germanbird writes: "Jalopnik has an interesting article up about Koenigsegg's Prototype Camless Engine. The engine uses pneumatic actuators rather than a cam to open and close the valves in the engine. The engineers behind this claim that it can provide "30 percent more power and torque, and up to 50 percent better economy" when applied to an existing engine designs. The article and some of the comments also mention that some work has been done with electromagnetic actuators to accomplish the same task. It may be a while before this tech is mature enough for passenger vehicles, but maybe if a racing series or two picked it up, it might give some of the manufacturers the opportunity to work the bugs out?
Not sure this is on topic for SoylentNews, but the article brought me back to my introduction to engineering course in college. One of my classmates was a car nut and I remember a discussion with an EE professor one day about the potential (or actually lack thereof due to performance issues) for using electric actuators to open and close valves."
(Score: 5, Interesting) by Phoenix666 on Friday February 28 2014, @10:22AM
This rather strikes me the same way a similar article would on how to get 30% more efficiency out of a steam engine. Great improvement, but being entirely eclipsed by another form of locomotion: electric. It's cheaper, faster, quieter, more powerful, and greener by far than any ICE. My brother is an automotive engineer at Ford. He recently went to Chicago to test drive a Model S, came home, and immediately put together his resume to apply to work at Tesla. Yes, anecdote != data, but voting with your feet seems the sincerest expression of intent. Wait until the next generation of batteries hits the market--you'll see millions of others doing the same. Me, I'm trying to time things so I can dump my ICE while I still can and jump to an electric I can afford.
Washington DC delenda est.
(Score: 5, Insightful) by Anonymous Coward on Friday February 28 2014, @11:57AM
You are aware that modern power plants (with the exception of hydro, wind and solar) all run on modern, highly efficient versions of a steam engine?
Even if one day no car in the world uses an ICE motor any more, that doesn't mean ICE motors would completely become irrelevant. For example, I can imagine that they continue to be used for emergency backup generators.
But frankly, I'd not be surprised if the future turned out to be not electric cars, but petrol produced from carbon dioxide and water using electric energy from renewable sources. After all, the problem is not burning carbon, the problem is burning fossil carbon.
(Score: 3, Interesting) by Grishnakh on Friday February 28 2014, @04:16PM
Petrol/gasoline, no matter where you get it, is still horrifically inefficient. Most of the energy goes into producing waste heat. I don't care if you come up with a way of producing it entirely from renewable sources, you'll still waste most of that energy as heat in an ICE engine. What's why they need to be phased out. You'll never get over about 40% efficiency on an ICE.
Electric motors, on the other hand, are between 90 and 98% efficient.
The only problem with electric cars is the battery tech. If we had inexpensive, safe, reliable batteries the size of a car's gas tank capable of storing 1/3 to 1/2 of the energy stored in that same volume of gasoline, we'd be golden. (You only need a fraction since, as I said before, most of that gasoline's energy goes simply to producing waste heat.) We're getting closer, as exemplified with Tesla cars (range: 200+ miles), but we're not there, most particularly on the "inexpensive" property. If we could make Tesla car batteries for $1000, we wouldn't have ICE cars any more.
How fast we're going to get to that point is up for debate.
(Score: 3, Insightful) by mhajicek on Friday February 28 2014, @05:19PM
True, but until we do get there ICE's have their place. Also, in cold climates that "waste" heat can be rather useful.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 3, Interesting) by Grishnakh on Friday February 28 2014, @05:50PM
Even in cold climates, the waste heat thing isn't that useful; the problem is that it takes a little while for the car engine to warm up enough for your heater to start working. In a Tesla, the car starts blowing hot air from the heater into the cabin and onto the windshield as soon as you start it up. Obviously, this takes a toll on your range, but still, it's a lot more convenient. With a gas car, either you freeze your ass off for 5-10 minutes (depending on how fast you can get on the highway vs. sitting in traffic; car engines don't warm up quickly when idling), or you can remote-start your (automatic only) car and let it idle for 20-30 minutes and warm up, wasting a bunch of gas and also wearing down your engine (engine oil gets contaminated faster at idle, or so I've read).
One thing that helps is to get a car with heated seats and steering wheel. That makes the cold air much more bearable for those first 10 minutes, since heated seats don't take much time to get warm.
(Score: 2) by frojack on Friday February 28 2014, @07:15PM
Well Electric motors produce waste heat too. You do work, you will invariably waste some heat.
