Coates Spherical Rotary Valve Engine? December 17, 2007, 12:22:26 PM http://www.coatesengine.com/technology.htmlCan anyone tell me what's up with this engine?It sounds like a big improvement over valves/springs, but are their claims believable? Quote Selected
Coates Spherical Rotary Valve Engine? Reply #1 – December 17, 2007, 12:23:39 PM This has been around for ages. It's probably a repost as well.*edit*Yep. 20 seconds to search the word 'coates'.http://www.foxtbirdcougarforums.com/showthread.php?t=9122&highlight=coates Quote Selected
Coates Spherical Rotary Valve Engine? Reply #2 – December 17, 2007, 12:48:07 PM And your response about blowby was very interesting. Thanks for digging that up, I didn't even think about searching for it first. :) Quote Selected
Coates Spherical Rotary Valve Engine? Reply #3 – December 17, 2007, 02:20:46 PM Definitely a cool and fresh look at the ICE, but there must be some downside, if the system was developed that long ago and we've yet to see it in street production. I wouldn't expect Mazda or Honda to be on board, but you'd think at least the crazy French would scoop up the rights. Quote Selected
Coates Spherical Rotary Valve Engine? Reply #4 – December 17, 2007, 03:52:12 PM I heard of this years ago, searched for it lots on the net also (google) but couldent remember "Coates" I kept searching for "Gates" What I heard then was...1) GM bought thr rights to the design and shelved it to keep it from ever going into production. 2) The Oil has no need to enter the head, therefor never hitting the 1000+ degree temps that break it down.3) Oil not breaking down means WAY extended engine life4) extended engine life means no replacing engines and cars lasting longer.5) no body buying new GM's (<-- the reason for shelfing it) Like I said this is what I "Heard" and "remember" (and keep in mind I have short tearm loss of long tearm memory ...err Or was that Long tearm loss of short tearm memory.. hell I can't remember) from years ago.. So I'm going to read up on it now Quote Selected
Coates Spherical Rotary Valve Engine? Reply #5 – December 17, 2007, 04:17:46 PM Ok... what thread we continuing this in?As for the blowby issueQuote“In addition, the spherical rotary valve combustion engine utilizes a proprietary seal at the intake and exhaust ports of the cylinder to prevent pressure leakage. This two-piece seal contacts the peripheral surface of the rotary valve and utilizes the compression and expansion of the fuel and air mixture to create a gas-tight seal with the valves And on top of that, with Quote“Because the valves rotate away from the combustion chamber and are vented and charged on the opposite side of each sphere, this creates a lower combustion chamber temperature, allowing for higher compression ratios to be used thus creating an extremely efficient engine. Some of the Coates Spherical Rotary Combustion Engines are at 12 to 1, 13 to 1, 14 to 1 and 15 to 1 compression ratios depending on the application.[/FONT][/COLOR]15:1 Compression… who needs Boost Quote Selected
Coates Spherical Rotary Valve Engine? Reply #6 – December 17, 2007, 04:27:25 PM Several F1 teams tried this type of head back in the early 90's. didn't last long with any of them. In order to get enough air flow the sphere's had to be fairly large, with a large "open" relief cut. Made it difficult to properly balance the shaft and engines vibrated themselves to death or just didn't have the power. Quote Selected
Coates Spherical Rotary Valve Engine? Reply #7 – December 17, 2007, 09:02:16 PM I'm always interested in new ways to do old things, but I am highly skeptical of many of the claims made on that website. For example:QuoteLower Emissions - Conventional engines run hot due to their inability to disperse heat from the firing chamber. The resulting high temperatures break down the oil used to lubricate the valves and produce oxides of nitrogen as well as the usual hydrocarbons.Dispersing heat from an engine is done for parts longevity, not efficiency. They call the heat removed from the combustion chamber "Waste heat" for a reason - it's heat that the fuel generated that is not doing any work.QuoteIn addition, oil entering the combustion chamber through the intake valve is continually redirected back into the induction system due to pressure provided by the exhaust valve. This process compounds the problem of oil burning in a conventional engine.Umm... what?!?!?QuoteThe Coates engine avoids the problem of oil burning by requiring no oil lubricants for the valves. Moreover, the rotation of the spherical valve heads reduces engine temperature by constantly changing the surface exposed to combustion heat. By eliminating the use of oil in valve lubrication and lowering operating temperature, the Coates engine emits significantly lower levels of pollutants than a conventional engine.Most oil burning is caused by worn rings, not valve