Valeo In Development Contracts for Camless Engine; Projections of Up To 20% Improvement in Fuel Efficiency
21 December 2006
|Valeo’s camless Smart Valve Actuation technology. Click to enlarge.|
AutoWeek reports that Valeo SA has several development contracts with automakers for its camless engine. Although Valeo would not confirm the contracts, a spokesperson said the supplier is working with several global automakers on camless engines.
Camless technology is projected to deliver as much as 20% better fuel economy over a conventional engine.
Valeo presented its camless Smart Valve Actuation (SVA) at the 2005 Frankfurt Motor Show. In a camless engine, each engine valve is operated individually by an actuator that is placed on the upper surface of the cylinder head, directly above the valve guides. Each actuator is linked to an engine-mounted Valve Control Unit (VCU) that ensures the optimal positioning of all valves and performs the power drive function.
The SVA system thus replaces the conventional mechanical cam belt, camshaft and hydraulic cam followers.
By controlling residual gases, minimizing pumping losses and deactivating cylinders and valves, this technology reduces fuel consumption and pollutant emissions by up to 20%. Consumers will also benefit from enhanced performance and driving comfort, due to an increase in low-end engine torque.
Valeo is working on two different camless systems, each one including the actuators, the Valve Control Unit (VCU), the wiring rail and the Electronic Control Unit (ECU) with the specific strategies dedicated to these new concepts.
The “full-camless” system manages the valves on both the intake and exhaust side of the engine. The “half-camless” system manages the inlet valves only.
Martin Haub, Valeo board member for R&D, told Automotive News Europe that Valeo is focusing on the half-camless system, which delivers 80% of the performance of the full-camless system, but at half the cost.
(A hat-tip to Patrick!)
They are projecting that the "half cam" version can be mass-produced for around $400 more than the standard cost for a gasoline engine.
Posted by: Patrick | 21 December 2006 at 01:12 PM
This might give start from stop systems a run for their money. Similarly for GM version of the 2mode hybrid. On the flipside, 2mode offerings from BMW or Mercedes Benz may offer both the camless valves, and hybrid powertrain. Combined with DI, and a few other features, they may be able to offer 4-5 sec 0-60mph, with 30-35mpg, in a C or D size car.
Posted by: allen_z | 21 December 2006 at 01:25 PM
Am I the only one who read this article and practically yelled out loud, "Where the hell was this idea 20 years ago???"
I know--getting even a "simple" idea like this to work properly under all conditions is likely quite a challenge. Regardless of the details, this technology could be retrofitted onto existing engine designs with enormous benefit.
Posted by: Lou Grinzo | 21 December 2006 at 01:30 PM
20 years ago, reliable microcontrollers with the processing capability (I imagine the sensors with finite enough "sensing" relies on 32bit DSP), accurate digital sensors, and low cost electronics did not exist. I may be mistaken but I believe it still requires a 42V electrical system (which is much easier to convince an auto maker to deal with today given the prevalence of micro, mini, and full hybrids and the pressures around the world for greater fuel economy).
Posted by: Patrick | 21 December 2006 at 01:45 PM
Good idea! Wondering, though, what would be the electrical demand from the entire system? Would the gain in fuel saving offset the greatly increase in electrical demand from all these huge electro-magnets that can generate over 100 lbs of force?
In a conventional cam-actuated valve train, the work done required to overcome the valve spring to open the valve will be returned back to the camshaft when the spring forces the valve to close, thus the spring act as an energy storage device. Friction in the valve train is the only source of power loss.
Is there provision here to capture the EMF generated when the armature is returned back to the closed position from the energy stored in the spring, hence reducing the electrical demand on the system? If so, then the resistive loss in the electromagnet winding may be no more than friction in the valve train of a cam-actuated valve system.
Posted by: Roger Pham | 21 December 2006 at 02:02 PM
I know of one customer. Mercedes-Benz AG. They are using it in their 2 liter I4 KDI (kmopressor direct injection) debuting on the C-class. Can't wait to see what the fuel economy will be.
The really big boon, other than fuel economy, will be the ability to tune the power curve. The ability to do basically whatever you want to with valve positions gives one the ability to have a very flat torque curve. I wouldn't be surprised if BMW and Porsche are the next ones to pick up this technology.
As time goes on and production is ramped, I'd imagine that this technology will be less expensive than traditional cams. Why? Not as much time tuning/engineering cams to survive vibrations and achieve a specific power curve.
Posted by: John | 21 December 2006 at 02:16 PM
Patrick, the 100lbf is required to keep the cam in contact with the roller or rocker arm contact, when the cam goes away most of the forces go with it. The compressive force from the piston serves to seal the valve.
Hotrod Magazine did an article about an experimental magnetic valve actuated Ford Pinto Engine; this was 20 years ago but it only ran on a dyno under controlled conditions.
Posted by: Fred | 21 December 2006 at 02:24 PM
Can't see many downsides to this other than cost, but that should come down over time, especially if/when it catches on, and you have economy of scale. On the positive side, you have enhanced performance, fuel economy, and likely better engine longevity. Plus, no need to worry about bent valves from a broken timing belt/chain.