And, given current storage capacity of battery technology, that probably has a much greater effect.
A rich man can lose a 100 dollar bill and not worry, but a poor man can't afford that.
The energy density of Gas/Diesel allows some waste heat, and quite frankly I don't think the industry has even focused on that aspect of efficiency.
If this guy can in fact get 30 percent (which I doubt) it puts us that much closer to wringing as much energy out of gas as is possible.
No, you are mistaken. I've always had this sig.
(Score: 3, Interesting) by Grishnakh on Friday February 28 2014, @08:43PM
Well Electric motors produce waste heat too.
You've got to be kidding. You do realize that ~95% efficiency is far better than ~30% efficiency, right? No one ever said electric motors were perfect.
And, given current storage capacity of battery technology, that probably has a much greater effect.
Tesla has cars with almost 300-mile range now, largely thanks to that massive efficiency difference. The storage capacity of batteries is not a big problem any more. Their cost/Ah and recharge rates are.
The energy density of Gas/Diesel allows some waste heat, and quite frankly I don't think the industry has even focused on that aspect of efficiency.
Huh? They've been pushing for tiny fuel efficiency improvements for ages. You can only do so much with a Carnot Cycle engine, especially at small scales. Go read about Carnot Cycle on Wikipedia; the other name for an ICE is a "heat engine". The way it works is exploiting the difference in temperature between hot and cold reservoirs, the hot being the combustion and the cold being the environment, and it's limited by the Carnot Theorem; you can only get 100% efficiency with infinite temperature; real-world is 40-60% (closer to 40% for car engines).
If this guy can in fact get 30 percent (which I doubt) it puts us that much closer to wringing as much energy out of gas as is possible.
Simple math: a 30% improvement (which I agree is very highly dubious) on 30% efficiency gets you to 39%, which is still far, far away from ~95%.
(Score: 3, Insightful) by frojack on Friday February 28 2014, @09:15PM
Even simpler truth: Because you move inefficiency from one place in a system to another, doesn't give you the right to disavow all inefficiency.
For instance Look here: http://www.eia.gov/tools/faqs/faq.cfm?id=107&t=3 [eia.gov]
Follow the 2nd link to the tables, and compute the efficiency of the various methods of electrical generation.
So 40% doesn't look so bad now does it!
No, you are mistaken. I've always had this sig.
(Score: 2) by The Mighty Buzzard on Friday February 28 2014, @08:48PM
My rights don't end where your fear begins.
(Score: 2) by Grishnakh on Friday February 28 2014, @09:36PM
So what? The efficiency of large power plants is far better than small ICE engines, even after accounting for transmission line losses. There's less pollution too, since power plants are regularly maintained, unlike typical car engines that may or may not be maintained properly, and are frequently kept running long after they should have been junked.
(Score: 5, Informative) by gallondr00nk on Friday February 28 2014, @12:09PM
There's still plenty of applications even if the next generation of electric cars can displace traditional ones. I'd wager you won't see feasable electric trucks for a while, for example. Marine engines and diesel generators would benefit as well.
Up to 50% economy gain at this stage is pretty incredible, considering how mature the technology is.
The idea of being able to adjust the number of firing cylinders has been done before [wikipedia.org]. But actually being able to swap between 2 and 4 stroke at will? Pretty incredible. I suppose the question now is can it cope with 100,000+ miles?
(Score: 3, Interesting) by geb on Friday February 28 2014, @12:14PM
Internal combustion will have its place for a long time to come. The big draw of hydrocarbon as a fuel is the energy density, and there are some applications where you really need that.
There have been battery-electric aircraft for instance, and they were a bit crap. (There has even been an aircraft that ran on AA cells, and that was extremely crap.)
At the other end of the scale, you've got huge cargo ships, where long distance endurance and efficiency are both absolute requirements. Engine designs there are highly varied, but there are still a lot of piston engines being built. The article mentions that this tech originated in ship engines, and is being adapted to cars just because there's no reason not to.
(Score: 2, Insightful) by emg on Friday February 28 2014, @04:55PM
"Great improvement, but being entirely eclipsed by another form of locomotion: electric"
Uh, yeah. That'll be why I see so many electric cars on the road every day.
You appear to be unaware that electric cars are an older technology than ICE cars, and vanished very quickly once the ICE became viable. Our ancestors dumped them because they sucked ass, and they still suck ass for all the same reasons.
