NL_Fer wrote:Could it be a miller/adkinson cycle?
Variable valve timing is not allowed, but the engines have a limited powerband, so closing the intake valves on a fixed delay of a few degree after BDC could work i guess. Practicly lowering the compression ration, but keeping a larger, more efficient expension ratio.
The hybrid turbocharger would replace Millers supercharger and the MGU-K can also assist for lost power at low rpm,......
are/aren't they already using such ?? (to some extent)
I have assumed in the past that the rules intentionally preclude all more-expansion-in-cylinder type cycles
but they don't (only the crankshaft-related ones)
it sounds good, but ......
there could be problems realising a very small combustion chamber volume without inhibiting valve motion/size wrt piston clearance etc
in every engine design the charge is in principle (relative to the CR/ER) is in some way limited
eg as shown by the few supercompression N/A aircraft engines c.1917-1935 and the legions with manual boost control
where operator throttling was necessary at low altitudes even for full power
but (here) surely any limiting of the charge is done better by designing to lessen boost, rather than limiting the inlet valve opening duration ?
as this would tend to increase recovery