Honda Power Unit Hardware & Software

[gruntguru]

Agree. I think they have just drawn a smooth curve through the data points (one for each stage.)

OTOH the total pressure (static plus dynamic) might increase progressively in the rotor blade section as energy is imparted but should not increase in the stator section.

Nice find BTW.

I think they can get some pressure rise in the stator section.

In the stator the static pressure rises as the dynamic pressure falls and total pressure stays constant (less small losses).
In the rotor section, the dynamic pressure rises, static pressure could rise or stay the same (depending on design) and total pressure rises.

[gruntguru]

Not likely, I'm willing to bet they stay roughly at the same position all year, they may climb to the top of the midfield by the end of the year but they just won't have the straight line speed to keep up with Ferrari or Mercedes. I think they made design decisions they can't undo until next year, and that they'll be able to craft a much better power unit. But who knows maybe I'm wrong, and McLaren take a step forward in Spain, then another in around Suzuka.

Honda would have started the season with a prediction of Mercedes power - accurate within perhaps 2 or 3 percent. They would not have entered the fray with a 15% deficit and no prospect of significantly closing that gap. If they are 128 bhp behind now, I am sure their basic design has the potential to reduce that to 50 hp or less.

The improvements will come from fine-tuning and resolution of issues that have arisen from packaging the PU in a car and operating it in the GP environment.

[wuzak]

Not likely, I'm willing to bet they stay roughly at the same position all year, they may climb to the top of the midfield by the end of the year but they just won't have the straight line speed to keep up with Ferrari or Mercedes. I think they made design decisions they can't undo until next year, and that they'll be able to craft a much better power unit. But who knows maybe I'm wrong, and McLaren take a step forward in Spain, then another in around Suzuka.

Honda would have started the season with a prediction of Mercedes power - accurate within perhaps 2 or 3 percent. They would not have entered the fray with a 15% deficit and no prospect of significantly closing that gap. If they are 128 bhp behind now, I am sure their basic design has the potential to reduce that to 50 hp or less.

The improvements will come from fine-tuning and resolution of issues that have arisen from packaging the PU in a car and operating it in the GP environment.

How much of the deficit is doe to the MGUK, which has not been run at full power as yet?

[gruntguru]

I didn't know that. Could be substantial.

[Edis]

Axial and centrifugal compressors are "rotodynamic" machines. This means they work by accelerating the air to a high velocity (kinetic energy) then convert that KE to pressure by slowing it down again in a diffuser. In broad terms the PR of each stage is limited by the velocity ratio of the outlet to inlet of the rotating part (impeller).

It is obvious immediately that a centrifugal compressor impeller has a relatively slow inlet and much higher velocity outlet - being placed much further from the axis of rotation.

Axial compressors achieve a velocity difference through blade shape. At the intake side the blades are slicing through the air as it approaches roughly axially (small tangential velocity component). As the air passes along the blade, it is turned to rotate in the same direction as the rotating impeller so it now has a large tangential velocity component in addition to its axial (flow) component. It should be clear that the potential for achieving a large velocity ratio is much less for the axial compressor. If higher pressures are required, it is necessary to slow the air down in a diffuser (stationary vanes) and repeat the process in another stage.

Do you have an equation? Based on some of the schematics shared, that may not be the case if it is, a radial compressor still has waste gates, which is to say excess pressure.

Turbomachines follow Eulers turbomachine equation. That means that the enthalpy change over a compressor can be described as:

dh = U2*C2-U1*C1

Where U2 is the blade velocity at the outlet, U1 blade velocity at the inlet, C2 tangential fluid velocity at the outlet and C1 tangential fluid velocity at inlet.

Since the radius of the inlet is smaller than the outlet on a centrifugal compressor, the blade velocity U1 is always lower than U2.

The power required by the compressor is the enthalpy change multiplied with the massflow

P = m_dot*dh

A wastegate work by reducing the power output of the turbine driving the compressor.

[godlameroso]

Maybe the compressor is a tesla turbine.

[taperoo2k]

Not likely, I'm willing to bet they stay roughly at the same position all year, they may climb to the top of the midfield by the end of the year but they just won't have the straight line speed to keep up with Ferrari or Mercedes. I think they made design decisions they can't undo until next year, and that they'll be able to craft a much better power unit. But who knows maybe I'm wrong, and McLaren take a step forward in Spain, then another in around Suzuka.

We simply do not know where Honda are relative to Mercedes until they run the Power Unit at full power, which may take a while. As the Honda work ethic on the power unit appears to be increase power a little bit at a time, study the data, fix problems, repeat. I'm guessing Honda will hit a point when they'll be able to push things harder than they have been able to so far. Opening up development on the tokens front and on McLaren's side. Then you can compare where Honda is compared to the rest.

[CountessBathory]

Based on the following assumptions...

AFR-14.7:1
VE 120%
RPM 10500

I calculate 3.1Bar absolute.

Nice post.

BTW, would you mind explaining deeper this calculations? I got a different result and I would like to know where I'm wrong.

Thanks in advance.

[FW17]

https://twitter.com/LorenzoDL83/status/ ... 7358816256

Is that a complete head change?

And that is only one token?

[wuzak]

A head change is 2 tokens.

Piston change is 2 tokens (doesn't include crown).

Combustion chamber (includes piston crown) is 3 tokens.

Injection system is also 2 tokens.

As I read it, they can't have changed the combustion chamber, as that is more than 2 tokens, It must be one of the other things, but only one.

[Mesteño]

Maybe some changes were reliability related.

[radosav]

I would take those tweets with a lot of reserve!

[Silent Storm]

Maybe it was not translated properly and he meant 2 tokens each.

[diffuser]

I would take those tweets with a lot of reserve!

Agreed , until I see it on FIA documentation....

[godlameroso]

I have a thought. Maybe the fact the Honda sounds like an off throttle blown diffuser is because they're exploiting the exhaust stream. True it won't do as much as the naturally aspirated exhaust from the exhaust blown diffuser days, but maybe they are trying to exploit the limited impact of it into what the new regulations have allowed.