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

newatlas.com

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

#121

Post by themaninthedark »

Cthulhu_ wrote: post #106
Zak wrote: post #33

Earlier quoted context omitted.

The specific version described in the article appears to be a Diesel rotary that runs on jet fuel with military UAVs as a primary application.

I think a lot of commenters in articles like this will only think about automotive as a use case for alternative engine designs. I'm reminded of a linear piston engine (iirc two pistons that just go back and forth without their motion being translated into rotation; one where they were side-by-side moving alternately, the other one where they'd actually move towards each other and share a combustion chamber). The use…

My first thought went to cargo ships. They require huge motors, so I imagine that if you can keep or gain performance while reducing size they would be very interested.

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

#122

Post by codeflo »

bluGill wrote: post #101
codeflo wrote: post #83

Earlier quoted context omitted.

I know this is off-topic, but I'm curious. I always had the impression that even in the US, standard units are used for engineering. Reading about "ft-lb" makes me think I was wrong (and my head hurt, tbh). Do you really compute stuff like torque in imperial units? Don't you need weird factors in every formula to make that work?

There are lots of weird factors in engineering anyway. We have different factors, but there are still factors. Besides, nobody is calculating this, they are measuring and that is just a matter of what label you put on the dial. Most engineering in the US is done in metric units. Then marketing applies a metric to imperial conversion. I suspect China does more engineering in imperial than the US, both in total an per…

> Besides, nobody is calculating this, they are measuring and that is just a matter of what label you put on the dial.

That's why I asked about engineering, not driving. Nobody converts torque to power etc.?

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

#123

Post by mannykannot »

abfan1127 wrote: post #86
m3047 wrote: post #84

Earlier quoted context omitted.

2 stroke has poor unburned emissions because of mix flow-through when ports are open. If air charge / purge is completed before fuel is injected then that doesn't occur; whether that's diesel or something else is irrelevant. As a bonus, built in EGR if properly managed.

I thought 2-strokes had poor emissions was the injection of lubrication oil into the air fuel mixture. traditional 2-strokes I'm familiar with pull in air into the crank case (which requires lubrication), then uses a portion of the exhaust stroke to compress the fuel/air creating forced induction. By keeping air out of the crank case and providing lubrication delivery outside of the air/fuel mixture, emissions can be…

The basic crankcase-scavenged two-stroke suffers from both problems. Typical diesel two-strokes use a separate blower for scavenging, so the combustion air inflow never passes through the crankcase and does not come in contact with the lubricating oil, while the fuel is not injected until after the exhaust is closed.

The engine described here can have its shaft and eccentric bearings externally lubricated, but its apex seals, like those of Wankel engines, seem to be in a situation analogous to that of a piston ring. Unlike either of those, however, they are mounted in the stator, not the moving part, and so may be easier to lubricate precisely.

https://www.cycleworld.com/2015/04/06/two-stroke-motorcycle-...

https://auto.howstuffworks.com/diesel-two-stroke1.htm

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

#124

Post by tacroqueen »

elihu wrote: post #78

Kind of weird article that doesn't talk about either the main benefits or design hurdles. The advantage of the LiquidPiston design is that at the time of ignition, the combustion chamber is a roughly round shape, as opposed to a traditional rotary where it's a long crescent. This should theoretically improve the emissions and fuel economy to be more like piston engines. I don't think Liquid Piston was talking about a…

I don't think New Atlas is a reputable site.

https://medium.com/democratizing-finance/liquid-piston-insid...

This is likely all part of a pump and dump. That's why it's a weird article.

They've been advertising this heavily of all places on instagram and taboola chumboxes. Obviously none of those people need this engine, they're looking for marks.

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

#125

Post by toss1 »

mywittyname wrote: post #10

A non-turbo diesel is an interesting choice of competitor. The big selling point of the Kohler motor is that it's almost silent - even the valve train is belt-driven to reduce noise. Not sure a rotary engine screaming at 6500RPM is comparable here to a diesel with a peak torque at 2000 and peak power at 3600. > LiquidPiston has been working on these X-engines for nearly 20 years now, I'm guessing they will never actu…

Seems likely. Several years ago when working on a hybrid-powered UAV, I was checking out high power/weight engine platforms, and actual Wankels in development or available did better.

A 30sec DDG search turned up options that are definitely better, e.g., the AIE 80S, with 15BHP/11.2kW at 5kg or their 225CS, with 40BHP/30kW at 10kg [0]. In contrast, this weighs 19kg to produce 26HP/20kW. The net power - weight for these Wankels is 2.24kW/kg and 3.0 kW/kg vs Liquid Piston's 1.05kW/kg.

While IDK about availability from AIE (it just turned up at the top of the search), I know there are others on the market that are/were available. Meanwhile the LP prototype still isn't available 7+ years after I was first looking at them, and the were suppose to ship "real soon now".

We'll see...

[0] https://www.aieuk.com/225cs-40bhp-wankel-rotary-engine/

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

#127

Post by bluGill »

codeflo wrote: post #122
bluGill wrote: post #101

Earlier quoted context omitted.

There are lots of weird factors in engineering anyway. We have different factors, but there are still factors. Besides, nobody is calculating this, they are measuring and that is just a matter of what label you put on the dial. Most engineering in the US is done in metric units. Then marketing applies a metric to imperial conversion. I suspect China does more engineering in imperial than the US, both in total an per…

> Besides, nobody is calculating this, they are measuring and that is just a matter of what label you put on the dial. That's why I asked about engineering, not driving. Nobody converts torque to power etc.?

The engineers who do that are using metric. Marketing might do this conversion, but they just plug it into a converter and have no reason to know anything more than bigger is better.

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

#128

Post by skullone »

vvillena wrote: post #31
skullone wrote: post #7

Earlier quoted context omitted.

Running them at a pre-determined RPM constantly can resolve lack of VVT, but that limits their applications. New materials for apex seals being researched could alleviate their longevity issues too. But, I have a big soft spot for rotaries and would love to see them applied more :(

Isn't this how the range extender in the MX-30 works?

Ohhhhh interesting, this would be a perfect fit for a range extender!

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

#129

Post by 0cf8612b2e1e »

bluGill wrote: post #97
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.

Every motorcycle mechanic I've seen has a sign in the shop: speed costs money, how fast do you want to go. That sign isn't referring to the costs to modify an engine to go faster so much as the cost to constantly rebuild the engine after they modify it to go fast. I've seen two identical engines, one rebuilt to stock and one rebuilt to max speed - the cost for both rebuild jobs was about the same (the parts for speed…

What is done to modify an engine for speed? What kind of improvement can be seen for speed (accelerates XX faster? YY higher top speed)?

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

#130

Post by HWR_14 »

jldugger wrote: post #15

I guess the "inside out" is that the rotary block is also the fuel injector? Would have to read more to figure out how they get fuel into a thing moving at thousands of rpm.

A traditional Wankel engine has a rotary block in the shape of a reuleaux triangle moving in a more cylindrical stationary chamber. The "inside out" refers to how this engine is a more cylindrical rotary block moving inside a stationary reuleaux triangle chamber.
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