WO2010116481A1

WO2010116481A1 - Fuel consumption estimating device, fuel consumption estimating method, fuel consumption estimating program and recording medium

Info

Publication number: WO2010116481A1
Application number: PCT/JP2009/057071
Authority: WO
Inventors: 雅俊柳平; 光男安士
Original assignee: パイオニア株式会社
Priority date: 2009-04-06
Filing date: 2009-04-06
Publication date: 2010-10-14
Also published as: JPWO2010116481A1

Abstract

An estimation unit (101) of a fuel consumption estimating device (100) estimates the fuel consumption of a vehicle at a predetermined point. An acquisition unit (103) acquires weather information such as atmospheric temperature information and atmospheric pressure information at the predetermined point. A correction unit (104) corrects the estimated fuel consumption estimated by the estimation unit (101) on the basis of the weather information. When the correction is made using the atmospheric temperature information, the correction unit (104) reduces the value of the estimated fuel consumption when the atmospheric temperature at the predetermined point is higher than a preset reference temperature, and increases the value of the estimated fuel consumption when the atmospheric temperature is lower than the reference temperature.

Description

Fuel consumption estimation device, fuel consumption estimation method, fuel consumption estimation program, and recording medium

The present invention relates to a fuel consumption estimation device, a fuel consumption estimation method, a fuel consumption estimation program, and a recording medium for estimating fuel consumption of a vehicle. However, the use of the present invention is not limited to the above-described fuel consumption estimation device, fuel consumption estimation method, fuel consumption estimation program, and recording medium.

Conventionally, various methods have been devised for estimating the fuel consumption of a vehicle during traveling (see, for example, Patent Document 1 below). The following Patent Document 1 is a technique for searching for a route with less fuel consumption, storing fuel consumption information corresponding to the traveling speed for each vehicle type, and using the link data and the fuel consumption information to minimize the fuel consumption. Calculate the route of. Patent Document 1 below discloses a method in which fuel consumption information collected from a fuel consumption detection sensor is stored in association with a traveling speed and used for fuel consumption estimation from the next time onward.

FIG. 10 is a graph showing the relationship between vehicle speed and fuel consumption. In FIG. 10, the vertical axis represents fuel consumption, and the horizontal axis represents travel speed. It is known that the relationship between the traveling speed and the fuel consumption is expressed by the following equation, for example.
fc = m ₁ + m ₂ · x ² + m ₃ · x ³ + m ₄ · x
Here, fc is the fuel consumption per unit time, x is the average speed of the unit section, and m ₁ to m ₄ are constants.

JP 2005-172582 A

However, the above-described conventional technology does not consider the influence of the weather environment around the vehicle when estimating the fuel consumption. For this reason, in the above-described conventional technology, there is a problem that an error between the estimated fuel consumption and the actual fuel consumption becomes large. For example, it is known that vehicle fuel consumption is affected by temperature. FIG. 11 is a graph schematically showing the monthly fuel consumption in the same vehicle. In FIG. 11, the vertical axis represents fuel consumption (travel distance per unit amount of fuel), and the horizontal axis represents the moon. In FIG. 11, the solid line represents the fuel consumption when the fuel consumption due to the use of the air conditioner is not taken into account, and the dotted line represents the fuel consumption when the fuel consumption due to the use of the air conditioner is taken into consideration.

As shown in FIG. 11, the fuel consumption is good around July when the temperature is high, and the fuel consumption is bad around January when the temperature is low. In addition, since the air is cooled by the air conditioner in the high temperature season, the actual fuel consumption slightly decreases as shown by the dotted line. On the other hand, since heaters are used in low-temperature seasons, the use of air conditioners has little effect on fuel consumption.

In addition to temperature, it is known that factors such as weather, atmospheric pressure, and wind influence fuel efficiency. Specifically, for example, the road surface becomes slippery when it rains, and the fuel consumption decreases. Moreover, since the density of air is low in a place where the atmospheric pressure is low, fuel consumption is reduced. Further, when the wind is blowing in the same direction as the traveling direction of the vehicle, the fuel efficiency is improved, but when the wind is blowing in the direction opposite to the traveling direction of the vehicle, the fuel efficiency is decreased. In the prior art described above, since the influence of such a weather environment is not taken into consideration, an error between the estimated fuel consumption and the actual fuel consumption has increased.

In order to solve the above-described problems and achieve the object, a fuel consumption estimation apparatus according to the invention of claim 1 is configured to estimate a fuel consumption amount of a vehicle at a predetermined point, and acquire weather information at the predetermined point. And correction means for correcting the fuel consumption estimated by the estimation means based on the weather information acquired by the acquisition means.

According to a nineteenth aspect of the present invention, there is provided an estimation method for estimating fuel consumption of a vehicle at a predetermined point, an acquisition step for acquiring weather information at the predetermined point, and the acquisition step acquired at the acquisition step. And a correction step of correcting the fuel consumption estimated in the estimation step based on weather information.

The fuel consumption estimation program according to the invention of claim 20 causes a computer to execute the fuel consumption estimation method according to claim 19.

