Honda Power Unit Hardware & Software

[godlameroso]

"Citation needed".

Give the guy a break. I can vouch for him and his experience .

I know, and I appreciate his posts immensely, but honda simply forgetting/not noticing something of such importance just seemed out of whack. I find your explanation much more plausible.

I would say misjudged, even the best engineers are only human, they make mistakes. I don't think for one single picosecond that Honda didn't figure it out, of course they did. It was simply too late to change anything. If anything I admire their willingness to try something different. I don't think I personally could have designed anything better. They have way more money, resources, and brains than just me by myself.

[hurril]

When we were working on it at the early stages we didnt realise straight away that you could bypass the ES completely between the H and K and there was much debate about whether a direct link powering all the time would be legal or not as it seemd to be cut off by the Mj limit specifications.

"Citation needed".

My Memory, Of my Job - 2011

What was your job in 2011, Facts Only?

[godlameroso]

[....] The MGU-H can be clutched, and I imagine all teams clutch it, otherwise the turbine would never work at all. [...]

Sorry what??

The MGU-H is an electrical machine, and it can be controlled to be a motor or a generator, with a variable frequency drive https://en.wikipedia.org/wiki/Variable-frequency_drive . That drive together with an appropriate control electronics and algorithms can regulate out any issues regarding inertia, max boost etc. as the energy store is powerful enough to deliver wat is needed to spool up, keep spooled or brake the turbine / MGU-H / compressor assembly.
And I would go so far to say that they do not clutch it at all.

But if you use up all your ers, and have nothing to help compensate for lag, then the mgu-h becomes useless and actually hinders the turbo. Again the proof is there for you to see with your eyes. Look at Ferrari or Mercedes powered cars, they don't hit a brick wall at 300kph, they keep going, up to 330kph nor do they sound like their compressors are stalling. Even Renault.

No one uses the mgu-h in motor mode while going full throttle down the straight, but if your generator mode is causing compressor stall then you're not going to generate much electricity because, you don't have enough boost pressure, and by consequence not enough exhaust gas to drive the turbine or mguh.

[mikeerfol]

What's to argue? Unless you actually think you understand turbos better than the Honda engineers.

What specific time on the video do you think sounds like compressor stalling?

Main straight, back straight, take your pick, any time the car gets to 8th gear.

The thing is, it doesn't even make it to 8th gear!

[hurril]

Another question: I don't recall having seen pictures of the newer style of tuned exhaust runners on the Honda engine. Do you guys know of any?

Also, as I understand it from reading Facts Only's posts: I think the power needed to drive the MGU-h can be regulated by its control electronics. Though certainly it will always add more friction and inertial resistance than would be there if it [the MGU-h] wasn't.

It seems to me that the whole compounding system can be either on or off; when it's on - the engine produces a completely different sound even in idle. I've heard this listening to both the Mercedes engine and the Ferrari one. You hear the turbo spooling up and, in the Mercedes' case, it also starts cylinder-on-demand:ing.

I asked a while back (1-2 years ago now at least) what people thought were behind the different sound of the Mercedes engine. The log-style exhaust was given as the most likely culprit and I buy that. But what about the Honda engine? It most definitely has a very different, almost metallic, tone. It seems to be running a lot more rough, sounds like it misses ignitions revving up against resistance and things like this. Some people credit this to it not running properly - me: I don't think so; I think it runs very well. But why?

[Joseki]

Another question: I don't recall having seen pictures of the newer style of tuned exhaust runners on the Honda engine. Do you guys know of any?

[Facts Only]

My Memory, Of my Job - 2011

What was your job in 2011, Facts Only?

Chief Tea Boy, Tyre Scraper and Urinal Cake Replacement Executive.

[turbof1]

My Memory, Of my Job - 2011

What was your job in 2011, Facts Only?

Chief Tea Boy, Tyre Scraper and Urinal Cake Replacement Executive.

That's either a joke or some cropped up emotional trauma coming out .

I asked a while back (1-2 years ago now at least) what people thought were behind the different sound of the Mercedes engine. The log-style exhaust was given as the most likely culprit and I buy that. But what about the Honda engine? It most definitely has a very different, almost metallic, tone. It seems to be running a lot more rough, sounds like it misses ignitions revving up against resistance and things like this. Some people credit this to it not running properly - me: I don't think so; I think it runs very well. But why?

I remember that in Austin, the Honda engine had a completely different sound. It was much cleaner from that point on, if I remember correctly.

[hurril]

Another question: I don't recall having seen pictures of the newer style of tuned exhaust runners on the Honda engine. Do you guys know of any?

http://2.bp.blogspot.com/-iq6YoHTiFmE/V ... -44-52.jpg

Ahh - I _have_ seen that. Just forgot. Thank you =)

My Memory, Of my Job - 2011

What was your job in 2011, Facts Only?

Chief Tea Boy, Tyre Scraper and Urinal Cake Replacement Executive.

Ha! What about VP of Fruit?

