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

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

#201

Post by stametseater » Thu, Apr 06, 2023, 8:12 PM UTC

BWStearns wrote: post #192

stametseater wrote: post #119

Earlier quoted context omitted.

General aviation are perhaps the most cautious and wary ICE users around. Most of the engines used in GA, Lycomings and Continentals, are essentially 1960s designs with very well known cost, performance and reliability characteristics. That is not to say change is impossible, GA's overdue changeover to unleaded gasoline seems like an inevitability. Unleaded gas is already being approved for many of these engines, lik…

> General aviation are perhaps the most cautious and wary ICE users around. That depends on if you're describing the pilots or the ~manufacturers~ Textron. The experimental fleet has been pretty adventurous and it's a fast growing fleet. I think most of the conservatism in GA ICE tech has been driven by the broader issue of consolidation into a near monopoly on the cheaper end of the market. If you have no competitio…

It starts with GA pilots being very conservative with what kinds of planes they invest in, since planes are huge money sinks already. The old engines have very well characterized reliability and cost, so pilots know what they're getting into and can accurately plan for all their expenses. New planes/engines are proposed fairly regularly, but generally fail because there are too many unknown factors that buyers are wary of.

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

#202

Post by jldugger » Thu, Apr 06, 2023, 8:24 PM UTC

bagels wrote: post #27

Etheryte wrote: post #19

Earlier quoted context omitted.

We do this all the time with cylinders, no? I don't see how this is any different.

They were, I think, imagining placing the fuel injector on the moving part itself (eg the piston) which doesn't makes much sense to do, taking the inside out bit to the extreme.

Naw, im just dumb and imprecise. Need to rewatch and maybe reunderstand.

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

#203

Post by _hypx » Thu, Apr 06, 2023, 10:47 PM UTC

DesiLurker wrote: post #198

MichaelZuo wrote: post #195

Earlier quoted context omitted.

> Last I checked toyota's market cap was 220B+, they have been burning cash on Hydrogen fuel cell BS for a decade plus. that costs money too. BTW if a startup like Aquarious & some research center in UK can do it then so can they. all the rest of expenses come later when technology is promising & starts deploying. But thats when market also rewards you for innovation & not just maintaining you P/E ratios & EBITDA mar…

>The money Toyota 'burnt' on hydrogen stuff has already been spent Well was the decision to go all in on a entirely new tech (hydrogen fuel cells) was conscious choice by Toyota or not? So you agree that they have capacity to spend investment dollars, right? Now could they spend maybe an order of magnitude less money on improving ICE, Most definitely yes. Its definitely less costly trying to reinvent and entire new s…

Guys like you are totally deluded. BEVs are the real dead end and waste of resources. It is just replacing one unsustainable idea with another. And it can't even meet the driving needs of everyone anyways.

All car companies will inevitably have to pivot to hydrogen (or efuels or whatever). It is a matter of when and not if. If anything, Toyota is decades ahead of the competition.

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

#204

Post by _hypx » Thu, Apr 06, 2023, 11:07 PM UTC

midoridensha wrote: post #183

DesiLurker wrote: post #156

Earlier quoted context omitted.

yes I am well aware of Prius series configuration but it is still a regular engine shrunk down and fine tuned. What I am asking for is something very ground up redesigned for maximizing one thing only efficiency of energy conversion. couple of examples of this are Aquarius engines or [1]. basically you cut out all the unnecessary stuff and all the maintenance/repair plus cost with it. Current engines are complex beca…

I think you're greatly overestimating just how efficient a conventional ICE can be if designed and tuned for single-rpm, maximum-efficiency operation. Basically, the Chevy Volt is exactly the car you're describing. It wasn't that great: it had a separate engine that only ran a generator, and would only come on when the battery was depleted. The problem is having a full EV powertrain, plus an ICE driving a generator,…

Just FYI, the latest Prius Prime is functionally identical to the Chevy Volt. It just costs a lot less (starts at $33k). GM simply failed to design it properly.

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

#205

Post by seabird » Fri, Apr 07, 2023, 12:13 AM UTC

syrrim wrote: post #55

seabird wrote: post #42

Earlier quoted context omitted.

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.

If you had 18 such engines it would get you precisely 18x the performance, at precisely 18x the weight.

That's why there's all sorts of widely produced performance vehicles with multiple independent engines!

