Honda Power Unit Hardware & Software

[Dr. Acula]

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

Retarding the ignition does not convert less energy overall. It just converts less energy into usable mechanical energy because the resulting mean effective pressure is lower. But the energy can't simply vanish, so something has to get hotter when you retard the timing.

[PlatinumZealot]

“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’?.

A turbochager naturally overspeeds (runs away) once you inject fuel comensurate with the air thats going in at an increasing rate. It is like a vicious cycle. More boost. More fuel more power. More energy to the turbine. Then More boost and repeat. The fuel injected and or the boost must be controlled to prevent turbocharger overspeed.

The exhaust being weaker is not necessarily implied. But lets say it is. It is more than sufficient enough to drive the compressor. What suffers is how much energy you have left for the MGUH, which the articled did infact mention.

[saviour stivala]

“The compressor efficiency and the 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”.

[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’?.

A turbochager naturally overspeeds (runs away) once you inject fuel comensurate with the air thats going in at an increasing rate. It is like a vicious cycle. More boost. More fuel more power. More energy to the turbine. Then More boost and repeat. The fuel injected and or the boost must be controlled to prevent turbocharger overspeed.

The exhaust being weaker is not necessarily implied. But lets say it is. It is more than sufficient enough to drive the compressor. What suffers is how much energy you have left for the MGUH, which the articled did infact mention.

Yes. Fully agree with your technical explanation, and thank you for pushing the subject/discussion on the right and proper track. Was afraid from the start that was not going to happen. As you said, exhaust being ‘weak’ as a result of not optimum combustion will still over-speed the turbo if not controlled. So what they do is over-speed the turbo beyond/past its maximum designed efficiency speed to over-boost the intake and gain-back the 20 something % loss of oxygen in the air.

[PlatinumZealot]

Wait a second. I used the term overspeed differently from you.

Overspeed of a turbocharger is actually a bad thing. It is operating out if the design range and can lead to catastrophic failure. So i don't think overspeed is the right term they way you use it.

There is no need to overspeed any turbine. There is head room as you can see in the charts. Also you can see that these large compressors have a slower operating range far from the 120k rpm limit. Generally the larger the turbocharger gets the slower it spins.

For example large ABB turbochargers only need to spin at 11,000rpm to produce 4 Bars of boost. ( flow rate about 120,000kg per hour or 33kg/s). And they were loud as hell from what I remember.

[saviour stivala]

“Over-speed” Bad or good depends on the interpretation. But after all is said its over-speeding of the turbo over and above its designed maximum efficiency RPM is what they do to gain-back the missing/lost oxygen.
“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 we call 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’. We need more high speed rotation, and this have an impact on reliability”.
Yes. Big ones are real laud, I know firsthand as although ear protection is a must I carry the scars to this day in my ears.
Yes the bigger the lower the speed, and I believe that as the design objective top priority is ‘efficiency’ they would have designed for the lowest speed possible to reach their projected boost.

[gruntguru]

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?

I can confirm that retarded ignition timing increases exhaust energy available to the turbine. It is a technique that has been used for decades to bring on boost.

Later combustion means hotter exhaust gas - less energy has been extracted expanding against the piston.

It also means higher cylinder pressure at EVO so the blowdown pulse is sharper and much more energetic.

[GhostF1]

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?

I can confirm that retarded ignition timing increases exhaust energy available to the turbine. It is a technique that has been used for decades to bring on boost.

Later combustion means hotter exhaust gas - less energy has been extracted expanding against the piston.

It also means higher cylinder pressure at EVO so the blowdown pulse is sharper and much more energetic.

Agree with this.
Hasegawa in Canada 2016 on the RA616H (he was really chatty here when they introduced their new turbo design) mentioned they can run the PU in a mode where "it increases the potential exhaust energy" to assist with MGU-H generation at the expense of outright power. You could interpret this as a timing and fuelling exercise that would cause the ICE to run less efficiently but also create a hotter or more energetic flow to drive the compressor, therefore MGU-H, harder. Whether they need to use this sort of method I don't know. Maybe a fast recharge mode?

Back on point, retarding the ignition timing would have the effect of less ICE power but if mapped correctly, an increase in potential energy to drive the turbine/MGU-H, so an "extra harvest" state to generate more electrical energy.

[godlameroso]

So what if Honda has found a way to get close to having the best of both worlds? That Honda's combustion process now produces both combustion efficiency and enough turbine exhaust energy needed to keep the ERS system functioning at all times. How would you get that? Naturally increasing mechanical compression ratio is one way. To what extent would you be limited by compression ratio? The regulations stipulate that there is fixed valve timing. We've discussed the possible benefits of a hybrid Miller/Atkinson cycle style of valve timing to get away with higher geometric compression ratio.

