New engine shakes up auto industry
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Ralph Sarich invented the orbital engine [0] almost 40 years ago, formed a company and spent millions on the idea but it went nowhere. Interestingly, they knew when to change direction and ended up making a number of breakthroughs in the field of two stroke engines. The company is still in business today [1]
It obviously can still fail but I don't think it's possible to draw historical parallels.
That's not actually true. There have been an enormous variety of "impacts" from alternative engine designs. It's just that the engines that made the biggest "impacts" aren't "alternative" any more.
External-combustion engine: prior to 70 AD (aeolipile).
Internal-combustion rocket engine: 1200s.
Steam turbine (impact-turbine steam-jack): Taqi al-Din, 1600s.
Piston-vacuum steam engine: Newcomen, 1712.
Separate-condenser vacuum steam engine: Watt, 1765.
High-pressure steam engine: early 1800s, although maybe we should assign the credit to Hornblower, 1785.
Stirling engine: Stirling, 1816.
Otto engine: Otto, 1861 (or maybe some Italians in the 1850s.)
Two-stroke engine: Clerk, 1881.
Atkinson-cycle engine: Atkinson, 1882.
Rotary engine: Millet, 1889.
Diesel engine: Diesel, 1892.
Progressive-expansion turbine: Parsons, 1897.
Four-stroke diesel engine: Diesel, 1897.
Combustion-gas turbine: Elling, 1903.
Pulsejet (used in buzz-bombs): Karavodin, 1907.
Monosoupape, used in the Sopwith Camel: 1913.
Liquid-fueled rocket: Goddard, 1926.
Turbojet: Whittle and von Ohain, 1930s.
Ramjet: Leduc, 1936.
Turbofan: 1943.
Wankel engine: Wankel, 1954.
I've omitted minor changes like turbochargers, nozzle shapes, fuel injection, continuous-jerk camshafts, and so on; even though they're very practically important, I don't think they represent "alternative combustion engines". I've also omitted designs that haven't seen widespread use.
Now, from this, it looks like nothing has happened for 50 years. That is an illusion. The Atkinson engine only became significant in the last decade or two; Wankel's device only became significant in the 1970s; the ramjet didn't become significant until the 1950s; steam turbines went from a curiosity in the 1600s to the prime mover for much of the world's economy today, but it wasn't until Parsons' redesign that they really mattered.
Over the last 50 years, many new heat engine designs have been created: nutating-disc engines, thermoacoustic engines, the quasiturbine, scramjets, Stelzer's engine, the fluidyne engine, Sarich's orbital engine, the IRIS engine, and now this "wave disc generator". It's too early to tell which, if any, of these will turn out to be useful in the long run — at least as useful as the Wankel engine was in Mazda’s cars.
I guess I was specifically referring to car engines which, aside from the Wankel, are the same basic idea (pistons turning a crankshaft) that's been around forever. Yes, the technology has improved out of sight, and there's been a number of significant innovations like you've mentioned, but I've never seen anything outside the piston/crankshaft paradigm take hold.
About 15 years ago I was able to tour the Orbital Engine workshops and have a look at their stuff and chat to their engineers. At the time (mid 90's) they had developed a two stroke car engine they had running in a bmw. The engine made more power and torque, used about 20% less fuel and was about 30% lighter than the one it replaced, yet nothing ever came of it. [0]
I'd love to see this stuff happen, but I think the problem lies not with the technologies but rather that manufacturers are too conservative
[0] bloody hell, I've found one of the cars and it's on the market at the moment http://www.carsales.com.au/all-cars/private/details.aspx?seo...
Well, there have been a few commercially available cars driven by rotary engines (which are pistons being turned by a crankshaft, rather than turning a crankshaft) and cars driven by steam engines, but you're right that at the moment, only Otto-cylinder, Diesel, Atkinson, and Otto Wankel engines are on the market for cars, and all of these except for the Wankel are built around pistons turning a crankshaft.
