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[QUOTE=stian1979]That depends on the gas my frien and I man enough to admit I'm wrong. Oxygen has a coefficient of (thermal) expansion at 4,86, but air has only 3,67 x 10^-3 K^-1[/QUOTE]
Wow you are a very confused person if I have 1 cubic centimeter of any gas and double the temperature then the gas will now fill 2 cubic centimeters! (think about it!) ((note that it is only a doubling of the absolute temperature that this happens))
[QUOTE=stian1979]This is a fact with modifications. How manny times the water will exspand depends on preshure and temperature. If the preshure is 22090kPa the water would not exspand at all and if it's at 1kPa it will exspand 120000 times.[/QUOTE]umm you do realise that I am talking about when water (a liquid) turns into dry steam (a gas) I assure you that water does turn to steam when injected into an engine and that the calculated value of expansion between water at it's densist (4deg C) and totally dry steam (100deg C) is over 1600 times. If you increase the temperature of the gas even more than it expands accordingly! ((in a confined container pressure goes up))
[QUOTE=stian1979]I don't belive you unless it's not a revetec annymore. Please make me [/QUOTE] My design is based on revetec insomuch as it still uses a counter-rotating cam system to convert linier motion into rotary motion. And I would rather you didn't believe in my design as that intolls faith and I have no need of faith!
[QUOTE=stian1979]I will not bet you on that, but there are diesels running on asfalt.
Large stroke ship's like you mention yourself befour. [/QUOTE]
Do you read my posts or what?!? I know that large ships run on warmed asphalt and other heavy oils they do so because it is super cheap! You will never have a car that runs on asphalt and therefore you previous statement is irrelevant!
[QUOTE=stian1979]and the revetec don't?
Giwe me your e-mail so I can write you a long lether for apology the day I buy my first revetec powered car.[/QUOTE]
the revetec system is relatively light weight and is much lower friction than a conventional crank design and the convensional crank design is much better than the yoke so...!
and I am not about to hand out my email to some yaahoo on a net forum cause all that will get me is a pathetic attemp to spam me!
[QUOTE=stian1979]Actualy I think it more from the the 1890-1910 area.[/QUOTE]EXACTLY do you realise that the normal crankshaft design that is in most ICEs right now was invented to replace the Yoke! the scotch yoke was dated back in 1910!
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[QUOTE=hightower99]Wow you are a very confused person if I have 1 cubic centimeter of any gas and double the temperature then the gas will now fill 2 cubic centimeters! (think about it!) ((note that it is only a doubling of the absolute temperature that this happens))[/QUOTE]
OK! so you don't belive in coefficient of (thermal) expansion? so nice, in your world a steel pipe wont grow longer if heated.
[QUOTE=hightower99]umm you do realise that I am talking about when water (a liquid) turns into dry steam (a gas) I assure you that water does turn to steam when injected into an engine and that the calculated value of expansion between water at it's densist (4deg C) and totally dry steam (100deg C) is over 1600 times. If you increase the temperature of the gas even more than it expands accordingly! ((in a confined container pressure goes up))[/QUOTE]
Now your talking about a preshure betwen 100-110kPa. My cylinder preshure is way higher than that. 100kPa is normal atmospheric pressure. This means that at a preshure of 18bara you will only get 92 times ekspension and this is only a compresion preshure. How high will it go durning combustuon? The ekspansion you are talking about will only hapend when the exhaust valve open.
[QUOTE=hightower99]My design is based on revetec insomuch as it still uses a counter-rotating cam system to convert linier motion into rotary motion. And I would rather you didn't believe in my design as that intolls faith and I have no need of faith![/QUOTE]
I recond this means no profe.
[QUOTE=hightower99]Do you read my posts or what?!? I know that large ships run on warmed asphalt and other heavy oils they do so because it is super cheap! You will never have a car that runs on asphalt and therefore you previous statement is irrelevant![/QUOTE]
I read your post twice as good as you read mine. I staded that diesels are the future because it can burn annything as long as it is a liquid and has calorific value.
[QUOTE=hightower99]the revetec system is relatively light weight and is much lower friction than a conventional crank design and the convensional crank design is much better than the yoke so...![/QUOTE]
I simply don't belive it has lover friction because off it's contrarotating mecanism. The ball bearing's is something that will nead replacement often and plain bearings can't be adopted.
[QUOTE=hightower99]and I am not about to hand out my email to some yaahoo on a net forum cause all that will get me is a pathetic attemp to spam me![/QUOTE]
On yourown actions you know others. Now I know what you would do.
[QUOTE=hightower99]EXACTLY do you realise that the normal crankshaft design that is in most ICEs right now was invented to replace the Yoke! the scotch yoke was dated back in 1910![/QUOTE]
So the normal crankshaft was invented after the Yoke? at 1910?
WOW. I have seen normal crankshaft engines fom 1906 in the Wickmann museum. Well at least you make me laugh.
