Honda Power Unit Hardware & Software

[godlameroso]

It doesn't say much, just that there is a rumored 40hp. If rumors are true then Honda engine should be a match for Mercedes. As Honda was down ~15hp to Mercedes. Mercedes is expected to bring 30hp for next year, which would put the difference at 5hp, IF the rumors are true.

Realistically we won't know until the rubber meets the road. I know Honda had something ready to go on the car by August/September, that was substantially better than the power unit they raced 2020 with. Will be interesting to see what else they can improve in a 7 month span.

The power unit is 5kg heavier next year, which means all 4 will now be at or very near the weight limit.

It is incredibly hard to make the power unit 145kg.

The ICE itself is ~90kg, 25kg for the battery pack, 15kg for the electric machines, 10kg for the turbo, then charge piping, plenum, exhaust pipes sensors, pumps, etc. It's not easy that's for sure.

[_cerber1]

As Honda was down ~15hp to Mercedes.

15 hp? How then did Verstappen lose 0.9 seconds at Monza?

[godlameroso]

As Honda was down ~15hp to Mercedes.

15 hp? How then did Verstappen lose 0.9 seconds at Monza?

In the corners and straights, .5 in the corners .4 on the straights. Watch the Abu Dhabi pole comparison you see Bottas was always faster on the straights. It was worse in Austria, Verstappen had a much better exit out of the second hairpin and he still lost time down the straight

[Bill]

drag and lots of drag Remember Gasly won monza with the same Honda powerunit

[_cerber1]

drag and lots of drag Remember Gasly won monza with the same Honda powerunit

It was difficult to lose from where Gasly found himself after the red flag. Still, Carlos was able to catch up with him on older tires. So, that theory about 15 hp. clearly does not correspond to reality, especially since in this topic there have been statements more than once that Renault is significantly inferior to Honda. The gap is clearly larger.

[Sieper]

And why are we only looking at Monza? This was an outlier in performance for RBR Honda. They struggled with qualy already. At the start Max had power issues (seemed very similar to what happened in Mugello). And at the restart again. There clearly was an issue for RBR Honda that weekend.

Also, this was one of the weekends pretty short after the new 1 power mode setting for the whole weekend, and was something that both Honda and Mercedes asked to postpone (originally planned for Spa).

[PlatinumZealot]

No need to over-complicate it. The injector sprays and creates a rich mixture cloud in the vicinity of the pre-chamber. The piston is rising, increasing the pressure in the main chamber. The pressure increase causes flow into the pre-chamber. Guess what goes in.

Yes it will go in but I just don't think it will be repeatable and get that flow rate that and get the optimal jet size you want.

It would be like a damper. Forcing fluid through fix or six tiny holes about 1.5 mm in diameter. I imagine most of it would just deflect somewhere else in the free open space instead of going into those holes.

But at least we are sure that a single injector and stratified injection with pre-chamber is used.

[godlameroso]

drag and lots of drag Remember Gasly won monza with the same Honda powerunit

It was difficult to lose from where Gasly found himself after the red flag. Still, Carlos was able to catch up with him on older tires. So, that theory about 15 hp. clearly does not correspond to reality, especially since in this topic there have been statements more than once that Renault is significantly inferior to Honda. The gap is clearly larger.

https://f1bythenumbers.com/wp-content/u ... r_lap1.svg

Who said that. Frankly the Renault and Honda have been closely matched in power output for a few years now.

I remember in 2017, an on-board side by side quali lap of Alonso and Hulkenberg in Singapore. There was very little difference in power.

[etusch]

No need to over-complicate it. The injector sprays and creates a rich mixture cloud in the vicinity of the pre-chamber. The piston is rising, increasing the pressure in the main chamber. The pressure increase causes flow into the pre-chamber. Guess what goes in.

Yes it will go in but I just don't think it will be repeatable and get that flow rate that and get the optimal jet size you want.

It would be like a damper. Forcing fluid through fix or six tiny holes about 1.5 mm in diameter. I imagine most of it would just deflect somewhere else in the free open space instead of going into those holes.

But at least we are sure that a single injector and stratified injection with pre-chamber is used.

Mazda skyactiveX engine works almost same principle without prechamber. They inject richer fuel towards spark plug just before desired combustion time. I think for a solid (I don't know if this word is right for this) jet, injection into prechamber must made very close to combustion time. Otherwise you can not be sure what will be there.

[etusch]

And why are we only looking at Monza? This was an outlier in performance for RBR Honda. They struggled with qualy already. At the start Max had power issues (seemed very similar to what happened in Mugello). And at the restart again. There clearly was an issue for RBR Honda that weekend.

Also, this was one of the weekends pretty short after the new 1 power mode setting for the whole weekend, and was something that both Honda and Mercedes asked to postpone (originally planned for Spa).

AT choosed high df to be faster at turns and McLaren could only catch at straights but they never closed gap enough to overtake. they have tow of Gasly Drs and winner is Gasly. Honda has clipping issue but again Renault can not give a victory to his costumer. I think there is nothing to discuss there. But of course this forum is for that purpose.

