Honda Power Unit Hardware & Software

[wuzak]

The pictures are misleading because it's not technically TJI being used, it's an adapted form of TJI to fit F1 requirements so there are no pictures.

And it's why Renault and Honda are struggling to make the same gains. Mercedes and Ferrari used some of the same people, engineers who came up with the solution split and some went to Brixworth(Merc) and some went to Mahle. Mahle a few years later then wen't to Ferrari(2015) who had already signed the Mercedes combustion expert Cedric Cornebois in the summer of 2014 and started in Jan 2015.

It's not an accident that the two systems that work the best have shared history of engineers who have detailed knowledge of both the TJI system and it's adapted form for F1.

Mahle have been working with and supplying Ferrari since at least 2012.

Ferrari managed to poach a couple of engineers from Mercedes for 2015, but the main improvements for the beginning of the year had been already made at Ferrari.

I believe one of the engineers was a combustion expert and the other on the ERS side.

[McHonda]

The pictures are misleading because it's not technically TJI being used, it's an adapted form of TJI to fit F1 requirements so there are no pictures.

And it's why Renault and Honda are struggling to make the same gains. Mercedes and Ferrari used some of the same people, engineers who came up with the solution split and some went to Brixworth(Merc) and some went to Mahle. Mahle a few years later then wen't to Ferrari(2015) who had already signed the Mercedes combustion expert Cedric Cornebois in the summer of 2014 and started in Jan 2015.

It's not an accident that the two systems that work the best have shared history of engineers who have detailed knowledge of both the TJI system and it's adapted form for F1.

Mahle have been working with and supplying Ferrari since at least 2012.

Ferrari managed to poach a couple of engineers from Mercedes for 2015, but the main improvements for the beginning of the year had been already made at Ferrari.

I believe one of the engineers was a combustion expert and the other on the ERS side.

Sorry, I meant they went to them with TJI specifically in 2015. It was early 2015 that they expanded into other areas with Ferrari with combustion specifically mentioned in the announcement.

They got over a dozen from Mercedes alone in summer 2014, all PU engineers. Most had to serve out their gardening leave of course. Cornebois was the combustion expert and he was sidelined until Jan 1st.

[nzjrs]

Wazari san, i wanna ask two question. Firstly Which one is more ambitious, HCCI, HLSI, or turbulent jet chamber?
And second, HCCI has no room in racing engine, am i right?

I find Wazaris omission of any mention of TJI / HXXX in recent comments conspicuous. His hints in the direction of firing order and rpm range have been consistent with the audio analysis on the track.

So I guess I'm saying, is our fixation on TJI / HXXX here, at this stage, a red herring? Is there any evidence from the presumably vibration related reliability problems that indicate TJI / HXXX is at fault or even being used? It seems to me likely that its a consequence of structural changes related to weight reduction, and bearing / lubrication changes related to new technology to accommodate the higher designed rpm range.

Is TJI / HXXX a priori necessary to get benefit from the increased RPM range?

My hypothesis is Honda had a 2 stage development process for the season. The first being structural, layout and firing order changes to get to the higher RPM range. Then a Silverstone introduction of TJI / HXXX.

I don't believe Honda are ignorant, so I don't think they would have tried to do all this in one step by the start of the season. A 2 step process in this way is also afaict consistent with wazaris last and previous discussions of the different PU threads of development inside Honda and consistent with his hints.

Or I'm dreaming

[hurril]

If the injector is not in the pre-chamber, then how would the mixture get richer inside of it?

[Tommy Cookers]

[quote=gruntguru post][quote=dren post][quote="Tommy Cookers"]
it's interesting to me that Wazari asks here the question that I asked 5 years ago - why not design around systematically higher rpm ?
eg I suggested that 13000-14800 rpm had some advantages over 10500-12100
mainly 'boost' pressure would be lower ie the supercharging power reduced in greater proportion
the recoverable energy is at least the same at this lower boost
ok at that time I was assuming a mildly lean AFR not very lean
clearly if the very lean TJI or similar suffers at these higher rpm then higher rpm is not on[/quote]

I actually remember the discussion; doesn't seem that long ago! Less boost demand with similar MGUH recovery would certainly be more efficient?[/quote]

It would, but it is unlikely that thermal recovery could be maintained. If you assume exhaust mass flow stays the same you would need the same EBP also which would mean a less favourable pressure differential across the engine.
There could be something in the higher CR argument. Raising rpm by 10% would reduce fuel/cycle by 10% so peak cylinder pressure would reduce significantly if AFR is maintained (lower boost).[/quote]


broadly ....
recovery is turbine power less compressor power so remains constant regardless with boost as exhaust pressure will follow (abs) boost
frictional torque would fall with lower cylinder pressure/higher rpm so largely compensating for higher piston speed & rpm
and blowdown recovery remains unchanged with rpm and is free of cost to crankshaft power

[godlameroso]

If the injector is not in the pre-chamber, then how would the mixture get richer inside of it?

Simple, the AF mixture has nowhere else to go as the piston moves in it's compression stroke. The reason the pre chamber mixture is richer is because the volume in the pre chamber is a fraction of the main chamber.

For example a big ol beer mug can be filled a quarter of the way, but it's more than enough to fill a shot glass to the brim.

As you can imagine, creating the proper conditions in the pre and main chambers is not easy, particularly when you have to orchestrate it between 6 odd firing cylinders.

