2014-2020 Formula One 1.6l V6 turbo engine formula

[olefud]

one last try here !

broadly speaking at 10500 rpm the engine has a designed boost and a (maximal) CR matched to this boost
the efficiency (of our lightly-compounded engine) is dominated by the CR
at 15000 rpm the cylinder contents will be 43% less so this CR is now much too low and will now cost engine efficiency ie power
(a lot more power than is available within the friction/rpm vs. supercharging work/rpm tradeoff)
at 15000 the engine is halfway to being N/A but the CR is not matched to this

whatever is done to somewhat alleviate this fundamental problem (I have made my suggestions)
the problem will surely be minimised (by minimising the speed range eg 10500-12300 is all we need)

Your point is taken –but there’s a pickable nit between compression ratio and compression pressure.

Compression ratio affords a fixed power and efficiency advantage as a function of the ∆ volume at full TDC compression vs. fully expanded volume at BDC. With a higher CR, the TDC pressure will be relatively higher independent of the fuel charge, i.e. a given part-throttle fuel charge will, upon combustion, exert a higher pressure on the piston, and greater but diminishing pressure will continue to exerted on the piston throughout the power stroke. This is solely VTDC/VBDC based.

On the other hand, stuffing more fuel charge into the cylinder will produce greater power and increase the TDC pressure for any given CR thus increasing power, but the mechanism is different. There is interplay between the CR and CP in that either mechanism can produce detonation pressures and either can be backed off to avoid detonation.

[chip engineer]

This could be a stupid idea. But I want to hear peoples thoughts on this.

The way the regulations work now you have max performance at 10500 rpm. And as TC says this rpm spot is likely where the CR is designed top be optimal. Revving the engine beyond 10500 rpm would need the boost to decrease to maintain A/F ratio. This means that from 10500 rpm to 15000 the powercurve should dip slightly because of increased inner friction and moving away from the CR sweet spot.

And here is the idea that might sound silly. But what if you bypassed the intercooler after 10500 rpm?? This would mean that the density of the air decreases which means that you can run more or the same boost maintaining the amount of air that you compress in the cylinder. This means that the total CR is maintained as the volume stays the same as at 10500 rpm. But the air holds less oxygen which makes it possible to keep the A/F ratio without decreasing the boost.

Hope you guys understand what I mean

I don't see how that changes anything about CR that would improve the ICE efficiency. It would just make the turbo compressor and piston compression work harder (against more pressure) and lower efficiency.

[chip engineer]

one last try here !

broadly speaking at 10500 rpm the engine has a designed boost and a (maximal) CR matched to this boost
the efficiency (of our lightly-compounded engine) is dominated by the CR
at 15000 rpm the cylinder contents will be 43% less so this CR is now much too low and will now cost engine efficiency ie power
(a lot more power than is available within the friction/rpm vs. supercharging work/rpm tradeoff)
at 15000 the engine is halfway to being N/A but the CR is not matched to this

whatever is done to somewhat alleviate this fundamental problem (I have made my suggestions)
the problem will surely be minimised (by minimising the speed range eg 10500-12300 is all we need)

That makes sense to me. Many pages back, someone suggested de-activiating some of the cylinders at high rpm. If withholding both fuel and air from some cylinders is allowed, it could extend the rpm range where the CR is optimum.

Under those conditions, the unused cylinders would also not be absorbing any combustion heat, further increasing efficiency.

Problem with de-activating cylinders is that they keep the friction without adding power.

But the friction from de-activated cylinders should be small if they are not working with much pressure, and the other cylinders should produce more power by using the fuel more efficiently. Some road cars use cylinder de-activation for better fuel economy under partial load (which somewhat equivalent to low boost high rpm here).

[wuzak]

But the friction from de-activated cylinders should be small if they are not working with much pressure, and the other cylinders should produce more power by using the fuel more efficiently. Some road cars use cylinder de-activation for better fuel economy under partial load (which somewhat equivalent to low boost high rpm here).

It is slightly different in road cars, as they are running at low power and small or closed throttle when the cylinder de-activation is working.

