Old SStroker

Solenoid operated valves (SOV) require a significant amount of electrical power to operate, perhaps equal to all the rest of the systems on your car. They aren't able to cycle fast enough for ultra fast engines like F1, and the extra weight is carried high and wide on the engine. They will be very costly to produce and generate significantly more heat under the hood than current engines (no pun intended )

I still fail to see the overwhelming advantage of SOV. Even if they could produce a "square wave" valve motion, which they cannot, that isn't at all ideal for breathing. Varying lift can eliminate the need for a throttle, as BMW has shown, but why bother? Variable phasing, especially with multicam engines, goes a long way toward optimising engine output.

I would rather see variable length intake runners to shape the torque curve (along with cam phasing). It worked well in F1 until it was outlawed for 2006. Renault, especially misses it this year.

If we are going to take something from F1, pneumatic valve springs sounds good to me.

We already produce OEM engines (gasoline, NA) with torque curves having 90% of max torque from converter stall(<2000) to WOT upshift point (>5500). We're headed toward an almost flat torque curve with current technology.

FWIW, flat lifter pushrod engines (NASCAR Cup, for example) have almost point contact between the slightly radiused lifter foot and the slightly tapered lobe. That point moves on the lifter, but the loads are very high, and they live, just as flat lifters lived in OEM engines. That's not really a hurdle lto 3D cams.

DavidNJ

Actually, you probably wouldn't operate the valves electrically. You would operate a valve that would change hydraulic pressure that would move the valve. You're control over the valve may use valve displacement as an input. A 1-1.5 in² disk mounted on the valve with a 600psi pressure should get the desired valve movement. The valve would be adjusting the pressure differential across the disk.

DavidNJ

None of this has to do with the original question, which could probably be implemented in existing pushrod engines.

HPP

Perhaps not, but it's very (if not more) interesting.

Old SStroker

Interesting concept. The plumbing might present a problem however.

A 1.0 sq.in. disk moving .650 in. @ 7200 rpm with a 300 degree (seat-seat timing) duration needs to move the hydraulic oil at a rate of about 48 gallons per minute with no restriction and with a control making changes every 10-40 microseconds (not milleseconds). This is for each valve. That might be a fairly large challenge. Perhaps I missed something.

DavidNJ

Think brake system in contrast with lubrication system. Since there is less mass and no extra energy stored in the spring or disapated in valve spring heat, the power should be lower than current cam driven open, spring driven close valvetrains.

Old SStroker

Yeah, I was thinking of a closed hydraulic system. ABS or my foot is fast but even I can't pump the brakes in 7 milliseconds (on and off), and do it accurately 60 times a second. Well, I probably can, but the hydraulics can't keep up with me.

Dig a little deeper into hydraulics and their controls.

joecar

I agree, I think low power solenoids controlling high pressure hydraulics is probably the good way to go.

Old SStroker

I guess I'm being too subtle. Hydraulics ain't going to hack it, guys.

Perhaps we could use tiny CNC ball screws.

Cop Car

iTrader: (14)

BMW already has a camless V10. its in the M5 and M6. valves are actuated by solenoids. its the future, and i cant wait till all the kinks are worked out.

cantdrv65

iTrader: (3)

It ain't fast enough.

Old SStroker

Yep. I was trying to make my point the hard way.

Thanks.

DavidNJ

Maybe my pressures are off...this is roughly analogous to the time fuel is injected. Also a non-compressible fluid system.

pianoprodigy

iTrader: (1)

Interesting stuff!

joecar

How is BMW doing it...?

Old SStroker

There's a big difference between squirting ~.07 cc of gasoline into an open space and pumping 150 times as much oil @ 500+ psi to open (and the same amount to close) a valve with virtually no restriction. Remember this needs to be a double-acting hydraullic system for each valve. My rough calculations say you are moving about 1200 liters (317 gallons) of oil per minute at 7200 with a 16 valve engine (2 valve V8), or twice that for a 32 valve V8.

I'll leave it to others to figure the pump power, oil tank capacity and cooling system needed to make such a system work. Note that we don't see a lot of hydrauliclly actuated valve on high speed IC engines.

Shoot, high-revving F1 engines couldn't make electrical solenoids work fast enough, and the weight (high up) and electrical power required made the systems impractical even before they were ruled out.

UofMN

iTrader: (1)

Another big problem there would be with a SOV (solenoid operated valve) is the need for a soft landing of the valve in the seat. If you just slammed the valve shut against the valve seat you would destroy it quickly. Without showing any numbers and proof I don't think anyone can dismiss either an electrical or hydralic system.
UofMn

LTSpeed

They have a camshaft. It's very much like VTEC, with a couple of very expensive actuator gimmicks thrown in...

Camaro_Z28

I didnt read the whole post so I'm not sure if this was already mentioned, but GM does have a variable cam timing in-block cam motor about to be released. Its The 6.2L vortec coming out in the yukon denali. It has an actuator on the cam that can advance or retard like 60 degrees or so. It also has displacement on demand so its rated in the low 20's on gas mileage and makes like 430 HP or something like that. So they are one step ahead of the game, I cant wait to drive one.

BAD ASS TA WS6

iTrader: (5)

BMWs system uses their Valvetronic system on the E65/66 V8/V12 cars. Also the E53 X5s w/V8s, and E60/63/64 5 and 6 series V8 cars.

Valvetronic = intake valve variable lift adjustment

Intake air flow is set with the throttle body fully open, and by adjusting the valves on the fly.

Intake/Exhaust cam for each head (4), with an added eccentric shaft higher above and off to the side of the intake camshaft. Two DC motors adjust these shafts.

The throttle body isn't even used 99% of the time. At start up, the throttle body controls air flow. Air flow is also controlled by the throttle body if any faults are to occur in the system.

Ex.
In the event of a motor failing, the motor on the opposite bank will match the failed motors position.

Pretty bad *** setup. Sounds like a lot to go wrong, but so far this has been pretty reliable.