Ball Valves again
Discussion
Ball valves have popped up in a few threads in the Engine section. I'm a big fan of them. (see www.coatesengine.com if you've no idea of what I'm talking about)
I'm also interested in renewable energy and was messing about on the net cos I was bored out of my skull when I stumbled across this.
taken from www.shec-labs.com
[quote]
INSIDE TRACK
Valve Redesign = Engine Revolution
Following 15 years of research and development
on his patented spherical rotary valve engine, engineer
and entrepreneur George Coates recently began limited
commercial production of what could be the greatest
technological innovation in internal combustion since its invention.
The Coates Spherical Rotary Valve engine rids the
internal combustion engine of the poppet valve—
responsible for several key shortcomings, such as
overheating at high compression and low engine
efficiency. Coates’ innovation replaces poppet valves,
valve springs, guides, camshaft, pushrods, rocker arms
and other moving parts with two rotating spherical valve trains, enabling more efficient and stronger internal combustion and compression strokes.
The increased horsepower of CSRV engines
generate more kilowatts of electrical output per unit of gas than conventional engines, while their high thermal efficiency results in lower fuel consumption and emissions.
CSRV engines can be fit for nearly all applications
of the internal combustion engine and can operate on a
wide array of fuels. No oil is required in the upper engine, allowing for oil replacement at intervals of no less than 50,000 miles—most certainly bad news for Jiffy Lube et al. should the technology gain penetration into mass markets for vehicles.
In late spring, Coates International Ltd. began making
such inroads, signing licenses with McLean, England &
Associates for $25 million plus royalties to market the
Coates engine for use in four-ton vehicles across North
America. According to Coates, “CIL has received deposits on five more licenses in the United States at $25 million per license.” This includes all Porsche motorcar engines for the US market, as well as other road-racing, marine-racing, hotrodding and V8-retrofit applications. These agreements are still awaiting completion.
The technology will gain its first strong commercial
foothold through Calgary, Alberta-based Well to Wire
Energy, which CIL licensed to sell natural-gas generators and stand-alone power systems. Well to Wire has booked 540 projects to turn waste gas of all kinds into electricity across the United States and Canada with technology based on a 300-KW Coates engine. Full
production of these engines is scheduled for the first
quarter of 2003.
This summer, Well to Wire Chief Executive Officer
Neil Munro met with Portland General Electric’s director of distributed generation, Joe Barra, who told Prospects that the Coates engine does appear to be a very significant advance. Barra is eager to demonstrate the innovation at such sites as wastewater treatment plants, landfills and electricity-generating facilities at swine and dairy farms, and is negotiating with Well to Wire to begin such testing.
Of particular interest to Barra is the reliability of the rotary valve seals, as biogas contains trace elements that deteriorate valve seals and other parts of conventional reciprocating engines, making operation and maintenance expensive. According to Munro, the Coates engine can reduce operating and maintenance costs by 50 to 60 percent compared to conventional engines.
Currently, Coates International awaits the results of
US Environmental Protection Agency emissions testing
of CSRV engines. According to tests conducted by CIL,
Coates engines reduce hydrocarbon emissions by 66 percent over standard reciprocating engines, carbon
dioxide emissions by 32 percent and nitrogen oxides by
97 percent. [G.H.]
More information:
Coates International Ltd. (www.coatesengine.com)
Well to Wire Energy (www.welltowire.com)
Portland General Electric (www.portlandgeneral.com)
[/quote]
The important word in that article is Porsche.
When Coates Engineering tested a 5 litre V8 with these valves they managed to get something like 450hp at 5500rpm. This is pretty impressive for this rpm. Imagine what it would be like fitted to a Porsche flat 6 with variable intakes etc.
Definentley one to keep an eye on.
I'm also interested in renewable energy and was messing about on the net cos I was bored out of my skull when I stumbled across this.
taken from www.shec-labs.com
[quote]
INSIDE TRACK
Valve Redesign = Engine Revolution
Following 15 years of research and development
on his patented spherical rotary valve engine, engineer
and entrepreneur George Coates recently began limited
commercial production of what could be the greatest
technological innovation in internal combustion since its invention.
