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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.
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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.
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My near-mint condition 2009 Mazda RX-8 never had a Wankel engine problem (over 100k miles). It would have easily lasted another 5 years without a doubt or hiccup. Wankels are usually excluded from all engine comparisons, because it's a considered a different class...for piston engine marketing reasons. I sold off my RX8 in 2018 because my fiancee and I moved to Seattle (passing emissions testing wasn't anything speci…
More antic-data: i worked with a guy whose brand new RX-8 needed two engines in the time we worked together. Granted, his was a 04 automatic, which is the worst combo. But still, Mazda didn't go out of their way to extend the engine warranties on the early RX-8s for no reason. Did you happen to have an 08+ model with the updated engine and/or remove teh catalytic converter?
In my case, I was taking a trip with my family and my RX-8 was blocking the driveway. We were running late for the flight, so I pulled it out, parked it back in the driveway, and let it idle there for 30 seconds knowing I'm not supposed to shut it down so quickly. But I had people waiting for me and what am I supposed to do, say "Sorry I own a strange car and I need to drive around the block for a bit to let it warm up!".
Of course that flooded the engine, but I didn't know until I got back from the trip. I followed all the instructions to de-flood the engine but it wasn't working for me so I had it towed to Mazda where they probably screwed it up further. It was there 2 weeks before they told me the engine needed to be replaced. They eventually had to fly an engineer from Japan to replace the engine since the dealer apparently had no one capable of dealing with rotaries. I think my car was at the dealer for a good 2 months. Thankfully all covered by warranty.
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…
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> 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.…
Marine applications generally means salt water, so they will run at higher power is the salt is what gets the engine eventually not the stress of high power output. Airplane engines are expected to be reliable and so they run at relatively lower power output. There are many small niches in between that have their own idea of what 100% duty cycle is.
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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.
That's a huge difference. The main limiting factor in engine power is mass air flow, not fuel. Engines are as much air pumps as they are containers for extracting expansion from explosions. Nitromethane provides extra oxidizer in liquid form, putting nitro engines in some ways closer to rocket engines in terms of power-to-weight ratio.
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?
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 commodity chainsaw (Stihl ms660) returns 1.4kg per kw from 2 stroke fuel. Before any performance tuning takes place. That’s at about a quarter of the size of this. I bet there’s efficiencies to be had if it were scaled up. I’m just not sure this is the game changing breakthrough the article’s tone suggests.
AFAIK there's nothing mechanically stopping you from scaling a 2-stroke, but it would very quickly render the immediate area noxious.
But they are simple, lightweight, and easy to shrink.
This is actually a really important point as we are trying to clamp down on VOC/NOx emissions. Ignoring CO2, two-strokes emit way more emissions than cars per unit work. But a 4-stroke engine, in addition to expense, does not lend itself to tools like chainsaws. In theory this engine could fill that niche.
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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.…
100% duty cycle doesn't really exists as stand alone concept. It is always in reference to the application. A typical car engine is at 100% duty cycle at around 30 horsepower, but the engine can produce 200+ horsepower for short bursts (enough to do the 0-60 test that everyone loves to quote). With more cooling you can run more power from the same engine, but the additional stress will mean the engine doesn't last as…
This exceeds most definitions of "100% duty cycle".