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#31
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I'd also forgotten that they have alignment shafts that retain piston alignment so would suggest removal of "slap" allowing a much smaller skirt and possibly lower mass piston. Quote:
They are NOT subject to the needs of thinness of a conrod to be able move the piston. So they dont' need to be as substantially built. They are much shorter in throw too. The engine wins because it does NOT use a crankshaft -- which has counter weighted lobes -- and is more efficient in power extraction per combustion because there is no angular vector from a conrod. Quote:
The effect of gravity is MINISCULE relative to the combustion forces in the engine ![]() Quote:
Boxers are WIDELY used in light planes because then the packaging can actually be an advantage !! You dont' get many places where reliability and performance are any more important than a light aircraft ![]() Boxers are a BIG win when you go air=cooled. But by the time you add a water jacket then a 4 isn't as efficient packaging as a straight. Quote:
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THE big benefit the Revetec design goes for is the removal of the angular forces a crankshaft imparts. SO removing all the necessary design to cope with those stresses and wear.
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"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell' Last edited by Matra et Alpine; 02-24-2006 at 01:00 AM. |
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#32
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The bearings on a normal piston and rod conection the movement is only 2cm per revelution since it only go back and forvard. The revetec has to roll all the way along the crankshaft rotation witch mean it has to travle 1/3 of the distance of the shaft per work cycle. That delta shaped shaft has to be heavy! and don't tell me they wont nead a extra gear mecanism to runn those contra rotating. Alfa tryed a 12cyl boxer in F1 and it did not win anny championship (it did not prove reabile) I read about revetec a couple of week's ago and the more I think the less I like it. If I use a normal engine and runn it at 3 times the revelution and use a 3:1 gearbox I will have the same results as this guys did - I don't nead to waste time on all that engineering. It's a funn project, but so was my steam engine |
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#33
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By only takign one variable it creates a false impression. I'm not sure what you are trying to say. Quote:
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Mating surfaces and materials are what makes for bearing resistance and wear. Again, it's not clear what you are trying to say. Quote:
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it never really had any chance to be developed to prove itself ) didn't make it work and so all flat 12s are bad ? hmm Ferrari WON CHAMPIONSHIPS with a flat 12 and the greatest sportscar of all time the Posrsche 917 used a flat 12 Quote:
THe BIGGEST issue in engines is the piston crontrol and the crankshaft componetnry. The Revetec is one of many that are utilising modern methods and materials to provide different linkages not possible in the past. They've published numbers better than alternatives and have a deal with Honda to build in China. Quote:
AS said earlier, nobody is going to bring out an engine twice as powerful or efficient as any other competitor. Engine design isn't about that anymore that all happened 80 years ago But this does have definable engineering improvements and it woudl be nice to see it flourish and give options.
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"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell' |
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#34
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But the average Nm output is only 2,9 of what a normal engine can do at the same RPM. Why? ask yourself this. Evidence I find trough experience and reading betwen the lines. how long is the distance around the camprofile on revetec's crank? the bearing on the pistion has to go this distance in case you did not notice. Tradisjonal bearings only nead to travle a short distance and then back in the connection at the pistion and the distance round the crank that is short compared to the revetec. This statement say it all. Quote:
Sorry but it's not posible. I can at least tell you that it's more heavy than a normal crankshaft can be made. Ferrari, meclaren and others make supercars with v engine. Why not the boxer? The disanvantage of space is gone when you have mid engine cars. They get a lower center of gravety so why not use it? You can only refear to 1 race car doing good on the track with a boxer? Why was this linkage not posible in the past? So just because it's build in China it's good? Newer heard that one befour. Otto and Diesel was engineer's so they knew what they where doing and they did it well. |
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#35
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I found this on a other forum I'm a member of 3 week's ago that I think it's a good statement. It's from the FIA forum.