The Coates Spherical Rotary Valve engine rids the
internal combustion engine of the poppet valve—
responsible for several key shortcomings, such as
overheating at high compression and low engine
efficiency. Coates’ innovation replaces poppet valves,
valve springs, guides, camshaft, pushrods, rocker arms
and other moving parts with two rotating spherical valve trains, enabling more efficient and stronger internal combustion and compression strokes.
The increased horsepower of CSRV engines
generate more kilowatts of electrical output per unit of gas than conventional engines, while their high thermal efficiency results in lower fuel consumption and emissions.
CSRV engines can be fit for nearly all applications
of the internal combustion engine and can operate on a
wide array of fuels. No oil is required in the upper engine, allowing for oil replacement at intervals of no less than 50,000 miles—most certainly bad news for Jiffy Lube et al. should the technology gain penetration into mass markets for vehicles.
In late spring, Coates International Ltd. began making
such inroads, signing licenses with McLean, England &
Associates for $25 million plus royalties to market the
Coates engine for use in four-ton vehicles across North
America. According to Coates, “CIL has received deposits on five more licenses in the United States at $25 million per license.” This includes all Porsche motorcar engines for the US market, as well as other road-racing, marine-racing, hotrodding and V8-retrofit applications. These agreements are still awaiting completion.
The technology will gain its first strong commercial
foothold through Calgary, Alberta-based Well to Wire
Energy, which CIL licensed to sell natural-gas generators and stand-alone power systems. Well to Wire has booked 540 projects to turn waste gas of all kinds into electricity across the United States and Canada with technology based on a 300-KW Coates engine. Full
production of these engines is scheduled for the first
quarter of 2003.
This summer, Well to Wire Chief Executive Officer
Neil Munro met with Portland General Electric’s director of distributed generation, Joe Barra, who told Prospects that the Coates engine does appear to be a very significant advance. Barra is eager to demonstrate the innovation at such sites as wastewater treatment plants, landfills and electricity-generating facilities at swine and dairy farms, and is negotiating with Well to Wire to begin such testing.
Of particular interest to Barra is the reliability of the rotary valve seals, as biogas contains trace elements that deteriorate valve seals and other parts of conventional reciprocating engines, making operation and maintenance expensive. According to Munro, the Coates engine can reduce operating and maintenance costs by 50 to 60 percent compared to conventional engines.
Currently, Coates International awaits the results of
US Environmental Protection Agency emissions testing
of CSRV engines. According to tests conducted by CIL,
Coates engines reduce hydrocarbon emissions by 66 percent over standard reciprocating engines, carbon
dioxide emissions by 32 percent and nitrogen oxides by
97 percent. [G.H.]
More information:
Coates International Ltd. (www.coatesengine.com)
Well to Wire Energy (www.welltowire.com)
Portland General Electric (www.portlandgeneral.com)
[/quote]
The important word in that article is Porsche.
When Coates Engineering tested a 5 litre V8 with these valves they managed to get something like 450hp at 5500rpm. This is pretty impressive for this rpm. Imagine what it would be like fitted to a Porsche flat 6 with variable intakes etc.
Definentley one to keep an eye on.
Interesting site, but after wading through the “Coates Spherical Rotary Valve Engine is the most advanced in the world” sales bollocks I found a few points to argue with…
Do the seals last? It took Mazda decades to get the seals to last on rotary engines (assuming the RX8 doesn’t spit them out after 60000 miles… anyone want a bet?) They don’t mention durability anywhere.
“...the rotation of the spherical valve heads reduces engine temperature by constantly changing the surface exposed to combustion heat.” My arse. The heat doesn’t just vanish – it’ll be conducted through to increase cylinder head temperatures. Poppet valves get nice and toasty but don’t pass as much heat through to the head as the ball valve would. Hmm, lower initial exhaust temperatures to extend cat light off times – that’ll hurt emissions compliance.
“The spherical rotary valve assembly virtually eliminates engine friction” Reduces valve train friction certainly (ignoring the potential for huge drag from the seals), but lets not get silly eh?
“comparative efficiencies of the spherical rotary valve combustion engine have enabled engine speeds of 14,850 RPMs” Oh dear. I thought it was mean piston speed which dictated the max rpm for a given engine layout. Poppet valves are already happily in service for engines that rev to 22,000rpm and have been for decades.