Until there's an electric car that can travel 500+ miles on a charge, recharge in five minutes, and work almost as well at night at -40 as it does during the day in California, they're not going to 'eclipse' ICE cars.
(Score: 3, Insightful) by hemocyanin on Friday February 28 2014, @05:09PM
The issue with electric cars isn't the motor -- there is no question that is superior. The issue is the battery. Until we really solve battery issues, and by that I don't just mean energy density but the ability to make energy dense batteries from ridiculously common materials that don't require removing entire mountains to get at, electric cars are going to be for the wealthier people of the world -- those who can afford to have an extra car for local trips, while keeping a regular car for any trip beyond 45 miles(*) each way (I'm thinking of the Nissan Leaf -- $28k for base model, DIY cost of charger +$1000 (pro install +$2000 (includes charger)), 86 mile range. This is a car for people rich enough to have a spare car. People who buy Teslas are definitely rich).
(*) that would use the entire capacity of the battery which probably isn't good for its longevity.
(Score: 2) by buswolley on Friday February 28 2014, @05:43PM
The primary advantage of electric vehicles is that pollution is restricted to a single location, namely the power plant. If the power is driven by coal then there is no substantive advantage. If the power plant is driven by solar, wind, fusion, then there are substantive advantages.
subicular junctures
(Score: 2, Insightful) by githaron on Friday February 28 2014, @06:11PM
If all the pollution is in one location, you can more easily and efficiently filter it. You can also more easily pick where the population occurs. City smog and air quality would become and issue of the past.
(Score: 2, Insightful) by hatta on Friday February 28 2014, @06:46PM
City smog and air quality are negligible compared to climate change. And no, you can't filter out the CO2.
(Score: 1) by githaron on Monday March 03 2014, @01:13PM
CO2 is not the only exhaust that comes from burning fossil fuels. It just happens to be the only one that anyone seems to ever talk about.
(Score: 1) by hb253 on Friday February 28 2014, @10:11PM
True, but from what I've read, intensive lobbying by the power industry has resulted in a weakening or delay of those stack scrubbing requirements.
The firings and offshore outsourcing will not stop until morale improves.
(Score: 2) by hemocyanin on Friday February 28 2014, @09:08PM
That's a good point but it doesn't solve the problem of widespread adoption, namely, limited range due to battery technology. This limited range issue makes electric cars a good choice as a spare car, but if a person can afford only one car, a not so good choice.
(Score: 5, Informative) by ls671 on Friday February 28 2014, @10:25AM
Somebody already got away with camshafts and even crankshafts a while ago. Pretty efficient too.
https://en.wikipedia.org/wiki/Wankel_engine [wikipedia.org]
https://www.youtube.com/watch?v=6BCgl2uumlI [youtube.com]
https://en.wikipedia.org/wiki/Mazda_Wankel_engine [wikipedia.org]
Everything I write is lies, including this sentence.
(Score: 3, Informative) by carburraetor on Friday February 28 2014, @10:43AM
Two stroke engines dont use camshafts as well, they use ports http://en.wikipedia.org/wiki/Two-stroke_engine [wikipedia.org]
I build models that rarely hold.
(Score: 5, Interesting) by c0lo on Friday February 28 2014, @11:14AM
And again, there was [wikipedia.org] and now is this one [wikipedia.org]
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by c0lo on Friday February 28 2014, @11:51AM
Here's a clip of how 1962-64 Chrysler Turbine Car sound [youtube.com] like (around 2'45" you can see it being driven)
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 1) by cwix on Friday February 28 2014, @01:02PM
Yes, but two strokes are notoriously inefficient, and polluting. You loose some of your fuel on the compression stroke.
(Score: 2) by Foobar Bazbot on Friday February 28 2014, @09:56PM
Two-stroke gas engines have those problems. But two-stroke diesels are very nifty -- a blower provides scavenging without crankcase involvement, and not injecting the fuel till you're ready for combustion means none gets wasted. (Most do have a camshaft and exhaust valve(s) for uniflow scavenging, but cross-flow scavenging is also possible.)
(Score: 1) by cwix on Friday February 28 2014, @11:23PM
Good point. I am actually not that familiar with two stroke diesels. I'm not even sure what the use case is for them. I will have to do some reading. Thanks!
(Score: 2) by Grishnakh on Friday February 28 2014, @04:19PM
Two-stoke engines are horrifically polluting and fuel-inefficient. They have very high power-to-weight ratios, however, and are mechanically simple, which is why they're frequently used for portable lawn equipment (weedwackers, leaf blowers, chainsaws, etc.). However, they've been banned from some municipalities because of the pollution, and 2-stroke boat motors have been banned from many places for the same reason.
