2014-2020 Formula One 1.6l V6 turbo engine formula

[R_GoWin]

What about that?https://twitter.com/f1talks/status/724184648113377280

According to this article Mahle confirmed in their annual report (published two days ago) that TJI was introduced in Scuderia Ferrari engine.

I would question the authenticity of the source as if you see the image on the twitter feed and article in Polish - it clearly shows a Mahle TJI and says 97% of fuel in main chamber is provided by port fuel injection - which is not allowed in F1.

[R_GoWin]

Mahle's Ferarri F1 "Jet Ignition" PR mentions only "special surface ignition".

The word "spark" doesn't appear.

The word "ignition" only appears as part of the phrase "special surface ignition". http://www.us.mahle.com/mahle_north_ame ... y-life.jsp

What "special surface" does Mahle use to ignite the charge?

That's a pretty interesting link. A while ago, I came across a pre-chamber design for a gas engine which used a lining of 'resistive heating material' on the side walls of the pre-chamber. While Mahle's PR machine has tried to leverage their association with F1 to push the Turbulent Jet Ignition (prechamber+spark plug+DI) for the gasoline market - it could be that they have used a design which is inspired by it - using a resistive heating on the walls of pre-chamber to create the turbulent jets.

Flame kernel development is well pronounced using spark plugs, but I've got no idea how a resistive heating system could initiate the ionisation, break down and arc development during ignition. I would think of it as more of a low energy - long duration glow. Thinking out aloud - I guess it could be all the energy that HCCI would need inside the pre-chamber.

[R_GoWin]

......For clarity purposes, what Mr. Hughes described isn't HCCI, (though he labels it as HCCI).

1. Compression ignition occurs in the richer pre-chamber.
2. The pre-chamber then ignites the leaner main chamber.
3. Two different A/F mixtures (by definition) aren't homogeneous.

Not sure what the correct term would be to describe this compression ignition system, but for clarity it seems inappropriate to describe it as HCCI.

imo (and having at first had the same view as yours) ....
the convention among researchers seems to regard it as HCCI
presumably because the main charge exists before being ignited ie the opposite of the usual CI injection coinciding with combustion

I've mentioned this once earlier as well - HCCI does look like a misnomer. Infact, stratification - temperature and composition - is a known strategy to help with controlling auto-ingition and raising the load. It could be anywhere between Stratified Charge Compression Ignition (SCCI) or Pre-mixed charge compression ingition (PCCI) or Optimised Kinetics Process (OKP) or Controlled Autio-ignition (CAI). There are no shortages of acronyms in the automotive world eh?! But hey what's in a name!

http://digbib.ubka.uni-karlsruhe.de/vol ... nts/762475

You would imagine Controlled Auto-ignition (CAI) to be a catch all phrase, but:

Although usage still varies widely among the relevant organisations, a recent consensus
seems to have emerged concerning the application of the terms CAI and HCCI for
gasoline engines. CAI is used to describe residual-promoted auto-ignition with a
stoichiometric or near-stoichiometric air-fuel mixture. CAI engine specifications are
very similar to those of the conventional spark-ignited gasoline engine, with the
important exception of the valvetrain used. The term HCCI is then reserved for engines
where auto-ignition of the gasoline-air charge results from a high compression ratio,
intake air heating, or a combination of the two. Very lean mixtures are used to control
rate of heat release in the HCCI engine.

[R_GoWin]

So it seems Ferrari is using Honeywell for their compressors and turbines.

https://turbo.honeywell.com/whats-new-i ... formula-1/

2 things were stated here, not sure if you can derive much information from either:
1. “When you consider that exhaust gas temperatures approach the temperature of lava, and internal tip speeds for the turbo’s turbine wheel are approaching 600 meters per second, you begin to see the challenges for bringing durability and performance together,” said Craig Balis, vice president and chief technology officer for Honeywell Transportation Systems.
2. "In general, for each percentage point of efficiency gain by the turbine and the compressor wheels, the engine can produce 2kW and 1kW of more power respectively."

Note I'll also post this in the Ferrari PU thread.

Totally not related, but did anyone else find it an odd comparison? Exhaust gas to lava! Is that even meant to magnify the challenges of durability of turbo chargers? LAVA of all the things
Every kid doing science in school knows why steam at 100degC is more dangerous than water at 100degC. I do not know much geology, but clearly the hot molten rocks in liquid state have gone past the latent heat of melting and carry more energy!