“The average poppet valve opens a maximum of approximately 8 millimeters, restricting air flow. In addition, valves in high compression engines cannot open before top dead center. If they do, they will make contact with the piston and engine destruction occurs” Certainly you could design a poppet valve engine to be as bad as they claim, if you were trying. What they need to do to win us over it to compare cutting edge poppet valve engines with the ball valve version of the same engine (Honda S2000 or BMW M3, not huge old Yank V8s) – anything else is just sales bullshit, not engineering.
Still, I'm all for diversity - good luck to them.
Do the seals last? It took Mazda decades to get the seals to last on rotary engines (assuming the RX8 doesn’t spit them out after 60000 miles… anyone want a bet?) They don’t mention durability anywhere.
“...the rotation of the spherical valve heads reduces engine temperature by constantly changing the surface exposed to combustion heat.” My arse. The heat doesn’t just vanish – it’ll be conducted through to increase cylinder head temperatures. Poppet valves get nice and toasty but don’t pass as much heat through to the head as the ball valve would. Hmm, lower initial exhaust temperatures to extend cat light off times – that’ll hurt emissions compliance.
“The spherical rotary valve assembly virtually eliminates engine friction” Reduces valve train friction certainly (ignoring the potential for huge drag from the seals), but lets not get silly eh?
“comparative efficiencies of the spherical rotary valve combustion engine have enabled engine speeds of 14,850 RPMs” Oh dear. I thought it was mean piston speed which dictated the max rpm for a given engine layout. Poppet valves are already happily in service for engines that rev to 22,000rpm and have been for decades.
“The average poppet valve opens a maximum of approximately 8 millimeters, restricting air flow. In addition, valves in high compression engines cannot open before top dead center. If they do, they will make contact with the piston and engine destruction occurs” Certainly you could design a poppet valve engine to be as bad as they claim, if you were trying. What they need to do to win us over it to compare cutting edge poppet valve engines with the ball valve version of the same engine (Honda S2000 or BMW M3, not huge old Yank V8s) – anything else is just sales bullshit, not engineering.
Still, I'm all for diversity - good luck to them.
You know, Captain, this reminds me of a thread a while back about magnetic fuel filters or some such. I said I was a little sceptical that they could do what was claimed, but I was shot down in flames by several folk. However, I haven't noticed that the general motoring population (or even dedicated petrolheads such as those who frequent this site) have rushed out in droves to buy them.
I suspect the average engine maker will not be queueing up for ball valve technology...
(Sorry, Andy! 
)
I suspect the average engine maker will not be queueing up for ball valve technology...
(Sorry, Andy! ) 
geee, it'd be nice if I gave you the link to go along with the comments i have on it. here you go:
www.automotivehelper.com/topic11278.htm
www.automotivehelper.com/topic11278.htm
Captain Muppet said:
Interesting site, but after wading through the “Coates Spherical Rotary Valve Engine is the most advanced in the world” sales bollocks I found a few points to argue with…
Do the seals last? It took Mazda decades to get the seals to last on rotary engines (assuming the RX8 doesn’t spit them out after 60000 miles… anyone want a bet?) They don’t mention durability anywhere.
IIRC, the apex-seal problems that Mazda (and NSU before them) had was due to the impact the seals had to withstand when the rotors slammed up against the housing. The right alloy put that problem to bed back in the 1970s - hence the introduction of the RX-7 in the late 70s.
After more than 20 years of fine-tuning, you don't want to bet against Mazda's apex seals. With proper care, a Wankel will see 200,000 miles and more. Once rebuilt, they can be trick though because a lot of the people who do it, don't know how to do it properly.
Captain Muppet said:
“...the rotation of the spherical valve heads reduces engine temperature by constantly changing the surface exposed to combustion heat.” My arse. The heat doesn’t just vanish – it’ll be conducted through to increase cylinder head temperatures. Poppet valves get nice and toasty but don’t pass as much heat through to the head as the ball valve would. Hmm, lower initial exhaust temperatures to extend cat light off times – that’ll hurt emissions compliance.
That could be a big problem. Still, maybe a "preheating" system for the cats would solve it.
