Honda Power Unit Hardware & Software

[Singabule]

They must be at the very limit with combustion efficiency already.

I would say thats for turbine regeneration. For combustion, sky is the limit, however it would be maxed at about 55% TE for piston engine (thats why ICE development is not interesting in long term for manufacturers standpoint) and to achieve that level also very expensive and not worth it

[dfegan358]

What part of power unit would manufacturers deem to hold most potential for gains? I presume the battery/energy recovery and deployment has more potential gains as it’s relatively newer technology!

I am a novice when it comes to F1 power units and engines in general.

[godlameroso]

What part of power unit would manufacturers deem to hold most potential for gains? I presume the battery/energy recovery and deployment has more potential gains as it’s relatively newer technology!

I am a novice when it comes to F1 power units and engines in general.

It's just a bunch of tiny improvements over the whole power unit. Big gains came from using steel pistons as it allowed more knock, which allowed them to push the tuning. Engineering fewer losses from the AC/DC conversion, the way the MGU-H/K and control electronics talk to each other are another source of incremental gains. Removing inefficiency of the engine, for example redesigning the water pump for fewer parasitic losses, or the lubrication system(scavenge pumps, oil tanks, oil cooling), bumping up compression, developing more stable fuel, and better lubricants. As combustion efficiency improves(with new fuel delivery, combustion chamber design, and airflow from revised intake and exhaust ports, valve timing and lift tweaks), new harvesting and deployment strategies become available.

Then there's making the power unit more compact, and lighter, improving the installation for chassis balance, or to give more space for aero.

Essentially it's 400 tiny steps that add up to 4 big ones.

[mzso]

Honda is still behind, maybe not apparent over one lap, maybe not so much on this track. Nevertheless they are behind especially over a race distance. As efficiency improves, so will the race pace. Efficiency is the hardest thing to engineer besides reliability, the two big question marks for Honda this year. If they want to win they need big strides in these areas.

Efficiency, they lack efficiency, which will come as they keep developing. The good news is that reliability seems to be decent enough that they don't have to use 5 power units.

Power and efficiency is inseparable with this formula, because of the fuel flow limit. A PU can only be less powerful while being less efficient.

[gruntguru]

But at least they tripled their compressor size compared to 2014

Tripled - really? You really believe they looked at the other teams engines and said "Nah - we can do it with a turbo 1/3 that size"?

[GhostF1]

Interesting thing to think about was a problem Honda encountered in 2016.

ICE efficiency improved to the point that the exhaust gases lost energy, which in turn caused the turbo to lose efficiency which caused the MGU-H to lose efficiency which caused a battery energy shortage. This affected them to the point that Hasegawa alluded that they had a mode that intentionally ran the engine in such a way that it sacrificed ICE combustion efficiency to increase potential exhaust energy to boost up the MGU-H energy generation. Whether that was just something to increase gas density at the expense of fuel efficiency I'm not certain, he didn't elaborate on the specifics.

There is a very fine line between finding the optimal solution for both ICE and ERS efficiency or going too far towards one area.
Curious. Maybe the unique Honda rasp we hear when off throttle through corners is related. Possible they still have this "mode" that the engine switches to to increase exhaust energy for recovery of the ERS? In this formula where every millisecond of ERS regen they can find matters, it's feasible to assume that's what is happening. It also makes sense because the noise is less present on quali laps (where regen is less of a concern).

Just a thought.

[gruntguru]

I really wonder how this balance between ice efficiency and mgu-h works. Basically they went from about 30% efficient to 50% in a few years. I think about 1/2 of the exhaust losses are now harvested by mgu-h. It does mean a lot that they sometimes choose to sent more energy into the turbine rather then to increase ice efficiency itself, because the turbine's efficiency itself is only about 50%

Starting with the total heat energy available in the exhaust, the turbine extracts about 27%. This sounds bad but the maximum possible (isentropic efficiency) for a turbine at these temperatures (assume 1000*K exhaust and 300*K ambient) is only 38%. The Carnot efficiency (the "impossible" but theoretical limit) for a heat engine operating between these temperatures is 70%.

and also mhu-h and mgu-k are about 97%, so more losses.
They must be at the very limit with combustion efficiency already.

