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Mazda’s rotary engine in the age of the electric car

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Re: Mazda’s rotary engine in the age of the electric car

#171

Post by greggyb »

ggreer wrote: post #112
eggsboenk wrote: post #106

Earlier quoted context omitted.

The McMurtry Spéirling is claimed to be under 1000kg. A lightweight electric car may not be an oxymoron after all. Just some concessions to make.

The McMurtry Spéirling is not street legal and it costs $1 million.

The Bugatti Veyron launched in 2005 with 1K horsepower and cost > $1M. As of last year, you could get a Dodge Challenger with 1K horsepower for While it is not a guarantee, the innovations in today's supercars do tend to become much more common with time.

Re: Mazda’s rotary engine in the age of the electric car

#172

Post by bluedino »

coryrc wrote: post #28
sethhochberg wrote: post #16

Earlier quoted context omitted.

They have a pretty narrow power band (produce efficient max power at a small range of RPMs) which always somewhat limited their use for normal ICE cars, but is a pretty workable constraint for an electrical generator. So you have compact size, good power to weight ratio, and power limitations that don't really matter for range extender purposes. Lots of potential. I can't find the article right now, but I'd swear I r…

Then you may as well use a gas turbine, which is pretty much better in every way that matters for generating purposes.

Chrysler tried it in the 50's and 60's

https://en.m.wikipedia.org/wiki/Chrysler_Turbine_Car

The ideas and innovations back then seemed amazing

Re: Mazda’s rotary engine in the age of the electric car

#173

Post by willis936 »

ryukoposting wrote: post #141
486sx33 wrote: post #2

Does it produce more low end torque verses a traditional gasoline combustion engine? If not then why is it better suited for electrical generation? Is it more efficient with less load? The article mostly makes it sound like Mazda just loves the wankle and wants to find any possibly way to bring it back - even though it has “high” emissions… so coupling it with a hybrid electric motor makes it happen.. That can’t be t…

It has nothing to do with sentimentality. Wankels have tremendous power-to-weight and power-to-size ratios. Their main problem is reliability. The generally accepted solution to improve rotary engine reliability (oil injection) results in poor emissions. The wide, flat-ish combustion chamber doesn't help the emissions problem, either. The Wankel is at its most efficient and its most reliable when operating at a const…

Reliability is something easily discounted because the data to characterize it is much more difficult to capture than performance data. In most applications you can work around this with redundancies and diverse technologies, but no one makes a fault tolerant powertrain due to cost.

I don't think there's a good reason to keep pushing down deadend reliability paths. We should be responding to our hard earned decades of learning and be pressing advantages. Not every novel and viable solution ends up being an enhancement.

Re: Mazda’s rotary engine in the age of the electric car

#174

Post by AtlasBarfed »

ryukoposting wrote: post #141
486sx33 wrote: post #2

Does it produce more low end torque verses a traditional gasoline combustion engine? If not then why is it better suited for electrical generation? Is it more efficient with less load? The article mostly makes it sound like Mazda just loves the wankle and wants to find any possibly way to bring it back - even though it has “high” emissions… so coupling it with a hybrid electric motor makes it happen.. That can’t be t…

It has nothing to do with sentimentality. Wankels have tremendous power-to-weight and power-to-size ratios. Their main problem is reliability. The generally accepted solution to improve rotary engine reliability (oil injection) results in poor emissions. The wide, flat-ish combustion chamber doesn't help the emissions problem, either. The Wankel is at its most efficient and its most reliable when operating at a const…

What happened to the inside out rotary that was supposed to be extremely compact and would enable cheaper PHEVs? IIRC the patents were about 5 years ago.

Re: Mazda’s rotary engine in the age of the electric car

#175

Post by 14 »

willis936 wrote: post #173
ryukoposting wrote: post #141

Earlier quoted context omitted.