The advantages compared to a standard crankshaft and connecting rod setup are:
High torque output with a small cylinder size.
Fewer moving parts.
Smoother operation.
Higher percentage of the time spent at top-dead-center and bottom-dead-center (dwell) improving engine efficiency.
The disadvantages are:
Rapid wear of the slot in the yoke.
This setup is most commonly used in control valve actuators in high pressure oil and gas pipelines.
See the Yoke is in sucsesful use [url]http://www.scana.no/no/ssr/news-and-media/nedlasting[/url]
Don't you even find it alarming that revetec hide so mutch information on there web page? If they have the patents nobody can steal it from them annyway.
I got a nice bock for you ISBN-82-00-42450-2 maybe they have it in English to.
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[Quote=stain1979]Don't you even find it alarming that revetec hide so mutch information on there web page? If they have the patents nobody can steal it from them annyway.[/Quote]
Just because you have a patent to protect your idea doesnt't mean you have any protection if you don't have the money to fight it in court.
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[QUOTE]OK! so you don't belive in coefficient of (thermal) expansion? so nice, in your world a steel pipe wont grow longer if heated.[/QUOTE]
Yes I do believe in coefficient of expansion (READ the post don't skim it!). Metals do expand when there temperature is raised but they do not follow the same rules as gasses (as in a rod of steel doesn't double it's volume if I double the absolute temperature) so gasses change there size, liquids change there size, and even solids change there size!
[QUOTE]Now your talking about a preshure betwen 100-110kPa. My cylinder preshure is way higher than that. 100kPa is normal atmospheric pressure. This means that at a preshure of 18bara you will only get 92 times ekspension and this is only a compresion preshure. How high will it go durning combustuon? The ekspansion you are talking about will only hapend when the exhaust valve open.[/QUOTE] sorry my last post (the part you quoted) has all the info there.
[QUOTE]I recond this means no profe.[/QUOTE]
No it means I don't need your faith! and what do you mean no proof I have only drawn some drawings and done some very like math. I have not got my hands on a revetec engine yet so I couldn't give you a direct proof but I could give you some pictures... and let you make your own conclusions.
[QUOTE]I read your post twice as good as you read mine. I staded that diesels are the future because it can burn annything as long as it is a liquid and has calorific value.[/QUOTE] Well just if it was alittle to unclear for you DEISELS ARE NOT AND WILL NOT BECOME SUPER POPULAR DUE TO THE FACT THAT THEY CAN BURN ALMOST ANYTHING THAT CAN BE ATOMISED AND HAS A CALORIC VALUE!!!!! the reasons for there increasing popularity has nothing to do with that it has to do with the things I stated. So next time READ my posts!
[QUOTE]I simply don't belive it has lover friction because off it's contrarotating mecanism. The ball bearing's is something that will nead replacement often and plain bearings can't be adopted.[/QUOTE] Counter rotating= less vibration= less loss due to frictions and stresses! and ball bearings can last along time if they are correctly matched to the job (Like in the ball bearing turbos I see which have been used hard for 120000km!!!)
[QUOTE]So the normal crankshaft was invented after the Yoke? at 1910?
WOW. I have seen normal crankshaft engines fom 1906 in the Wickmann museum. Well at least you make me laugh.
The advantages compared to a standard crankshaft and connecting rod setup are:
High torque output with a small cylinder size.
Fewer moving parts.
Smoother operation.
Higher percentage of the time spent at top-dead-center and bottom-dead-center (dwell) improving engine efficiency.
The disadvantages are:
Rapid wear of the slot in the yoke.[/QUOTE] Yes the scotch yoke came first or very very close to the crankshaft. The normal crankshaft wasn't invented in 1910 and I never said it was! I said that the scotch yoke was old tech by 1910!
the advantages you list are rediculess and they are not true
The crankshaft/connecting rod design gets better torque per [B]smaller cylinder size[/B] (What ever that means?)
A scoth yoke needs 4 parts for a single piston while a normal setup needs only 3. So a normal setup has fewer parts.
smoother operation might be true due to less side loading.
And the last bit about more time at TDC and BDC is really funny cause that will not help an engine much especially in the future when they need to run on detonation mode! (You do know that a piston does no work at TDC and BDC so why should it be there for a longer amount of time?) Your listed disadvantage is only the most obvious one which is caused by a large amount of friction! it is most definately true!
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[quote=stian1979]Don't you even find it alarming that revetec hide so mutch information on there web page? If they have the patents nobody can steal it from them annyway.[/quote]
If you ever manage to invent then do NOT make that mistake.
Every patent application is kep as secret as possible until it is made public.
This can be up to two years and in some cases is deliberately made longer by the patentee by adding additional claims.
BECAUSE ....... as soon as your patent goes public there are companies who will take that patent and work to identify uses not considered AND possible developmetn needs in teh future. These companies then VERY QUICKLY apply for patents for those features. Suddenly a patent holder fo the KEY design finds out that he can't actually develop the product because of these other patents and has to engage in trying to purchase those rights.
