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Scientists Claim Major Leap in Engine Design
An anonymous reader writes "Purdue researchers say they have made a major advance in the design of the internal combustion engine, one that could seriously boost fuel efficiency and cut emissions. A key portion involves building intake and exhaust valves that are no longer driven by mechanisms connected to the pistons, a departure from the way car engines have worked since they were commercialized more than a century ago. 'The concept, known as variable valve actuation, would enable significant improvements in conventional gasoline and diesel engines used in cars and trucks and for applications such as generators, he said. The technique also enables the introduction of an advanced method called homogeneous charge compression ignition, or HCCI, which would allow the United States to drastically reduce its dependence on foreign oil and the production of harmful exhaust emissions. The homogeneous charge compression ignition technique would make it possible to improve the efficiency of gasoline engines by 15 percent to 20 percent, making them as efficient as diesel engines while nearly eliminating smog-generating nitrogen oxides, Shaver said.'"
Are they going to do anything useful, like, say, actually boost milage? Or are they going to continue what they've been doing and just increase horsepower and torque?
But they don't actually talk at all about how they WILL drive the cams. And for that matter, they still have cams! Driving valves with solenoids somehow would be more meaningful. If they're keeping the cam, then they can have variable timing easily enough, but they're still going to need a bunch of additional hardware to control lift and duration. Of course, it takes a lot of power to use solenoids to drive the valves, which is why they're not doing it now. Personally I'm far more interested in Coates rotary valves, which have been used in racing. They let you raise RPMs dramatically without having an exploding valvetrain. Combine that with direct injection and I'll be pleased as punch.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Yeah, mechanical valve actuation has its problems. It makes for either non-optimal valve placement (standard wedge heads) or overly complicated mechanical actuation trains (see Chrysler original Hemi engine design). So a better method to actuate valves than driving it from a fixed, or fixed-variable, design could make for better engine performance overall. That's hardly new. As best I've seen, this has been merely an engineering problem to determine a better way to actuate valves that meets the requirements of cost, durability, cost, performance, and cost -- when it comes to consumer engines. While such an actuator method is certainly significant news in and of itself, it's not like someone has redone the whole engine.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
The problems with batteries are that they have poor energy density (even the theoretical energy density of a chemical battery is less than that of gasoline) and that they take a lot of energy to produce. They also tend to be based around substantial quantities of toxic, polluting materials; the refinement of those materials is further detrimental to the environment. Fuel cells with liquid fuels produced by nuclear, solar, wind, hydro, or biofuels (or taking biofuels directly) do much better along potentially all of these lines.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
You missed my point. I wasn't criticizing SUV owners so much as questioning the assumptions and motivations behind our (yes, mine too) conspicuous consumption. Just as easily could have used jewelry or oversized houses as examples. The point is that we don't attract nearly as much favorable attention when we buy stuff like that as we think we do, so maybe we're wasting our money in addition to whatever other harm we may be causing.
Kudos on the bike anyway, though...
This article, as has been, and will be, pointed out throughout the comments is not news, very interesting, or likely to yield much of practical value.
..., reduce the number of humans by 6 billion, or so. Unless you do that, nothing else will matter. Additional terrestrial hydrocarbon fuel resources are becoming quite hard to reach and there's too much demand to get by easily on biological sources alone. Improving the efficiency by which we use the fuel helps us, regardless of the other issues.
Non-crankshaft-linked valve timing, whether through variation mechanisms that are in current street car use, or electric/pneumatic/hydraulic actuators, such as the F1 engines have used for years do not solve the problem of heat control. Burning fuel (which is why some parts of the combustion chamber are hotter than others; get a clue) generates heat. Some of that heat expands gases to push pistons (or rotors) and a lot of heat raises the temperature of the engine components. Without cooling the engine, the accumulated heat destroys the materials. This is why my air-cooled Ducati engine has a lower power output than the water-cooled Ducati engine of the same (roughly) displacement. The water-cooled engines can keep the components at a lower (and more consistent, I know) temperature, so they can use more air and fuel to generate more power (the extra valves are only usable because the additional heat can be managed).
