36 replies to this topic

[desmo]

The subject comes up from time to time, so here's an illustration of the concept from Renault.

[BRG]

desmo

Interesting…a few things come to mind. It seems to take up a lot of room vertically which wouldn’t be popular in F1, but I suppose it could be modified to get around that.

How much power would the electrical system require? With big valve timing overlaps, aren’t the valves at least partly opening against compression which would call for more effort by the valve actuation system?

Valve closing does not require any assistance as we know from the desmodromic valve Mercedes engines of the 1950s. These relied on engine compression to close the valves - I believe that the hairsprings that Mercedes originally fitted were found to break every time the engine ran so they concluded it didn’t need them. It took a good spin to get the motor started, but so do modern F1 motors.

A big advantage of this system could be that with a full computer management system, completely adjustable and programmable variable valve timing is possible. As anyone who has driven a VVT Honda or Toyota will know, this can provide a docile engine at low revs and high power at high revs. This would give wider rev bands, more driveable engines and reduce the danger of stalling at starts and pit-stops - all big pluses in F1.

So, who is going to use it first???


------------------
BRG

"all the time, maximum attack"

[Ray Bell]

As soon as the valve opens it breaks the seal on that compression, so any additional current-drain would be very short-lived.
Because of the rev range, quickness of opening would probably require a hefty charge anyway.

[Art]

The clearance between electro magnets would only be slightly more than total velve lift. Which would make it very compact. And on the W196 cams they had two cam lobes per valve and a split rocker arm. The last few thousands of an inch ov valve closing was done by compression.

Art NX3L

[CVAndrw]

Hah! That's exactly what I was suggesting on the "Eliminating Engine Parts" thread. I don't think there's anything in Section 5 of the Technical Regs that specifically bans computer controlled variable valve timing. I'm wondering though if as many as fifty little electromagnets per cylinder head might well be as weighty as two simple steel camshafts and their gear or belt drives?

Perhaps another drawback might be a current F1 engine's extremely "dirty" electrical environment. I remember a few years ago Benetton experimenting with a fiber optic wiring loom to specifically get around this problem- did anything ever come of this?

[mojo jojo]

Fuel injector operate on the same principle.

The problem as I see it is speed. At, say, 15,000 rpm the engine spins around once in 0.004 seconds, or half a rev in 0.002 seconds. The valve would have to be able to open and close in about this time. Really, it would have to operate even quicker than that, to garauntee any kind of precision timing. Anyway, lets say open in 1/4 cycle, close in 1/4 cycle, 1/4 cycle = 0.001 seconds. If the valve has to open .5 cm, this means an acceleration of 10,000 m/s^2. If the valve and magnets weighed 50g, a force of 500N would be required. That seems like quite a bit for a small solenoid. I don't know though, I'm not an EE.

[desmo]

mojo,welcome to the forum. I think you've put your finger on two of the major issues making this type of actuation unworkable at this time for F1 use. The concept works in prototype applications up to about 6K rpm. It may well appear in road cars before it appears in F1.

[Art]

Mojo is correct this may never be used in F1 but it would sure cut the cost of production engines. Huge profits for the Manufacturers.

Art NX3L

[tak]

Several years ago I saw an article about Lotus Engineering experimenting with a solenoid actuated valve system. As in the diagram above, it had a pair of electromagnets, so during actuation, one pushes, one pulls. If memory serves, they could only turn 5000 RPM--the mass of the valve was simply too much to move faster.

[desmo]

Even if someone made it work on an F1 engine, the FIA would ban it the minute it showed any real potential.

[Yelnats]

BRG. About the Mercedes Desmodromdic Valve gear. Desmodromdic valves have the enviable feature of not requireing any valve springs to operate, true. But this is because they have an additional set of rocker arms operating from a secondary cam lobe(or if your very clever, from the the same lobe) which forces the valve closed positivly. So yes valve springs are not required. Incidently atmospheric closing of valves was abandoned pre-WW1 because of RPM limitations and the wasted charge leaking around the valve being forced closed.

Re Solenoid operated valves; There is at least on vehicle running around the USA (a Ford Ranger!) that is testing Electromagnetic Valve actuation, in Texas I recall. It suffers from high noise levels because of the valves hammering open and closed because without benifit of the the ramping action of the cam profile. It also is limited to low RPM and runs on Propane, a long way from a F1 car indeed.

The firm (can't recall it at the moment) is working on providing positive control of the valve opening and closing cycle instead of just flinging it open open and closed violently as this is a big problen at high RPM.

