Dual Spark Plugs

[autogyro]

Hmm, valve repair as usual?
They get way to hot.

[mach11]

hello everyone...

during the bahrain grand prix vettel reported loss op power during lap 33 which was initially suspected to be exhaust faliure... but later on was reported to be a spark plug faliure....

my question is

when so much of research and testing is being done on the engine how can a spark plug fail????

and

what exactly happened in his car... cause if a spark plug fails then ( in my assumption ) that cylinder will not fire which will lead to hugh amounts of vibration and would have affected the dynamic balancing of the crankshaft....

slightly off topic but i din want to start a separate thread....

hope i was clear in my questioning

thanks in advance

[Belatti]

when so much of research and testing is being done on the engine how can a spark plug fail????

There are still imperfect human beings that have to manufacture things and quality control.

what exactly happened in his car... cause if a spark plug fails then ( in my assumption ) that cylinder will not fire which will lead to hugh amounts of vibration and would have affected the dynamic balancing of the crankshaft....

There are different failure mode scenarios:
1) intermitent fail cause a wire connector bad contact
2) spark not producing at certain frequencies (rpm)
3) the spark simply got dirty
4) an electrode broke
etc...

[mcjamweasel]

Twin spark heads are fairly common in motorbikes, notably Triumph use them in the 2300cc triple Rocket III and the 1600cc twin cyl Thunderbird and BMW use them in their 1200cc twins. These bikes all have 4 valve heads. Primarily it's used for a cleaner, more complete burn.

[marcush.]

the speed of the flamefront is something of a constant so inevitably ,revs and bore diameter put limits into this game..
with big bore diameters over 100mm you surely are closing in on getting in trouble with flame propagation even with centred sparkplugs I have heard.

[alelanza]

when so much of research and testing is being done on the engine how can a spark plug fail????

There are still imperfect human beings that have to manufacture things and quality control.

what exactly happened in his car... cause if a spark plug fails then ( in my assumption ) that cylinder will not fire which will lead to hugh amounts of vibration and would have affected the dynamic balancing of the crankshaft....

There are different failure mode scenarios:
1) intermitent fail cause a wire connector bad contact
2) spark not producing at certain frequencies (rpm)
3) the spark simply got dirty
4) an electrode broke
etc...

Interesting topic. The one thing that's been bugging me is what made the spark plug 'fix itself', or was it just Vettel freaking out and/or taking care of the engine until he knew the problem wasn't that big?

[DaveKillens]

what exactly happened in his car... cause if a spark plug fails then ( in my assumption ) that cylinder will not fire which will lead to hugh amounts of vibration and would have affected the dynamic balancing of the crankshaft....

Yes, if a spark plug failed there would no longer be any fire and bang in that cylinder. But the mechanical parts are still in place, and thus, the balancing of the crankshaft would be unchanged.

There would be a loss of power, and the crankshaft would be subject to less torque than before.

How many times in the past have Formula One cars retired because of spark plug failure? Bottom line, this is a very rare occurance with what is usually a very reliable part. I guess all any team could do is step up the quality control, and conduct stringent non-destructive tests on all spark plugs. For instance, X-ray them to make sure the internal structure is as designed.

[riff_raff]

A 4 valve head like in F1 would not benefit from an additional plug. Besides, there's no room to put a second plug where it would do any good.

F1 plugs are incredibly small in diameter (maybe between 8mm and 10mm at the threads?) with a very long reach. These conditions are not good for a durable spark plug. But somehow companies like NGK, Denso, Bosch, Champion, etc. get them to work.



Red Bull apparently doesn't have a spark plug sponsorship. Because the cardinal rule in professional racing is never blame a DNF on a sponsor-related component.

[Belatti]

Interesting topic. The one thing that's been bugging me is what made the spark plug 'fix itself', or was it just Vettel freaking out and/or taking care of the engine until he knew the problem wasn't that big?

Remember at the end he had less fuel...

Extrapolate his times till lap 32 in your graph and probably he should have been lapping a couple seconds less at the end of the race

[autogyro]

Interesting topic. The one thing that's been bugging me is what made the spark plug 'fix itself', or was it just Vettel freaking out and/or taking care of the engine until he knew the problem wasn't that big?

Remember at the end he had less fuel...

Extrapolate his times till lap 32 in your graph and probably he should have been lapping a couple seconds less at the end of the race

I make it closer to two and a half seconds less.
Spark plugs rarely fail completely and setting mixtures and ignition would account for the initial large lap time drop followed by a return to the fuel load reducing curve over 2 seconds under Webers times. Previously he was nearly 2 up on Webber so it was a big drop.

[alexbarwell]

Granted failure is few and far between, but very high voltages and temperatures is a tough act. A plug can fail in the electrode - not able to connect the drive to the electrode tip sufficiently causing a weak spark and a small (and slow to propagate) flame front, but also if high voltage tracking happens externally (like a hairline crack or contamination)some, or all of the spark energy can be discharged externally to the chamber, which is no help, but vibration could make any of this come and go. Maybe if there were room (new materials?) rather than the spark-carrier being the centre electrode, if it could be carried in a concentric collar with the spark developing to both an outer and an inner contact - multiple spark points in 1 plug. Not sure if this is a legit way to bend the single plug rule.

[Shrek]

since there is now a regulated weight for the engine, why make them small anymore, just make them so they last

[mcjamweasel]

They need to be kept small to allow more valve area. Also, are they weighed as part of the engine? Or are they counted as part of the electrical system?

[alelanza]

Interesting topic. The one thing that's been bugging me is what made the spark plug 'fix itself', or was it just Vettel freaking out and/or taking care of the engine until he knew the problem wasn't that big?

Remember at the end he had less fuel...

Extrapolate his times till lap 32 in your graph and probably he should have been lapping a couple seconds less at the end of the race

But he also had 'less' tyres, can't directly extrapolate. Look at other drivers times, none show the sharp downward curve that Vettel's post failure lap times show. Of course, we can say they were not motivated to push, but take the two merc drivers, i recall schumi being told that if he pushed he might be able to catch Vettel towards the last laps. Rosberg was chasing him as well. Despite this, look at their lap time curves:


vs


Only the force indias come close, but they were on different rubber. The ferraris, Hamilton and the mercs were also on lighter fuel every lap, yet the red ones passed him by very easily, Hamilton seemed to make a slightly bigger effort, and Rosberg had no chance.

I also find it surprising none of the telemetry showed them what the problem was. Even more bizarre after hearing LH say it wasn't firing on all 8 and then hearing Horner say they thought it was an exhaust.

If it wasn't the driver freaking out, then somehow that engine healed itself without the telemetry showing much to the team. Conspiracy theorists would surely be happy to come up with a reason why the team preferred to initially blame the exhaust and then switch to blaming the plugs.

[autogyro]

I cannot see any sign in the graphs for the plug problem curing itself.
I think Webber slowed towards the end. probably as insurance for the team not having a similar car problem.
From my own experience, if you can get a sick car to cruise at a good high speed, it is better to keep it there rather than slow down and risk a complete cut out.