[Tommy Cookers]

........ between compression ratio and compression pressure.
There is interplay between the CR and CP in that either mechanism can produce detonation pressures and either can be backed off to avoid detonation.

what catches my attention is the extent to which the DI pressure allowed will enable a complex injection strategy that gives the highest CR and safely takes us closer than ever to detonation
managing combustion rate by managing injection rate/episodes, emulating a true (ie 'slow-speed'') Diesel but 100 times faster ??
presumably there will be some injection after the spark ? (done already in some production cars, or prototypes anyway ??)
for this DI cleverness 10500 rpm is much better than 15000

regarding gains in the combined ICE/MGUH power from 'backpressure running' raising combined efficiency ........
many NACA 1940s studies show (for sea level) substantial backpressure works well in engines with small (40deg) valve overlap
but with larger (76deg) overlap the efficiency gains stop at around parity of exhaust and inlet pressure
presumably exhaust valve closure is the significant factor
either way the gains are large
maybe F1 will close its exhaust valves earlier than in the 1920s ?

btw turbine power in 5-6 bar runs of earlier 80s F1 must have matched/exceeded our estimates for turbine power in 2014 ?

[olefud]

TC, it’s just speculation, but my take somewhat parallels yours. Overlap has been a two-edged sword in boosted engines –power or efficiency, take your choice. With greater but still moderate overlap, the intake pressure flows into the exhaust sweeping along the remnants of exhaust gases for greater power, lower efficiency. The boosted intake can supply more than adequate fuel mixture for power even with the loss of the exhaust-scavenging intake mixture. With little overlap, some exhaust remains in the cylinder decreasing power but enhancing efficiency.
In the new V6 there are two pregnant possibilities in this area. DI can be employed to provide an overall lean but locally rich fuel kernel at the ignition locus. This would provide initial stable combustion but would go lean as the flame front expanded. Follow on fuel injection, perhaps post ignition at least in part, would allow for an overall lean mixture with stable combustion. This would perhaps allow for a lean, highly compressed mixture that would suffer preignition if provided during the intake stroke, but which would be stable as a result of late introduction not allowing sufficient time for preignition.

Along with your suggestion of diminished overlap, it would be interesting to play with the powered turbine to have it driven by the exhaust during blow down and the strong portion of the exhaust stroke but morph into a powered impeller during the later portion of the exhaust stoke such that it scavenges the exhaust gases with minimal overlap, a “negatively boosted” exhaust as it were.

Or, with DI, you could keep the overlap and just run excess air from the turbo during overlap to scavenge prior to injecting fuel.

[dren]

Since it's fuel limited, you'd want the higher efficiency which would directly relate to more power, assuming you are running at the max limit fuel flow.

[WhiteBlue]

Incidentally, the formula is useful also for getting an idea of what changed with the passage from I4 to V6 and you'll easily see that the shorter stroke V6 with smaller/lighter pistons/con rods will have, at any given rpm, lower mechanical losses than the I4 would have had.

I think this formula is wrong because the I4 was going to produce less friction the the V6 will do. That much was commented by participanzts of the engine expert group when they were forced to accept the political compromize of the V6. Ferrari even wanted the fuel flow limit adjusted but the FiA remained determined to stick with the originally intended fuel limit. But the power will definitely be lower for the V6 than for the intended I4.

[langwadt]

Incidentally, the formula is useful also for getting an idea of what changed with the passage from I4 to V6 and you'll easily see that the shorter stroke V6 with smaller/lighter pistons/con rods will have, at any given rpm, lower mechanical losses than the I4 would have had.

I think this formula is wrong because the I4 was going to produce less friction the the V6 will do. That much was commented by participanzts of the engine expert group when they were forced to accept the political compromize of the V6. Ferrari even wanted the fuel flow limit adjusted but the FiA remained determined to stick with the originally intended fuel limit. But the power will definitely be lower for the V6 than for the intended I4.

I guess the line added to the spec "All six cylinders must be of equal capacity . " is there to make sure that V6 is really V6
though with the fixed bore there would not be much room to play games anyway

[Tommy Cookers]

Incidentally, the formula is useful also for getting an idea of what changed with the passage from I4 to V6 and you'll easily see that the shorter stroke V6 with smaller/lighter pistons/con rods will have, at any given rpm, lower mechanical losses than the I4 would have had.

