First of all I rarely post anything on the boards here, but I read them everyday. So you all probably don't know me, but I thought I'd post this anyway. Secondly I don't know if this belongs here or in off topic so feel free to move it.

I was just thinking today about engines today and I think I may have come up with a good idea.

What if in an engine you could rid of the camshaft/s. I think you could use computer controlled hydraulic actuators instead of a camshaft to open the valves in an engine. The benefits could be great when you think about it. Your engine could be fuel efficient one minute, and fire breathing the next...

The neccessary hydraulic pump could be belt driven, or perhaps electrical. I don't know if the absence of a cam would make up for having another engine driven accessory or not, or if the extra weight would be worth it, but I think in the end it's an idea that could lead to another big advancement for piston powered engines.

I don't know how sound the whole idea is, or if it's already been thought up before , but any input or ideas I'd love to hear.

 

Eventually you will probably see something like that, but even in F1 right now there all still camshafts. They have eliminated the valve springs however by using compressed air instead. The valve spring was always the weak link anyway.

 

bmw is hard at work on this one, you really cant lose with it.

a camshaft really only has a certain effect on a small range of rpm's whereas computer controlled actuators can go across the whole spectrum.

btw: you sound like someon that would like to read popsci (thats where i read about the bmw system)
franklinz

 

I think they use hydraulically actuated valves on some new truck engines (large diesel SEMI engines) because they typically run below 2000 RPM. The problem with the hydraulically actuated valve system is the activation speed. You need a system that can operate extremely fast, and I think that is currently the limiting factor.

It's definitely a very good idea, because it would basically allow truly variable lift and timing, which could all be adjusted via programming. It would be a tuner's dream.

I haven't read about this for a couple years, so my info may be out of date.

-D'oh!

 

I'm gonna have to say it comes down to speed & long term reliability. I'm sure someone could develop a short-motion hydraulic or actuated system, however you gotta figure over the long term its a helluva system. Take this hypothetical:

3000 rpm
x
1 hour driving
=
180,000 revolutions / hour. Mind you during each revolution has to result in the firing of 6 individual cylinders (assuming V6). That means 6 individual hydraulic systems, each experiencing 180,000 motions, totalling 1,080,000 actuations per hour. Flawlessly. Not to mention that this is a loss-generating system - unlike a camshaft which operates using rotational inertia, this basically makes each cylinder independent. Unlike a cam system where all 6 cylinders assist in the generation of motion, each cylinder in this case has to take care of itself.

Now what I could see as a sexy option is a self-adjusting, electronically controlled camshaft. Imagine instead of the camshaft being a solid piece of metal that each part of the cam could adjust on the fly - effectively what you're saying, only still using the beneficial rotational effect of a camshaft. I'm not an engineer, so I wouldn't be able to begin to fathom what it would take to make this happen, but exactly what you're talking about - being able to switch the valve dynamics on-the-fly from the camshaft.

But the hydraulics are an interesting thought, nonetheless. Unlike buying a 1st year Z, I would NEVER buy the 1st year of one of those systems. Here's another hypothetical:

12,000 miles per year
x
3000 rpm average (aka 180,000 rph)
x
60 mph average (not likely, but anyways)
=
36,000,000 rotations per year (avg)
x
6 systems
=
216,000,000 actuations (or better yet if you assume an intake & an exhaust hydraulic system = 432,000,000 actuations)

That'd have to be pretty damned reliable for me to buy it...

 

I have a better idea for getting rid of a valvetrain. We could make the entire combustion chamber a squished oval, and put a triangle in it that would spin around through different strokes... oh wait.

Chrysler has also done R&D on on valve solenoids. Although I think it's a great idea, we probably won't see it in application for 15 years.

By the time I'm expecting the technology to be displaced by hydrogen vehicles. Sports cars will continue to be internal combusion though, and would be great candidates. The most demanding candidates though.

It would make VTEC completely irrelevant.

 

A while back I read an article talking about electromagnetic valves.
They had a running motor out of the consept but it was really noisy and had a low rpm limit.

 

Several F1 teams have been working on this for years. Rumor has it at least one has a working prototype that operates at high RPM, 10k+ RPM. I would be wiling to bet Honda has this first. Nobody can touch Honda's R&D. For those who don't know about Honda, just read up a bit. Sometimes people who don't know any better will speak out when comments like this or made, but anyone who knows anything about racing knows Honda is a force to be reckoned with.

 

Well, so I guess my idea wasn't orignial after all. I didn't think it would be.

Reliabilty would be a big issue on a system like this. You'd have a whole ton load of parts that could fail. The idea about the camshaft being able to change is interesting.. Maybe something like a multi VTEC could be used.

About the hydrogen powered cars, if they pump out 675 hp or whatever it was on Minority Report, Im all for them.



franklinz - you happen to remember which issue that was? I subscribe to Pop Sci but don't remember seeing that article.. Was it recent?