[rogazilla]

And why are we only looking at Monza? This was an outlier in performance for RBR Honda. They struggled with qualy already. At the start Max had power issues (seemed very similar to what happened in Mugello). And at the restart again. There clearly was an issue for RBR Honda that weekend.

Also, this was one of the weekends pretty short after the new 1 power mode setting for the whole weekend, and was something that both Honda and Mercedes asked to postpone (originally planned for Spa).

I do remember Honda finally fixed the issue after by replacing the wiring harness.

[godlameroso]

Regarding how the fuel enters the pre-chamber. The air fuel mixture is roughly evenly distributed and for the purpose of discussion can essentially be though of as much. There is an equal amount of air and fuel vapor molecules distributed through the chamber volume. As the piston compresses the mixture the concentration of the air fuel mixture increases, with a ~14:1(not actual F1 C:R) CR, the combustion chamber is 1/14th of what it was. As Mr.Flap pointed out, the pressure is around 33-34 bar. If air will fill every crevice in your body at 1 bar, imagine what it can do at 30 times that pressure?

Suffice to say, there is absolutely no difficulty in the mixture entering the pre-chamber, especially with the cylinder compression increasing the air fuel density. Furthermore, the pre-chamber is an enclosed space, its volume is at a similar pressure as the rest of the CC. If an even distribution of air and fuel is in the pre-chamber as the rest of the CC, by simple physics the pre-chamber will be much more likely to ignite the mixture than anywhere else in the chamber.

Proximity to the spark plug, plus like a deflated balloon that's pinched, even though the pressure in and out of the balloon is atmospheric, if you pinch and close off a part of the balloon, you see the air inside is enough to create some tension in the balloon. Such that the pressure inside the balloon is higher than the surrounding pressure. (possibly the philosophy behind the rotating pre-chamber).

I recently had a chance to ride Honda's 2021 CBR 1000RR, the bike with said pre-chamber. I can say the bike has extremely long gears, and after 8k rpm, when the bike runs on pure pre-chamber, it's an absolute ROCKETSHIP, but rather benign below that.

*The bike I rode does not have the rotating pre-chamber.

[Bandit1216]

Posted this one before. It's a marine gas engine with lean burn principle.

Does this apply for F1 as well? I can believe Lambda in the main chamber is about 1.7. Don't think that's anything rare. But why does the detonation point disappear at some point? Of course the lambda at the sparkplug will be richer.

I know the flame speed is a lot higher at lean lambda, but it's no where near actual detonation. I try to read a lot of articles of tuners because I tune my own car, but I have a feeling 50% of the self appointed experts don't even know the diff between lean misfire and detonation. Therefore I'm a bit lost also.

But I see no reason this graph is not applicable to F1. Big gas (or dual/triple fuel) engines are no stranger to 3 bar turbo pressure either. The newest ones are 5 bar even with sequential turbo's. They only have the option of multiple injectors, which F1 does not. We even have one technique that uses 5% diesel plume to ignite the gas that's injected in inlet track.

But this graph is perfectly applicable for high (elec)turbo-compound stratified TJI. Or is it?

[63l8qrrfy6]

Not quite perfectly applicable - that graph is a function of many parameters and will vary even between different F1 PU engine makes. But yes the shapes of the detonation and misfire zones will be comparable while the numbers on the axes can be quite different (for example the peak power BMEP is around 40 bar)

But generally speaking the F1 engines will operate in the tiny sliver between detonation and misfire, ocasionally crossing over in either zone. We can only speculate on the extent of their operating window in terms of lambda but it might not be too dissimilar to your graph.

All else being equal detonation dissapears either side of lambda 1 because the temperature of combustion decreases the more the mixture deviates from stoichiometric. This is because of the additional heat capacity of excess fuel for rich mixtures or the additional heat capacity of excess air at lean mixtures. Since the heat capacity of fuel is greater that that of air the detonations zone dissapears quicker as the mixture gets richer.

Industrial gas engines normally use one of two types of pre-chambers - either fully "passive" (gas is mixed with air, often ahead of the compressor stage) and as such the mixture is homogenous or "active" (fuel-fed) pre-chamber which allows it to run richer than the rest of the cylinder which is still fed by pre-mixed air/fuel. F1 engines must use some form of hybrid since the injector cannot be physically placed within the pre-chamber yet its spray pattern can be used to enrich it.

[Bandit1216]

That makes sence. But when there is no spark, there is no combustion, right. Unless actual detonation occurs.

So that's why turbo's in the old days used to flood fuel to avoid detonation.

So when one advances ignition to avoid detonation one only makes things less bad? I mean, ignite too early, before perfect, to avoid detonation is always worse then ignite at the right time, right?

So this is the big advantage of TJI. No risk of detonation because the mix is too lean in the main chamber, but nevertheless perfect control of ignition timing and relative high flame speed.