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Valeo Research Program for Vehicle CO2 Reduction to Receive €61M in Funding from French Industrial Innovation Agency

5 March 2007

Camlessuk
Valeo’s camless Smart Valve Actuation technology. Click to enlarge.

The French Industrial Innovation Agency (Agence de l’Innovation Industrielle, AII) will provide €61 million (US$80 million) in funding to Valeo for its research program LOwCO2MOTION, which aims to improve vehicle engine efficiency and contribute to reducing CO2 emissions.

The program is focusing on the development of two primary technologies: camless systems and a next-generation mild hybrid with ultracapacitors for energy storage. The two systems together could provide up to a 30% reduction in fuel consumption, according to Valeo.

In the camless system, the camshaft in engines is replaced by electromagnetic actuators that operate each valve independently. By controlling residual gases, minimizing pumping losses and deactivating cylinders and valves, this technology reduces fuel consumption and pollutant emissions by 20% for gasoline engines, according to Valeo. It also provides enhanced performance and driving comfort due to an increase in low-end engine torque. (Earlier post.) A version for diesel engines will also be developed.

The next-generation mild hybrid work is based on Valeo’s StARS+X technology. In addition to the Start-Stop function which cuts off the engine when the vehicle is at a standstill (StARS, earlier post), this system features a regenerative braking function, where energy generated during braking is recovered.

The program includes the development of a new high-efficiency, high-power alternator technology as well as ultracapacitors, enabling a 10 to 15% reduction in fuel consumption. These innovations will be enabled by new mechatronic technologies which are also part of the program.

The LOwCO2MOTION program represents a total investment of €212 million (US$278 million) over a four-year period. The AII funding is subject to the approval of the European Commission.

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March 5, 2007 in Engines, Fuel Efficiency, Hybrids, Vehicle Systems | Permalink | Comments (14) | TrackBack (0)

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Before anyone else even has to say anything I'm sure they mean 20% reduction in fuel consumption versus an engine with static camshaft valve timing and valve lift.

LOwCO2MOTION sounds like a really ridiculous name for such a serious and expensive project. I initially misread it as LOwCOwMOTION. Then again, this is France.

Note that Valeo's system is functionally very similar to those developed by Lotus and FEV several years ago. Those proved too expensive for anything but research engines, mostly because a regular 12V grid cannot supply sufficient juice to power a purely electromagnetic valve train at high RPM.

Like many other automotive suppliers, Valeo would presumably like manufacturers to switch to a higher voltage, e.g. the 42V systems that were proposed but never got off the ground. Since ohmic losses are proportional to the square of the current, tripling the voltage permits almost 10x the power flow using the same cables. This greatly facilitates mild hybridization (cp. Saturn Green Line), electric power steering, electric wedge brakes, electric water pumps, electric rear window defroster in addition to a fully variable electromagnetic valve train, all at the same time. Even electric A/C is possible.

The snag is an increased risk of short circuits and leakage currents, especially if dirt builds up near contacts. These problems are solvable, albeit at increased cost. A DC-DC bridge to the old 12V grid can be added so lights and small electric motors can remain unaffected. Perhaps the EU's new target of 130 g/km fleet average CO2 emissions will prompt ACEA members to agree on a firm date for cutting over to higher voltages. MY 2012, anyone?

I would think diesels would be a prime cantidate as they tend to redline at about 4k RPM.

Ihave read Mercede has palns for a camless engine in a few 2010 models.

These estimated mileage improvements are absurd. Theree are benefits but the gains can only be relative to a single cam engine without variable valve timing. Most of the benefit from a camless engine is already been achieved with that technology, especially if it is variable for both intake and output valving. Many advanced engine familaies now have that VVT technology so this is not a "breakthrough".

You can't remove the throttle plate in any type of variable valve timing or lift engine other than BMW's valvetronic so there are still gains to be made.

Additionally, other than Valvetronic, variable valve lift tends to chose between two separate but distinct cam profiles while this would allow an infinite number of cam profiles to be emulated.

That IS a breakthrough.

BTW - power to operate the electromagnetics probably is less than the power sapped away from two camshafts, two cam gears, hydraulic variable valve timing valves/solenoids/motors, and the larger timing chain/belt when operating at high rpm.

This seems like a perfect fit for a horizontally opposed twin 500- 700cc genset. It would lighten the engine to allow for more batteries and take up less space.

Doug -

diesels can be leaned down very far in part load so there's no need to adjust the density of the fresh charge. Fixed valve lift and timing work well enough. You'd be better off spending the premium on an aluminum crankcase, variable geometry turbo, fancy piezo injectors and/or exhaust gas aftertreatment devices (especially for the US market).

Patrick -

a dual camshaft mechanical valve train on a gasoline inline 4 will eat ~1.6hp at rated speed. The energy stored in the springs while they are open is recuperated as they close, so the engine only needs to overcome the friction between the timing belt and its guides plus that between the cams and the tappets plus that in the bearings. Many modern designs feature roller-finger-followers to sharply reduce total valve train friction in part load.

