Honda Power Unit Hardware & Software

[godlameroso]

If you can cleverly use deployment and harvesting energy levels you can improve traction going into and out of corners. In a sense, the drivers are busier than ever having to select a different energy strategy for every section of a lap to maximize traction, and managing energy, as well as managing tires. Shows how dependent they are on the power units, as they can also make up for a crap chassis. Or make a decent chassis slow. In Honda's case it's not just the power unit that's lacking, even in the rare instances when they can actually save enough energy to fight with a Hamilton that laps an Alonso on fresh tires, he's still about .3 slower on average.

[ringo]

Well based on the regs its quite clear that the wastegate is used often ie if it is to improve the noise of the cars in the race and not just qualifying.

I can see how people from last year are slowly going from Wastegates aren't need to now creating situations where they are used. It's so funny how things are looked at in new ways because facts are slowly being revealed about these engines.

From the get go, there was no doubt in my mind that a waste gate would be required. Reason being the MGUH is a LOAD.
A wastegate acts as a CAPACITY REDUCTION . There are major differences with those two facts.
I don't even need to get into any theories about fuel and AFR. The MGUH cannot the play the role of a waste gate. All it does it absorb excess energy while increasing back-pressure as the mass flow through the turbine goes unchanged. Boost control would be a secondary effect from the MGUH loading the turbine.

A wastegate on the other hand, does not load the turbine, what is does is reduce the mass flow through the turbine thus reducing it's capacity to perform work on the common shaft which holds both compressor and MGUH.
Less mass flow, less shaft work to the compressor, hence less boost. There is your primary boost control.

The MGUH is not primary boost control, it merely saps turbine energy which would otherwise go to the compressor or to atmosphere. The drawbacks from this are increased back pressure. The positive of this is the energy that is harvested.

If the energy is not needed and the energy store is full, the MGUH cannot perform this function. If power is not required from KERS as well, the MGUH cannot perform this secondary boost control function.
So you can see there are too many factors and scenarios where the MGUH will not carry out a boost control function effectively. The factors also determine how effective and how quickly the boost can be controlled. So this is not a very dependable or very precise way of CAPACITY CONTROL.
The waste gate does a better job at that, and does it perfectly and precisely without any secondary factors to consider.

[gruntguru]

If the fluttering noise occurs when power is reduced (closing throttle) it is more likely to be a blow off valve.

[gruntguru]

Well based on the regs its quite clear that the wastegate is used often ie if it is to improve the noise of the cars in the race and not just qualifying.

I can see how people from last year are slowly going from Wastegates aren't need to now creating situations where they are used. It's so funny how things are looked at in new ways because facts are slowly being revealed about these engines.

From the get go, there was no doubt in my mind that a waste gate would be required. Reason being the MGUH is a LOAD.
A wastegate acts as a CAPACITY REDUCTION . There are major differences with those two facts.
I don't even need to get into any theories about fuel and AFR. The MGUH cannot the play the role of a waste gate. All it does it absorb excess energy while increasing back-pressure as the mass flow through the turbine goes unchanged. Boost control would be a secondary effect from the MGUH loading the turbine.

A wastegate on the other hand, does not load the turbine, what is does is reduce the mass flow through the turbine thus reducing it's capacity to perform work on the common shaft which holds both compressor and MGUH.
Less mass flow, less shaft work to the compressor, hence less boost. There is your primary boost control.

The MGUH is not primary boost control, it merely saps turbine energy which would otherwise go to the compressor or to atmosphere. The drawbacks from this are increased back pressure. The positive of this is the energy that is harvested.

If the energy is not needed and the energy store is full, the MGUH cannot perform this function. If power is not required from KERS as well, the MGUH cannot perform this secondary boost control function.
So you can see there are too many factors and scenarios where the MGUH will not carry out a boost control function effectively. The factors also determine how effective and how quickly the boost can be controlled. So this is not a very dependable or very precise way of CAPACITY CONTROL.
The waste gate does a better job at that, and does it perfectly and precisely without any secondary factors to consider.

The formula is fuel efficiency. Opening a wastegate wastes energy. The PU is designed to waste the absolute minimum energy. The design process carefully matches the turbine, compressor, piston engine, MGUH etc to avoid any situation where the wastegate would need to be opened. Boost control is primarily by MGUH. At full power the MGUK (120 kW max) is able to use all the energy produced by the MGUH so there is no need to open the wastegate, even if the ES is full.

The wastegate is massive. Way bigger than they would need for boost control. Suggests that its primary function is to reduce back pressure to zero in qualy' mode.

