How do the current power units meter air flow into the engine?

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
roon
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Re: How do the current power units meter air flow into the engine?

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godlameroso- Is the torque fill effect overstated? The K is only ~15% of PU output.

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Re: How do the current power units meter air flow into the engine?

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Of max output, but what about 7,000rpm? Where 200nm could be half total torque output, not to mention the K not only boosts crank torque but can also reduce it. So it's really + or - 200nm.
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Cold Fussion
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Re: How do the current power units meter air flow into the engine?

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It's probably likely that any time they are going slow enough to be at 7000 rpm, they would also be traction limited.

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Re: How do the current power units meter air flow into the engine?

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OT, but .....that's just where the 'not traction control' characteristics of MGU-K action are most valuable to laptime

the inherent internal characteristics of the MGU-K drive very usefully vary the MGU-K action in a wheel slip situation
as well as externally ie transparently varying its action ie resembling an upshift 'snapping' from full M to full G

the ICE response in a slip situation presumably also benefits via internal and external routes including modulation of MG-H/turbo rpm

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PlatinumZealot
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Re: How do the current power units meter air flow into the engine?

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godlameroso wrote:
Wed Mar 29, 2017 3:36 pm
Do they use MAP sensors MAF sensors or a combination of both, or neither?

I suppose they'd have to use both to some extent, because MAP sensors are more geared towards predetermined maps, but at the same time you lose some precision in comparison to a MAF sensor. The drawback of the MAF sensor of course being sensitive to pressure waves in the intake depending on flow, pipe length, frequency.
Cheap MAF sensors experience those problems.. The MAF or thermal mass sensors that we use in industry are highly accurate in many conditions. i suppose F1 engines would use MAF sensors of similar quality. Your typical automotive MAF is designed to be affordable and just accurate enough to work. Industrial sensors have to work in wider ranges of temperatures and flows and electrical noise and mkae use advanced techniques to minimize pressure effects. Really and truly a thermal mass sensor should be located far away from the wake of active valves. If not you can program them to respond differently to various valve positions (wake)
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They also use pressure sensors to know the boost of course.

Turbine speed is also measured.

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Re: How do the current power units meter air flow into the engine?

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gruntguru wrote:
Fri Mar 31, 2017 4:24 am
Probably a more interesting question is "what role does air flow play in regulating the output of these engines?"

Traditional approach.
Driver's foot demands a change in torque output. Butterfly valve(s) adjsut to change airflow to engine. ECU senses any change in airflow and/or MAP and/or Throttle position and adjusts fuel quantity to maintain best-power AFR.

New approach.
Driver's foot demands a change in torque output. ECU immediately adjust fuel quantity to match the torque demanded. (This is possible under most conditions because the engine is running in a highly-excess-air state and more fuel will produce more power - instantly). At the same time the ECU will adjust butterfly valves and/or MGUH output to bring the MAP and exhaust-backpressure (and therefore air flow) to the most efficient levels for the new fuel rate.

So airflow plays a slightly less critical role in the current lean-burn ICE.

BTW. Sensing exhaust-backpressure would also be essential.
I would expect the control strategy to be similar to what is normally used with diesel engines these days. Pedal position is translated to a torque request using pedal maps and engine speed and from this torque request the fuel mass that needs to be injected can be calculated. Fuel limits based on how much air the engine currently consume prevent the engine from going too rich. Airmass can be calculated using either speed-density or alpha-n with density correction, and given that F1 engines favour individual throttles I would expect alpha-n to be used; that is throttle position and engine speed as the main inputs to the airmass flow calculation model and using the density of the air in the plenum as the main correction. An airmass meter isn't required, and not really desirable either as they have a sluggish response during transients, restricts the airflow to the engine and can be fooled by pressure pulsations (caused by for instance compressor surge).

Once the injected fuel mass have been calculated, it is possible to calculate how much air the engine need to burn that fuel optimally, which is then achived by adjusting throttle position and boost pressure until m_air_actual = m_air_req. This is basically how any modern diesel engine works except for the use of airmass meters as the main input for airmass flow (usually using speed density as backup in case of MAF malfunction or during transients to improve response).