[desmo]

Here are a couple of illustrations that should help:





Looks simple enough until you have to start changing shims to adjust the valve lash! The small clothespin springs (#5 in the top image) on the closing rockers are not used on the race version of this (Ducati) engine.

P.S. There are rumors afloat that the new Honda engine in the BAR has desmo valve actuation.



[This message has been edited by desmo (edited 03-02-2000).]

[Yelnats]

Desmo, Super animation of Desmo Valve systems, Desmo, you've lived up to you name here!

Not to quibble but it's impossible to define a secondary rocker/cam from your animation. I called the closing rocker a secondary because it supplements the traditional opening rocker but this is all semantics and the principle remains unchanged.

[desmo]

Yelnats, of course you are right. Thank you for the clarification.

[BRG]

Of course, we are all assuming that you use poppet valves with the electro-magnetic actuation system. Another answer might be to use sleeve, flap or rotary valves - would any of these get around the RPM limitations that seem to be the problem with applying this to competition motors?

------------------
BRG

"all the time, maximum attack"

[desmo]

BRG,
Sleeve valves are complicated and involve a lot of recipricating mass. The motion is complex, not a simple rotary motion. They had been supplanted by poppet valves in aero engines by WWII.

Flap valves, like reed valves in a 2 stroke, Are restrictive and don't allow for overlap limiting volumetric efficiency.

Rotary valves in a four stroke engine have so many potential problems, I don't know where to begin.

These all have sealing limitations as well. I'm afraid we're most likely stuck with poppets for the four-stroke piston engine.

[Ray Bell]

Another reason we're stuck with poppets is that they alone don't hinder combustion chamber shape.
On the benefits of electro-magnetic valve operation for road cars - not only profits in the manufacture, but there'll be other benefits down the road. For the makers. Spare parts will go through the roof!

[desmo]

Art,
Actually I believe poppets do hinder combustion chamber shape. At the extremely oversquare bore to stroke ratios and high valve lifts necessary to move enough air through a modern F1 engine, the valve reliefs in the top of the piston define most of the combustion chamber area near TDC. This is far from ideal. To see a relatively uncomprimised combustion chamber, look at the head of a racing two-stroke. Any four-stroke designer would love to be able to create a chamber such as that.



[This message has been edited by desmo (edited 03-05-2000).]

[Yelnats]

If I recall my two stroke facts correctly I belive they run a much lower compression ration than a four stroke. Wouldn't this give a more ideally domed shape to the combustion chamber? It's been 30 years since I looked at two stroke designs so things could be very different today.

[desmo]

Calculating compression ratio in 2-strokes is not as simple as comparing cylinder volumes at the point the exhaust port is covered with the volume at TDC. True c.r. dynamically increases with rpm as the rising piston will beat some of the air column in the cylinder to the exhaust port, building pressure before the port is covered. This is referred to as "trapping efficiency".

With clever exhaust tuning using expansion chambers, it is possible to exceed 100% volumetric efficiency within a limited rev range!

Published c.r.s for 2-strokes seem to mostly run between 8:1 and 11:1, similar to those of 4-strokes.

[Yelnats]

Obviously they have done a lot of work with expansion chambers since I visited the 2stroke topic 30 years ago (witness the power of my sons 125cc moto-cross bike).

F1 has a lot to benifit from 2 stroke techniques of resonance charging/extraction. With improvments in onboard computers and stepper motors, managagment of resonance intake/exhaust columns on multi-cylinder designs are now becoming possible

[Billy Gunn]

Hey boys this one's jus gonna run an run!
Good to see you've got so many comments to make about this subject. I've read them all with great interest, glad that you raised it Desmo!
Personnally I think that ElectroMechanical actuation of the valves will be the next big breakthro for the reciprocating engine. Lets take a look at the pluses and minuses.

Points for E/M valve actuation:-
1. Infinitely variable timing of open and close point, valve lift, and duration.
2. Camshaft and related drive gear redundant.
3. Throttles and related actuation system redundant. The engine can now be throttled by way of the programmed valve duration and lift.
4. Freedom of design for valve shape.

Points against E/M valve actuation:-
1. eeeeeeeeerrrrrrrrrrrrrrmmmmmmmmmhhhhhhh!