[Wazari]

Well based on the regs its quite clear that the wastegate is used often ie if it is to improve the noise of the cars in the race and not just qualifying.

I can see how people from last year are slowly going from Wastegates aren't need to now creating situations where they are used. It's so funny how things are looked at in new ways because facts are slowly being revealed about these engines.

From the get go, there was no doubt in my mind that a waste gate would be required. Reason being the MGUH is a LOAD.
A wastegate acts as a CAPACITY REDUCTION . There are major differences with those two facts.
I don't even need to get into any theories about fuel and AFR. The MGUH cannot the play the role of a waste gate. All it does it absorb excess energy while increasing back-pressure as the mass flow through the turbine goes unchanged. Boost control would be a secondary effect from the MGUH loading the turbine.

A wastegate on the other hand, does not load the turbine, what is does is reduce the mass flow through the turbine thus reducing it's capacity to perform work on the common shaft which holds both compressor and MGUH.
Less mass flow, less shaft work to the compressor, hence less boost. There is your primary boost control.

The MGUH is not primary boost control, it merely saps turbine energy which would otherwise go to the compressor or to atmosphere. The drawbacks from this are increased back pressure. The positive of this is the energy that is harvested.

If the energy is not needed and the energy store is full, the MGUH cannot perform this function. If power is not required from KERS as well, the MGUH cannot perform this secondary boost control function.
So you can see there are too many factors and scenarios where the MGUH will not carry out a boost control function effectively. The factors also determine how effective and how quickly the boost can be controlled. So this is not a very dependable or very precise way of CAPACITY CONTROL.
The waste gate does a better job at that, and does it perfectly and precisely without any secondary factors to consider.

You are correct. Also based on what I've seen, I do not consider the waste gate as massive. Although I am not all that familiar with the MGU-H technology, I am with turbocharging and waste gates. Also keep in mind, the waste gate's primary function is boost control and applying a brake to the turbine can be risky especially if the MGU-H were to fail. I also don't know how fast the MGU-H alone can turn down the boost, but as fast as these transmission can up and downshift, (milliseconds), if you were to go from 10,000 to 7,000 RPM in a split second, the reduced intake volume would call for instant bleed of boost that perhaps the MGU-H can't do but a waste gate can.

[NL_Fer]

Trini you are totally forgetting the fact, that these cars are running in circles and long term is only one lap.

Image Mercedes, their MGU-H is so efficient. They can run all the WOT parts of a lap, with MGU-K enabled. During a qualify lap, the ES doesn't need to be charged after the laps finished. To use more energy from the store, they cannot use MGU-K for than all WOT parts.

The only other solution is to disable the turbine and run the compressor from the ES using MGU-H

Some serious misconceptions.
1. Laps are irrelevant. The ECU doesn't care about laps for this calculation. All it needs to know is that (and this is just one example) above a certain throttle position and rpm the boost pressure will want to increase rapidly. At the beginning the waste-gate will control this. As a few cycles of the same scenario, I.e. A few corners, the ECU will recognise that the large pressure increase that was controlled by the waste-gate and instead use the MGU-H braking action to control it. This increases MGU-H recovery energy. Simple.

2. The MGU-K is not an on off switch. It is not either enabled or disabled. I wouldn't be surprised if part of their energy strategy they are running it at 100kW instead of 120kW so they could have it running for the entire length of the straight (again just an example with made up numbers). Considering that the MGU-K can only charge 2kW per lap and deploy 4kW per lap (from the ES) then I'm pretty sure they can use all the energy they can get.

3. The turbine is not disconnected. In the case you are talking about, the waste-gate opens. The back pressure that the ICE sees is reduced considerably. The MGU-H is used to turn the shaft which turns both the compressor and the turbine. The turbine is still spinning, it is just being spun by the MGU-H instead of the exhaust gasses

Wrong again, you ade thinking to much about a street cars ECU, which has to maintain itself for a whole cars lifetime, during changing states of the engine parts and different driving conditions every day.

I believe the engine techs in f1 are programming the mgu-h strategy for every race, just to create the strategy which gets thr car around the circuit as quick as possable. Running the mgu at less than 120kw is useless, the faster a car can accelerate in the beginning of a straight, the quicker it can reach the end of it, it takes the momentum over the straights full lenght.

Think of Redbull 2010-2013, they were never on top of the speedtrap lists. But were fastest through the corners, starting every straight with more momentum than the others.

it's car racing, don not forget.