[Edis]

If the MGU-H is loaded, would this not increase internal EGR due to increased back pressure.

Turbine speed doesn't really influence the back pressure that much, to influence back pressure you probably need a variable nozzle turbine, which is used to control EGR in many diesels, but that isn't allowed in F1.

Mahle's Ferarri F1 "Jet Ignition" PR mentions only "special surface ignition".

The word "spark" doesn't appear.

The word "ignition" only appears as part of the phrase "special surface ignition". http://www.us.mahle.com/mahle_north_ame ... y-life.jsp

What "special surface" does Mahle use to ignite the charge?

I think they simply refer to distributed ignition sites with jet ignition as opposed to a single point of ignition with regular spark ignition. As press releases are often written by PR people, I wouldn't read too much into the exact words used, read between the lines instead. How Mahle Jet Ignition works is well described elsewhere.

So there is no HCCI nor CI, if I understand the polish article well. But can we really disclose CI definitely (an f1 angine that works a bit like an indirect injection diesel engine at certain loads)?
The Mahle quotes are a bit vague indeed...

I think we can exclude compression ignition, the HCCI description is probably based on a misunderstanding as most reporters in F1 have no in-depht knowledge of combustion engines . If someone describe a system that allows distributed ignition sites and fast combustion similar to an HCCI engine, I think there is a great chance the system will be described as HCCI even though it isn't.

I think the press releases by Mahle are clear enough, what they are using is some form spark plug initiated jet ignition system with a pre-chamber (as 5.11 only permit spark plugs for ignition ) similar to Mahle Jet Ignition.

[FW17]

What about that?https://twitter.com/f1talks/status/724184648113377280

According to this article Mahle confirmed in their annual report (published two days ago) that TJI was introduced in Scuderia Ferrari engine.

I would question the authenticity of the source as if you see the image on the twitter feed and article in Polish - it clearly shows a Mahle TJI and says 97% of fuel in main chamber is provided by port fuel injection - which is not allowed in F1.

Why would it be difficult for an injector to inject 97% of fuel in the cylinder and 3% in the prechamber?

Once the idea is formulated engineers more often than not get to the solution. With large teams working, it is all the more faster

[Edis]

Jet ignition confirmed for Ferrari, and Andy Cowell says Mercedes are not using HCCI.

http://www.motorsportmagazine.com/f1/fe ... -ignition/

[NL_Fer]

Probably with one DI allowed, they fuel 97% during the intake, as the piston goes down. And the 3% during compression, just before ignition. Using some swirl technologies they can fix that i guess.

But so Ferrari has Jet Ignition confirmed, what is Mercedes been using? Because they are working on their Diesotto prototype for over 10 years now. Maybe they have an autoignition gasoline engine ready, but without the sought after HCCI exhaust NOx and soot levels (really low)

Maybe they are using some usable modes from Diesotto, the ones with high thermal efficiency at high loads.

[ringo]

Jet ignition confirmed for Ferrari, and Andy Cowell says Mercedes are not using HCCI.

http://www.motorsportmagazine.com/f1/fe ... -ignition/

Yep, i'm not why some were pushing HCCI, when there was zero evidence of it being used. From the horse's Mouth (Mahle) TJI has been stated as the technology used and people were still ignoring it in preference for HCCI which isn't applicable to a race engine.

[Tommy Cookers]

most believe the cars use 3 bar or more MAP at full power - implying an AFR implausibly lean for speedy and consistent SI combustion ?
but TJI has maybe enabled raising lamda to 1.7, increased boost and air massflow yielding a reduced mean cycle temperature ......

mainly ? benefiting efficiency via reduced heat heat loss to coolant etc and to exhaust (reduced entropy but retention of turbine-useable energy)
(this also a highlight of HCCI and PPC and SA modes)
and, raising useable CR and improved ratio of specific heats within cycle

over 3 years we all failed to predict what now seems to be the main benefit (of more boosted and leaner running)

[gruntguru]

Checking my notes A/F 12.8 max. power on a 14.5 stoich race fuel.
I'm hoping they will be able to take something like the "Mahle" DI pre-chamber gasoline jet ignition to the next level.