(Score: 3, Interesting) by tirefire on Friday February 28 2014, @10:54AM
Still a very cool design, and it's a shame that Mazda seems to be the only company interested in it. I've never had the pleasure of driving an RX-7/8, but I've heard that unlike reciprocating piston designs, their rotaries run smoother the faster you rev them (downside: a rough idle).
(Score: 2) by Grishnakh on Friday February 28 2014, @04:26PM
Yep, and they also were notorious for having crappy fuel economy for the power they produced.
(Score: 4, Funny) by Vanderhoth on Friday February 28 2014, @12:43PM
You guys are totally ruining my day, I just spent two hours watching engine videos and now have two less hours to finish my stupid SOP and test case documents. Totally worth it.
Thanks, jerks.
"Now we know", "And knowing is half the battle". -G.I. Joooooe
(Score: 1) by monster on Friday February 28 2014, @04:41PM
Hey, at least there wasn't a link to tvtropes... In that case it would be game over!
(Score: 1) by epitaxial on Friday February 28 2014, @01:38PM
You do know that rotary engines need a teardown and rebuild much much sooner than piston engines? Fun fact: if you own an RX-8 they recommend you check your oil level every 3 gas fill ups. The engine burns that much oil.
(Score: 1) by Kromagv0 on Friday February 28 2014, @02:32PM
Well that was suppose to have been fixed with the RX-8 generation of rotary engine but they still couldn't resolve the problem with the carbon tips of the rotors lasting. This was a problem on the old RX-7 rotaries as well. It is an interesting design but it just never seems to deliver.
T-Shirts and bumper stickers [zazzle.com] to offend someone
(Score: 1) by computersareevil on Sunday March 02 2014, @02:11AM
Fact 3: No RX has had "carbon tips" aka apex seals since the early 1970's. The have been a steel alloy since at least the RX-3 introduced in 1972. They still use carbon apex seals in some VERY high-power applications, and yes, they don't last long. They've mostly been supplanted by ceramic apex seals.
Fact 4: The RX-8 engine doesn't die due to apex seal failure. The most common failure appears to be rotor side seal failure caused by excess carbon buildup in the side exhaust ports, which is caused by not revving the shit out of the engine daily. The RENESIS engine is the first Mazda rotary with side exhaust ports instead of peripheral ports.
Fact 5: The RX-7 never had a problem with apex seals. Normally-aspirated RX-7s routinely go hundreds of thousands of miles without problems (so long as they are properly-driven). The third-generation FD RX-7 didn't have problems with apex seals, it had problems with boost and fuel control. A cluster-fuck of vacuum hoses and solenoids controlled the sophisticated sequential twin-turbochargers. The cluster-fuck would spit a hose periodically, which would cause a sudden lean condition under boost, leading to catastrophic detonation and subsequently popping an apex seal. The apex seals are not the cause any more than a burned valve or punctured piston is the problem in a boosted piston engine that goes lean. Securing the cluster-fuck of hose ends to their fittings with cable ties solves that reliability problem.
In summary, pretty much all the reputation problems with the Mazda rotary engines amount to FUD, which makes it all the more painful to read it being spread by (supposedly) fellow geeks on SN.
(Score: 1) by computersareevil on Sunday March 02 2014, @01:53AM
Wrong. I own a road-race-track-driven 2005 RX-8 with 70k miles on it, no rebuild yet. Many are over 100,000 miles without a rebuild.
What happens to the Mazda rotaries that shortens their life is that ignorant people like you don't read the owner's manual or look up basic facts about the engine, abuse and neglect it, then bitch when it dies on them.
Fact 1: "Oh, it burns the oils!" The Mazda rotary burns oil on-purpose. This is how it lubricates the apex seals. This is how it's been since the Mazda Cosmo Sport 110S [wikipedia.org] was introduced in 1967. And yet here we are 46 years later and people still can't get it through their soft skulls that it burns oil on-purpose.