The real solution is to use more of the chemical energy to provide power for moving the vehicle and less of it to heat the components. Trying to store the energy in rechargeable batteries will result in mostly short-range urban and novelty vehicles for a very long time, since the energy density of the storage, both in mass and volume, and recharge rate are pathetic compared to diesel, gasoline, or compressed propane/methane.
The "hydrogen solution", applied as an internal combustion fuel, has the same problems, plus the additional headaches of generating the hydrogen ("but solar is cheap" - and it will compete directly for surface area with homes, farms, and the large-scale installations needed to power your iPod's recharger since we'll be trading power between sunlit and darkened regions) and transferring it between fuel station storage and vehicle storage. Hydrogen fuel cells, still with the generating, storage, and transfer problems, are pretty good at converting between chemical and electrical energy, and electric motors are usably efficient at converting electrical energy into motion.
What we need are fuel cells that can handle ALL of the chemical energy in a hydrocarbon fuel, converting not just the stored hydrogen and oxygen from the air into water (2 H2 + O2 = 2 H2O; put energy in to break up the hydrogen and oxygen molecules then get energy back by combining the hydrogen and oxygen atoms into water), but also using the carbon atoms in the fuel molecules to make CO2 which gives a larger net energy output by mass of fuel.
As for "CO2 is a greenhouse gas": So what? We're already too far down the path. The paleohistoric record of ice-age cycles shows that we have already passed the inflection point to cooling while we're accelerating the heating. If you want to reduce the CO2 footprint of humans, along with ending overfishing of the oceans, sucking the deep aquifers dry, destruction of the rain forests for farmland, habitat destruction for either human use or by diversion of fresh water resources, pollution by agricultural runoff,
I'm a complete idiot when it comes to car repair, but in 1976 I replaced the head gasket on my Oldsmobile Rocket 350 V8 with a couple of adjustable wrenches. Super easy to work on.
I remember when the heater core went -- no sweat, pull the hose off the heater core input, plug it back into the block, done deal. Six months later when I had the money I pulled the heater core and replaced it.
Front bearings need to be repacked? Piece of cake. Just don't forget the cotter pin that holds the whole damn wheel on, and you're good to go.
Car was unbeatable in a straight line. Handled like crap otherwise, though, but who cared. Nothing like a 350 with a racing transmission and a 4 barrel off the line, baby.
Nowadays, I open the hood and it's a sea of hose assemblies and pipes, can't even see the block. If you buy the shop manual, you find out the first thing you need is a zillion-dollar set of metric torque wrenches before you even start. Screw that.
Then the solenoid went on my Honda Accord, and I found out you can't buy a solenoid any more. You have to buy the whole "alternator assembly" which includes alternator, solenoid, voltage regulator, and God knows what else -- to the tune of $400. I came THIS CLOSE to ripping the goddamn "alternator assembly" apart and fixing the solenoid myself, except I actually have to work for a living. So frustrating.
To me, modern vehicles are eminently more reparable than the old ones, but that's because I'm an electronics geek I suppose. Because the thing is mostly fly-by-wire, it's dead easy for me to go in with a laptop and dump the codes to figure out what's wrong with the system.
Take for example my friend's VW Bug... Engine was running rather roughly, and showing the "check engine light". Plugged in my laptop, dumped the codes, and one of the diagnostic codes was showing a vacuum line failure. Sure enough, we replace the appropriate vacuum line, engine runs fine after that. Sure, a seasoned mechanic would probably have figured that one out immediately, but to an office geek like me, the electronic diagnostics were a godsend.
The primary difference between modern vehicles and the ones from the days of yore is that there is a different skill set required to work on them. Now, on top of being able to turn a wrench, you need electronics and computing experience.
...si hoc legere nimium eruditionis habes...
Because it endangers me more, it frustrates me more, and pisses me off more.
(note: I mentioned women because this is a recent, real-life experience for me. I am in no way implying that men don't do the same thing...)