Route searching device

• US 8,793,067 B2
• Filed: 12/28/2009
• Issued: 07/29/2014
• Est. Priority Date: 12/28/2009
• Status: Expired due to Fees

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Mineta, Kenichi, Tsurutani, Taisuke, Takemasa, Koichiro, Aoki, Yoshinori
• Primary Examiner(s): To, Tuan C.
• Assistant Examiner(s): SMITH, ISAAC G
• Application Number:
  US12/648,090
• Publication Number:
  US 20110160993A1
• Time in Patent Office: 1,674 Days
• Field of Search: 701/22, 701/29.4, 701/50, 701/51, 701/54, 701/93, 701/95, 701/123, 701/200, 701/532, 701/56, 701/104, 701/33, 701/119, 701/301, 701/410, 701/415, 180/65.245, 180/165, 62/87, 622/39, 123/478
• US Class Current: 701/410
• CPC Class Codes: G01C 21/3469 Fuel consumption; Energy use; Emission aspects

Abstract

A route searching device according to an embodiment of the invention includes an estimated fuel consumption amount computing unit that computes an estimated fuel consumption amount of each interval constituting plural routes from a departure point to a destination and an optimum route selecting unit that selects a route in which a total of the estimated fuel consumption amount from the departure point to the destination is minimized. The estimated fuel consumption amount computing unit includes a cruise fuel consumption amount computing unit that computes a cruise fuel consumption amount for each interval by multiplying a distance of the interval and a fuel consumption rate determined according to an average vehicle speed a vehicle-speed fluctuation fuel consumption amount computing unit that computes a vehicle-speed fluctuation fuel consumption amount for each interval in each road category by multiplying the distance of the interval and the a fuel consumption rate, the fuel consumption rate being determined from an average vehicle speed and the road category of the interval and a gradient fuel consumption amount computing unit that computes a gradient fuel consumption amount for each interval by multiplying the distance of the interval and a fuel consumption rate determined according to a road average gradient. The estimated fuel consumption amount is obtained by adding the cruise fuel consumption amount, the gradient fuel consumption amount, and the vehicle-speed fluctuation fuel consumption amount.

Claims

1. 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.

2. The route searching device according to claim 1, wherein the vehicle-speed fluctuation fuel consumption rate for an expressway is greater than that for an urban road, and

a fuel consumption rate difference between the urban road and the expressway increases with decreasing average vehicle speed.

3. The route searching device according to claim 1, wherein the gradient fuel consumption rate is set to a greater value when the road average gradient increases, is set to a smaller value for the urban road compared to that for the express way in case of a rising gradient, and is set to a greater value for the urban road compared to that for the express way in case of a falling gradient.

4. The route searching device according to claim 1, wherein the processor is further configured to:

compute a fuel consumption amount of an air conditioner by multiplying an estimated running time in each interval and air-conditioner power consumption determined according to an ambient temperature; and

calculate the estimated fuel consumption amount by further adding the fuel consumption amount of the air conditioner to a sum of the cruise fuel consumption amount, the gradient fuel consumption amount, and the vehicle-speed fluctuation fuel consumption amount.

5. The route searching device according to claim 2, wherein the processor is further configured to:

compute a fuel consumption amount of an air conditioner by multiplying an estimated running time in each interval and air-conditioner power consumption determined according to an ambient temperature; and

calculate the estimated fuel consumption amount by further adding the fuel consumption amount of the air conditioner to a sum of the cruise fuel consumption amount, the gradient fuel consumption amount, and the vehicle-speed fluctuation fuel consumption amount.

6. The route searching device according to claim 3, wherein the processor is further configured to:

compute a fuel consumption amount of an air conditioner by multiplying an estimated running time in each interval and air-conditioner power consumption determined according to an ambient temperature; and

calculate the estimated fuel consumption amount by further adding the fuel consumption amount of the air conditioner to a sum of the cruise fuel consumption amount, the gradient fuel consumption amount, and the vehicle-speed fluctuation fuel consumption amount.

7. The route searching device according to claim 1, wherein the gradient fuel consumption rate has a value determined at least based on a vehicle weight, vehicle acceleration and deceleration, and a vehicle running resistance.