Honda Power Unit Hardware & Software

[Wazari]

Does this mean that MGU-H harvesting is an afterthought and more important is to focus on combustion? As that would be the damned water in your analogy?

I wouldn't say afterthought but combustion(ICE efficiency) is no less important than MGU-H harvesting if not more. Dam-compressor size, water-exhaust energy

[Talisman]

My point is this. Why have the 4 MJ and 2 MJ limits on K transfers then allow those limits to be breached by sending the energy - to the same place - by a different route? If this is happening and the FIA knows about it (and they would because it would be obvious in the data) they would ban it! It is a device/strategy designed purely to circumvent a rule. It isn't happening IMO.

Why you say that? F1 is full of examples of following the letter of the law and not the spirit of the law...Unless someone proves or hints that a specific manufacturers gains a huge advantage compared to the others I don't believe it should be banned, especially if all manufacturers do the same.

Look at it this way.

1. The FIA creates a rule to limit K to ES transfers to <2MJ/lap and ES to K transfers to <4 MJ/lap.
2. Someone comes up with the bright idea of exceeding these limits by sending the energy to a temporary storage location (the H) and almost immediately forwarding it to the (illegal) destination.
3. The FIA can monitor all these energy transfers by looking at data so they know about it.

What would the FIA do? There are only two logical options
1. Ban the "bright idea" as being outside the spirit of Rule # xxx
2. Remove Rule # xxx as being irrelevant since everybody can work around it.

The Honda engineers in the article speculate that the regulations were written deliberately by the FIA to encourage this kind of lateral thinking with a view to pushing forward MGUH development as these systems are not currently used on roadcars.

Given that the existence of this system is now in the public domain I suspect that all manufacturers are certainly aware of its existence and that they probably all employ the technology. This is backed up by Honda being the furthest behind in terms of energy regeneration at the beginning of the system yet also already at the top end of the 2MJ per lap K to ES limit indicating that the others employed other techniques for transferring more energy than that to the ES. Or perhaps there are ways of bypassing the 2MJ limit not indicated in this article.

Either way given the detailed explanation by Honda not only of the existence of this system but how it works, I suspect the FIA will ban it ASAP if your interpretation is correct.

[amho]

Some great stuff here. Unfortunately this is one area where I am definitely prohibited from speaking on specifics.

However, a few weeks ago, I attended a sailing symposium (that's a another story) and a fellow engineer from Mercedes was there. I thought he came up with a great analogy when trying to explain some of the broad parameters of the relationship between the MGU-H, K and ICE to some other sailors. He said think of an hydroelectric plant and the effect of different water levels behind the dam turning the turbines and how to maximize output of the generator at all times. Also how much electrical output would you sacrifice for the ability to refill the dam to lengthen the overall duration of output.

One thing I learned about the MGU-H, K relationship is bigger is not better and many times less is more.

In a dam when electricity output is higher than electricity demand the excess electricity is consumed to pump back the water in downstream of dam to upstream side of dam. this help for the time later that electricity demand is high...

[Craigy]

Look at it this way.
1. The FIA creates a rule to limit K to ES transfers to <2MJ/lap and ES to K transfers to <4 MJ/lap.
2. Someone comes up with the bright idea of exceeding these limits by sending the energy to a temporary storage location (the H) and almost immediately forwarding it to the (illegal) destination.
3. The FIA can monitor all these energy transfers by looking at data so they know about it.

What would the FIA do? There are only two logical options
1. Ban the "bright idea" as being outside the spirit of Rule # xxx
2. Remove Rule # xxx as being irrelevant since everybody can work around it.

Or, logical option #3, they could just let the PU manufacturers get on with it within the rules as stated, which is what they have been doing for the last 3 years and have made no noises about changing until the 2021 PU formula.

Question:
If there was a real aim at not allowing this sort of energy flow, why is the K->H route even available?
H->K is obviously useful for self-sustaining mode, I get that. What's K->H for, if not this? Why is it bidirectional?
In other words, without flywheeling, in which situation do you want to spin up the speed of the compressor+turbine using power recovered from the K?

