Feedforward control of the volume flow in a hydraulic system

摘要

A thermal sub-system for a fuel cell system that employs an algorithm using feed-forward control. The algorithm calculates a Reynolds number based on the velocity of the cooling fluid, a diameter of a coolant loop pipe and a kinematic viscosity (temperature) of a cooling fluid. The algorithm also uses a pressure loss number based on the Reynolds number and a position of a by-pass valve. The algorithm also defines a pressure loss value based on the pressure loss number, the density of the cooling fluid and the velocity of the cooling fluid. The algorithm then calculates a delivery head value based on the pressure loss value, the fluid density and a gravitational acceleration. The algorithm then uses the delivery head value and a predetermined set-point value of the volume flow to determine a desired pump speed based on the current operating parameters of the system.

主权项

1. A system for providing feed-forward flow control of a fluid being pumped through a pipe by a pump, said system comprising:
a system resistance characteristic processor, said system resistance characteristic processor programmed to:
calculate a Reynolds number based on a velocity of the fluid, a diameter of the pipe and a kinematic viscosity of the fluid;calculate a pressure loss value based on a pressure loss number, a density of the fluid and the velocity of the fluid, wherein the pressure loss number is a function of the Reynolds number; andcalculate a delivery head value based on the pressure loss value, the density of the fluid and a gravitational acceleration of the fluid; and a pump characteristic processor, said pump characteristic processor programmed to determine a desired pump speed based on the delivery head value and a predetermined volume flow set-point of the fluid.