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Mag Valve Technology


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#1 rdrcr

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Posted 28 June 2001 - 01:30

Renault's revolutionary new F1 engine could be heading for problems. The engine employs an unusual 111 degree valve banking arrangement. A Quote from Competitor BMW Motorsport Director, Dr. Mario Theissenwhich, "This configuration will require an exhaust system that may be difficult to configure." Not to mention compromising the CG of the engine.

You can move a valve electronically in two ways. One approach (used by Renault), uses a solenoid, a reliable and well-understood transducer for converting an applied current into linear motion and static force.

However, challenges exist if you use a solenoid First, the current pulse you need to activate the solenoid with the force and speed required in this application is large and difficult to get from the 12V supply of the vehicle without heavy supply cables. You also need a hefty MOSFET or similar switch to handle the current, and the relatively modest digital output drive of the valve-timing processor must control the switch. Although this solenoid operates at a moderate duty cycle, its overall rate of operation is high enough that you face self-heating cost to the design.

Finally, solenoids are on/off actuators with relatively fixed force-versus-distance characteristics.

Without springs or other external forces, the solenoid's force is lowest initially as the magnetic field pulls the core slug in toward its center; the force is greatest at the center at the final resting point of the actuator travel. Consequently, a solenoid slams the valve closed fairly hard, which aggravates wear on the valve seals unless you use mechanisms, such as springs or other damping components.

Until they figure out a way to eliminate the force generated by the software program they will have to add reliability problems to the equation.

Real world use is coming soon however. Renault is looking at using its camless system with a solenoid actuator for some diesel cars in 2002.

Here is a great article on the subject
http://www.ednmag.co.../pdfs/02hiw.pdf

Any thoughts about Renault being able to ready this latest technology and get the bugs worked out in time for the 2002 season?

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#2 imaginesix

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Posted 28 June 2001 - 02:15

Here is a copy of my thoughts on a plausible EM Valve actuator that was originally posted on the Technical forum at technicalF1.com.

Read the entire thread at:
http://www.technical...forum=1&start=0

Here's my thinkie:

Instead of using a spring to close the valve and a cam or electromagnet to open it, why not use a spring for both opening and closing events?

When the valve is opened, the spring would act on it as usual to push it closed, but only half way. The valve would close the rest of the way due to inertia. As it closed itself, it would compress another spring of equal strength, that could then be used to push the valve open again later.
Such a system would require some kind of locking mechanism to hold the valve in the open or closed position, until the lock was timed to release, letting the springs do their job.

This valve actuation method would require no energy draw from the engine to accelerate the mass of the valve, which is the achilles heel of electromagnetic actuation, it seems. The only energy it would require would be that needed to overcome the friction of the valve and to actuate the locking mechanism.
An electromagnet would be well suited to the job of overcoming the friction drag of the valve, in both the opening and closing events.
The stiffness of the springs could be increased hugely in order to speed up the movement of the valve without costing anything in energy consumption.

The only concern is that it might be ridiculously easy to 'drop' a valve, since the valves would effectively have been 'thrown' back and forth between the open and closed position, with no ability to recover them if they don't make it to the other side!!!

I must be overlooking something because it seems like such a simple solution. Anyone???


Any thoughts or objections are eagerly welcomed.

#3 imaginesix

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Posted 28 June 2001 - 02:51

Seems I'm always one post behind.

Having just read a bit of the first SAE paper that desmo presented, I see some mention of a 'two-spring' system, and a comment regarding a problem with the high seating velocity incurred by such. If this is the same system I described above, then two issues may exist: the noise of the valve being seated and the strain of the impact on the valve.

Depending on the severity of these problems, the concept may still be plausible for a race car, where noise and longevity are less of an issue than in road cars. In fact I remember hearing that Honda once made an F1 engine whose valves would float by design, simply because they didn't need to last more than a race.

Comments and insults are still welcome BTW.

#4 desmo

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Posted 28 June 2001 - 05:39

Imaginesix, I've recently seen a drawing of a system similar in concept to what you've described but for the life of me I cannot remember where. Sounds conceptually similar to a automatic knife I had years ago that had the blade flick straight out from the body at the light push of a switch. The cool part was it would retract the same way with the forceful opening and closing action seemingly out of all proportion to the force of pushing the switch. Finally curiosity got the better of me and I disassembled it to see how it worked and found a clever overcenter mechanism with two opposing springs.

#5 rdrcr

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Posted 28 June 2001 - 15:19

After reading that thread link from Imagine's post and some other material. I think that the problems lie in the solenoid actuators and the timing. A good observation was made regarding sensors. They would be critical to locate the crank and relay it's exact position to the CPU that tells the mags where it is and its relationship to the valves and the valve actuators.

Anyway, this solenoid mass on top of the engine, its 111 degree configuration and the compexities involved must be what the engineers are struggling with.

Here is that link to the short Peter Wright article.

http://www.grandprix...ft/ftpw012.html

There was a previous post Question about Renault's 111 V10 http://www.atlasf1.c...&threadid=16391 .

Desmo, you stated that at the time that was written the Renault engine was still using cams. Do you still think that they are and this EMV technology remains in their R & D dept?


