F1technical.net

Hey all. Over the last few races I believe Fred and Bulk haven't been able to really put the engine to 18,000 rpm due to heating/reliability issues, I believe? What exactly are the issues with them revving full? Is it temp? Is it fuel (I mean as in like the situation with the VR-01). Also I heard Rob Smedley talking to Felipe Baby several times to use the "overtake" button. Are they using the engine's limited revs as a "KERS," almost? To take it to full 18,000 on the straights, or just to overtake? Thanks.

I'm not sure about the reason for their reliability problems. The team will not run at 18,000RPM for the full race distance to help their engine last the race distances that it will need to cover and if they want to save fuel. They will do this especially if they are way out infront or have no chance in improving their race position. There is no point in stressing the engine if no gain will be had.

I think that the "overtake" button makes the rev limit bang on 18,000RPM and changes the fuel mixture for more power (I'd guess that it makes it more rich)

Callum wrote:I think that the "overtake" button makes the rev limit bang on 18,000RPM and changes the fuel mixture for more power (I'd guess that it makes it more rich)

Exactly my point of view. As you said, the 'magic button' probably increases the rev limit and changes the fuel mix. I can recall FI using it during the last season's Belgium GP.

It doesn't change the fact, that the Ferrari engine is quite a hothead. They've problably cut too many corners as far as cooling's concerned, and now it has backfired on them. As they're standing on the verge of overheating, any unpredicted situation may result in an engine failure (e.g Fred's DNF during the last GP). Alonso's engine cooling was already distorted by the car in front of him, and pressing the magic button in such circumstances must have resulted in a smokescreen.

Although Alonso's engine expired in a dramatic fashion just two laps from the end, the circumstances surrounding this event have to be taken into consideration. It was a very hot and long race. Alonso had gearshift problems, which probably made life harder for the engine (nothing can bring an engine to max revs than a missed shift into neutral). Alonso had been racing a lot of cars hard, and he had pushed his car hard almost the entire race. So when he attempted to pass Button, it was at the end of the longest straight, and against the car with the highest terminal speed. Also, Alonso attempted this move two laps earlier, without success, thus further straining the engine.

So when Alonso did manage to come alongside Button on that dramatic lap, his engine was forced into maximum revs, probably a little more because he was in Button's draft. My opinion is his engine exceeded the engineer's design limits.

The failure itself wasn't the bottom end, it started on the right bank. Most likely something in the valvetrain.

Well, on the bright side (for tifosi) they have a real reason to make changes for reliability!

How can the engine go over max revs? Isn't it electronically controlled?

http://www.grandprix.com/ns/ns22179.html

It appears that at the core of Ferrari's problems they had over heating. They may have then taken some revs away in their engine maps in several gears which they allowed the drivers to recover by a "Boost button" for critical race situations.

Alonso's Malaysia problem almost certainly is related to the clutch problem he had by loosing the clutch activation connector. As I already suspected on race day the botched overtaking maneuver on Button may have been the straw that broke the camel's neck. If Alonso misses two points in the end he will rue that maneuver.

The overtake button justs sets the engine to maximum power setting for the time the button is pressed down.

hollus wrote:How can the engine go over max revs? Isn't it electronically controlled?

Yes, the ECU is programmed never to exceed 18,000 RPM. But the shut-down process is not immediate or sudden, most likely it starts to shut down fuel injectors. But in a tow, I believe that when the engine hits 18K, if just one cylinder bank is shut down, the engine may provide enough power to stay in the draft, and go just a little bit faster.

If F1 engine designers were really clever, they would design a drive system for the engine auxiliaries that could be disconnected for a few seconds to provide a few extra horsepower at the wheels during passing. The oil system could have a small accumulator to provide oil pressure during this brief period. And the engine could run without a coolant pump or alternator for a few seconds.

Here's what the rules say: "With the exception of electrical fuel pumps engine auxiliaries must be mechanically driven directly from the engine with a fixed speed ratio to the crankshaft"

But one might interpret that it doesn't preclude simply disconnecting the fixed ratio auxiliary drive to the crankshaft, since at that point they are not specifically being driven and technically would not be performing an auxiliary function.

Maybe I should have been a lawyer? :^o

riff_raff wrote:If F1 engine designers were really clever, they would design a drive system for the engine auxiliaries that could be disconnected for a few seconds to provide a few extra horsepower at the wheels during passing. The oil system could have a small accumulator to provide oil pressure during this brief period. And the engine could run without a coolant pump or alternator for a few seconds.

Here's what the rules say: "With the exception of electrical fuel pumps engine auxiliaries must be mechanically driven directly from the engine with a fixed speed ratio to the crankshaft"

But one might interpret that it doesn't preclude simply disconnecting the fixed ratio auxiliary drive to the crankshaft, since at that point they are not specifically being driven and technically would not be performing an auxiliary function.

Maybe I should have been a lawyer? :^o

I don't know Terry, even if you could, how many Hp are we talking about here? If the oil pump circulates 10 liters per minute (2.7 gpm) against 1 MPa (145 psi) pressure, that's 170 W or 0.23 Hp and even if you double that flow and add a 50% efficiency it's still less than 1.0 Hp.

xpensive,

I would guess that the oil pump pressure, scavenge, and deaerate functions probably produce a parasitic loss of about 6 to 8 HP at the crank at max rpm. The coolant pump about the same. And the alternator loss is probably less than 1 HP.

So maybe 12 to 14 HP total for a brief period? Just my guess.

riff_raff

Terry,
With the respect for your profession, I will take your word for that, I was just trying to draft a calc.

Anyway, with 12-14 Hp, I guess you have a point, but for how long can you do without the auxillieries, 6s?

Oil flow is what, 20 Lpm, why you would need a 2 liter accumulator, doable I guess.

thomas

So my question is could the problem with the Ferrari engine be caused by the tilting of the engine at 3 degrees to get the bigger diffuser under the car? I am thinking they are getting a oil starvation problem in the rear of the engine, thus causing more heat and failure. Am I even in the ball park here?

GrndLkNatv,

Tilting of the engine would not cause an oil starvation issue. F1 engines are dry sump.

xpensive,

My F1 engine auxiliary drive idea was just a topic for a fun discussion. You're correct, an additional 12 to 14 HP for a few seconds would not be worth the risk.
Thanks for playing along!

riff_raff