I have an old friend that is an engineer for Chrysler in Detroit, and he told me about an interesting project that they have been working on. He claims that there is a good bit of research being done on a new 42 volt eletrical system for the cars of the future. The biggest of many reasons to use the 42 volt system would be electric engine valves. Yes - you read that correctly; electric engine valves.

Some of you may have heard of this before, and I remember it being mentioned in one of my engineering courses at Penn State. There is also some other components that they would like to make all-electric, such as the A/C compressor.

There are obviously alot of benefits that an all-electric valvetrain can offer: You could completely eliminate the camshaft and associated lifters and pushrods. More importantly, you could allow the computer to completely control the valve operation - valve timing, lift, and duration could all be controlled by the computer. The more I think about this the more interesting it becomes. You could literally change your valve operation at the push of a button on the dash. Dial up an aggressive profile for racing, and then dial up a fuel-efficient profile for the trip home - all at the push of a button.

One main reason that we have not seen this already is because the current 12V system will not support the operation of the energy-greedy electric solonoids that would have to open the valves. Also, it is not an easy task to develop an electric solonoid that will operate reliably at the speeds required by the engine.

Regardless of the engineering problems and setbacks, it is still a very interesting concept with alot of potential. Just food for thought guys - tell me what you have heard and what you think.

 

sounds pretty cool!

 

Havent heard that, but the thought of that is f'ing awesome. All the benefits of a monster cam when you want it....and then 30 mpg on the way home...thats beautiful. The tuning posibilities are rediculous. Im gonna go zone out at work for a while now thinking about that.

 

I think there was a thread a while back about Lotus(?) or a like company was developing a solenoid actuated valvetrain.
I do believe that F1 uses air actuated valves, which would be a step in the right direction, to camless valvetrains. I don't know how F1 works (I can't find a good tech article) so the acuaters may be different.

I think the biggest problem will be reliability and cost to replace a broken component.

I wonder if we will be able to make the valve smaller/lighter with the solenoid technology?

It sounds great to be able to go from a Stealth II cam at 2000 RPM to a TREX cam at 7000RPM with the infinite adjustability of the electrically operated valve.

 

I remember reading about electric valves being worked on by BMW for their motorcycles some years ago. This would be similar to the transition from carburation to fuel injection, and likely have a similar adoption rate. I wouldn't expect to start seeing this in production vehicle for at least 5 years, and perhaps longer, and it won't become common for another 10-15 years after that. The flexibility it will provide to intake and exhaust timing will be tremendous though. Push of a button? Not even that. It will all be automatic, requiring no input from the driver other than how much throttle he chooses to give it. You'll have a seemless transition from cruise to ***** to the wall.

Take a dozen dyno runs from a dozen different cams that cover the spectrum of low end torque to high end breather, overlay the torque curves of all those runs and take the best torque from each RPM, and that's an idea of the kind of flat and wide powerband such an advance would be capable of providing without sacrificing idle or partial throttle drivability at all.

 

some exotic cars already come with solenoid actuated valves. i think lamborghini has a car out now with them.

 

Very intriguing to say the least. The possibilities of electronically controlled valves would be endless. Can you say a cam swap done in one second? However, I think we are stuck with camhafts for awhile before this can be done reliably and repetitively for hundreds of thousands of miles.

 

It seems that there are already a few companies that have developed electric operated valves:

http://www.fev.com/content/public/default.aspx?id=537

This pic from the website shows the basic electric valve setup:



The main challenges seem to be in the switch from 12V to 42V car electrical systems. Apparently there are power generation and safety concerns that still have to be worked out.

 

F1 engines still use a camshaft to actuate their valves. They have done away with valve springs and use air to return the valve . The system is called PVRS(pneumatic valve return system). You should be able to find tech articles if you search pvrs. A valve spring stiff enough to close the valves at 20k would never survive an hour and a half, let alone two race weekends. Look at how long Pro Stock springs last. We were working on a pvrs in prostock when the NHRA preemptively banned it.

Al

 

i have heard about that several years ago. I think it is possible when every manufactor gets involved. Now days ther is no true Chevy, Ford or Chrylser.

BMW came up in 02 w/valvetronic. It has cam camshafts in each head. At idle the valves only open the thickness of a sheet of paper. For the past 4 years of production I have only seen one actuator go bad. The TB is only there for failsafe. Once engine cranks the TB opens completely. Try a search its out there. Think about a 380HP 750 that weights about 4500 lbs gets 26-28 MPG on the highway, now that is cool.

Just a little more food for thought.

 

Apparently long term electrical switch life has been a stumbling block for higher voltage dc car systems. When switches are closed, the resulting electrical arc erodes the contacts at a substantially faster rate at 40+volts than at 12v.

 

I'd like to see an LS motor with a spherical/rotory valve head on it . High RPM and big cubes Yeah baby ! ok back on subject. The cool thing is with these electrically operated valves is that you can change your cam profile with the mere click of a mouse ( theoretically) . Or better yet a switch that allows you to select between milage or all out power. Will be cool to see this technology develop. I just hope the tree hugger's don't force electric boring-mobiles on the populous before this tech becomes developed.

 

The "switches" will be solid-state devices (transistors) so there won't be any contacts or arc.

 

IMHO I think the auto industry made a mistake when the went from 6 volt systems to 12 volts systems. I have always thought that they should have went to 24 volts. Now it looks like 42 or maybe 48 volt may be the norm. Whatever the next voltage is they need to get away from 12 volts.

 

I wasn't referring to the valve actuators as switches. I was referring to switches and relays in the rest of the vehicle. Ignition, window, and door switches, for example, are all still part of the total vehicle package that would be affected by higher DC voltage. Higher voltage does have the side benefit of allowing for smaller electrical wires, saving weight and money.

 

OK, but the topic is supposed to be electrically actuated valves.

 

I'm just trying to point out why something that on the surface seems so simple isn't in widespread use already. The very thing that would allow valve actuators to work better (higher voltage) has proven difficult to implement as part of the total car package.

 

That wouldn't make sense. Properly tuned, your idle would be smooth as glass, your light load stuff would be as efficient as possible and as load increased, the valves behavior would change based on what your right foot was asking for (as well as RPM and a lot of other factors too). You also wouldn't need a throttle butterfly anymore, just a means of filtering the air...but there'd be no need to have multiple tunes.

Cams will never be "extinct"...they're so cheap to make (when a facility is setup to make them), as long as there are internal combustion engines in cars, some will use camshafts.

 

My statement about "pushing a button on the dash" was just symbolic of having the ability to instantly change your cam profile. I agree that camshafts will probably never become extinct, but they may become the second choice in valvetrain operation sometime in the future.

 

i think i heard that 48v was the original plan, and something about a possible safety issue where 42v is already going to shock you if you touch both terminals like you can easily do on a 12v battery, 48v was just enough of an increase that it would actually shock the **** out of you just enough that even with rubber gloves you'd feel it and it would hurt...thats all hearsay though...