 

There is already a better alternative to the traditional poppet valve technology. George Coates origionally designed this with the automotive market in mind, but quickly realized that industrial motors and deisel, and natral gas motors are where the money is at. I can't figure out why no company has adopted this technology yet. I think for $10,000 he will adapt this to any engine. Hint hint, all you rich guys! Check out this article:

http://www.projecttransam.com/coates.asp

 

Another benefit is the elimination of the throttle. If you want to idle, the computer just barely blips the intake valves open. This is a big benefit because having a butterfly throttle plate in the airstream is a horribly inefficient thing at all throttle openings except for the wide open. And even at wide open there is still the pivot bar of the throttle plate obstructing airflow.

There is a push to go to 42 volt electrical systems in cars in the near future. Once that happens there will be enough electrical energy available for a solenoid actuated valvetrain system. It's coming, the benefits are too large for it not to.

Desmo

 

the 2007 corvette zo6 is probally going to have a camless engine pushing 500-550 hp

 

rotary engines have no valves

 

All car manufactures already have that in the works. My friend is an Acura A- Technician and he told me about it 2 years ago. Acura\Honda has been working on it. It is just like the CVT transmission. They took over 5 years to come to a production car. My friend also just got back from Acura school which he goes 2 every 6 months and was telling me about how the new ECU are flashable. If you are having a problem or ecu is sending code he can flash the ecu and again to not show the code, but still tell him what is wrong. The new ECU are going to have a data log feature so say your car is acting funny but never when dealer looks at it. They turn data logging on and they have you drive for a week. This will then allow then to figure out what is going on.

my 2 cents....

thanks,
Greg

 

I think the way manufacturers like BMW are trying to do this is electromagnetically. The problem is that it is extremely heavy and wouldn't be a greater benefit than traditional cams at this time. The benefit is that they are infinitely variable. And I agree with the above comments, from what i read they have to do it electromagnetically b/c other methods can't move fast enough.

I seem to remember that F1's pneumatic valves only worked when closing the valve? I could be wrong but that sticks in my head for some reason.

 

The thing that Turbo03 briught up about the datalogging in the ecu is a little scary. Think about it, OEMs will eventually start monitoring all kinds of perameters, and denying warantee claims on cars because of people driving them hard, or tuning them for better performance. Sounds like "Big Brother" watching over us even more closely than with OBDIII.

Also what do you guys think about the rotary valve thing I posted? If I had money just laying around I'd be really tempted to take a VQ engine up there and let them make me a set of heads!

 

Lots of companies have worked on novel valve actuation schemes for decades and the work continues. The goals are to increase peak engine speeds for racing, increase air flow at all speeds, give infinately variable valve timing and lift, eliminate the throttle valve and the ability to shut off individual cylinders.

Pnuematic valve springs- these allow the highest engine speeds currently available. Still use a conventional camshaft for opening. The advantage is low mass and no spring destroying resonances. Only used by F1 at the moment - 18,000+ RPM!!!

Electrical valve operation- requires lots of electrical power, 42 volt operation or higher, noisy (hard to keep the valve from crashing back into the seat), limited speed capability. I don't think this one will ever fly.

Hydraulicly actuated valves- these are activated by pressurized lube oil that is controlled by electric solenoid valves. Very similar to existing heavy duty diesel unit injector technology and ABS brake technology. More efficient than pure electric operation and capable of higher engine speeds but still limited. This will see life before too long, BMW may be first automotive application.

Replacing poppet valves- Wankels do it best! Many, Many designs used over the years. Fascinating WWII sleave valve aircraft engines, rotating disc valves, etc, etc. They almost all have fundamental sealing and oil consumption problems that make them impractical for high life and low emissions.

There are huge technical hurdles involved in replacing known technology. Just look how much trouble the marine industry had bringing the conceptually simple direct injection 2-stroke outboard engine to market. What seems like a good idea on paper frequently doesn't make it out of the laboratory due to some "small" problem like cost, efficiency, durability, emissions, etc. The modern internal combustion engine has been refined by hundreds of companies for the past hundred years.

I love unique engines, particularly 2 strokes and Wanklels but as someone else said earlier, I'll pass on all of these new ideas until they have been in production for at least a decade.

 

TonyZXT - I think that rotary valve idea sounded great.. I read all the info on http://www.coatesengine.com/ and it seemed like a great idea. There was something on the site stating a Ford 5.0 made 480 hp with the system on an otherwise stock engine. That's a big jump. Plus, the engine was able to rev to 14,000 some odd RPMs...that's impressive.

If I had the money I'd be putting that on all my cars.

I also liked the fact that oil changes went from 3000 miles to 50,000...

 

The coates article is pretty interesting but written in'99. Anyone know what's happened to them since then?? Anyone using or racing this system.

Also, without the cam will you get the rumble????

 

I think what happened with Coates is that he was able to make good profit right off the bat by using his technology in large industrial motors. He has also used them on some kind of natural gas fueled motor, and I think a deisel application for semi-trucks. I'm not sure whether he still intends to use it for racing or not, but I have to imagine that it will end up in cars at some point if the design is as good as it looks. I really think his design seems like it is sound. I don't know of anyone that has actually tried it for racing. Probably because it is unproven in racing, and expensive to buy. If someone in the import drag community had the guts to try it they might OWN the series. Then again it could be a big flop. I guess we'll have to wait and see. Maybe Tako will try it out on his 350Z!