2 stroke thread (with occasional F1 relevance!)

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
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PlatinumZealot
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Re: 2 strokes Formula 1 engine

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Edis wrote:
Richied76 wrote:its just pure inefficient. you "dirty" up your fuel or send more fuel out the outlet valve. Its probably going to cool the outlet gasses which is all well and good if you worried about Nox emissions but not good if you want to burn away as much Co2 as possiable. Besides how you going to lubricate it? have a sump in a two stroke? or you going to let it run dry when its a 4 stroke? theres no NEED for this engine. especialy with VVTI, turbo charging, DPF filters, ERG valves, catalistic converters.

All things that were made to allow a 4 stroke engine to provide more power and produce less harmfull emissions. oh and the last 2 sroke car engine i remember was a small car producer from austria who produced a 2 seater 1.2ltr L4 two stroke...untill it was banned for being dirty..onto of being loud and guttless
All larger two stroke engines use separate spool pumps (not the crankcase), direct injection and regular pressurized lubrication to avoid the problems normally associated with two strokes. That you blow some air out through the exhaust is of no concern since the fuel injection doesn't begin until after the exhaust port has closed.

Turbocharged two stroke engines like these are capable to exceed 50% efficiency
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That efficiency is partly due to the large size of the engine believe it or not.
The scale if irreversibilities of the combustion gases compared to the control volume is so small so your isentropic efficiencies are much higher.

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flynfrog
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Re: 2 strokes Formula 1 engine

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n smikle wrote:
flynfrog wrote:
WhiteBlue wrote:Apart from the fact that there will be a brand new four stroke turbo formula from 2014 you also find a lot of environmental concerns against two stroke engines. Unless something fundamental changes I see practically no chance in the next decade. Two stroke engines are not fuel efficient and they have no closed lubrication circuit. The FiA will be dead against the technology.
you might want to educate your self a little the new two strokes are cleaner and more efficient than there 4 stroke counter parts for the same power.
Have a source? Or example? Other than politics, There must be a reason why they are not common on the roads now.
Imagine two cylinder two stroke turbo city cars, dream come true? Looking at the way a 2 stroke works the window of intake is so small that you have to run really high boost to clear the exhaust air out (depending on the degree of EGR that you want of course). but yes, 18000 rpms would sound like 36000 rpms with a two stroke. Power would be nasty!
Merc wrote:But OptiMax’s proprietary two-stage injection system creates a remarkably concise combustion cycle – giving you the fuel conservation and lower emissions of a four-stroke. A win/win, win/win any way you shake it.
http://www.mercurymarine.com/engines/ou ... t/optimax/


Just an ad I know but these engines are certified by CARB (the people that killed the two stroke in cali) Not much time to find links right now.


You wouldn't need any boost at all to clear the exhaust out. A good pipe will get most of it. Very light boost will clear the intake charge quite well. Lost of the snowmobile guys around here are running turbo two strokes at 15-20PSI until things get melty.

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FW17
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Re: 2 strokes Formula 1 engine

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But the mercury engines are not designed for going up and down the rpm range as a racing or road car engine does. So can it be really relevant?

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flynfrog
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Re: 2 strokes Formula 1 engine

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WilliamsF1 wrote:But the mercury engines are not designed for going up and down the rpm range as a racing or road car engine does. So can it be really relevant?
relevant to what?

Tommy Cookers
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Re: 2 strokes Formula 1 engine

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It seems that 2014 F1 has the bore fixed at 80 mm
This corresponds to a bore:stroke ratio of about 1.5, ie in line with our experience of real-life engines.
This will allow typically 12000 rpm.

At present F1 has a B:S ratio of nearly 2.5 ( to allow the engine life at 18000 rpm)

This is a huge difference.

The 2 stroke would have much better prospects in 2014, because it would would not be particularly limited in its porting capability at !.5 B:S ??