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

#206

Post by seabird » Fri, Apr 07, 2023, 12:18 AM UTC

93po wrote: post #81

seabird wrote: post #42

Earlier quoted context omitted.

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.

Ok, a Kawasaki H2R engine makes 326 horsepower and weighs about 160 pounds running regular fuel. That's almost identical to the Traxxas - 1hp for 0.49 pounds.

That engine is 4x heavier and supercharged. You're not comparing apples to apples.

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

#207

Post by Iwan-Zotow » Fri, Apr 07, 2023, 11:17 PM UTC

ghostpepper wrote: post #75

kube-system wrote: post #47

Earlier quoted context omitted.

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.…

The first time I learned you can increase, sometimes significantly, the performance of a car by upgrading the oil cooler blew my mind a little bit, but of course in hindsight it makes perfect sense.

WW2 planes engines

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

#208

Post by djaychela » Sat, Apr 08, 2023, 8:28 AM UTC

manarth wrote: post #34

djaychela wrote: post #5

Earlier quoted context omitted.

They also have issues meeting emissions targets - both because of the basic design (there isn't the ability to actively control valve timing events), and also because they typically need some sort of lubrication for the combustion chamber. They are similar to two-stroke engines in these respects.

Whilst also being worse-performing? Take a two-stroke Moster 185 engine: 25 HP at 7.800 RPM, for a 15kg package. I'd be keen to understand how (if) this outperforms a typical two-stroke.

I think it's difficult to make a direct comparison because of the way the capacity of the engines is calculated. I know it's "fair" from one point of view, but it's not from another (depending on which team you support).

The only straight-ish comparison I can think of is the Suzuki RE5 vs the GT500, which are same-era motorbikes from the same manufacturer, with roughly the same capacity. The RE5 wins on horsepower (62 vs 44), but weighs about 50kg more.

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

#209

Post by 93po » Tue, Apr 11, 2023, 4:48 PM UTC

seabird wrote: post #206

93po wrote: post #81

Earlier quoted context omitted.

Ok, a Kawasaki H2R engine makes 326 horsepower and weighs about 160 pounds running regular fuel. That's almost identical to the Traxxas - 1hp for 0.49 pounds.

That engine is 4x heavier and supercharged. You're not comparing apples to apples.

my point is that this ratio exists both much smaller and also somewhat larger. it makes sense this same ratio would be possible in the middle of the two as well. also diesels have super/turbo chargers all the time on production engines, why is that cheating?

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

#210

Post by sliken » Tue, Apr 18, 2023, 10:19 PM UTC

0cf8612b2e1e wrote: post #129

bluGill wrote: post #97

Earlier quoted context omitted.

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)?

Normal cars are designed from wide temperature ranges (something like -30F to 130F), -100 to 14k feet altitude, with a wide range of sand, dirt, snow, ice, hail and a wide variety of roads surfaces and steepness. Generally they seem designed to last 100k miles under normal use and terrible things don't happen if you forget an oil change.

You can do a chip tune that might get you more HP across a wide range of RPMs, but you won't be as robust, will need maintenance more often, and will likely wear through oil, gas, differentials, clutches, and related more quickly.

There's MANY things you can do that all basically come down to burning more gas+o2 in less time. Higher intake airflow (turbo, supercharger, better/missing air filters, scoops, etc), bored out cylinders for more engine displacement, more gas (increased fuel pressure/pumps), increased RPMs, and decreased exhaust pressure (better pipes, decreased or missing cats).

Trick is, more gas+o2 burned = more heat, more wear, more stress, hotter oil, faster clutch wearing, faster tire wearing, and generally faster brake wearing. Turbos are driven by exhaust, spin at crazy RPMs, increase air intake pressure, and generally are harder on the engine and oil and make cooling more of an issue. Higher RPMs require more precise timing, better valves+springs, better balanced cam shafts, etc. So what might seem like a cheap/easy change like increasing turbo boost from 10psi to 15psi might like a good idea, but have major impact on engine life and maintenance costs. A single blown head gasket from the increased temp, increased vibration, and increased pressure can be very expensive.

Much like CPUs of today, cars are generally designed carefully for their performance level and there's less spare performance left to be easily tweaked. Much like how older CPUs could be overclocked for substantial performance gains. Now both cars and CPUs will throttle if they don't have enough cooling or any of numerous other sensors detect potential problems. It's pretty common these days to see a car with 300hp, but 350hp for up to 10 seconds before the sensors reel you back in.