System and method for measuring liquid viscosity in a fluid delivery system

The present invention includes systems and methods for determining the viscosity of a fluid within a fluid flow path. Such method may comprise flowing fluid through the fluid flow path and past a fixed flow restriction therein. The method may also comprise first sensing of a fluid pressure within the fluid flow path at a selected location upstream of the flow restriction. The method may also include limiting fluid flow in the fluid flow path upstream of such selected location. The method may further comprise second sensing of a fluid pressure within the fluid flow path at such selected location after such limiting. Such method includes determining the viscosity of the fluid based, at least in part, on any pressure difference from such first and second sensing.