[Tommy Cookers]

we should remember that the MGs will have by design and for various good reasons some fundamental limit of current
the MGU-K is by rule torque-limited to 200 Nm (by current limiting) so below c. 5700 crank rpm its power falls below 120 kW
it and its drive are less efficient (produce much more heat) at low rpm, best efficiency is at high rpm and lower current
and the H being subject only to design constraints can transfer more power at higher rpm

so there may be less energy available at partial ICE power than we would like to think
maybe why Honda show us K generation at full ICE power/rpm ie before the braking zone

the K rules mean that it's a constant torque machine till 5700 rpm, then a constant power/falling torque machine
the ICE is notionally (pre-map) a constant torque machine till 10500 rpm, then a constant power/falling torque machine
implying that inherent TC and ABS emulation effect from the K is larger at low rpm and particularly so at partial ICE power
varying K control modes could increase/disguise this ie give steady state/mapped behaviour hiding advantageous dynamic behaviour
ie maybe design to tolerate pole jumping at will in the K ?

[Singabule]

Some great stuff here. Unfortunately this is one area where I am definitely prohibited from speaking on specifics.

However, a few weeks ago, I attended a sailing symposium (that's a another story) and a fellow engineer from Mercedes was there. I thought he came up with a great analogy when trying to explain some of the broad parameters of the relationship between the MGU-H, K and ICE to some other sailors. He said think of an hydroelectric plant and the effect of different water levels behind the dam turning the turbines and how to maximize output of the generator at all times. Also how much electrical output would you sacrifice for the ability to refill the dam to lengthen the overall duration of output.

One thing I learned about the MGU-H, K relationship is bigger is not better and many times less is more.

In a dam when electricity output is higher than electricity demand the excess electricity is consumed to pump back the water in downstream of dam to upstream side of dam. this help for the time later that electricity demand is high...

Bigger compressor, bigger exhaust energy. Smaller turbine, with big dam, longer the duration is. Bigger turbine, more capacity but lower the duration. Water recirculation is wasting more energy than using Smaller turbine instead, that means using mguh to directly powering K is a waste, because loss in recirculation. Using very efficient engine would more beneficial than using mguh and K relation because lower net power loss. However, sometime in the night, electrical need would be very high and you dont have enough electrical energy from the turbine (outright power from PU at corner exit). In summary, create a compressor not too big, mguh not too strong, but create most efficient PU and turbo. ES and K only to blast out of corner

[Nonserviam85]

My point is this. Why have the 4 MJ and 2 MJ limits on K transfers then allow those limits to be breached by sending the energy - to the same place - by a different route? If this is happening and the FIA knows about it (and they would because it would be obvious in the data) they would ban it! It is a device/strategy designed purely to circumvent a rule. It isn't happening IMO.

Why you say that? F1 is full of examples of following the letter of the law and not the spirit of the law...Unless someone proves or hints that a specific manufacturers gains a huge advantage compared to the others I don't believe it should be banned, especially if all manufacturers do the same.

Look at it this way.

1. The FIA creates a rule to limit K to ES transfers to <2MJ/lap and ES to K transfers to <4 MJ/lap.
2. Someone comes up with the bright idea of exceeding these limits by sending the energy to a temporary storage location (the H) and almost immediately forwarding it to the (illegal) destination.
3. The FIA can monitor all these energy transfers by looking at data so they know about it.

What would the FIA do? There are only two logical options
1. Ban the "bright idea" as being outside the spirit of Rule # xxx
2. Remove Rule # xxx as being irrelevant since everybody can work around it.

Regarding 2. someone can claim that since an intermediate legal destination exist, the whole philosophy is legal. Is there a possibility that FIA didn't anticipate this energy transfer being feasible or achievable when writing the rules? Or maybe this was FIA's intention when they allowed free transfer from/to MGU-H in order to advance the technology in this area?

FIA have the tendency to ban ideas (even legal ones) if someone gets a great advantage. If everyone is doing this without great advantage (as FIA can assess by the review of the data) why ban it especially if it promotes the advance in technology in the specific area?

[wuzak]

Some great stuff here. Unfortunately this is one area where I am definitely prohibited from speaking on specifics.

However, a few weeks ago, I attended a sailing symposium (that's a another story) and a fellow engineer from Mercedes was there. I thought he came up with a great analogy when trying to explain some of the broad parameters of the relationship between the MGU-H, K and ICE to some other sailors. He said think of an hydroelectric plant and the effect of different water levels behind the dam turning the turbines and how to maximize output of the generator at all times. Also how much electrical output would you sacrifice for the ability to refill the dam to lengthen the overall duration of output.

One thing I learned about the MGU-H, K relationship is bigger is not better and many times less is more.

In a dam when electricity output is higher than electricity demand the excess electricity is consumed to pump back the water in downstream of dam to upstream side of dam. this help for the time later that electricity demand is high...