Patents which were intially set up to ensure sharing of techincal advances has now become a business in it's own right.
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[QUOTE=hightower99]Yes I do believe in coefficient of expansion (READ the post don't skim it!). Metals do expand when there temperature is raised but they do not follow the same rules as gasses (as in a rod of steel doesn't double it's volume if I double the absolute temperature) so gasses change there size, liquids change there size, and even solids change there size![/QUOTE]
So you realised that now?
Iron 11,7 x 10^-6 K^-1 (coefficient of expansion in lenght)
water 0,21 x 10^-3 K^-1 (coefficient of expansion in volum)
Air 3,67 x 10^-3 K^-1 (coefficient of expansion in volum)
[QUOTE=hightower99]Well just if it was alittle to unclear for you DEISELS ARE NOT AND WILL NOT BECOME SUPER POPULAR DUE TO THE FACT THAT THEY CAN BURN ALMOST ANYTHING THAT CAN BE ATOMISED AND HAS A CALORIC VALUE!!!!! the reasons for there increasing popularity has nothing to do with that it has to do with the things I stated. So next time READ my posts![/QUOTE]
Read my post.
They are coming more populat for that reason. I did not say today smartass.
Once we will maybe not be able to alow our self runn on high grade fuel. Did you think about that? Gasoline is depended on octan and diesels are not.
[QUOTE=hightower99]
Counter rotating= less vibration= less loss due to frictions and stresses! and ball bearings can last along time if they are correctly matched to the job (Like in the ball bearing turbos I see which have been used hard for 120000km!!!)[/QUOTE]
I think you are out of your leaf here. Torbo bearings are moustly plain bearing's. When they are fitted with ball bearings is moustly for high performance aplications. Torbos don't have huge loads on the bearings and the diameter is smal so the peripheral speed will not be high. Smal bearing=high speed.
[QUOTE=hightower99]Yes the scotch yoke came first or very very close to the crankshaft. The normal crankshaft wasn't invented in 1910 and I never said it was! I said that the scotch yoke was old tech by 1910![/QUOTE]
pneuamtic scotch yoke actuators is produced in 100's all ower the world. All this manufacturers don't understand what you do?
[QUOTE=hightower99]the advantages you list are rediculess and they are not true
The crankshaft/connecting rod design gets better torque per [B]smaller cylinder size[/B] (What ever that means?)
A scoth yoke needs 4 parts for a single piston while a normal setup needs only 3. So a normal setup has fewer parts.[/QUOTE]
And how manny parts dos the fantastic Revetec nead?
[QUOTE=Matra et Alpine]If you ever manage to invent then do NOT make that mistake.
Every patent application is kep as secret as possible until it is made public.
This can be up to two years and in some cases is deliberately made longer by the patentee by adding additional claims.[/QUOTE]
This Prototype named 96-5.3-01 (year-version-number) was first started up on the Queens Birthday 1996. WOW. the years in australia is long.
Patents on what by the way? Cams are invented, gear for contrarotating is invented and the pistion concept is invented. Used by Yoke befour.
[QUOTE=Matra et Alpine]BECAUSE ....... as soon as your patent goes public there are companies who will take that patent and work to identify uses not considered AND possible developmetn needs in teh future. These companies then VERY QUICKLY apply for patents for those features. Suddenly a patent holder fo the KEY design finds out that he can't actually develop the product because of these other patents and has to engage in trying to purchase those rights.
Patents which were intially set up to ensure sharing of techincal advances has now become a business in it's own right.[/QUOTE]
So it's not to late to late to apply the patent for usage off the weel yet?
WOW
I can get ritch.
If a engine produce 400Nm at 3000RPM and is converted to a revetec design and then produce 3 times the torque.
Now that means the revetec design should produce 3 times the power too.
Nm x RPM is kw.
kW=Nm/s or kJ/s.
Revetec say they produce 3 times the torque, but the same power?
I find that sounding like a back yard mecanic from Texas.
Sorry guys
I don't buy it.
The two of you can discus advantages about the revetec because I don't care to point out the montain off lies and disadvantages to the two of you.
Good luck.
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i want one of these for my smart roadster
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[quote=stian1979]This Prototype named 96-5.3-01 (year-version-number) was first started up on the Queens Birthday 1996. WOW. the years in australia is long. [/quote]
Please go back and read wher I pointed out that a clever patentee will add additional claims on an on-going basis forcing the patent BACK into application state and not requiring publishing !!
MANY years. One of mine was filed in 2001, the compamy keeps adding a few things and it MAY get published next year ( we're running out of new ideas around the basic concept :) )
[quote]Patents on what by the way? Cams are invented, gear for contrarotating is invented and the pistion concept is invented. Used by Yoke befour.[/quote]
HOW you use something is patentable even if the thing was patented before.