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#36
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It's "pseduo science" like that that raises the question marks over the comments ![]() Quote:
You need to learn a bit more about bearings See comment above.Quote:
And why do engines NOT achieve the "perfect" numbers ? Why are some engines more "efficient" and get closer than others ? Yep. Think it out. As I have said the thing the Revetec is trying to deliver is the recovery of the loss in power from the operation of a crank. A significant loss and wear factor in an engine. Quote:
Look at the lobes opposite to the pistons for balance !! It clearly have to find you the quote rather than taking my word that I'd read an early press release saying the bottom end was lighter Did you search the previous UCP posts ??Quote:
![]() NOT the engine per-se --- as I said. Quote:
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( See the Polish moving piston valves engine that the guy built in his garage L) ) There are many innovators out there trying the new ideas that in theory address limitation of our current designs. It goes on all the time. The difference is that thanks to the internet we can see, explore and critique these solutions in a way not possible in the past. Quote:
HONDA is the company reputedly in the deal. Tells a lot on your thinking process that you ignored that it might be a MAJOR PLAYER and instead tried to make it sound negative because it was China ![]() All it did was remove respect for your comments. Quote:
And what about all those hundreds of engineers who were developing engines at the same time ? How much do you know about engine development and history ? Watt, Moorland, Brown, Matteucci, Stirling, the list is HUGE.
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"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell' Last edited by Matra et Alpine; 02-25-2006 at 06:03 AM. |
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#37
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![]() Lets take an engine that needs 2 valves per cylinder so we need 8 cam lobes on a 4potter. If you used a pushrod then it's a no brainer, no difference If hte engine doesn't rev hard that's a distinc possibility ![]() If we assume worst cases -- ie over head cam then you need a drive pulley - which is VERY light and then the 4 lobes and the 4 connecting shaft sections in each head. SO the only difference is the pulley and once shaft connecting section. NOT A LOT ![]() If you go twin cam to get optimum valve angles then it's 2 extra pulleys and 2 extra connecting shaft piece ( ie abtou 1" long, 1/2" diameter. ) SO sorry, it's RUBBISH to harp on about all this "extra weight" ![]() As someone who has spent too many hours in garages and workshops trying to minimise weight in race/rally engines it's a NONSENSE to make multipel cams out to be a disadvatage. the decision to go multile VALVES carries the penalty not signifactnly where you put them ![]() THe writer also confuses efficiency and power. IF you can make an engine 5% more efficient then revs etc are irrelvant as you then use gearing to make that engien operate in that optimum area. It's. I suspect, why they went for pumps initially as they are run at their optimum efficiency for long times, same with aircraft engines. Cars with proper CVTs are the same.
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"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell' Last edited by Matra et Alpine; 02-25-2006 at 06:07 AM. |
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#38
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Are you the designer of this pice of crap?
You try to defend something that annyone can see is a hopeless idea. Do you know how mutch is lost in a engine because of friction? It's nothing compared to what you loss in heat radiation, coolong water and heat trough exhaust. It's a none exsisting problem. If someone want's seriosly to make some diferense they would put there intention to experiments with materials that don't nead cooling and ways of heat rescovering. Same HP and 3 times the torque is inposible. kW=Nm x RPM This is the same for sterling, steam, diesel, otto, wankel, 1 shaft gasturbine, 2 shaft gasturbine, 3 shaft gas turbine and ac/dc motors. This formula is the same for anny engine design. kW=kNm/s=kJ/s You can argue this all you want, but it's a fact that will not go away. Go to a tecnical high school and ask about the realationship betwen RPM,kW and Nm, but you will probartly say the guys there have no clue what they are talking about. You don't acept the conserns I have about boxers, but you make up your own as a exhuse for it not to be the leading design(do you think revetec is going to remove those conserns you came up with yourself?) The gas turbine is advanced and the first one was buildt in 1906. The Napier deltic was advanced and build in the 40's. What is so special with the revetec that made it inpoible until now when computers show up? Otto and Rudolf was good enginers and so was sterling. He's engine is one of the moust efficiant, but it are to slow to speed up so sadly enough it can't be used for mutch. |
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#39
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And a designer who can recognise others ideals and efforts. Quote:
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Is an improvement only to be considered if it makes EVERYTHING better ? ![]() As I have pointed out what they are mainly concerning themselves with are the losses that offset crank in a normal engine causes. It's IS significant and when you tune an engine up becomes THE most common cause of engine failure ![]() Quote:
