the systems having variable, i.e. adjustable, cross-sectional areas, chambers of variable volume, or like variable means

Full Title

Use of kinetic or wave energy of charge in induction systems, or of combustion residues in exhaust systems, for improving quantity of charge or for increasing removal of combustion residues > in exhaust systems only, e.g. for sucking-off combustion gases > the systems having variable, i.e. adjustable, cross-sectional areas, chambers of variable volume, or like variable means