Mercedes Power Unit Hardware & Software

[PlatinumZealot]

50bhp from the fuel alone in one season! That puts the efficiency calculations into perspective. Previously I mentioned that the fuel would have improved from the 1662bhp value Andy Cowell (or Paddy Lowe) mentioned a few years ago, but I didn't think it was as significant as you have stated.

No doubt an improved heating value would account for some of the 50hp and of course that portion does not improve the thermal efficiency of the ICE. Some of the gains would also be enhancements to other fuel properties such as octane rating, ignition point, latent heat of vaporisation etc etc.

Considering the sheer scale of performance growth stemming from fuel alone, I wonder what sort of gains are being seen from hardware/combustion redesign?

They work hand in hand. The fuel allows more aggressive designs in the chamber. F1 is always on the limit.

[FW17]

Not sure if this has been posted before..............

(layout in the the project 1)
In the F1 car the intercooler would be placed closer to exit of the compressor with a longer charge air piping
The air intake into the compressor also will be straight from the top

[atanatizante]

... Some of the gains would also be enhancements to other fuel properties such as octane rating, ignition point, latent heat of vaporization etc etc.

Due to regulations octane rating must be the same we found at each petrol station. Thus must be 98 max. ...
Now from my understanding fuel companies involved in F1 are focused in this turbo hybrid era into 2 development paths : one is to increase fuel calorific value but having the same octane number and the other is to decrease engine knocking leading to increase the compression hence horse power output. The first path could be done with better fuel formulations and the latter with the help of some nano-particles. These particles represents those 0.5% from the fuel that companies have no restrictions imposed by the rules ...

Sorry if this is off topic and maybe someone could guide me through, but I have a misunderstanding regarding MGU-H role in the PU. From my knowledge, MGU-H could harvest ERS at the limit of 4MJ per lap and also has no limit to deliver electric power towards MGU-K at any time on the lap. Furthermore the rules states "ERS could deploy max. 160HP for 33 sec during a lap" then these are my following questions :
1. If a lap track has let`s say 90 sec are they allowed to use 160HP for 33 sec and then 159HP for the rest of 57 sec?
2. And also, had I`m not wrong, the same rules says that MGU-K has no power limit to deliver towards driveshaft, then had they could do it, are they allowed to deliver let`s say 200HP coming out from MGU-H towards MGU-K?

[AJI]

Due to regulations octane rating must be the same we found at each petrol station. Thus must be 98 max. ...

There is no max octane rating on F1 fuel

...
1. If a lap track has let`s say 90 sec are they allowed to use 160HP for 33 sec and then 159HP for the rest of 57 sec?
2. And also, had I`m not wrong, the same rules says that MGU-K has no power limit to deliver towards driveshaft, then had they could do it, are they allowed to deliver let`s say 200HP coming out from MGU-H towards MGU-K?

1. 120kW (161hp) x 33.333 seconds = 4MJ, which is the max ERS SoC difference allowed. If they can get direct H-K transfer for the remaining seconds of the lap the only limit is the 120kW of the K.
2. See the second part of answer 1.

If you want to fry your brain tune into the Honda PU thread. The last few days have seen some pretty interesting discussion on this topic.

[atanatizante]

...
If you want to fry your brain tune into the Honda PU thread. The last few days have seen some pretty interesting discussion on this topic.

Thanx dude for your clarifications! But I have one more question : in the above mentioned AMuS article they said Merc PU has 949HP which is the powerful PU from all manufacturers. Then they also stated that their MGU-H is so good that it could deliver electric power to MGU-K for the entire lap, had I`m not get this wrong. So my question is : Merc PU has that top end power for the entire lap or in other words their MGU-H is so developed/powerful that it could sustain both harvesting the ERS and to deliver for the remaining time in every second 120kW to the MGU-K? And a additional one (sorry:) ... ). In harvest mode, it`s allowed that MGU-H could deliver electric power both for ERS and MGU-K in the same time?

[dren]

It's possible that the H could both deliver 120kw to the MGUK and also supply the ES, but it's unlikely.

[godlameroso]

Total theoretical power in the exhaust is ~400kw, the turbomachinery can convert roughly 40% of that into mechanical energy, or ~160kw it takes nearly 100kw of power to produce the pressure ratios these cars run at. This leaves roughly 60kw of energy that the MGU-H can harvest. Of course improving the efficiency of the electric motors and the turbomachinery helps this number.

You can't cheat physics, there's no free lunch. Crankshaft power is probably limited to ~640kw as an upper limit. So anything over the 60kw the MGU-H can harvest would cost you crank power. Now whether that's a worthwhile investment is what we're trying to figure out.

Afterall the turbomachinery on its own is stealing crank power in order to produce boost pressure, the ERS is essentially a fuel accumulator, it converts chemical exothermic reactions to electrochemical reactions. Again improving the electrochemical reaction will help the whole process.

Thinking about it, the investment is worth it if your energy cells can take the charge rate and have enough capacity, because ultimately you can charge the ERS at a max rate of 120kw + whatever the MGU-H can put in.

[AJI]

Thanx dude for your clarifications! But I have one more question : in the above mentioned AMuS article they said Merc PU has 949HP which is the powerful PU from all manufacturers. Then they also stated that their MGU-H is so good that it could deliver electric power to MGU-K for the entire lap, had I`m not get this wrong. So my question is : Merc PU has that top end power for the entire lap or in other words their MGU-H is so developed/powerful that it could sustain both harvesting the ERS and to deliver for the remaining time in every second 120kW to the MGU-K? And a additional one (sorry:) ... ). In harvest mode, it`s allowed that MGU-H could deliver electric power both for ERS and MGU-K in the same time?