Captain Muppet said:
“The spherical rotary valve assembly virtually eliminates engine friction” Reduces valve train friction certainly (ignoring the potential for huge drag from the seals), but lets not get silly eh?
“comparative efficiencies of the spherical rotary valve combustion engine have enabled engine speeds of 14,850 RPMs” Oh dear. I thought it was mean piston speed which dictated the max rpm for a given engine layout. Poppet valves are already happily in service for engines that rev to 22,000rpm and have been for decades.
Yeah, and so are the con-rods that allow such speeds. But they're both VERY expensive.
In reality, the Coats people are talking about pushrod engines and I think you'll find that the valve-train on such an engine is the main limiting factor when it comes to revving high.
I used to know an engineer who claimed to have designed a rotary valve system for a pushrod Chevy V-8. He said it gave him significantly more power and several thousand more revs headroom on the engine. I didn't get a chance to see it alas, but he was a pretty sharp guy and I believed him.
Put another way... sure F1 engines can rev past 20,000... that isn't too impressive anymore. But wouldn't a small-block Chevy engine that can rev to 14,000rpm be worth having?
Captain Muppet said:
“The average poppet valve opens a maximum of approximately 8 millimeters, restricting air flow. In addition, valves in high compression engines cannot open before top dead center. If they do, they will make contact with the piston and engine destruction occurs” Certainly you could design a poppet valve engine to be as bad as they claim, if you were trying. What they need to do to win us over it to compare cutting edge poppet valve engines with the ball valve version of the same engine (Honda S2000 or BMW M3, not huge old Yank V8s) – anything else is just sales bullshit, not engineering.
I beg to differ. What they're offering is the performance advantage of a high-end DOHC system with the compact package of a pushrod engine. That's more than just sales bullshit.
Plus, even on the most efficient DOHC system, you're still giving up engine power to compress the springs in the valvetrain that could just as well be used to turn the car's wheels.
Never use a reciprocating part when you can use a rotating part instead.
Jon Gwynne said:
Never use a reciprocating part when you can use a rotating part instead.
Damn straight, this is the crux of it.
This and the reduced parts count is what I see as the big advantages.
And if Porsche are interested then it must be worth something, as companies like that don't perk up interest unless they smell a competitve advantage or a competitor they can buy out.
Andy
andytk said:
Never use a reciprocating part when you can use a rotating part instead.
Damn straight, this is the crux of it.
This and the reduced parts count is what I see as the big advantages.
And if Porsche are interested then it must be worth something, as companies like that don't perk up interest unless they smell a competitve advantage or a competitor they can buy out.
Andy
Is Porsche interested? I always figured TVR would be the one to bring this thing into reality if it were possible to do so. They make their own engines and they're iconoclastic enough to say "screw what everyone else is going, we're going to do it the way WE think is best".
Anyone know how must power the Speed Six's valvetrain subtracts from the output? It must be in the region of 50-75bhp? Imagine getting that kind of boost to that engine's power without having to put any additional stress on any of the engine's components...
I seem to remember (the late) CCC mag doing an article on a rover V8 which had been gived one of these valve systems. It must have been at least 10 years ago. It said something along the lines of 'very very impressive, but how long is it's life-span' they then mentioned that they would keep an eye on it, but I don't remember any follow up to it. I may be having a premature senior moment!
Jon Gwynne said:
After more than 20 years of fine-tuning, you don't want to bet against Mazda's apex seals. With proper care, a Wankel will see 200,000 miles and more. Once rebuilt, they can be trick though because a lot of the people who do it, don't know how to do it properly.
Sorry, I must lurk on the RX7 forums where people lie about low compression due to tip wear after 60000 miles as justification for getting their engine rebuilt for the shear joy of spending money.
If tip seals didn't wear out there wouldn't be anyone rebuilding them wrong would there?
Jon Gwynne said:
That could be a big problem. Still, maybe a "preheating" system for the cats would solve it.
Yes, there are electrically heated cats. Yes, they are huge. Yes, it is a inelegant engineering solution. (heavy and expensive too)
Jon Gwynne said:
Yeah, and so are the con-rods that allow such speeds. But they're both VERY expensive.
No, they aren't. Getting parts from aftermarket suppliers might well be expensive, but designing in high rev capability for production engines is relativley inexpensive.
