Electrohydraulic Valve Actuation

[desmo]

FoMoCo have done a lot of development work on this concept. Right now the
principal downside for racing is weight. It may never be possible to make it weigh
less than a conventional cammed valvetrain. The obvious upside is the same
freedom in valve timing as allowed by a solenoid system. Either can be controlled
electronically. I think that some of the components in the illustrations could be
shared by more than one cylinder, perhaps an entire bank. This would get the
weight and complication within reason. Ford has made single cylinder prototypes
which are very promising.

[Dino IV]

Now you're doing your nick justice, desmo
An electrohydraulic version of desmodromical valve control

Can you tell something more about FoMoCo maybe?
Is this the same system as used on the Hunwick Haslam X-1 Superbike prototype perhaps?

Sharing most components and only using pressure lines would be the solution to the weight problems.
Pressure lines should be reinvented probably because of their expansion stretch. Maybe imbedded canals inside the head could do the job but sealing problems could cause immense problems. Is Ford the only one of the F1 teams right now? Wasn't there a rumour Toyota and Honda were testing with the same principles?

[desmo]

FoMoCo = Ford Motor Company

I think that the motorcycle you refer to had cams, but pneumatic valve closing like an F1 car.

I don't think sealing is as much of a problem as getting hydraulic actuators to cycle at anything like the speed required to run an engine at 18,000rpm.

This is still pretty blue sky stuff. Ford are working in conjunction with several universities. This suggests to me that as work conducted at universities is published, this technology is nowhere near ready to appear in F1 cars. If I understand the problems correctly, this technology like solenoid valve actuation is probably more likely to appear in road cars before it will be seen in F1. Renault might spring solenoid actuated valves in F1, but it would really surprise me.

[koenda]

Hmm... that's some interesting stuff you got there Desmo

but I wonder if the valves can be operated with enough speed to be able to reach the +18 krpm. I also wonder what the power required for this kind of valve-operating is. I can imagine that the oilpressure should be pretty high. The pump that has to generate this pressure, with enough massflow, could be very power-consuming.
The PSA concern already has a functional Diesel Engine with solenoid-valves and the rumours were that BMW also is working on an engine with solenoid-valves and Renault already has one on a test-rig. But these are rumours... so you know you don't have to trust them

[Gerard]

Welcome to 10-Tenths, koenda.

[Dino IV]

Hey koenda!!!
Welcome to 10-Tenths!

I figure if response of hydraulic systems can be as high as the frequencies seen in F1 valve actuation.
Slow response even caused problems with active suspension systems and those are operating at 10 times lower frequencies.

Does anyone know any details about the Hunwick Haslam bike?
The normal ones feature cams as usual bbut they are running one without. Either electrohydraulic or electromagnetic valve actuation.

What about the latter?
Response is superb compared to hydraulics and add-on weight should be lower as well. Anyone?

[koenda]

Hey Dino

I have looked and found some explanation of the Electromechanical Valve control. Apparently it's patented by FEV.
http://www.fev.com/03eng/02ed/e_ed_vt.html
(just for information)

[Dino IV]

Thanks, koenda! I described exactly the same system to red27 this weekend. I figured it out of the blue but it was quite logical to have fixed limits on the valve in the form of steel rings and just click it up and down between the electro-magnets to it's desired closed and open position.

We had a discussion after that if it would be an option in racing engines for instance. It's obvious this system has its limitations as the valve lift is fixed and cannot be changed. So when variations in valve lift are required, for example for torque and peak power optimization at mid and high revs, this system wouldn't be feasable.

However valve opening times can be adjusted simple by the ECU; so there's room to vary the fuel-air mix and valve overlap. Engine characteristics are highly adjustable that way. Drivers would be able to chose for more evenly spread torque instead of peak power in wet track conditions for instance or can run much more effective fuel economy if they want to compared to the current situation where just the mixture is altered but overlap remains the same.

How can this system be redesigned to allow adjustable valve lift as well? I was thinking about this: the upper magnet position is fixed as it defines the closed position of the valve. When the lower magnet can be moved up and down between the minimal required value (i.e. stationary) and the maximal lift allowable (i.e. at max revs) the system becomes fully adjustable. I was thinking of a coil between the magnets, forcing the lower magnet downwards and below the lower magnet a pneumaticly pressurized room as used today in F1 for valve closing. Adjusting the pressure moves the lower magnet up and down. Those moves are not as limited by response time as the lower magnet does not has to adapt itself every revolution but just through the alterations in the applied rev range, i.e. slowly lowering when revs go from 50 to 100%. Disadvantages are obvious, second system, added weight etc; but I couldn't think of something more feasible yet.

Response time is crucial for the valve itself though. FEV states this system currently can be run up to 6.500 rpm. Useless for racing engines it seems. But where are the limitations? The mass of the valve is one. It has to be strong enough to withstand hitting the magnets time after time. The stopping ring between the magnets adds weight and it has to be of material which reacts to the magnets. So preferrably it has to weigh 0 g and be as strong as a rock. The magnetic intensity has it's limits too. It has too be as strong as possible to increase response time, but the more heavy they'll have to be and the more power they require, the more energy it consumes. So till what degree can high revs be reached. The system promises virtually limitless control up to revs way beyond cams could reach but not yet. Material, construction and magnetic optimization can do the job towards ranges of 20.000 rpm I guess, but beyond? I dunno ...

[koenda]

Dino>

I was wandering about that too, because you want to influence the airspeed of the incoming air to have more influence on the airflow in the engine.
Maybe you can adjust the magnetic field of the magnets. But I don't know if the springs are balanced. (doesn't look like it, because it has a neutral position). If the springs aren't balanced, maybe it can function. But I don't know if the opening-time and responce time will be short enough

I believe more information can be found in "Auto en Motortechniek" but unfortunately I don't know which month...
It's about the diesel-engine of PSA with EAV and 42 Volts electric circuit with integrated starterengine in the fly-wheel. (don't know if this is the correct translation)

[koenda]

I have found a sae paper about the electromagnetic Valve actuator. It's an Aura system that is applied to a Kohler engine. it's number is 981908.

the electrohydraulic is described in 970248.
I'll read it this weekend, maybe monday I have something usefull to say

[Dino IV]

Next monday?

[koenda]

errrmm...

apparently i didn't have anything usefull to say...

[desmo]

Admirable candor there Koenda! Now about your tardiness...

[koenda]

Hey, wait a minute: I said maybe

But in the article i've read about the new BMW engine (316ti), they said the performance of electrohydraulic valve actuation varies with oil temperature.
That I didn't think of this before as with oil temperature the viscosity and density varies and of course the flow through the orifices and valves vary because of this...
then i would have had something usefull to say