And by disabling the turbine, i consider opening the waste gate as disabling or defeating it's function.

[trinidefender]

Trini you are totally forgetting the fact, that these cars are running in circles and long term is only one lap.

Image Mercedes, their MGU-H is so efficient. They can run all the WOT parts of a lap, with MGU-K enabled. During a qualify lap, the ES doesn't need to be charged after the laps finished. To use more energy from the store, they cannot use MGU-K for than all WOT parts.

The only other solution is to disable the turbine and run the compressor from the ES using MGU-H

Some serious misconceptions.
1. Laps are irrelevant. The ECU doesn't care about laps for this calculation. All it needs to know is that (and this is just one example) above a certain throttle position and rpm the boost pressure will want to increase rapidly. At the beginning the waste-gate will control this. As a few cycles of the same scenario, I.e. A few corners, the ECU will recognise that the large pressure increase that was controlled by the waste-gate and instead use the MGU-H braking action to control it. This increases MGU-H recovery energy. Simple.

2. The MGU-K is not an on off switch. It is not either enabled or disabled. I wouldn't be surprised if part of their energy strategy they are running it at 100kW instead of 120kW so they could have it running for the entire length of the straight (again just an example with made up numbers). Considering that the MGU-K can only charge 2kW per lap and deploy 4kW per lap (from the ES) then I'm pretty sure they can use all the energy they can get.

3. The turbine is not disconnected. In the case you are talking about, the waste-gate opens. The back pressure that the ICE sees is reduced considerably. The MGU-H is used to turn the shaft which turns both the compressor and the turbine. The turbine is still spinning, it is just being spun by the MGU-H instead of the exhaust gasses

Wrong again, you ade thinking to much about a street cars ECU, which has to maintain itself for a whole cars lifetime, during changing states of the engine parts and different driving conditions every day.

I believe the engine techs in f1 are programming the mgu-h strategy for every race, just to create the strategy which gets thr car around the circuit as quick as possable. Running the mgu at less than 120kw is useless, the faster a car can accelerate in the beginning of a straight, the quicker it can reach the end of it, it takes the momentum over the straights full lenght.

Think of Redbull 2010-2013, they were never on top of the speedtrap lists. But were fastest through the corners, starting every straight with more momentum than the others.

it's car racing, don not forget.

And by disabling the turbine, i consider opening the waste gate as disabling or defeating it's function.

Of course they will program the MGU-H strategy for the race. However that doesn't not mean that the ECU cannot have a learning function which will help to fine tune the energy strategy. Especially as temperatures and pressures change throughout the day. If the ECU had no method to adapt (we are talking very low single digit percentages here) then changes in temp and pressure can throw off algorithms used for that track.

On your last point it isn't so simple. Saying that is assuming that you will have that power output from the MGU-K for every lap. To deploy the maximum of 4 MJ per lap (energy from the ES) then some of that energy will have to come from the MGU-H for the simple reason that the MGU-K is only allowed to charge the ES at a rate of 2 MJ per lap.

[bergie88]

All you guys should read the paper(s) from professor Limebeer about optimal control applied to the current F1 power units. His research group is collaborating with Ferrari. You will read that for instance the control of the large number of input signals is optimized for every track and that also the grip level of the car is taken into account. Control of these power units is just very complicated, it is not so strange that the teams are struggling with it.

On the MGU-H/waste gate discussion, I think the MGU-H is too slow when it needs to control the very fast spikes in boost pressure in the compressor. Therefore the waste gate will be used, off course as short as possible since using the waste gate is wasting energy.

[Cold Fussion]

Trini you are totally forgetting the fact, that these cars are running in circles and long term is only one lap.

Image Mercedes, their MGU-H is so efficient. They can run all the WOT parts of a lap, with MGU-K enabled. During a qualify lap, the ES doesn't need to be charged after the laps finished. To use more energy from the store, they cannot use MGU-K for than all WOT parts.

The only other solution is to disable the turbine and run the compressor from the ES using MGU-H

2. The MGU-K is not an on off switch. It is not either enabled or disabled. I wouldn't be surprised if part of their energy strategy they are running it at 100kW instead of 120kW so they could have it running for the entire length of the straight (again just an example with made up numbers). Considering that the MGU-K can only charge 2kW per lap and deploy 4kW per lap (from the ES) then I'm pretty sure they can use all the energy they can get.

