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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: 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.