Abstract: The present invention is a variable blending dispenser for fluids, particularly for fuel dispensers. The dispenser controls variable valves according to volumetric data observed by flow meters on input lines to the dispenser, by calculating measuring error as the difference between desired blend ratio and the observed blend ratio calculated from volumes of blend components dispensed. The dispenser successively corrects the settings of the valves after dispensing predetermined volumes, the corrections determined by a volume based PID error function so that the total amount of each blend component is separately and accurately measured while providing the desired blend ratio.

Abstract: The present invention is a variable blending dispenser for fluids, particularly for fuel dispensers. The dispenser controls variable valves according to volumetric data observed by flow meters on input lines to the dispenser, by calculating measuring error as the difference between desired blend ratio and the observed blend ratio calculated from volumes of blend components dispensed. The dispenser successively corrects the settings of the valves after dispensing predetermined volumes, the corrections determined by a volume based PID error function so that the total amount of each blend component is separately and accurately measured while providing the desired blend ratio.