Well there is one, and it's a rather major point. It's the recovered energy from the currently used spring medium system. According to a rather whiz engine simulation software program a V10 40 valve engine running at 18,000 rpm will absorb 120hp in its valve drive train, but it will also release 100hp by virtue of the recovered energy from the spring. This is the crux of the issue and the answer to this will also redeem the absurdly tall actuation image at the top of the page (sorry Desmo, no fault of yours - I blame Renault for misleading everybody into thinking its that bad!!!).

Hands up all the Non PC smokers out there! (No I don't mean those of you who can only type so slow the keyboard will never have a spontaeneous combustion problem!!)you may have the answer in your pocket - a piezo electric crystal (cigarette lighter). This wonderful device can change a mechanical force into an electric current and vice versa, and it's stackable so you can determine the amount of movement you want, and its very, very small.
I have it on good authority that there are a couple of companies researching E/M actuation in the F1 world, maybe Renault as they have suggested a road car could be in production in the next year or so with a camless engine.
The biggest pro for all this is highlighted by one of you who mentioned current valve design not being optimal for the chamber - just think what shapes you want with this system!
Just some other points that I noted reading your comments - Yelnats: 2 stroke style exhaust tuning is out because of the ban on variable geometry exhaust systems, although there's nothing to stop you using Standing wave Pipes (Holm Hertz Resonators!). Personally I was surprised that Yamaha did not try something similar to their EXUP bike system (but then again maybe they did and it wasn't worth it) Some one else wrote (and I apologise for not remembering their name) who said sleeve valves on aero engines died out during WWII - wrong!!! The highest powered, highest reving, most compact engine during WWII was the H24 Napier Sabre fitted to the Hawker Siddeley Typhoon MkI & II, with Burt-McCullom sleeve valves, this revved to 4,000+ and in it's final form produced over 3,000 hp. A sound to behold when on take off (so I'm told).

Nomatterhowhardyoupolishaturdwontshine

Billy G

[desmo]

BG,

Good reading there. The potential upside of E/M valve actuation is so tantalizing that the concept is bound to be the subject of intensive further development.

BG, I have never seen a piezo electric motor. Can you steer me to an application that uses the electrical to mechanical enrgy direction?

I don't see how E/M-VA will alleviate the problem of the combustion chamber shapes in current F1 engines. As long as the bores are pushing 100mm and the valve lifts are approaching 20mm(!), and I don't see how E/M-VA will help here, you are stuck with these horribly compromised combustion chamber shapes.

A couple of symptoms of this problem are limited compression ratios, around 13:1 being about the maximum possible with the current designs, although this downside is mitigated by the current fuel restrictions. I'm told that F1 engines run fine on roadside pump gas with the ignition advance fiddled a couple of degrees. The fact that F1 engines are likely running 50 or more degrees of advance speaks volumes about the tortured flame path and high surface to area ratios designers are forced to live with to make these engines breathe at 18K+ rpm.




[This message has been edited by desmo (edited 03-08-2000).]

[BRG]

Billy Gunn

Perhaps I am misunderstanding your comment about recovered energy from valve springs. Obviously valve springs absorb power as they are compressed, and take more and more power as rev limits increase (needing harder springs).

But you seem to be implying that when they decompress again, the energy is returned to the engine? Surely it is simply lost, presumably as heat? Can you clarify please?


------------------
BRG

"all the time, maximum attack"

[Ursus]

BRG, as I understand it: when the valve closes it follows and pushes against the profile of the camshaft on the 'closing side'. When it does this it is actually helping the shaft to rotate.

------------------
Ursus
Trust me, send money.

[Billy Gunn]

Desmo an BRG,+ the late starting, but coming up on the inside rails there with the correct answer: Ursus

Firstly to Desmo: I can tell you that when electronic digital fuel injection systems were first being developed, one of the major stumbling blocks was that Bosch held the Patent on the solenoid operated fuel injector which they bought from Bendix (the other major Patent was held by Lucas Electrical who had the rights to Digital mapping of fuel and ignition, this was bought from Brico Engineering). In an effort to get around the Bosch patent rights a Piezo crystal operated injector was developed by Ferranti - this operated by hitting a Piezo crystal with a PWM electric current to suit the fuel requirement. It was succesful as far as in injector went, but I believe the control system was its weak point. Other than this application, I know of other, how shall I put it? applications which were related to Ferranti's main business sphere at that time, namely, armaments, and aerospace, but which must remain closed to this open forum. Lets just say that it is possible to hit a crystal stack with a release of electrical energy (similar to a discharge ignition) which can result in the stack moving a considerable distance. By picking off levels of the stack it is possible to vary the distance moved. This is the inverse of the cigar lighter which uses the mechanical force striking a single crystal to create a voltage.

