Honda Power Unit Hardware & Software

[saviour stivala]

Both a spark and an ark are capable of igniting a fuel air mix, compressed or not.

[Tommy Cookers]

Both a spark and an ark are capable of igniting a fuel air mix, compressed or not.

not so
the spark typically has by design .......
enough energy (50-100 mJ) to ignite the mix when it has been heated by compression (engine cold) and ....
not enough energy to ignite the mix when unheated ie without compression (or residual engine/exhaust heat)

yes more energetic sparks are possible by design - but this in various ways has more costs
eg an 85 kV dragster distributor has a diameter of 14" (and spark energy measured in J not mJ)

of course if there's enough compression heating no spark is needed for ignition

[vorticism]

Both a spark and an ark are capable of igniting a fuel air mix, compressed or not.

not so
the spark typically has by design .......
enough energy (50-100 mJ) to ignite the mix when it has been heated by compression (engine cold) and ....
not enough energy to ignite the mix when unheated ie without compression (or residual engine/exhaust heat)

yes more energetic sparks are possible by design - but this in various ways has more costs
eg an 85 kV dragster distributor has a diameter of 14" (and spark energy measured in J not mJ)

of course if there's enough compression heating no spark is needed for ignition

This is due to air fuel ratio being high enough to prevent ignition at atmospheric pressure? Hadn't really considered it before. I can easily ignite a mist of gasoline in any setting; however in-cylinder it must be vaporized to the extent that ignition can no longer occur.

[gruntguru]

Spill a teaspoon of petrol on the floor and fire a spark plug just above. No problem igniting air/fuel at atmospheric conditions.

[vorticism]

Spill a teaspoon of petrol on the floor and fire a spark plug just above. No problem igniting air/fuel at atmospheric conditions.

Although, hold the spark too far away from the vapor plume and it will not ignite. Perhaps that was what Tommy was getting at. The lower LEL/LFL of petrol I see listed as 1.4% (at 20*C, 1 bar); by comparison what are lean a:f ratios expressed as a percentage in SI engines?

[gruntguru]

Spill a teaspoon of petrol on the floor and fire a spark plug just above. No problem igniting air/fuel at atmospheric conditions.

Although, hold the spark too far away from the vapor plume and it will not ignite. . .

That will apply at higher pressures too I am sure.

[AR3-GP]

As we are talking about kinetic energy, the whole system needs to be able to handle this higher forces. Crankshaft, gearbox and so on. So it's clearly not just software. Their H might also be better than the competitors, but this has no direct influence on the drivability under braking.

You started out by emphasizing how aggressive MGU-K retardation mapping is the key to RB's advantage. This problem is more trivial to solve than the MGU-H. MGU-K retardation is primarily software, which is why RB can ask max to go to different maps.

Then you suggest even this is not so trivial because of the forces to consider. The ICE alone outputs 700 hp to the crankshaft. The maximum MGU-K recovery is 120Kw or roughly 160hp. The forces generated by the recovery are smaller than that generated by the ICE at full throttle. Of course you have to consider that the torque in the gear train goes the opposite direction but I don't think this requires anything special that other teams are not aware of. The harvesting forces themselves are just software. Clearly RB is not executing it as well as other teams.

I agree on your point that clearly MGU-K harvesting would cause the driveability compromise but that's a different point to make, as opposed to implying the MGU-K harvesting is where the Honda PU advantage lies. From my understand, the MGU-H is where the Honda superiority comes from. That in addition to having an efficient, low loss, MGU-K.

[AR3-GP]

Great article on '22 PU: https://www.racecar-engineering.com/art ... -rbpth001/

‘The RBPTH001’s reliability target is to cover eight grands prix with a single power unit, as it has been for the last few years. That is a base position. It’s a fine balance to strike but, ultimately, we want to achieve the three power unit regulation without incurring penalties. ‘The 2022 power unit achieved a higher thermal efficiency than in 2021, even with the lower calorific value of the E10 fuel. I can confidently say it’s well above 50 per cent, but that is all I can say. This is thanks to the many detailed changes and developments around the new combustion regime.’

[vorticism]

Spill a teaspoon of petrol on the floor and fire a spark plug just above. No problem igniting air/fuel at atmospheric conditions.

Although, hold the spark too far away from the vapor plume and it will not ignite. . .

That will apply at higher pressures too I am sure.

Yes, short of initiating CI however that distance will increase relative to the LEL/LFL at several hundred bar.

Great article on '22 PU: https://www.racecar-engineering.com/art ... -rbpth001/

The latest engine oil can withstand significantly higher temperatures than its predecessor, and that affects the design of many other parts of the car...

Probably a reference to the cooling oil for these printed pistons.

[AR3-GP]

Although, hold the spark too far away from the vapor plume and it will not ignite. . .

That will apply at higher pressures too I am sure.