Further, a recording medium according to the invention of claim 21 is characterized in that the fuel consumption estimation program according to claim 20 is recorded in a computer-readable state.

It is a block diagram which shows the functional structure of the fuel consumption estimation apparatus concerning embodiment. It is a flowchart which shows the procedure of the fuel consumption estimation process by a fuel consumption estimation apparatus. It is a block diagram which shows the hardware constitutions of a navigation apparatus. It is explanatory drawing which shows an example of the weather information database which a navigation apparatus has. It is explanatory drawing which shows the other example of the weather information database which a navigation apparatus has. It is explanatory drawing which shows typically the wind which blows with respect to a vehicle, and the advancing direction of a vehicle. It is a flowchart which shows the procedure of the correction process of the estimated fuel consumption amount by a navigation apparatus. It is a flowchart which shows the other procedure of the correction process of the estimated fuel consumption amount by a navigation apparatus. It is a flowchart which shows the other procedure of the correction process of the estimated fuel consumption amount by a navigation apparatus. It is a graph which shows the relationship between a vehicle speed and fuel consumption. It is a graph which shows typically the monthly fuel consumption in the same vehicle.

Hereinafter, preferred embodiments of a fuel consumption estimation device, a fuel consumption estimation method, a fuel consumption estimation program, and a recording medium according to the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment)
FIG. 1 is a block diagram illustrating a functional configuration of the fuel consumption estimation apparatus according to the embodiment. The fuel consumption estimation apparatus 100 according to the embodiment includes an estimation unit 101, a route setting unit 102, an acquisition unit 103, and a correction unit 104. The estimation unit 101 estimates the fuel consumption of the vehicle at a predetermined point. The predetermined point is an arbitrary point on the road on which the vehicle travels. For example, the predetermined point is a point included in a route set by the route setting unit 102 described later. For example, when the vehicle travels through a predetermined point, the estimating unit 101 estimates the fuel consumption amount at the predetermined point. Further, for example, the estimation unit 101 may estimate the fuel consumption of the vehicle in a predetermined section on the route including the predetermined point before the vehicle starts traveling on the route. The predetermined section may be the entire route or a part of the route. Hereinafter, the point or section where the fuel consumption estimation apparatus 100 estimates the fuel consumption is referred to as “estimation target place”.

As described above, the estimation of the fuel consumption by the estimation unit 101 mainly has the following two forms. The first mode is a mode in which fuel consumption is estimated using vehicle speed information or the like when the vehicle is actually traveling. In the second mode, when a route is set by a route setting unit 102 described later, the fuel consumption of the vehicle on the route (or a part thereof) is estimated before the actual driving is started.

Further, the fuel consumption estimated by the estimation unit 101 includes an instantaneous fuel consumption amount indicating the fuel consumption amount per unit time and a section fuel consumption amount indicating the fuel consumption amount in a predetermined section. The estimation unit 101 mainly estimates the instantaneous fuel consumption amount in the first embodiment described above, and mainly estimates the section fuel consumption amount in the second embodiment. The section fuel consumption amount can be calculated not only by calculating the average speed or distance of the section, but also by integrating the instantaneous fuel consumption amount in the section.

The estimation unit 101 estimates the fuel consumption by, for example, obtaining a solution of a predetermined regression equation using the traveling speed of the vehicle as a variable. In the case of the first embodiment described above, the estimation unit 101 estimates the fuel consumption amount using, for example, actual vehicle speed information. Moreover, in the case of the 2nd form, the estimation part 101 estimates fuel consumption, for example using the average speed information in each link on a path | route.

The route setting unit 102 sets a route to the destination point. The route setting unit 102 sets a route by searching for a route to a destination point designated by the user, for example.

The acquisition unit 103 acquires weather information of the estimation target point. In addition, when the estimation unit 101 estimates the fuel consumption of the vehicle in a predetermined section on the route, the acquisition unit 103 acquires weather information in the predetermined section on the route. Examples of the weather information acquired by the acquisition unit 103 include temperature information, atmospheric pressure information, humidity information, wind speed information, wind direction information, and precipitation information.

The acquisition unit 103 acquires the weather information by reading the weather information from the database 110 in which past weather information at the representative point is recorded, for example. The representative point is, for example, a point where a prefectural office or a weather station is located.

The correction unit 104 corrects the fuel consumption estimated by the estimation unit 101 (hereinafter referred to as “estimated fuel consumption”) based on the weather information acquired by the acquisition unit 103. For example, when correcting the estimated fuel consumption amount using the temperature information, the correction unit 104 decreases the estimated fuel consumption amount value when the temperature of the estimation target site is higher than a predetermined reference temperature, When the local temperature is lower than the reference temperature, the estimated fuel consumption amount is increased. This is because within a certain temperature range, the fuel efficiency improves as the temperature increases, and the fuel efficiency decreases as the temperature decreases. In this specification, “good fuel consumption” means that the fuel consumption per unit distance is relatively small, and “bad fuel consumption” means that the fuel consumption per unit distance is relatively large. Say.

