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“Inside-out Wankel” rotary engine delivers 5X the power of a diesel

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Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#41

Post by tromp »

bmelton wrote: post #36
andy_ppp wrote: post #22

I'm surprised the air intake isn't more aerodynamic, more like a fan blade to compress the air into the engine? Could this engine be fitted inside the rear wheel to save space and weight as well?

That's a really good idea. Mazda is doing something that I think is fairly novel, which is almost exactly what you've described. They've scaled down the rotary engine from their RX cars to a single-rotor and put it into their new EV (almost tucked into the front wheel well,) and letting it act as a 70ish horsepower generator for the otherwise battery-powered car to extend range.

Presumably this new model: https://www.greencarreports.com/news/1138444_mazda-mx-30-r-e...

Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#42

Post by seabird »

93po wrote: post #30
shadycuz wrote: post #21

Earlier quoted context omitted.

The engine is the size of a push mower. > XTS-210 is about the size of a basketball, weighs in at 19 kg (42 lb), and displaces 210 cc. So you are talking about a 26HP lawn mower. While the Camry might make more power at its normal size. It would not if you scaled it down to the size of a basketball. I'm guessing it would make 1-3HP at that size.

A Traxxas 5407 TRX 3.3 engine used in RC cars makes 1.42 horsepower, weighs 305 grams, and fits in the palm of your hand. This is 1hp per 0.46 pounds of engine weight, nearly three times better than the camry engine. Granted an RC engine runs on a mixture of fuel and nitromethane, and doesn't have any reasonable durability compare to a Camry engine. But it also only costs $200.

You can't just make the Traxxas 18x bigger and get linear performance improvement. Trying to compare power/weight between engines with radically different weight constraints is silly.

Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#43

Post by cjbgkagh »

93po wrote: post #30
shadycuz wrote: post #21

Earlier quoted context omitted.

The engine is the size of a push mower. > XTS-210 is about the size of a basketball, weighs in at 19 kg (42 lb), and displaces 210 cc. So you are talking about a 26HP lawn mower. While the Camry might make more power at its normal size. It would not if you scaled it down to the size of a basketball. I'm guessing it would make 1-3HP at that size.

A Traxxas 5407 TRX 3.3 engine used in RC cars makes 1.42 horsepower, weighs 305 grams, and fits in the palm of your hand. This is 1hp per 0.46 pounds of engine weight, nearly three times better than the camry engine. Granted an RC engine runs on a mixture of fuel and nitromethane, and doesn't have any reasonable durability compare to a Camry engine. But it also only costs $200.

I've read about a lot of people complaining about the difficulty of getting the mixture right, perhaps that might be a show stopper for a UAV that must reliably work unattended for a long time. Though the military should also be able to get such mixtures down to a science - so I don't know.

Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#44

Post by digdugdirk »

bmelton wrote: post #36
andy_ppp wrote: post #22

I'm surprised the air intake isn't more aerodynamic, more like a fan blade to compress the air into the engine? Could this engine be fitted inside the rear wheel to save space and weight as well?

That's a really good idea. Mazda is doing something that I think is fairly novel, which is almost exactly what you've described. They've scaled down the rotary engine from their RX cars to a single-rotor and put it into their new EV (almost tucked into the front wheel well,) and letting it act as a 70ish horsepower generator for the otherwise battery-powered car to extend range.

Mazda really seems like the only company innovating in the ICE space (this, wankel rotary engines, skyactive engines) and their cars look damn good these days too.

On top of that, they make fun cars. With buttons and knobs on the dash!

I'm glad they're still around doing their thing.

Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#45

Post by dingaling »

spydum wrote: post #39

I suspect a lot of folks confusion on how this works is better explained by this from warped perception (first place I heard of this inverted rotary): https://m.youtube.com/watch?v=jLtyNtf9_ew&t=10s

Confusion is also possibly due to misuse of the term 'rotary'. A true rotary engine turns on its crankshaft. The Wankel is a rotating-sleeve-valve engine.

Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#46

Post by CocaKoala »

digdugdirk wrote: post #44
bmelton wrote: post #36

Earlier quoted context omitted.

That's a really good idea. Mazda is doing something that I think is fairly novel, which is almost exactly what you've described. They've scaled down the rotary engine from their RX cars to a single-rotor and put it into their new EV (almost tucked into the front wheel well,) and letting it act as a 70ish horsepower generator for the otherwise battery-powered car to extend range.

Mazda really seems like the only company innovating in the ICE space (this, wankel rotary engines, skyactive engines) and their cars look damn good these days too. On top of that, they make fun cars. With buttons and knobs on the dash! I'm glad they're still around doing their thing.

Mazda's also one of the few carmakers that's independent, as opposed to being part of a much larger conglomeration!

Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#47

Post by kube-system »

Syonyk wrote: post #37
causi wrote: post #14

Ok, so they're "shooting for" a performance of 1hp per 1.57 lbs of engine weight. A Toyota Camry engine produces 1hp for every 1.41 lbs of engine weight. It produces 1ft-lb of torque for every 1.94 pounds of engine weight, compared to 1.58 for the Camry. How is this revolutionary motor being outdone by a mid-range sedan engine?

> How is this revolutionary motor being outdone by a mid-range sedan engine? Go ask your Camry engine to make 100% rated power indefinitely, and see how long it holds up. That's the difference. A typical car engine is designed to make 30-50hp sustained, and occasionally generate more power for reasonably short periods of time. An aviation engine, generator engine, or any sort of "industrial" engine is going to be abl…

IIRC some automakers do test automotive engines at 100% duty cycle (in a test stand configuration). And more than a few automotive engines are used in slightly modified variants for marine and aviation applications.

As I understand, the reason a typical car engine can’t sit at 100% duty cycle isn’t the engine itself, but usually the cooling and oiling configuration.

Examples:

https://youtu.be/GNPB3RtHN2M

https://www.vikingaircraftengines.com/engine-options

Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#48

Post by rascul »

debacle wrote: post #3

My understanding is that everyone acknowledges that rotary engines are great, bt in comparison to piston based engines they have far shorter longevity.

Some years past, a friend who worked for Mazda explained to me that the engines need to be driven for a bit because until they're warmed up fully there can be a lot of carbon buildup and it needs to be run some amount of time to get the carbon through. Once they're warmed up and running for a bit they're fine. Supposedly it's the short trips of only a few miles that can kill them over time.

Not sure if that's correct.

Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#49

Post by qbrass »

Cockbrand wrote: post #23

Surely the engineers who came up with this are a lot smarter than myself, but to me it looks like the lower half of the rotor rotates into the combustion and thus has to work _against_ its force. If this is true, I'd assume that this takes away a lot of effectiveness.

It actually happens less on this engine than piston engines because the lobe on the rotor kind of rotates over the combustion chamber for a while instead of moving towards or away from it.

On the other hand, it exposes a lot of surface area to heat, which gets absorbed by the rotor but isn't used to turn the engine. It's a problem it shares with wankel engines. The advantage over wankels is the extra time air and fuel spends burning in the combustion chamber before the chamber volume expands. It means it gets more time to combust evenly which should help reduce both hydrocarbon and nitrogen oxide emissions.

Re: “Inside-out Wankel” rotary engine delivers 5X the power of a diesel

#50

Post by Syonyk »

causi wrote: post #38
Syonyk wrote: post #37

Earlier quoted context omitted.

> How is this revolutionary motor being outdone by a mid-range sedan engine? Go ask your Camry engine to make 100% rated power indefinitely, and see how long it holds up. That's the difference. A typical car engine is designed to make 30-50hp sustained, and occasionally generate more power for reasonably short periods of time. An aviation engine, generator engine, or any sort of "industrial" engine is going to be abl…

going to be able to sit there, making full rated horsepower, for thousands of hours without any trouble at all. The XTS-210 can do that?

If it's an aviation engine, it'd better be able to!
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