How you use a feature to deliver some NEW capability - additional power or efficiency is also patentable. So I can apply for a patent to use a micro revetec engine (say) to power a next generation laptop :D The engine existed, the laptop existed, my patenn would be for the application !! Anyone writing a patent themself tries to cover ALL those eventualities before it is published. Again, if you go back to what I said earlier post abotu patents then you will understand better.
[quote]So it's not to late to late to apply the patent for usage off the weel yet?
WOW[/quote]
THAT is a correct statement IF you ahve some new applicaiton of the wheel. If you can find a way to use a wheel to cure cancer then you can patent it. You can't manage to patent it to move a vehicle :) ( Interestingly in nano technology there are patent filings abotu nano-hweels, motors etc )
[quote]I can get ritch.[/quote]
only if you are smart enough to INVENT, smart enough to write a cast iron patent for a valuable application AND smart enough to spell :)
[quote]If a engine produce 400Nm at 3000RPM and is converted to a revetec design and then produce 3 times the torque..........................Revetec say they produce 3 times the torque, but the same power?
I find that sounding like a back yard mecanic from Texas.[/quote]
You sir don't understand engines :)
On YOUR assumption then a long stroke engine with higher torque output should ALSO produce higher power than the same engine with shorter stroke/larger bore .... PS: They dont :)
[quote]Sorry guys
I don't buy it.[/quote]
That's OK, we're not asking you to.
Pearls before swine :D
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[QUOTE=hightower99][B]the power generated by the water injection (Which I believe would work better if indirectly injected)[/B] happens when you inject enough water, so that the temperature is halved when the water turns to dry steam. the volume of the air will fall by half but the water will have expanded by more than 1600 times. So if you inject 1cubic centimeter of water dispersed throughout the cylinder as a fine mist, and the cylinder has a max volume of 500ccs then the water will create over 1600ccs of steam. Now lets say that the water is turned to steam when the piston is down far enough to have 100cc in it. the steam alone would give a pressure of 16 bar but it is with all the other gasses making the increase in pressure slightly more. So in the end you are looking at around 300 extra pounds of force per square inch and on a piston with 10 square inches (a small bore motor) then you are looking at 3000lbs. of extra force! that is more than alittle bit![/QUOTE]
Hightower, you're always good for a chuckle.
Water injection does not create power by vaporizing into steam.
[B]Water injection indirectly creates power by removing heat from the combustion chamber via steam vaporization.[/B] This lowering of the cylinder temperature raises the detonation threshold which allows the engine tuner to make more power by 1) leaning out the air/fuel mixture 2) advancing the timing 3) raising the boost 4) use lower octane fuel to make the same power as an engine on high-octane fuel without water injection. Raising the boost yields, by far, the biggest power gains which is why water injection is used primarily on forced induction engines.
While your grasp of physics and their theoretical application is exemplary for a 17 year old, you still fail hardcore at many practical apects of engine design and tuning.
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[QUOTE=PBB]Hightower, you're always good for a chuckle.
Water injection does not create power by vaporizing into steam.
[B]Water injection indirectly creates power by removing heat from the combustion chamber via steam vaporization.[/B] This lowering of the cylinder temperature raises the detonation threshold which allows the engine tuner to make more power by 1) leaning out the air/fuel mixture 2) advancing the timing 3) raising the boost 4) use lower octane fuel to make the same power as an engine on high-octane fuel without water injection. Raising the boost yields, by far, the biggest power gains which is why water injection is used primarily on forced induction engines.
While your grasp of physics and their theoretical application is exemplary for a 17 year old, you still fail hardcore at many practical apects of engine design and tuning.[/QUOTE]
Well You quote what water injection does now. Water injection is only a indirect power adder as of now but if you used it as a cooling system and got rid of the radiator like I said. You could take advantage of all the things you mention as well as increased pressure from the added mass! also a decrease in weight due to no radiators.
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[quote=hightower99]Well You quote what water injection does now. Water injection is only a indirect power adder as of now but if you used it as a cooling system and got rid of the radiator like I said. You could take advantage of all the things you mention as well as increased pressure from the added mass! also a decrease in weight due to no radiators.[/quote]
hmmm, for that to work I think you woudl need MASSIVE compression as if you do not the initial creation of super heated steam will actually prevent the on-going wave front of the combustino gasses.
I'll do the math with my BP petrochemicals friend tonight over a beer -- so no guarantees of accuracy :D
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[QUOTE=hightower99]Well You quote what water injection does now. Water injection is only a indirect power adder as of now but if you used it as a cooling system and got rid of the radiator like I said. You could take advantage of all the things you mention as well as increased pressure from the added mass! also a decrease in weight due to no radiators.[/QUOTE]
Use. water. injection. to. replace. the. radiator. ?.
[I]*chuckle*[/I] Well, let us know how that works for ya.
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fark, ok this is one helluva convo, ive just read page 1 through to 7, and possibly 30% of the terminology and concepts i understand. Matra ya bastard, i envy your intelligence and understanding of cars :D
Btw, back on topic (well the thread title) It's an interesting concept that I hope comes into at least (small) production to show the world its potential and further development if it were provided with more funding. There is always room for improvement in an engine, and simply bagging it in current stage wouldn't be justifiable if there are already plans for improvements with fuel efficiency and what not.
