Ferrari Power Unit Hardware & Software

[PhillipM]

A big part of this too might be lubrication & oil cooling. Pourous or channeled interiors in the piston & conrod could connect the various oil passages, allowing oil to be conveyed directly to the piston head. A continuous flow of pressurized oil through the piston seems like it would be ideal for keeping the crown cool, compared to what could be achieved through oil jets alone.

There's also an intriguing possibility of creating a second prechamber under the crown with jet passages out of it to mirror what is in the head, tricky to inject into though...

[taperoo2k]

That a process is industrial or not doesn't really tell us about the qualities of the end product. 'Industrial' usually only refers to activities associated with manufacturing products. From pistons to marshmallows. Both industrial products, but not interchangeable.

I was being lazy and not using the correct term for what Ferrari might be using for it's piston manufacture -
Direct Metal Laser Sintering. If you've watched the first video you'll have the seen the quality control processes. If Ferrari are using this process they will be testing the pistons rigorously before they even go near a race track.

I'm not a turbine expert but I think even in that example the demands are quite different to a piston working against pressures of 400+ bar. A turbine blade may operate within similar high temps & pressures, but it is not subjected to the same sort of shocks & loads that a piston sees. Perhaps someone else can explain this more eloquently than I can...

The demands are different but no less extreme. Suffice to say Turbine blades will deform when exposed to repeated high temperatures leading to reduction in performance and eventual failure, which is why they are coated in various materials to reduce the problem, otherwise known as Creep in materials science. They also suffer from resonance issues from what I remember from materials science at the further education college I went to (not university level by any means).
What DMLS offers Ferrari is the ability to precisely build structures into a piston you may not otherwise be able to achieve without specialised tooling. Also means the manufacturing times are reduced, so Ferrari could probably test a piston, discover problems, come up with solutions, redesign the Piston and have a new one ready to test faster than they otherwise normally would. It also means they can likely use materials like steel, as they can fine tune the weight.

[gruntguru]

Clearly the advantage is thermal - aluminium softens at fairly low temperatures and they want to operate with a hotter piston crown.

Peak combustion temperatures and pressures are very high in these engines and one path to higher TE (power) is higher pressure and temperature hence the search for increased temperature tolerance at the piston crown. Steel is great but its strength/mass ratio works against it - especially in thin sections under pressure loading like the piston crown. Honeycombed steel allows the crown to be thicker (resisting bending) without the extra weight.

If they can make a steel piston with the same mass and strength as an aluminium piston there will be a huge advantage in temperature tolerance.

[godlameroso]

Heck, just having a ring land that's less prone to cracking, like in aluminum pistons would be a game changer. I wonder what a steel piston skirt would require as far as cylinder coating.

[Craigy]

Heck, just having a ring land that's less prone to cracking, like in aluminum pistons would be a game changer. I wonder what a steel piston skirt would require as far as cylinder coating.

Probably DLC like the rest of the cylinder.

[ripper]

In the article there's another important piece:

Il motore che verrà montato inizialmente sulla nuova Rossa concepita per le regole 2017 sarà una versione molto tradizionale, in attesa che dal reparto che ha Lorenzo Sassi il capo progettista e Enrico Gualtieri il responsabile dell’assemblaggio, arrivino importanti novità che dovrebbero permettere un grosso salto prestazionale alla power unit che alla fine non avrà niente in comune con l’unità che è stata usata nel 2016.

The engine that at the beginning will be mounted on the new 2017 car will be very traditional version, while waiting that from that from the PU division will arrive important new parts that should bring a big prestational jump to the PU that, at the end, will have nothing in common with the one used in 2016.


So, if what the article says is true, Ferrari should start with a traditional&safe PU and bring more changes during the season.