Posted by: Bob Bastard | 21 December 2006 at 02:26 PM
The >100lb-force is required of the spring to keep the valve from floating at high rpm due to the inertia of the valve that increases rapidly with increase in engine rpm.
Smaller DOHC valves have a lot less mass, hence less inertia that would allow higher engine rpm or weaker valve springs, but high-rpm engine will always need strong valve springs.
The situation is not different here because the mass of the valve itself would still be there. Now, we also have to worry about the additional reciprocating mass of the "armature and vane" in additional to the mass of the valve itself! I hope that they can make the armature and vane real light, thereby keeping the electrical current required for valve actuation within reasonable limit!
Posted by: Roger Pham | 21 December 2006 at 03:43 PM
Well, on a second thought, having electro-magnets on both ends can greatly reduce the force required from the springs. Force required to move the valve increases as the square of the engine rpm, and at typical cruise speed at~2000 engine rpm, relatively little force will be required. At higher engine rpm, the alternator can put out higher currents in order to power the electro-mechanical valves.
Posted by: Roger Pham | 21 December 2006 at 03:49 PM
I dreamed of this 30+ years ago when I was working on a 4 bit microprocessor design. I thought, "why don't people do this?"
Posted by: SJC | 21 December 2006 at 04:51 PM
In the past the power required to do camless like this would have been hard to do in a regular car electrical system. The power controllers were not efficient enough nearly doubling the power consumption. Now with hybrid and other power technologies this is within reach. This technology can allow the engine to switch from Otto to Atkinson cycle electronically and turn off any # of cylinders. Its gonna cost more then $400 for a half version for a long time though.
Posted by: hampden wireless | 21 December 2006 at 04:54 PM
Potential long-term impacts of changes in US vehicle fuel
efficiency standards by Roger H. Bezdek and Robert M. Wendling in 33 Energy Policy 407–419 (2005):
Estimates that camless valve actuation technology should produce an efficiency gain of 5%–10% at a cost of $280–$560 per engine.
Up to 20% seems to be a bit of a stretch
Posted by: Robert Schwartz | 21 December 2006 at 05:24 PM
Do you think it would be a good idea to use elecromagnetic rotary valves instead of poppet valves? That way you could adjust the valve timing over a wider range and a malfunction wouldn't ruin the engine. Also, there would be less distortion of the intake and exhaust air flow. I know this would mean more R and R costs; however, the improved air flow would most assuredly make the engine more efficient.
Posted by: Ladson | 21 December 2006 at 06:14 PM
I've been reading about this general concept for close to 30 years; the technology to implement it wasn't there until recently. It will be one of the single biggest steps in the on-going development of the IC engine. I take the 20% efficiency gain with a grain of salt, but even a solid 10-15% would be great. The other aspect of this is that it is the final step in decoupling all accessory drives from the engine. Recent developments in electrically driven water pumps, AC, power steering, (all developed for hybrids) means that the impetus to go mild hybrid across the board is very great. With the 42 volt electrics and batteries necessary for both the electric motor as well as all the accessories, and you have a blueprint for the future non-full hybrid standard car, one that could achieve 20% to 30% gains over the current conventional equivalent car.
Posted by: pauln | 21 December 2006 at 06:34 PM
plus when these engines get old, they won't have the timing belt time bomb problem.
with a 15 year old car worth $1k, it is hard to justify a $750 maintenance bill, so some people skip it and just get rid of the car when the timing belt eventually goes.
keeping old cars on the road longer reduces the lifetime toxic emissions per mile because most of the toxic emissions from a car are from the painting process.
Posted by: shaun mann | 21 December 2006 at 10:27 PM
Shouldn't we be trying to encourage people to scrap 15-year-old cars and get something new(er), more efficient and less polluting?
While I'm all for efficiency improvements, 15% is way too small. We need to aim for PHEV territory, starting at 50% and working towards 80%.
Posted by: Engineer-Poet | 21 December 2006 at 10:45 PM
I actually have sent link to this article to Mike couple of weeks ago, but no matter, thanks to Patrick and Mike for publication. According to number of comments, it is interesting one.
Big two-stroke marine engines universally use electrically-controlled hydraulically-operated exhaust valves (intake being actuated by piston movement opening cylinder wall intake ports). On low-RPM marine engine (60-120 RPM) hydraulics work well. Fine tuning of exhaust valves opening is one of the reasons of incredibly high thermal efficiency of such engines, the highest among all thermal machines used by mankind.
In a discussion took place couple of weeks ago, Rafael explained that Valeo electromagnetic valves have severe limitations. While not in operation, valves are kept by springs in intermediate half-open position. In order to begin operation, electromagnetic valvetrain should oscillate valves with increasing amplitude in order to reach lockable open/closed position. I am kind of puzzled how such mode of operation allows for start/stop engine operation and cylinder deactivation. Anyone have better idea how this stuff works?