But if you're talking about innovations on the level of more-efficient two-stroke engines, rather than totally new engine designs, I think you can find a lot of those that have made it to mass production in the last few decades. Atkinson-electric hybrids might be the biggest one, but there's electronic ignition control, gasoline direct injection, electronic fuel injection, coaxial springs to prevent valve dwell, continuous-jerk cams, hydraulic tappets, variable valve timing, etc.
That list certainly supports your contention that manufacturers are too conservative, though.
(I don't really know much about this stuff, so let me know if I'm making some kind of goofy mistake.)
It seems to me that in order to make manufacturers less conservative, we need to have more of them. Widespread CAD and simulation facilities and automated fabrication that lowers the cost of producing prototypes could make a big difference.
BTW, the SyTech is another experimental non-crankshaft design: http://www.autospeed.com/cms/A_0948/article.html
It should be noted than 25kW is 33HP. Though it's possible to make a useful car with that little power, 33HP is generally considered an appropriate power level for a beginner's motorcycle, not a car. Even if it's much lighter than a piston engine and has such a wide powerband that it doesn't need a gearbox, it's likely they'd need a lot more power for consumer acceptance even in small cars.
Edit: I googled this and found that the intent is to use this engine to run generators to charge batteries in hybrid cars, not for direct propulsion. In that case, the cars probably won't be much, if any lighter than standard cars since all the weight savings will be replaced with batteries. Power output could, of course be lower than a standard car engine and still provide good performance since the electric motors could have peak outputs far exceeding the sustained output of the generator.
P.S. For clarity's sake, modern hybrids are enormous compromises due to the weight of the battery and electric motor. For a hybrid you want the highest efficiency possible and thus the lowest total vehicle weight you can manage without compromise safety. The necessity of heavy batteries fights in the opposite direction, so in order to produce a fuel efficient vehicle car makers use more expensive, lighter weight materials in the construction of the vehicle. This increases the complexity of manufacturing (more different materials are being used) and raises the price of the vehicle. If you could drop in a drive-train which kept the weight the same that would change the industry dramatically.
Internal combustion engines and electric motors are also not rated in the same way. Electric motor HP is "rated" horsepower (what it can produce continuously without overheating; generally it's capable of more for short periods) while internal combustion horsepower tends to be "maximum" horsepower and there are a lot of different ways to come up with a number, some purely based on calculations and some on actual measurement. So unfortunately HP is not an apples-to-apples number between electric and combustion engines.
Not to mention cheaper cars!!!!!
It is not likely that a hybrid car with no direct propulsion from the combustion engine will be 1000 pounds lighter than a comparable conventional car, even if its combustion engine weighs next to nothing. Batteries are heavy, and this type of hybrid needs more of them than the more common type that uses electric to augment the power of a combustion engine.
I'm not saying this won't be an improvement. I'm just saying some of the claims seem a little extravagant.
40hp is about what you use on the freeway, or at least it used to be before the average car came to weight 2 tons. You don't need a whole lot more than that. Hell, the MG Midget was offered with a 30HP engine once, IIRC.
I'm quite sure in a decade or two we're going to have people saying things like, "It's true you CAN make a car with only 200hp, but it's generally accepted you need at least 800hp for any car"...
I think the average US car weighed a lot more in the 1960s than in the 1970s, 1980s, or 1990s. Maybe widespread SUV use is pushing that average back up.
Did the http://en.wikipedia.org/wiki/Deux_Chevaux really have only two horsepower?
The fact that a car was once successfully sold in Europe with such a low power to weight ratio doesn't mean it would succeed in today's market. Consumer expectations have changed. They could change again, but there would have to be a good reason.
[0] Lighter cars could be made from more exotic materials, but those would drive the price out of reach of the average buyer.
I can't wait, thanks for the cheery prediction!
I couldn't tell you if the thing is real or not.
But, if such an engine, with two-three times(!!!) the efficiency of a standard gasoline engine with a lower power to weight ratio, were to be producible at 25kW, all the (hypothetical underpowering) problems could be solved by ...
... using ...
TWO engines!! (or three engines)
... jeesh ...
It's for hybrids. Each engine would just charge a battery.
Oh - yeah: I drove a hell of a lot on the German Autobahn with it as well. Fast? Hell no. But I still have that speeding ticket (went just a tiny bit faster than 100km/h) somewhere as a nice souvenir.