Regards -

rdrcr






P.S. Internal combustion engines are so inefficient. You know, why not get a small turbine and generate power to all 4 wheels via electric motors. Huge torque, and linear power curve, You'll just have to "fabricate" the sound and pump it out speakers from the engine compartment... as the fans would miss the noise! You may think I'm nuts or whatever but this powertrain would really kick some ass...

oh never mind....

#6 desmo

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Posted 28 June 2001 - 17:09

Aftr seeing drawings of the engine it is definitely a conventional 4 cam design. I really don't know who may or may not be developing camless engine technology for F1, the problems are formidable. I would be mightily surprised to see any applications in high rpm motorsports in the next five years.

#7 palmas

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Posted 29 June 2001 - 15:26

Originally posted by rdrcr
.

P.S. Internal combustion engines are so inefficient. You know, why not get a small turbine and generate power to all 4 wheels via electric motors. Huge torque, and linear power curve, You'll just have to "fabricate" the sound and pump it out speakers from the engine compartment... as the fans would miss the noise! You may think I'm nuts or whatever but this powertrain would really kick some ass...

oh never mind....


Sorry, turbines are not as efficient as combustion engines (at least not today). The only advantage is power/weight ratio. Nevertheless I like the generator-electrical engine configuration (like trains and Ward-Leonard variators).
Torque is not huge (is smaller than comb. engine top torque) , it is however quite constante until nominal speed, then it decreases linaearly (power is constant). And that is the case for the most comon electrical engine...

#8 Top Fuel F1

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Posted 29 June 2001 - 21:05

Originally posted by rdrcr
Renault's revolutionary new F1 engine could be heading for problems. The engine employs an unusual 111 degree valve banking arrangement. A Quote from Competitor BMW Motorsport Director, Dr. Mario Theissenwhich, "This configuration will require an exhaust system that may be difficult to configure." Not to mention compromising the CG of the engine.


I guess we have been talking about the Renault 111 degree engine block and it's associated exhaust puzzle for Months now. Also with a great amount of speculation about the possibility that it may have Electromagnetic (Active) Valves. However I thought we had kind of concluded that it probably did not have Active Valves by this time. I guess there is a wish that they did, in that anything new and revolutionary would be exciting. Associated with the difficulty of having this is best illustrated by something I previously posted:

Re: Interview with Mario illian (Current Mercedes/Ilmor F1 V-10)

Ques: With the valve lift increasing and the valve to piston clearances decreasing is there now a case for active valves?

Ans: Mario says "No chance ! ". He points out the enormous power and accuracy that would take. He says they have a dynamic clearance between the piston and valve in the area of 0.2 mm. He goes on to stress that the means to control the valve to maintain this is a great challenge and does not think active valves are a
possibility with current technology. In any event the main factor in his mind of discounting the use of active valves is the great amount of energy it would take to open and close 40 valves. He goes on to say "it's not worth considering".

Rgds;

#9 rdrcr

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Posted 30 June 2001 - 03:14

Top Fuel.... You'd be correct. I saw the Thread about the Renault 111 V10 and there was so much in there that I must have missed your post, or if I saw it I just lost in my tiny brain....

I suspected from the onset that this latest technology was running into problems and that I wondered if it was in fact being used currently or tested in the R & D dept or what...

I think we've come to the conclusion that this technology is fraught with problems of weight, reliability and configuration. It was a valient effort though in the reduction hp loss within the engine.

Thanks for your input.

Regards -

rdrcr

#10 Melbourne Park

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Posted 04 July 2001 - 08:07

Originally posted by palmas


Sorry, turbines are not as efficient as combustion engines (at least not today). The only advantage is power/weight ratio. Nevertheless I like the generator-electrical engine configuration (like trains and Ward-Leonard variators).
Torque is not huge (is smaller than comb. engine top torque) , it is however quite constante until nominal speed, then it decreases linaearly (power is constant). And that is the case for the most comon electrical engine...


It would be nice to transfer, by electrical or mechanical means, the braking energy into stored energy and then use it for accelleration. Honda and Toyota's duel econo cars do this, it would be great to have a more open formula that was based on fuel consumption rather than very arbitrary rules. I would imagine less downforce and very high straight line speeds, and with less grip and downforce lots of overtaking. Plus some light weigth and clever ways of transferring the braking energy into forward motion ... i suspect springs or spinning disks would be more efficient than electrical storage ... one can only dream ...

#11 palmas

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Posted 04 July 2001 - 10:50

Melbourne Park, also I would like to see a formula made for fuel saving - like a mix between F1 and 3000km-with-one-litter-of-fuel race.
But thats not F1!
Actualy in F1 fuel ecconomy has some effect on performance (less weight and less time on pit). Maybe they could increase this effect...

#12 Melbourne Park

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Posted 04 July 2001 - 12:09

Yes palmas I am sure that if power retention was legal the teams would use it. The cars are already ballasted and the amount of power that is lost through braking must be immense. Spinning disks might even provide interesting stability benefits; certainly springs could be wound by braking and released on the following corner. Besides fuel benefits there would be a significant increase in available power I would have thought. More restricted fuel would also result in less downforce I would have thought, which would result in more interesting racing ...