(unlike the present rules, where it would be strangled by its porting limitations at 2.5 B:S/18000 rpm)

Speng
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Re: 2 strokes Formula 1 engine

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Unfortunately all this discussion is moot as the proposed 2014 rules require the engines to be 4 strokes.

Sombrero
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Re: 2 strokes Formula 1 engine

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Gerhard Karl Mitter made a lot of experiment with 2-3 cylinders 2-strokes engines for Formula Junior and build an unraced 4-cylinders 2-strokes engine for F-2.

The Mitter constructions is 2-stroke 3-cylinder own designs got the big names angry!

:arrow: http://www.youtube.com/watch?v=Je4rtsTJFfY

A motor sports pioneer, a pedigree driver and a man hobnobbing with the big stars and insiders of the scene. Inside Racing presents private footage from the life of a brilliant racer and mechanic !

:arrow: http://www.youtube.com/watch?v=vy_9QNtrjko

Enjoy!

MadMatt
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Re: 2 strokes Formula 1 engine

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Here is the article I wanted to talk about which I finally translated (I apologize for the mistakes, English is not my native language). I hope it will be of much interest for people here.

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One day before the 1979 Italian GP, Tissot, which is one of Team Lotus sponsor had invited few journalists to go with Colin Chapman and Carlos Reutemann in a visit of its ultra-modern factories of the small Swiss "clock city" of Le Locle. That visit was even more interesting because we are actually starting to talk that Heuer is gonna retire from the automotive world to get into micro-watchmaking, while Tissot's efforts have been growing since this year.

But for the motorsport fanatics, the most interesting moment of this day was the presentation of a new 1500cc flat six turbocharged engine.

That engine hasn't been built by a commercial manufacturer, but by the engineering school of the Neuchatel "state", located precisely at Le Locle. It is the Pr. Pierre-Antoine Jeandupeux who has directed the studies and the build of that prototype. While the Formula 1 etiquette has been associated with his name, we are going to see later that the engine is not in good terms with the regulations and it is more under a tool for the students-engineers that this engine should be considered.

The primary characteristic of this engine is that it is a 2 strokes engine. We immediately see there a reduction of about 50 Kg of weight : no camshaft, valves, pinions. But also a theoretical potential of power higher than the one of a 4 strokes engine, because at each piston fall stands an engine-stroke.

That can be obtained as long as the large technical problems have been solved, especially if we consider that this engine is turbocharged.

The intake in the combustion chamber of a classic engine is being made by the compression of the gas in the sump while the piston is going down. Here, it is the compressor that does this job, which solves nicely the lubrication problem (the sump is conventional with oil pump lubrication and it is not needed to mix the oil and the fuel). On the other hand, to start the engine, it is needed to rotate the compressor. This is the number 2 problem.

But the particular originality consists not only in launching the turbocharger to start the engine, but also to reduce the lag, by using a thermal reactor in the exhaust : the exhaust has a volume in which we inject fuel that we burn (like in a turbine) and the gas replace the exhaust gases to rotate the turbine which is connected to the compressor. We know this system in France, it is the Hyperbar process, still underdevelopment. The minor downside is a higher fuel consumption (M. Jeandupeux talks about 20%) but more important is the need of that added combustion chamber which enlarge the engine capacity to the eyes of the governing body. At the moment this engine is illegal for Formula 1. To adapt it, the reactor should be replaced by a turbine, whose capacity should be measured according to the formula made by the "sport code". Then the engine capacity should be reduced by the turbine capacity.

