OK, fair warning: I am answering my own question and am not a engines person. So this could be wrong.
The real limit in the engine is how hot certain parts can get without breaking. This temperature is related to the gas temperature after combustion via the cooling system and the cylinder design (convective heat transfer between the gas and the cylinder wall). This proportionality will vary from engine to engine, but for arguments sake lets just assume that all engines have some magic gas temperature limit that is governing the cut-off ratio.
In a real engine there is not a clear cut-off ratio because the compression, combustion, and expansion steps all bleed into each other. However, the final gas temperature still sets the volume at which combustion stops which sets a cut-off ratio analogy.
The thing that is governing this is not really the valve timing as the rpm of the engine is remaining the same and the timing during each revolution does not change. What does change is the Air to Fuel Ratio (AFR). This is controlled by the fuel injection system based on how much oxygen is coming into the engine and at what temperature.
Lowering the inlet temperature does two things:
- It increases the mass flow of air through the engine.
- It decreases the temperature of the air prior to combustion.
Both of these things lead to a higher AFR at the same limiting gas temperature after combustion. The AFR is only controlled by the quantity of gas injected which is possible to dynamically control.
So, my answer is yes, it can be adjusted on the fly.
Again, that could be wrong.