I think this formula is wrong because the I4 was going to produce less friction the the V6 will do.
...... But the power will definitely be lower for the V6 than for the intended I4.

so would a 3 cylinder engine be more powerful than the 4 ?
and a twin be more powerful again ?
(IIRC such were banned in 87 or 88 when turbo F1 rules had introduced significant limits of fuel quantity)

the conventional view is the smaller the cylinders the higher the useable CR
and the V6 will have 4 main bearings, the I4 would surely have and need 5 main bearings at these rpm

the (V6) friction will only be about 10% if they have designed for 10500 rpm not 15000

[langwadt]

Incidentally, the formula is useful also for getting an idea of what changed with the passage from I4 to V6 and you'll easily see that the shorter stroke V6 with smaller/lighter pistons/con rods will have, at any given rpm, lower mechanical losses than the I4 would have had.

I think this formula is wrong because the I4 was going to produce less friction the the V6 will do.
...... But the power will definitely be lower for the V6 than for the intended I4.

so would a 3 cylinder engine be more powerful than the 4 ?
and a twin be more powerful again ?
(IIRC such were banned in 87 or 88 when turbo F1 rules had introduced significant limits of fuel quantity)

the conventional view is the smaller the cylinders the higher the useable CR

the friction will only be about 10% if they have designed for 10500 rpm not 15000

Imagine the cry from Ferrari if they had to build a twin to be competitive

it really doesn't matter, the way the rules are written with pretty much every measurement and material mandated
they might as well just have one engine factory and the teams can then choose what name they want to put on
valve cover, the stuff around the engine might vary a bit in the details but most of it bought from outside
that leaves the software which is part of the spec ecu and tightly controlled by FIA

so apart from cheating what is there to make the big difference ?

I sure in the beginning a few of the engines will expire in a plume of smoke, but after that is back to playing with CF
and windtunnels

[Holm86]

This could be a stupid idea. But I want to hear peoples thoughts on this.

The way the regulations work now you have max performance at 10500 rpm. And as TC says this rpm spot is likely where the CR is designed top be optimal. Revving the engine beyond 10500 rpm would need the boost to decrease to maintain A/F ratio. This means that from 10500 rpm to 15000 the powercurve should dip slightly because of increased inner friction and moving away from the CR sweet spot.

And here is the idea that might sound silly. But what if you bypassed the intercooler after 10500 rpm?? This would mean that the density of the air decreases which means that you can run more or the same boost maintaining the amount of air that you compress in the cylinder. This means that the total CR is maintained as the volume stays the same as at 10500 rpm. But the air holds less oxygen which makes it possible to keep the A/F ratio without decreasing the boost.

Hope you guys understand what I mean

I don't see how that changes anything about CR that would improve the ICE efficiency. It would just make the turbo compressor and piston compression work harder (against more pressure) and lower efficiency.

It changes nothing about the static CR no. But it creates a higher pressure at the end of the compression stroke. Which is what you want. That's why you raise CR as much as possible. You want that pressure to be as high as mechanically possible and as high as possible without knock. That increases the thermal efficiency. I don't know why it should be a problem for the turbo. And again I don't see why more piston compression work would decrease ICE efficiency. Otherwise there would be now reason in increasing CR to begin with.

[chip engineer]

This could be a stupid idea. But I want to hear peoples thoughts on this.

The way the regulations work now you have max performance at 10500 rpm. And as TC says this rpm spot is likely where the CR is designed top be optimal. Revving the engine beyond 10500 rpm would need the boost to decrease to maintain A/F ratio. This means that from 10500 rpm to 15000 the powercurve should dip slightly because of increased inner friction and moving away from the CR sweet spot.

And here is the idea that might sound silly. But what if you bypassed the intercooler after 10500 rpm?? This would mean that the density of the air decreases which means that you can run more or the same boost maintaining the amount of air that you compress in the cylinder. This means that the total CR is maintained as the volume stays the same as at 10500 rpm. But the air holds less oxygen which makes it possible to keep the A/F ratio without decreasing the boost.

Hope you guys understand what I mean

I don't see how that changes anything about CR that would improve the ICE efficiency. It would just make the turbo compressor and piston compression work harder (against more pressure) and lower efficiency.

It changes nothing about the static CR no. But it creates a higher pressure at the end of the compression stroke. Which is what you want. That's why you raise CR as much as possible. You want that pressure to be as high as mechanically possible and as high as possible without knock. That increases the thermal efficiency. I don't know why it should be a problem for the turbo. And again I don't see why more piston compression work would decrease ICE efficiency. Otherwise there would be now reason in increasing CR to begin with.