0: https://secure.wikimedia.org/wikipedia/en/wiki/Citro%C3%ABn_...
Not only it's possible, but many successful european cars hadn't more : Citröen 2CV, Renault 4CV, Fiat 500 and 600, and most other economy cars of the 50s and 60s hadn't even that power, and sold by the millions.
But the design obviously isn't limited to this? A bigger engine could give more power yet still consume less than a regular piston engine. Or 1-2 of these running in parallel, depending on the load.
Also, it's important to note the reason for the big discrepancy between the "inflated" horsepower ratings modern cars have vs. the lower HP in older classic cars: power is RPM * torque, and gas engines are rated in peak horsepower. To reach the advertised peak horsepower of modern engines, you have to be fairly high RPM (5K to 6K) whereas an older, lower horsepower rated engine might start to drop off its power curve after 4K. But at lower RPM the torques may be similar, or even higher for some older engines (the VW engine in particular with its Boxer configuration was optimized to have good torque for its size). What this means is that unless you are driving full throttle all the time at high RPM, you're not necessarily pushing all 100+ horsepower or whatever that your modern engine is capable of in theory, and so conversely an engine with smaller max horsepower is not as much worse as you'd think it would be.
I'll pay attention once this happens. As they say, there's many a slip between the cup and the lip. Lab projections invariably end up being over-optimistic.
Even if the claims they're making do turn out to be true, it could still suck in any number of other ways. How durable is this engine? Is it still gonna be running after a hundred thousand miles?
I am just as skeptical, but if this is how they get their funding to build that working prototype than I'd say it's fair enough.
Eventually people tire of playing the rotary game, usually when they realize the weight savings and high redline aren't worth the numerous flaws on anything but a track car (and even then, only if you can live without much low-end torque).
The RX-7's rotary engine (the 13B series) is actually phenomenally reliable, and there are many examples with well over 300k road miles. The RX-8 uses a newer variant of the same engine - the 13B-MSP RENESIS. Additionally, Mazda used the rotary in competition (in the infamous Mazda 787B) at the 24 hours of LeMans, which is a notoriously difficult test of engine reliability.
The myth of poor rotary reliability primarily stems from the 3rd-generation RX-7. The notoriously-complex mechanically-controlled sequential twin-turbo system (affectionately known as "the rat nest") was prone to hose disconnects and failures, which often led to over-boost situations. Additionally, owners that modify their cars often exacerbated the problem, installing free-flowing intakes and exhausts, as well as boost controllers, and did not properly modify air-fuel ratios to compensate. These situations led to increased engine heat and premature failure, which gave the rotary an unfair bad reputation. Many owners now convert to a simpler single-turbo setup with electronic boost control and careful air-fuel tuning, which is far more reliable.
The actual (and admittedly significant) drawbacks of rotary engines are poor fuel efficiency and high exhaust emissions, both due to incomplete combustion. This has kept them out of mainstream applications and thus they tend to be used primarily in performance applications.
This is also untrue; the rotary is much simpler than a piston engine and has far fewer moving parts. Replacing major mechanical components on a rotary is easier than a reciprocating engine. As long as the associated systems are also simple, the rotary is one of the easiest engines there is to repair.
Most work that has to be done on car engines has nothing to do with the engine itself, but control, ignition and fuel delivery systems. Older rotaries had carburetors, which required regular adjustments to keep in tune. As mentioned above, the third-generation RX-7 had a complicated twin-turbo system that created some reliability problems of its own. Non-turbocharged fuel-injected second-generation RX-7s on the other hand are some of the most reliable and low-maintenance sports cars ever produced.
He could be talking about cold fusion in just the same way ;)
[edit] looking at the duplicate link, they refer to their own article from 2006. Cold fusion would either have been laughed away or taken over the world. Same thing here I would assume. [/edit]
There is even productized version of rotary-vane engine coming supposedly next year in a Russian car:
http://www.fastcompany.com/1709400/russian-billionaire-unlea...
I'd be though very surprised if they pull it off as beside Mazda rotary i don't know other mass-produced cars with non-traditional engines.