Honda Power Unit Hardware & Software

[gruntguru]

Suppose you make an ICE gain of 25KW, but it can give you 11KW net to the MGU-H if you 'sacrifice' the extra ICE power, would it be worth making that sacrifice?

No. Crankshaft power is the most valuable. Perhaps if it was the other way around 11kW Crank or 25 kW MGUH you would choose the MGUH (you would still end up with 23kW at the crankshaft in self sustaining mode via the unlimited H->K path)

You are right in this sense but I believe the one million dollar question is:

Is it better to have 600kW+120kW for let's say 40 sec per lap or 610kW+120kW for 30 sec? I believe this type of dilemma is the main focus on PU development.

I would say the latter. However the crank vs exhaust energy tradeoff rarely favours the turbine to that extent. Also Honda have shown that saving crankshaft energy to the ES is virtually unlimited (limited only by the 120kW limit on the MGUK) using the "extra harvest" workaround, so it doesn't matter much whether you increase crank or turbine power.

[Big Tea]

No. Crankshaft power is the most valuable. Perhaps if it was the other way around 11kW Crank or 25 kW MGUH you would choose the MGUH (you would still end up with 23kW at the crankshaft in self sustaining mode via the unlimited H->K path)

You are right in this sense but I believe the one million dollar question is:

Is it better to have 600kW+120kW for let's say 40 sec per lap or 610kW+120kW for 30 sec? I believe this type of dilemma is the main focus on PU development.

I would say the latter. However the crank vs exhaust energy tradeoff rarely favours the turbine to that extent. Also Honda have shown that saving crankshaft energy to the ES is virtually unlimited (limited only by the 120kW limit on the MGUK) using the "extra harvest" workaround, so it doesn't matter much whether you increase crank or turbine power.

What portion of a lap would the car actually be able to use the 600kw (ice) for anyway? Is it not only the top end of 'the graph', and the rest of the time the extra additional torque would be more useful?

[PlatinumZealot]

Electrical energy is a lot more efficient than combustion energy, although deployment power is limited by the MGU-K. The MGU-H is indirectly connected to the power train, power through electrical means will always be more efficient than mechanical means. Crank power is ultimately the priority as that is the prime mover as GG correctly points out.

That is not always the case.

And where do you think the MGUH energy comes from? It comes from the brakes or the engine. Ie. It is stored in a battery after many energy conversions.

For example... Electric cars right... It starts at an oil burning power plant of 60% efficiency (if you are lucky) more likely 55%, There is transmission loss on the grid, then there is step down loss 3%, then there is a charging loss of about 20%. Then a battery discharging loss of another small percent. So the overall thermal efficiency is good at 42% but not beatable by carrying your own on-board fuel and burning it right there.
You could beat the electric car overall efficiency with a good street car diesel engine and even take it further if you had some sort of MGUH on it.

[godlameroso]

Electrical energy is a lot more efficient than combustion energy, although deployment power is limited by the MGU-K. The MGU-H is indirectly connected to the power train, power through electrical means will always be more efficient than mechanical means. Crank power is ultimately the priority as that is the prime mover as GG correctly points out.

That is not always the case.

And where do you think the MGUH energy comes from? It comes from the brakes or the engine. Ie. It is stored in a battery after many energy conversions.

For example... Electric cars right... It starts at an oil burning power plant of 60% efficiency (if you are lucky) more likely 55%, There is transmission loss on the grid, then there is step down loss 3%, then there is a charging loss of about 20%. Then a battery discharging loss of another small percent. So the overall thermal efficiency is good at 42% but not beatable by carrying your own on-board fuel and burning it right there.
You could beat the electric car overall efficiency with a good street car diesel engine and even take it further if you had some sort of MGUH on it.

What I mean is that electrical energy stored in the ES is more efficient than mechanical energy extracted from burning fuel, despite any conversion. F1 cars aren't powered by external power plants while on track. In the case of F1 cars the electrical energy has fewer losses than mechanical energy. For one, little energy(much less than mechanical) is lost to resistance or friction. Would "free-wheel mode" cost more if the compressor was belt driven off the crank, or MGU-H driven?

[PlatinumZealot]

Electrical energy is a lot more efficient than combustion energy, although deployment power is limited by the MGU-K. The MGU-H is indirectly connected to the power train, power through electrical means will always be more efficient than mechanical means. Crank power is ultimately the priority as that is the prime mover as GG correctly points out.

That is not always the case.

And where do you think the MGUH energy comes from? It comes from the brakes or the engine. Ie. It is stored in a battery after many energy conversions.

