2014-2020 Formula One 1.6l V6 turbo engine formula

[gruntguru]

850hp from the ICE?

I assume that’s supercharged not turbocharged. In which case is it really ICE given that the energy to boost the charge is externally sourced? Ditto, especially, bsfc.

I think Mercedes is close to those numbers in self sustaining mode ie no ES draw.

[OO7]

There's a rising fuel rate until 10,500 rpm, I don't think they run the same boost at all RPM's nor do I believe they run constant fuel rate, nor do I think MGU-H works all that much in motor mode. The MGU-H only works to kick start the turbo, ideal boost for a given engine speed could be achieved with as little as 30kW from the MGU-H, the exhaust energy does the bulk of the work. At peak engine torque there's easily 120kw for the turbine in the form of exhaust energy. Turbos are positive feedback devices, the more energy you put in the turbine, the more boost you make which gives you even more turbine energy.

Hmm clearly these cars have blow off valves, I wonder if the boost is sent to the atmosphere or re-introduced into the air box.

The turbine isn't able to extract 120kW from the exhaust, if it were there would be little need to made energy around a lap and they PU would never de-rate.

[henry]

imo
shifting eg upshifts is done by timed defueling for c.20 milliseconds to detorque the dogs for the shift
the K is for c.20 milliseconds at full generation (demand) to contribute the best it can to slowing the PU to speed the shift

similarly for downshifts the K is at full motoring demand to contribute its bit to speed up the PU
the fuel is cut for milliseconds to detorque the dogs and then brought back in to increase the PU rpm
the fuel cutting and restoration timing pattern for downshifts will be different to the pattern for upshifts

the K response is about as quick as the ICE's
if the K was not energised the shifts would be slower as its inertia would be parasitic

That all seems very reasonable.

However, I was suggesting that in that 20 milliseconds for an upshift to achieve constant lambda the boost needs to rise substantially. I don’t think it can because there isn’t enough power to drive the boost making assembly. So I think lambda is likely to be variable.

As supporting evidence for the inertia of the MGU-H and TC we know that Honda have used it to transfer energy from MGU-K to the ES via that assembly.

In my opinion the use of the MGU-H as anti-lag has been oversold. Or at least overinterpreted by many. The assumption seems to be that at any point the MGU-H can simply whizz the boost up to any value required at the drop of a hat.

Lest you take offence, I don’t include you in the many.

[henry]

Hmm clearly these cars have blow off valves, I wonder if the boost is sent to the atmosphere or re-introduced into the air box.

they can’t vent to atmosphere, it’s against the law. The Honda has a clearly visible duct from a valve on the plenum back into the inlet tract.

[henry]

850hp from the ICE?

I assume that’s supercharged not turbocharged. In which case is it really ICE given that the energy to boost the charge is externally sourced? Ditto, especially, bsfc.

I think Mercedes is close to those numbers in self sustaining mode ie no ES draw.

I see. You’re talking PU rather than ICE. Assuming 80 of that is from the exhaust, that gives around 930 hp in self sustain plus(ES) which is what they, and Ferrari claim.

[henry]

There's a rising fuel rate until 10,500 rpm, I don't think they run the same boost at all RPM's nor do I believe they run constant fuel rate, nor do I think MGU-H works all that much in motor mode. The MGU-H only works to kick start the turbo, ideal boost for a given engine speed could be achieved with as little as 30kW from the MGU-H, the exhaust energy does the bulk of the work. At peak engine torque there's easily 120kw for the turbine in the form of exhaust energy. Turbos are positive feedback devices, the more energy you put in the turbine, the more boost you make which gives you even more turbine energy.

Hmm clearly these cars have blow off valves, I wonder if the boost is sent to the atmosphere or re-introduced into the air box.

The turbine isn't able to extract 120kW from the exhaust, if it were there would be little need to made energy around a lap and they PU would never de-rate.

The turbine has to extract enough to drive the compressor as well as providing power to the MGU-H. At 120kW they would definitely de-rate. I suspect it is rather more, maybe 150, 90 to the compressor and 60 to the MGU-H

[godlameroso]

There's a rising fuel rate until 10,500 rpm, I don't think they run the same boost at all RPM's nor do I believe they run constant fuel rate, nor do I think MGU-H works all that much in motor mode. The MGU-H only works to kick start the turbo, ideal boost for a given engine speed could be achieved with as little as 30kW from the MGU-H, the exhaust energy does the bulk of the work. At peak engine torque there's easily 120kw for the turbine in the form of exhaust energy. Turbos are positive feedback devices, the more energy you put in the turbine, the more boost you make which gives you even more turbine energy.

Hmm clearly these cars have blow off valves, I wonder if the boost is sent to the atmosphere or re-introduced into the air box.

The turbine isn't able to extract 120kW from the exhaust, if it were there would be little need to made energy around a lap and they PU would never de-rate.

Big difference between 120kw for the turbine to power the compressor and 120kw on top of that for harvesting. I'm not suggesting that at all.

[OO7]

The turbine has to extract enough to drive the compressor as well as providing power to the MGU-H. At 120kW they would definitely de-rate. I suspect it is rather more, maybe 150, 90 to the compressor and 60 to the MGU-H

Big difference between 120kw for the turbine to power the compressor and 120kw on top of that for harvesting. I'm not suggesting that at all.

