Capacity of F1 fuel injectors.

[godlameroso]

Max fuel flow is 100kg/hr, which is ~133 liters per hour, or ~2216cc/min @ a max 500 bar injection pressure. Naturally we divide by 2 because there are 2 fuel rails. This gives us 1108cc/min available to each fuel rail, provided each cylinder bank is contributing equally. I'm assuming the capacity of the injectors would follow the 85% duty cycle rule, therefore I believe F1 fuel injectors are ~1,400cc/min. Being piezoelectric injectors, I'd be interested in knowing fuel rates in ms, .023 cc/ms? Is that even possible?

I wonder if the fuel pump is a similar capacity, ~150lph to maintain that 15% duty cycle headway. If so that's a tiny fuel pump, an old Toyota Supra from 1998 came from the factory with a 320lph fuel pump.

[saviour stivala]

“Capacity of fuel injectors”. From my notes as regards fuel injectors, fuel flow, fuel pump.
The 100kg/h max fuel flow at 10500RPM of the present power unit is slightly higher than what the previous NA 2.4 litre V8 was using at 17500RPM.
Renault present power unit was using 2 mechanical high pressure fuel pumps each driven by inlet camshaft.
1955 Mercedes M196 2.5-litre eight was using in-cylinder direct fuel injection by a mechanical plunger pump. The injector nozzle position was on cylinder wall bellow the inlet valve. With the nozzle being angled upwards 12.5 degrees. With fuel flow starting 30 degrees ATDC intake stroke and continued for 160 degrees.

[Tommy Cookers]

The 100kg/h max fuel flow at 10500RPM of the present power unit is slightly higher than what the previous NA 2.4 litre V8 was using at 17500RPM.

that can't be right ?
(even allowing for hybrid F1 fuel being specially high in mass-specific heating value)
(even allowing for much NA racetime being at the reduced richness/power/rpm for 'better' efficiency and durability)
if that is right isn't the whole hybrid F1 thing a big lie ?

Mercedes said about a million times that ......
NA F1 was 29% efficient so their '50% efficient' hybrid F1 fuel consumption was far smaller than NA F1's
everyone had values of NA fuel consumption far above hybrid's
as NA fuel use at 130 kg or more would imply - Merc once suggested 170 kg use presumably from full-rich fuel rate
NA F1 always ran slightly rich or richer than slightly rich


and - can godl's figures for injector rates be correct for DI ?

[godlameroso]

Why not? I understand DI can't operate in continuous shower mode, so I suppose it's better to talk about grams of fuel per second. Or 27.7g/s, which is the same as these https://www.lingenfelter.com/product/L700046914.html.

Interesting note, these injectors are capable of 5.5ms injector pulsewidth. I would hope F1 injectors are a little more precise.

[Dr. Acula]

Why not? I understand DI can't operate in continuous shower mode, so I suppose it's better to talk about grams of fuel per second. Or 27.7g/s, which is the same as these https://www.lingenfelter.com/product/L700046914.html.

Interesting note, these injectors are capable of 5.5ms injector pulsewidth. I would hope F1 injectors are a little more precise.

You're a bit over the top with that number. 27.7g/s is the overall max. fuelflow. But that's gets devided by 6 cylinders.
So the average max fuel flow per cylinder is 4.63g/s.
At 10500rpm that would be about 0.105g/cycle per cylinder if i'm not mistaken.

[Tommy Cookers]

what I was trying to say to godl ...

the maximum permitted fuel rate per cylinder is equivalent to fuelling the cylinder throughout 720 deg at 4.63 gm/sec
but fuelling over 160 deg eg as per M196 means fuelling the cylinder at 20.84 gm/sec
and at higher rates than this if the fuelling is over less than this 160 deg (which seems likely)

and regarding the Supra fuel pump effect ....
F1 doesn't recirculate fuel to the tank and the Supra does ?

[godlameroso]

Why not? I understand DI can't operate in continuous shower mode, so I suppose it's better to talk about grams of fuel per second. Or 27.7g/s, which is the same as these https://www.lingenfelter.com/product/L700046914.html.

Interesting note, these injectors are capable of 5.5ms injector pulsewidth. I would hope F1 injectors are a little more precise.

You're a bit over the top with that number. 27.7g/s is the overall max. fuelflow. But that's gets devided by 6 cylinders.
So the average max fuel flow per cylinder is 4.63g/s.
At 10500rpm that would be about 0.105g/cycle per cylinder if i'm not mistaken.

Do 6 cylinders fire at once? If only one cylinder fires at a time, then it stands to reason that the injectors will not be injecting simultaneously but timed with piston and crank position. Which is either in 90 or 150 or 270 degree intervals depending on firing order.

[godlameroso]

what I was trying to say to godl ...

the maximum permitted fuel rate per cylinder is equivalent to fuelling the cylinder throughout 720 deg at 4.63 gm/sec
but fuelling over 160 deg eg as per M196 means fuelling the cylinder at 20.84 gm/sec
and at higher rates than this if the fuelling is over less than this 160 deg (which seems likely)

and regarding the Supra fuel pump effect ....
F1 doesn't recirculate fuel to the tank and the Supra does ?

Returnless systems manifest their limits at the fuel rail, since they lack a pressure regulator, however this is a PI not a DI system. As I'm sure you know DI systems need an accumulator/secondary pump to boost fuel pressure, which means you don't need a separate regulator and a return line to maintain adequate fuel pressure.

[Dr. Acula]

Why not? I understand DI can't operate in continuous shower mode, so I suppose it's better to talk about grams of fuel per second. Or 27.7g/s, which is the same as these https://www.lingenfelter.com/product/L700046914.html.