[Tommy Cookers]

Clearly the advantage is thermal - aluminium softens at fairly low temperatures and they want to operate with a hotter piston crown.
Peak combustion temperatures and pressures are very high in these engines and one path to higher TE (power) is higher pressure and temperature hence the search for increased temperature tolerance at the piston crown. Steel is great but its strength/mass ratio works against it - especially in thin sections under pressure loading like the piston crown. Honeycombed steel allows the crown to be thicker (resisting bending) without the extra weight.
If they can make a steel piston with the same mass and strength as an aluminium piston there will be a huge advantage in temperature tolerance.

steel or part-steel was predicted by Gilles Simon of P.U.R.E.
with the rather modest rpm and stroke combination dictated by the rules a somewhat heavier piston than usual seems to have no real disbenefit

the prime reason for replacement by Al alloy (of steel pistons ie in performance engines) was lower crown temperature rather than slightly lower weight
Al's far thicker crown etc and far greater thermal conductivity giving much lower crown temperature
lower crown temperature allowing higher CR and so more power and efficiency - eg in UK aviation during WW1 (after Bentley's racecar use pre WW1)
Heron made the UK small car Hotchkiss V twin have Al pistons in 1921 (as essential in an aircooled engine) and Al was general by eg 1926 Austin 20/6

the F1 engine has per cycle multiple small episodes of DI
presumably better able to manage/contain detonation despite the higher crown temperatures
also maybe the tailored fuel helps here

a good read (thanks due to Mr Taulbut) .....
http://www.grandprixengines.co.uk/Note_14.pdf

[wuzak]

Sounds awesome but can such a 3d printed piston withstand the incredible forces and temperatures of an F1 engine?

A minimum weight would not preclude optimising the strength or durability of the piston, nor its weight distribution. Given vernacular, I can't be sure if they mean piston head or connecting rod when they say "piston."

I agree with you though, durability does seem like an issue. These are usually machined or forged parts. A purely 3D printed part seems unlikely, but a hybrid seems feasible—3D print the core, then bond it to a machined or forged skirt and cap. Same would go for a conrod.

The advantage of 3d printing is to put material precisely where it is needed and none where it is not.

Plus they can do clever things which cannot be done by forging/casting and machining, like making honeycomb support structures.

I can't see the advantage in making a hybrid. There is an additional joining process that could fail.

In any case, the 3d printed piston may still have parts machined, such as the gudgeon pin bore and the outside diameter.

[roon]

It's true. Steel melts at higher temps than aluminum. And 3D printing is an interesting process that permits freedom of form. But I maintain: what are the mechanical properties of a SLS part? This is the root of my doubt/confusion. It's essentially one big, well-formed weld. How does this compare to a forged part, or a machined part? Can anyone comment or speculate on the strength of a piston made from 300g of sintered steel?

wuzak- Regarding hybrid materials, I was thinking along the same lines of familiar honeycomb/foam core composites. (I mean composites in the sense of dissimilar material combination, not just CFRP.) Bridge two skins of high tensile strenth material with a lightweight core. The advantage is only if my assumptions about a sintered part's durability are correct. You raise a good point about secondary maching that I think a lot of people gloss over when they think about 3D printing. There is a resolution limit to it. As such, I image the turnaround time for a printed part, in this scenario, is similar to or slower than a comparable machined part. In certain contexts "rapid prototyping" simply becomes "prototyping."

[PlatinumZealot]

Clearly the advantage is thermal - aluminium softens at fairly low temperatures and they want to operate with a hotter piston crown.

Peak combustion temperatures and pressures are very high in these engines and one path to higher TE (power) is higher pressure and temperature hence the search for increased temperature tolerance at the piston crown. Steel is great but its strength/mass ratio works against it - especially in thin sections under pressure loading like the piston crown. Honeycombed steel allows the crown to be thicker (resisting bending) without the extra weight.

If they can make a steel piston with the same mass and strength as an aluminium piston there will be a huge advantage in temperature tolerance.

Guru, there is a nice thread on steel pistons about the place. An article was posted there about steel pistons for Moto GP. The piston was lighter and stronger than aluminum counterparts, and tiny oil galleries were even made under the crown. There was one major problem though. The poorer heat dissipation and higher temperatures near the edge of the piston crown has a tendency to bake the oil to the rings which leads to a risk of siezure. So i guess this is the problem the engineers are working on fixing now. Getting a good heat dissipation in such a small mass of material having much lower thermal conductivity. I can't see it happening without significant cooling by something else other than oil though. It will be really interesting how engineers solve it.

[PlatinumZealot]

3D printing does not produce the necessary forces to strengthen steel.

We all know forging is the strongest way. It is all about crystal and grain boundaires and precipating the right elements at thos boundaries. Not to mention grain alignment. Forging is the way.
And regular old printed and sintered steel won't achieve that.

