Absolute Redline!

[Vortex347]

Hi all, before they started bringing in rpm limiters it was claimed that engines (3l v10's) revved to 21000 rpm and they brought the rev limiters in to prevent the rpm from continuously increasing. I was just wondering what is the absolute limit of rpm they could have reached if they kept going up? I'd assume it would have something to do with how fast the fuel combustion can take place but i'm not too sure.
Based off of the fuel and engine components I'd assume it would be 24000 rpm or something like that??
But that's just a guess

Very curious to see what results you guys yield!
cheers guys and thanks in advance!

[tanmay324]

Small engines used in aero models can rev upto 25-30k rpm. But most of them are two strokes.

[Vortex347]

Awesome to know! but it's a two stroke so I would think it could run higher than a 4 stroke rpm no? it'd be insane if they could get that kinda rpm out of an f1 engine
What about for an naturally aspirated v10 f1 engine shall we say

Cheers for the quick reply mate! much obliged

[Juzh]

Highest revving F1 engine was a cossworth V8 from 2006 and it was 20.000 rpm. V10s never revved that high. I remember them being maxed out at around 19.000 or just a bit more.

Anyway, I believe this is what you're looking for:

Without the engine freeze and limit on rpm, what would these engines be capable of ?

Without the rev limit we would have continued to pursue greater rpm until we became limited by the physics of the combustion process and diminishing returns due to increased friction with increasing rotational speed. Without any other new regulatory constraint, I imagine we would have reached over 22,000 rpm by now and would have found a further 75 horsepower (ie +10%), equivalent to a lap time gain of around 1.5 sec at Monza.
Without doing the development work, it is difficult to judge the level at which engine performance would have converged at the limit of the technical regulations. The same effects that have been pursued in the frozen era (exhausts, mapping etc) would have been of interest, but the priorities may have been different.

http://media.renaultsport.com/Australia ... ml?lang=fr

[rgava]

Perhaps you would like to read this thread: http://www.f1technical.net/forum/viewto ... f=4&t=7457

[PlatinumZealot]

Hi all, before they started bringing in rpm limiters it was claimed that engines (3l v10's) revved to 21000 rpm and they brought the rev limiters in to prevent the rpm from continuously increasing. I was just wondering what is the absolute limit of rpm they could have reached if they kept going up? I'd assume it would have something to do with how fast the fuel combustion can take place but i'm not too sure.
Based off of the fuel and engine components I'd assume it would be 24000 rpm or something like that??
But that's just a guess

Very curious to see what results you guys yield!
cheers guys and thanks in advance!

Toyota said 23,000 to 24,000 rpms.. but not without huge losses.

[Vortex347]

Thanks for the reply mate

Toyota said 23,000 to 24,000 rpms.. but not without huge losses

Can i get some clarification on this please. what is the limiting factor/s this is based off and what are the huge losses
cheers

[hollus]

Have you read the old thread that rgava posted?

[Tommy Cookers]

Thanks for the reply mate

Toyota said 23,000 to 24,000 rpms.. but not without huge losses

Can i get some clarification on this please. what is the limiting factor/s this is based off and what are the huge losses
cheers

the inertial forces from reciprocation are proportionate to the square of the rpm
and, as with the combustion load producing friction from piston sideforce (this independent of rpm)
the inertia forces also produce friction force from piston sideforce (that increases as the square of rpm)

so some part of frictional power is proportionate to rpm, some proportionate to the square of rpm
and this part proportionate to the cube of rpm
(as is the pumping loss power)

add to these to any rpm-related combustion speed and inconsistency issues .....

[Brian Coat]

If you could throw more fuel chemistry and electronics at the combustion challenge and more materials/coatings/etc. solutions at friction and mechanical issues then at a fixed bore size, might good old intake gas speed end up being the show stopper/slower?

[PlatinumZealot]

Beryllium rods and Osmium bearings?

[Brian Coat]

I mean that mech./comb. constraints have more weapons you can throw at them than a constrained-size inlet valve diameter.

[PlatinumZealot]

Yes true.

Does anyone know what is the piston speed limit when you consider flame speed?

[gruntguru]

I don't think that is the primary relationship. Flame speed vs chamber dimensions and geometry determines how long it takes to get the mix burned and you need to get most of that done before say 30 deg ATDC.

[Edis]

With the 98 mm maximum bore I think it would have been difficult to run with significantly higher speeds. Higher speeds are only useful if you can produce more power, and to produce more power you need more air, and with the intake port sizes you can fit in a 98 mm bore you are probably on the limit of what the ports can flow at about 20 000 rpm.

Normally you need to achieve peak cylinder pressure about 15-20 degrees after top dead center, so the main combustion even needs to be done about then. But flame speed increase with turbulence, and turbulence increase with engine speed. The very large bore combined with the shape of the piston required for a reasonable compression ratio with a 39 or so mm stroke is hardly ideal for fast combustions though.