Patent ID: 8666576

Claim:
A method for calculating a Distance to Empty (DTE) in an electric vehicle, comprising: calculating, by at least one controller, a past driving average fuel efficiency; calculating, by at least one controller, an air conditioning average energy consumption rate during at least one past driving cycle; calculating, by at least one controller, a past driving average fuel efficiency which assumes an air conditioning apparatus is not used from the past driving average fuel efficiency and the air conditioning average energy consumption rate; calculating, by at least one controller, a current driving fuel efficiency; blending, by at least one controller, the past driving average fuel efficiency assumes the air conditioning apparatus is not used and the current driving fuel efficiency; and calculating the DTE from the blended driving fuel efficiency, wherein the blending of the past driving average fuel efficiency and the current driving fuel efficiency is calculated by applying a weighted average method, wherein the weighted average method applies a weighted value to the past driving average fuel efficiency which assumes the air conditioning apparatus is not used and the current driving fuel efficiency, the average fuel efficiency is expressed as: R 0={ A 1× a [0]+ A 2× a [1]+ A 3× a [2] . . . + An×a [ n− 1]+ B×b [0]}/( A 1+ A 2+ A 3+ . . . An+B ) where R0 is the past driving average fuel efficiency, A1, A2, A3, An and B denote weighted value, a[0], a[1], a[2], and a[n−1] denote fuel efficiencies of each driving cycle, and b[0] denotes a certified fuel efficiency.