treyZ28

I read/saw a quick blurb about it in an industry specific magazine (automotive engineering)

Anyone know anything or is this another magic product with no fruitation.

Adrenaline_Z

I wonder what sort of power would be required to pulse the coil several times
per second on every valve.

With a 'normally closed valve', the spring would have to be overcome as well.
I'm sure they're not going to use 150# seat pressures, but something needs
to send the valve back to home position...gravity isn't going to cut it.

I don't think reversing the current (AC ) is an option because of the duty cycle. That will change as RPM changes too.

If it's a normally open valve, same applies, but reverse mechanics.

Then think about the shielding needed to prevent cross talk on sensor wires,
sensors, etc.

Seems like a very complex design. As always, there will be pros and cons.

Do you have a link to this article?

Keith

Watching the pikes peak hill climbs on espn2 a couple years ago, there was mention of a big rig running solenoid actuated valves. It climbed the hill from what I remember. I wonder if diesel was the only option, due to their low redline?

I wonder how far it has come along today.

treyZ28

i'm really suprised fluids can be used aid in this process. in F1at redline the valve opens and closes in 0.004 seconds (est.) i cant believe you can create pressure and they remove it that fast. makes my head boggle.

Point of this story is that the "yes" and "no" can easily be determined. Magnitude of forces and things like that usually are more difficult to estimate

bshell

iTrader: (24)

Here's an article that I found about valvetrain technology being developed by Lotus:

http://www.all4engineers.com/index.p...alloc=33/id=45

Its electrohydraulic instead of electromagnetic, but still an interesting read.

treyZ28

i calculated at 18k or 19k rpm. I cant remember.

assuming 200% VE at this point and .004 seconds (assuming peak torque isn't at redline. and i'm stubborn)

density of air = 1.29 g/liter

displacement- 3.0 liters
airflow (volume) 6.0 liters/ opening

airflow (mass) = 7.74 grams /opening

250 openings per second

1935g/second mass air flow rate. Or almost 2.0 KG OF AIR PER SECOND (its a few degrees below STP) or 7200 KG/ HR

assume 13:1 A:F (why not!)

mass fuel flow 148g/second or 535846g /hr or 535.8 KG/hr

density of gasoline = .720Kg /liter

volume fuel flow rate = 740,000 L/Hr or over 195,000 gallons/hr.

what gives here.

treyZ28

whoops, typo. you can see in the second post i used .004.

Wnts2Go10O

iTrader: (12)

hmm, since they still need springs but as to not prematurely wear out the e-mag servos, what if they actually used engine compression to help close it?

carzman5678

From what I understand, F1 cars use Solenoids to activate valves and dont run camshafts....

blu00rdstr

Actually they use pneumatic springs actuated by hydraulics, and the solenoids are computer controlled. They're expensive even for Indy cars. http://www.indiacar.com/index2.asp?p...l/pvengine.htm

treyZ28

no pressure there if the valve is open.

P Mack

iTrader: (6)

What gives is you made two math errors. 535.8 Kg/hr / .72 Kg/ Liter = 740 L/Hr, not 740,000. Also your numbers are twice as high as they should be because you used 6.0 L/opening (i think you meant "revolution", not "opening"). With 200% VE, a 3.0L engine will use 3.0L per revolution because each intake valve only opens every other revolution (intake compression power exhaust). So your real answer would be 370 L/hr or 96 gal/hr. Gotta keep track of your units.

250 revs/second * 3.0 liters/rev * 1.29 g air / L air * 1 g fuel / 13 g air * 1 L fuel / 720 g fuel * 3600 s / hr = 372 L/hr

treyZ28

good catch, thanks!

chuntington101

yes F1 guys use pneumatics! they were outawed in the early nineties i think and the peak RPM dropped to just over 10K on the V8's of the day! now they are upto 20K on the lastest (next season) 2.4 ltr V8!! the only way to get the valves to open and close that fast is using air!

as for the orignal post about electromagnetic valve gear, well i think i read a piece about it a couple of months back. it said that it requiers something like 5kw (about 6.667bhp) of power to drive the system! and that was on a single cylinder! think about the energy required for a V8!!

will try and find more info on it!

thanks Chris.

Adrenaline_Z

If this system requires about 5 KiloWatts to operate at peak RPM, I wonder
what sort of power supply would be needed (several batteries), and how long
the charge could hold? I don't think a high output alternator (or two) would be sufficient?

Since not all valves are opening at the sime time, the total power might not
be much more than 10KW?

What do the Spintron users have to say about total power needed to run
the valves?

Maybe we can do a reverse calculation based on 6.7 HP per cylinder?

MadBill

The power demands of EVA were one of the main reasons the automotive sector was eyeing 42 V. electrical systems (which seem to have faded away of late..) The first time I ran into this concept, a guy at the Sears Point CA race track early in 1986 claimed to be on the brink of volume manufacturing. His T. Bird even had an 'Eva' license plate. Can't count the number of times since it has been just months from production...

Re P Mack's 'revised' F1 calculation, if you use the rule of thumb that it takes one half a pound of gasoline per hour to make a horsepower, then 96 gal/hr. = 96 x 6 = 576 lb. = 1152 HP. A little high, but then at 18,000 + RPM, the friction might start cutting into the B.S.F.C. On the other hand, if we assume a 'slightly' more modest V.E., say 120%, and a better B.S.F.C., say 0.4, then we get 58 gal/hr. and 870 HP...

chuntington101

dont forget that F1 cars have 100%+ cyclinder filling due to variable length intakes!! very trick system that uses the sound of the vavles shuting and thries to capture the compresed air in the cylinders! and i think there is a little ram air effect aswell!

thanks Chris.