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gruntguru wrote: - Although MAP is probably 3.0 bar or more at max power, the mixture at that pressure is quite lean. This means the crankshaft power will not reduce significantly at lower boosts - say 2.5 bar abs (there is still sufficient airflow to combust the entire 100kg/hr fuel limit). What I am saying is the off-throttle turbo speed required for adequate anti-lag is probably significantly lower than max power turbo rpm (100k+).

Forgive me if this is dumb for I am but a layman, but if airflow is sufficient for combustion of 100kg/hr at 2.5 bar, why carry on to 3 bar if you could just scavenge all that extra energy through the gu-h?

dren wrote:Arai comments on the Honda PU's output: http://www.autosport.com/news/report.php/id/120561

Interesting he says they are 25hp clear of Renault but 40-50hp down on Mercedes. He also says their ICE isn't as good as Ferrari. He also stated they are staying with the same tight packaging for 2016.

He must be comparing peak numbers because it is evident the Honda PU cannot sustain that output over a full lap. Even during qualifying they are left in the dust.

He's talking the ICE ONLY in my opinion.

I think it's meaningless information, at best a distraction. It's the equivalent to saying "I have the strongest left leg in the world", unfortunately you need 2 strong legs to run fast.

Nickel wrote:

gruntguru wrote: - Although MAP is probably 3.0 bar or more at max power, the mixture at that pressure is quite lean. This means the crankshaft power will not reduce significantly at lower boosts - say 2.5 bar abs (there is still sufficient airflow to combust the entire 100kg/hr fuel limit). What I am saying is the off-throttle turbo speed required for adequate anti-lag is probably significantly lower than max power turbo rpm (100k+).

Forgive me if this is dumb for I am but a layman, but if airflow is sufficient for combustion of 100kg/hr at 2.5 bar, why carry on to 3 bar if you could just scavenge all that extra energy through the gu-h?

There is lots (and lots) of discussion on this in the V6 turbo thread. Essentially, peak thermal efficiency (and therefore peak power from the 100 kg/hr fuel limit) probably occurs with a mixture somewhere between 20 and 60 percent excess air. I expect this number to increase as the teams develop their combustion technology.

Bwetween 20 and 60 percent, I would say between 10 and 80 percent to be certain?

gruntguru wrote:

Nickel wrote:

gruntguru wrote: - Although MAP is probably 3.0 bar or more at max power, the mixture at that pressure is quite lean. This means the crankshaft power will not reduce significantly at lower boosts - say 2.5 bar abs (there is still sufficient airflow to combust the entire 100kg/hr fuel limit). What I am saying is the off-throttle turbo speed required for adequate anti-lag is probably significantly lower than max power turbo rpm (100k+).

Forgive me if this is dumb for I am but a layman, but if airflow is sufficient for combustion of 100kg/hr at 2.5 bar, why carry on to 3 bar if you could just scavenge all that extra energy through the gu-h?

There is lots (and lots) of discussion on this in the V6 turbo thread. Essentially, peak thermal efficiency (and therefore peak power from the 100 kg/hr fuel limit) probably occurs with a mixture somewhere between 20 and 60 percent excess air. I expect this number to increase as the teams develop their combustion technology.

With the same engine speed and inlet channel volume, this also means higher boost pressure?

This also means that again there is a trade-off, this time between boosting the engine for more power or generating with the MGU-H, also for more power.

diffuser wrote:

dren wrote:Arai comments on the Honda PU's output: http://www.autosport.com/news/report.php/id/120561

Interesting he says they are 25hp clear of Renault but 40-50hp down on Mercedes. He also says their ICE isn't as good as Ferrari. He also stated they are staying with the same tight packaging for 2016.

He must be comparing peak numbers because it is evident the Honda PU cannot sustain that output over a full lap. Even during qualifying they are left in the dust.

He's talking the ICE ONLY in my opinion.

This is obvious I think, ERS is limited by rules so any ERS provide same peak power, no differences there between Manor and Mercedes.

Differences are related to ICE, wich looks like can´t be too big, and specially about energy recovery and max time ERS can be used at max power. That´s the point where Honda is struggling, and what makes most of the differences.


But I understand Arai, that´s the only positive thing he can say about his PU, so that´s what he says.

Problem is peak power is irrelevant, we all saw STR passing McH too easily in the straights of SPA, so it doesn´t matter if your PU provides 25 hp more, if around a lap you only can use the 160hp of the ERS for 30% of the lap while Renault uses his for 60% of the lap (percentages invented). Peak power is irrelevant, the important datum is average power used around a lap.

bergie88 wrote:

gruntguru wrote:

Nickel wrote:Forgive me if this is dumb for I am but a layman, but if airflow is sufficient for combustion of 100kg/hr at 2.5 bar, why carry on to 3 bar if you could just scavenge all that extra energy through the gu-h?

