Patent ID: 8246817

Claim:
In a vehicle having an electric fuel cell and coolant system, said coolant system including: a deionization filter including a housing having an inlet and an outlet, wherein a bed of negatively-charged cation and positively-charged anion exchange resin beads is contained within said housing, between the inlet and outlet; a pump; a thermal exchange device; and a coolant circulation network fluidically connecting said fuel cell, deionization filter, pump, and said thermal exchange device, said circulation network including: a coolant inlet line fluidically connected to said inlet; and a coolant outlet line fluidically connected to said outlet; the improvement comprising: a conductivity metering system including: an inlet conductivity meter provided in said coolant inlet line; an outlet conductivity meter provided in said coolant outlet line; and a conductivity analyzer box electrically connected to said inlet conductivity meter and said outlet conductivity meter for receiving signals from said meters; wherein, coolant is continuously circulated through said coolant system and through said deionization filter, where negative ions are removed from said coolant as it passes through said bed of negatively-charged cation and positively-charged anion exchange resin beads, the conductivity of coolant is measured before it enters said deionization filter using said inlet conductivity meter to obtain a first conductivity signal, the conductivity of coolant is measured after it exits said deionization filter using said outlet conductivity meter to obtain a second conductivity signal, and the difference in said first and second conductivity signals is computed in said conductivity analyzer box, to determine the functional efficacy of the deionization filter based on the difference in said first and second conductivity signals.