Coates Rotary Valve System
 

A Long read but an engine that can tke over 14000 RPM's is a good read in my book

I've heard the retrofitted it to a 5.0L ford engine.....if I could find a set I would soooo buy them (if they where reasonably priced)

yea if they could adapt it for my 4.6 I would also be on it in a second

Been around for a while. None of the big manufacturers are taking the chance yet, bums. I've heard a rumour that a coupla big engine makers (for semi's) have been looking at these. Given the numbers you see in the big engines, the efficiency upgrades the Coates system provides means big savings.

The nice part about this is that really good tech that makes it well in big trucks, eventually trickles down to the car market. The really slick turbos being produced these days learned reliability tricks from truck turbos.

Pray to the Car Gods that we see these produced for ANY car engine on ANY sort of scale. You can get them, in theory, from Coates Engineering, but they are supposed to cost around $5k - $15k from what I hear.

The idea of rotary valves has been around almost 100 years I think, but its always had unsolvable lubrication problems. I'm skeptical that Coates has fixed this.

I'm also doubtful of the examples. I've never seen any 3rd party verification of their claims. This article talks about revving a 5L engine to almost 15,000 rpm - that's ridiculous. The engine would self-destruct. Flame propagation would also be iffy at the speed no matter what the valvetrain is. F1 engines rev that high, but I doubt these guys made something like that just to show off their system.

If it is true, then that explains why there's no dyno numbers on that engine. They just revved it until it blew...

Poppet valves, if not activated with hydraulic systems, must have clearance readjusted periodically.

ahem, bullshit.

That's why we invented hydraulic lash adjusters. Oh, they said, "if not activated with hydraulic systems." This statement is just meant to imply an adjustment problem with regular valves.

Lessse, a 5.0L (assume ford? stock? that's what they seem to be implying) revving at 15k is impossible for reasons other than the normal valvetrain. The piston velocities at such an insane speed would: (and take your pick, any is just as likely as the next...)

Send the piston flying off the connecting rod.
Snap the rod like a cheap stick.
Melt the main bearings.

While we're at it, let's dig some more BS out of this article.

Gas, auto engines in the 70s, lead or no, NEVER made anywhere near 55% thermal efficiancy. The BEST desiels today come close to that level of efficiancy. Gas today gets you 20-odd %, that's the best ones.

Lead was used to raise the octane level, which allowed for higher compression ratios. This had NOTHING to do with the valves.
The valves, specifically the seats, were designed to take advantage of the lead in the gas for use as lubrication. Not the main source of lube, mind you, just take advantage.
Remove the lead, remove the advantage, thus some redesigning was in order.
This was in no way a "failure" in the poppet valve concept, as the article implied.
If everyone was putting a magically cheap 120 octane gas in the tank, compression ratios could easily jump up to 15:1, with poppet valves working just fine.
In fact, vehicles adapted to burn natrual gas do take advantage of it's higher octane, and DO run 14:1 and the like ratios.


"The air traveling in through the inlet venturi of a combustion engine inlet travels at a speed of up to 450ft a second. In normally aspirated engines this works fine, but in poppet valve engines, the BHP and torque decreased as the air traveling in does not increase in speed unless a turbo or supercharger is incorporated."

This statement is essentially meaningless. Really, what the hell are they even saying? What works fine in a naturally aspirated engine? The speed of the intake air?

I've never worried about air inlet speed when building an engine. I don't know who has.

Air speed is a non-issue, air flow is. The size and shape of ANY inlet and outlet must be carefully designed to make air flow smoothly, I have no idea how air speed is a factor here.
While we're at it, forced induction systems to not increase the speed of intake air. They increase the volume of air inducted. That's why turbo/super chargers are both just AIR COMPRESSORS. That's why they have COMPRESSORS, to force more Cubic Feet/Minute of air into the intake.

"At higher RPMs the poppet valve tends to float or bounce and is unable to service the cylinder and chamber to capacity with air and fuel mixture."

That's why engines HAVE redlines. Beyond a certain RPM valves do float, this is bad. This is also a valve SPRING problem, not a valve type problem. If you want a high RPM ceiling, you build an expensive, lightweight, strong valvetrain. Then you can rev higher without float.

I'm not going to deconstruct the rest of the article, but it's full of shit, and that make me seriously doubt anything they may be on to here.

more info here...
http://www.coatesengine.com/csrv.html

billege, Im not taking issue with your refutation of the article. however, you do seem to ignore the very essence of the Coates system, which is that it eliminates the excessive waste of the traditionaly poppet valvetrain.

lets face facts. the poppet valve setup, regardless of whether it uses hydraulics, is an overly complicated system. IF (and thats a big if) the CSRV has solved the sealing problems, then it simply has to be a superior system.

less moving parts = less weight + less friction= more power output



"That's why engines HAVE redlines. Beyond a certain RPM valves do float, this is bad. This is also a valve SPRING problem, not a valve type problem. If you want a high RPM ceiling, you build an expensive, lightweight, strong valvetrain. Then you can rev higher without float."


or you might just eliminate the valvetrain altogether, as Coates appears to have done.

