Honda Power Unit Hardware & Software

[muzzytt]

When you build an engine you balance the rotating assembly.

So how does such bad vibrations exist?

I mean it could be the gearbox or the side mounted mgu but to not find this to this day is astonishing especially for a company like Honda

[Holm86]

When you build an engine you balance the rotating assembly.

So how does such bad vibrations exist?

I mean it could be the gearbox or the side mounted mgu but to not find this to this day is astonishing especially for a company like Honda

I also don't understand, the engine architecture is the exact same as last time Honda was in F1, just with less power and no MGU-H. How can they get it so wrong

[FNTC]

The MGU-K is 3x the size this year, and also sits next to the battery. Might be part of the issue.

[Farnborough]

There's enormous shift in regeneration passing through the crankshaft now, in comparison to previous generation of PU.

Also has to be used far more in each lap to very high degree than before.

Pistons driving a crankshaft will have a different effect to that of driving a "remote" MGU-K at front end of crankshaft by input from gearbox at the other end.
Significantly different demands to last rules.

The MGU-K will have it's own typical wave form input to crankshaft assembly when in maximum ouput too. Its more complicated than superficial views indicate, not just slapping on a bigger generation hardware to last years PU hardware.

[Farnborough]

With LS statement "like being electrocuted in a chair " with UK power supply @ 50Hz, then that would be wave form harmonic from MGU-K (given it's rotation at peak load or near to it) and possibly causing resonance/echo in the crankshaft

Very much lower you'd get "whitefinger" from something like a British twin motorcycle in 360 degree crank arrangement.

Yes this is partly in jest, but the chassis doesn't effectively MAKE vibration as such ..... switch off the PU and no vibration is present.

Interesting that MV has commented on topic about their engine, and indicated that others are giving comments (not to press) too.

You can hear it (debated at length on SF26 thread) either high level cacophony during deceleration and regeneration phase, that which people thought, erroneously, a drone.

The "screaming" under max regeneration is only the part of vibration spectrum that becomes audible, to us humans, as is moves into range of our acoustic collection devices (ears) but will be there at "subsonic" levels and available for distribution within vehicle structure.

[mzso]

Nothing on the RA626H has been optimized yet. It doesn't experience the vibrations on the test-bench, so it needs to be mated to the full drivetrain and monocoque and even then it is not sufficient.

People here are talking about past decades and applying it to today are really just bringing back a grudge. Some people carelessly uttering things like AMR should drop the engine and go with a Mercedes. They don't understand that you don't get that design freedom from a customer engine. It's the reason why they chose a works partnership. Perhaps it didn't need to be exclusive.

How do you know it didn't vibrate? Maybe they just thought that it wouldn't be a problem.
On the other hand AM didn't deliver a chassis (and gearbox?) until very late. So they are at least partially to blame. If they could have tested everything together since early January, they could have fixed everything for testing, and everything could have went smoothly.

I'm not sure how many things I can keep going around correcting but I need to stop things from propagating.

- Nothing on the RA626H has been optimized yet.
It has, It's been running on a dyno for months.
- It doesn't experience the vibrations on the test-bench, so it needs to be mated to the full drivetrain and monocoque and even then it is not sufficient.
They are now testing with the full car Dyno and have taken the battery out to finish optimize the PU. So they have been able to replicate the issue. The vibrations aren't being caused by the ICE alone. It's a combination of interconnected devices. The result is kind of like rubbing your finger around the top of a Chrystal wine glass at just the right speed that it starts to ring (resonant vibration). In this case there isn't ringing but the battery start to shake apart. I presume that the higher the ICE RPM the louder the ringing was getting.
- note For now they're exploring fixes/workarounds that do not involve changing the PU/gearbox,etc. I don't know what they are doing but I would guess they're making changes to the dampers between all the devices including the battery and the chassis.

It feels like you should have quoted ispano6 directly. However, how do you know for a fact what causes it, when Honda is still investigating?
Also. As far as I understand resonance requires external vibration frequency matching the resonant frequency of an object. So how can resonance be an issue if the vibrations in a PU constantly and very quickly change. (apart from reaching top speed, without hitting the limiter)

[vorticism]

There's enormous shift in regeneration passing through the crankshaft now, in comparison to previous generation of PU.

Also has to be used far more in each lap to very high degree than before.

Pistons driving a crankshaft will have a different effect to that of driving a "remote" MGU-K at front end of crankshaft by input from gearbox at the other end.
Significantly different demands to last rules.

The MGU-K will have it's own typical wave form input to crankshaft assembly when in maximum ouput too. Its more complicated than superficial views indicate, not just slapping on a bigger generation hardware to last years PU hardware.

Good point. It all passes through the crankshaft. You may be on the right track there, also with the geartrain harmonics you brought up. The MGUK transmission upstream of the crankshaft upstream of the (AMR's new) main gearbox.

[mzso]

Hm. Maybe Honda decided that the pistons should move in unison.

A truly remarkable press conference from Newey. My sense is that he's resistant to the idea that his chassis could be the cause of the vibrations and is putting the onus of fixing it squarely on Honda. I can't see how something in the way the engine interacts with the mounts or the transmission is not the primary cause of these issues which were clearly absent from the test bench. I wonder if the shorter battery lets them move the engine up closer to the driver and this is a contributor to the increased shaking. I'm not sure the blame for this is Honda's alone.

But where can I watch or read the whole thing?
How could be the car the source? It's the engine that vibrates. But why does it vibrate too much? Again I'm reminded of the 919 issues where they had to re-design it with a new crankshaft.

[Farnborough]

There's enormous shift in regeneration passing through the crankshaft now, in comparison to previous generation of PU.

Also has to be used far more in each lap to very high degree than before.

Pistons driving a crankshaft will have a different effect to that of driving a "remote" MGU-K at front end of crankshaft by input from gearbox at the other end.
Significantly different demands to last rules.

The MGU-K will have it's own typical wave form input to crankshaft assembly when in maximum ouput too. Its more
complicated than superficial views indicate, not just slapping on a bigger generation hardware to last years PU hardware.

Good point. It all passes through the crankshaft. You may be on the right track there, also with the geartrain harmonics you brought up. The MGUK transmission upstream of the crankshaft upstream of the (AMR's new) main gearbox.

I'd suspect the gearbox in importance less than other potential input. These are quite well known and usually with the gearset components cut by specialist outsourced producers. They can be marginal though (with some notable failures seen over the years) with the gears fairly slim in form factor considering how much bhp they handle.

Its that interaction at the front of crankshaft itgat could be more in this chief suspect zone, and without knowing the frequency and waveform out in public, that's just a strong suspicion.
Its a significant load, 350 kW? to place through there at the aggressive deployment, positive & negative, we see in this rules set. They did state they couldn't run it above the 250 kW regeneration threshold too.
That gearset would appear to sit right up against the carbon tub bulkhead too, with almost direct transmission potential to excite the tub.
Honda have long history in bike engine architecture of "flipping" crankshaft firing interval too, and some possibility of firing order arrangement as different from previous. Would have thought the other teams would have picked up on a signature pulse change though if that were present. Although not heard running much in reality.

We may see them sticking acoustic modifying pads around the carbon monocoque in attempt to quench the peak effects by damping resonance. Often found in car doors near the speakers of significant output.
Perhaps a 5 kg or so hit on weight would be worthwhile as contingency for this event.
Perhaps a trip by the AM mechanics down to local in car hi-fi emporium for supplies would pay off.