My question is; how exactly does AMuS know this?
The only info we have (which is stuff released by HPP which we have to accept on blind faith, and various sources for GPS data) is that their fuel has 1240kW of energy available (in 2015) and that HPP report having achieved 50% TE (in 2017). That coupled with the fact that the K is limited to a max output of 120kW give us the power figures.
So, 620kW from the ICE and 120kW from the K give us 740kW. Calculate that however you want to convert to hp, but using hp(i) for the ICE and hp(e) for the K seems reasonable. That gives us a total HP number of 992hp by my basic calcs (maybe someone can check my 'back of the napkin' maths?).
I guess you could say 992hp is full tilt 'quali mode', so 949hp for race mode is not unreasonable.

The stuff we don't know is the real head scratcher, such as:
- Is that 50% TE with the compressor running in full electric mode? We have to assume yes...
- Is the 1240kW fuel number current? Doubtful...
- Is there some truly tricky stuff going on with K-H-ES-H-K transfers? Who knows?!!
- Can the K really sustain 100% duty for the whole race? Doubtful.
- How much power can the H recover?
- How long can the ICE be run at '11'?
etc, etc, etc...

All of the above is why I love this engine formula.

[Maritimer]

Weren't they using chilled air on the dyno to get 50%? The first few releases I read surrounding that said it was achieved in such a way that it wouldn't be matched in the real world.

[AJI]

Weren't they using chilled air on the dyno to get 50%? The first few releases I read surrounding that said it was achieved in such a way that it wouldn't be matched in the real world.

I'm not sure, but the thing that made me raise an eyebrow was that apparently there was a bet at HPP, and the bet was 50% TE by someone's 50th birthday. When you set a target like that it is always 'achieved' one way or another... When the marketing department want a result the best way to achieve that result is to announce it...

[Maritimer]

I'm not sure, but the thing that made me raise an eyebrow was that apparently there was a bet at HPP, and the bet was 50% TE by someone's 50th birthday. When you set a target like that it is always 'achieved' one way or another... When the marketing department want a result the best way to achieve that result is to announce it...

I found my source, it was a video put out by the team on YouTube. The only mention of cooler air is in relation to the engine's environment in the vehicle itself I guess. Says they could achieve the greater than 50% they claim, but the drag penalty made it not worth pursuing.

[PlatinumZealot]

Normally engines are benchmarked at standard conditions. That would like 20 degrees celcius, 1 atmoshphere and low humidity (i forgot the number) these sorts of conditions are not what you see at the track. Also the fluid temepratures are greatly controlled too. And they can run whatever designer fuel and lubricant they want on the dyno just for the hell of it.

[AJI]

Normally engines are benchmarked at standard conditions. That would like 20 degrees celcius, 1 atmoshphere and low humidity (i forgot the number) these sorts of conditions are not what you see at the track. Also the fluid temepratures are greatly controlled too. And they can run whatever designer fuel and lubricant they want on the dyno just for the hell of it.

I guess they would do all of the above if they're chasing numbers, which it sounds like they were, but it seems like a pointless exercise when you're building an engine to race in such a hostile environment.

Interestingly, this quite specific rule comes in for 2018:

"5.6.8 Engine plenum (as defined in line 4 of Appendix 2 to these regulations) air temperature must be more than ten degrees centigrade above ambient temperature. When assessing compliance, the temperature of the air will be the lap average recorded, by an FIA approved and sealed sensor located in an FIA approved location situated in the engine plenum, during every lap of the race. The first lap of the race, laps carried out whilst the safety car is deployed, pit in and out laps and any laps that are obvious anomalies (as judged by the technical delegate) will not be used to assess the average temperature. The ambient temperature will be that recorded by the FIA appointed weather service provider one hour before any practice session or two hours before the race. This information will also be displayed on the timing monitors."

[Zynerji]

Wait. They are limiting intercooling maximums now?

SMH

[bill shoe]

Interestingly, this quite specific rule comes in for 2018:

"5.6.8 Engine plenum (as defined in line 4 of Appendix 2 to these regulations) air temperature must be more than ten degrees centigrade above ambient temperature. When assessing compliance, the temperature of the air will be the lap average recorded, by an FIA approved and sealed sensor located in an FIA approved location situated in the engine plenum, during every lap of the race. The first lap of the race, laps carried out whilst the safety car is deployed, pit in and out laps and any laps that are obvious anomalies (as judged by the technical delegate) will not be used to assess the average temperature. The ambient temperature will be that recorded by the FIA appointed weather service provider one hour before any practice session or two hours before the race. This information will also be displayed on the timing monitors."

Weird rule on surface since we don't know what the underlying intention is. Has effect of preventing running wide-open throttle but naturally aspirated (in which case intake plenum air would be = ambient), or running large portions of the lap with throttle closed (this reduces plenum pressure so reduces temp inside it compared to ambient. And yes I know these engines may not have anything that resembles a conventional throttle, or at least not a throttle that responds in a relatively conventional way relative to torque demand.

Maybe engines were using the throttle as a kind of secondary air cooler (intercooler being the first). Or maybe related to the burn-oil-boost-power thing.