Honda Power Unit Hardware & Software

[Muulka]

Gone

[henry]

I meant the MGUK- the compressor will indeed take a lot less than 120 kW, while the MGUK will want to be deploying that as much as possible.

The optimal way to use the waste gate opening very much requires energy to go to driving the compressor, however- optimal is to bypass the turbine entirely. And that energy is very, very significant.

I don't think bypassing the turbine entirely is optimal. It wastes the kinetic energy in the exhaust.

Have a look at where the wastegate is on this Renault.



Last year Honda had a double wastegate plumbed internally from turbine casing to the main exhaust.
I don't recall seeing pictures of the Mercedes or Ferrari solution but I would expect them to be similar.

[Muulka]

Gone

[henry]

I meant the MGUK- the compressor will indeed take a lot less than 120 kW, while the MGUK will want to be deploying that as much as possible.

The optimal way to use the waste gate opening very much requires energy to go to driving the compressor, however- optimal is to bypass the turbine entirely. And that energy is very, very significant.

I don't think bypassing the turbine entirely is optimal. It wastes the kinetic energy in the exhaust.

Have a look at where the wastegate is on this Renault.

http://www.formula1.com/content/fom-web ... medium.jpg

Last year Honda had a double wastegate plumbed internally from turbine casing to the main exhaust.
I don't recall seeing pictures of the Mercedes or Ferrari solution but I would expect them to be similar.

The issue is that if you don't fully open the waste gate you don't get all that much more power, but you still recover less energy, so overall it's not as good. Well I say that, but certainly for one engine I know there are two different open-wastegate strategies, one which is fully open and one which opens it enough such that the net power to/from the MGUH is zero. The not fully-open one is not used terribly often; it's preferable to have it fully open for a shorter period of time

We're talking about two different things. I was talking about the route the gases take. When you said bypass I assumed you meant going around the turbine completely.

I hadn't heard about a not fully-open wastegate possibility. If I understand it this mode is a straight turbocharger with slightly less back pressure and hence a little more ICE power. I guess a downside would be less control over the compressor output than can be achieved by modulating the MGU-H. Not sure how helpful that would be or when it might usefully be deployed.

Thanks for the insight.

[gruntguru]

Just to clarify what we are talking about with "open wastegates". The object is to reduce the pressure in the cylinder during the exhaust stroke. With an open exhaust and wave tuned headers it is possible to reduce this pressure below atmospheric. Under normal full power conditions, this pressure is probably 3 bar or more - maximising turbine power for mguh recovery. This 3 bar is a work penalty on the engine - the pistons have to use some crankshaft power to pump the exhaust out. Reducing this to 1 bar will improve the BMEP by about 2 bar - almost 6% improvement on a 35 bar engine.

It is possible to make this saving while still sending some pulse energy to the turbine. The pulse energy is produced when the exhaust valve opens and there is no pumping penalty - the piston is near the end of the power stroke. There are numerous examples of exhaust turbines collecting pulse energy without restricting flow during the exhaust stroke. (eg Wright turbo-compound). I'm sure the F1 engine designers are clever enough to produce a wastegate arrangement that communicates at least some of this pulse energy to the turbine without loading the exhaust stroke.

[Tommy Cookers]

Under normal full power conditions, this pressure is probably 3 bar or more - maximising turbine power for mguh recovery. This 3 bar is a work penalty on the engine - the pistons have to use some crankshaft power to pump the exhaust out. Reducing this to 1 bar will improve the BMEP by about 2 bar - almost 6% improvement on a 35 bar engine.
It is possible to make this saving while still sending some pulse energy to the turbine. The pulse energy is produced when the exhaust valve opens and there is no pumping penalty - the piston is near the end of the power stroke. There are numerous examples of exhaust turbines collecting pulse energy without restricting flow during the exhaust stroke. (eg Wright turbo-compound). I'm sure the F1 engine designers are clever enough to produce a wastegate arrangement that communicates at least some of this pulse energy to the turbine without loading the exhaust stroke.

