Honda Power Unit Hardware & Software

[Alexf1]

A possible upside to taking the extra PU elements (including a MGU-K) already in Hungary and having such a lead in both championships could be that the ERS upgrade components (ES, MGU-K and CE) can be introduced later on the car with more time available to do additional software refinements since only hardware has to be homologated on sep 1st. They can even take a current spec ES and CE in Spa (last weekend before Sep 1st) if they feel more software refinement testing can be beneficial.

[Sieper]

Or maybe this is a new spek mgu-k already and they just take ES and CE penalty free at Spa?

[Alexf1]

Or maybe this is a new spek mgu-k already and they just take ES and CE penalty free at Spa?

Yes, if the new spec MGU-K hardware functions with the software program of the current MGU-K. It seemed strange to me that after 1 PU failure they changed most of the parts of 3 PU incl the K. I'd not be that hasty if there was a new ERS coming next race. Made me think of last year where we only learned after Zandvoort that Max had gotten a new spec ES when he took his 2nd in Spa

[1158]

On the subject of the 4th PU and the penalty. I wonder if Monza would actually be a good place to take it. The dreaded DRS train never materialized in Hungary. The new cars may allow for closer following out of Parabolica (similar to what happened on Hungary) thus making DRS more effective.

[AR3-GP]

On the subject of the 4th PU and the penalty. I wonder if Monza would actually be a good place to take it. The dreaded DRS train never materialized in Hungary. The new cars may allow for closer following out of Parabolica (similar to what happened on Hungary) thus making DRS more effective.

The DRS train did materialize. Ocon ahead of Alonso ahead of Max. Max was only spared because Alonso made a mistake into T1 which let him through on the run to T2. Then Max could get Ocon because he didn't have DRS.

[1158]

On the subject of the 4th PU and the penalty. I wonder if Monza would actually be a good place to take it. The dreaded DRS train never materialized in Hungary. The new cars may allow for closer following out of Parabolica (similar to what happened on Hungary) thus making DRS more effective.

The DRS train did materialize. Ocon ahead of Alonso ahead of Max. Max was only spared because Alonso made a mistake into T1 which let him through on the run to T2. Then Max could get Ocon because he didn't have DRS.

I think Alonso would have passed Ocon. Watching the race there were several passes, not tyre offset related, into turn 1 because of the cars being able to follow closer in theblaat turn. I think we will aee aimilar results in Monza. I guess we'll have to wait and see what happens.

[ryaan2904]

In a way, because you reduce back pressure with higher turbine speed, which alters the pressure waves and how they reflect in the exhaust system. Since the H is also coupled to the compressor, compressor speed and thus intake pressure waves are altered. Furthermore, since Honda uses a bypass system compressor output can affect exhaust gas temperature and volume/density.

Do you mean that 'CAC exhaust bypass'? Can u explain please what that does?

It increases mass flow to the turbine increasing recovery potential. Instead of using a compressor bypass that vents to the atmosphere, or back into the intake plenum, it is routed to the turbine to give the turbine wheel an extra push which can then be harvested by the MGU-H. It also has the benefit of lowering the temperature of the turbine components by providing cooler air from the compressor, improving reliability of components.

The trend in aviation is to use bigger engines because it's more efficient to have big fans that move a lot of ambient temperature air at a slower velocity, than it is to have jets that move a little bit of air really fast. Likely this design consideration was absorbed into the Honda engine from their aircraft engineers. They may have figured that using an oversize compressor with a bypass and electronically controlled turbine wastegate offered interesting opportunities, seems to be paying off for them.

If the compressor keeps the engine fed, and the turbine spinning, then in effect it reduces the backpressure created by the turbine to the combustion process. Instead of absorbing crank power it's absorbing excess compressor power, which can then be harvested and used later or to save the battery the inconvenience of spooling up the turbo in places. Probably other strategies I missed, I'm just some guy.

Been a while since i last lurked here. Thanks for the answer. But I heard the engineers want the exhaust air hitting the turbine to be as energetic as possible. Wont introducing cool air cause a problem there?

[PlatinumZealot]

His idea is obviously not right.