Fact 2: Properly maintained and driven Mazda rotaries will go hundreds of thousands of miles. I also race a 1985 Spec RX-7 with 167,000 miles on the engine. They aren't really "broken-in" until they are over 100,000 miles. The secret is that if you drive it like a piston engine, you will ruin it. Everything in a rotary should be done at least 2X the RPM of a piston engine. It should be redlined at least daily, if not at every shift pulling away from a stop. That doesn't mean drag race it at every light, it just means don't shift until the little buzzer lets you know that 9000 RPM has arrived and you should shift when you get around to it. The buzzer is the only way you'll know this buttery-smooth little engine is turning that fast. People who regularly drive under 2000 RPM and never shift over 6000 will kill the engine in under 50k miles.
(Score: 1) by Kromagv0 on Friday February 28 2014, @02:38PM
The best thing the rotary engine has going for it is the higher specific output since it is much closer to a 2 stroke than a 4 stroke otto cycle engine. There was suppose to be some wonderful efficiency gains since there were so few moving parts but they typically have been over stated. Also add in the wear and premature failure of the carbon tips that has plagued Wankels from the beginning and it is a niche product. They are a nifty little engine none the less and I applaud Mazda for trying to perfect them.
T-Shirts and bumper stickers [zazzle.com] to offend someone
(Score: 3, Interesting) by frojack on Friday February 28 2014, @07:45PM
Come on guys, a subject of hmmmm just makes you look dumb. Don't type like you talk.
Wankel was a good try, but it still wasted a lot of energy, and emitted too much un-burned gas.
The problem was getting the porting just right wasn't feasible other than for a very limited range of RPM.
Frankly, this new air-operated system seems interesting, but the use of air is imprecise, and inefficient. Air is compressible, and about 30 percent of the power applied to air actuators (of just about any sort) goes to just compressing the air to working pressure. Then you have to vent that built up pressure when you want the valve to close again.
Hydraulic would seem much faster, and more precise way of moving the valve stem. Electric valving of the Hydraulic fluid would allow computer controlled adjustment for timing. Hydraulic chambers for both Raise and Lower could eliminate valve springs as well, meaning the engine wouldn't be wasting energy compressing a spring.
(Note: Hydraulic lifters as used today are simply a buffer between cam shafts and valve stems, so not the same thing).
No, you are mistaken. I've always had this sig.
(Score: 4, Informative) by Ellis D. Tripp on Friday February 28 2014, @01:00PM
when the SAE and automakers were considering a shift to 42V electrical systems in cars. In addition to shrinking the size/cost of wiring harnesses (higher voltage = lower current = thinner cheaper wires), the higher voltage would have made it practical to runs some larger loads such as A/C compressors and power steering electrically, rather than via belts from the crankshaft. The higher voltage would also have made it possible to use solenoids to actuate the intake and exhaust valves, removing all the frictional losses in the valvetrain, and allowing for simple variable valve timing for improved performance and emissions.
Unfortunately, it was soon discovered that switching 42VDC is a lot harder than switching 12V. Switch and relay contacts quickly eroded, and power semiconductors at the time were expensive and barely up to the task. So the 42V initiative was quickly forgotten.
"Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!"--Edward Abbey
(Score: 3, Informative) by carguy on Friday February 28 2014, @01:59PM
Even before the unsuccessful 42V initiative (good memory Ellis!), there were various attempts at camless valve operation. We were in contact with Moog about 1990 when they contributed to the Lotus effort [wikipedia.org]. There were running engines built although they were limited to a relatively low ~3000 rpm. I believe that there were versions with both electro-hydraulic and electric actuation. One of the important uses for these test engines was as a simulator to quickly test different valve timing, without the need to machine new cams.
Programmable valve timing can also remove the need for the throttle -- just open the intake valve a tiny bit for idle. But there is something reassuring about a throttle plate that can be closed to control the engine -- throttles are missing in Diesels, which have been known to run away if the fuel control jams on...
The peak power required to move a poppet valve for a high speed engine is not trivial. A roller cam is actually fairly efficient because the energy stored in compressed springs is returned (mostly) to the cam when the valve closes.
Were any other readers involved in similar programs at other manufacturers? There are many clever people in automotive R&D and camless engines became a hot topic as soon as realtime computer control was in reach.
(Score: 3, Informative) by Grishnakh on Friday February 28 2014, @04:32PM
But there is something reassuring about a throttle plate that can be closed to control the engine -- throttles are missing in Diesels, which have been known to run away if the fuel control jams on...
That's not a problem.
The reason it was a problem on older diesels is because, back in those days, they used mechanical (engine-driven) fuel pumps. The fuel never stopped flowing until the engine stopped, or the tank ran out. On modern vehicles, this isn't a problem; if you want your engine to stop and it's "dieseling", you just turn off the electric fuel pump. It won't be instant that way, but it won't take very long because fuel pressure will drop quickly.
