F1technical.net

henry wrote: ↑

08 Aug 2020, 20:02

PlatinumZealot wrote: ↑

08 Aug 2020, 19:04

I am gonna say it seems a bad translation has happened here. I am sticking my neck out and saying this is for positive 50kW.

The equation is

Engine power(kW) = ( Q(kg/h) - 22.85) / 0.257

a flow, Q, of 10kg/hr gives -50kW As specified

So it’s not mistranslation or a typo. It really is minus50kW

Fair enough.
Still I take it as an equation for a rule. Not as a direct a physical relationship between fuel injected and net energy flow of the engine.


Unless the teams advance timing so much that the combustion is pushing against the piston as it rises up the compression stroke, the combustion should always be a net positive energy flow to the engine or else it would be wasteful.

Other losses that create subtractive energy flows. Pumping, Compression, inertia, friction etc. I think should be sufficient for engine braking?

Again i feel this rule is not to limit the propulsion or engine braking power by the fuel injected. This is to stop other tricks that can be done with fuel.

When comparing "energy in" (fuel) vs "energy out" for an ICE, you find that as "energy in" is reduced, you get to a point where "energy out" is zero (no load - ie idle or free rev) but "energy in" is still required to keep it turning. If you extrapolate downwards you find that when "energy in" reaches zero, "energy out" is negative - ie you have to drive the engine externally to keep it turning.

Maybe drivining the engine some fuel is injected for certain reasons.

I am not an ECU tuning expert... Only basic experience with megasquirt ECU... and that was a long time ago.. Didnt stay in that hobby for long ahem... But how is the fuel mapped under engine braking?
Is the goal to achieve some desireable level of acceperation/ deceleration?
Is the fuel stopped toatally?

gruntguru wrote: ↑

10 Aug 2020, 02:58

When comparing "energy in" (fuel) vs "energy out" for an ICE, you find that as "energy in" is reduced, you get to a point where "energy out" is zero (no load - ie idle or free rev) but "energy in" is still required to keep it turning. If you extrapolate downwards you find that when "energy in" reaches zero, "energy out" is negative - ie you have to drive the engine externally to keep it turning.

Very plausible, however:

That would imply that at idle, 0kW, the max fuel flow allowed is 22.85kg/hr which seems excessive, if they use less than that they’re fine. But In that case the max power under part throttle is 300kW. (100-22.85)/0.257.

And why stipulate the constant 10kg/h below -50kW?

PlatinumZealot wrote: ↑

12 Aug 2020, 23:33

But how is the fuel mapped under engine braking?
Is the goal to achieve some desireable level of acceperation/ deceleration?
Is the fuel stopped toatally?

I would say yes.
Under a fuel restricted formula it wouldn't make any sense to inject fuel when no output is required from the engine.

henry wrote: ↑

12 Aug 2020, 23:46

gruntguru wrote: ↑

10 Aug 2020, 02:58

When comparing "energy in" (fuel) vs "energy out" for an ICE, you find that as "energy in" is reduced, you get to a point where "energy out" is zero (no load - ie idle or free rev) but "energy in" is still required to keep it turning. If you extrapolate downwards you find that when "energy in" reaches zero, "energy out" is negative - ie you have to drive the engine externally to keep it turning.

Very plausible, however:

That would imply that at idle, 0kW, the max fuel flow allowed is 22.85kg/hr which seems excessive, if they use less than that they’re fine. But In that case the max power under part throttle is 300kW. (100-22.85)/0.257.

And why stipulate the constant 10kg/h below -50kW?

Agreed. I am not saying the "no load" fuel allowance bears any resemblance to reality.

gruntguru wrote: ↑

13 Aug 2020, 02:15

PlatinumZealot wrote: ↑

12 Aug 2020, 23:33

But how is the fuel mapped under engine braking?
Is the goal to achieve some desireable level of acceperation/ deceleration?
Is the fuel stopped toatally?

I would say yes.
Under a fuel restricted formula it wouldn't make any sense to inject fuel when no output is required from the engine.

Would they 'dribble' a very small amount to assist the re-gen? With the throttle closed would the air would be flowing at just the pressure from the compressor? would this be enough to 'break even'? (or am I as usual up the wrong tree)

Big Tea wrote: ↑

13 Aug 2020, 12:14

gruntguru wrote: ↑

13 Aug 2020, 02:15

PlatinumZealot wrote: ↑

12 Aug 2020, 23:33

But how is the fuel mapped under engine braking?
Is the goal to achieve some desireable level of acceperation/ deceleration?
Is the fuel stopped toatally?

I would say yes.
Under a fuel restricted formula it wouldn't make any sense to inject fuel when no output is required from the engine.

Would they 'dribble' a very small amount to assist the re-gen? With the throttle closed would the air would be flowing at just the pressure from the compressor? would this be enough to 'break even'? (or am I as usual up the wrong tree)

Max Re-gen from the K (120kW) provides sufficient braking to break traction at the rear from about 120kph down. Below that speed it might be useful to power the ICU against the K. This might be under software control, I’m not sure of the legality and anyway we wouldn’t see it. It can also be driver controlled, I have observed some drivers trailing a little throttle on the entry to corners, specifically I have observed Leclerc pick up the throttle just before entering the first chicane at Monza. Who knows why, but Monza in particular doesn’t offer much opportunity for K harvesting.

henry wrote: ↑

13 Aug 2020, 12:41

This might be under software control, I’m not sure of the legality and anyway we wouldn’t see it.

I'd say it's legal as long as the throttle pedal position is directly used to change PU output. What happens in between doesn't matter. So the teams should be able to drive the ICU against the MGU-K and -H as long as they don't exceed the 50kg/h (?) fuel limit while off-throttle which was introduced lately.

Same for the brake pedal, as long as the pedal position results in a certain torque on the rear it doesn't matter if we use the MGU-K or the brakes to slow the car down. Else you couldn't harvest energy while breaking via the MGU-K.

Both Haas’ out of FP1 due to at least one for sure ERS and the other also PU. Ferrari testing something new?

Sieper wrote: ↑

28 Aug 2020, 11:50

Both Haas’ out of FP1 due to at least one for sure ERS and the other also PU. Ferrari testing something new?

Maybe crank more then they should. Its really engineering problem. U want get thing closer to the limit to make sure u could potentially find weak spots early. Same problems Honda had when the were lacking behind. Also potentially u could gained "free" upgrade tokens trough reliability reasons. For Ferrari is no brainer. Sucks for customer teams. But sadly their performance is not got enough for really big points tally every weekend. So they could just crank everything to the eleven. Made 1 step back to make 2 forward. Except that gap is at least worth more than 1 season of development.

Steiner said one PU had a broken ICE that will definitely not be used again and on the other one it was TC releated. Both units swapped out.

Conspiracy theorist would say Ferrari are making the engines look really unreliable so they can negotiate a boatload of "reliability upgrades."

don't worry about any such things, the latest technical directive is there to prevent teams from sneaking their way to "reliability updates"

Suggested engine mode ban requires only software /steering wheel update or does it require engine update as well ?