Well, I see up to about 330 Hz max cycle rate for Festo "Fast Switching Pneumatic Valves"
and, for hydraulics:
"High-end proportional and servo valves used in applications requiring very fast response can climb into the 150 to 200 Hz range. That's up to 10 times faster than bang-bang and low-end proportional valves used in open-loop control (no feedback from the controlled parameter). Spool shift in five milliseconds IS fast!"
A 4 cycle engine running at 6000 rpm is going at 60 revs per second.
Converting all that to milliseconds:
engine at 6000 rpm: 10 ms per rev
Fast Pneumatic Valve: 3 ms per operation (specs say -10% to +30% range)
High-End---Hydraulic, etc.: 5 ms per operation
Getting all the stuff done that has to be done to get the valves open and closed accurately enough seems a long way off to me.
I THINK I got the decimals in the right place,