guides. Yes, I know, some engines are pr0ne to valve guide wear and smoking on start up (I'm looking at you, small-block Chevy and Saturn engines, among others), but by far most oil that ends up in the combustion chambers gets there via the oil rings, or via the PCV system when the compression rings are worn. The Coates engine does absolutely nothing to address this.QuoteReduced Fuel Requirements - Conventional engines lose power through friction and pumping. The spherical rotary valve assembly virtually eliminates engine friction and pumping losses. As a result of this operating efficiency, engines incorporating the spherical rotary valve design offer higher fuel economy than do conventional engines.Most of the friction in an engine is caused by the rings, more particularly, the oil rings, as they se the cylinder walls. The "pumping losses" in an engine are a factor of engine vacuum - as the piston goes down it works against a vacuum, causing pumping losses. Any "throttled" engine that has its intake air restricted by a throttle butterfly has high pumping losses. A diesel engine does not have such losses because its intake is open to the atmosphere, which contributes to its efficiency.The rotary valve system described in that website does absolutely nothing to "virtually eliminate" engine friction and pumping losses. Any friction lost through the elimination of a cam, lifters and valves (which can easily be almost eliminated by using roller gear) would likely be more than offset by the rotation of those rotary valves against their seals....and QuoteReduced Lubrication Requirements - The use of seals and shaft bearing make oil lubrication of the valve heads unnecessary and lower the overall oil requirements of the Coates engine in comparison to a conventional engine. Without the component wear that characterizes typical poppet valve systems, engines using the spherical rotary valve design also produce fewer metallic particulates. As a result of these factors, the spherical rotary valve engine can realize longer maintenance intervals than conventional engines.Most modern engines use roller cams. "Valve heads" do not require lubrication, and are in fact not lubricated at all in any engine designed to run on unleaded fuel (older engines used the lead in the fuel to lubricate the valve seats and heads). Since roller cams and hydraulic lifters have become mainstream wear in the valvetrain is very rare. Not mentioned in that website is the wear that would happen to the rotary valves and their seals, and to the bearings the rotary valve "camshaft" rides on.Most of the wear in oil comes from shearing forces as the oil is forced through crank bearings, and through contamination from ring blowby and condensation from running the engine cold. The Coates engine does nothing to reduce or eliminate any of this wear....and this:QuoteIncreased Engine Power - The comparative efficiencies of the spherical rotary valve combustion engine have enabled engine speeds of 14,850 RPMs. In addition, the spherical rotary valve design can accommodate markedly higher compression ratios than conventional engines. The rotary design provides these exceptionally higher compression ratios with no detectable detonation when utilizing fuels of lower octane ratings. These factors, coupled with the ability of the rotary valve head to deliver more fuel to the combustion chamber than the poppet valve, makes the Coates design especially well suited for more powerful engines.Anyone who has ever watched an F1 race knows that 14,850 RPM is nothing spectacular. Poppet-valve-based F1 engines spin to 18,000RPM and beyond. Production dog-fvcking-a-football motorcycle engines approach, if not surpass, 14,850 RPM with poppet valves.In other words, I think the reason that the Coates engine hasn't gone anywhere is that they make ridiculous claims with nothing to back them up. Meanwhile more promising engine technologies are either in production (BMW's Valvetronic) or just around the corner (HCCI). Call me a skeptic if you will, but unless I could see evidence of the claims made by Coates, even more elabourate explanations of how they came about making those claims, I don't buy it. Apparently, neither do the automakers. Quote Selected
Coates Spherical Rotary Valve Engine? Reply #8 – December 17, 2007, 09:45:47 PM I want one just so that I could guarantee that there'd never be a bad lifter or something that would make the valvetrain do the old yakkety-yak-yak :hick: Quote Selected
Coates Spherical Rotary Valve Engine? Reply #9 – December 18, 2007, 09:40:50 AM Thanks all, I used your thoughts to validate my opinions...always need expert opinions to justify yours...and then my editor threw it up for others to see here:http://www.thetruthaboutcars.com/news-blog/coates-spherical-rotary-valve-system-let-the-rivet-counting-begin/ Quote Selected
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