It is really the expansion ratio, not compression ratio, that matters for efficiency. That is why the Atkinson cycle ICE in the Prius is relatively efficient. Pressure at the end of the compression stroke is not increased in the Atkinson cycle over a standard engine. Instead, pressure is reduced at the end of the expansion stroke.

[Tommy Cookers]

Holm's idea seems to me quite useful (in this fixed CR/ER, no VVT engine)
efficiency is in real engines directly but not exactly related to CR/ER

charge cooling is there to prevent detonation or knocking at chosen charge mass and CR
it also reduces supercharging work, we might choose to sacrifice some of this (in having charge cooling only when vital)
at higher rpm our uncooled but still lesser charge mass will be safe despite the higher temperatures throughout the in-cylinder cycle
these will include a higher peak to the cycle despite our geometric CR being unchanged
the overall efficiency of this altered cycle will surely be an improvement ?
(also it may be better matched to the 'on design' timing of exhaust valve closure)
the exhaust would be more energetic on blowdown, allowing somewhat more turbine recovery

but can the intercooler be smaller this way ?

[Reca]

broadly speaking at 10500 rpm the engine has a designed boost and a (maximal) CR matched to this boost

They can design for max CR at higher rpm, should they find revving higher beneficial for total power, at lower rpm they would just not exploit the full fuel rate due to reduced boost.
With correct gearing (even if fixed for all championship 8 gears are good enough for it) it's possible to have, in the WOT power limited areas, the engine revving in a range 2k rpm wide or little more, and when out of that range car is in grip limited areas of lap where it's not necessary to use the full fuel rate anyway.

Without sure data we shouldn't exclude the possibility that they could optimize for a 2k or so rpm range, anywhere in the max fuel rate band (which is potentially 4.5k rpm wide), could be 10.5-12.5k as you say, or shifted 1-1.5k rpm higher, potentially up to 13k-15k (albeit unlikely), it all depends by what they find convenient for global performance.

I think this formula is wrong because the I4 was going to produce less friction the the V6 will do. That much was commented by participanzts of the engine expert group when they were forced to accept the political compromize of the V6. Ferrari even wanted the fuel flow limit adjusted but the FiA remained determined to stick with the originally intended fuel limit. But the power will definitely be lower for the V6 than for the intended I4.

That formula is not wrong (...) and it's not the only hint in the direction that V6 has lower mechanical losses (at any given rpm) than an I4; it just confirms, with an easy to see summarization, a general result explained for the several pages of that book devoted to friction and mechanical losses in general, but that you can find in various other sources/papers on the argument: when it comes to mechanical losses for a high speed engine, going for more cylinders reduces them.
It's a fundamental aspect of decades of design, goes well beyond the interpretation of a single formula, if you do an analysis of the various elements that favorably change by splitting the same displacement in more cylinders (reductions of masses and travelled distances thus velocities and accelerations of the moving parts...) you should see it by yourself. If not, take a good book on high speed engines design and learn it there.

Probably the "participants" that you heard commenting weren't technicians and/or took a convenient opportunity to push their own agenda exploiting a non technical audience by being "economical with truth" (never happens, right?).
Alternative is that you simply misremember/misunderstood the comment.
If the comparison between the formats for example was made comparing max allowed rpm, thus a V6 revving at 15k vs a I4 revving at 12k, in that case losses for the V6 can indeed be higher because the added 3k rpm cancel the advantage.
That isn't a fair comparison though, as with the fuel rate rule nobody forces, or expects, the V6 to go all the way up to 15k (unless they find it beneficial, which would make of the higher losses a moot point as it's end result that matters); with the I4 on the other hand having to go up to 12k would have been a requirement to exploit the fuel rate.
If the V6 will rev in the same range that the I4 would have seen or even a bit higher, the mechanical losses will be lower, there's no doubt about that.

As for the "political compromises" in the EWG, let's just avoid going there, you have your own ideas about which way it was politically driven that you made clear multiple times, and that are largely based on your opinion about Ferrari, I have others (and not only because I'm Ferrarista), we would never reach an agreement and I've certainly better things to do that being involved in a silly argument like that one. Besides, it's way off topic here.