For example... Electric cars right... It starts at an oil burning power plant of 60% efficiency (if you are lucky) more likely 55%, There is transmission loss on the grid, then there is step down loss 3%, then there is a charging loss of about 20%. Then a battery discharging loss of another small percent. So the overall thermal efficiency is good at 42% but not beatable by carrying your own on-board fuel and burning it right there.
You could beat the electric car overall efficiency with a good street car diesel engine and even take it further if you had some sort of MGUH on it.

What I mean is that electrical energy stored in the ES is more efficient than mechanical energy extracted from burning fuel, despite any conversion. F1 cars aren't powered by external power plants while on track. In the case of F1 cars the electrical energy has fewer losses than mechanical energy. For one, little energy(much less than mechanical) is lost to resistance or friction. Would "free-wheel mode" cost more if the compressor was belt driven off the crank, or MGU-H driven?

My analogy is good. You aren't looking at it right. The "power plant" would be the ICE itself.. and the "electric car" would be the battery. You will lose more energy going from engine to mguh to battery to the wheels, than going from engine to straight to the wheels. As I said before you cannot look on it as snapshot in time, but over the length of the lap (energy not power). How much energy do you have and where do you want to use it. The Electric car... the energy is stored and can be released on demand... and can be overall more efficient "over the lap" but in not all cases.

[godlameroso]

That is not always the case.

And where do you think the MGUH energy comes from? It comes from the brakes or the engine. Ie. It is stored in a battery after many energy conversions.

For example... Electric cars right... It starts at an oil burning power plant of 60% efficiency (if you are lucky) more likely 55%, There is transmission loss on the grid, then there is step down loss 3%, then there is a charging loss of about 20%. Then a battery discharging loss of another small percent. So the overall thermal efficiency is good at 42% but not beatable by carrying your own on-board fuel and burning it right there.
You could beat the electric car overall efficiency with a good street car diesel engine and even take it further if you had some sort of MGUH on it.

What I mean is that electrical energy stored in the ES is more efficient than mechanical energy extracted from burning fuel, despite any conversion. F1 cars aren't powered by external power plants while on track. In the case of F1 cars the electrical energy has fewer losses than mechanical energy. For one, little energy(much less than mechanical) is lost to resistance or friction. Would "free-wheel mode" cost more if the compressor was belt driven off the crank, or MGU-H driven?

My analogy is good. You aren't looking at it right. The "power plant" would be the ICE itself.. and the "electric car" would be the battery. You will lose more energy going from engine to mguh to battery to the wheels, than going from engine to straight to the wheels. As I said before you cannot look on it as snapshot in time, but over the length of the lap (energy not power). How much energy do you have and where do you want to use it. The Electric car... the energy is stored and can be released on demand... and can be overall more efficient "over the lap" but in not all cases.

Not even arguing with you, just clarifying, you have a fixed amount of energy and without the electric machines you can't get the efficiency or power from the engine. I agree that fuel is the prime mover, and improving the combustion process is the source of the most tangible gains. In addition to peak power, which is what we're talking about, there's sustained power, as you state, in certain cases it's better to use electric mode. Would the MGU-H be more important on a track like Baku, or Silverstone? I know in places with a lot of full throttle, like Shanghai the Honda engine lacks behind the others. Is the lack due to being unable to harvest enough energy from the MGU-H? Bahrain has a lot of heavy braking so plenty of chance to harvest with MGU-K and H through extra harvest, and the power seemed to be reasonable there.

If harvesting from the MGU-H is a load on the turbine, then does it not also put a load on the exhaust gases, and by extension increase back-pressure? How much power does this increased pumping load cost in terms of crank power? Granted it costs less if you have more ICE power to start, but if you can't harvest enough exhaust energy you will always be at a deployment disadvantage. Deployment isn't just for power, it also affects power delivery and corner entry.

[godlameroso]

No. Crankshaft power is the most valuable. Perhaps if it was the other way around 11kW Crank or 25 kW MGUH you would choose the MGUH (you would still end up with 23kW at the crankshaft in self sustaining mode via the unlimited H->K path)

You are right in this sense but I believe the one million dollar question is:

Is it better to have 600kW+120kW for let's say 40 sec per lap or 610kW+120kW for 30 sec? I believe this type of dilemma is the main focus on PU development.

I would say the latter. However the crank vs exhaust energy tradeoff rarely favours the turbine to that extent. Also Honda have shown that saving crankshaft energy to the ES is virtually unlimited (limited only by the 120kW limit on the MGUK) using the "extra harvest" workaround, so it doesn't matter much whether you increase crank or turbine power.

Extra harvest uses more fuel? I suppose the amount of go juice would be the limiting factor of this strategy.