Yes, short of initiating CI however that distance will increase relative to the LEL/LFL at several hundred bar.

Great article on '22 PU: https://www.racecar-engineering.com/art ... -rbpth001/

The latest engine oil can withstand significantly higher temperatures than its predecessor, and that affects the design of many other parts of the car...

Probably a reference to the cooling oil for these printed pistons.

I also think they somewhat hint at other aspects such as the low drag of the RB. I don't know the differences to the other engine manufacturers, but smaller coolers means less drag.

[vorticism]

I also think they somewhat hint at other aspects such as the low drag of the RB. I don't know the differences to the other engine manufacturers, but smaller coolers means less drag.

Certainly the sidepod and roll hoop inlet sizes shrank this year, evident in photos.

[Farnborough]

As we are talking about kinetic energy, the whole system needs to be able to handle this higher forces. Crankshaft, gearbox and so on. So it's clearly not just software. Their H might also be better than the competitors, but this has no direct influence on the drivability under braking.

You started out by emphasizing how aggressive MGU-K retardation mapping is the key to RB's advantage. This problem is more trivial to solve than the MGU-H. MGU-K retardation is primarily software, which is why RB can ask max to go to different maps.

Then you suggest even this is not so trivial because of the forces to consider. The ICE alone outputs 700 hp to the crankshaft. The maximum MGU-K recovery is 120Kw or roughly 160hp. The forces generated by the recovery are smaller than that generated by the ICE at full throttle. Of course you have to consider that the torque in the gear train goes the opposite direction but I don't think this requires anything special that other teams are not aware of. The harvesting forces themselves are just software. Clearly RB is not executing it as well as other teams.

I agree on your point that clearly MGU-K harvesting would cause the driveability compromise but that's a different point to make, as opposed to implying the MGU-K harvesting is where the Honda PU advantage lies. From my understand, the MGU-H is where the Honda superiority comes from. That in addition to having an efficient, low loss, MGU-K.

The comments made recently by MV about rear locking, then slow down change etc seem to indicate more usage of recovery and engine brake effects than generally discussed. There's substantial advantages I believe, but that's dependent on driver adaption/style to accommodate this.
Braking through the diff is fundamentally very different to rear brake via disc. The disc has parity across the axle, making it more difficult for front grip in turning the car, rear bias may help but still equal across the two tyres.
Through the diff though (no secret but likely considered older technique) as the input to diff shaft is braked through engine torque or recovery, then with the diff locking percentage backed out at corner entry phase, will cause the inside wheel to travel backwards, that's in relation to the outside wheel THIS IS IMPORTANT. The affect of this is to brake the inside rear wheel to steer the vehicle into the corner from braking bias.
Note, this isn't a secret mode or hidden facility, but something most every rally driver will do, and probably more noted as pure technique in day's of H pattern gearbox particularly at places like Monaco where downshift could easily skip ratio to drag the car toward tight apex.
How that could be applied currently, with driver behaviour, is to ramp up the recovery through initial phase of heavy braking, then supplement this with very late and very fast down changes to keep that retardation high through the differential. Running friction brake bias trim to accommodate date this would be particularly useful.
If driven like this, the car has significant potential advantages in entry to high braking corners. Those situations when MV gets down inside another car but still turns it, would be one area to maximise this. Often now labelled as "dive bombing" the RB holds significant advantage there it seems, to the surprise of others.

Evidence suggests that with DR it was an attribute tgat was there even then. Current drivers ability to hone this is important. Notice when CL was chasing SP at Imola last year, entry into first chicane when it looked like CL was lining up a pass, then entering the brsking phase and tge Ferrari seemed to go backwards.
Also the pass on LH at Circuit of the Americas at the end of back straight last year.

[Farnborough]

Could show in drive shaft vulnerability too, very high torque reversal cycles may bring durability closer to their realistic capabilities.

[Tommy Cookers]

.... Braking through the diff is fundamentally very different to rear brake via disc. The disc has parity across the axle, making it more difficult for front grip in turning the car, rear bias may help but still equal across the two tyres.
Through the diff though (no secret but likely considered older technique) as the input to diff shaft is braked through engine torque or recovery, then with the diff locking percentage backed out at corner entry phase, will cause the inside wheel to travel backwards, that's in relation to the outside wheel THIS IS IMPORTANT. The affect of this is to brake the inside rear wheel to steer the vehicle into the corner from braking bias.....

the above 100% wrong IMO

the part that's not wrong .....
delayed downshifting requires a different division of rear braking between mechanical and regenerative
because the relationship between rotational KE and translational KE changes with the gear
so yes changing brake bias on the fly could help

the 8 gears allow roughly a 2:1 range of velocity (rpm) relationship choices - (this is a 4:1 in energy terms)
this is very helpful to the electrical engineering side - but not helpful to the driver etc

[Farnborough]

And the reason you feel it's wrong is ?