Patent ID: 8564312

Claim:
A fuel sensor comprising: an outer electrode that projects from an opening, which is formed in an upper inner wall of a fuel passage, into the fuel passage, wherein the fuel passage is adapted to conduct fuel generally in a horizontal direction, and the outer electrode includes a fuel chamber in an inside of the outer electrode; an inner electrode that is placed in the fuel chamber of the outer electrode; temperature sensing means for sensing a fuel temperature of fuel in the fuel chamber; and a sensing circuit that senses a fuel property of the fuel based on: an electrical property between the outer electrode and the inner electrode; and the fuel temperature, which is sensed with the temperature sensing means, wherein: the outer electrode includes: a blocking portion, which is configured into a tubular form and is placed on a lower side of the upper inner wall of the fuel passage; and at least one communication hole, which is placed on a lower side of the blocking portion and communicates between the fuel chamber and the fuel passage; and the blocking portion is adapted to limit intrusion of air bubbles, which flow along the upper inner wall of the fuel passage, into the at least one communication hole.