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who said use water cooling to replace radiator ??water cooling will cool the intake charge, it doesnt remove heat from the block and engine parts
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development in current combustion powered engines i think is a stupid concept, we're gonna run outta fossil fuels soon, thus it wont warrant more development into something we wont be able to use into the forseable future, better invest in hydrogen power, and electric cars which can last longer then an ipod and without battery problems
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[QUOTE]who said use water cooling to replace radiator ??water cooling will cool the intake charge, it doesnt remove heat from the block and engine parts[/QUOTE] it doesn't in current applications but I suggested that it is possible and that it would help!
[QUOTE] development in current combustion powered engines i think is a stupid concept, we're gonna run outta fossil fuels soon, thus it wont warrant more development into something we wont be able to use into the forseable future, better invest in hydrogen power, and electric cars which can last longer then an ipod and without battery problems[/QUOTE] we are not going to run out of fossil fuels soon (unless you consider 75-100 years soon?) and even when we due no other form of engine can beat ICEs for the energy concentration!!! Developments in ICE technology is what is going to make things better. Diesels will become the most popular engines because they can run cheaply on totally organic fuel (renewable) and then there is always metal nano dust (reuseable) and hydrogen (renewable)... Electric cars are great for in-city non poluting transport but to fly jets and drive any sort of equipment long distances you are going to need an ICE!
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[QUOTE=hightower99]
we are not going to run out of fossil fuels soon (unless you consider 75-100 years soon?)[/QUOTE]
depends if you want to run your car on coal or not :)
there are very few untapped oil fields left and there aren't any new ones being made anytime soon
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[QUOTE=derekthetree]depends if you want to run your car on coal or not :)
there are very few untapped oil fields left and there aren't any new ones being made anytime soon[/QUOTE]
75-100 years is when the crude oil supply will be too small and expensive to get to be profitable...
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[QUOTE=hightower99]75-100 years is when the crude oil supply will be too small and expensive to get to be profitable...[/QUOTE]
sounds like an extreme upper bound to me...
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[QUOTE=derekthetree]sounds like an extreme upper bound to me...[/QUOTE]
not really there is 25 years there.... Everyone has atleast 75 years of motoring left before everything stops and it could go on for another 25 years after that... but even after 100 years there will still be fuels for use in ICEs
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under current consumption patterns and rates this estimate MAY be true, but developing countries are increasing their ussage of fossil fuels and such to maintain/increase this growth, as a result of getting richer they'll also buy cars
you could argue that cars are becoming more efficient but imho i dont think that they'll become mainstream quick enough to do any measurable good
all of this is besides the point since we know that the supply of fossil fuels wont last forever so why not get an early start on an alternative hopefully renewable and non poluting fuel ??
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[quote=KnifeEdge_2K1]who said use water cooling to replace radiator ??water cooling will cool the intake charge, it doesnt remove heat from the block and engine parts[/quote]
It is physically impossibly for the water not to remove heat from the block and engine parts. Especially since water has such a massive specific heat capacity, it's quite a substantial amount of cooling in the case of water injection.
[quote=PBB]Use. water. injection. to. replace. the. radiator. ?.
[I]*chuckle*[/I] Well, let us know how that works for ya.[/quote]
You guys are very quick to assume. The fact that you've never heard of it has little to do with the possibility of it being a viable idea. It's not just a good idea either - it actually exists.
Bruce Crower (I'm sure you've heard of Crower internals) has invented a highly efficient single cylinder 6-stroke gas/steam engine. Not only does the water injection/steam help make the fuel last longer, but it helps in the cooling process as well. The engine doesn't require a radiator.
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I just read this whole page from 1 to 7, and can't believe what I am reading. stian1979 is the only person here that understands what's happening here.
The revetec engine is equivalent to a conventional engine with a 3:1 reduction built in to it. If it's output shaft is doing 3,000rpm, then it's camshafts, valvetrain, and pistons are doing an effective 9,000rpm.
Therefore it looks impressive to the untrained eye.
If you don't believe the 3:1 thing, then just look at it.
On a normal engine the crank runs the camshafts at a ratio of 1:2. If you have 10 teeth on your crank pulley, you have 20 teeth on your crank pulley.
Because the revetec is a 3-lobe design, it is like having the output shaft (crank) geared down 3:1. So you need to gear the drive to the cams back up 3:1 to get the same piston and cam cycle ratio. So you basically need to have 3 x the normal 1:2 ratio. Or a ratio of 3:2. So if the crank pulley has 30 teeth, then the camshaft pulleys will have 20 teeth. Quite the opposite to the normal engine, and look, it does!!!
[img]http://www.revetec.com/files/_images/DSC_0004.preview.jpg[/img]
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So what does the 3:1 ratio mean? It means they are cheating in some of their marketing.