We see that this eventuality is quite far away, but it doesn't bother Pf. Jeandupeux : "Develop and setup the engine will take at least 5 to 10 years to my students, its the only thing which matters !" He is perfectly right, and many young students-engineers will envy those of the Neuchatel school...
On a side note, I am gonna graduate from this exact school in less than 2 months and that engine is still there, unfortunately still in the same state, but its still nice to look at it thinking about what may have happened if they had time and money to finish it ! :)

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gcdugas
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Re: 2 strokes Formula 1 engine

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Nowhereman wrote:For F1 applications, a 2 stroke derrivative would dominate in the HP / weight catagory.
2 strokes can be much lighter than 4 stroke designs.
I also believe that do to the common pratice of the engine being a stressed member of the chassis, a 2 stroke design could be developed to promote better chassis stiffening than it's 4 stroke counterpart.
The F1 should allow 2 stroke designs to compete with 4 stroke designs if F1 is truly the pinnacle of motorsport.
The problem with F1rules is that they are under pressure from the participants to keep costs down and thus many things like CG height, camshaft location, B/S ratio, materials etc. are all prescribed. And the biggest limit on engineering development is the Std. ECU. All these things and more conspire against F1 truly being the pinnacle of Motorsports. Remember, there was a time around 1985-89 or so, when F1 had V8s (Cosworth), V12s (Ferrari), turbo inline 4s (BMW) and turbo V6s (TAG Porsche) all racing on the track at the same time. Honda had a V10 back then and raced a V12 the very next season.

Right now I would say that LMP1 cars allow the most engineering freedom. Plus the LeMans series rules makers are approachable and open to entertaining thinking outside the box. So along comes Audi and they say: "We want to explore diesel technology." and the rules makers said: "OK, have a go at it." The rest, as they say, is history.

Yes the direct injection two-stroke technology deserves exploration. For years engineering journals have spoken of the direct injection technology being developed by Orbital. Now consumers can buy outboard motors featuring it. Along with these high-tech clean two-strokes in the outboard motor market, ultra high-tech 4 strokes are being developed with incredible reliability and needing almost zero service/maintenance.

As to the benefits of two-strokes over four-strokes...

The main benefit of a 4S is that the power stroke goes all the way to BDC, better scavenging/pumping, easier lubrication. The draw backs are half as many power strokes per revolution and an inefficient power consuming valve train that is heavy and complex. Inefficiencies also arise from having a bunch of reciprocating mass. Comparative size and weight between a 2S and a 4S greatly favor the 2S.

The main benefit of a 2S are almost zero losses caused by valve opening and closing and 2S motors have twice as many power strokes per revolution, combustion chamber design and shape is virtually unlimited. Smaller size, greater simplicity, less weight all are huge benefits enjoyed by 2S. The draw backs are a shorter power stroke, lubrication challenges, emission challenges, exhaust pipe size and routing issues and a inferior scavenging/pumping effectiveness.

High-tech direct injection 2S motors pretty much have overcome the lubrication issues and the emissions issues. We must note that the overall scavenging/pumping effectiveness only needs to approach 50% relative to that of a 4S since the power strokes are twice as frequent before the trade-off reaches parity. These engines definitely have a bright future ahead of them in automotive applications and I wouldn't be surprised to see them appear in LeMans type racing in the next five years.

There have been many attempts at novel solutions to the 4S valve train issue. One of the most promising designs is the Bishop Valve system. http://home.people.net.au/~mrbdesign/PD ... echBRV.pdf Great performance numbers and efficiency have already been achieved on bench models as detailed in the article.

There are two different designs exploring the same basic principle. One design has two "tubes" per cylinder and the other utilizes just one "tube". The one tube design allows for huge valve area but suffers from poor spark plug location and the best solutions involve two synchronized spark plugs which present challenges. The two tube design has less valve area but an ideal spark plug location. I know it is only a matter of time before the BRV engine sees mass production. The benefits are just too many. lighter, simpler, smaller, far lower valve train losses that involve no reciprocating mass.

