Pre-Season Engine drama

[Nitrodaze]

I suspect that *IF* we ever find out that the rumors are true, the metals that expand will be used in very limited areas. As you say, all metals expand with temperature, but for the most important areas this has been factored in so that the engine is at it's best under full operating temperature. As such bores, pistons, rods, valves, bearings would likely not change over how they were designed. Otherwise it would probably result in either increased engine wear or excess friction.

BUT we have areas which could expand slightly with heat and not impact wear or friction in a negative way.

*IF* they do dig in enough to find out if the rumors are true, I'm primarily suspecting various coated surfaces within the actual combustion chamber area and/or the TJI/HCCI prechamber areas, primarily the nozzles. Piston crowns, valve faces, and the various prechamber components could expand without impacting tolerances beyond what is desired to raise compression ratio.

*IF* the rumors have merit, it would take expansion that would decrease the chamber area of each cylinder by a bit less that one cubic centimeter. With a large bore as well as large valves there is a decent bit of surface area to play with, and it might be possible.




It will be interesting to see what comes out of the FIA meeting, but I have a feeling that it might end up like the Ferrari engine saga. Clarifications and changes forced, but nothing ever proven that the public gets to see.

If they have found a loophole, it would most probably be in the design of the conrod. They may have designed the conrod to stretch under temperature to increase the compression from 16:01 to 18:1. The Aluminium block and bore may be the same as from the previous engine. Of course, this is pure speculation; we would never know what trickery they may have used. Whatever it is, it is quite ingenious.

[Steve Boyd]

The swept volume limit is 1600 cc, so 266.7 cc per cylinder.

For a 16:1 compression ratio the combustion volume is therefore 17.78 cc.

For the compression to increase to 18:1 the combustion chamber needs to reduce to 15.69 cc, a reduction of just over 2 cc.

If we take the bore of the engine to be 80 mm (as indicated by the "2014-2025 engine technical specifications" on this page https://en.wikipedia.org/wiki/Formula_One_engines) then expanding the length of the conrod and piston crown height by 0.4 mm would do the trick.

Sounds simple but the crankcase and cylinder head also expand so you've got to get the rod+piston crown height to expand by 0.4 mm more than the expansion of the crankcase+head. The problem here is that aluminium alloys, typically used in crankcases expand by roughly twice as much as the steels typically used in conrods for the same temperature rise. It might actually be easier to use an alloy steel for the crankcase and reduce that expansion rather than try to increase the expansion of the rod+piston.