Take their latest engine test results;
[url]http://www.revetec.com/files/Announcement%20-%2004.05.06.pdf[/url]
The engine they specify is 1.38L. 94mm bore with 50mm stroke. That bore and stroke on a conventional engine gives 1.38L, so they are not compensating for the 3:1 ratio in their effective volume calculation.
So they have tested the engine and get 57kW@4,120rpm. With the effective 3:1 reduction taking into account it is really doing 57kW@12,360rpm.
And they get 140Nm@3,650rpm. But because of the 3:1 ratio they are really getting an effective 47Nm@10,950rpm, and then gearing it down so it looks more impressive. It's false advertising really.
And those effective rpms are correct, because that is what the piston speeds and valve train speeds are equivalent to.
Now they compare their relatively high performance engine (Haltech injection, custom made everything, probably individual throttle bodies) to a low performance production toyota engine. That's not very fair. They then say [b]"Not only are we producing the same power with a smaller capacity engine, but we are doing it at a lower rev which saves fuel. We also are producing more torque than the Prius at a lower rev with a far shorter stroke."[/b]
Lower rev so it saves fuel? what a crock. That is so misleading. Because the revetec pistons go up and down 3 times as much, it will induce 3 times as much air into the engine, and therefore use 3 times as much fuel for any given rpm.
But why not compare the revetec 1.38L engine to a conventional engine in a similar state of tune? One that revs to around 12,000rpm?
Well that would be something like the Kawasaki ZX-14 engine. It is 1.35L, it makes about 140kW @ 10,000rpm, and about 160Nm at about 8,000rpm.
These figures absolutely embarrass the revetec motor. There is no comparison at all!!!
Or the other way to look at it is to compare a ZX-14 running through a 3:1 reduction box, and the revetec.
So the ZX-14 would now be 140kW @ 3,333rpm, and 480Nm @ 2,666rpm.
Compared to 57kW @ 4,120rpm and 140Nm @ 3,650rpm.
Can you people see the difference now???
That shows the revetc is working harder than the ZX-14 engine, and making way way less power and torque!
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[QUOTE=pneumatic]That shows the revetc is working harder than the ZX-14 engine, and making way way less power and torque![/QUOTE]
so basically it's competitive against similar sized car engines but redundant because bike engines do the same thing but much better?
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So the question becomes, why are the power and torque figures from the revetec so crap?
I'm guessing the horrible mechanical inefficiencies of the design.
One problem is the balancing as you've already been told but won't listen to. The opposing pistons are tied together. They move as one in the same direction, so will make horrible vibrations.
And people that say a conventional boxer engine is perfectly balanced is on drugs. Their cylinders do not directly oppose, they are offset. So they don't balance each other.
And people say it's a simple design??? It's got more parts than a conventional engine. Look below;
[img]http://www.revetec.com/files/_images/DSC_0195.preview.jpg[/img]
The shaft through the center is the output shaft. The first and last tri-lobe is fixed to the output shaft, and so is the helical gear on the end (on the left in the pic).
The center gear is connected to another shaft, which is a sleeved outer shaft that fits over the inner main output shaft. But it isn't even a direct connection, there is planetary gears hiding in the middle there. This is because the gear on the left drives the shaft down the bottom, which then drives the gear in the center. But you want the inner two lobes (which are connected to the inner planetary gears and therefore center gear) to be going the opposite way to the outer lobes. So the planetaries are required to reverse that rotation direction. You might need to think about this a bit to understand.
So in order to get the crank mechanism to work, you need two big gears, two little gears, and an unspecified number of planetary gears. This is rather complex, and I am sure quite inefficient from a friction loss point of view. This is sure a lot more complicated than a conventional engine which has only a crankshaft and a conrod to do the same thing.
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[QUOTE=clutch-monkey]so basically it's competitive against similar sized car engines but redundant because bike engines do the same thing but much better?[/QUOTE]
No, it's not competitive against similar sized car engines, because it has to work 3 times harder to do the same thing, and use 3 times as much air, and therefore 3 times as much fuel.
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Why does your argument sound like its coming from an industrial competitor?
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oh, and if you look at this;
[IMG]http://www.revetec.com/files/_images/DSC_0004.preview.jpg[/IMG]
and then look at this;
[img]http://www.vanbran.com/bug/images/conversion1/engine3_l.jpg[/img]
Now I am sure there are better pics out there, but that shows that the revetec engine is in fact running Subaru EJ20 / EJ25 cylinder heads, complete with factory oil filler.
So their 1.38L engine is running cylinder heads from a 2L conventional engine, but is supposed to be much smaller than conventional engines??? Doesn't look like it from that picture.
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I'm by no means an industrial competitor.
I did however write this spreadsheet;
[URL="http://autos.groups.yahoo.com/group/exceldyno/"]http://autos.groups.yahoo.com/group/exceldyno/[/URL]
and therefore am probably more qualified than most to talk about torque, horsepower, rpm and the effects on acceleration.
