Mazda says they are not through with the Rotary

http://www.autocar.co.uk/car-news/moscow-motor-show-2012/moscow-motor-show-mazda-commits-rotary

"Speaking at the Moscow motor show, Mazda boss Takashi Yamanouchi has reaffirmed the company's commitment to the rotary engine. He revealed plans to launch a new range extended car using the engine next year, and to keep developing rotary applications for use in future sports cars."

I'm guessing the "range extended" car means they'll have a small rotary powering the generator.

"We are still learning," he said. "the rotary has very good dynamic performance, but if you accelerate and brake a lot there are efficiency disadvantages. The range extender overcomes that. We can keep it spinning at it's most efficient 2000rpm while also taking advantage of it's size."

Audi was planning something similar. 500cc-ish Wankel (cheater measurement, I assume - same real volume as 1000cc piston 4-stroke) that could fit in a box around 9-10" on a side, cooled/preheated by the traction motor's coolant, and mounted under the trunk for minimal NVH.

Rotaries are awesome for fuel efficiency under full load. This is totally their calling.

The crankshaft in my dad's 7.3L diesel V8 is rotary... does that count? He only has 434K miles on it and it has towed over 18,000 lbs consistently for 13 years with only $65 in failures.

Did I mention it makes 653 hp at the wheels?

Knurled wrote: Rotaries are awesome for fuel efficiency under full load. This is totally their calling.

But the untold millions of dollars have already been invested in making piston engines more efficient that rotaries so why throw even more money at a rotary?

Not saying it's not a good design, just saying the reciprocating engine has had more development and is already at a more advanced state. It's at a better stage to improve it further.

I'll go even further.

Gas turbines are capable of running at 100% power output for thousands of hours. Why not use one to run a generator? Oh, wait, that's right, they do that already.

Why not just scale it down?

Trans_Maro wrote: I'll go even further. Gas turbines are capable of running at 100% power output for thousands of hours. Why not use one to run a generator? Oh, wait, that's right, they do that already. Why not just scale it down?

Probably price. A rotary may be somewhat more expensive than a regular piston engine to manufacture, but a gas turbine is dramatically more expensive to make. After watching videos of 5 axis CNC mills making the blades for them, it's no wonder why.

Glad to see the rotary still has some life in it. They're so smooth and high revving. If the fuel efficiency were better, I probably would have bought an RX-8, but in 2007 I was driving 60 miles a day with gas at $4 / gal. The poor mileage of a rotary was something beyond justification for me.

In reply to Trans_Maro:

Love me some turbines.

Trans_Maro wrote: But the untold millions of dollars have already been invested in making piston engines more efficient that rotaries so why throw even more money at a rotary? Not saying it's not a good design, just saying the reciprocating engine has had more development and is already at a more advanced state. It's at a better stage to improve it further.

I was talking with someone today who was pleased as punch that the Volt was stopping production.

Basically, he was pissed off at all of this hybrid and electric car nonsense when they should be using this R&D money for finding better ways to drill for oil.

I was completely at a loss for words, so I shrugged and walked away.

Knurled wrote:

Trans_Maro wrote: But the untold millions of dollars have already been invested in making piston engines more efficient that rotaries so why throw even more money at a rotary? Not saying it's not a good design, just saying the reciprocating engine has had more development and is already at a more advanced state. It's at a better stage to improve it further.

I was talking with someone today who was pleased as punch that the Volt was stopping production. Basically, he was pissed off at all of this hybrid and electric car nonsense when they should be using this R&D money for finding better ways to drill for oil. I was completely at a loss for words, so I shrugged and walked away.

Exactly. We advance by constantly exploring and improving.

You know they aren't going to stop, they only take breaks. Why spend decades of money on tooling and just give up? It probably costs them more to keep it then to not use it. You can bolt up a 2011 rx8 manual transmission to a 1979 13b, bell housing/starter pattern is the same (you just need to use a turbo FC or FD/rx8 clutch)

Very interchangeable

besides have we forgotten the audi A1 E-tron they were in conjunction with? Hydrogen RE dual fuel system the 16X http://www.mazda.com/mazdaspirit/rotary/16x/

Read something on the rotary this morning. Mazda plans on using the Rotary to power a generator and charge the batteries on an extended range electric vehicle. Link to Rotary Article

MBA uses a rotary motor in the collision mitigation system when it predicts a crash, IE uses them to retract the seat belts as a single charge use.

also more info on the hybrid fuel hybrid electric rotary engine range extender insert more car adjectives here mobile.

http://www.gizmag.com/mazda-hybrid-rotary-hydrogen-premacy-re/11350/

You guys think I'm bashing the rotary, hybrids and new product development but I'm not.