In terms of converting heat from combustion of fuel into work on the top of the piston (IMEP), they are probably over 50% out of a possible 80%. Not quite at the limit.

[gruntguru]

Interesting thing to think about was a problem Honda encountered in 2016.

ICE efficiency improved to the point that the exhaust gases lost energy, which in turn caused the turbo to lose efficiency which caused the MGU-H to lose efficiency which caused a battery energy shortage. This affected them to the point that Hasegawa alluded that they had a mode that intentionally ran the engine in such a way that it sacrificed ICE combustion efficiency to increase potential exhaust energy to boost up the MGU-H energy generation. Whether that was just something to increase gas density at the expense of fuel efficiency I'm not certain, he didn't elaborate on the specifics.

This is an anomaly created by the rules which place limits on MGUK but not MGUH recovery. Sacrificing one kW of ICE power will only increase MGUK power by a small fraction of that ie you have a net loss of efficiency/energy.

[bill shoe]

Big gains came from using steel pistons as it allowed more knock, which allowed them to push the tuning.

Is this the fundamental thing that enables a "party mode" for qualifying?

So if Renault didn't have a party mode last year it was because they were still using aluminum pistons?

[saviour stivala]

“Party mode”>>qualifying mode>>freeload mode. Extracting the maximum power output possible (in this mode) from the present power unit is the least efficient mode. This mode is mostly used in qualifying were fuel consumption and ES power are no problem. In this mode the ICE is at maximum fueling permitted (100kg/h@10500rpm), the waste-gates are opened and the compressor is in electric supercharging mode with MGU-H and MHU-K sharing ES power. The 2014 power units were designed/born with this mode (reference:- “optimal control theory and FERRARI’S turbo-electric hybrid”). The result of this design mode resulted in reliability permitting one to use this mode for longer over a lap than the other, with another whose reliability was preventing its use at all. This is of course apart from differences in actual extraction of combustion power output, the point is all present power units were designed/born with this mode.

[Bandit1216]

I don't think anyone would burn fuel when engine braking. Why waste fuel when your air pump (ice) can feed your turbo with air only. Burning fuel on engine braking to harvest though the turbo would be very inefficient.

[henry]

I don't think anyone would burn fuel when engine braking. Why waste fuel when your air pump (ice) can feed your turbo with air only. Burning fuel on engine braking to harvest though the turbo would be very inefficient.

There are two very different use cases. Qualifying and race.

In qualifying any time they can burn fuel to reduce lap time they will.

In the race they only burn sufficient fuel to achieve a race winning time. They calculate this amount before the race and continuously during it.

[saviour stivala]

The team/s with most efficient power unit will be able to also use party mode>>qualifying mode>>freeload mode sparingly in race when needed because they will be able to compensate for fuel burned by their super efficiency when they get a clear road ahead of them during a race.

[Bandit1216]

I don't think anyone would burn fuel when engine braking. Why waste fuel when your air pump (ice) can feed your turbo with air only. Burning fuel on engine braking to harvest though the turbo would be very inefficient.

There are two very different use cases. Qualifying and race.

In qualifying any time they can burn fuel to reduce lap time they will.

In the race they only burn sufficient fuel to achieve a race winning time. They calculate this amount before the race and continuously during it.

True. But when they have sufficient energy in the battery in quali, i guess the waste gate will jut be put full open to reduce pumping losses.

[Singabule]

But at least they tripled their compressor size compared to 2014

Tripled - really? You really believe they looked at the other teams engines and said "Nah - we can do it with a turbo 1/3 that size"?

Who else crazy enough to fit compressors on the V comple with 90 degree VLIM... The casing diameter at least, i know the actual airflow would be smaller than that