Honda Power Unit Hardware & Software

[Big Tea]

Correction assumes sea level. If you have 20% thinner air and want the same massflow, you need 25% more volume flow at the inlet and (ideally) a 25% bigger turbocharger.

Is the % content of air the same at all levels? For instance, is it 21% oxygen at sea level and at the height of Mexico or do heavier gasses make up more at sea level and lighter gasses more at altitude?

[GhostF1]

Correction assumes sea level. If you have 20% thinner air and want the same massflow, you need 25% more volume flow at the inlet and (ideally) a 25% bigger turbocharger.

Is the % content of air the same at all levels? For instance, is it 21% oxygen at sea level and at the height of Mexico or do heavier gasses make up more at sea level and lighter gasses more at altitude?

The actual oxygen content of air is the same at different altitude levels, it's just at a lower pressure which also means actual gas exchange is at a lower rate, so an increase in pressure ratio is all that's required to return to nominal operation. The chemistry does not change.

Also interesting that Honda traced Max's Abu Dhabi issues back to the Power Unit control unit, they lost sync to programmed maps central to Abu Dhabi and hence their generation/motoring strats.

[Big Tea]

Correction assumes sea level. If you have 20% thinner air and want the same massflow, you need 25% more volume flow at the inlet and (ideally) a 25% bigger turbocharger.

Is the % content of air the same at all levels? For instance, is it 21% oxygen at sea level and at the height of Mexico or do heavier gasses make up more at sea level and lighter gasses more at altitude?

The actual oxygen content of air is the same at different altitude levels, it's just at a lower pressure which also means actual gas exchange is at a lower rate, so an increase in pressure ratio is all that's required to return to nominal operation. The chemistry does not change.

Also interesting that Honda traced Max's Abu Dhabi issues back to the Power Unit control unit, they lost sync to programmed maps central to Abu Dhabi and hence their generation/motoring strats.

Thanks

[PlatinumZealot]

Correction assumes sea level. If you have 20% thinner air and want the same massflow, you need 25% more volume flow at the inlet and (ideally) a 25% bigger turbocharger.

Is the % content of air the same at all levels? For instance, is it 21% oxygen at sea level and at the height of Mexico or do heavier gasses make up more at sea level and lighter gasses more at altitude?

The actual oxygen content of air is the same at different altitude levels, it's just at a lower pressure which also means actual gas exchange is at a lower rate, so an increase in pressure ratio is all that's required to return to nominal operation. The chemistry does not change.

Also interesting that Honda traced Max's Abu Dhabi issues back to the Power Unit control unit, they lost sync to programmed maps central to Abu Dhabi and hence their generation/motoring strats.

Interesting. I thought these systems were all self reliant onboard the car once out of the pits. The GPS the track position stuff, lap/distance counter and the charging discharge maps. So if they lose sync to the server are you saying the charging strategy maps on the car also lose sync?

[Juzh]

Is the % content of air the same at all levels? For instance, is it 21% oxygen at sea level and at the height of Mexico or do heavier gasses make up more at sea level and lighter gasses more at altitude?

The actual oxygen content of air is the same at different altitude levels, it's just at a lower pressure which also means actual gas exchange is at a lower rate, so an increase in pressure ratio is all that's required to return to nominal operation. The chemistry does not change.

Also interesting that Honda traced Max's Abu Dhabi issues back to the Power Unit control unit, they lost sync to programmed maps central to Abu Dhabi and hence their generation/motoring strats.

Interesting. I thought these systems were all self reliant onboard the car once out of the pits. The GPS the track position stuff, lap/distance counter and the charging discharge maps. So if they lose sync to the server are you saying the charging strategy maps on the car also lose sync?

I would presume such stuff is definitely illegal. I'd say lost "sync" occurred internally somewhere in the code itself and so they had to put the car into some generic deploy/harvest mode.

[saviour stivala]

Honda insights: The power of altitude. By technical director Masamitsu Motohashi. With the power unit performing differently at altitude. It all stems from the combustion process, where fuel and oxygen are mixed at a desired ratio. The ignition of that mixture – from a spark-plug or similar – causes an explosion in the combustion chamber that forces the pistons to move and creates the power output. To get the correct ratio of air and fuel, a compressor will ensure the right amount is delivered to the combustion chamber, but this is where Mexico is unique. “At high altitude, the oxygen density is very low, so we need the compressor to work more to deliver the proper air-fuel ratio” “We have a target that we call the boost, which is the proper oxygen, we need the air to compress even more to go into the internal combustion engine. So that means the compressor working harder and more high speed”. If the compressor was working at the same level in Mexico compared to the previous race in Austin – which took place at a much lower altitude - than the result would be obvious – less power. But there are knock-on effects to having to run the components more aggressively. “We need more high-speed rotation of the compressor, and this has a big impact on reliability. Centrifugal forces have a very big impact on the compressor wheel and the turbine wheel, so it can have impact on the reliability side. On the other side it could also have an impact on performance as well, because the effect of high compressor work means the temperature of the compressed air is increased. The higher temperature can result in knocking – when there irregular timing of the combustion – So we have to reduce the power in order to avoid that”. With the majority of races taking place much closer to sea-level, there is little to be gained from designing a power unit with Mexico in mind. That means optimal performance comes down to the way the power unit is run, with special preparation taking place in the build-up to the race. The hardware side is always the same as for other tracks, so we need special calibrations for Mexico and its high altitude. This is work we do on the dyno. We replicate the Mexico conditions, so create low pressure before the air goes into the compressor. For example, so we can calibrate it under similar conditions. “The operating conditions are different, so sometimes the compressor efficiency and turbine efficiency decreases as well. So we have to check the electrical energy such as the MGU-H power and how that will be effected. The tests are not only for combustion process but also for energy management, so its a lot of preparation".

