Honda Power Unit Hardware & Software

[GoranF1]

The new engine will only work on Friday, with Alonso. If all goes well, it will stay.
Vandoorne: Engine will change but not evolved.

https://twitter.com/AlbertFabrega/statu ... 1618306048

https://twitter.com/AlbertFabrega/statu ... 5209247744

I think Albert is talking about penalties here not HP.

[kfrantzios]

For Baku, HondaHier has the right product on Amazon.de! A part of the build-up in baggage that was supposed to debut in Canada. There are different statements about the scope of the package. Honda has advised McLaren 12 hp, but this could be deliberately deeply stacked, in order not to have to explain afterwards, why less than promised. From other sources, we hear that almost half of the PS's profit was mobilized, which Honda wanted to reach with the conversion to the prechamber ignition. That would be about 30 hp.

McLaren will try the modifications on the internal combustion engine, turbocharger and MGU-H in Friday training. This costs both drivers. Both have five turbochargers and MGU-H in the pool. Friday is a test "Family Safety Drive" on the Hockenheimring - join now and win !. Honda must first check whether the characteristics correspond to the operations on the engine. If the driveability suffers, on Saturday the old engine specification is backed up.

AMUS: http://www.auto-motor-und-sport.de/form ... 86461.html

So is it going to be 30 after the pre chamber mod or is it going to be 60 after the change?

Not even the writer knows. He is reffering to two different sources.
Source 1 says that Honda will bring 12hp in Baku and he speculates that it could actually be more but Honda is very frugal in their promises.
Source 2 says that Honda has made progress with the prechamber design. The source speculates that this update's target is 60hp. They have completed half of it and will bring it in Baku. This could be about 30hp. The other half will be completed after summer vacations update

So in Baku if everything goes as planned the power increase will be from 12 to 30hp

(I can read German)

[godlameroso]

I don't expect anything until the last quarter of the season. Maybe some actual progress could sway McLaren to stay with Honda. I just hope they don't do something hasty like pull the plug before the engine becomes competitive.

[Dons!mon]

I think it means 30 in total.. 12 now and in the next update another 18.
I'm not sure

I am reading this as Honda saying 12hp to downplay expectations but they think it's more like 30hp. And that 30hp is half what they are expecting to gain but they have held back that other part of the update.

This is how i hoped it says....someone who knows german can maybe be more precize whit translation?

I can confirm that it actually means that Honda has promised 12hp at least but the journalist thinks it could be an understatement because honda maybe don't wan't to be blaimed again afterwards when it wouldn't met expectations. Other sources tell that the new honda engine gained 50% of what honda was expecting to gain when they switch to PCI. That means that this upgrade contains the whole 30 hp.
Sorry for my bad english, i am from switzerland

[gruntguru]

Reason for tumble in TC-GDI is mainly mixture preparation. The tumble motion is most prominent when the piston is close to BDC.

Nice post and pics.
I would think the main reason for tumble replacing swirl is the pent-roof chamber and the difficulty of producing swirl without reducing gas flow.

Tumble tends to extinguish rapidly as TDC is approached - unlike swirl. The "tumble racetrack" becomes a slim rectangle with two long straights. The "swirl racetrack" remains circular (with - in many designs - a reducing diameter which increases velocity. Think diesel with chamber in piston crown.)

The charge motion is not due to the piston or combustion chamber shape, it's rather the other way round.

The changing chamber shape as TDC is approached is entirely responsible for extinguishing tumble but not swirl.
.

The big difference between Diesel (swirl) and Otto (tumble) is, that a Diesel engine needs macroscopic charge motion at/around TDC, because, at least close enough, injection = ignition. So the mixture formation or preparation happens at/around TDC. For an Otto combustion system, the injection happens (mostly) during the suction stroke, thus giving loads of time till ignition. So you need macroscopic charge motion during the suction stroke and at the beginning of the compression stroke. However, for the combustion itself you want microscopic charge motion to increase the burn speed or reduce the burn duration. With that you get closer to isochoric combustion, which is generally beneficial for your thermal efficiency. So you break up the macroscopic tumble motion and end up with microscopic small-scale turbulence (i.e. eddies) with a very high turbulent kinetic energy.

