Honda Power Unit Hardware & Software

[Alexf1]

It is not a torque issue. It is a suspension and gearing matter.

Thank you for clearing that up for me! In that case the PU is a performance monster next to being the most durable you can find on the grid! Was it already like that last year but hidden due to the draggy high rake concept and the Silverstone writeoff? Any hp increase to be expected as of PU2? ERS update you mentioned earlier will probably be done in sync with PU3 intro near Sep 1st homologation deadline I presume?

[Wazari]

IMO gear ratios play a huge role during the season. I personally have spent a lot of time in simulators trying to decide optimum ratios with regards to acceleration, drivability, top speed, etc. It's an agonizing process. Last year I thought the ratios were too short. Torque in all the PU's are very close so suspension, aero and gear ratios all play a big part in acceleration out of a corner.

[chrisc90]

In regard to the gearing, I wonder how much detail the teams go into to work out what ratios are best to go for. it must be a very labour intensive process but I imagine simulations will get them to 90-95% of the way there with what gearing is best suited over a full season.

[gruntguru]

Wazari San.
Torque?

[Wazari]

ICE's torque curves

[aleks_ader]

Wazari San.
Torque?

What is your gripe with it. Maybe i overfleew the discussion here. But what exactly is wrong here. MGUK can fill ICE hole and flatten its curve. MGUH link via battery or trough controller can further expand tool set for engineers to even more flatten its effect and mask low end deficiency's. Ergo ratios becomes in some sense optimization differentiator.

[glenntws]

Agree with Wazari, that gearing is a incredibly complex topic where you always make compromises. Last year gear ratios on 5 and 6 were a bit to short, I felt that the ratio between 6-7-8 could be made a bit shorter to remain in the optimal efficiency are of the engine. I would assume that while overall efficiency is very high, the area where the efficiency really peaks is actually not a very broad rpm band. Can you confirm that Wazari?

While for full high speed driving the gearing this year looks better, I do think that (for RB) this year, one can see two points where it's probably not optimal:

Low speed corners like found in Monaco. We are obviously operating on a grip limit, but having the engine in very low rpms basically forces the ECU to get more power out of the MGU-K and the MGU-H having to assist in order to keep the big turbo alive. (Btw, is efficient combustion possible in low load/pressure conditions? If would assume TJI works well, but the HCCI combustion happening at the outer cylinder walls will be instable or not possible at all - hurting efficiency) Also, much of regulation has to be done is order to keep torque steady since obviously we are talking about a transient system where boost building up can lead to sudden torque spikes (although the K probably acts as a "high frequency filter" while H and wastegate keep the turbo relatively stable.
The engine feels out of it's optimal rev range in low speed corners. A bit shorter ratios would make efficiency improve since more work can be done by the ICE directly.

Also, mid-speed corners seem to be a problem. I have a feeling, that the influence of the heavy chassis weight was maybe a bit underestimated, since the engines here really seem to struggle quite a bit some times. IMO it drains the battery too much.

But then again, everything is a compromise, and we don't know nearly enough to really say anything valuable here. My opinion would be that bigger ratios between gears 1-6 would help, but the gearing is probably just adapted to the concept of the car and to be honest. High speed cornering and straight line acceleration of the RB this year is very good. It has it's reason and one probably is the gear ratios selected.

[hollus]

Fascinating to hear about the gear ratios. I was one of the ones saying that there is enough overlap to matter little overall after making all those gear ratio threads. But maybe specific RPM situations coming out of specific corners could be tricky?
Or maybe power curves have gotten less flat?
Anyways, that weird quirk remains: any team that were losing significant lap time to wrong gearing is allowed, for 2022 only, to change the gear ratios once. So if this is not happening… maybe we are talking about hundredths of a second of lap time?
Back in 2014, when Toro Rosso finally blinked first and used the gearing joker, they changed 1st gear exclusively.

I’d be more than happy to be shown more detail here.

[NL_Fer]

Agree with Wazari, that gearing is a incredibly complex topic where you always make compromises. Last year gear ratios on 5 and 6 were a bit to short, I felt that the ratio between 6-7-8 could be made a bit shorter to remain in the optimal efficiency are of the engine. I would assume that while overall efficiency is very high, the area where the efficiency really peaks is actually not a very broad rpm band. Can you confirm that Wazari?

While for full high speed driving the gearing this year looks better, I do think that (for RB) this year, one can see two points where it's probably not optimal:

Low speed corners like found in Monaco. We are obviously operating on a grip limit, but having the engine in very low rpms basically forces the ECU to get more power out of the MGU-K and the MGU-H having to assist in order to keep the big turbo alive. (Btw, is efficient combustion possible in low load/pressure conditions? If would assume TJI works well, but the HCCI combustion happening at the outer cylinder walls will be instable or not possible at all - hurting efficiency) Also, much of regulation has to be done is order to keep torque steady since obviously we are talking about a transient system where boost building up can lead to sudden torque spikes (although the K probably acts as a "high frequency filter" while H and wastegate keep the turbo relatively stable.
The engine feels out of it's optimal rev range in low speed corners. A bit shorter ratios would make efficiency improve since more work can be done by the ICE directly.

