Honda Power Unit Hardware & Software

[PhillipM]

Carbon fibre doesn't deform like that, so your analogy doesn't hold up.

[GhostF1]

Carbon fibre doesn't deform like that, so your analogy doesn't hold up.

It's worth pointing out that while it's likely, we don't "know" the exact material/combination of material utilised in the track rod... And frankly it's very clearly bent in the photo, which again is unlike Carbon fibre so whether you believe it or not is sort of irrelevant and it would definitely of had an effect on the steering weight/response.. So we can't really shoot any theory down at this point.

Your theory where you simply don't believe it and think it's all hydraulics related, while it sounds good, it doesn't hold up by the fact Perez had the same related failure and yet zero symptoms displayed in steering or hydraulic systems. So we'd have to ignore a ton of variables for that to hold up at all.

Whatever it is, the only symptom displayed on both cars was a reduction in power that was increasing in severity, starting 2 laps prior to the shutdown (according to Perez). So it wasn't a sudden failure which is weird for a pump of this type. They don't tend to slowly tire out over a 5 minute period before dying entirely. It does hold some weight that there are connections that were slowly decaying away and disrupting the fuel flow to the engine caused by either this new fuel mixture or more likely, a combination of that plus high fuel temps until the connection eventually just let go and totally starved the Power Unit and caused the shutdown.

As for Perez's car turning off entirely when the engine cut out. There is a pattern of Honda powered cars tending to do that regardless of the failure type over the years. There are many examples where the wheel blacks out after a failure unrelated to the electronics almost like a safety net. They can reactivate it. Also the fact there was no concern regarding the handling the car to get it off track by the marshalls, which there usually is if something related to the electronics/battery/hybrid system has malfunctioned tends to imply it was all ok on that side.

[PhillipM]

Slow loss of pressure is very common for a high pressure direct injection pump if it's fatigue or wear issues - they don't have seals or rings so if the fuel bypasses the piston from wear/fatigue, once it starts it just gets worse and worse as it washes the lubrication off the cylinder walls and wear rapidly accelerates.
You even see that in road car diesels and they're self-lubricating to an extent.

As for the trackrod, one for the other thread yes so I'll take any later discussion there instead - but suffice to say I don't see any bend in Scarbs photo, maybe I'm looking at it wrong, but the only source we had for that was an off the cuff comment at the time of "maybe we've bent a steering rod" - that was before the car was inspected in interviews.
Not to mention if the rod was bent all it would do is knock the toe out, for it to be almost locking solid as Max was describing, you would had to have pinched/overarticulated the spherical bearing on the outboard end and knocked it out of round, which would be a very strange error for suspension design indeed, especially for a team of Red Bulls calibre.

[holeindalip]

That is interesting.

Many don’t realize that the cam driven fuel pumps and oil pumps serve secondary roles as camshaft dampers.

I wonder if it is something deeper routed in the engine causing these harmonics (firing order and the rapid combustion concept).

Thats indeed interesting. If it is the high pressure fuel pumps I think prior to the failure one should hear differences in the noise of the combustion, because the pump pressure drops etc. Can anyone confirm this? That could support this hypothesis.

Nope, you should and probably (if Honda engineers are clever enough to develop such a engine, then well...) would not notice it.

ECUs always (afaik) feature a lookup table for injector rail pressure (no matter if port or direct injection), where through some pretty simple algorithms the fuel injection duration gets increased and decreased depending on the currently existing pressure. The additional time needed during low pressure operation should be negligible, since the default injector throughput should be enough to offer a sufficient window for adaptation.

If, however, the pressure drop gets too strong and the fuel flow is suddenly not enough, the ECU should and (afaik) actually did (onboards sounds like that to me) de-rate the engine so that the pressure can be kept at a minimum acceptable level. If the pump (or it's drive, I would say the first one) is dead, the ECU will sense non-acceptable injector rail pressure and then will stop the engine operation, as doing anything else is literally the same as sitting on top of a dead horse and trying to really motivate it to stand up and move.

While some people said, that Perez electronics died during the spin - which I found very weird, since a dead engine should not result on car shutdown - I think that after everything I read and heard, it's safe to say that the engines are fine. They sounded perfectly well until they stopped. They for sure didn't go out on fuel, nobody - literally nobody - working in F1 in a position to decide on fuel load would do such a miscalculation.

Why the pumps failed.... I don't know. It can be loads of stuff. Maybe the cams on the shaft actuating the pump have to strong of a acceleration or Honda tried to go with a "more lobes, less lift" approach in order to try further stabilizing the fuel rail pressure (which I find very possible regarding their combustion concept) but it doesn't go well with the new pump since they are now not using Bosch anymore.... But it's weird. They should have seen it on the Dyno. Definetly. Maybe RB just f****d up the fuel system up to the PU, since AT didn't suffer such a failure.


And regarding Gaslys failure.... Well, that's just bad stuff from Honda. I hate to see that, they were so reliable last year. But they still have time to make up for that. Probably just too much hardcore weight reduction around the MGU-K. But things like that shouldn't happen to Honda anymore. Get it together guys.

