FIA wants to ban qualifying modes in 2021

[63l8qrrfy6]

But what I am trying to say is that there can't be a big difference.
In reality even with say 10 MJ, the SOC range where the battery is efficient only gives you a limited usable capacity.

From memory there was an image posted a while ago of an ES labelled as 2.3kWh which is 8.4MJ. It isn’t clear whether this is physical capacity or working capacity.

If it is physical capacity usable capacity might be around 5MJ. This leaves only 1MJ or so to provide for efficiency losses.

If it is working capacity the physical capacity might be in the 12-14 range you suggested earlier. This would allow 4 or 5 MJ for efficiency losses over the course of a race. At 98% round trip efficiency that would allow for 3 to 4 MJ per lap charge/deploy.

I think your estimate of ES power is a little high. Mercedes say the peak is 200kW and I think the average is likely to be nearer the 120kW it supplies to the MGU-K.

Even with 200 kW peak the extra capacity afforded by reducing the specific power requirement would be tiny.
The other factor to consider is that the capacity degrades rapidly, particularly in high power cells operating at high duty cycles. So there must be some capacity overhead to account for this.

As a side note I still think we are unde-estimating the compressor power. With Miller cycle, the PR requirement is significantly higher compared to a normal cycle so the MGUH optimum power would also be higher, particularly when considering that it also has to overcome the turbo inertia. An interesting read on this:
https://library.e.abb.com/public/bb370e ... nes....pdf

[63l8qrrfy6]

Keep in mind that the overtake button used to be qualy mode with all bells and whistles.
Now it is just full deploy with no change in ICE settings.

[michl420]

Yes, didn't know that there is a energy limit for the ES. So my theory is not allowed.

[godlameroso]

But what I am trying to say is that there can't be a big difference.
In reality even with say 10 MJ, the SOC range where the battery is efficient only gives you a limited usable capacity.

From memory there was an image posted a while ago of an ES labelled as 2.3kWh which is 8.4MJ. It isn’t clear whether this is physical capacity or working capacity.

If it is physical capacity usable capacity might be around 5MJ. This leaves only 1MJ or so to provide for efficiency losses.

If it is working capacity the physical capacity might be in the 12-14 range you suggested earlier. This would allow 4 or 5 MJ for efficiency losses over the course of a race. At 98% round trip efficiency that would allow for 3 to 4 MJ per lap charge/deploy.

I think your estimate of ES power is a little high. Mercedes say the peak is 200kW and I think the average is likely to be nearer the 120kW it supplies to the MGU-K.

Even with 200 kW peak the extra capacity afforded by reducing the specific power requirement would be tiny.
The other factor to consider is that the capacity degrades rapidly, particularly in high power cells operating at high duty cycles. So there must be some capacity overhead to account for this.

As a side note I still think we are unde-estimating the compressor power. With Miller cycle, the PR requirement is significantly higher compared to a normal cycle so the MGUH optimum power would also be higher, particularly when considering that it also has to overcome the turbo inertia. An interesting read on this:
https://library.e.abb.com/public/bb370e ... nes....pdf

That's the rub, does the MGU-H have to supply enough energy to drive the compressor to any speed, or is the MGU-H working with exhaust gases and just giving a helping push? If it's only helping exhaust gases, then the MGU-H will require significantly less than 100kW to drive the compressor to full beans.

[Jolle]

From memory there was an image posted a while ago of an ES labelled as 2.3kWh which is 8.4MJ. It isn’t clear whether this is physical capacity or working capacity.

If it is physical capacity usable capacity might be around 5MJ. This leaves only 1MJ or so to provide for efficiency losses.

If it is working capacity the physical capacity might be in the 12-14 range you suggested earlier. This would allow 4 or 5 MJ for efficiency losses over the course of a race. At 98% round trip efficiency that would allow for 3 to 4 MJ per lap charge/deploy.

I think your estimate of ES power is a little high. Mercedes say the peak is 200kW and I think the average is likely to be nearer the 120kW it supplies to the MGU-K.

Even with 200 kW peak the extra capacity afforded by reducing the specific power requirement would be tiny.
The other factor to consider is that the capacity degrades rapidly, particularly in high power cells operating at high duty cycles. So there must be some capacity overhead to account for this.

