It was long held that "inertia fill", resulting from intake charge velocity after BDC, despite the fact that the piston is going the wrong way, will improve VE.
Vizard believes that this is more rare and less effective than supposed, and has little value compared to the same intake event beginning earlier (advanced).
Blair suggests using "charge mass" (weight of molecules) rather than volume to make the VE, CR and CCP effects more clear.
