2025/2026 Hybrid Powerunit speculation

[vorticism]

How about: traverse the entire crankshaft fore or aft slightly along the crank axis, causing all six of the connecting rods big ends to fall away or toward the cylinder centers. +/- Xmm to achieve center when the engine is running to get the extra travel at TDC. Design the crank throw journals and/or bearings with crown such that they are spherical. Might get away with using a typical cylindrical wrist pin and live with the piston itself being angled slightly within the bore during the test. We're only talking about half millimeters and fractions of degrees here. At rest (incl when turned slowly for test), the conrods are slightly angled, when running the conrods are straight with the big ends aligned with the cylinder centers.

I guess this could be achieved with TE; a static plastic disc pushing on a thrust bearing that contacts the crankshaft f.e. Or by oil pressure or some other means. At operating speeds would centrifugal forces be sufficient to take over and assure alignment? Or would the device always be receiving thrust/axial loads from the conrods trying to push off-axis. In which case how bad would frictional losses to thrust bearings be.

Note the previous 18:1 CR was not inspected for (afaict). This new one will be and there are only so many ways to do that. I’m assuming it is an optical or contact measurement of the piston face performed through the spark plug hole, or with the cylinder heads removed. Obviously running temperatures would not be convenient to achieve in that scenario, short of heating the engine in an oven, removing it, and performing all of the measurements within a certain amount of time as it cools down. Why is a CAD inspection not sufficient? Presumably that is what was done over preceding decade. Why does the FIA now want to measure this instead of infer it?

[Farnborough]

Of interest to the discussion, if not seen before.



More in depth overview of the last generation PU.

[diffuser]

Of interest to the discussion, if not seen before.



More in depth overview of the last generation PU.

Interesting. Most interesting is they have in cylinder pressure sensors.....

[BassVirolla]

How about: traverse the entire crankshaft fore or aft slightly along the crank axis, causing all six of the connecting rods big ends to fall away or toward the cylinder centers. +/- Xmm to achieve center when the engine is running to get the extra travel at TDC. Design the crank throw journals and/or bearings with crown such that they are spherical. Might get away with using a typical cylindrical wrist pin and live with the piston itself being angled slightly within the bore during the test. We're only talking about half millimeters and fractions of degrees here. At rest (incl when turned slowly for test), the conrods are slightly angled, when running the conrods are straight with the big ends aligned with the cylinder centers.

I guess this could be achieved with TE; a static plastic disc pushing on a thrust bearing that contacts the crankshaft f.e. Or by oil pressure or some other means. At operating speeds would centrifugal forces be sufficient to take over and assure alignment? Or would the device always be receiving thrust/axial loads from the conrods trying to push off-axis. In which case how bad would frictional losses to thrust bearings be.

Note the previous 18:1 CR was not inspected for (afaict). This new one will be and there are only so many ways to do that. I’m assuming it is an optical or contact measurement of the piston face performed through the spark plug hole, or with the cylinder heads removed. Obviously running temperatures would not be convenient to achieve in that scenario, short of heating the engine in an oven, removing it, and performing all of the measurements within a certain amount of time as it cools down. Why is a CAD inspection not sufficient? Presumably that is what was done over preceding decade. Why does the FIA now want to measure this instead of infer it?

Angled pistons are a neat receipt for a fast piston and cylinder failure, it's why is important for the rods to not being twisted nor bent.

Nevertheless, I can understand why you talk about spherical throws (and piston pin!) to angle the rod, but I still cannot figure how you get the throw from offset to centered.