I though the Honda deactivated a few cilinders under low load, to keep the flow/pressure up in the firing cilinders.

[glenntws]

Agree with Wazari, that gearing is a incredibly complex topic where you always make compromises. Last year gear ratios on 5 and 6 were a bit to short, I felt that the ratio between 6-7-8 could be made a bit shorter to remain in the optimal efficiency are of the engine. I would assume that while overall efficiency is very high, the area where the efficiency really peaks is actually not a very broad rpm band. Can you confirm that Wazari?

While for full high speed driving the gearing this year looks better, I do think that (for RB) this year, one can see two points where it's probably not optimal:

Low speed corners like found in Monaco. We are obviously operating on a grip limit, but having the engine in very low rpms basically forces the ECU to get more power out of the MGU-K and the MGU-H having to assist in order to keep the big turbo alive. (Btw, is efficient combustion possible in low load/pressure conditions? If would assume TJI works well, but the HCCI combustion happening at the outer cylinder walls will be instable or not possible at all - hurting efficiency) Also, much of regulation has to be done is order to keep torque steady since obviously we are talking about a transient system where boost building up can lead to sudden torque spikes (although the K probably acts as a "high frequency filter" while H and wastegate keep the turbo relatively stable.
The engine feels out of it's optimal rev range in low speed corners. A bit shorter ratios would make efficiency improve since more work can be done by the ICE directly.

I though the Honda deactivated a few cilinders under low load, to keep the flow/pressure up in the firing cilinders.

This is probably still done and helps a lot, but the are probably many cases, where cylinder pressure still gets quite down and far away from full load (best example: just above cylinder cutoff threshold. You would switch to full-cylinder running from at least 45% request of max power, so 0.45 of max pressure is quite far off)

[Wazari]

Agree with Wazari, that gearing is a incredibly complex topic where you always make compromises. Last year gear ratios on 5 and 6 were a bit to short, I felt that the ratio between 6-7-8 could be made a bit shorter to remain in the optimal efficiency are of the engine. I would assume that while overall efficiency is very high, the area where the efficiency really peaks is actually not a very broad rpm band. Can you confirm that Wazari?

......

I think overall last year all gears ratios were a little short especially 5-8 by about 75 to 125 RPM. It may not seem too significant but can make up to a two tenths difference. The "efficiency peaks" are a very small band and again deciding the ratio for every gear 1 - 8 for the entire season is a very difficult process. I am glad to see that taller gears are being used this season.

[saviour stivala]

Gear ratios selection. The 1.6l turbo hybrid gear ratio selection is a different kettle of fish from what it used to be with the NA 3.0L/NA 2.4L engines. Because torque curves/RPM operating bands are totally different. In those gone-by days with seven speed gearboxes nobody used to change individual ratios of the seven speeds decided upon/selected. What they used to do is manufacture and use three sets of different ratios for of the spiral bevels sets between the gearbox and differential. These sets of two spiral bevels ratios upped or lowered the whole set of ratios (engine to real wheels ratio) for different tracks. Torque can be multiplied by gearing-down engine speed (RPM). A F1 car producing ‘X’ torque will produce double that torque at rear wheels if driven down by 2:1 gear ratio. The higher RPM the engine spins, the more it has to be geared-down to match the rear wheel speeds. So the more its torque is multiplied. The more torque is present at the rear wheels, the greater the acceleration is for a given mass. (looking at torque values alone is very misleading). Rear wheel torque rules, but horsepower gets you there acceleration wise.

[Tommy Cookers]

... spiral bevels sets between the gearbox and differential. These sets of two spiral bevels ratios upped or lowered the whole set of ratios (engine to real wheels ratio) for different tracks.
.... The more torque is present at the rear wheels, the greater the acceleration is for a given mass
.... Rear wheel torque rules, but horsepower gets you there acceleration wise.

'set of spiral bevels between gearbox and differential' .... is ....
usually called the final drive or the crown wheel and pinion CWP ... very expensive to make ... and ....
stepdown gears can be changed instead

power and torque are inseparable - nowhere does one actually replace the other (except in Coulthard world)

[saviour stivala]

Yes. Spiral bevel set of two in-between gearbox and differential. The driver on the end of gearbox output shaft just outside the back face of gearbox casa, the driven at 90 degrees to the driver on the pinion gear shaft in the differential case, differential case is bolted to gearbox case. F1 differentials gear sets (crown-wheel and pinion) are simple spur gears (straight cut teeth).

[NL_Fer]

Do teams have calculators which can simulate the results of a chosen gear set, for all tracks of the season? Like one would enter a set of 8 gears and the system wil produce a list of laptimes and efficiency for every track?