Thanks. I was only thinking of the energy harvested minus that used to power the compressor.

[godlameroso]

Hmm clearly these cars have blow off valves, I wonder if the boost is sent to the atmosphere or re-introduced into the air box.

they can’t vent to atmosphere, it’s against the law. The Honda has a clearly visible duct from a valve on the plenum back into the inlet tract.

I understand breather gases but I don't see where in the regulations it says 'no venting compressor air to atmosphere.'

[henry]

Hmm clearly these cars have blow off valves, I wonder if the boost is sent to the atmosphere or re-introduced into the air box.

they can’t vent to atmosphere, it’s against the law. The Honda has a clearly visible duct from a valve on the plenum back into the inlet tract.

I understand breather gases but I don't see where in the regulations it says 'no venting compressor air to atmosphere.'

5.8.1 With the exception of incidental leakage through joints (either into or out of the system), all (and only) the fluids entering the compressor inlet and the fuel injectors must exit from the engine exhaust system.

[Tommy Cookers]

[quote=henry]
However, I was suggesting that in that 20 milliseconds for an upshift to achieve constant lambda the boost needs to rise substantially. I don’t think it can because there isn’t enough power to drive the boost making assembly. So I think lambda is likely to be variable.
As supporting evidence for the inertia of the MGU-H and TC we know that Honda have used it to transfer energy from MGU-K to the ES via that assembly.[/quote]

upshifting gives a rev drop of c.16%
so fuel charge/cycle will rise 16% and air charge/cycle must rise 16% to maintain lambda
so the new absolute 'boost' pressure should be 16% higher
this is roughly equivalent to a required H rpm increase of c. 8%

fwiw my guess (from a bit of experience)
the electromechanical time constant of the H is regardable as 20 msec bare and 40 msec incl inertias eg turbine and compressor
ie it can accelerate (in vacuum) in 40 mSec to 63% of any step change in demanded rpm

so 8% change in rpm in 20 mSec seems not implausible even with the high and strongly rpm-related compressor loads


it now seems to me that with DI the ICE torque turndown and turnup can be a few msec ('1 rev')
iirc the time window when 2 gears load path components are in position simultaneously is 4 msec ('1 rev')
the time constant of ICE/K rpm is maybe 30 msec ie16% rpm turndown in 10 msec seems possible

[johnny comelately]

I'll tune my motor, you blokes do your own

[henry]

upshifting gives a rev drop of c.16%
so fuel charge/cycle will rise 16% and air charge/cycle must rise 16% to maintain lambda
so the new absolute 'boost' pressure should be 16% higher
this is roughly equivalent to a required H rpm increase of c. 8%

fwiw my guess (from a bit of experience)
the electromagnetic time constant of the H is regardable as 20 msec bare and 40 msec incl inertias eg turbine and compressor
ie it can accelerate (in vacuum) in 40 mSec to 63% of any step change in demanded rpm

so 8% change in rpm in 20 mSec seems not implausible even with the high and strongly rpm-related compressor loads


it now seems to me that with DI the ICE torque turndown and turnup can be a few msec ('1 rev')
iirc the time window when 2 gears load path components are in position simultaneously is 4 msec ('1 rev')
the time constant of ICE/K rpm is maybe 30 msec ie16% rpm turndown in 10 msec seems possible

In the end you were bound to be right.

I checked my calcs, and found that the inertia value I used was out of line. When I substitute a more reasonable value I find that I can agree with your numbers.

If my numbers are now right they suggest that the MGU-H has to be driven well outside its continuous duty output during these short bursts of activity, maybe 4 or 5 times. Does that seem reasonable?

FWIW I got the inertia from a Rotrex supercharger which can operate at similar duty, but failed to spot the gearing, which of course makes a big difference.

I was also, consequently, wrong about the Honda K->H->ES implications. Rather than a few hundred revs fluctuation its more likely it is a few thousand. If that’s right I wonder how they manage the significant variation in compressor output.

[Tommy Cookers]

re the H duty cycle

wouldn't liquid cooling mean that continuous duty can be close to intermittent duty ?
and presumably the drive is also well cooled
machine drives and K and H machines are pretty efficient maybe 97%

running a qually lap on electric supercharge is rather heavy duty and rather continuous


still thinking about the other aspect
initially I said the rpm would be low

[gruntguru]

fwiw my guess (from a bit of experience)
the electromagnetic time constant of the H is regardable as 20 msec bare and 40 msec incl inertias eg turbine and compressor ie it can accelerate (in vacuum) in 40 mSec to 63% of any step change in demanded rpm so 8% change in rpm in 20 mSec seems not implausible even with the high and strongly rpm-related compressor loads

it now seems to me that with DI the ICE torque turndown and turnup can be a few msec ('1 rev')
iirc the time window when 2 gears load path components are in position simultaneously is 4 msec ('1 rev')
the time constant of ICE/K rpm is maybe 30 msec ie16% rpm turndown in 10 msec seems possible

Some great info in that post Tommy.
What is the power required to accelerate the H from say 120k rpm to 130k (120k + 8%) in 20 mSec?

Definitely plausible - if needed they could change the setpoint for the H before the gearshift even started.