I have to wonder how close the current teams are to the current 18:1 limit. IIRC the limit was lower in previous seasons.

[saviour stivala]

“We have a target that we call 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’. But there are knock-on effects to having to run the compressor more aggressively. We need ‘more high-speed rotation’ of the compressor, and this has a big 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 - so we have to ‘reduce the power’ in order to avoid that”. Logic leads me to ask, how does having to reduce the power will lead to higher energy exhaust/stronger exhaust?.

[saviour stivala]

So what if Honda has found a way to get close to having the best of both worlds? That Honda's combustion process now produces both combustion efficiency and enough turbine exhaust energy needed to keep the ERS system functioning at all times. How would you get that? Naturally increasing mechanical compression ratio is one way. To what extent would you be limited by compression ratio? The regulations stipulate that there is fixed valve timing. We've discussed the possible benefits of a hybrid Miller/Atkinson cycle style of valve timing to get away with higher geometric compression ratio.

I have to wonder how close the current teams are to the current 18:1 limit. IIRC the limit was lower in previous seasons.

In my personal opinion Honda is being over flattered by the chassis it pushes forward at high altitude like Mexico. A hell of a lot more than Renault was when it was pushing the same make of chassis. (it was the same arguments back then with Renault and the same claimed achievements, just not so concentrated-on like it is now because that was Renault and not Honda). The miracle power attributed to have been found by Honda at high altitude was made mincemeat off by the power of FERRARI on the two straights at that same high altitude track.

[Tommy Cookers]

....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 - so we have to ‘reduce the power’ in order to avoid that”. Logic leads me to ask, how does having to reduce the power will lead to higher energy exhaust/stronger exhaust?.

slightly retarding the ignition is used to prevent the knocking (that would otherwise be caused by the higher charge temperature)

'sea-level' F1 turns c.50% of fuel heat into in-cylinder work and dumps c.20% to coolants - so only c.30% is in exhaust
if the ignition was retarded further enough there would be only a very small conversion of heat to work in-cylinder
so small that the crankshaft would rotate at 10500 rpm etc only if no power was taken from it to drive the car
in this condition the exhaust energy would be maximal - much higher than in F1
because little of the fuel heat is turned into work more of the fuel heat is in the exhaust

such 'free piston' engines have been and currently are made and sold
ok they don't have actual crankshafts - but their example is valid

[godlameroso]

So what if Honda has found a way to get close to having the best of both worlds? That Honda's combustion process now produces both combustion efficiency and enough turbine exhaust energy needed to keep the ERS system functioning at all times. How would you get that? Naturally increasing mechanical compression ratio is one way. To what extent would you be limited by compression ratio? The regulations stipulate that there is fixed valve timing. We've discussed the possible benefits of a hybrid Miller/Atkinson cycle style of valve timing to get away with higher geometric compression ratio.

I have to wonder how close the current teams are to the current 18:1 limit. IIRC the limit was lower in previous seasons.

In my personal opinion Honda is being over flattered by the chassis it pushes forward at high altitude like Mexico. A hell of a lot more than Renault was when it was pushing the same make of chassis. (it was the same arguments back then with Renault and the same claimed achievements, just not so concentrated-on like it is now because that was Renault and not Honda). The miracle power attributed to have been found by Honda at high altitude was made mincemeat off by the power of FERRARI on the two straights at that same high altitude track.

I think Ferrari's engine is at a similar level to Mercedes and Honda is still behind, but the closest they've been so far. Unless both Mercedes and Ferrari take a solid step over the winter, Honda has a good chance to close that gap further and may actually overtake them towards the end of the year. I doubt that the manufacturers will stand still, but if they don't take the necessary steps they may have a cause for concern.

[Wouter]

I think Ferrari's engine is at a similar level to Mercedes and Honda is still behind, but the closest they've been so far.
Unless both Mercedes and Ferrari take a solid step over the winter, Honda has a good chance to close that gap further
and may actually overtake them towards the end of the year.

I think that will be at the beginning of the season with spec 1 or at the latest with spec 2.

[saviour stivala]

I think Ferrari's engine is at a similar level to Mercedes and Honda is still behind, but the closest they've been so far.
Unless both Mercedes and Ferrari take a solid step over the winter, Honda has a good chance to close that gap further
and may actually overtake them towards the end of the year.

I think that will be at the beginning of the season with spec 1 or at the latest with spec 2.

So next season it will be more of the same, they will start with either specification one or specification two. Will they be using on average six engines per car over the season again?