[Alexf1]

Nice piece!

[Alexf1]

Is there any info yet on what Honda has in store for spec1 (and 2) in 2020? Hope they have some more up their sleeve than just the aborted 2019 spec 5 with better mileage.

[GhostF1]

Honda insights: The power of altitude. By technical director Masamitsu Motohashi. With the power unit performing differently at altitude. It all stems from the combustion process, where fuel and oxygen are mixed at a desired ratio. The ignition of that mixture – from a spark-plug or similar – causes an explosion in the combustion chamber that forces the pistons to move and creates the power output. To get the correct ratio of air and fuel, a compressor will ensure the right amount is delivered to the combustion chamber, but this is where Mexico is unique. “At high altitude, the oxygen density is very low, so we need the compressor to work more to deliver the proper air-fuel ratio” “We have a target that we call the boost, which is the proper oxygen, we need the air to compress even more to go into the internal combustion engine. So that means the compressor working harder and more high speed”. If the compressor was working at the same level in Mexico compared to the previous race in Austin – which took place at a much lower altitude - than the result would be obvious – less power. But there are knock-on effects to having to run the components more aggressively. “We need more high-speed rotation of the compressor, and this has a big impact on reliability. Centrifugal forces have a very big impact on the compressor wheel and the turbine wheel, so it can have impact on the reliability side. On the other side it could also have an impact on performance as well, because the effect of high compressor work means the temperature of the compressed air is increased. The higher temperature can result in knocking – when there irregular timing of the combustion – So we have to reduce the power in order to avoid that”. With the majority of races taking place much closer to sea-level, there is little to be gained from designing a power unit with Mexico in mind. That means optimal performance comes down to the way the power unit is run, with special preparation taking place in the build-up to the race. The hardware side is always the same as for other tracks, so we need special calibrations for Mexico and its high altitude. This is work we do on the dyno. We replicate the Mexico conditions, so create low pressure before the air goes into the compressor. For example, so we can calibrate it under similar conditions. “The operating conditions are different, so sometimes the compressor efficiency and turbine efficiency decreases as well. So we have to check the electrical energy such as the MGU-H power and how that will be effected. The tests are not only for combustion process but also for energy management, so its a lot of preparation".

Yeah so he's saying pretty much exactly what we've discussed, although the confirmation of using more conservative timing does explain why the engine sounded a little more like it did in Singapore when it was first introduced with conservative ignition timing settings. Overly burbly, back fire crackles etc. The small mention of MGU-H power effect due to turbine efficiency decrease from impeller overspeed can be interpreted in a lot of ways, but to me, (albeit with limited understanding of how these things are run), could imply a higher energy requirement to drive the turbo faster OR an increase in the time of detachment hence a greater loss of total generation. All just thoughts.

[GhostF1]

The actual oxygen content of air is the same at different altitude levels, it's just at a lower pressure which also means actual gas exchange is at a lower rate, so an increase in pressure ratio is all that's required to return to nominal operation. The chemistry does not change.

Also interesting that Honda traced Max's Abu Dhabi issues back to the Power Unit control unit, they lost sync to programmed maps central to Abu Dhabi and hence their generation/motoring strats.

Interesting. I thought these systems were all self reliant onboard the car once out of the pits. The GPS the track position stuff, lap/distance counter and the charging discharge maps. So if they lose sync to the server are you saying the charging strategy maps on the car also lose sync?

I would presume such stuff is definitely illegal. I'd say lost "sync" occurred internally somewhere in the code itself and so they had to put the car into some generic deploy/harvest mode.

Agree, I think it was basically Control Electronics failure to be honest.

[saviour stivala]

“Yeah so he’s saying pretty much exactly what we’ve discussed”. Not only what was discussed but some more which wasn’t discussed. The aim of carry-over onto here the article right from the horse mouth was firstly as a contribution/acknowledgement in confirming the technical expertise unique to this site having expertly discussed most but not all of what the Honda technical director has elaborated upon. There are some interesting points which he elaborated on that in my opinion merits or are worthy of going into on here. An example is: “it is not worth concentrating the design efforts (hardware) on ‘Mexico like altitudes’”. On Mexico like altitudes they tune their software to make the turbo work harder, 'spins faster'. How do they make the turbo spin faster when their exhaust is weaker because of them having to prevent knocking by moving their ignition point away from optimum? How do they compensate for the weaker exhaust effects on the turbine and its powering of the ‘H’?.

[Tommy Cookers]

.....How do they make the turbo spin faster when their exhaust is weaker because of them having to prevent knocking by moving their ignition point away from optimum? How do they compensate for the weaker exhaust effects on the turbine and its powering of the ‘H’?.

afaik
the exhaust isn't weaker - it's 'stronger'
if the timing is moved to avoid detonation from (what was near sea level) the optimal there's more energy left in the exhaust
also the exhaust is 'stronger' relative to the lower ambient pressure at Mexico GP altitude

yes the greater work taken by the compressor might reduce the work recoverable by the H machine

[saviour stivala]

So the exhaust is stronger when ignition is moved away from optimum to prevent knocking (weaker combustion). Truly confusing statement. And to cap-it up, no reason as to how the exhaust is stronger is offered. Hope it is not a case of just firing an answer just for the sake of it?

[godlameroso]

So the exhaust is stronger when ignition is moved away from optimum to prevent knocking (weaker combustion). Truly confusing statement. And to cap-it up, no reason as to how the exhaust is stronger is offered. Hope it is not a case of just firing an answer just for the sake of it?

Well I imagine TC's line of thinking comes from a more complete burn in the CC leaves less heat energy for the turbine.

[saviour stivala]

Will less heat energy (exhaust) results in 'stronger' exhaust?