The radial turbines used in Automotive make energy from BOTH impulse and reaction as the gas expands. Tempersture is a huge part of how they work. Material and cooling limitations limit the temperature you can pass through the turbine, but you want to retain as much temperature as you can. Especially now with these lean combustion engines retaining heat is very important.

[Tommy Cookers]

...Temperature is a huge part of how they work.... you want to retain as much temperature as you can. Especially now with these lean combustion engines retaining heat is very important.

the heat (of a given bit of gas) is its internal energy
isn't that a particular combination of temperature and pressure ? - not any combination of temperature and pressure ?

so whatever it is you want to retain 'as much temperature as you can' isn't the proper description of it ?
unless you also have eg built-in a steam engine

yes if I knew properly what I was talking about I wouldn't be asking the above question

[PlatinumZealot]

Internal energy is temperature.

Pressure is a result of that (the moving particles in gas) pushing on the container (you can remove the velocity of the fluid and the molecules should still push on the container).

Heat is the transfer of thermal energy from one body to another.

Turbines both steam and gas are advancing every year with advances in materials that can work at higher temperatures. 2nd Law of thermodynamics says there is more work to extract if you can use up more of that heat.

[gruntguru]

Internal energy is the heat energy.
Enthalpy is the heat energy plus the pressure x volume energy.

The internal energy is much larger than the pv energy.

Although the turbine is utilising pressure energy by converting it to kinetic energy, the hotter the exhaust gas, the greater its ability to convert internal energy into pv energy during the expansion process.

[Sieper]

Or maybe this is a new spek mgu-k already and they just take ES and CE penalty free at Spa?

Yes, if the new spec MGU-K hardware functions with the software program of the current MGU-K. It seemed strange to me that after 1 PU failure they changed most of the parts of 3 PU incl the K. I'd not be that hasty if there was a new ERS coming next race. Made me think of last year where we only learned after Zandvoort that Max had gotten a new spec ES when he took his 2nd in Spa

Hoping this to be the case, lets see what (if any) parts they take in Spa.

[Tommy Cookers]

Internal energy is the heat energy.
Enthalpy is the heat energy plus the pressure x volume energy
The internal energy is much larger than the pv energy.
Although the turbine is utilising pressure energy by converting it to kinetic energy, the hotter the exhaust gas, the greater its ability to convert internal energy into pv energy during the expansion process.

should I therefore believe that with temperature increase there will be pressure increase ..... ?
won't this increase the mean exhaust pressure (aka back-pressure) ... and ..... reduce the crankshaft power ?

there's quite a lot of entropic energy in the exhaust - this can't be used by expanders ?

[etusch]

If the heat increase is at TDC, if it is fast and finish as soon as possible then it is power&torque increase. And if this heat starts to cool down soon it will be easier to discharge the gas in cylinder. But this will reduce exhaust pressure to spin turbo and electric motor coupled it.
If there is heat longer during the stroke, it is beneficial for mgu-h side but brings unefficiency for ice. If I were, I would run it efficient as mush as possible during traction and as unefficient as possible during braking zones ( and if it is possible in the rules ).

[gruntguru]

Internal energy is the heat energy.
Enthalpy is the heat energy plus the pressure x volume energy
The internal energy is much larger than the pv energy.
Although the turbine is utilising pressure energy by converting it to kinetic energy, the hotter the exhaust gas, the greater its ability to convert internal energy into pv energy during the expansion process.

should I therefore believe that with temperature increase there will be pressure increase ..... ?
won't this increase the mean exhaust pressure (aka back-pressure) ... and ..... reduce the crankshaft power ?

there's quite a lot of entropic energy in the exhaust - this can't be used by expanders ?

I will quote an example of what I am trying to say. Assume we have a 100% efficient expander, 5 bar turbine inlet, 1 bar turbine outlet and a mass flow of 0.5 kg/s.

1. turbine inlet 800*K -> 148 kW and turbine outlet temp = 505*K
2. turbine inlet 1000*K -> 185 kW and turbine outlet temp = 631*K

Same pressure ratio but much higher power for hotter gas.