Jon Gwynne said:
In reality, the Coats people are talking about pushrod engines and I think you'll find that the valve-train on such an engine is the main limiting factor when it comes to revving high.
I used to know an engineer who claimed to have designed a rotary valve system for a pushrod Chevy V-8. He said it gave him significantly more power and several thousand more revs headroom on the engine. I didn't get a chance to see it alas, but he was a pretty sharp guy and I believed him.
Put another way... sure F1 engines can rev past 20,000... that isn't too impressive anymore. But wouldn't a small-block Chevy engine that can rev to 14,000rpm be worth having?
Dear God. Pushrod technology is shite. It's a peice of piss to improve on. Sown me a ball valve that improve on a modern poppet valve system (Honda S2000, BMW M3, any bike engine) and I'll be impressed.
As for this engineer you knew - Engineers are ten a penny, hell I'm an engineer. Yes, we can all improve on someone else's shite design. Improvong on a good design is the tricky bit.
Jon Gwynne said:
I beg to differ. What they're offering is the performance advantage of a high-end DOHC system with the compact package of a pushrod engine. That's more than just sales bullshit.
OK, differ. When they convert a cutting edge DOHC engine to ball valves and shrink the package (to create the extra 70mm pedestrian impact clearance that all the designers are looking for) then I'll be impressed. If they are really offering the space saving you think they are then ball valve engines will be in production in five years.
Jon Gwynne said:
Plus, even on the most efficient DOHC system, you're still giving up engine power to compress the springs in the valvetrain that could just as well be used to turn the car's wheels.
Those springs decompess as well
Jon Gwynne said:
Never use a reciprocating part when you can use a rotating part instead.
Absolutely, unless the rotating part won't do the job. Engine manufacturers aren't stupid. They are driven by cost, efficiency, ease of manufacturing, packaging and customer power targets. If ball valves beat poppet valves in those five areas they will make it into production. At the moment they don't.
>> Edited by Captain Muppet on Sunday 7th March 01:50
Captain Muppet said:
Absolutely, unless the rotating part won't do the job. Engine manufacturers aren't stupid. They are driven by cost, efficiency, ease of manufacturing, packaging and customer power targets. If ball valves beat poppet valves in those five areas they will make it into production. At the moment they don't.
Engine manufacturers are also constrained by what technology they own. Why do you think different manufacturers spend vast sums of money designing slightly different variations on what is essentially the same theme ie. variable valve timing 4 valve + heads. Which, lets face it, Honda had licked ages ago.
Most car companies can only use what rights they own, the alternative is to lease or buy rights which is expensive. Few will do it if they can develop their own.
THIS is the reason that current engine makers still persist with poppet valves. Also there is the cost of tooling up a new type of production.
Captain Muppet said:
Those springs decompess as well
Yes but that deosn't mean you'll get the energy back. It doesn't work like that. Call yourself an engineer....:wink:
Captain Muppet said:
Dear God. Pushrod technology is shite. It's a peice of piss to improve on. Sown me a ball valve that improve on a modern poppet valve system (Honda S2000, BMW M3, any bike engine) and I'll be impressed.
As for this engineer you knew - Engineers are ten a penny, hell I'm an engineer. Yes, we can all improve on someone else's shite design. Improvong on a good design is the tricky bit.
I still think they have. You're not looking at the stats properly.
Take what they say about the ford clucker conversion.
475 lbft torque and 475 hp AT 5350 rpm.
That last bit is the important bit. You show me a quad valve engine that can do that. Really. Try. Its not easy.
All these quad poppert valve engines develop their power by revving. hell the S2000 has its peak torque at 7200rpm. THATS how it develops its power. I'm willing to bet that it doesn't deliver 95 hp/litre at 5350 rpm. Not many and certainly not the S2000.
Now consider if the above engine could hold 80% of its torque till, say, 7500rpm. Shouldn't be a problem if the breathing is as good as they say it is.
Lets see now. That would be 380lbft torque. Which at 7500 rpm is about 530hp. Thats well over 100bhp/litre.
Not so bad now. And without all the complexity of poppet valves.
By the way the reason that Coates probably quoted the torque and hp at that engine speed is cos the power and torque are roughly the same at about 5350 rpm.