This has been discussed on this forum here viewtopic.php?f=4&t=7486&start=0 BTW, integrating the head and cylinder into one piece solves the "head bolt issue" raised by a forum member.
F1 could have been the vehicle that brought the BRV engine to notoriety but politics, Max Mosley and fear killed it. Now another series will introduce it to the masses and F1 will been seen as "high-tech" as push-rod carbureted NASCAR dinosaurs. Too bad. The .pdf article ends with this sad commentary...
With advantages in height, weight, C of G, elimination of inertia loads, breathing and greater durability Bishop is confident that, had the technology not been banned, it would have become the technology of choice for racing engines.
This technology has considerable potential in production applications where it has the additional advantages of fast combustion, low valve drive torque and high compression ratio capability. Bishop anticipated that demonstration in F1 would provide the impetus for the considerable further development required to bring this technology to production. Regrettably F1 has abandoned its long standing raison d’être to “improve the breed” and replaced it with “protection of the status quo”.
Innovation over refinement is the prefered path to performance. -- Get rid of the dopey regs in F1

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Jackuar
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Re: 2 strokes Formula 1 engine

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Not much knowledge about the technical details but I know in bikes, 2-strokes are noisier than the 4-strokes. If same is the case with cars, then it would be a pain in the ... ears!
Finishing second is being the first one of losers....

Tommy Cookers
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Re: 2 strokes Formula 1 engine

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Tommy Cookers wrote:
All cylinder ported engines are relatively starved of port area as larger bore:stroke ratios are used (for higher power via higher revs). This is broadly a historical trend, associated with broad historical progress in fuel quality.

Poppet valves are advantageously aligned wrt gas flow and size, and to use overlap. Crucially, poppet valves areas are relatively larger at larger bore:stroke ratios. F1 uses this to great advantage, now that valve action is so improved via pneumatic springs. F1 b:s ratios are now around 2.4:1 (this is startlingly large)


Would the 2 stroke prevail in current F1 ?

GP motorcycle 2 strokes always had relatively low bore:stroke ratios to allow sufficient port depths (a fraction of stroke). Shortening the stroke for more revs and power wouldn't work because the port areas would not increase. All these engines had b:s ratios close to 1

GP motorcycle noise limits introduced about 35 years ago were very hard on the 4 stroke, the last ever (flat 4, never raced) MV Agusta failed the noise test at full rpm when producing no power (driven electrically) ! The last MVs that actually raced made as much noise as a grid full of 2 strokes. They were competitive, having a stroke short enough to rev about 40% higher than the 2 stroke
...... the natural form of the 2 stroke exhaust system was/is a 'divergent/convergent type with a tiny tailpipe, the 4 stroke always had then 1 long shallow divergent 'megaphone' for each cylinder, so usually 4 'megaphones'
this was conspicuously noisy
Last edited by Tommy Cookers on Fri Aug 03, 2012 3:53 pm, edited 1 time in total.

Cold Fussion
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Re: 2 strokes Formula 1 engine

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Is there any technical/physical limitations of running a normal 4 stroke engine design but with using a 2 stroke cycle?

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FW17
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Re: 2 strokes Formula 1 engine

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Cold Fussion wrote:Is there any technical/physical limitations of running a normal 4 stroke engine design but with using a 2 stroke cycle?
http://thekneeslider.com/archives/2008/ ... ke-engine/

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flynfrog
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Re: 2 strokes Formula 1 engine

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Jackuar wrote:Not much knowledge about the technical details but I know in bikes, 2-strokes are noisier than the 4-strokes. If same is the case with cars, then it would be a pain in the ... ears!
um you have that backwards. Look at the post below yours.

iceracer
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Re: 2 strokes Formula 1 engine

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well!..here some real engines that i race every winter , iceovalsleds..

i dont have a real V10 F1 to look on...( at moment) BUt i do have plenty of other 2 stroke high reving high power, vintage-Yes-you hear me!..-Vintage !...twostroke engines..
iam on the safe side of EGT meters... my 340cc tvin twostrokers put out +300hp/litre -no problem!
dyno at +105hp/10.600rpm twin 340cc spirit(suzuki)
my engine "last" for ever...it can easily with my work be made to put out +130hp/litre but then endurance will go down..
.n thats in my garage..not in a billion dollars Honda f1 hightech factory!...
conclusion is that there are "powers" thats wants 4 stroker..more than 2 stroker dispite the powergains for the trostroke engines..Sad but true!..
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