Maybe as a general sidenote: Combustion in piston-engines only works in a range of engine speeds because it is a turbulent combustion. The turbulence increases with engine speed, and with that the turbulent combustion velocity increases. The laminar combustion velocity stays pretty much the same, so with laminar combustion you wouldn't be able to speed up.
With that being clear (hopefully), it is clear, why you want as much turbulence as possible for pure combustion efficiency (isochoric combustion as somewhat ideal). However, you have to balance that with the effort to create this turbulence, as mentioned by someone.

But you can actually give up quite a lot of flow efficiency of the intake ports to achieve more tumble. There are (good) TC engines out there that loose up to 30% of flow coefficient of the intake ports/valves compared to really good NA engines and end up with state-of-the-art efficiencies. You have to design the turbocharger accordingly, obviously.

The benefits of swirl vs tumble in SI engines depends on engine speed. At lower speeds (< 4000 rpm), swirl is better able to maintain turbulence near TDC. http://www.motortecmagazine.net/the-fut ... e-engines/

[n4rf]

The changing chamber shape as TDC is approached is entirely responsible for extinguishing tumble but not swirl.
.

Yes, no discussion there. What I meant was you don't design the chamber and then say "that's the charge motion I've got to live with", you think about the desired charge motion and design the combustion chamber accordingly.
(I've had students tell me that swirl is used in Diesel, because they have this convenient bowl in the piston (by chance) and one might as well make use of it.)

The benefits of swirl vs tumble in SI engines depends on engine speed. At lower speeds (< 4000 rpm), swirl is better able to maintain turbulence near TDC. http://www.motortecmagazine.net/the-fut ... e-engines/

Very interesting article, thanks for that!
I've noticed, that I have forgotten to mention, that I'm talking about direct injected engines. The article only covers PFI engines. Right now (it's early) I'm not absolutely sure, what that will affect in which way, but the mixture formation is obviously different and much more of a challenge for a DI engine compared to PFI.
One thing that is a big difference is, that scavenging is actually perfectly fine and often desirable for DI engines while it is almost a no-go for PFI engines because you will get fresh mixture rather than air in the exhaust system, leading to thermal problems and somewhat stupid raw emissions. For a DI engine, scavenging is used to reduce the residual gas content in the combustion chamber. This can be useful in the entire operating range, depending on the engine. But it is almost always beneficial at full load.
I'm quite curious about the mentioned disadvantages for CR higher than 11 for the swirl motion. At least for performance NA engines (like some of the examples shown in the article), you would generally try to get something in the 12-13 area, just to get the thermodynamic advantages of a higher CR.

Maybe we're drifting a bit away from the actual topic of this thread, but it's an interesting topic.

[GoranF1]

https://twitter.com/hlawiczka/status/878131527023861763

[CLKGTR]

Honda brings 30 BHP upgrade in Baku
Some of that gain is definitely from new Castrol fuel
https://maxf1.net/en/honda-brings-30-bh ... e-in-baku/

[etusch]

We need max speeds data as soon as it is available

[marvin78]

We need max speeds data as soon as it is available

Because that's an indicator for what? Not much.

[GoranF1]

Van 313
Alo 303

[etusch]

Van 313
Alo 303

Maybe FP2 will be better to see

[aran.vtec]

"on Last runs alone, Alonso is about 30km/h slower than Hamilton down the main straight"

From F1 live

[McL-H]

Van 313
Alo 303

Maybe FP2 will be better to see

Sure. They are running calibrations and slowly unlocking more potential. The full potential of the new engine may not even be unlocked until the next GP. I would expect it to be faster tomorrow though.

[Angel]

Van 313
Alo 303

Maybe FP2 will be better to see

Sure. They are running calibrations and slowly unlocking more potential. The full potential of the new engine may not even be unlocked until the next GP. I would expect it to be faster tomorrow though.

Of course... being a new spec they have to relearn the characteristics from it before going full steam!
FP2 will be better and tomorrow will be better also. (I think... and hope!)