Captain Muppet said:
OK, differ. When they convert a cutting edge DOHC engine to ball valves and shrink the package (to create the extra 70mm pedestrian impact clearance that all the designers are looking for) then I'll be impressed. If they are really offering the space saving you think they are then ball valve engines will be in production in five years.
Its not really about shrinking the engine package, its really about simplifying what is a very complex and flawed system. After all wouldn't you want to reduce the parts count in in such a critical area. Plus I still don't trust all those little reciproating parts. Plus they tend to get very hot at the tips thus causing problems. Best elimenated.
I tend to think you're picking holes for the sake of it rather than with valid reasons.
Plus you've missed the biggest trick that ball valves have up their sleeves anyway.
Just think Diesel.....
Andy
>> Edited by andytk on Wednesday 10th March 20:38
andytk said:
Engine manufacturers are also constrained by what technology they own...
...THIS is the reason that current engine makers still persist with poppet valves. Also there is the cost of tooling up a new type of production.
The Tier 1 suppliers tend to own the patents (and do most of the research) and the tooling cost is almost always absorbed by the suppliers too. Honda have a culture of producing their own technology, but most manufacturers trust the suppliers to keep up with the latest developments as the suppliers have much more experience. A manufacturer will throw together a new engine every six to ten years, a supplier is doing it all the time.
Most manufacturers will jump at the chance to have cheaper, better engines, especially as the assembly line is one of the major costs of a new engine and ball valve engines will be cheaper to assemble.
andytk said:
Yes but that deosn't mean you'll get the energy back. It doesn't work like that. Call yourself an engineer....:wink:
You get most of the engergy back - hysterisis losses in spring steel are low.
andytk said:
I still think they have. You're not looking at the stats properly.
Take what they say about the ford clucker conversion.
475 lbft torque and 475 hp AT 5350 rpm.
That last bit is the important bit. You show me a quad valve engine that can do that. Really. Try. Its not easy.
All these quad poppert valve engines develop their power by revving. hell the S2000 has its peak torque at 7200rpm. THATS how it develops its power. I'm willing to bet that it doesn't deliver 95 hp/litre at 5350 rpm. Not many and certainly not the S2000.
Now consider if the above engine could hold 80% of its torque till, say, 7500rpm. Shouldn't be a problem if the breathing is as good as they say it is.
Lets see now. That would be 380lbft torque. Which at 7500 rpm is about 530hp. Thats well over 100bhp/litre.
Not so bad now. And without all the complexity of poppet valves.
By the way the reason that Coates probably quoted the torque and hp at that engine speed is cos the power and torque are roughly the same at about 5350 rpm.
The rpm that peak torque is developed at depends on a lot more than the valve train. Bore:stroke ratio for a start and tunned lengths in the inlet and exhaust.
My point was that if they converted an engine that was fitted with an adequate valvetrain (pick a low reving BMW V8 if you like) rather than a clonky pushrod pile of poo it would be a much better demonstration of the system, and it would shut me up.
andytk said:
Its not really about shrinking the engine package, its really about simplifying what is a very complex and flawed system. After all wouldn't you want to reduce the parts count in in such a critical area. Plus I still don't trust all those little reciproating parts. Plus they tend to get very hot at the tips thus causing problems. Best elimenated.
Shrinking the engine package is a big issue right now - this is a potentially huge selling point of a ball valve engine, yet still they are being ignored. Possible because no one trusts all those big rotating parts
andytk said:Hell yes
I tend to think you're picking holes for the sake of it rather than with valid reasons.
I've had the same argument before (here and on other less enlightened forums) so I tend to get a bit spiky about it. For a couple of years I worked as a project engineer on an engine that's currently in production, so I tend to see things a little differently.
andytk said:Think huge cylinder pressures and those delicate seals. It would make one hell of an impressive demonstrator if they did it though.
Plus you've missed the biggest trick that ball valves have up their sleeves anyway.
Just think Diesel.....
I'm half hoping Coates see this and build a more relevant demonstrator. I'm all for new technology, if it works. Coates aren't marketing this very well.
Captain Muppet said:
Sorry, I must lurk on the RX7 forums where people lie about low compression due to tip wear after 60000 miles as justification for getting their engine rebuilt for the shear joy of spending money.