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THAT is what was pointed out to you> You've got 1/10th of the information about an engine and implying far too much from it ![]() Quote:
)[quote](do you think revetec is going to remove those conserns you came up with yourself?)[/quote} I doubt Revetec will remove the problems a boxer inherently has. BUT that doens't mean they can't make a more efficient "boxer" and where boxer engines HAVE proven themselves that they may be better !! Do I think as Revetec could ever be a racing engine ? No I doubt it, but that's not what they're setting out to do ![]() Quote:
"advanced" for their day is the key terms. You'er getting all mixed up now ![]() Quote:
)At least you NOW recognise that there are many designers and who knows in 10 years someone may hold the Revetec up as an important evolution and maybe they'll say that it can't be used for much> Does that remove from the engine objectives ? No. But you seem to be working hard selecting information shared to try to avoid that the Revetec is offering something different and MAY be better and has at least got ONE MAJOR company interested enough to think about production. ( That's more than Da Vinci managed with HIS engine )
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"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell' Last edited by Matra et Alpine; 02-25-2006 at 09:38 AM. |
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#40
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I've moved all this here to save the annoyance of those interested in F1
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"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell' |
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#41
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unlike matra i do not feel a moral obligation to help the stuborn and stupid people of this world ...
so here's my reply ... " You sir are an idiot." |
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#42
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I actually like the Revetec concept as it is a new way of getting work out of the reciprocating piston. It certainly has some advantages going for it but well...
It didn't take me long to figure out a way for the revetec engine to work in a inline configuration. The solution I found also meant that they could run an even number of firings per revolution and I would suggest 2 (as in a 2 lobed cam) as this would allow better output speeds and slightly better effciency over a wider range of speeds. Also it strikes me as odd that nobody has mentioned the most novel part of this system. The fact that the crank assembly translates the linier motion of the piston into rotary motion of the output at peak efficiency faster than a normal crankshaft, making better use of the higher pressure gasses in the chamber. To some of the critics: the 2.9x more torque you keep quoting is actually taken from a comparision between a single firing in a revetec versus a normal engine! the graph for the results is on the website somewhere... oh and there are engines (mostly rotary) that show pretty large gains in efficiency over the humble piston engine (which has many fundamental flaws) I believe the Quasiturbine a proud canadian invention shows much better innovation and promise.
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Power, whether measured as HP, PS, or KW is what accelerates cars and gets it up to top speed. Power also determines how far you take a wall when you hit it Engine torque is an illusion. Last edited by hightower99; 02-25-2006 at 01:30 PM. |
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#43
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I had tried to point it out to him "ht", but as you see failed
![]() Yeah the Q is another one of the interesting ones around. I was concerned that it would suffer as the Wankel does of trying to maintain a good cylinder seal. Not seen any protoypes yet. Btw "French-Canadian" --- so there will be HALF of a flaw in it ![]()
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"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell' |
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#44
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First sealing is no longer an issue for rotary engine like the wankel or Q they figured out what to make them of (aluminium-carbon alloy) and second check out the site (it is in english too!) and you can see a few prototypes...
And I know that it is French canadian and unfortunately I do not fit the stereotypical "I hate Quebec" mindset. I see Quebec as having some of the brightest minds on the planet...
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Power, whether measured as HP, PS, or KW is what accelerates cars and gets it up to top speed. Power also determines how far you take a wall when you hit it Engine torque is an illusion. |
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#45
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PS: j'ai les voitures francaises. J'ai du apprendre comment lire et parler le francais Quote:
![]() ( Sorry long-standing joke, the French will always have some fatal flaw that undermines the pure perfection )
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"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell' Last edited by Matra et Alpine; 02-25-2006 at 02:53 PM. |
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