As a side note I still think we are unde-estimating the compressor power. With Miller cycle, the PR requirement is significantly higher compared to a normal cycle so the MGUH optimum power would also be higher, particularly when considering that it also has to overcome the turbo inertia. An interesting read on this:
https://library.e.abb.com/public/bb370e ... nes....pdf

That's the rub, does the MGU-H have to supply enough energy to drive the compressor to any speed, or is the MGU-H working with exhaust gases and just giving a helping push? If it's only helping exhaust gases, then the MGU-H will require significantly less than 100kW to drive the compressor to full beans.

I expect that the H has enough power to do all of the compressor work on its own, so they can do (or did, before the Qmodes) to run with the waste gate fully open.

The H is probably also pretty precise, they can use it to tune the air intake to keep the mix stable (with 100l/h fuel), giving it more boost at 10.500 rpm and a bit less above. Basically keeping the amount of air per hour stable.

[henry]

I expect that the H has enough power to do all of the compressor work on its own, so they can do (or did, before the Qmodes) to run with the waste gate fully open.

The H is probably also pretty precise, they can use it to tune the air intake to keep the mix stable (with 100l/h fuel), giving it more boost at 10.500 rpm and a bit less above. Basically keeping the amount of air per hour stable.

The wastegates reduce the pressure in the exhaust they do not divert the exhaust from the turbine. Even with the wastegates fully open the turbine provides part of the Power to drive the compressor. The more power the turbine delivers in this mode the longer they can run with wastegates open and hence maximum power.

[godlameroso]

Exactly, the turbine is, contrary to popular belief, not primarily driven by gas impinging on the turbine blades, it is driven mainly by the pressure differential across the turbine. The pressure at the inlet is much higher than the exit.

[saviour stivala]

Pressure turbines;- In a turbo-supercharging installation, all cylinders exhausts into a common collector with two exit paths;- one through a variable opening waste-gate, and the other through nozzles aimed at a turbine wheel. With the waste-gate fully opened, there is no restriction, and collector pressure is nearly atmospheric. However, as the waste-gate is closed, pressure builds-up in the collector. The gas is forced through the nozzles, turning a turbine, which drives a supercharger. No power recovery is possible in such a system unless the collector is above exiting atmospheric pressure.

[hollus]

Stivala, you posted that exact text in another thread on july 26th.
Lest discussion goes in circles, I suggest to all that you consider that the same term might be used for different concepts by different people. similarly the same concept can be refered to by different names. So let's not discuss semantics, please. Much more fun to discuss actual working assemblies.

[63l8qrrfy6]

Pressure turbines;- In a turbo-supercharging installation, all cylinders exhausts into a common collector with two exit paths;- one through a variable opening waste-gate, and the other through nozzles aimed at a turbine wheel. With the waste-gate fully opened, there is no restriction, and collector pressure is nearly atmospheric. However, as the waste-gate is closed, pressure builds-up in the collector. The gas is forced through the nozzles, turning a turbine, which drives a supercharger. No power recovery is possible in such a system unless the collector is above exiting atmospheric pressure.

Last attempt to explain this:

Say the wastegate is open and turbine inlet leads to your ear.
Your ear will be able to perceive the blowdown pulse which propagates acoustically. That pulse will do work on your eardrum regardless of what the wastegate is doing. To convince yourself you can build a y pipe, place a sound source at one end, your ear against another open end and confirm that you still hear sound regardles of whether the third end is open or closed.

Secondly even if the turbine restriction is very large compared to an open waste restriction it is definitely finite which means there is massflow through the turbine. Again you can do a simple experiment with an y pipe having one small diameter outlet (turbine restriction) and one large diameter outlet (open wastegate). You can then convince yourself that as long as the small diameter outlet is finite there will be massflow out of it.

Get some pipes and have a go first before repeating the same false claims.

[Tommy Cookers]

Pressure turbines .....

turbocharged cars don't have pressure turbines - they have blowdown turbines

ie turbines that are fed exhaust pressure 'pulses' (their exhaust systems being designed to conserve 'pulses')
not turbines fed a steady raised pressure (their exhaust systems being designed to eliminate pressure 'pulses')

s-s's Wright words compare (familiar) American aircraft pressure turbine turbos with (novel) Wright turbo-compounding
aircraft turbos didn't increase power at sea level - Wright turbocompounding did increase power at sea level

the turbocharged aircraft worked well at 30000' because of the low ambient pressure
which provided (from raised mean exhaust pressure) exhaust thrust power greater than the loss in crankshaft power

[saviour stivala]

Pressure turbines;- In a turbo-supercharging installation, all cylinders exhausts into a common collector with two exit paths;- one through a variable opening waste-gate, and the other through nozzles aimed at a turbine wheel. With the waste-gate fully opened, there is no restriction, and collector pressure is nearly atmospheric. However, as the waste-gate is closed, pressure builds-up in the collector. The gas is forced through the nozzles, turning a turbine, which drives a supercharger. No power recovery is possible in such a system unless the collector is above exiting atmospheric pressure.

