Comment on “A strategy of estimating fuel concentration in a direct liquid-feed fuel cell system” [Y.J. Chiu, H.C. Lien, Journal of Power Sources 159 (2006) 1162–1168]

The strategy for estimating the methanol concentration provided by Chiu and Lien [Y.J. Chiu, H.C. Lien, Journal of Power Sources 159 (2006) 1162–1168] overlooks the performance degradation (PD) of a direct methanol fuel cell (DMFC). In addition, the method may not be suitable in practice.