imo and all that ....
EDIT - afterwards removed some wrong stuff from here

a tuned length system exhausting to atmosphere reduces exhaust pressure at favoured rpm and phase by maybe half atmospheric pressure
this could even be seen as a 'pumping gain' if/when fully wastegating
but could also be seen as justifying partial-pressure wastegating via cancellation of pumping loss combined with worthwhile turbine recovery

what if there is in effect a tuned length system exhausting to a 3 bar 'atmosphere' ? (upstream and effectively seperate from the actual atmosphere)
can the tuned length system reduce exhaust pressure at favoured rpm and phase by maybe half the 3 bar 'atmospheric' pressure ?
(so emulating our boosted-f1 tuned length induction systems)

and remember that blowdown from cylinder pressure at EVO is inherently a choked process, so always losing something potentially useful
blowing down from cylinder pressure to 1 bar ambient pressure has far greater losses than so blowing down to 3 bar

[NL_Fer]

Yeah drive the compressor.

[godlameroso]

Under normal full power conditions, this pressure is probably 3 bar or more - maximising turbine power for mguh recovery. This 3 bar is a work penalty on the engine - the pistons have to use some crankshaft power to pump the exhaust out. Reducing this to 1 bar will improve the BMEP by about 2 bar - almost 6% improvement on a 35 bar engine.
It is possible to make this saving while still sending some pulse energy to the turbine. The pulse energy is produced when the exhaust valve opens and there is no pumping penalty - the piston is near the end of the power stroke. There are numerous examples of exhaust turbines collecting pulse energy without restricting flow during the exhaust stroke. (eg Wright turbo-compound). I'm sure the F1 engine designers are clever enough to produce a wastegate arrangement that communicates at least some of this pulse energy to the turbine without loading the exhaust stroke.

imo and all that ....

BMEP is calculated from measured power by treating actual output and losses as occuring 'per active rev' ie expansion and exhaust strokes
(that's why the calculation of BMEP from measured power differs according to whether the engine is a 2 stroke or a 4 stroke)

but the notional '3 bar exhaust' pumping loss as described by gg occurs over a half rev ie 1 stroke only (exhaust)
so a 35 bar BMEP engine with 3 bar exhaust pressure reduced to 1 bar will improve the BMEP by about 1 bar (averaged over the 2 strokes)
about a 3% BMEP and power improvement


a tuned length system exhausting to atmosphere reduces exhaust pressure at favoured rpm and phase by maybe half atmospheric pressure
this could even be seen as a 'pumping gain' if/when fully wastegating
but could also be seen as justifying partial-pressure wastegating via cancellation of pumping loss combined with worthwhile turbine recovery

what if there is in effect a tuned length system exhausting to a 3 bar 'atmosphere' ? (upstream and effectively seperate from the actual atmosphere)
can the tuned length system reduce exhaust pressure at favoured rpm and phase by maybe half the 3 bar 'atmospheric' pressure ?
(so emulating our boosted-f1 tuned length induction systems)

and remember that blowdown from cylinder pressure at EVO is inherently a choked process, so always losing something potentially useful
blowing down from cylinder pressure to 1 bar ambient pressure has far greater losses than so blowing down to 3 bar

Funny thing about engines, the process that drives them are so complex that I've never ever in my life seen things scale mathematically anywhere. IE doubling displacement doesn't double power etc. But I get what you're saying, and I'm just being a jerk.

[Sasha]

Facts

Honda's TC now is too small to get full benefits of Jet Injection/pre-chamber CC.That is why their ICE is so down on power.With the new CC and injectors the performance envelope is much larger with better effiency!
That is why they are moving the TC out of the V in 2017. The only question is the MB layout or the Ferrari/Renault layout.(Mclaren wants MB layout)

But they are getting max ER from this PU design.