Secondly to BRG (British Racing Green perchance? When you compress a spring, be it a metal wire wound coil, or a piston against a fixed volume of air, the compressing force is transformed to kinetic (stored) energy. Remember energy cannot be destroyed, only converted to another form be it heat or otherwise. Some of the compression force is, as you correctly point out, transformed to heat (the adiabatic component in an air spring) but this is a small proportion of the total. When the cam passes its peak lift point the valve starts to move back towards its seating, what causes the valve to close ? - the cam does not 'pull' it (unless its a Desmo!!!!), the cylinder it serves has no closing mechanism. The only way in which the valve can close is because all the work (well almost all!) done in compressing the spring medium and converted into kinetic energy is now re-released to return the spring to its state of equilibrium - result - the valve moves, and the spring tries to turn the camshaft into the bargin - this feeds energy back into the motor. That's why when an engine hits valve float (the condition where the inertia forces of the valve overtake the stored energy within the spring with the result that the valve cannot follow the cam form after peak lift) power loss is greater than can be accounted for purely by lost valve motion control.

Hope this clarifies those 2 points - call me again if you have further questions/comments.

Gotta go to bed now - else I'll be late for my shift at the Sewerage works!

Yakeepascratchin-butitjustkeepsitchin

Billy G

[This message has been edited by Billy Gunn (edited 03-09-2000).]

[This message has been edited by Billy Gunn (edited 03-09-2000).]

[BRG]

Billy Gunn

I understand the basic physics - what goes in, must come out, as it were - but I am having trouble with the concept that the kinetic energy of a compressed valve spring is released back through the camshaft. Now this may just be due to my ignorance! - I am not an engineer! In your original post you suggested that :-

a V10 40 valve engine running at 18,000 rpm will absorb 120hp in its valve drive train, but it will also release 100hp by virtue of the recovered energy from the spring

OK, I suppose that if the camdrive (belt?) can turn valve gear that consumes 120hp, it can also cope with recovered energy of 100hp, indeed the two cancel out except for 20hp, so that isn’t a problem

But to my mind normal valve and camshaft design is hardly conducive to power transference and must be highly inefficient. The design is intended entirely for providing lift for the valve and controlling when it closes again , in order to get the right opening and overlap. If it was designed to transmit power back, it would call for a much more positive system using for example gears. In any case, cylinder compression plays a big part in closing valves. Early engines used flap inlet valves that were opened and closed solely by vacuum or compression. Not very efficient, but it worked.

I still can’t help thinking that most of that energy is "lost" as heat, rather than recycled. If your figure of 83% recovery of energy is right, then it is unlikely that any other system would be more efficient, so why would anyone be looking for one? Yet apparently they are….

And yes it is indeed British Racing Green



------------------
BRG

"all the time, maximum attack"

[Billy Gunn]

Hi BRG (are you code #25[Conifer Green] or code #75?)

OK, I think I see your (my) problem!
The idea that the cam drive transfers 100 hp back to the crank each time a valve closes is of course not the case. The energy lives in a balanced environment (sounds kinda groovy!), that is, at any snapshot in time, starting to open a number of valves, close a number of valves, not do anything at all to a number of valves - it is this environment which demands energy, and this environment too which energy is released to (from the compressed springs kinetic energy). The overall picture is simply energy consumed (this is the wrong word here as energy can not be destroyed only converted)= all work done.
Energy Input = Energy converted
= Kinetic energy + work done + friction

From this equation we see and understand that work done is the opening of the valve, and the friction element is convertion of energy to heat. The Kinetic energy is 'banked energy' which can be recovered later in the phase cycle. Therefore the input from the crankshaft for the next phase cycle is only equal to the work done + friction losses (which is around 17%-18%).

May I try another way to convince you that the 120HP does not turn to heat? - right, 120 HP = 89.485Kw OK?
The engine generates, say 750HP at the gearbox input shaft, a Morse test on the engine would reveal a frictional power of let's say 250HP. So the engine really produces 1000HP but has 250HP parasitic losses.
Empirical data shows that 80% of heat is lost to the exhaust on a naturally aspirated engine (go check my posting on the question of "where the air go?") so the engine produces a total of 1000HP, which is 745.7Kw - we know that the coolant system (both oil and water radiators) disperse somewhere between 13%-15% of the total heat, so the heat generated in the cam box must either go into the coolant (water and oil) or be lost as radiated heat. So we can now write a heat balance equation which shows that the camboxes 89.485Kw must almost totally be absorbed by the coolant system (see later allowance for radiated heat). As shown before the coolant system heat capacity has a limit of 745.7*.15=111.855Kw ( the 0.15 represents the worst case of 15% heat to coolant). So of the 111.855Kw coolant capacity 80Kw (I've allowed >10% radiated heat loss, far too much in reality)or nearly 70% is from the valve gear alone!