[tok-tokkie]

You guys seem to be overlooking the advantage of adding extra energy when the speed is low as against when it is high.

When the car starts accelerating if you can increase that acceleration (limited by tire grip) then you gain much more than if you deploy the extra energy later (or spread it out evenly).

The graph of car speed (y) vs time (x): What you want to do is make it steeper at the start by increasing the acceleration. The integral of that graph = the area under the graph. That area is the distance covered – it increases each second. The distance is fixed by the track. So the area under the graph is fixed. The steeper the speed graph climbs the sooner the fixed area will be reached.

So the algorithm needs to take this into account & reap some energy towards the end of the straight thus slightly increasing the time taken to do this section of the track. Then deploy that harvested energy immediately the car next starts accelerating. That will shorten the time for the next section of track more than it increased the time for the preceding section of track. Some complicated trade-offs to be sorted out by the algorithm.

[aral]

I have removed several posts due to the posting of a unsubstantiated speculative rumour that has nothing to do with the topic. Please stick to topic

[lucafo]

Hi guys.
Have anyone notice if the Honda sound had changed during 2018?
I ask because Honda used to have a very specific sound since the begin and this new information about how to improve total power maximazing the MGUH recovery, maybe, could have bring some diference in engine sound during the year.
I can not imagine how to improve the combustion proccess to have a beneficit in MGUH recovery. For my basic engineer knowledge (despite quimical inovations in order to the same amount of fuel generate more gases) the only way is to keep the heat as high as possible, so the gases would expand and moves the turbine a lit bit more.

[gruntguru]

You guys seem to be overlooking the advantage of adding extra energy when the speed is low as against when it is high.

How is that relevant to the question "do you favour the crankshaft or the turbine when trading off power gains?"

[hurril]

You guys seem to be overlooking the advantage of adding extra energy when the speed is low as against when it is high.

How is that relevant to the question "do you favour the crankshaft or the turbine when trading off power gains?"

Definitely not trying to argue against you, but one way that becomes relevant is in the fact that more crankshaft power means more total power, i.e.: more initial acceleration. The tradeoff is dynamic; provided that you can get 2,5 seconds of 3% more more crank shaft power, then that might weigh in favourably to also losing 10% for 30 seconds in order that the reduced recovery be compensated with extra re-charge strategy application for the rest of the lap.

[henry]

You guys seem to be overlooking the advantage of adding extra energy when the speed is low as against when it is high.

How is that relevant to the question "do you favour the crankshaft or the turbine when trading off power gains?"

Personally I think @tok-tokkie’s point is relevant because of the additional constraints of ES SOC and MGU-K energy flow.

Specifically they have the opportunity to run electric supercharge mode at the beginning of straights. This places a heavy load on the ES, driving both H and K. The H contributes to this ability by directly charging the ES but also by reducing the load on the ES when in the next, self sustain plus, mode driving the K directly. The duration of this is controlled by K energy flow per lap and the need to charge the ES from the H.

So increased H output extends the length of time Esupercharge can be deployed. This needs to be balanced against higher crank power which would be delivered for the whole straight and also could be used to charge the ES by driving against the K.

I think in order to know which is better use of increased combustion efficiency, crank or H, would require simulations of real tracks with real car data. I don’t have these so I may be completely wrong.

I think there might be a similar trade off between turbine power available with wastegates open versus closed.

[Nonserviam85]

You guys seem to be overlooking the advantage of adding extra energy when the speed is low as against when it is high.

When the car starts accelerating if you can increase that acceleration (limited by tire grip) then you gain much more than if you deploy the extra energy later (or spread it out evenly).

The graph of car speed (y) vs time (x): What you want to do is make it steeper at the start by increasing the acceleration. The integral of that graph = the area under the graph. That area is the distance covered – it increases each second. The distance is fixed by the track. So the area under the graph is fixed. The steeper the speed graph climbs the sooner the fixed area will be reached.

So the algorithm needs to take this into account & reap some energy towards the end of the straight thus slightly increasing the time taken to do this section of the track. Then deploy that harvested energy immediately the car next starts accelerating. That will shorten the time for the next section of track more than it increased the time for the preceding section of track. Some complicated trade-offs to be sorted out by the algorithm.

You are correct but you also need to remember that the rolling resistance is proportionate to the square of speed so you need more power in higher speeds than lower speeds to accelerate.

[mzso]

You do have to sacrifice ICE power to gain MGU-H power, likewise you have to sacrifice ICE power to harvest from the MGU-K.

I doubt this is the case. Since energy storage from the K is sorely limited (I wonder why though) regen-breaking should be more than enough to collect this energy.