F1technical.net

Brian Coat wrote:

stevesingo wrote:With the ability to create void spaces within the structure, would it be feasible to use sodium filled voids for cooling similar to exhaust valves?

Good thinking.

Yes.

That is an active research area.

http://www.bine.info/fileadmin/content/ ... x_engl.pdf

While perfectly fine in a slow moving diesel engine, would this work on an engine with much higher mean piston speed? I would imagine that it could lead to a harmonics nightmare.

well it works in valves, these have high accelerations and historically were driven by mechanisms that might seem vulnerable to any such 'rogue' effects
and the research is aimed at modern and new high specific output engines

Question out of sheer curiosity do liquid metal filled valves have a "deadblow" effect when they seat? Your comment made me think about this tangent.

fwiw my guess is the fluid metal viscosity is very small and so there is little damping/heating effect ie energy absorbed in any churning with piston motion

FERRARI 2017 - PART 4: The Power Unit 2017 is an evolution of the 2016

http://www.f1analisitecnica.com/2017/02 ... -2017.html

http://www.f1analisitecnica.com/2017/02 ... -2017.html

- energy recovery from MGU-K will be less than in 2016 because of shorter braking time, therefore MGU-H will become more important
- turbine and compressor will be redesigned from 2016 but kept together, not split as in Mercedes engine
- no big changes on the ICE, just optimization of the HCCI
- target for Australia: peak power > 1000 CV (already reached at the bench, but with teething problems)
- 3 new addictive manufacturing machines arrived in Maranello, currently under calibration
- not worried about the power unit, but they are worried about the chassis/aero because of the delay piled up in the first part of 2016, they tried to make up ground in the last 6 months thanks to huge work from Rory Byrne (hopefully haste will not make waste)

So, they have got the excuse ready and that's worrying news.

Silent Storm wrote:http://www.f1analisitecnica.com/2017/02 ... -2017.html

- energy recovery from MGU-K will be less than in 2016 because of shorter braking time, therefore MGU-H will become more important
- turbine and compressor will be redesigned from 2016 but kept together, not split as in Mercedes engine
- no big changes on the ICE, just optimization of the HCCI
- target for Australia: peak power > 1000 CV (already reached at the bench, but with teething problems)
- 3 new addictive manufacturing machines arrived in Maranello, currently under calibration
- not worried about the power unit, but they are worried about the chassis/aero because of the delay piled up in the first part of 2016, they tried to make up ground in the last 6 months thanks to huge work from Rory Byrne (hopefully haste will not make waste)

So, they have got the excuse ready and that's worrying news.

So Ferrari being worried about having to make up ground is an excuse? SMH Ferrari isnt dominating the sport so where does all this negativity come from i wonder?

Tommy Cookers wrote:

gruntguru wrote: - Rate of heat transfer is a function of thermal conductivity but also thinness of the section. Thinner crown = faster heat flow.

surely heat flow will be faster with a thicker section ? ..... (eg consider electrical conduction, or why steel wool burns)
this is part of the reason why Al alloy gives much lower crown temperature

and the coefficient of thermal expansion will be much lower with steel - potentially useful to the designer

In the case of a piston crown the heat is transferring across the section (to the cooling oil) ie the thickness of the crown is the length of the heat flow path. This wuld be preferable to the transverse path via the ring pack.

@ Tommy

You said thicker section...

The cross sectional area of the crown would be the same whether thin or thick..

So the thinner crown will have less resistance to heat flow.

Like a thin walled heat exchanger.

Think of short cables of given cross section versus miles of cable of the same.

fwiw I have been assuming that most of the heat flow is still 'SI-traditional' (ie conduction laterally to cylinder walls)
as (I assume) applies in the modern SI engines that have some piston oil-cooling eg by under-crown oil jet or spray
(this eg in road motorcycles allowing thinner crowns and walls etc, and so lighter pistons and more rpm and power)

if most heat flow is by under-crown heat exchange to moving fluid surely crown thickness is trivial compared to other practical issues

Tommy Cookers wrote:if most heat flow is by under-crown heat exchange to moving fluid surely crown thickness is trivial compared to other practical issues

Probably.

I would assume all of these use some sort of oil jetting to cool the piston/cylinder walls.

Here's a question: How much does the combustion chamber design drive heat transfer before the exhaust exists the EV? Are coatings used to resist the transfer, or are other means utilized?

Spraying oil onto the underside of a race-type piston crown is not an efficient method of cooling. The problem is the very brief period of time the oil spends in contact with the crown surface, which limits the heat transfer/temperature rise produced in the cooling oil mass flow. The cooling is sprayed on and then is immediately slung off.

Automotive pistons designed for oil cooling, like turbo-diesel engine pistons, have galleries under the crown that collect the cooling oil spray and keep it in contact with the crown surfaces for a much longer period of time, significantly increasing heat transfer to the oil.

riff_raff wrote:Spraying oil onto the underside of a race-type piston crown is not an efficient method of cooling. The problem is the very brief period of time the oil spends in contact with the crown surface, which limits the heat transfer/temperature rise produced in the cooling oil mass flow. The cooling is sprayed on and then is immediately slung off.

Automotive pistons designed for oil cooling, like turbo-diesel engine pistons, have galleries under the crown that collect the cooling oil spray and keep it in contact with the crown surfaces for a much longer period of time, significantly increasing heat transfer to the oil.

Of course, you are right.

As discussed on here before and as used in F1 before (last turbo era).

I think the sodium cooling R&D is aimed at pistons which currently use a piston oil gallery.

Silent Storm wrote:http://www.f1analisitecnica.com/2017/02 ... -2017.html

- energy recovery from MGU-K will be less than in 2016 because of shorter braking time, therefore MGU-H will become more important

I don't get it. The braking time will be reduced but the braking power will increase as the total braking energy will remain unchanged or even increase because of higher speeds and larger weight.