[Wazari]

Wow, a lot of theories and good discussion. From my understanding, in very simplistic terms, not enough output from MGU-H unit in generating mode. Resonance and excessive heat from the whole turbocharger/MGU-H assembly necessitating "dial back" from target output. So cooling problem being resolved was more of a patch than a total solution. This has been resolved on paper but not totally implemented during last season due to token restrictions. Also torque output from turbine less than anticipated due to higher rotational mechanical loss than originally designed.

[Abarth]

[[...] but if your generator mode is causing compressor stall then you're not going to generate much electricity because, you don't have enough boost pressure, and by consequence not enough exhaust gas to drive the turbine or mguh.

I can't follow you. Why should the generator mode cause compressor stall?

There is, on a straight, a near stationary operation. Pt-Pc = P MGU-H (mechanical losses generously not included). The turbine produces more power than the compressor needs, and the surplus is taken over in MGU-H. And if MGU-H cannot take it over and route it to MGU-H or ES, (eg. because overheating, to small, limits of the power electronics, ...), the waste gates have to kick in to limit turbine rpm and boost pressure.

Gruntguru generously once posted somewhere the power balance of such a turbo / generator unit, depending on pressure ratio.

[Chicane]

If a non technical guy like me knew when these engines were introduced that the MGU-H powering the MGU-K directly bypassing the energy store is allowed then i am baffled how it is being assumed that Honda were not aware of this. Moreover Mclaren were earlier supplied by Mercedes and they knew what sort of deployment Mercedes engine was having. Also Honda are no amateurs in terms of resources, knowledge base, technology and history. They must have researched, assessed and put in a thorough thought process in to how they were going to go about it.

As has been pointed by some on here that they knew what they needed to do but they simply did not have the time to do it. This is exactly why they worked almost exclusively on the internal combustion engine with their tokens cos the whole turbine, compressor and the ERS needed a thorough workout to get on top of their ERS woes. These engines are so complex where one component has a cascading effect on the other so Honda knew that this was going to be a long drawn process and hence in my opinion they chose to work on these things in a parallel fashion in Sakura aimed at introduction for 2016 season.

One thing is clear cut though. As Honda themselves said they knew what they were getting in to but the enormity of it caught them out. They knew other teams were getting a lot out of exhaust harvesting but the extent of it shocked them. Point is you learn quicker in the heat of the competition. Many people say Honda should have waited it out for one more year but i don't think they would have learnt a tenth of what they have learnt in this season if they had chosen to wait for another year.

Honda had the blue print very early on on in the season in terms of the concepts they were going to pursue to make sure the exhaust harvesting does not lead to a counterproductive effect on the ICE output but the timelines are so long in terms of executing a concept, testing it and introducing it that they were helpless to do anything about it through the season due to token restrictions.

I am not going go in to the technical aspect of things cos they are not my work area but the biggest thing Honda got wrong was the design of the turbocharger cos it is one component which acts as a bridge between the ICE and the energy recovery system. Designing a turbo for an engine which is supposed to work with an energy recovery system needs that delicate compromise and Honda definitely erred there in my opinion but they could not have found out without first hand testing in the thick of the competition. I am not qualified to talk about what they got wrong in the compressor, turbine in terms of sizing, design or layout so i will leave it to the technical gurus to shed some light.

[godlameroso]

Generator mode could cause compressor stall if your compressor is dependent on high rpm to deliver boost. This is because generator mode puts a drag and slows down both compressor and turbine.

Slow down a speed sensitive turbine which uses high rpms to create boost and you can stall it. More so if you no longer have ERS power to compensate for the inertia of the mgu-h. So while going full throttle down the straight you have no battery power to compensate for the drag the mgu-h places on the turbo while it's trying to harvest, add in a rpm sensitive compressor that needs high rpm and you slow it down with the mgu-h and you get a partially stalling compressor.

[dren]

Wow, a lot of theories and good discussion. From my understanding, in very simplistic terms, not enough output from MGU-H unit in generating mode. Resonance and excessive heat from the whole turbocharger/MGU-H assembly necessitating "dial back" from target output. So cooling problem being resolved was more of a patch than a total solution. This has been resolved on paper but not totally implemented during last season due to token restrictions. Also torque output from turbine less than anticipated due to higher rotational mechanical loss than originally designed.

Sounds reasonable. Both issues compound the MGUH output. Arai has pretty much echoed this in interviews, too.

I'm also skeptical that the size zero design wasn't a compromise between packaging and target output. Honda might have had a target output of 120 or 100hp with their MGUH and then ran into issues that further degraded the output.

The KERS package they had in the works back in the V8 days wasn't targeted at the max allowable output. I'll have to go dig up the Honda paper.

[dren]

Generator mode could cause compressor stall if your compressor is dependent on high rpm to deliver boost. This is because generator mode puts a drag and slows down both compressor and turbine.

Slow down a speed sensitive turbine which uses high rpms to create boost and you can stall it. More so if you no longer have ERS power to compensate for the inertia of the mgu-h. So while going full throttle down the straight you have no battery power to compensate for the drag the mgu-h places on the turbo while it's trying to harvest, add in a rpm sensitive compressor that needs high rpm and you slow it down with the mgu-h and you get a partially stalling compressor.

This MGUH of yours must get extremely hot...