There is lots (and lots) of discussion on this in the V6 turbo thread. Essentially, peak thermal efficiency (and therefore peak power from the 100 kg/hr fuel limit) probably occurs with a mixture somewhere between 20 and 60 percent excess air. I expect this number to increase as the teams develop their combustion technology.

With the same engine speed and inlet channel volume, this also means higher boost pressure?
This also means that again there is a trade-off, this time between boosting the engine for more power or generating with the MGU-H, also for more power.

Higher boost pressure does not have a turbine recovery cost. If the exhaust back pressure is increased by the same amount, the turbine power will increase by roughly the same as the compressor power ie no change in recovery. This is for compressor and turbine efficiencies of 80%. At higher efficiencies the recovery will improve with an increase in boost and BP. This also assumes intercooling to ambient. At higher CAT the turbine recovery will improve. Thermal loading of the combustion chamber will not increase due to the additional surplus air offsetting the higher CAT.

CAT = compressed air temperature?

Translated from here...

http://www.omnicorse.it/magazine/63023/ ... ella-mgu-h


The Belgian circuit allows a good recovery of energy during braking with the MGU-K, while it is maximum exploitation of the MGU-H which recovers energy from the exhaust gases because the track is the longest and has strokes applied from full power. The best power unit will have more power, the result of a good charging of the hybrid that will save petrol. On this track the second telemetry Wintax Marelli you can recover 1,044 kJ braking with MGU-K and 3,356 kJ in acceleration with the MGU-H for a total of 4,400 kJ per lap, the highest seen so far. The contribution of the ERS performance on this circuit could be decisive as corresponds to 3 "5 per lap and can be worth up to 20 km / h top speed.

I think that really demonstrates how relient the PU is on MGU-H generation.

Boullier just confirmed what I said few posts above

From this linkThunders posted in McLaren thread:

Eric Boullier wrote:It's not just the power, the engines are very complicated in terms of energy recovery. So what I mean by this, you have an engine, which is an internal combustion engine, and an electrical power engine. If you can properly manage the energy, because we have limitations per lap, you can use both of them to maximum. At Spa, we were lacking a little bit of power on combustion engine but we can't use 100 per cent of our electrical power which means it is a big hurt for us. To give you an idea here, we can't use it on the two straight lines and not even in the full straight line. When we know, Renault and Ferrari and Mercedes use it in all the straight line, in full.

Peak power is irrelevant, it´s average power used around a lap what counts and the main weak point of Honda PU

Honda's MGU-K is either too small or too tightly packaged. Simple as that. I cannot believe they would have made that mistake after having seen Merc's.

stevesingo wrote:Translated from here...

http://www.omnicorse.it/magazine/63023/ ... ella-mgu-h


The Belgian circuit allows a good recovery of energy during braking with the MGU-K, while it is maximum exploitation of the MGU-H which recovers energy from the exhaust gases because the track is the longest and has strokes applied from full power. The best power unit will have more power, the result of a good charging of the hybrid that will save petrol. On this track the second telemetry Wintax Marelli you can recover 1,044 kJ braking with MGU-K and 3,356 kJ in acceleration with the MGU-H for a total of 4,400 kJ per lap, the highest seen so far. The contribution of the ERS performance on this circuit could be decisive as corresponds to 3 "5 per lap and can be worth up to 20 km / h top speed.

I think that really demonstrates how relient the PU is on MGU-H generation.

Great, this is exactly the information I, and I am sure others also like it, was looking for! Lets take the fastest lap of the race, Lewis Hamilton with a 1.47.2, which is 107.2 seconds. 3.356 kJ of MGU-H recovery means an average MGU-H recovery power of 3356*10^3/107.2=31.3 kW. However, the engine is not at full power during the lap. To calculate the real power of the MGU-H, does anybody know which percentage of Spa is full throttle?

Quoted from the same artical

the distance at full throttle is estimated by telemetry Wintax for 65% of the lap.

tuj wrote:Honda's MGU-K is either too small or too tightly packaged. Simple as that. I cannot believe they would have made that mistake after having seen Merc's.

How does that make any sense? The regulations limit it to 120 kW so why would you purposely make it too small?

Cold Fussion wrote:

tuj wrote:Honda's MGU-K is either too small or too tightly packaged. Simple as that. I cannot believe they would have made that mistake after having seen Merc's.

How does that make any sense? The regulations limit it to 120 kW so why would you purposely make it too small?

And the pretty good starts are a sign that the MGU-K is well able to deploy the energy at a high rate, 120kW.

I'm pretty sure that Honda's problem is the level of MGU-H harvesting, perhaps combined with insufficiently tuned harvesting and deployment algorithms.