EMVTs are based on valves that are half-open at rest, witness the two counter-acting springs. Since the crank train can end up in an arbitrary position after the ignition is cut, the valves may actually be touching the crowns of one or more pistons at rest.

Therefore, a reliable procedure for starting the engine while avoiding renewed contact between the valves and piston crowns is critical. You could use a special starter motor that can slowly turn the crankshaft forwards or backwards (as required) until all of the pistons are far enough removed from the valves. These are then excited into oscillation and then caught in the closed position. Catching a valve requires a brief pulse of high power, while holding it in one of the extreme positions requires only low power. For obvious reasons, valve actuation timing must be synchronized electronically with the crankshaft angle, with an accuracy at least as good as that of a timing belt or chain.

The mechanical energy stored in the springs of a valve is recuperated as the valve is actuated in either direction. There is little friction in the system. However, the valve also needs to be either caught or held in position by applying an electromagnetic force at virtually all times, and the electrical energy is not recuperated. The power drawn for this is significantly greater than that needed to overcome mechanical friction of a camshaft, especially if the springs are very stiff. The losses in the alternator, battery and electrical grid far exceed those of a timing belt or chain.

The upside of an EMVT is its full and instantaneous variability, combined with rapid transitions between the open and closed positions. This reduces gas exchange losses at high loads. Another feature is that there is no cost penalty for V or flat engine topologies, relative to inline arrangements. Cylinder head geometry is simplified.

The downside is that it is difficult to achieve anything but full lift with high fidelity. Releasing and immediately catching a valve might be possible but intermediate valve lifts are not. Instead, the time a valve remains open is used to control how much fresh charge or EGR is admitted, with implications for the gas dynamics in the respective manifold. On the intake side, this amounts to running either a Miller or an Atkinson cycle in part load rather than throttling the gas flow.

Since the valve-spring system has a certain natural frequency, there is a minimum time interval during which the valve is open if it is allowed to oscillate without catching in the open position. Note that the anchor plate is not itself a permanent magnet, so the coils cannot generate repulsive forces. The upshot is that significant part load portions of the engine map may still require the use of the butterfly valve in the intake manifold. This is not the case with mechanical fully variable lift systems.

Rafael,

The energy to open the valve will be used to close the valve but it will not go back into the camshaft. That energy is spent and must be expended again to re-open the valve. Otherwise there would be little value in making a valvetrain light weight...one could simply use stiffer springs to handle high rpm and save costs versus trying to employ exotic alloys that are harder to work with.

Patrick -

at very high RPM, getting a valve in a conventional valve train to close gain does mean accelerating it. The energy for that does indeed come from the spring. However, it's the cam that slows the valve back down, during which time the inertial forces do in fact push the camshaft. The work done is of course less than the potential energy that was stored in the spring due to friction but it doesn't just magically disappear.

The reason valves and valve springs of gasoline engines for sports and race cars are built as light as possible is to permit the engine to rev higher and therefore, to achieve higher rated power. There`s a trade-off with valve length, which is what you want for engine ports with low curvature and therefore, flow resistance.

At even higher RPM, the cam will turn away faster than the valve stem can possibly accelerate back to the closed position, causing momentary loss of contact. The elastic collision that occurs when hard contact is re-established damages the surface of the cam and valve.

Also, the valve spring might break, one reason why race cars almost always have two springs per valve to prevent catastrophic engine failure. Btw, those springs are very stiff indeed, because when your engine produces 500+ hp you really don't much care if valve train friction eats up 3 or 5 of them.

Raf,

Go crank a cam by hand and tell me just how much energy you feel going back into the cam from the springs versus what is lost to friction. There is a reason why race cars and exotics use hollow camshafts.

If you relieve the valvetrain of mass (rocker/lifter arms) you don't need as stiff a spring, nor do you have as much inertia to overcome. Each of those components in the valvetrain will add another point for friction and the mass of the components determines the friction at the interface between components. Very few engines have direct valve actuation via the cams (many DOHCs still use rocker arms...especially if they have a variable valve lift component).

Patrick -

I think were talking past one another. In a conventional camshaft serving at least four cylinders, energy recuperated when one valve closes is immediately used to open that of another another. The timing belt/chain is largely unaffected by this energy bouncing back and forth along the length of the camshaft. Banks with fewer than three cylinders don't do as good a job of recuperation, which leads to greater torsional vibrations. If you crank a camshaft on a V6 by hand, you will feel greater variation in the resistance as a function of crank angle than if you do the same on an I4.

Hollow camshafts are used to distribute pressurized oil to the contact surfaces and bearings. Modern ones tend to be built rather than forged and then hollowed out, because that makes them cheaper, lighter and usually reduces the polar moment of inertia a little bit as well.