We were in contact with Moog about 1990 when they contributed to the Lotus effort. There were running engines built although they were limited to a relatively low ~3000 rpm.
I remember reading about a test engine like this back around 1992 in an academic magazine. They said at the time that the power required for the solenoids was really high. I never heard again of any such attempts.
(Score: 2, Informative) by drussell on Friday February 28 2014, @10:33PM
Yes, it's still a problem, and is the reason that many larger diesels (esp. stationary engines) have emergency air shutoff damper valves.
The burning of the diesel fuel (which can be halted by the electric fuel pump shutting off, some kind of mechanical fuel valve closing or even emergency hack to the fuel line with an axe) isn't the only possible cause for a runaway. It is true that if your rack hangs open or some other type of main fuel system failure causes the runaway, the regular fuel cutoff / anti-run-on device should cause the engine to stop when the key is turned off.
The more common reason for a diesel runaway, especially on turbo diesels, however, isn't fuel, it's engine oil. Whether it's pulled in due to a worn engine, overfilled crankcase, cracked block/head or most likely on a turbo, failure of a turbo shaft seal spewing engine oil into the intake side. The engine is now running on the crankcase oil instead of diesel. Shutting off the key won't help and there's many, many times more than enough oil in the crankcase to destroy the engine before it runs out.
The only surefire way to stop a runaway diesel is to block the air supply. This can be done either by covering the air intake completely with a book or block of wood or whatever, (usually only practical during service with easy access and air cleaner removed) or better yet, simply blasting the air intake area with a CO2 type fire extinguisher (NOT a dry chemical one, that would destroy the engine!) until the engine stops. Works like a charm. Most people who work on diesels know to have a CO2 type extingisher right handy in the shop, always ready for this purpose.
Personally, if I had a diesel vehicle, I'd carry one with me, just in case. (I have dry type extingushers in my vehicles, but if I had a diesel I'd have a CO2 for it also as well!)
(Score: 2, Interesting) by dublet on Friday February 28 2014, @01:52PM
Notably the Renault F1 team has used pneumatic valves for a while: http://scarbsf1.com/valves.html [scarbsf1.com] There was at least one race last year where one of the Lotus F1 team's cars piloted by Grosjean had a pneumatic fault. They even tried refilling the air in the car.
"If anyone needs me, I'm in the angry dome. [dublet.org]"
(Score: 4, Informative) by carguy on Friday February 28 2014, @02:05PM
> Notably the Renault F1 team has used pneumatic valves for a while ...
F1 engines use pneumatic valve springs, but they still use mechanical camshafts.
(Score: 1) by dublet on Friday February 28 2014, @05:27PM
Down in flames I go..
"If anyone needs me, I'm in the angry dome. [dublet.org]"
(Score: 1) by hb253 on Friday February 28 2014, @10:07PM
Hold on there, before you crash...
I knew I read something about BMW doing this years ago. Anyway, I found this article from 2003 on the NY Times site.
http://www.nytimes.com/2003/08/21/technology/circu its/21next.html [nytimes.com]
Note that the prototype was built in 1999. Here's a snippet from the article:
The firings and offshore outsourcing will not stop until morale improves.
(Score: 1) by gmby on Friday February 28 2014, @01:55PM
thinking about this very thing in my young engineering days. Also this is not new. It have been done many times before; but has proven to be failure prone. Think about how often your injectors and such fail; then multiply that by 2/4 valves.
Also this is just the kind of thing SN is best for.
Gordon
Bye
(Score: 1) by Kromagv0 on Friday February 28 2014, @02:28PM
Well fuel injector failures seem fairly rare now days unless your run some crappy fuel through them. I have had 6 fuel injected vehicles so far and have driven about 370,000 miles between all of them and never replaced a fuel injector. None of the vehicles were new when purchased and as far as I know none had an injector replaced before I got it. As far a total miles on all of those vehicles it probably is around 1,350,000 miles (like I said I get used vehicles) and there were a total of 36 fuel injectors. So it would seem that a fuel injector is fairly reliable but this may be some selection bias since by the time I get a vehicle it is usually a survivor but given how mechanical things fail (wear) it should be that I would be more likely to have to deal with a failed injector.
