Behold the cam-less future
Mechanically actuated valves may soon be a thing of the past. We've made over a century's worth of improvement on the same basic combination of a camshaft, followers (or lifters), a poppet valve and a spring. We've gone from using pushrods and rocker arms to actuate the valvetrain to direct-acting buckets motivated by an overhead camshaft with variable phasing and lift. While engineering ingenuity has managed to wring incredible performance and flexibility out of these setups, there's only so far you can go before bumping into the laws of physics. French automotive supplier Valeo SA has been working on camless engine technology for quite some time and they expect to have their system on the street by 2010 or 2011. Valeo is working with several automakers to implement the camless technology. Eliminating a traditional valvetrain is expected to yield efficiency improvements nearing 20 percent. An increase in performance and emissions decreases will also be realized from the system.
More after the jump
[Source: Valeo via Autoweek]
The Valeo system uses electromagnetic actuation. Where a typical valvetrain uses a spring to hold the valve closed until the camshaft lobe overcomes the spring, the camless system uses a pair of springs, and the valves default to a partially open position. There's a pair of electromagnets above the valve assemblies with an armature in between. The armature is what the electromagnetic fields move to actuate the valve. The upper electromagnet pulls the valve shut, and the lower electromagnet fully opens the valve. This system eliminates entirely the camshaft and its associated drive system such as belts, tensioners and bearings. High performance engines with variable timing and lift valvetrains will be easy to accomplish with the Valeo system, as opposed to the complex mechanical systems currently used to accomplish those functions. Think of Valeo's system as operating much like a fuel-injection system. Each valve event can be discrete and optimized. Low end torque will be increased, and cylinder head design can use more radical valve and port angles without having to fit rotating machinery above and around the cylinder head. Depending on the size of the hardware, packaging could approach the compact size of pushrod engines.
Think of it, your engine could switch run in the Atkinson cycle with cylinders deactivated at cruise and save a lot of fuel, switching over to the traditional Otto-cycle and all cylinders when more power is needed would be fast and seamless. While some engines can currently pull off cylinder deactivation, they can't switch cycles from the more fuel-efficient but less powerful Atkinson Cycle (or Miller-cycle when teamed with forced induction) and the "standard" four-stroke cycle. The biggest stumbling blocks for Valeo to overcome are developing sensors that are accurate and durable enough to make sure valve events occur exactly when they should and the system has a reasonable MTBF. Cost of the system will likely see it installed on premium and performance vehicles at first. Valeo has a "half-camless" configuration that offers eighty-percent of the benefit at half the cost of the full-camless system. We're excited to see this system hit the street. We're even more excited to see what the DIY aftermarket can do with this hardware - just imagine, a "camless retrofit-kit" for your classic car. You build and program the system, much the same as a MegaSquirt. That'd be great under the rear decklid of the Porsche 912 I lust for.
Reader Comments (Page 1 of 2)
dreesemonkey 1:54PM (12/22/2006)
That's extremely cool. I wonder what kind of performance gains there are just from the crank not having to turn the cam(s), and what that means. You'd think it could have higher-rpm applications, but there will obviously be a limit to how fast these things can operate.
Very cool though, I love exciting technology like this :)
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Car videos & Motorcycle videos 1:58PM (12/22/2006)
With significantly less and lighter moving parts we are sure to see more power and fuel efficiency. One major feature with these engines will be the ability to rev higher RPM's.
http://www.dpccars.com
DPCcars
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thesawzall 5:41PM (12/22/2006)
I love the idea of software controlling the valves. It leaves a lot of room for customization.
But, last time I read about this kind of technology, they had problems ensuring reliability as the valves slammed home at the end of their opening and closing. Since camshafts are somewhat circular, the speed of the valves slows as they reach the end of their travel.
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Kansei 2:13PM (12/22/2006)
Mazda has been doing the camless thing forever..
wankel rotary ftw :D
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PuffyC 2:15PM (12/22/2006)
Man, how many years now has the camshaft been marked for termination? 10? 20? 30? I've lost count of how many articles just like this that I've read over the years but we're still using camshafts like we always did. Maybe this will be different but I'm not holding my breath.
