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Great post aleksandergreat, a few thoughts; my understanding is that the axial turbine would run at higher rpm to achieve similar efficiency? The rules limit mgu-h rpm to 125k,that would mean greater gear reduction to the mgu-h? or i guess the turbo will be clutched and the mgu-h when the clutch is engaged will provide a load significant enough to keep the mgu-h rpm under 125k? So question will there be any gearing between turbine and mgu-h?

Harvesting from gathered energy could became weaker (less inertia, less stored rotational energy)?

If my thinking is correct and the axial turbine operates at higher rpm the rotational energy would be similar or maybe higher let’s not forget that Ek proportional to angular velocity^2.

John

rjsa wrote:News are that the Gill sensor failed testing, off by up to 1.5%:

http://www.gillsensors.com/content/fuel ... ensor.html

http://www.auto-motor-und-sport.de/form ... 32974.html

1,5% would be about 9 hp according to my calculations. Would that mean anything performance wise??

EDIT: Of course that would be multiplied by 2 if one car is running 1.5% less than the allowed 27.77g/s and another running 1.5% more. So it could be up to 18 hp difference on 2 cars just because of the sensor.

I guess the point is the rules mandate 0.5%.

rjsa wrote:I guess the point is the rules mandate 0.5%.

Then there is only two options. Rewrite the regulation on sensory tolerances or find another supplier.

SBR9 wrote:Great post aleksandergreat, a few thoughts; my understanding is that the axial turbine would run at higher rpm to achieve similar efficiency? The rules limit mgu-h rpm to 125k,that would mean greater gear reduction to the mgu-h? or i guess the turbo will be clutched and the mgu-h when the clutch is engaged will provide a load significant enough to keep the mgu-h rpm under 125k? So question will there be any gearing between turbine and mgu-h?

Harvesting from gathered energy could became weaker (less inertia, less stored rotational energy)?

If my thinking is correct and the axial turbine operates at higher rpm the rotational energy would be similar or maybe higher let’s not forget that Ek proportional to angular velocity^2.

John

Yes that i had in mind. Harvesting is on one side "weaker", but then again acceleration are easier... Its depend how you flick coin...

And also could you sacrifice the overall power for better overall torque curve. If you could make even more exiting engine could teams easier adapt on different circuits like Renault in V8 era.

There are many combinations and tradeoffs with different pros/cons.

Harvesting from gathered energy could became weaker (less inertia, less stored rotational energy)?

I don't agree with this. It all depends on how you harvest the energy. You are right that with less mass you can harvest less kinetic energy. But this is not about harvesting kinetic energy. You want to harvest waste energy.

The way i see this working is that you use the MGU-H as a harvester when maximum boost is reached. You use the MGU-H as a generator to control the boost. This is why some of us including me thinks that wastegates are redundant.

So at 10.000 rpm when max fuel is allowed this rpm should be when max boost is as well. From 10.000-15.000 boost should drop to compensate for the increase in air flow the engine creates itself when increasing revs. So you brake the turbine with the MGU-H and harvest the excess energy. The rotating mass only has something to say in the time between to fixed numbers. ect. when you brake the turbine from 125.000 rpms to 100.000 rpms. The time it takes for the turbine to get from speed A to B is the time where you would be able to harvest more energy with higher mass. But i dont think the MGU-H will be used to brake the turbine like that. It will be used to maintain a surtan rpm or slightly reduce rpm after 10.000 rpm engine speed.

5.1.6 Pressure charging may only be effected by the use of a sole single stage compressor linked to a sole single stage exhaust turbine by a shaft assembly parallel to the engine crankshaft and within 25mm of the car centre line. The shaft must be designed so as to ensure that the shaft assembly, the compressor and the turbine always rotate about a common axis and at the same angular velocity, an electrical motor generator (MGU-H) may be directly coupled to it.

This excludes the dualboost compressor. It also likely kicks out axial turbines since that would be best used in a multi stage configuration. Although if you run very high backpressure, an axial turbine might not be a bad choice or no?

One of the major benefits of the dualboost unit is its low inertia, helping it spool quick. This will not be much of an issue with the MGUH attached.

Holm86 wrote:

Harvesting from gathered energy could became weaker (less inertia, less stored rotational energy)?

I don't agree with this. It all depends on how you harvest the energy. You are right that with less mass you can harvest less kinetic energy. But this is not about harvesting kinetic energy. You want to harvest waste energy.

Right, the energy is going from heat to kinetic to electric to kinetic. You don't want to store it kinetically, you want to use it kinetically via electric transmission.

The less rotational mass, the less energy required from the MGUH to control the boost, like you said.

Any idea how much the power requied to drive the turbo drops as RPM increases past 10.5k?

dren wrote:5.1.6 Pressure charging may only be effected by the use of a sole single stage compressor linked to a sole single stage exhaust turbine by a shaft assembly parallel to the engine crankshaft and within 25mm of the car centre line. The shaft must be designed so as to ensure that the shaft assembly, the compressor and the turbine always rotate about a common axis and at the same angular velocity, an electrical motor generator (MGU-H) may be directly coupled to it.

This excludes the dualboost compressor. It also likely kicks out axial turbines since that would be best used in a multi stage configuration. Although if you run very high backpressure, an axial turbine might not be a bad choice or no?

One of the major benefits of the dualboost unit is its low inertia, helping it spool quick. This will not be much of an issue with the MGUH attached.

Just because it has two impellers counter rotating doesnt mean its not single stage. As i see it this turbo is still single stage.

my guess is that it is an ordinary double-sided impeller ie single-stage
such were used in early RR jet engines, of which about 150000 were made, mostly legal and illegal copies

btw
doesn't a radial flow turbine have a less linear rpm-pressure relationship than an axial turbine ?
so its rpm needs less variation for the intended fall in 'boost' pressure with rpm rise beyond 10500 ?
and less 'spooling-up' after low power phases ?
this could be important with a 1:1 driven MGUH ?

Holm86 wrote:

dren wrote:5.1.6 Pressure charging may only be effected by the use of a sole single stage compressor linked to a sole single stage exhaust turbine by a shaft assembly parallel to the engine crankshaft and within 25mm of the car centre line. The shaft must be designed so as to ensure that the shaft assembly, the compressor and the turbine always rotate about a common axis and at the same angular velocity, an electrical motor generator (MGU-H) may be directly coupled to it.

This excludes the dualboost compressor. It also likely kicks out axial turbines since that would be best used in a multi stage configuration. Although if you run very high backpressure, an axial turbine might not be a bad choice or no?

One of the major benefits of the dualboost unit is its low inertia, helping it spool quick. This will not be much of an issue with the MGUH attached.

Just because it has two impellers counter rotating doesnt mean its not single stage. As i see it this turbo is still single stage.

Me to! And about angular velocity says also..

2014 F1 Technical Regulations 22/87 3 July 2013 wrote:5.2.4 The MGU-H must be solely mechanically linked to the exhaust turbine of a pressure charging system. This mechanical link must be of fixed speed ratio to the exhaust turbine and may be clutched.

The rotational speed of the MGU-H may not exceed 125,000rpm.

Bothered me 2 words may and fixed ratio?

In my opinioin none of rules excluded single gearing...

Some words needs extra clarification? Anyone...

Fixed ratio means that a gearing is allowed. I doesn't have to be 1:1. It could be 1:2, 1:4, 1:5 whatever you like.
Just means that only one gearing is allowed.

And may be clutched just means you choose weather you want a clutch or not.

So what if you wanted to use a planetary gear set with an electric clutch?