I would imagine that moving to similarly controlled intake and exhaust valves would be similarly reliable which would mean that for most people they wouldn't have to replace them during the average lifetime of the vehicle. And if you do have to replace the actuator it would be much simpler than replacing a cam, timing chain/belt, rocker arm, or valve on an existing vehicle and instead would be more like replacing a spark plug in a coil on plug setup on some vehicles.
T-Shirts and bumper stickers [zazzle.com] to offend someone
(Score: 1) by epitaxial on Friday February 28 2014, @02:56PM
Fuel injector failures are pretty rare. I've never seen one go bad, my last car had over 250,000 miles before I scrapped it. I'll gladly take an easily replaceable actuator over a camshaft or valve that requires an engine teardown. The fuel economy savings alone would be worth a possible repair.
(Score: 1) by Kromagv0 on Friday February 28 2014, @03:07PM
Since this is vehicle tech that isn't about the stupid infotainment system it seems on topic to me. Besides an advancement in the Carnot Cycle efficiency of a heat engine is always welcomed.
T-Shirts and bumper stickers [zazzle.com] to offend someone
(Score: 0) by Anonymous Coward on Friday February 28 2014, @03:07PM
What is the source for the efficiency improvement? Getting rid of weight and friction of driving camshaft?
(Score: 1) by Gryle on Friday February 28 2014, @03:17PM
I'm not a mechanic but I'm guessing the improved torque means less fuel used per stroke, leading to more efficient fuel consumption. Though you're probably right in that shedding weight probably helps too.
Ignorance can be remedied. Stupid seems to be a permanent condition.
(Score: 3, Interesting) by Ellis D. Tripp on Friday February 28 2014, @03:24PM
Reducing frictional losses in the valvetrain is part of it, but the bigger part is being able to adjust valve timing dynamically in response to changing RPM, engine load, charge density, etc. to maintain optimum efficiency under all operating conditions.
With a camshaft, you are stuck with whatever timing and lift pattern is ground into the lobes.
"Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!"--Edward Abbey
(Score: 2) by Grishnakh on Friday February 28 2014, @04:37PM
With a camshaft, you are stuck with whatever timing and lift pattern is ground into the lobes.
No you're not. Car engines have been employing variable valve timing for a couple of decades now. Honda's VTEC was one of the early ones; it basically had two cam profiles on each camshaft, and could switch between the two, so one set of lobes was optimized for low rpm, and the other for high rpm. Other engines have variable phasing: the position of the cam can be changed at different rpm. There's a lot of different versions out there today, which is one reason why engines in today's cars are getting such great fuel efficiency and horsepower numbers.
(Score: 1) by VanessaE on Friday February 28 2014, @04:55PM
(Score: 4, Informative) by Grishnakh on Friday February 28 2014, @05:45PM
Right, but the point is, unlike older engines where you're stuck with a single profile and timing at all engine speeds, with newer engines you can change the timing/phasing, and/or the lift profile. No, it's obviously not as flexible as solenoid-actuated valves, but it's a big improvement that probably gets you most of the benefits. (Honda's VTEC only gives you two profiles, low and high, whereas the variable cam timing gives you variability across the rev range, though no lift change ability, but I'm pretty sure the newest engines (probably in more expensive cars like the 370Z) give you both now.)
(Score: 1) by tirefire on Friday February 28 2014, @04:43PM
Indeed. I'll bet the home garage tuner crowd would much rather change the settings on the valve management computer than buy and install a high-performance camshaft (which runs $1000+ IIRC).
(Score: 0) by Anonymous Coward on Friday February 28 2014, @05:04PM
the problem is that a camshaft has a fixed profile. ... or something ...
it will always open the valves the same way. it doesn't matter if you're idling at
a red light -or- overtaking on the highway.
without a camshaft controlling the valve timing but instead have a completely independent system
it means you can really "play piano" : )
you can open the valves just a 'lil at the idle red light and open them longer (get more air in) when
overtaking
also kids will probably start sharing "valve-profiles" and flash 'em to their cars : )
(Score: 1) by osiguru on Friday February 28 2014, @05:37PM
Efficiencies will be vastly improved through precise valve timing, and the reduction of parasitic drag.
Spinning all of the camshaft hardware off the face crankshaft (cogs and pulleys) significantly reduces the total amount of combustion energy delivered to the rear of the crankshaft. The rear of the crankshaft connects to the stuff that moves things like torque converters, and gearboxes and the sort.
This is why we have belt/cog systems in modern cars now instead of chains and sprockets.