Last attempt to explain this:

Say the wastegate is open and turbine inlet leads to your ear.
Your ear will be able to perceive the blowdown pulse which propagates acoustically. That pulse will do work on your eardrum regardless of what the wastegate is doing. To convince yourself you can build a y pipe, place a sound source at one end, your ear against another open end and confirm that you still hear sound regardles of whether the third end is open or closed.

Secondly even if the turbine restriction is very large compared to an open waste restriction it is definitely finite which means there is massflow through the turbine. Again you can do a simple experiment with an y pipe having one small diameter outlet (turbine restriction) and one large diameter outlet (open wastegate). You can then convince yourself that as long as the small diameter outlet is finite there will be massflow out of it.

Get some pipes and have a go first before repeating the same false claims.

Your ‘’Grandstanding’’ analogy has been addressed to the wrong person. It should have been addressed to the field engineering department. Curtiss Wright corporation Wright aeronautical division technical paper and their findings about the ''facts about turbocompounding''.

[63l8qrrfy6]

Pressure turbines;- In a turbo-supercharging installation, all cylinders exhausts into a common collector with two exit paths;- one through a variable opening waste-gate, and the other through nozzles aimed at a turbine wheel. With the waste-gate fully opened, there is no restriction, and collector pressure is nearly atmospheric. However, as the waste-gate is closed, pressure builds-up in the collector. The gas is forced through the nozzles, turning a turbine, which drives a supercharger. No power recovery is possible in such a system unless the collector is above exiting atmospheric pressure.

Last attempt to explain this:

Say the wastegate is open and turbine inlet leads to your ear.
Your ear will be able to perceive the blowdown pulse which propagates acoustically. That pulse will do work on your eardrum regardless of what the wastegate is doing. To convince yourself you can build a y pipe, place a sound source at one end, your ear against another open end and confirm that you still hear sound regardles of whether the third end is open or closed.

Secondly even if the turbine restriction is very large compared to an open waste restriction it is definitely finite which means there is massflow through the turbine. Again you can do a simple experiment with an y pipe having one small diameter outlet (turbine restriction) and one large diameter outlet (open wastegate). You can then convince yourself that as long as the small diameter outlet is finite there will be massflow out of it.

Get some pipes and have a go first before repeating the same false claims.

Your ‘’Grandstanding’’ analogy has been addressed to the wrong person. It should have been addressed to the field engineering department. Curtiss Wright corporation Wright aeronautical division technical paper and their findings about the ''facts about turbocompounding''.

did you play with the pipes then ? are you convinced ?

[saviour stivala]

Pressure turbines .....

turbocharged cars don't have pressure turbines - they have blowdown turbines

ie turbines that are fed exhaust pressure 'pulses' (their exhaust systems being designed to conserve 'pulses')
not turbines fed a steady raised pressure (their exhaust systems being designed to eliminate pressure 'pulses')

s-s's Wright words compare (familiar) American aircraft pressure turbine turbos with (novel) Wright turbo-compounding
aircraft turbos didn't increase power at sea level - Wright turbocompounding did increase power at sea level

the turbocharged aircraft worked well at 30000' because of the low ambient pressure
which provided (from raised mean exhaust pressure) exhaust thrust power greater than the loss in crankshaft power

The exhaust turbine of a turbocharger is indeed a ‘pressure’ turbine. The turbosupercharger utilizes a ‘pressure’ turbine. It is basically different from a ‘blow-down’ turbine since it converts ‘blow-down’ velocity energy in manifold collector into pressure energy. This conversion to pressure energy reflects on the scavenging ability of the cylinders. And that is exactly why that only with waste-gate open and with exhaust gasses at near atmospheric pressure and the compressor being in electrical supercharging mode that maximum possible power can be extracted from the ICE.

[djones]

Looks to be another weekend post rule change where the Honda is suffering the most. Redbull must be kicking themselves hard for pushing this one. Equally the FIA will be sat wondering why they thought it would slow Mercedes down when pretty much the rest of the world knew it would either change nothing or make them faster.