It has nothing to do with sentimentality. Wankels have tremendous power-to-weight and power-to-size ratios. Their main problem is reliability. The generally accepted solution to improve rotary engine reliability (oil injection) results in poor emissions. The wide, flat-ish combustion chamber doesn't help the emissions problem, either. The Wankel is at its most efficient and its most reliable when operating at a const…

Reliability is something easily discounted because the data to characterize it is much more difficult to capture than performance data. In most applications you can work around this with redundancies and diverse technologies, but no one makes a fault tolerant powertrain due to cost. I don't think there's a good reason to keep pushing down deadend reliability paths. We should be responding to our hard earned decades o…

Except in Mazdas case the data was there to characterize it. They were notorious for failing very early and suffered bad seals around the rotary shaft. This has been well known for a long time. Many Rx owners knew ride it for 100k miles then sell it before it is too late.

Re: Mazda’s rotary engine in the age of the electric car

#177

Post by pmsh »

dragontamer wrote: post #47

A good article. It barely addresses the elephant in the room however: The Toyota Prius and its Atkinson engine. The Atkinson engine is 99% the same as a regular engine (aka: Otto cycle), except the timing is different. Instead of closing the valves when the piston+cylinder is full of gasoline+air mix... the Atkinson engine waits a bit and "leaks" some gasoline+air back out before closing the intake valve, effectively…

If the engines are direct injected rather than port injected, they can just delay fuel injection until the intake valve is closed, and no fuel should be pushed back into the intake manifold.

I have read that modern Toyota engines use both port and direct injection, but am not sure what the Prius does.

Re: Mazda’s rotary engine in the age of the electric car

#178

Post by Retric »

14 wrote: post #175
willis936 wrote: post #173

Earlier quoted context omitted.

Reliability is something easily discounted because the data to characterize it is much more difficult to capture than performance data. In most applications you can work around this with redundancies and diverse technologies, but no one makes a fault tolerant powertrain due to cost. I don't think there's a good reason to keep pushing down deadend reliability paths. We should be responding to our hard earned decades o…

Except in Mazdas case the data was there to characterize it. They were notorious for failing very early and suffered bad seals around the rotary shaft. This has been well known for a long time. Many Rx owners knew ride it for 100k miles then sell it before it is too late.

That rate isn’t a deal killer for a plug in hybrid. The engine might see ~1/4th the ware per mile spending the vast majority of its time off.

Meanwhile hybrids really want a small and lightweight engine because of all the extra equipment.

Re: Mazda’s rotary engine in the age of the electric car

#179

Post by wkat4242 »

One of the cool things about this engine is that it can run on hydrogen with minimal modifications. Not sure if the article mentions this, I don't have time to read it now. But that could make it more interesting when renewable hydrogen becomes common (right now it's not)

Re: Mazda’s rotary engine in the age of the electric car

#180

Post by giobox »

ggreer wrote: post #155
discreteevent wrote: post #120

Earlier quoted context omitted.

“Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere.” - Colin Chapman (Lotus)

I agree with the adage, but brute force seems to win in this specific case. Even though it's the lightest model made, my Miata only gets 0.82g on the skidpad.[1] The Model 3 Performance gets 0.96g thanks to its wide tires, which are needed to transfer all its power to the asphalt.[2] This difference isn't just due to the 1990 Miata's older suspension and tire technology. Even the latest Miatas only get 0.90g of later…

> I agree with the adage, but brute force seems to win in this specific case. Even though it's the lightest model made, my Miata only gets 0.82g on the skidpad

The current ND2 (2019+) Miata regularly pulls ~0.95 stock in magazine tests, almost identical to your model 3 Performance number.

> https://www.motortrend.com/reviews/2019-mazda-mx-5-miata-clu...

You can exceed 0.95 and get ~1 on an ND Miata with slightly wider than OEM tires (still on stock rims) and a little more negative camber, which is widely done to the car by the enthusiast community. Similarly, you can get more out of your very own NA (1990) Miata with simple tire/alignment changes, even more with cheap new sway bars or springs etc.

> https://help.flyinmiata.com/align-your-suspension-chakras-By...

The ND2 is a ~1070kg car.

To use a more fitting Lotus example here, the ~900kg Lotus Elise (50% of the weight of the Model 3 Performance) pulls 1g when tested by Car and Driver:

> https://www.caranddriver.com/reviews/a15146116/2007-lotus-el...

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