First suggested by pgfpro 4 years ago. http://www.f1technical.net/forum/viewto ... 70#p365070

[pgfpro]

Checking my notes A/F 12.8 max. power on a 14.5 stoich race fuel.
I'm hoping they will be able to take something like the "Mahle" DI pre-chamber gasoline jet ignition to the next level.

First suggested by pgfpro 4 years ago. http://www.f1technical.net/forum/viewto ... 70#p365070

Thanks gruntguru!!!!
I was working out some bugs on my own lean burn pre-chamber system back in 2011 and starting researching who else at that time was building something along the same lines. This is when I came across the Mahle system and started thinking it could work very well in the new F1 type power unit? Lucky guess on my part

[PlatinumZealot]

What about that?

http://www.f1talks.pl/2016/04/24/techno ... ch-ferrari

According to this article Mahle confirmed in their annual report (published two days ago) that TJI was introduced in Scuderia Ferrari engine.

I too am believing that Jet ignition is used instead. This article seems to confirm it. HCCI has issues with intake air temperature control and high precision combustion especially since EGR is difficult in F1 and the high engine speeds, but JI on the other hand excels at rapid combustion - a better match for F1. Jet ignition seem to have a pseudo HCCI effect too. It is not homogeneous combustion but when those five jets of hot fire shoot out across the chamber they "jet" across the chamber fast than any flame front can do - this was hinted at in the Mahle article. Because the jets reach the outside of the chamber so quickly, the main chamber ignition happens right across the radius of the chamber propagating from those radial "jet lines" almost at the same time. Also why the Mahle article also stressed the importance of the orifices in the nozzle. It is very important to impart speed and turbulence. The jet has to move extremely fast across the combustion chamber for it to work.

[PlatinumZealot]

Probably with one DI allowed, they fuel 97% during the intake, as the piston goes down. And the 3% during compression, just before ignition. Using some swirl technologies they can fix that i guess.

But so Ferrari has Jet Ignition confirmed, what is Mercedes been using? Because they are working on their Diesotto prototype for over 10 years now. Maybe they have an autoignition gasoline engine ready, but without the sought after HCCI exhaust NOx and soot levels (really low)

Maybe they are using some usable modes from Diesotto, the ones with high thermal efficiency at high loads.

They could be using the same technology but from a different maker. A user posted a video of the MAN engine with the JET ignition, only it was Natural gas. It looks extremely similar to the mahle concept, which leads me to believe that this JI is something that is widely known about in the engine design realm.

[bill shoe]

Not understanding something here.

From Steven's article here on F1T--

The jet igniter itself includes a small ignition chamber with a direct injector (DI) that provides a small amount of auxiliary fuel (<5% of the total system fuel) and a spark plug to ignite that charge.

The corresponding patent has several drawings, all of which envision a TJI injector separate from the main injector.

FIA 2016 technical regulations--

5.10.2 There may only be one direct injector per cylinder and no injectors are permitted upstream of the intake valves or downstream of the exhaust valves.

So... what might be going on...
1. TJI stuff in public domain is nonsense.
2. F1 engine makers have successfully redefined "one direct injector" away from normal ordinary meaning and are using two injectors as envision by original patent.
3. F1 engine makers have successfully developed a single injector that does a tiny injection to the pre-chamber while also doing a much larger injection to the main combustion chamber.

Individual injectors do indeed have multiple nozzles. Creative and/or technically advance application of this could support #2 or #3.

Previous public-domain rumors mention a "perforated thimble" device. This could be a pre-chamber protruding into the main combustion chamber in order to share the one allowed injector. The thimble's perforations could be oriented radially to send the pre-chamber combustion energy jets flying out radially to the far reaches of the thin, flat (high compression ratio) combustion chamber.

For this to work, the jet speed would have to be faster (or more reliable with weak fuel:air ratios) than the flame front of an ordinary combustion event. You don't want a slowly moving flame front that occurs over a large amount of engine revolution (degrees) because you have to start it well in advance, and "advance" is simply a polite way of saying you have to start combustion too early because it's too slow. Instead you want nothing, nothing, wait for it, nothing, until a tick past TDC, and then instantly full combustion ignition and pressure.

Another way (have I not used enough words already?) to describe this is to say that conventional combustion with the flame front moving outward is basically conduction-ignition, while a successful TJI system that sends flames spurting out faster than a conventional flame front would be convection-ignition.