F-1 Oil burning to increase power

[Shannow]

Originally Posted By: OPR4H
It has some points on this. Cetane is about the moment the air fuel mix is ignited, the octane is before that, so there's no one correlaction between the two distant phases and repective events and/or facts.


Not sure on your sicence there, maybe it's translation...

Cetane is the measure of a fuel's ability to auto-ignite under heat and pressure. Octane is the measure of the fuel's resistance to autoignition under heat and pressure.

 

[OPR4H]

IMO, Cetane has more to do with speed flame and complete burning at a max. angle (time), after ignition start. Octane is avoidance of ignition. The oil added to gasoline fuel system in a spark ignition engine doesn't consider cetane, since the spark will start the flame. Anyway, it shouldn't pre-ignite the mix or the oil will arrest power instead of helping. Therefore, Cetane doesn't matter, since preigniting is totally undesirable.

 

[Shannow]

Originally Posted By: OPR4H
IMO, Cetane has more to do with speed flame and complete burning at a max. angle (time), after ignition start. Octane is avoidance of ignition. The oil added to gasoline fuel system in a spark ignition engine doesn't consider cetane, since the spark will start the flame. Anyway, it shouldn't pre-ignite the mix or the oil will arrest power instead of helping. Therefore, Cetane doesn't matter, since preigniting is totally undesirable.


Ahhh...Opinion on what the scienc is rather than understanding the science.

I see...it is what I stated, not what your opinion is.

 

[OPR4H]

IT HAS TO DO WITH COMBUSTION SPEED

https://en.m.wikipedia.org/wiki/Cetane_number

So a better cetane is the fuel that ignites almost instantaneously in a mild temperature and pressure? No. So your poor definition is way more unscientific. It has to do the way the fuel burn, how long it take to complete burn after it starts, not just the initial event. On the other side your beloved graph only shows pretty low cetane fuels, you know? They're, not in par with modern diesels that runs about 48 cetanes and above. Because it's cetanes from gasoline!?

 

[Shannow]

I'll quote Heywood, from Internal Combustion Fundimentals.

"The ignition quality of a fuel is defined by it's cetane number.Cetane number is determined by comparing the ignition delay of the fuel with primary reference fuel mixtures in a standardised test engine. For low cetane fuels with too long an ignition delay, most of the fuel is injected before ignition occurs, which results in very rapid burning rates once combustion starts, with high rates of pressure rise and high peak pressures...
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.
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For higher cetane number fuels, with shorter ignition delays, ignition occurs before most of the fuel is injected. The rates of heat release and pressure rise are then controlled primarily by the rate of injection and fuel air mixing, and smoother operation results."

It's ALL about the resistance to autoignition, and hence the DELAY between commencement of injection and combustion starting.

The wording in your wiki article is poor, in that speed is the time that it takes for combustion to commence, NOT the rate of burning.

 

[Jetronic]

That's how 2EHN works aswell, it has a very short delay to start burning, and the extra rise in temperature and pressure from the 2EHN burning speeds up the ignition of the rest of the fuel. But the rate of burning doesn't change significantly after the 2EHN has ignited.

 

[PabloZ]

I tested many engines, and if engine takes a lot of an oil, then compression can gain 10-15%.
For instance engine with good meintance will have 13 bar.
If the engine will have medium wear then compression can be 9-12 bar
but when then engine consume a lot of oil , then the engine can generate even 14-14,5 bar compression.
It can increase power.

 

[I_4]

Just read in Autosport today. New oil burning rules. Teams must supply the measurement of oil level in main tank to the FIA at all times. (whatever "all times" means) Teams must supply the mass of oil in tanks other than main tank, declared one hour before start. Active control valves between the PU and air intake are banned. Single oil specification per weekend. No qualifying oils.

 

[yvon_la]

Burning oil? Unlikely. It's probably more like this: Fuel and oil are heated (gas on header via fuel line. Since one float the other doesn't one surf on the other. You get the idea . Oil return to engine etc

 

[yvon_la]

I had not read the 100 kg of fuel limit that's 220 lbs thats 28 gallon us of gas. That is not a lot for turbo engine . Only one way to pull it off.they found a way to make gas vaporisation work (no pre ignition) oil is controlling pre ignition of gas vaporisation system. Nice idea . Those f1 guy have too much time

 

[Mitch Alsup]

A couple of points:

a) the oils that F1 cars race on is close to xxW-07 (xxW-02 qualifying). This kind of oil is thin enough to vaporize rather easily.
b) at 12K RPMs there is not a lot of time for detonation, so the low Cetane rating might not hurt as bad as it would at 2K RPMs.
c) even if the oil is burning as it runs through the turbo, there is a motor-generator at the turbo to absorb the excess energy and transmit it to the drive shaft motor,
making power even if the oil is not burning in the cylinders.

Seems to me that a oil tank size limit would solve the problem.

 

[555]

Taking into consideration that we are discussing F1 here, I'm thinking of their motor oil as slippery gasoline. You have an oil pump which can supply more pressure when needed, and pistons and a valvetrain that could allow more oil into the combustion chamber on any of four strokes under certain conditions(higher piston speed, higher oil pressure, higher temperature etc). One has to think way outside the norm of usual combustion methods.

 

[sloinker]

Originally Posted By: I_4
Just read in Autosport today. New oil burning rules. Teams must supply the measurement of oil level in main tank to the FIA at all times. (whatever "all times" means) Teams must supply the mass of oil in tanks other than main tank, declared one hour before start. Active control valves between the PU and air intake are banned. Single oil specification per weekend. No qualifying oils.


It does seem like MB has gone backwards performance wise to Ferrari this year. Maybe they can't use the oil enhancement anymore. The MB cars have been pretty smokey relative to other makes the last few years. Where there's smoke there's fire?

 

[billt460]

Originally Posted By: sloinker
It does seem like MB has gone backwards performance wise to Ferrari this year.


We have appeared to have come full circle. First it was the dominate Ferrari years, (many of them), with Schumacher. Then came the Vettel years with Red Bull. Next it was the Mercedes years with Hamilton and Rosberg. Now it appears Ferrari is back on track to take over once again.

 

[Garak]

There were some allegations Ferrari was doing the oil burning thing too at the start of the season, but nothing was ever confirmed.

 

[DeepFriar]

Originally Posted By: Garak
There were some allegations Ferrari was doing the oil burning thing too at the start of the season, but nothing was ever confirmed.


Autosport has a brief informative vid up on oil burning in this year's cars. It is at:

"F1's oil burn controversy explained" on YouTube

It's from Peter Windsor's show "The Flying Lap" also avaiable at Autosport. The show requires an app that I don't have yet but it sure does look worthwhile.

https://motorsport.tv/program/the-flying-lap/25

Cheers guys, now, back to Spa!

 

[I_4]

1.2L per 100KM down to .9L per 100KM. All I can say is that it must be bad for F1's image to have all these million dollar Power Units on track burning oil in front of millions of fans worldwide. Clever of MB to introduce their latest PU's before the reduction in consumption takes place at Monza.