I wonder if the spring configuration for the valves is really as depicted in the accompanying image. It's a very sub-optimal arrangement. The restoring force that the electromagnets must resist is proportional to displacement from the neutral position, and is maximal at the full open and closed positions. As a result, a large holding current is required to hold the valve open or closed, draining power.

A better arrangement mimics the behavior of a compound archery bow. The pull is substantially reduced a full draw. In the electrically activated valves, that would mean less holding current needed, and less total mass in the holding plate and magnet assembly.

Any comment, Rafael? Or has this thread gone stale?

Rafael
A sustantial part of the energy used to lift the valve and to mantain it in position (1/2 L*i2) could be recuperated when you release it ( via the parallel diode in the switch transistor, the coil itself and stored in a capacitor as near as possible to the coil ,in parallel with the battery) and used in the next transition.This is the most common electromagnetic energy recovery system and I suppose Valeo is using it in both upper and lower electromagnets.
In conventional cams the shape is optimized for timing performance and not for energy recovery, thoughg some energy is recovered.

Very large voice coil actuators like those in large speakers (woofers) but smaller than those used in ancient computer disk drives could be used to move automobile valves at any speed. Automatic pulse width modulation would reduce the power required to a minimum level with the chance of some energy recovery. Innovative construction techniques could allow the voice coils to operate at very high currents with the resulting high power but also high temperatures.

Relatively weak springs or bellows could keep the valves in a closed position when power is off and the engine is not running, and they could also center the valve so that it needed no guides. Multiple spring wire leads can connect the voice coil to the fixed terminals. If springs don't break often neither do well designed spring wires. One of the free piston stirling generator companies has developed a flexure that could also support the valve stem and voice coil.

A capacitor-inductor computer controlled tuned circuit could reduce the wasted valve actuation energy to a minimum if that became important. It would probably save more energy to have electric power steering and power brakes and water pumps.

The windings in alternators for cars could be directly connected to a transformer that would supply any needed voltage for operating the valves efficiently. A small bank of nickel-cadmium batteries could be used for starting the valves, not the car. EFFPOWER could make a compact version of their high voltage lead battery for the same purpose.

It would be interesting to actually know the horse-power that is consumed in the valve train of modern engines. The minimum power could be measured by taking out all of the pistons and piston rods and turning the engine at different speeds with no other accesories connected.

In an electric hybrid car, the regular version of the EFFPOWER battery would be better than any Ultra-Capacitor for equal useable energy capacity and probably cheaper for useable actual equal peak power capacity.

It is well known that diesel engines have the highest efficiency, and that diesel is cheaper to produce than high octane gasoline. The production of diesel fuel probably also releases less carbon-dioxide than does that of gasoline, and in the future that carbon-dioxide should be considered with the carbon-dioxide that is actually released during the operation of the vehicle. Diesel hydraulic hybrids can probably out perform any proposed vehicle, including fuel-cell hybrids, for efficiency, and they cost less to build than any hybrid in production quantities. No fuel cell hybrid will ever produce less carbon than a diesel unless the hydrogen is produced by nuclear power, and in that case or any other case that produces hydrogen with electricity, the electricity can be used with nearly twice the efficiency in an electric or plug-in-hybrid car.

With the consideration that diesel is more efficient than gasoline in most cases, all cars should be produced with diesel engines and all pollution control efforts and research should be shifted from gasoline to diesel or electric cars. The end destination for automobile development has the plug-in-hybrid car in its path. Efficient diesel-hydraulic-hybrids can now be built, and the NOAX diesel hydraulic pump is more efficient than any other diesel-engine-pump combination and produces fewer carbon and non-carbon emissions than any other diesel except for microturbines. The fact, that the NOAX diesel pump can be operated down to zero speed with the vehicle still moving, gives it much of its high efficiency that all of the inovative valve control cannot do for a gasoline engine. Very high speed operation of the NOAX pump, that would cause piston rods and bearings to fail, gives the ability to get short periods of very high power from a smaller engine.

Hydraulic systems can be tuned to high efficiencies at low cost by designing low friction pipe, valves, passageways and motors. Air pressure tanks can store energy at less cost and complication than Ultra-Capacitors and have equal or better cycle life with no need for complex electronics. Large and small pressure accumulator tanks can be fit into any available area and connected with a simple tube. More complicated sytems could even heat the air in some tanks with exhaust heat for higher performance. NOAX has also invented fluid pressure energy transformers that could increase efficiency.

I don't get paid by NOAX; I don't even like the company because they don't produce the things they develop or set up a company that does produce them, and then they just sit around hoping that someone will buy property rights or new research. Caterpillar supported the research on the NOAX engine with the excuse that it might reduce the energy needed to run the hydraulic devices on its machines, and it would have, but it would have made their present machines look bad and competed with some of the other diesel engines they also produce, so they seem not to be supporting it.

HG..

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