I ignore anything that comes packaged with that much BS.

If they have a superior system, more power to them. I think everyone appreciates design advances, especially those that gain power and effeciency.

However, if they have a credible project, it wouldn't be cloaked in a sea of BS about poppet valves.

Well, I would call that a hydraulically activated system, essentially. I've owned a number of pure pushrod engines, and they were a stone cold bitch to maintain at peak tune. The bike engine I'm working now is a pushrod engine and it's pretty much standard practice to have spare tappet covers in your tool box as they have to come off so often that you will lose/break them. Valve adjustement IS a problem with poppet valve engines, it is just less of a problem with hydraulic ones (this is not to say that Coates valve would not take some sort of adjustment, but it seems like that is done by the designers and stays as is, a possible weakness of the system, really)

Quoted from the article "A five-litre poppet vavle engine tested on a dynomometer under the same loads and conditions at 5500 produced 480 BHP and 454 foot pounds of torque." I really cannot recall a stock Ford, or any other, 5.0 litre engine producing 480bhp. So, not a stock engine, I would assume. I would, however, agree with the surmise that the engine grenaded at 14k rpms. It just seems unlikely, then again, they could have used F1 quality components and design that could take such extreme rpm.

While air-flow is important, speed is also important as it becomes a major factor in turbulence. Too much speed is due to overly opened ports/runners, and accompanied by too little turbulence causing poorer quality mix. Going back to the bike engine I referred to earlier, in the CB750, one of the classic head tuning tricks was to open the intake ports as wide as possible. I've seen rock-solid data that show this to be a bad idea as it allows too much speed and kills mix. It is better to D-shape the port and make a flat-spot, slowing down the mix and increasing turbulence (while keeping similar cfm numbers if done right).

Moving back to the article though, speed can denote many things. To an untrained person reading a basic article in a non-automotive publication, speed can easily be a (poor) substitute for cfm (speed being distance travelled in a given unit of time, but can also refer to simply how fast a given action is performed, in this case movement of air per unit of time). This is a basic article intended to give an overview of the Coates system to someone that is likely not terribly familiar with autmotive engineering and design. It is not an article written by a car guy for car people.

Um, valve float IS a problem endemic to poppet valve engines. It is a big problem. There is no real way around it either. This is what the Coates system is designed to prevent. I have my problems with the article as well, but the theory is sound. If you research the idea a bit more, you'll likely find that this article is simply poorly written due to its' intended audience.

Right, that's what turns me off to the idea that this is a solid product.

If one is trying to sell a "revolutionary" new valvetrain, then don't BS the audience. Those that aren't familiar with car parts are not a likely population to go and buy a Coates system to put on the family minivan.

Whenever I hear about some brand new, amazing, blah blah blah, system, I want hard facts. This article seems to me like every infomercial I've ever seen. Specifically, it's a bunch of fuzzy statements that don't entirely make sense, even on face value.

Billege,

My thouights entirely, very frustrated that Coates can't write it up in any language other than dummed down yukspeakfull of BS, nor open up a bit and let a real 3rd party outfit test anything they do... because I suspect this is the culmination of 70 years of work on rotary (cyl head) valves, since Aspin and Cross treid so hard to get to grips with it... Definitely looks like it holds more promise than any of those... as for 14,000 rpm 5-litre V-8s, just why quote such a stupid example, when what we need to see are BMEP and SFC curves... surely they must know that, being engineers?

Possibly the answer lies in being extrenmely nervous about their development being 'knocked off' - esp. as the US has a history of copying and ignoring others' patents, right back to the early Ricardo years with Henry Ford. Perhaps they are also valuing their licenses a bit too highly, as to get a biggie to bite and take it further, one has to look at the long term game, and that is a very few % (to use Ricardo's patents used to be very cheap, about 2.5% or less IIRC)

But overall, there is something really strange about the way they are holding back... and controlling any reports and photos, drawings etc. No way to get this accepted IMHO - If it's good, and copyrighted, they have nothing to worry about, and it DOES look like the best rotary valve yet -except of course the simplest ones, the piston controlled port and the single sleeve valve :)

Think you'll find that opening out the ports 'slows' gas speed, this is bernoullis theorem, or even simpler than that, continuity. Agree its not alwasy a good idea though

I saw this a while ago, and it seems to be a viable solution to increasing flow in the valvetrain, and also, combined with a few other factors, potentially increasing an engine's operating RPM.

Things that Limit RPM, and their solutions:
Poppet Valve Float
Potential Solution: This

Piston Velocity breaking rods
Potential Solution: Forged rods, low stroke, high bore

Flame front propegation
Potential solution: Direct injection

Maxed out crank bearings
Potential solution: Better bearings..7000rpm is nowhere near the limit for industrial bearings (think turbojet engines and fans), get some better ones.

Anybody else got any? Drivetrain loss from gear friction through the transmission might start to get ridiculous above about 20k, we might need to strictly use belt drive or helical CVT's for at least the inital reduction.