(Score: 2, Interesting) by js on Friday February 28 2014, @09:58PM
So for car stories do we need an obligatory computer analogy?
(Score: 2, Interesting) by NovelUserName on Friday February 28 2014, @10:36PM
Its interesting to me because they selected pneumatics rather than hydraulics. I had always understood that the compressibility of air made pneumatic actuators problematic for high precision or high speed applications. At the speeds you need to actuate valves for normal ICE operation (~=6KHz) I would have told you that the problem of modeling how the air flows around your valve as it opens and shuts would make your control problem nightmarish- especially if you want to have your valve open and close on a specific profile rather than just popping open and shut as fast as possible. This implies either some very dedicated testing or a quite clever control system.
On to my main point:
I'm skeptical of the claims of a 50% efficiency gain. The camshaft generates nowhere near that much drag, and you still need to power the pneumatic system, which the old motor doesn't. Most of this putative gain then has to come from being able to adjust the valve timing and lift dynamically.
I can only assume the following: A conventional engine could match (or nearly match) the power output of the demonstrated pneumatic system. A conventional engine could match the efficiency. But the same engine could not do both. By picking some arbitrary middle point for the conventional engine performance you appear to have simultaneously wildly improved power and efficiency, when really an ICE that's well designed for it's use case will be competitive with the pneumatic system in either power or economy.
The other point is that small cam-actuated engines are making HUGE gains in efficiency and power output lately. Ford for instance has a 1L motor that puts out 300HP, and ( in a racing car anyway [youtube.com]) will do 100MPG. I very much doubt that simply dropping this pneumatic system on top of that motor will result in 390HP and 150MPG from the same motor.
(Score: 1) by demonbug on Friday February 28 2014, @11:47PM
First, valves generally only switch twice per full cycle - intake valves open and close on the intake stroke, and remain closed for the remaining three strokes (in a 4-stroke). With two strokes per rotation (so two rotations per full cycle), you're only looking at 3,000 cycles per minute at 6,000 RPM, or ~50Hz (rather than 6KHz you stated).
As for the efficiency gain, it is less about drag and more about timing. Depending on throttle position, engine speed, intake pressure (boost), and probably an assortment of other variables, the valve lift and timing are going to vary widely for maximum power and/or efficiency. With variable timing from using different cam lobes (or sculpted lobes to allow more gradations) there is some variability available to engines, but nowhere near the same range as this would offer - there just isn't a practical way to program all that into an analog camshaft. Plus, on the efficiency end, you would be able to just seal off whatever cylinders you don't need at the moment - and you could even vary rotation by rotation which cylinder is shut down to spread wear evenly and improve balance.
That said, their 50% number does seem pretty high; but maybe they are comparing to an ICE with fixed valve timing and port fuel injection. Combine the infinitely variable valve timing and lift with direct fuel injection, and I can easily see that 50% increase in efficiency.
(Score: 1) by NovelUserName on Sunday March 02 2014, @03:03AM
Well, that's embarrassing- On top of forgetting that the valves don't actuate each cycle, I made the elementary mistake of forgetting that minutes aren't seconds when converting RPM to Hz.
Thanks for pointing that out!
(Score: 1) by mrkaos on Saturday March 01 2014, @02:30AM
and to me because they chose those over electromagnetic.
I'm not, though this is not a criticism of your point, just that ICE are so damn inefficient that improving them is a matter of picking what you want. The induction of the system is a big place to do this and it's not a matter of drag but one of *volumetric efficiency* or VE.
A cam is only efficient in a very narrow band of RPM and timing the opening and closing of valves dictates the VE of the engine. So with a cam your valves are open for the same relative duration or RD (in percentage terms to the length of the stroke) at any RPM. What this mean is that engines with a cam has a great power range for a limited RPM.
However, you need the opposite characteristics to have the power band cover the entire rev range. At low RPM the valves short be open for a shorter RD and for higher RPMs a higher RD. There are also post-combustion things you can do so more air is available for the next combustion cycle. This, in a nutshell is why it's possible to start to attain better efficiency in an engine with a system like this.
Also you are able to shut down cylinders that you don't need during cruise, so you use less fuel. Ahhh we do that now with engine management systems - which is true except that what they don't do is shut down the 'compression' cycle and power is lost there.
Many of the efficiencies won't be *ahem* driven into ICE designs without radical new EMS, but apart from being disappointed that my own design will probably never see the light of day, this is a great step forward.
My ism, it's full of beliefs.