And the more precise you try to be, which is needed for maximum power, the harder it is. Because one wrong move and preignition will destroy the engine in short order.

[hurril]

If the injector is not in the pre-chamber, then how would the mixture get richer inside of it?

Simple, the AF mixture has nowhere else to go as the piston moves in it's compression stroke. The reason the pre chamber mixture is richer is because the volume in the pre chamber is a fraction of the main chamber.

For example a big ol beer mug can be filled a quarter of the way, but it's more than enough to fill a shot glass to the brim.

As you can imagine, creating the proper conditions in the pre and main chambers is not easy, particularly when you have to orchestrate it between 6 odd firing cylinders.

And the more precise you try to be, which is needed for maximum power, the harder it is. Because one wrong move and preignition will destroy the engine in short order.

You are confusing/ conflating volume with richness/ concentration.

[godlameroso]

If the injector is not in the pre-chamber, then how would the mixture get richer inside of it?

Simple, the AF mixture has nowhere else to go as the piston moves in it's compression stroke. The reason the pre chamber mixture is richer is because the volume in the pre chamber is a fraction of the main chamber.

For example a big ol beer mug can be filled a quarter of the way, but it's more than enough to fill a shot glass to the brim.

As you can imagine, creating the proper conditions in the pre and main chambers is not easy, particularly when you have to orchestrate it between 6 odd firing cylinders.

And the more precise you try to be, which is needed for maximum power, the harder it is. Because one wrong move and preignition will destroy the engine in short order.

You are confusing/ conflating volume with richness/ concentration.

I'm trying to keep it simple for the sake of discussion. Think of it this way, food in a dining room only occupies a very small amount of the dining room, it's a very lean air to food ratio. When you put food in your mouth(our pre-chamber) the food to air ratio becomes rich.

[PlatinumZealot]

I can't see how the prechamber will be richer unless there is a mechanism in place to make it so.

The idea with the shroud does not work. Why? Because a shroud would not produce the jets. Nozzle Cross sectional area to big. And I have read in papers that the nozzle holes have to be precisly machined.

So with those small nozzle holes you cannot depend on aiming part of the fel spray into the prechamber if the injector is outside the prechamber.

Also another thing. On the compression stroke be careful not to everestimate the flow speed into the chaber. Remember the gas is not moving anywhere fast it only being compressed. The actaul motion of the gas at the prechamber end would be zero and the motion of the gas at the piston end would be at piston speed. There is a speed gradient and since the distance along the depth of the prechamber is so small.. There is minimal fluid motion taking place there.. So do not expect a big inrush of gas into the prechamber if any at all.

[godlameroso]

I can't see how the prechamber will be richer unless there is a mechanism in place to make it so.

The idea with the shroud does not work. Why? Because a shroud would not produce the jets. Nozzle Cross sectional area to big. And I have read in papers that the nozzle holes have to be precisly machined.

So with those small nozzle holes you cannot depend on aiming part of the fuel spray into the prechamber if the injector is outside the prechamber.

Also another thing. On the compression stroke be careful not to everestimate the flow speed into the chaber. Remember the gas is not moving anywhere fast it only being compressed. The actual motion of the gas at the prechamber end would be zero and the motion of the gas at the piston end would be at piston speed. There is a speed gradient and since the distance along the depth of the prechamber is so small.. There is minimal fluid motion taking place there.. So do not expect a big inrush of gas into the prechamber if any at all.

It does work, the problem is you think the pre-chamber is a sort of thimble with some holes capping the spark plug, it's not quite that.

Bolded part is not entirely accurate either, the higher the cylinder pressure the faster filling occurs. Not to mention air is tumbling as it enters the combustion chamber, then piston motion creates turbulence that distributes the A/F mixture in the cc. Also the pre-chamber is quite small, doesn't need to be filled the same as the main cc, just enough to start the chain reaction. Remember air is very conceited and quite full of itself under our atmosphere, this is even moreso due to the back pressure from the turbine and over atmospheric pressure entering the cc via the compressor.

[FW17]

In a diesel prechamber is there a problem of fuel spray coming out of the prechamber?

What if the fuel completely evaporates in the chamber and forced down into the main chamber in gaseous for to prevent fuel droplets fouling the nozzle?

[Sasha]

A friendly reminder for the lost.

Honda's now CC doesn't work as planned.(Simon's design)

So it will need to be replaced with a new design.(heads and pistons)

It might not be ready until 2018 season because Honda must do the D in the R&D that they didn't do the first time.
Hope is it is ready after the Summer break this season.

[63l8qrrfy6]

Pre chambers in natural gas engines work even though in many cases the gas is mixed with air before the turbo.
No injection in cylinder whatsoever.

[Tommy Cookers]

are you sure that's right ?
eg there's engines that run gas-fuelled pre-chambers igniting conventional PFI gasoline/air charge

[63l8qrrfy6]

are you sure that's right ?
eg there's engines that run gas-fuelled pre-chambers igniting conventional PFI gasoline/air charge

yea - I think they are called passive pre chambers.
www.altronicinc.com/pdf/ignitionaccesso ... 206-12.pdf

Edit:

http://www.wtz.de/sites-en/05_DGEC/7-DG ... 07-V9.html
Pretty much agrees with what godlameroso said earlier.