completion of a project to develop a new hydraulic actuator mechanism for its variable compression ratio (VCR) engine. Charles Mendler, the principal of Envera and the inventor of this particular approach to a VCR engine, provided the update on the project at the Department of Energy





Unlike that SAAB approach, the Envera mechanism fits inside the crankcase, and is expected to be faster and require less energy.

This also explains why the Honda concept acts on individual cylinders – the CR can be raised on the cylinder that is on intake, with little force or power.
OK so, have electronically controlled valves and set the valves for “vacuum pump” for about 1 revolution and just suck the crank up a notch or 2.