This is kind of interesting, actually. A fellow is building small four-cycle gasoline engines that use electrical solenoids to operate the valves. The idea is to permit valve timing to be completely variable. And he actually powers his R/C airplanes with them.

EVIC Engine Home Page

 

Ducati or some other italian motorcycle maker was playing with this several years ago. It never took off because of the RPM limitation associated with not having a positive mechanical device actuating the valves. They had valve float at 6000 or some ridiculously low rpm.


EDIT:

Here you go, from the horse's mouth:

http://www.ducati.com/bikes/techcafe...=faq#question2

 

that is really cool.

 

Aren't some of the F1 engines run this way with either hydraulic or pneumatic actuators?

 

pneumatic is the future, along with direct injection fuel

 

That is really awesome. I wonder if the technology can be used on a larger displacement engine to drive a scooter or mower.

 

I believe it's pneumatic, although I could be wrong. Mechanical valvetrains give up around 14k.

 

BMW started ******* with this way back in '03

A Chip-Based Challenge to a Car's Spinning Camshaft - The New York Times

 

F1 engines don't need valves. They use a compact cyclotron to accelerate the fuel and air up to the speed of light and then deposit them directly into the chamber.

Seriously though, I've wondered about this pretty much since I first learned how an engine works. Granted, it would take a fairly large, high-power solenoid to get the job done on a modern engine, but I don't see why cycle time or speed of operation would be limitations. After all, a fuel injector is just a tiny solenoid, and on direct-injection engines they're working pretty damn fast.

 

fuel injector doesn't have to move anywhere near as far.

 

Or have anywhere near the mass it has to move. A valve head and stem must have at least 100x the mass of the pintle in an injector. Imagine a solenoid enlarged at the same rate of the pintle until the pintle is as large as a valve. You have a HUGE solenoid then.

 

Size matters not. Judge me by my size, do you?

Seriously- BMW has the right idea. Increase the voltage = increase the field intensity for a given current. You wouldn't have to convert the whole vehicle to a 42 volt electrical system to do it, either. A boost-mode switching power supply could produce 100 volts to drive the solenoids easily and efficiently.

 

Very interesting concept. I'm kind of surprised no one has figured it out before, seems like it would make for some decent power/efficiency gains once it's perfected. Now how are they going to integrate that into tuning software? Haha. I guess we're going to have a couple more maps to figure out.

 

F1 use PNEUMATIC SPRINGS, but still use cams to open the valves.

BMW's valvetronic and Nissan's copycat system have CONTINUOUSLY variable lift and timing.

It's here now, guys. No need for electric actuators. These systems also don't need a throttle butterfly (other than for transients and ensuing emissions).

 

Detroit Diesel is planning to release a camless engine in 2010. It is on the road in real world testing right now. It is a modified Series 60

 

I was looking into it more and Joe is correct on the electronic valves. Looks like Renault is reported to be testing solenoid controlled valves in order to eliminate camshafts completely. Probably will trickle down into production cars in the next decade.

The #1 thing that will be tough for it in getting used in commercially available automobiles will be long term reliability. They will need to operate in the 300-400def F range for a couple hundred thousand miles. And yes cyclically operating parts in the cylinder head to reach those continuous temps.

 

**** valves, just install REALLY BIG air injectors.

and I guess ejectors.

 

Lotus have had a hydraulically operated engine valve lift running for a few years.
I seem to remember the biggest obstacle was weight and the prices of the actuators (around 20k )

View Item : » Managed Content » Lotus

More details here as well.
Lotus leads way with clean engine - News - The Engineer


Cheers
Mark

 

AutoZine Technical School - ENGINE