serious after-treatment.
 
Originally Posted By: DoubleWasp
Direct injection would put a lot of the emissions and fuel economy challenges to bed.

Insulation coatings on the rotors would put a lot of the thermal efficiency issues to bed as well.

The rest would have to be cleaned up in the exhaust with some serious after-treatment.


There is still the problem of engine longevity as well. The Wankel does not live as long without a rebuild as a well built piston engine.
 
Dunno. I got 161K miles out of mine before it was destroyed in an accident, and it was a turbo, no less.

13B-REW engines didn't last, for reasons not having to do with the engine itself but rather what was attached to them.

The rest typically died from poor maintenance practices or abuse. Rotary engines are extremely unforgiving to either one.

Still, it's the least of concerns. Most cars these days are pretty much impossible to own outside of warranty. Some are no-good pieces of garbage even before that point.
 
I always thought that GDI would solve the smog problem with rotary engines.

I also thought that making a diesel rotary engine would be a good idea, but that was back when having an EGR valve and DOC was enough to make a diesel meet California smog.
 
Consider the amount of money and time that has been invested in Otto and Diesel cycle engines compared to one company trying to keep Wankel alive. If the Wankel had had the same resources thrown at it you can bet it'd be a whole lot cleaner and more efficient by now.

Originally Posted By: OneEyeJack
The 4-cycle engine with poppet valves is a tough act to follow.

Yes, but only because it is so entrenched. It is fundamentally flawed in efficiency terms, only making power every 4th stroke. And it needs a lot of carefully-timed moving parts to do this.

Originally Posted By: Brybo86
So what who cares about a rotary? Make that thing with a direct injected turbo inline 6!

I'll take it! That car is beautiful!

Which misses the point. The car looks like that because the engine can be so powerful for such a small physical size. If you start putting big, tall, long engines in it then the whole profile of the car will change to fit the engine in.
 
The long, skinny combustion chamber and the poor expansion ratio of the rotary doom it. Full stop. There is too much quenching of the flame front and a relatively huge crevice volume both of which are horrid for emissions. Too much heat escapes out the exhaust which is horrid for fuel economy. As was already mentioned direct injection would help, but DI is really an implementation of stratified charge and that's been done by Curtis Wright and John Deere with the rotary.

http://magazines.marinelink.com/Magazine...-engines-203518

30 years later and what do we have? Reciprocating engines.
 
Mazda doesn't even need to make a car , just supply the latest and greatest as a bolt on affair on all miata (aka mx-5)and let people handle the rest.
 
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