Patent ID: 8793067

Claim:
A route searching device that searches a vehicle running route, the route searching device comprising: at least one processor configured to: compute an estimated fuel consumption amount of each interval comprising a plurality of routes from a departure point to a destination; calculate a total of the estimated fuel consumption amount from the departure point to the destination and select a route in which the total of the estimated fuel consumption amount is minimized; compute a cruise fuel consumption amount for each interval by multiplying a distance of the interval and a cruise fuel consumption rate determined according to an average vehicle speed; compute a vehicle-speed fluctuation fuel consumption amount for each interval based on the distance of the interval and an energy consumption rate for a road category of the interval, wherein the energy consumption rate is determined based on the average vehicle speed and the road category of the interval by using predetermined data indicating an energy consumption per unit distance as a function of an average vehicle speed for each road category; compute a gradient fuel consumption amount for each interval by multiplying the distance of the interval and a gradient fuel consumption rate determined based on a road average gradient and the road category of the interval by using data indicating the gradient fuel consumption rate as a function of the road average gradient for each road category; and calculate the estimated fuel consumption amount by adding the cruise fuel consumption amount, the gradient fuel consumption amount, and the vehicle-speed fluctuation fuel consumption amount.