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there have been so many concepts, quasiturbine, carnot cycle engines even the wankel this is just another trial and a poor one i might add
with this engine, the size or the surface area or volume to area ratio is inadequate, that means the engine will be heating the atmosphere not expanding
and what is this about increasing rpm to produce more power, sure it is done in f1 but it is extremely difficult to produce the same result in real life despite engine size, cbr motor at 600cc goes to 16,000 rpm, thats the best i have seen. this engine is better of being used as an oil pump or a personal vibrator rather than the current use
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[QUOTE=pneumatic]Now they compare their relatively high performance engine (Haltech injection, custom made everything, probably individual throttle bodies) to a low performance production toyota engine. [/quote]
I'll correct myself here, as I found the video of their 57kW 1.38L engine. It's not only using the 2-2.5L Subaru heads, it's also using the subaru intake manifold!
[img]http://www.revetec.com/files/_images/rhl4web.jpg[/img]
So that means their 1.38L is as wide as a 2L subaru motor.
The revetec is probably as tall as the subaru, maybe taller because they need the balance shaft below. The only space saving they could make is maybe in engine length, as they don't need to offset the cylinders like in a traditional boxer motor, but then they need the big gear on the back so it increases the length again anyway.
But then it gets stranger. You see the subaru intake is offset, for the offset cylinders. And the cylinder head cam gear is offset for the same reason. They appear to be using the offset intake and cylinder head drives, then they also must have offset pistons. So at the moment their prototype doesn't have directly opposing pistons, and therefore cannot be any shorter than the subaru motor anyway! In fact with the big gear in the way their motor must be longer.
Below is a pic from an EJ20T which I think they are probably using the manifold and head from. You'll notice revetec are just using the intake bolted on backwards to the throttle body sticks out the opposite end of the engine.
[img]http://www.offroadvw.net/images/ej20.jpg[/img]
and don't get me started on a normal crank wasting all it's power at the start of the stroke where the crank angle is inefficient. Don't these people realise you have ignition timing that gets adjusted to ensure the cylinder pressures from combustion occur at the most efficient crank angles???
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[QUOTE=richy33]You talk alot of crap for a person who knows nothing about revetec or its engines.[/QUOTE]
Not a particularly professional comment.
If you can explain the test data better than I have, and show me where I have made the incorrect assumptions, then please do so.
I didn't say the engine was doing 12,000rpm. I am saying the when the revetec engine is doing ~4,000rpm, the valve train and pistons were doing equivalent speeds to a conventional engine doing ~12,000rpm.
Therefore any torque and power figures from a revetec engine should be compared to a convential engine that is geared down 3:1.
If I am wrong than explain it to me. My observations on the pulley ratio's for the camshafts will be pretty hard to argue against. It's quite obvious what I say is true from simply looking at the photos.
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My 3:1 observation is confirmed by the "let's torque theory.pdf" which is incorrectly linked on the Revetec website. They clearly stated;
[quote]When the power take off point is taken from the Primary shaft, power strokes occurring every 240degrees of driveshaft revolution as compared to a conventional RICE which has a power stroke every 720degrees, the CCE has 3 smaller power strokes per 2 revolutions equating to a conventional RICE having 1 large power stroke per 2 revolutions. [/quote]
Where CCE is the revetec and RICE is a regular internal combustion engine.
That is what I and Stian have been saying. On a normal engine you make power every 2 turns of the crank, the piston goes up and down every turn. But with the Revetec has 3 lobes, so the piston goes up and down every 1/3 turn. It therefore makes power every 2/3 of a turn. Therefore it's internals (piston and valve train) are running 3 x faster than those of a normal engine.
So don't try to argue that, the revetec website even says it.
Even the leap report says the engine produces 6 power strokes per revolution. This compares to 2 power strokes per revolution for an equivalent conventional 4 cylinder engine. This is more proof the internals are running 3:1.
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[QUOTE=richy33]You do not times the rpm by three, the gearing is made so that the output shaft runs 3:2 so if the output shaft is running 4120rpm, the internals are running about 2746rpm.[/QUOTE]
If this is true than it explains how your getting the subaru valve train to survive such relatively high revs.
If it is true, then Revetec is gearing it up 3:2 to try to get a usable rev range out of it. This means the internals will be effectively geared 2:1 rather than 3:1.
So at an output shaft speed of 4120rpm, the main trilobe shaft is doing 2746rpm (as you have stated). But the pistons are going up and down 3 times more than a conventional engine, so the valve train and pistons are effectively seeing 8240rpm.
So if what you say is true I should be comparing this engine to a conventional engine geared down 2:1. Fine, let's look at that.
First you could compare the 1.38L Revetec vs a 1.3L Suzuki Hayabusa engine as is;
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As you can see comparing them with the Hayabusa "ungeared" is not very far due to the much much higher rev range.