Interesting note, these injectors are capable of 5.5ms injector pulsewidth. I would hope F1 injectors are a little more precise.

You're a bit over the top with that number. 27.7g/s is the overall max. fuelflow. But that's gets devided by 6 cylinders.
So the average max fuel flow per cylinder is 4.63g/s.
At 10500rpm that would be about 0.105g/cycle per cylinder if i'm not mistaken.

Do 6 cylinders fire at once? If only one cylinder fires at a time, then it stands to reason that the injectors will not be injecting simultaneously but timed with piston and crank position. Which is either in 90 or 150 or 270 degree intervals depending on firing order.

Yes, but first of all in a 6 Cylinder engine some of the cycles between each individual cylinder will overlap, so there will be times where at least 2 injectors are open
Also, you have choosen to look at it at a per second basis and that's automatically an averaged out value. At 10500rpm each injector goes 43-44 times through his firing cycle in a second. You will have higher momentary flow values than the per second value does indicate, but you have also quite a bit of time in each second where there is simply no flow to an individual injector at all.

[godlameroso]

You're a bit over the top with that number. 27.7g/s is the overall max. fuelflow. But that's gets devided by 6 cylinders.
So the average max fuel flow per cylinder is 4.63g/s.
At 10500rpm that would be about 0.105g/cycle per cylinder if i'm not mistaken.

Do 6 cylinders fire at once? If only one cylinder fires at a time, then it stands to reason that the injectors will not be injecting simultaneously but timed with piston and crank position. Which is either in 90 or 150 or 270 degree intervals depending on firing order.

Yes, but first of all in a 6 Cylinder engine some of the cycles between each individual cylinder will overlap, so there will be times where at least 2 injectors are open
Also, you have choosen to look at it at a per second basis and that's automatically an averaged out value. At 10500rpm each injector goes 43-44 times through his firing cycle in a second. You will have higher momentary flow values than the per second value does indicate, but you have also quite a bit of time in each second where there is simply no flow to an individual injector at all.

Good point. If two injectors are spraying simultaneously it would be on opposite banks?

[saviour stivala]

My notes says that the F1 1.6l turbo engine maximum fuel flow rate of 100kg/h is slightly higher (by around 0.67%) than what the 2013 F1 NA 2.4L V8 maximum fuel flow rate was.
Also some more points from my notes of the ‘official data’ of the 1955 Mercedes-Benz M196 2.5-litre eight that might give a clearer picture as regards its in-cylinder direct injection system used and data.
“a 2-valve combustion chamber machined as a perfect hemisphere with 50mm inlet valve with a lift of 13mm opening 20 degrees BTDC and closing 56 degrees ABDC + A 43mm exhaust valve with a lift of 12mm opening 50 degrees BBDC and closing 14 degrees ATDC, with each cylinder fired by 2-14mm spark plugs, fuel injector positioned on the cylinder wall just below the inlet valve, with the centerline of the nozzle angled upwards at 12.5 degrees, fuel flow began 30 degrees ATDC on the intake stroke and continued for 160 degrees.” This fuel injection system used a mechanical in-line 8 plunger fuel injection pump with its own camshaft with the cam-lobes shape controlling both start of injection timing and the injection duration.

[gruntguru]

Something wrong with your notes SS.

750 hp @ 30% thermal efficiency = 150 kg/hr

[gruntguru]

I'm assuming the capacity of the injectors would follow the 85% duty cycle rule, therefore I believe F1 fuel injectors are ~1,400cc/min. Being piezoelectric injectors, I'd be interested in knowing fuel rates in ms, .023 cc/ms? Is that even possible?

I doubt if the injector duty cycle exceeds 25%. They only have intake and compression stroke to get the fuel in (direct injection remember) - that's 50%, but you can't inject late in the compression stroke or early in the intake stroke and they need to vary injection timing and possibly multiple-pulse the injectors to control the prechamber vs main chamber fuelling - so considerably less than 50%.

[godlameroso]

Something wrong with your notes SS.

750 hp @ 30% thermal efficiency = 150 kg/hr

Perhaps it's as you say, and the difference comes from duty cycle. Meaning ultimately the current PU fuel injectors could flow slightly more than the V8 fuel injectors, however the duty cycle on the V8 injectors was much higher leading to more fuel used overall. As SS stated the V8 injectors would essentially spray through the entire engine cycle.

[saviour stivala]

The NA 2.4L V8 of 2013 was reputed to have been producing 750BHP at a max power speed of 17500RPM at an inlet pressure of 1Atm, at that speed it was using ‘shower’ injectors showering fuel for virtually 720 degrees of its crankshaft angular rotations with no restrictions on fuel flow. It was consuming between 140 and 150kg of fuel over a race distance by being able to run at maximum power for a longer period of time/distance during a lap.
The present forced induction 1.6l V6 is reputed to be producing 840BHP at a max power speed of 10500RPM at an inlet pressure of between 3 and 4Atm, it is using in-cylinder direct injection with the injectors not possible to injecting for more than 180 degrees of crankshaft angular rotation at the most, with a fuel flow restriction of max 100kg/h. it is consuming 100kg of fuel (again restricted) over a race distance by being able to not run at maximum power for a shorter period/distance during a lap.
The in-cylinder direct injection injectors being used have at minimum double the fuel flow rate capacity of the shower type injectors used on the NA 2.4L V8. And the max fuel flow rate of the present forced induction 1.6l V6 is around 0.67 percent more than what the NA 2.4L V8 was using.