Also, I am pretty sure that their estimations of 20% better efficiency are measured against fixed timing valvetrain. Compared to modern mechanical variable valve timing, efficiency gains should be smaller. Another limitation of electromagnetic valve technology is its inability to modulate valve lift. Valve lift is very important for intake port fuel injected engines: at part throttle operation it is necessary to maintain small valve opening to increase speed and pressure drop gradient of intake charge to promote explosive atomization and evaporation of fuel droplets. Direct injection gasoline engines do not have such requirements.
For about 10 years practically all engines have non-interfering design. You have to check specific engine for this. It means that piston head has recesses in form of poppet-valve face, and piston physically can not collide with valve even if valve is fully open in case of timing belt fracture. Repair shops are quite reluctant to mention this feature of modern engines, and force customers to expensive (especially on Japanese engines) unnecessary timing belt/chain replacement. Contrary to information they provide, timing belt usually lasts for 20 years, and timing chain, well, forever.
Posted by: Andrey | 22 December 2006 at 02:16 AM
BMW has been using a fully variable mechanical valvetrain (Variomatic) for the inlet valves of its engines for some time now. This allows them to keep the butterfly valve throttle open fully open except in certain very unusual circumstances. Average savings over the NEDC are 7-10%. Other purely mechanical designs exist.
Valeo's claim of 20% may apply to a particular point in the engine map but it is unlikely their electro-magnetic valvetrain is substantially better or cheaper than those developed by Lotus and FEV for research testbeds. Such systems exhibit high electric power demand, in part because unlike cam-based drives they do not recuperate energy as the valves close again.
Posted by: Rafael Seidl | 22 December 2006 at 04:22 AM
I believe part of Valeo's "up to 20%" claim takes into account cylinder deactivation.
BMW's mechanical Valvetronic setup is limited in response time and application (as BMW themselves have stated).
There are still Interference over-head cam engine designs. Look for the manufacturer's recommended timing belt maintenance schedule as that is a good indicator. If they list anywhere from 60,000 to 90,000 miles then it is likely to be interference design. More mileage and it is likely to be non-interference. Actual life of a timing belt will depend significantly on the severity of usage of the engine. Some people burn through a timing belt in less than 100,000 miles...others can get a timing belt to last 200,000 miles. I'd rather not take the chance and just change it close to the recommended schedule.
Posted by: Patrick | 22 December 2006 at 08:03 AM
Cam less IC engine designs have had most of the benefit taken up by variable valve timing and also cylinder deactivation.
Nice try but its no panacea, unfortunately.
Conversion to electric propulsion for the most part through PHEV technology, is the future for allowing all the world to have the lifestyle of the developed West. And that is what the undeveloped world is determined to get.
Only supercilious and ineffectual liberals will proclaim the need for the the "proletartiat masses" to walk, or ride 1800 mass transit technology, and get off the roads so their "betters" can have empty lanes for their speeding limos.
Just like "egalitarian" communist Russia had as a standard policy for the Party bosses.
Its also the only method that will cause the "global warming" phoney scares to be averted. A case where scaring the populace as a way to political power backfires on the anti-technology coacal cavites.
Posted by: Stan Peterson | 22 December 2006 at 04:14 PM
What sort of money would you put on the claim that global warming is phoney, Stan? Do you have the courage of your convictions?
Posted by: Engineer-Poet | 22 December 2006 at 08:20 PM
Well it's not exactly "new" technology, considering Formula 1 ditched camshafts years ago, albeit using pneumatic activation instead of electro magnetic. The real news here is the $400 cost. That's a LOT of money for a manufacturer to sink into an engine believe it or not, but it's cheap enough that it will get adoption at least in the high end cars first and hopefully continue to get cheaper over time.
As for the mention of BMW, that's still a conventional engine, conventional valvetrain, and in fact a conventional fixed camshaft. All BMW did was float the camshaft locator so it can move the camshaft up and down relative to the cylinder head instead of bolting it hard to the cylinder head like every other engine.
Lastly, on the topic of people spending $750 for a timing belt and water pump change on a $1000 car, don't laugh but I've known plenty of people who would buy a car for $500 then end up putting $2000 into it in maintenance over the following year. It happens!
Posted by: Sid Hoffman | 22 December 2006 at 09:38 PM
There are a lot of cars of 10-15 years origin which really worth spending of 2-3 grands to fix. But they cost more then 500$, check for example venerable Honda CRX, Acura Integra, or VW Corrado.
Posted by: Andrey | 23 December 2006 at 03:56 AM
I love all the skeptics around here. Why would this claim be so unreal with the following being a fact?
2005 BMW 330i w/ continuously variable timing = 18/25
2006 BMW 330i w/ continuously variable timing & variable lift on INTAKE VALVES ONLY = 21/29
Both had automatics and no type of cylinder deactivation. Granted, the '06 had a 6-speed auto (vs. 5), but it was also 100lbs heavier.
BMW's Valvetronic is admittedly not as responsive as the camless setup, and was only applied to the intake valves. According to my calculations, the combined fuel economy was improved by OVER 20% in this situation.
Posted by: Angelo | 23 December 2006 at 07:15 AM