F1 Piston Analyzation
F1 Piston Analyzation
(OP)
http://members.atlasf1.com/desmo/pistoncrown.jpg
Any idea what the mushroom shaped "pad" in the center of the piston i for? My first guess would be for a Saab style Spark-to-Piston setup, but it seems awful wide for this purpose. Any better guesses would be appreciated.
More pics:
http://members.atlasf1.com/desmo/pistone.jpg
http://members.atlasf1.com/desmo/pistone2.jpg
Thanks! Kai
Any idea what the mushroom shaped "pad" in the center of the piston i for? My first guess would be for a Saab style Spark-to-Piston setup, but it seems awful wide for this purpose. Any better guesses would be appreciated.
More pics:
http://members.atlasf1.com/desmo/pistone.jpg
http://members.atlasf1.com/desmo/pistone2.jpg
Thanks! Kai





RE: F1 Piston Analyzation
RE: F1 Piston Analyzation
First, I agree that this is most likely not a spark-to-piston setup. As the contact pad is far too low and wide. Also I do not believe a spark-to-piston ignition system could provide the spark advance required to generate 18,000+ RPM operation.
As a guess, I'd say it's for either piston face cooling or structural reasons. It could be used for better flame kernel propagation during combustion, but I can't say for sure without looking at the CC. Be interesting to hear something from a Ferrari aficionado.
The only semi-recent* F1 engines I've seen the inside of were the Benetton 'Playlife' FB02 (long block and internals, no manifold or induction) and the Mugen-Honda MF 301HE (complete engine minus electronics). I do believe these engines were run during the same time frame as the Ferrari 049. Which would be around the 1999-2000 era. Though these engines ran pistons of similar overall proportions to the Ferrari pics you provided, each was doing it's own thing when it came to piston faces.
BTW – if you have any more pics of F1 internals, I'd absolutely LOVE to seem them.
*In Formula 1, the word 'recent' means you saw it at the Friday practice session before the race. Otherwise it's old news.
Regards,
Bryan Carter
RE: F1 Piston Analyzation
I thought I’d share my thoughts-substantiated educated speculation.
Looking at the Ferrari piston shown I'd simply say that the engine is over square-savagely so by modern production road car standards. Now anyone who has tried to develop an oversquare engine and tried to get the compression ratio high, will sympathise with how difficult this can be while trying to use as flat a piston as possible.
Shallow combustion chamber valve angles help, but due to the constraints this puts upon valve area and/or port flow/bore shrouding this isn't always ideal.
I would say that on a formula 1 engine the priority for good breathing is an extremely high priority-so valve area and good port low are of the utmost priority.
So to put this all into perspective, we’re left with a very oversquare engine with quite a deep combustion chamber valve angle (substantiated educated speculation).
Add to that the need for this engine to rev to phenomenal speeds-making valve timing criticial.
This would mean a late IVC point and decent overlap (goes hand in hand with the tuned exhaust for good scavenging). So now we’re left with big valves with quite a large included angle, open for a big duration-especially when the piston is a TDC.
Hence the need for HUGE piston cut outs-to avoid piston to valve cut outs. Which means the only option to get the compression ratio is up is to make protrusions as shown in the piston crown.
RE: F1 Piston Analyzation
Hence the need for HUGE piston cut outs-to avoid piston to valve cut outs. Which means the only option to get the compression ratio is up is to make protrusions as shown in the piston crown.
I had thought along similar lines, and it is a very valid point. The thing that troubles me is that other F1 pistons I have seen appeared to be relatively flat, save for the valve cutouts, there were no surface protrusions.
From looking at the piston crown we can get an idea of the depth of the chamber and make estimates about the included angle, but other than that I won't speculate further. It's sort of like looking at the quench pad of a specific piston; it doesn't make a lot of sense until you see the combustion chamber that it's mated to.
All-in-all, I'd probably say Marquis is correct.
Regards,
Bryan Carter
RE: F1 Piston Analyzation
Ryan
RE: F1 Piston Analyzation
John Woodward
RE: F1 Piston Analyzation
I believe I said that
RE: F1 Piston Analyzation
I think besides all the issues went so far, it could also help to have more turbulant charge. If you think how the charge(air fuel mixture, or just fuel in DI tech) faces the piston and reflects back, you will get this idea that this piston shape gives the charge more turbulance which help better fuel ionization and it finally leads to more efficient combustion.
Cheers
You can live in your car, but you can't drive your House!
RE: F1 Piston Analyzation
RE: F1 Piston Analyzation
RE: F1 Piston Analyzation
If you look at the piston it's pretty clear from the burn pattern that the combustion is happening in the two valve relief "troughs" on either side of the flat area in the middle.
RE: F1 Piston Analyzation
RE: F1 Piston Analyzation
RE: F1 Piston Analyzation
IF you built two engines with identical combustion chambers, bores, etc, but different rotating assemblies for different strokes (crank, rods and pistons with same crowns but diff wristpin locations), at which intersection (same mean speed, or same mean acceleration), would thier flame speeds be approximately the same?
I know it's complex problem, so make the appropriate assumptions...