EDIT: If the HP pump was the failure point, and not the internals failed, but the actuator "shaft" and it's spring (meaning: it got up to its failure point where it first didn't return the pump piston back quick enough and then in the worst case scenario broke), we could very well see an actually dead engine because of the debris that potentially had some revs time to cause havoc or straight up chilled the camshaft and the bearings by seizing up the pump actuator. Let's pray, that this is not what happened.

Excellent info, the big three auto manufacturers in the states used the Bosch cp4 high pressure pumps in their 1-ton diesels at one point or another and now have class action lawsuits against Bosch for causing all kinds of damage to engines. The lifters in the pump would get turned sideways because of dirt/debris in the fuel and cause excessive wear which in turn would send metal shavings to the injectors. Pump cavitation could cause the same issue (air in a pressurized system will actually cause micro explosions).

[Polite]

Low fuel pump is MAGNETI MARELLI; hi pressure fuel pump is Bosch.. and are mandatary.

[HPD]

[mzso]

Those are not very healthy downshifts. Couldn't he have gone into neutral?

[glenntws]

Those or not very healthy downshifts. Couldn't he have gone into neutral?

Direct shift into neutral isn't possible I think. Anyways, he probably tried to start it back up again and keep the engine alive somehow.

The downshifts sound like that because there's essentially no power and the ECU probably went into shutdown mode where no ICE torque output compensation for shifting up/down can happen. The engine essentially just wants to stop and the downshift accelerates it up pretty violently again and again.

[velizare]

https://f1-insider.com/formel-1-red-bul ... den-42269/

„Um es einfach darzustellen. Ein Vakuum im System der Benzinzufuhr hat dazu geführt, dass der Motor kein Benzin mehr bekam. Ich denke, wir können das Problem schon in Saudi-Arabien am Wochenende lösen.“

in english: to put it simple: there was a vacuum in the fuel supply prohibit the engine from getting fuel. i think we can solve this problem already in this weekend.

to be honest i don't buy it. it can explain the case of sergio, but max was sailing about a minute long and he also tried to restart the engine using the mgu. what kind of vacuum lasts so long?!

[PhillipM]

Vacuum causing cavitation can do a lot of damage to the high pressure pumps that feed the injectors, cavition bubble damage is severe at those kind of pressures.

[velizare]

then he could say the air bubble damaged the high pressure pump, and that was it.

[Big Tea]

Vacuum causing cavitation can do a lot of damage to the high pressure pumps that feed the injectors, cavition bubble damage is severe at those kind of pressures.

Looking at the diagram Scarbs published, there is a 'priming ' pump low in the tank, which should have supply at all times, as there has to be a sample left even after the finish, feeding a distribution pump (pushing to it? ) which then goes to the high pressure pump. As the lowest and mid pump are always 'filled' I have trouble visualising where this Vacuum is being stored?

[AR3-GP]

Vacuum causing cavitation can do a lot of damage to the high pressure pumps that feed the injectors, cavition bubble damage is severe at those kind of pressures.

Looking at the diagram Scarbs published, there is a 'priming ' pump low in the tank, which should have supply at all times, as there has to be a sample left even after the finish, feeding a distribution pump (pushing to it? ) which then goes to the high pressure pump. As the lowest and mid pump are always 'filled' I have trouble visualising where this Vacuum is being stored?

The fuel really shouldn't have vaporized on the high pressure side because the pressure keeps the fuel in the liquid state. So one would have to conclude that a sufficient amount of fuel vaporized on the low pressure side (at the primer or collector pump). The pump itself can cause the fuel to vaporize by a sort of cavitation effect I would imagine at the pump impeller. Heat soak under the safetycar and almost empty fuel tank likely enabled it. It never occurred in qualifying.

[vorticism]

What are the odds of the vacuum forming in the fuel cell? A failure of the vacuum breaker valve/breather whatever such device might be called.

[Big Tea]

Vacuum causing cavitation can do a lot of damage to the high pressure pumps that feed the injectors, cavition bubble damage is severe at those kind of pressures.

Looking at the diagram Scarbs published, there is a 'priming ' pump low in the tank, which should have supply at all times, as there has to be a sample left even after the finish, feeding a distribution pump (pushing to it? ) which then goes to the high pressure pump. As the lowest and mid pump are always 'filled' I have trouble visualising where this Vacuum is being stored?

The fuel really shouldn't have vaporized on the high pressure side because the pressure keeps the fuel in the liquid state. So one would have to conclude that a sufficient amount of fuel vaporized on the low pressure side (at the primer or collector pump). The pump itself can cause the fuel to vaporize by a sort of cavitation effect I would imagine at the pump impeller. Heat soak under the safetycar and almost empty fuel tank likely enabled it. It never occurred in qualifying.

What I mean is the primer is gravity fed this could struggle 'sucking,' but there had to be a considerable amount still in the tank as there were at least 3 laps plus the bit for test (tank vented so no vacuum). this pump then 'pushes' fuel to the main pump, so there should be no scavenging problem or air drawn with fuel. from here, I would imagine there would be a sufficient flow to the HP pump, which will be a piston not* screw? and should not produce cavitation.

I am overlooking something?

Edit not*

Edit again, internal engine pressure bypassing here could? If it is cam driven