You are correct when you say that if the mechanical system is so efficient how can it ever be replaced. The point is not lost on the use of Piezo crystals as these devices, as explained are 2 way streets, hit it and it produces electric current, apply electric current and it moves. The energy cycle can be recovered from these crystals but within a shorter time phase than the mechanical systems. This will involve - move the valve from rest (energy input), - bring the valve to rest (energy recovery). And then do this twice per valve cycle. The advantages to be gained are too great to be missed, even to the extent that EMVA doesn't match the efficiency of a pure mech. system.

By the way, F1 engines rely entirely upon gear driven cams, the last engine with chain driven cams was the Cosworth JD of '97 - '98 (Team Stewart). You only had to see a plume of blue/white smoke to know where they were on the track! I think they were sponsored by a stunt air display team !!!!!!!they were definitely after the prize for most blow ups ever at Silverstone in '97 - I hear they lost 8 engines in 3 days, one engine blew in the garage straight after being changed for another one. Glad I don't have a Fix Or Repair Daily (FORD to our English Cousins)!

Hangyaganzyontneckiesneck!

Billy G

[mojo jojo]

I'm not usually one to nitpick, but...

the work done in compressing a spring is stored as potential energy. Potential enrgy is released as the spring returns to its original uncompressed length. Note this does not necessarily mean it is converted into kinetic energy. If you have a spring on the table and compress it with your hand, then bring your hand back to its original position, your hand doesn't shoot to the ceiling - you do work on the spring to compress it storing energy, then the spring does an equal ammount of work on your hand as you relase the force returning to an equlibrium position. Kinetic energy has to do with motion - the spring is moving, but not because it has kinetic energy.

Also, piezo-electric crystals distort under an applied voltage due to a deformation of the atomic crystal-lattice structure. Ultrasonic transducers create sound waves by applying a rapidly varying AC voltage (kHz/MHz+ range) to a piezo-electric crystal. To open and hold open a valve, a DC vlotage would have to be applied and held. As the voltage is applied, the atomic lattice distorts, storing energy. Once the voltage is released, the lattice returns to its original shape. While a p-e crystal does produce a current when distorted by an external load, that isn't quite what would be happening here. The voltage is applied, the valve opens, the voltage is released, the valve closes. There is no energy recovery in that sense. (sort of like the spring example above). The only energy needed to be supplied from the engine would be the electrical energy applied to the p-e crystal (if produced by an engine driven alternator). This electrical energy could not be recovered.

[This message has been edited by mojo jojo (edited 03-10-2000).]

[BRG]

Well, thanks for trying BG but I fear I am now blinded by science!!!

Obviously there is a lot of energy going into opening the valves and it has to go somewhere (I know enough about the laws of physics to understand that), so I must bow to your greater knowledge on this. But I take your point (and even follow it) about the amount of heat generated, which does clearly seem to show that the energy in the valve gear isn’t exiting by that route.

Clearly my career as a F1 engine designer is on hold again…..

PS As to colour codes, I don’t think we use that system in Britain. "Proper" British Racing Green is the shade that Mr Napier first used on his car back in the very early days of racing at Brooklands. It (sadly) isn’t the colour that the new Jaguars are using - that’s much to light a shade. The last F1 appearance for proper BRG was in the last days of Lotus, when some of the livery used it.


------------------
BRG

"all the time, maximum attack"

[Billy Gunn]

Hiya Mojo Jojo! and BRG.

BRG: Keep thinkin' about it - I'm sure you have the ability to understand what I'm trying to say. By the way, code #25 was the BRG color for Triumph TR's, #75 was the BRG paint code for 1975 Triumph Spitfires! Great British Sportscars that I have owned.


Mojo Jojo: I too don't wish to be nit-picky but according to dictionary definitions:

Potential (adjective) Possible; Latent; That which may be manifested !

Kinetic (adjective) Causing motion; Applied force actually exerted !

