5 ms·

Surprising that there's still that much efficiency to be squeezed out of internal combustion engines!

Animats 3y ago
Yes. Makes you wonder how real this is. And how long it lasts. The military might want it for drones. Even if it's only good for an hour, that's a good survival time in modern combat.
- smcleod 3y ago
  I think it probably is real, Mazda has a new single rotor engine they've got in the new MX30 hybrid, it's used to extend the range https://www.drive.com.au/news/2023-mazda-mx-30-r-ev-revealed/ https://www.drive.com.au/news/2023-mazda-mx-30-r-ev-revealed...
- wongarsu 3y ago
  They mention "the XTS-210 engine addresses the fuel efficiency, lubrication, and fuel type limitations of the traditional Wankel rotary engine", but while they quote great fuel compatibility, don't waste more words on efficiency and lubrication. So just based on the marketing fluff I expect those two points to still be worse than traditional diesel engines, just good enough for military applications. And given the other advantages the military might be completely ok with a fuel-guzzling hard-to-maintain engine for certain applications, wouldn't be the first time
  - Phlarp 3y ago
    Adding in the 2 stroke design and wide ranging fuel compatibility to the above military centric specs, I have to imagine the emissions profile is truly stunning.
  - inferiorhuman 3y ago
    Dollars to donuts the rotary will be easier to manufacture and maintain than the diesel. It's got fewer parts and the parts themselves are way simpler. Lubrication's easy if you don't care about efficiency or emissions, which the military doesn't.
    - nine_k 3y ago
      The military does care about efficiency: higher efficiency means longer range, as we seem to be talking about aircraft / rotocraft applications. Higher wear is what they care less about: at peacetime, parts can be replaced more often, and at wartime, many will be destroyed before spending up the spec-dictated operation hours.
      - inferiorhuman 3y ago
        Right - they care about range, fuel efficiency is secondary at best. WRT this engine, it's too small for anything but a small-mid sized drone. In that context the specific fuel consumption is likely less of an issue as there's some pretty hefty weight and size savings over the comparable piston engine (and they're claiming better fuel efficiency). The issue with the parts isn't higher wear, it's simplicity. Look at the strain that Ukraine has put on military supply chains. Now take a look at what's involved in building a diesel engine versus a rotary. The rotary engine is a few relatively simple castings*, a piston engine has a ton of small, complex parts. There's no mention if they comparable diesels are two or four stroke, but take a look at a four stroke injection pump and how complex they are (inline pumps are basically mini piston engines). Then take a look at the LiquidPiston motor – at least on one variant they're using the crankshaft for fuel and air delivery. Pretty much everything about it is simpler than a comparable piston engine, and when you've gotta scale up wartime production simpler is better. * okay so it looks like LiquidPiston is milling everything for the time being.
        nine_k 3y ago
        This is right; the simpler, the cheaper and faster to make, and often the harder to break. Very important in the military. Delivering fuel and lubrication via the crankshaft is not uncommon in aircraft motors, or was at times of WWII at least. Delivering air this way is indeed novel and impressive.
        inferiorhuman 3y ago
        https://www.liquidpiston.com/how-its-made https://www.liquidpiston.com/how-its-made If I'm not mistaken there are no apex seals in there – so there's one major weakness eliminated. Regardless of military applications there is some real interesting engineering there.
deleted 3y ago
[deleted]
bluGill 3y ago
They are squeezing small size out, not efficiency. You can get more power from a small engine, but you trade long term reliability when you do.

Yes. Makes you wonder how real this is. And how long it lasts. The military might want it for drones. Even if it's only good for an hour, that's a good survival time in modern combat.

smcleod 3y ago
I think it probably is real, Mazda has a new single rotor engine they've got in the new MX30 hybrid, it's used to extend the range https://www.drive.com.au/news/2023-mazda-mx-30-r-ev-revealed/ https://www.drive.com.au/news/2023-mazda-mx-30-r-ev-revealed...
wongarsu 3y ago
They mention "the XTS-210 engine addresses the fuel efficiency, lubrication, and fuel type limitations of the traditional Wankel rotary engine", but while they quote great fuel compatibility, don't waste more words on efficiency and lubrication. So just based on the marketing fluff I expect those two points to still be worse than traditional diesel engines, just good enough for military applications. And given the other advantages the military might be completely ok with a fuel-guzzling hard-to-maintain engine for certain applications, wouldn't be the first time
- Phlarp 3y ago
  Adding in the 2 stroke design and wide ranging fuel compatibility to the above military centric specs, I have to imagine the emissions profile is truly stunning.
- inferiorhuman 3y ago
  Dollars to donuts the rotary will be easier to manufacture and maintain than the diesel. It's got fewer parts and the parts themselves are way simpler. Lubrication's easy if you don't care about efficiency or emissions, which the military doesn't.
  - nine_k 3y ago
    The military does care about efficiency: higher efficiency means longer range, as we seem to be talking about aircraft / rotocraft applications. Higher wear is what they care less about: at peacetime, parts can be replaced more often, and at wartime, many will be destroyed before spending up the spec-dictated operation hours.
    - inferiorhuman 3y ago
      Right - they care about range, fuel efficiency is secondary at best. WRT this engine, it's too small for anything but a small-mid sized drone. In that context the specific fuel consumption is likely less of an issue as there's some pretty hefty weight and size savings over the comparable piston engine (and they're claiming better fuel efficiency). The issue with the parts isn't higher wear, it's simplicity. Look at the strain that Ukraine has put on military supply chains. Now take a look at what's involved in building a diesel engine versus a rotary. The rotary engine is a few relatively simple castings*, a piston engine has a ton of small, complex parts. There's no mention if they comparable diesels are two or four stroke, but take a look at a four stroke injection pump and how complex they are (inline pumps are basically mini piston engines). Then take a look at the LiquidPiston motor – at least on one variant they're using the crankshaft for fuel and air delivery. Pretty much everything about it is simpler than a comparable piston engine, and when you've gotta scale up wartime production simpler is better. * okay so it looks like LiquidPiston is milling everything for the time being.
      - nine_k 3y ago
        This is right; the simpler, the cheaper and faster to make, and often the harder to break. Very important in the military. Delivering fuel and lubrication via the crankshaft is not uncommon in aircraft motors, or was at times of WWII at least. Delivering air this way is indeed novel and impressive.
        inferiorhuman 3y ago
        https://www.liquidpiston.com/how-its-made https://www.liquidpiston.com/how-its-made If I'm not mistaken there are no apex seals in there – so there's one major weakness eliminated. Regardless of military applications there is some real interesting engineering there.

deleted 3y ago

[deleted]

bluGill 3y ago

They are squeezing small size out, not efficiency. You can get more power from a small engine, but you trade long term reliability when you do.