I would be very much surprised if the MGU-K ran at anything other than 120 kW. It's more efficient to use more power for a shorter time than to use less power for a longer time while both use the same amount of energy. If you logically extend this, the fastest you can go is to be on the traction limit 100% of the time, deploying less power puts you further way from this limit. A good example of this are the LMP1 cars, where the 919 will deploy it's ~700 hp electric motors for 2 or 3 seconds out of corners and then run the rest of the way on the the ~550 hp ICE.

The only time I could see them not using the full 120 kW would be if they're running in a self sustaining mode where only the MGU-H is powering the MGU-K with no support from the ERS.

[Jolle]

Trini you are totally forgetting the fact, that these cars are running in circles and long term is only one lap.

Image Mercedes, their MGU-H is so efficient. They can run all the WOT parts of a lap, with MGU-K enabled. During a qualify lap, the ES doesn't need to be charged after the laps finished. To use more energy from the store, they cannot use MGU-K for than all WOT parts.

The only other solution is to disable the turbine and run the compressor from the ES using MGU-H

2. The MGU-K is not an on off switch. It is not either enabled or disabled. I wouldn't be surprised if part of their energy strategy they are running it at 100kW instead of 120kW so they could have it running for the entire length of the straight (again just an example with made up numbers). Considering that the MGU-K can only charge 2kW per lap and deploy 4kW per lap (from the ES) then I'm pretty sure they can use all the energy they can get.

I would be very much surprised if the MGU-K ran at anything other than 120 kW. It's more efficient to use more power for a shorter time than to use less power for a longer time while both use the same amount of energy. If you logically extend this, the fastest you can go is to be on the traction limit 100% of the time, deploying less power puts you further way from this limit. A good example of this are the LMP1 cars, where the 919 will deploy it's ~700 hp electric motors for 2 or 3 seconds out of corners and then run the rest of the way on the the ~550 hp ICE.

The only time I could see them not using the full 120 kW would be if they're running in a self sustaining mode where only the MGU-H is powering the MGU-K with no support from the ERS.

I assume that the MGU-H, by default, push all of its energy directly into the MGU-K, the ES is only used to top it off until 120kw. Any energy from the K and H when the driver is not on the trottle, goes into the ES. This way you are very efficient worth your power (the least losses to having it stored in the ES)

[mrluke]

On your last point it isn't so simple. Saying that is assuming that you will have that power output from the MGU-K for every lap. To deploy the maximum of 4 MJ per lap (energy from the ES) then some of that energy will have to come from the MGU-H for the simple reason that the MGU-K is only allowed to charge the ES at a rate of 2 MJ per lap.

The 4MJ is pretty much irrelevant as most of the energy transfer will be MGU-h to MGU-k

[ringo]

The formula is fuel efficiency. Opening a wastegate wastes energy. The PU is designed to waste the absolute minimum energy. The design process carefully matches the turbine, compressor, piston engine, MGUH etc to avoid any situation where the wastegate would need to be opened. Boost control is primarily by MGUH. At full power the MGUK (120 kW max) is able to use all the energy produced by the MGUH so there is no need to open the wastegate, even if the ES is full.

The wastegate is massive. Way bigger than they would need for boost control. Suggests that its primary function is to reduce back pressure to zero in qualy' mode.

It's not as surface level as that. The engine is not operating under steady state. Also the PU is not designed to waste the minimum amount of energy, it's designed and programmed track to track to produce the most performance from 100Kg of fuel. We see this when the cars go in different power modes during a race.
If it was just black and white as aboslute minimum there will only be 1 mode of operation.

The design process carefully matches the turbine, compressor, piston engine, MGUH etc to avoid any situation where the wastegate would need to be opened.

The above is a very bold statement, and i don't think we know the design philosophy behind these engines. Basically you are saying that a four way performance compromise is being made, and a variable that reduces compromise is being ignored because it wastes a few grams of burnt fuel.

Let me give you an example. The car is exiting a corner on a wet track. The driver applies the throttle. The boost starts to climb and the energy store is full. Traction is limited. Are you telling me that the MGUH will attempt to control boost by sending over 100hp to the rear axle when it is not needed?
That's just one situation where you simply tie up the whole system with a cumbersome and finicky way of boost control.
Put a waste gate in the situation and you have independent and precise control over you power unit and traction.

[mrluke]

tbf you would get wheel spin and the driver would apply less throttle.

Also IIRC Renault 2014 didn't have any wastegates?

[j.yank]

Anyone with some educated guesses what is the output power of MGU-H?

[godlameroso]

Hard to say, since it's unlimited they're probably guarding the actual figures.