Now unfortunately I don't have the benefit of a University education but to me the difference between these two is a question of 'future indicative', versus 'current indicative'. So I have to agree that stored energy IS potential energy because it is future tense, but does the inclusion of the word 'stored' modify the literal tense of Kinetic???
I do appreciate your deep knowledge of the workings of Piezo crystals though - may I suggest that the electrical energy may be recovered by putting the stacks in a back to back fashion? A kinda push-pull, pull-push scenario, where their actions are mutually reversed through the cycle.

And if you know so much about these why aren't you working on them, and making them work for F1 Engines?

Yakeepascratchinbutitjustkeepsonitchin!

Billy G

[mojo jojo]

As far as physics is concerned, the word kinetic has to do with motion, regardless of the cause of motion - an object in motion has kinetic energy, a stationary object has no kinetic energy.

Another example:
A block is sliding across the floor (no friction) at a constant speed towards a spring firmly attatched to the wall.

|				  -------
|  /  / |  <--  |	 |
| /  /  |	   |	 |
|				  -------
______________________________

The energy of this system is entirely kinetic (the otion of the block). The block hits the spring and compresses it a certain distance.

|	 -------
|  /| |	 |
| / | |	 |
|	 -------
______________________________

The enregy is now entirely potential: the block is momentarily at rest, and the spring is at maximum compression. An instant later, the energy stored in the spring is released, and the block is accelerated to its original speed, but in the opposite direction. All energy is now kinetic again.

To word it a little differently, the moving block does work on the spring, compressing it. The compressed spring is not at a stable equlibrium position, so it wants to return to its original length. It does so, and does work on the block to accelerate it in the opposite direction. During compression and expansion, the energy is a mix of potential and kinetic. before and after the block is in contact with the spring, the energy is all kinetic. At the instant the block is at rest and the spring compression is maximum, the energy is all potential.


I've been researching piezo and other means of producing ultrasonic waves for other applications, so it's fresh in my mind.

[OOOOOOOOOOOOOO]
[OOOOOOOOOOOOOO] <-PE crystal
****************
**************** <-valve stem
[OOOOO]**[OOOOO]
[OOOOO]**[OOOOO] <-PE crystal
	   **
	   **
	   **

Applying a voltage to the top crystal pushes the valve which then pushes against the bottom crystal? True, the bottom crystal creates a voltage since an external load is applied, but this load is the load from the top crystal - the top crystal is pushing both the valve and the bottom crystal. About twice the energy has to be applied to the top crystal since there has to be enough for it's own deflection and the deflection of the bottom crystal. Say the energy required with one crystal is E, with this dual arrangement, you're applying 2E and getting E back from the bottom - still losing an amount of energy E.

And if you know so much about these why aren't you working on them, and making them work for F1 Engines?

give me a year or two...

[This message has been edited by mojo jojo (edited 03-10-2000).]

[This message has been edited by mojo jojo (edited 03-10-2000).]

[Billy Gunn]

Nice one Mojo Jojo,

OK - thanks for the explaination of terminology. I stand corrected and better informed thanks to your efforts.

The motions you imply, in the back to back scenario, are understandably flawed. What if there is a motion space between the two energy sources. This would allow the top crystal stack to 'kick' the valve into motion, and the lower crystal stack 'arrested' said motion. This would allow the recovery, would it not, of some of the 'kinetic' energy of the valve in motion?? and cushion its end travel into the bargin.

Alternatively we could look at Hydrodynamics........

Gettinthereslowlybutsurely!

Billy G

[Blackhawk]

I might be totally off here but as far as I have read F1 engines are camless and use pneumatic valves. Since this discussion is about a mecanical valvesystem, how does it apply?

[desmo]

Blackhawk, These engines use valves that are pneumatically sprung. They use steel cams just like your road car, but with much bigger bumps!

[mojo jojo]

What if there is a motion space between the two energy sources. This would allow the top crystal stack to 'kick' the valve into motion, and the lower crystal stack 'arrested' said motion

perhaps... but the displacemments we're talking about with P-E crystals are really tiny. They wouldn't be able to impart enough momentum to the valve to move it the required distance in the required time. It would take more of an explosive force. Keeping the valve pressed against one crystal until activated is another complication - how would you hold it up against the top crystal? The original idea was to get rid of springs.

Alternatively we could look at Hydrodynamics........

Ahh... but that's an entirely different thread!

[Blackhawk]

desmo, thanx. I didn't know.

On the topic about the electromagnetic valves, wouldn't the magnets, if run on a F1 engine, get a real hammering. I mean the heat and friction would probably kill the magnets. Or??