Did you read the article? Where it says this:

"We are still learning," he said. "the rotary has very good dynamic performance, but if you accelerate and brake a lot there are efficiency disadvantages. The range extender overcomes that. We can keep it spinning at it's most efficient 2000rpm while also taking advantage of it's size."

If they're looking at running a generator (range extender) then they will need an engine that runs at a constant RPM.

A gas turbine is ideal for this, it can be sized so that it's output at 100% torque is everything that the generator needs and no more. It can run at 100% torque for thousands of hours with little to no maintenance. They can also burn any combustible fuel you can feed them (Hydrogen maybe?)

Try running a piston or rotary engine at 100% output for a long time and see what happens.

As for scale, check out how an aircraft APU operates. It's pretty much the same idea and in a nice small package.

As for pistons vs rotaries, I know it's edgy and cool to be different but given the numbers that Mazda is getting from the Skyactive engines, they need to realise that the rotary may be an evolutionary dead-end as far as powering an automobile goes. There just might be a reason that no other manufacturers are using them.

Also, there are investors and a BOD to answer to. The money has already been spent getting piston engines to this level, what if they spend more cash on rotaries and they only end up as efficient or worse than technology they already have. There's only a finite amount of energy in a given amount of fuel and they're doing pretty damn well with DI piston engines.

Just my opinion, take it any way you want.

Shawn

BAMF wrote:

Trans_Maro wrote: I'll go even further. Gas turbines are capable of running at 100% power output for thousands of hours. Why not use one to run a generator? Oh, wait, that's right, they do that already. Why not just scale it down?

Probably price. A rotary may be somewhat more expensive than a regular piston engine to manufacture, but a gas turbine is dramatically more expensive to make. After watching videos of 5 axis CNC mills making the blades for them, it's no wonder why.

Eh, a lot of stuff in aerospace is low-volume, obscenely high tolerance, expensive, and custom. I have no doubt that if a gas turbine was produced for an APU-like constant RPM automotive engine, it could be made extremely cheap.

A small rotary could be made REALLY cheap though. At peak BSFC and high-load it could very well offer piston-like constant RPM fuel usage in a small, light, cheap package.

Anyone have a BSFC chart for a sky-activ engine? From my reading, most modern piston engine peak BSFCs are pretty close... where the technology comes into play is assisting with the off-peak consumption (95% of driving, and where the rotary suffers). The "sweet spot" is getting larger and larger with modern engines, and more advanced power-trains to keep it in the sweet spot have a huge impact. But, for a constant RPM/Load, no tweaking of the off-peak usage is necessary, nor is any transmission/powertrain control necessary to keep it where it should be.

I would think the easy-button option for an auto manufacturer would be a large single cylinder piston engine. Very efficient, very cheap to manufacture, but unfortunately sound crappy (to consumers), and have terrible NVH.

ProDarwin wrote: Eh, a lot of stuff in aerospace is low-volume, obscenely high tolerance, expensive, and custom. I have no doubt that if a gas turbine was produced for an APU-like constant RPM automotive engine, it could be made extremely cheap.

Exactly.

When you consider that a production run of 2000 is high for aircraft, what happens when you amortise that development cost over 100,000 automobiles?

ProDarwin wrote: A small rotary could be made REALLY cheap though. At peak BSFC and high-load it could very well offer piston-like constant RPM fuel usage in a small, light, cheap package.

Rotary BSFC is .40-.45 under max load when optimized for that loading. It just sucks at idle and cruise and other low-load work, especially when you have to make necessary compromises for that.

People go on about 787B this and that, but it needs to be said that LeMans was a race involving fuel efficiency - they only had so much fuel to use, so thirsty engines aren't such a good idea.

Strangely enough, fuel efficiency was one of the reasons the 787B won at LeMans. The R26B got better mileage than the Ferrari and Jag V12's.