5 ms·
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-
by mywittyname 4y ago
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 actually release a commercially viable product. 20 years to design an ICE is...too much.
- Zak 4y agoThe specific version described in the article appears to be a Diesel rotary that runs on jet fuel with military UAVs as a primary application.
- Cthulhu_ 4y agoI 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 case for that was to have the pistons move through coils, thus generating electricity. We used to have a flashlight that works with the same principle, shake it to generate electricity.
- themaninthedark 4y agoMy 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.
- adgjlsfhk1 4y agothis is backwards. the reason cargo ship engines are big is because they don't care about size. they would rather have a 2x bigger engine that was 1% more efficient
- leansensei 4y ago> this is backwards. the reason cargo ship engines are big is because they don't care about size. they would rather have a 2x bigger engine that was 1% more efficient Depends on the fuel cost.
- lazide 4y agoHow so? 2x bigger has no bearing on fuel cost, but efficiency does.
- LargoLasskhyfv 4y agoOr the fuel volume. Think of LNG-powered LNG-tankers. Like these: https://en.wikipedia.org/wiki/CMA_CGM_Jacques_Saad%C3%A9 https://en.wikipedia.org/wiki/CMA_CGM_Jacques_Saad%C3%A9
- anecdotal1 4y agoDoes it? They only need to get to it international waters and then they switch to bunker fuel which is as cheap as it gets
- lb1lf 4y agoThere's an awful lot of room on a cargo ship. They don't care too much about size. They only care about total cost of ownership. Edit: ninja'd!
- astral303 4y agorotary engines do not really scream at peak power... this is why Mazda has plans to use rotary at peak power to generate electricity for their hybrid EVs. re 20 years to make a new engine point, compare investment $ in traditional ICE across the car industry vs investment $ into rotary or other alternative engines (the former is order of magnitudes more)
- red-iron-pine 4y agoMazda still holding on to those rotary engines, eh? Still, call my interest piqued. I'll keep an eye out for their Wankel-EVs
- shortsightedsid 4y agohttps://www.youtube.com/watch?v=-3gzQVGEqF4 https://www.youtube.com/watch?v=-3gzQVGEqF4 explains the details. As usual Jason's awesome at explaining the details.
- lazide 4y agoThe issue with Wankels has always been seals.
- rgmerk 4y agoAs cool as the rotary engine is, Mazda’s attempt at a rotary hybrid is flogging the deadest of dead horses.
- heelix 4y agoWe will be driving an old RX7 in the '24 hours of Lemons' this year. Looking forward to pushing it in a nice casual race. Mechanically, we were not at a point where it was solid enough for 2022. I think the rotary engine was the only thing that was working. :)
- jacquesm 4y agoGood luck with the seals! Between rotary and Stirling I find it hard to pick a favorite and both of them have similar problems despite the completely different geometry.
- hommelix 4y agoYes this ils comparing apple and banana. 2-stroke vs 4-stroke, supercharged vs naturally aspired.
- stronglikedan 4y agoIf it's truly a 5x size reduction, then there's still plenty of room for sound dampening materials!
- toss1 4y agoSeems 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/ https://www.aieuk.com/225cs-40bhp-wankel-rotary-engine/
- m463 4y agobtw: I had a mazda rotary engine car, and the 7000rpm shown on the tach seemed exciting compared to a piston engine... except it wasn't really true. It really ran at 1/3 that speed.
- pengaru 4y agoThere's only a grain of truth to what you're saying here. The eccentric shaft does indeed spin at the indicated RPM, just as a crankshaft on a piston motor does. It's just the rotors move at 1/3rd the eccentric shaft's rate, which is a design feature enabling substantially higher than 7000RPM with little effort.