Honda Power Unit Hardware & Software

[ncassi22]

So do I understand this correctly? For next years engine they'll be using the fuel heater and trick-injectors
to inject fluid at a super critical state (more homogeneous), and then use TJI for combustion (later/faster/more complete)?

[Tommy Cookers]

TJI etc are basically about combusting as fast and fully as ever before a leaner mixture than ever before

heat dilution is the name of the concept
ie higher boost and so greater air massflow - this means less heat energy going to coolant and less heat energy being wasted in exhaust

so more work being done on the pistons
and more work being done on the turbine - though this is mostly taken up by the extra work needed to generate the higher boost

knowing the actual boost used would tell us how much leaning is being used

[godlameroso]

Look a few pages back, apparently we were pretty accurate. Honda uses right around 4 bar boost pressure apparently(or is it absolute). Some estimates put Mercedes running 4.5 bar.

*edit It's absolute.

[gruntguru]

So do I understand this correctly? For next years engine they'll be using the fuel heater and trick-injectors
to inject fluid at a super critical state (more homogeneous), and then use TJI for combustion (later/faster/more complete)?

Honda were one of the originators of heated fuel in F1 with the RA168e. I would be surprised if they are behind other teams on this.

Temperature back then was 80*C IIRC - that is a long way from super critical. I would be worried about spontaneous ignition if you injected super critical fuel.

[BrunoH]

http://www.f1technical.net/forum/viewto ... ?f=4&t=445

back in the day they were doing the opposite in F1.. they were cooling the fuel for extra performance... hence the ban...

[nokivasara]

I tried to find an answer to this but didn't so maybe you guys can help me out:
Why does the Honda rev higher than the others, I thought the sweet spot was around 10500-11000 RPM or thereabouts, but on the on-board footage of the McLaren they rev much higher. More than 12k Rpm.
Why is that?

[BrunoH]

my guess is to make the make the turbo spin harder ( more rpm ) , making more harvesting via the mgu-heat? could be one of the solutions they found to get more electric energy,
the other it might be to compensate the smaller turbine!? so for them to make the same intake turbo pressure as the other who are running a bigger turbine they need more compressor rpm also and the way to do it could be more exhaust gases

or maybe a combination of both... but maybe someone could help on this one... as im not exactly sure either. but those are my assumptions.

[Pierce89]

I tried to find an answer to this but didn't so maybe you guys can help me out:
Why does the Honda rev higher than the others, I thought the sweet spot was around 10500-11000 RPM or thereabouts, but on the on-board footage of the McLaren they rev much higher. More than 12k Rpm.
Why is that?

It just seems that is what the Honda guys have to do it to be competitive. They apparently can't make max of power at the same rpm, maybe because their compromised compressor can't quite match max boost pressures.

[Pany]

I tried to find an answer to this but didn't so maybe you guys can help me out:
Why does the Honda rev higher than the others, I thought the sweet spot was around 10500-11000 RPM or thereabouts, but on the on-board footage of the McLaren they rev much higher. More than 12k Rpm.
Why is that?

It just seems that is what the Honda guys have to do it to be competitive. They apparently can't make max of power at the same rpm, maybe because their compromised compressor can't quite match max boost pressures.

That is not the reason. They can not yet reach the elevated compression rate of mercedes. This means they have not the same quantity of air injected per cycle. In order to condact the right amount of air flow to the turbo generator the only solution is to compensate by incrementinc the rpm. Very simple. The problem is that at higher rpm the efficiency drops a little because of more energy wasted by friction and engine heat exchange. Next year they will inprove tji combustion or other tricks with the aim to increase compression ratio. This way not only peak pressure is higher but more important you increment air flow to exhausts hence tuebo

[nokivasara]

I tried to find an answer to this but didn't so maybe you guys can help me out:
Why does the Honda rev higher than the others, I thought the sweet spot was around 10500-11000 RPM or thereabouts, but on the on-board footage of the McLaren they rev much higher. More than 12k Rpm.
Why is that?

It just seems that is what the Honda guys have to do it to be competitive. They apparently can't make max of power at the same rpm, maybe because their compromised compressor can't quite match max boost pressures.

That is not the reason. They can not yet reach the elevated compression rate of mercedes. This means they have not the same quantity of air injected per cycle. In order to condact the right amount of air flow to the turbo generator the only solution is to compensate by incrementinc the rpm. Very simple. The problem is that at higher rpm the efficiency drops a little because of more energy wasted by friction and engine heat exchange. Next year they will inprove tji combustion or other tricks with the aim to increase compression ratio. This way not only peak pressure is higher but more important you increment air flow to exhausts hence tuebo

Thanks, I know a thing or 2 about tuning diesel engines but haven't really paid any attention on the development on the SI engines. Internet is a wonderful source for information but there's so much of it that sometimes it's hard to find anything useful...
It was with regard to friction loss and increased heat I wondered about the higher rpm.