Bigger compressor, bigger exhaust energy. Smaller turbine, with big dam, longer the duration is. Bigger turbine, more capacity but lower the duration. Water recirculation is wasting more energy than using Smaller turbine instead, that means using mguh to directly powering K is a waste, because loss in recirculation. Using very efficient engine would more beneficial than using mguh and K relation because lower net power loss. However, sometime in the night, electrical need would be very high and you dont have enough electrical energy from the turbine (outright power from PU at corner exit). In summary, create a compressor not too big, mguh not too strong, but create most efficient PU and turbo. ES and K only to blast out of corner

In terms of hydro, you set your dam up with multiple turbines. And if generation is greater than demand you switch some off and/or control the flow rate through the turbines.

[dren]

Or you could look at it as how much electrical energy would you use to spool your compressor so there is no lag in getting the turbine ready for H generation. As TC stated, the output of the K is reduced at these lower RPM levels.

[dren]

One thing I learned about the MGU-H, K relationship is bigger is not better and many times less is more.

This is insinuated in the energy flow diagram for the 'Extra Harvest' mode. The H->K transfer line is there, but it is small/thin lined compared to the other energy flows. Or maybe I'm just reading too much into it.

[dren]

So, the main goal is max ICE efficiency, max MGUH generation (total energy over a lap, not peak power) which likely means less generation capacity but more often. The more total energy the H motors the K over a lap, the further your ES energy goes in supplementing the K motoring.

From the pictures several pages back, the H looks fairly small in comparison to the tiny K. It looks like it doesn't protrude much past the first bank of cylinders.

[stevesingo]

we should remember that the MGs will have by design and for various good reasons some fundamental limit of current
the MGU-K is by rule torque-limited to 200 Nm (by current limiting) so below c. 5700 crank rpm its power falls below 120 kW
it and its drive are less efficient (produce much more heat) at low rpm, best efficiency is at high rpm and lower current
and the H being subject only to design constraints can transfer more power at higher rpm

so there may be less energy available at partial ICE power than we would like to think
maybe why Honda show us K generation at full ICE power/rpm ie before the braking zone

the K rules mean that it's a constant torque machine till 5700 rpm, then a constant power/falling torque machine
the ICE is notionally (pre-map) a constant torque machine till 10500 rpm, then a constant power/falling torque machine
implying that inherent TC and ABS emulation effect from the K is larger at low rpm and particularly so at partial ICE power
varying K control modes could increase/disguise this ie give steady state/mapped behaviour hiding advantageous dynamic behaviour
ie maybe design to tolerate pole jumping at will in the K ?

How would the gearing of the MGU-K to crankshaft change this?

I would think gearing a low as possible, reducing current and therefore conductor cross section and heat would be beneficial.

[roon]

If a clutch is present, and when the compressor load and turbo power are balanced, the MGU-H could be detached during this proposed high-frequency expend-generate function, to act purely as a secondary MGU-K. Reduced rotating mass might allow higher frequency oscillations.

If the MGU-H has two stators, in-line or coaxial, the expend and generate functions could be performed simultaneously without high frequency switching. The rules do not specify MGU design features, and simply refer to it as an 'electrical machine' and an 'electrical motor generator.' Discrete 'motor' and 'generator' sections for the stator, sharing a common rotor, would be achievable. Thus the K could overdrive the motor-section of the H beyond compressor power requirements while the generator-section of the H constantly feeding the ES.

[Tommy Cookers]

regarding the ratio of the gearing from K to crankshaft imo there's no magic answer ....

I think the electrical designer had quite a free hand in choosing the K rpm (clearly not so with the H)
and favoured 30000 - 40000 rpm, so needing a gear ratio of about 3:1
if the K is idle ie just behaving as a rotating lump of metal the ICE 'feels' the K's inertia as 9 times its actual value (plus geartrain)
fully activated the K plus geartrain is imo less responsive than the ICE so is still an inertial burden to the ICE (for all gear ratios)
minimising this burden is vital to minimise effective gearshift time
without gearing the K would have needed 3x the present torque and have been a bigger and probably less responsive machine

my broader point was that the whole electrical side would be better if designed for a rather steady current
ie keeping the voltage (rpm) rather high and so avoiding high current (torque)
there's many stages of electrical energy manipulation internally heating the MG drives
and remember that ES charging and discharging tends always to need conversion to the required voltage
the whole K-related side may be intentionally unable to serve 120 kW continuously at the peak current equivalent to 5700 rpm
ie 'only' continuously 120 kW-capable at 9000-12000 rpm
making K generation at partial ICE power less than totally attractive and K generation at higher ICE power not unattractive

[ME4ME]

It says MGU-K 5000 rpm in one of the Honda images.

EDIT: Got that wrong. 50k rpm - as pointed out below.