If tip seals didn't wear out there wouldn't be anyone rebuilding them wrong would there?
Speaking not only as someone who has owned two different Mazda RX-7s, both of which made it well past 100,000 miles on the original apex seals but also as someone who has known many other people who can claim the same, I'll just disagree.
I will give you one point though and that is that my days of RX-7 ownership were in California, not the UK. There is a nasty rumor going around that the additives in UK petrol eat wankel seals for lunch. I don't know if it is true, but a lot of the complaints I've heard about RX-7 engine longevity do seem to come from the UK...
>> Edited by Jon Gwynne on Monday 15th March 01:50
Captain Muppet said:
andytk said:
Yes but that deosn't mean you'll get the energy back. It doesn't work like that. Call yourself an engineer....:wink:
You get most of the engergy back - hysterisis losses in spring steel are low.
Its not the hysterisis, its the losses when the springs try to transfer the energy back through the cam. On the Coates website they listed the power requirements needed to drive a standard poppet valve train versus the ball valve. Now granted they probably went looking for the worst poppet system they could find for comparison purposes but even still the difference was huge.
Captain Muppet said:
The rpm that peak torque is developed at depends on a lot more than the valve train. Bore:stroke ratio for a start and tunned lengths in the inlet and exhaust.
My point was that if they converted an engine that was fitted with an adequate valvetrain (pick a low reving BMW V8 if you like) rather than a clonky pushrod pile of poo it would be a much better demonstration of the system, and it would shut me up.
I'll go find the stats.
Captain Muppet said:
Plus you've missed the biggest trick that ball valves have up their sleeves anyway.
Just think Diesel.....
Think huge cylinder pressures and those delicate seals. It would make one hell of an impressive demonstrator if they did it though.
Sigh. They have. Its their main product line.
I don't think you even looked at their website.
Andy
>> Edited by andytk on Monday 22 March 18:40
Well after inviting a representative from Coates to enlighten us on their products, I received the following response:
Dear Mr. Jenkins:
As applied to most people who comment on technology of which they do not have a full comprehension or understanding of the scientific attributes of the specific components, regarding spheres, ports, floating seals, volumetric efficiencies, valve timing, thermal efficiencies, compression ratios, acceleration curves, sequential fuel injection,
stoichiometric mixtures through the acceleration curve and co-efficiencies of the components
and the thermal efficiencies of an engine, etc, etc., is not something that can be explained in a short note of response. People that comment do not fully understand the scientific design characteristics of the CSRV, and, as it is well known, a small amount of knowledge is a dangerous thing, 99.9% of the general comments about the CSRV are absolutely wrong and we understand this as they are made in total ignorance of the science incorporated in the design of the CSRV.
Kindest regards,
Sincerely,
Sharon Dunn/Communications Manager
Oh thanks for that then Sharon, most helpful
Dear Mr. Jenkins:
As applied to most people who comment on technology of which they do not have a full comprehension or understanding of the scientific attributes of the specific components, regarding spheres, ports, floating seals, volumetric efficiencies, valve timing, thermal efficiencies, compression ratios, acceleration curves, sequential fuel injection,
stoichiometric mixtures through the acceleration curve and co-efficiencies of the components
and the thermal efficiencies of an engine, etc, etc., is not something that can be explained in a short note of response. People that comment do not fully understand the scientific design characteristics of the CSRV, and, as it is well known, a small amount of knowledge is a dangerous thing, 99.9% of the general comments about the CSRV are absolutely wrong and we understand this as they are made in total ignorance of the science incorporated in the design of the CSRV.
Kindest regards,
Sincerely,
Sharon Dunn/Communications Manager
Oh thanks for that then Sharon, most helpful
andytk said:
Its not the hysterisis, its the losses when the springs try to transfer the energy back through the cam. On the Coates website they listed the power requirements needed to drive a standard poppet valve train versus the ball valve. Now granted they probably went looking for the worst poppet system they could find for comparison purposes but even still the difference was huge.
rational reply pending data for decently engineered poppet valve losses...
Which may well not back me up
andytk said:
Sigh. They have. Its their main product line.
I don't think you even looked at their website.
I did look at the site, but four months ago. :eatshumblepie: OK - I'm impressed with the diesel.
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