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cowboy bob 2:40PM (12/22/2006)
I'll be in a box before this is for real. Same for hydrogen fuel cells, widespread ethanol fuel, or bio-diesel. The truth is that the future will prevail, but the time it takes for it to get here is like the travel time to the stars. Just not in my lifetime. Meanwhile, I need to make motormounts for my hot rod.
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Bob_Ericson 3:36PM (12/22/2006)
As a dyed-in-the-wood France basher, they have always earned my respect with regards to cars. These guys always come up with innovative and amazing technologies. From Peugeot's 6 valve shocks (best in the world) to Citroen's hydromatique suspensions to Renault's F1 pneumatic valves that allow for unheard of RPM levels, French cars are like none other. I only wish PSA would make a real effort to re-enter the US market with zeal.
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chewy 3:38PM (12/22/2006)
They stole my idea. This should allow for infinite valve timing and possibly less losses on the valve operation when comparing to a cam.
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VW-Guy 4:15PM (12/22/2006)
Excellent! I remember reading about something similar about a year ago. It's coming - it may take awhile to work out the details but it's coming. Lighter weight, less drivetrain canabalism, better performance and mileage. What's not to like?
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davidl340 3:48PM (12/22/2006)
Electronically controlled valves can't come soon enough, the possibilities would be awesome.
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BOB 3:55PM (12/22/2006)
GEE-- HOW DO YOU RUN THE CAR WHEN THERE IS A MAJOR ELECTRIC POWER OUTAGE, LIKE WE GET IN THE SUMMERS, SOMETIMES??
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Nick 9:53PM (12/22/2006)
You are joking, right Bob?
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mulad 4:22PM (12/22/2006)
I dunno Bob, if you're worried about that, then I'm interested to know how your extension cord is holding up these days...
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Jason 4:58PM (12/22/2006)
What car company DOESNT have a decade-old project for an electromagnetic valve system?
The problem is not do-ability, it's cost.
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andyduncan 5:54PM (12/22/2006)
Thesawzall:
Thank you, I was wondering what the dual springs were for, but after reading your comment I think I might have an idea: Since the 'natural' state of the valve is neither open nor closed, the springs would act to slow the progress of the valve as it got towards it's start and end points, much the same way as the cam lobes do now.
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dave 11:53AM (12/23/2006)
the french come up with this kind of technology? do they forsee a war in the future that they have to retreat from faster?
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gary 8:00PM (12/22/2006)
I think if this technology had any merit F1 engine manufacturers would have utilized it years ago.
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ninad 10:46PM (5/28/2007)
they did, renault had a similar system a few years ago, and it worked fine, i think they discontinued it because the improvement in performance didn't justify the increase in weight.
gbh 9:15PM (12/22/2006)
Pneumatic valve actuation has been used many times over the last several years on race cars.
Now that the computing power to control them is cheap enough, it really is only a matter of time.
We've know it was coming to the mass market for the last 20 years, tightening regs and desire for more performance per cubic inch will make it happen.
Belt driven water pumps, separate starter/alternators, belt driven p/s pumps, all this stuff is primitive tech that will have to go eventually.
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Joel 12:34AM (12/23/2006)
andyduncan:
Podcast Auto (in their 1/5/06 episode, at around the 41 minute mark) mentioned that dual springs are used to reduce valve float brought about by resonance. Having two springs with different natural harmonic modes ensures that at least one of them will be operational at any given RPM.
gary said: "I think if this technology had any merit F1 engine manufacturers would have utilized it years ago."
F1 engines use pneumatic valve actuation, which allows up to around 20,000 RPM. But in F1, cost is a minor consideration, whereas in consumer use, it is extremely important. Perhaps the electromagnetic valve actuation provides a better cost to benefit ratio. Or maybe we'll just end up with something like Ducati's desmodromic valve system.
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