[1158]

http://www.f1technical.net/forum/viewto ... ?f=4&t=445

back in the day they were doing the opposite in F1.. they were cooling the fuel for extra performance... hence the ban...

You aren't going far enough back in the day. Before fuel cooling there was fuel heating. The specific example GG mentioned can be found here:
http://www.k20a.org/upload/HondaRA168EEngine.pdf

Top of page 6 right hand side, second paragraph down begins Effect of pre-heating fuel

[godlameroso]

So do I understand this correctly? For next years engine they'll be using the fuel heater and trick-injectors
to inject fluid at a super critical state (more homogeneous), and then use TJI for combustion (later/faster/more complete)?

Honda were one of the originators of heated fuel in F1 with the RA168e. I would be surprised if they are behind other teams on this.

Temperature back then was 80*C IIRC - that is a long way from super critical. I would be worried about spontaneous ignition if you injected super critical fuel.

The pressure and temperature needed for gasoline is ~260 C and anywhere between 60-40 bar depending on fuel chemistry and a host of other factors. Both conditions can be easily reached in the combustion chamber, and fuel supply system. There are plenty of sources of heat to get the required temperature, for example the MGU-H itself runs quite hot. I suppose the devil is in the details and perhaps full on supercritical spraying isn't what's required but rather pre-conditioning the fuel so that when conditions inside the combustion chamber are correct, the desired state manifests itself.

Now there are a number of different ways to do this, not just heating and pressure, but in the fuel chemistry, and exploiting it via other means like partial electrolysis of the fuel prior to delivery to break down a certain percentage of long chain molecules. Or to promote oxygenation. There's no one magic bullet but rather the trick is in creating the eco-system that allows the fastest leanest burn with the highest exhaust density.

*Edit:
Perhaps all the other conditions exist so that the high boost pressures are the final catalyst that drives the fuel to such a state.

[ncassi22]

So do I understand this correctly? For next years engine they'll be using the fuel heater and trick-injectors
to inject fluid at a super critical state (more homogeneous), and then use TJI for combustion (later/faster/more complete)?

Honda were one of the originators of heated fuel in F1 with the RA168e. I would be surprised if they are behind other teams on this.

Temperature back then was 80*C IIRC - that is a long way from super critical. I would be worried about spontaneous ignition if you injected super critical fuel.

The pressure and temperature needed for gasoline is ~260 C and anywhere between 60-40 bar depending on fuel chemistry and a host of other factors. Both conditions can be easily reached in the combustion chamber, and fuel supply system. There are plenty of sources of heat to get the required temperature, for example the MGU-H itself runs quite hot. I suppose the devil is in the details and perhaps full on supercritical spraying isn't what's required but rather pre-conditioning the fuel so that when conditions inside the combustion chamber are correct, the desired state manifests itself.

Now there are a number of different ways to do this, not just heating and pressure, but in the fuel chemistry, and exploiting it via other means like partial electrolysis of the fuel prior to delivery to break down a certain percentage of long chain molecules. Or to promote oxygenation. There's no one magic bullet but rather the trick is in creating the eco-system that allows the fastest leanest burn with the highest exhaust density.

*Edit:
Perhaps all the other conditions exist so that the high boost pressures are the final catalyst that drives the fuel to such a state.

Ah yes thankyou for the response. I was mulling this over. I read a few articles (some focusing on gasoline as well as two stroke diesels) and it seems those are the two ways in which utilizing this phenomena can be leveraged for improved efficiency - 1 - creating a super critical environment into which fuel is injected and 2 - injecting the fuel in a super critical state to improve the homogenatiy of the mixture itself (reducing pre-ignition and allowing for later firing.)

The read from page 311 on is mighty interesting - I was really just wondering whether it was only the boost holding them back i.t.o running lean enough, or whether the fuel prep/combustion was also limiting them.

*Edit:
Upon re-reading I see you covered most of what I was wondering about As you said -"...the trick is in creating the eco-system that allows the fastest leanest burn with the highest exhaust density."

[GoranF1]

Franz Tost says 2015 Ferrari PU is 60-70hp behind Mercedes....so it seems Honda is now around 50-59 behind.....

[godlameroso]

But the Honda PU can deploy much longer than the 2015 Ferrari PU, so even if it's 20 hp down, over all it has more power since it can deploy more hybrid energy.