So if you add a 2:1 gear reduction to the Hayabusa then the rev ranges become comparible, and the power strokes per revolution of each engine should become the same. As you can see on the attached graph, the Hayabusa engine is so much better, there is no comparison at all. It has nearly double the power and double the torque.
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I think this quote says it all;
[quote]"The first thing I did was go to Queensland Institute of Technology. I'd come up with the concept but I wanted someone else to verify what I was doing. I presented (the idea) to them and, first off, I said that I was going to increase the level of thermodynamic efficiency beyond 50 percent. They laughed at me. They laughed, so I said 'well, I'll prove it to you.'"[/quote]
I went to QUT, and I know they get people come in there every year claiming they've got a new fantastic idea, so it's not surprising they laugh. No-one has "proved it to them" yet.
The revetec does have some interesting aspects to it's design, but it is also surrounded by intentionally misleading marketing.
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[QUOTE=pneumatic]I went to QUT[/QUOTE]
UQ represent!
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Revetec has ben under development for about ten years. At the moment we have not been interested in performance engines so let's refer our engine design to performance in regards to fuel economy. We have produced a very flat torque curve which provides great acceleration right through the range. Our engines have been tested by automotive companies overses and we have replicated this . Another thing is that the fuel consumption remains constant under full load right through the rev range which is not seen in any other engine in the world.
I'll get one thing straight right now. We do not release most of the information about our engine as we protect our technology. We have not disclosed our actual design and guiding system for the pistons. We have almost perfected the design and are currently building our next model which all engines in the future will be based on. We have drastically reduced the size of our engine and reduced the amount of components. We have had no problem with gearing. Because of our new piston guiding system, we have no problem with piston twist.
Our engines in the past have been strictly development engines. Every time we change the Trlobe cam design the balancing changes. This is why up to date we have not balanced any of our engines as it has not been required for the type of development work we have been carrying out. Our new engine is fully balanced. Our reciprocating mass is smaller than other engines of the same capacity, and our stroke is shorter reducing the mass required for balancing. We used the subaru heads on our last engine purely because they roughly suited our last engine layout and our next engine will use heads developed in-house.
I think that most people don't understand our engine due to the fact we have not released certain information. I'll tell everyone now that the cylinder heads are operating at the same speed as a conventional engine. ie. The pistons stroke 2 times (1Xup and 1Xdown) per output shaft revolution (the same as a conventional engine), so there is no overspeeding of the engine's top end. Please remember we have not released all engine features and operation information. You will all have to be a bit patient.
I'll also state now that the formulas that work out power and torque do not work on our engine so all of you engineers that are trying to work out figures for our engine, your standard engine calculations will not work. We have proved this to several large automotive manufacturers and the like plus the figures we get in actual testing verify this.
A development program is just that. Trialling different engine layouts to evaluate different design features. Trialling a new design always creates unforseen problems and failures which then steer the design into the correct layout. Failures are normal for a development program, as with every new design longer endurance testing takes place. We are now in a postion that our next engine is ready for the testing required by engine manufacturers to evaluate in performance, fuel economy and initial endurance testing. Every automotive manufacturer in each region has different operating enviroments. So each engine has to be tested and modified to reach those standards in each region. Say for instance that an engine in Australia is different from one in another country even though the car model is the same. This is why the final endurance testing is not done by us rather an by the automotive company evaluating the engine technology for production.
What I can say is that we are nearing the end of development that is required before production of our engine is performed.
Stay tuned to our website [url]www.revetec.com[/url] over the coming months as soon we are going to release info about our new engine. We are very excited about it and it will suprise everone in the engine field. We have now lodged a new patent world wide on the new design.
I will check this forum time to time so if you have any questions please post them as I will try to answer them when I have time.
Cheers
Brad Howell-Smith
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The comment about misleading marketing is incorrect. All marketing the company has released is acurate. We are not bound to release all information about our engine and for security of our technology we reserve the right to hold back information. I have just returned from overseas where I presented to a board of about 8 senior engineers from a leading automotive supplier and the statement from them was "this is a step up technology".
We have proven in actual testing our flat torque curve and a flat fuel usage over a varying rev range. This has been done by a leading automtive company in their facility, fully independantly. I know many of you out there have a lot of questions because you don't have the full picture about what we are doing and I hope to disclose the rest of the information soon. I can say that we have presented to many of the world's top engine manufacturers including 2 Japanese car manufacturers and we have been able to satisfy all their questions posed to us. This technology is hard for them to comprehend so I don't expect you all here to understand what we are doing from the limited information.
As regards to the 1.3L Suzuki Hayabusa engine. Outright performance is not what this is all about. This engine is all about saving fuel by providing consistant torque throughout the rev range reducing the need to rev an engine into the higher power and rev range. By doing this fuel consumption is reduced dramatically. No doubt performance models will evolve to exceed conventional engines in the performance area. I know most of you are interested in the perforance area but I'll tell you now that that is not where most of the market sits. The current engines are directed at markets where fuel usage and pollution problems exist.
Regards
Brad Howell-Smith