[trinidefender]

Facts

Honda's TC now is too small to get full benefits of Jet Injection/pre-chamber CC.That is why their ICE is so down on power.With the new CC and injectors the performance envelope is much larger with better effiency!
That is why they are moving the TC out of the V in 2017. The only question is the MB layout or the Ferrari/Renault layout.(Mclaren wants MB layout)

But they are getting max ER from this PU design.

Sasha, and anybody else who may be able to answer, does the lower combustion efficiency (and resulting ICE power) mean that the exhaust has more potential energy in it allowing for greater turbine and therefore MGUH recovery?

[Sasha]

Facts

Honda's TC now is too small to get full benefits of Jet Injection/pre-chamber CC.That is why their ICE is so down on power.With the new CC and injectors the performance envelope is much larger with better effiency!
That is why they are moving the TC out of the V in 2017. The only question is the MB layout or the Ferrari/Renault layout.(Mclaren wants MB layout)

But they are getting max ER from this PU design.

Sasha, and anybody else who may be able to answer, does the lower combustion efficiency (and resulting ICE power) mean that the exhaust has more potential energy in it allowing for greater turbine and therefore MGUH recovery?

Yes, better combustion efficiency=higher ICE power without losing MGUH ER.

[bobobaba]

Which means Mc-Honda will not have tricky ignition system in this year? Which means no hope for podium at the end of the year?:(

[godlameroso]

They have it, they just can't exploit it to the fullest with the compromised turbo they're running. This is because the compressor is not capable of efficiently creating the airflow needed for the leaner combustion the CC concept allows. It's an improvement but not as significant as could be achieved with a more efficient compressor/turbine more tailored to the performance envelope of the upgrades.

Regarding the engine layout. I can see why they're waiting, Honda's packaging expertise has come on leaps and bounds over the last two years, so they can still produce a very compact power unit despite the layout. Perhaps they're debating the layout because they want to develop the chassis and the ancillaries as much as possible before ultimately choosing. The nail in the coffin would be which layout would be easier to modify individual components without having to redesign the basic architecture, and which layout would give the best weight distribution.

[NL_Fer]

I doubt if Honda wil invest in a split turbo, because it is really hard to get right and now much stronger is the 2016 Mercedes over the rest? In 2015 Ferrari was pretty close (to Merc) and the 2016 Renault is already much stronger than those 2015 engines.

I think they will copy the current Ferrari/Renault setup mgu-comp-turbine.

[gruntguru]

Under normal full power conditions, this pressure is probably 3 bar or more - maximising turbine power for mguh recovery. This 3 bar is a work penalty on the engine - the pistons have to use some crankshaft power to pump the exhaust out. Reducing this to 1 bar will improve the BMEP by about 2 bar - almost 6% improvement on a 35 bar engine.
It is possible to make this saving while still sending some pulse energy to the turbine. The pulse energy is produced when the exhaust valve opens and there is no pumping penalty - the piston is near the end of the power stroke. There are numerous examples of exhaust turbines collecting pulse energy without restricting flow during the exhaust stroke. (eg Wright turbo-compound). I'm sure the F1 engine designers are clever enough to produce a wastegate arrangement that communicates at least some of this pulse energy to the turbine without loading the exhaust stroke.

BMEP is calculated from actual output predominantly occuring 'per active rev' ie during compression and expansion strokes (that's why the calculation of BMEP from measured power differs according to whether the engine is a 2 stroke or a 4 stroke) but the notional '3 bar exhaust' pumping loss as described by gg occurs over a half rev ie 1 stroke only (exhaust) so a 35 bar BMEP engine with 3 bar exhaust pressure reduced to 1 bar will improve the BMEP by about 1 bar (averaged over the 2 strokes) about a 3% BMEP and power improvement

If that were the case, a change to the cylinder pressure during the power stroke of say 1 bar would only change the BMEP by half a bar (which is not the case). If you check the calculation of BMEP from brake output you will find a term "number of revolutions per power stroke" so a four stroke engine has double the BMEP of a two stroke at the same rpm and power.