Whoever said the thing about combining a forged peice with a 3D honeycomb structure i think you have a good sense of how materials work. Though to be honest, I think the article is sensationalism clickbait and I don't think 3D honeycomb thingamajigs are necessary to achieve light weight in a piston. It is a piston! An f1 piston looks like a pancake with some yokes underneath to push the wrist pins through! Nothing complex in the shape for you to whip out the 3D printer. If you want to make it light, simply machine the underside like a waffle slab. Light weight achieved.

However if you are thinking duh george, hey! what about heat transfer?! If you 3D print a honeycomb . . which is filled with air... AIR!! Which is a poor conductor for heat. You are asking for trouble.
Better you had said print some stratified aluminum steel intermeshing network and drop forge the whole damn thing then machine it to achieve the final shape to achieve a good middlegroud.
Cool oil rings, piston skirts and a strong crown achieved. Crazy stuff but probably more sound that talk of honeycomb pistons.

[rgava]

I've professional experience with steel sintered parts in toolmaking industry (for plastic injection moulds components).
The resulting part has approximately 80% of the toughness of the same steel forged, same hardness, can be post-machined where necessary.
Besides what some of you are pointing out about the heat dissipation I see no big problems on using this technology to manufacture pistons for F1 engines.
On the other side, I understood and read on this and other engine related threads that lean combustion leads to lower temperature, lower heat transferred to the cylinder walls, piston crown and head. Correct me if i'm wrong.

[Brian Coat]

How interesting.

A few random thoughts ...


1)Just for general interest
https://www.google.com/patents/US20140299091
http://papers.sae.org/2015-01-0505/

2) The days of not being able to achieve ~as-forged properties with AM Are behind us. e.g. EBM+HIP+HT

3) Fred Turk (Mahle Racing Pistons) has hinted at steel F1 pistons for some time.

4) Is low heat transfer always a bad thing?

5) Not that they are needed but the aero materials available are way ahead of anything F1 needs. The temperature/stress demands in a GT are much higher. The comments about the impulsive nature of the F1 load cycle are correct but stresses are still low and the same cycle provides a lot of cooling to the piston (fresh charge). Perspective: Atmo era pistons used 80 year old aero alloys ... and aero alloys developed a lot in 80 years.

[shady]

It's true. Steel melts at higher temps than aluminum. And 3D printing is an interesting process that permits freedom of form. But I maintain: what are the mechanical properties of a SLS part? This is the root of my doubt/confusion. It's essentially one big, well-formed weld. How does this compare to a forged part, or a machined part? Can anyone comment or speculate on the strength of a piston made from 300g of sintered steel?

wuzak- Regarding hybrid materials, I was thinking along the same lines of familiar honeycomb/foam core composites. (I mean composites in the sense of dissimilar material combination, not just CFRP.) Bridge two skins of high tensile strenth material with a lightweight core. The advantage is only if my assumptions about a sintered part's durability are correct. You raise a good point about secondary maching that I think a lot of people gloss over when they think about 3D printing. There is a resolution limit to it. As such, I image the turnaround time for a printed part, in this scenario, is similar to or slower than a comparable machined part. In certain contexts "rapid prototyping" simply becomes "prototyping."

Along with the other links to Piston Crowns being additively manufactured, NASA has tested SLS injectors for use in their rockets http://www.space.com/27487-nasa-3d-prin ... video.html

I dont think an F1 piston is a more stressful environment than whats needed to feed a rocket engine assembly, given the variety of environments these parts have to operate in.

[Craigy]

I dont think an F1 piston is a more stressful environment than whats needed to feed a rocket engine assembly, given the variety of environments these parts have to operate in.

These are radically different environments - the piston is getting near the upper thermal limits of the material.
Certainly on western rockets, the rocket injector will typically be at very cold temperatures (because it's typically injecting liquid hydrogen) - somewhere between 90Kelvin and 28Kelvin. The materials will be very brittle in that sort of environment.

On certain oxygen-cycle (mainly Russian/soviet) rockets [eg. NK-33 and RD170 family], the materials have to be much, much tougher because the oxygen-rich preburner mix (lox/kerosene) is very corrosive at the temperatures involved there; circa 400C at 300bar. For those rockets, the materials are a tough high-temp type of high chromium content stainless created for the application, to avoid burn-through accidents.