Further, when correcting the estimated fuel consumption amount using the atmospheric pressure information, the correction unit 104 reduces the estimated fuel consumption amount value when the estimated atmospheric pressure of the target area is higher than a predetermined reference atmospheric pressure, When the atmospheric pressure is lower than the reference atmospheric pressure, the estimated fuel consumption amount is increased. This is because, within a certain atmospheric pressure range, the fuel efficiency improves as the atmospheric pressure increases, and the fuel efficiency decreases as the atmospheric pressure decreases.

Further, when correcting the estimated fuel consumption amount using the temperature information and the humidity information, the correction unit 104 determines that the estimated fuel consumption amount is higher when the temperature and humidity of the estimation target site are higher than the predetermined reference temperature and reference humidity. Increase the value of. This is because when the temperature and humidity are high, the user feels uncomfortable (an environment with a high discomfort index), and the operating rate of the air conditioner is considered to increase.

Further, when correcting the estimated fuel consumption amount based on the wind speed information and the wind direction information, the correction unit 104 calculates the air resistance that the vehicle receives due to the wind at the estimation target site, and the greater the air resistance that the vehicle receives, the more the estimated fuel consumption. Increase the quantity value. This is because it is considered that the greater the air resistance received by the vehicle, the more kinetic energy is required for traveling and the more fuel is consumed.

Further, when correcting the estimated fuel consumption amount using the precipitation information, the correction unit 104 increases the value of the estimated fuel consumption amount when the precipitation amount in the estimation target area is larger than a predetermined reference amount. This is because when there is precipitation, the friction coefficient of the road surface decreases, and it is considered that a large amount of fuel is consumed during acceleration / deceleration.

Further, the correction unit 104 may estimate the weather condition of the estimation target site from the weather information at the weather observation point and use it for correcting the fuel consumption even if the weather information itself of the estimation target site is not obtained. . For example, when the temperature information at the temperature measurement point in the vicinity of the estimation target site is obtained, the correction unit 104 calculates the temperature information of the estimation target site based on the difference between the elevation of the temperature measurement point and the elevation of the estimation target site. presume. Further, when the atmospheric pressure information at the atmospheric pressure measurement point in the vicinity of the estimation target site is obtained, the correction unit 104 calculates the temperature information of the estimation target site based on the difference between the elevation of the temperature measurement point and the estimation target site. presume.

FIG. 2 is a flowchart showing a procedure of fuel consumption estimation processing by the fuel consumption estimation device. The flowchart of FIG. 2 shows a process in a case where fuel consumption is corrected using temperature information as an example of weather information. Further, the flowchart of FIG. 2 is a form in which the fuel consumption amount at a predetermined point is estimated when the vehicle is actually traveling. In the fuel consumption estimation device 100, first, the estimation unit 101 estimates the fuel consumption amount at the estimation target point (step S201). Next, the fuel consumption estimation apparatus 100 acquires the temperature information of the estimation target point by the acquisition unit 103 (step S202). In addition, when the temperature information itself of the estimation target point cannot be acquired, the temperature information at the temperature measurement point in the vicinity of the estimation target point is acquired.

Subsequently, the fuel consumption estimation apparatus 100 determines whether or not the temperature at the estimation target point is higher than the reference temperature by the correction unit 104 (step S203). When the temperature of the estimation target point is higher than the reference temperature (step S203: Yes), the correction unit 104 decreases the estimated fuel consumption amount estimated in step S201 (step S204), and ends the processing according to this flowchart. To do. On the other hand, when the temperature at the estimation target point is lower than the reference temperature (step S203: No), the correction unit 104 increases the value of the estimated fuel consumption estimated in step S201 (step S205), and the processing according to this flowchart. Exit.

As described above, according to the fuel consumption estimation device 100, the estimated fuel consumption is corrected using the weather information. Thereby, the fuel consumption can be estimated in consideration of the influence of the weather, and the prediction accuracy of the fuel consumption can be improved. Further, according to the fuel consumption estimation device 100, correction is performed in consideration of various weather factors such as air temperature, atmospheric pressure, humidity, wind speed, wind direction, and precipitation, so that an error between the estimated fuel consumption and the actual fuel consumption is further increased. Can be small.

In addition, if the fuel consumption estimation apparatus 100 acquires weather information from a database that records past weather information at representative points, the above-described correction can be performed by incorporating the database into the conventional fuel consumption estimation apparatus. For this reason, for example, even in a fuel consumption estimation device that does not have a communication function, correction in consideration of weather information can be performed, and the estimation accuracy of fuel consumption can be improved at low cost.

Hereinafter, examples of the present invention will be described. In the present embodiment, an example in which the present invention is applied using the navigation device 300 mounted on a vehicle as the fuel consumption estimation device 100 will be described.

(Hardware configuration of navigation device 300)
First, the hardware configuration of the navigation device 300 will be described. FIG. 3 is a block diagram illustrating a hardware configuration of the navigation apparatus. In FIG. 3, a navigation device 300 includes a CPU 301, ROM 302, RAM 303, magnetic disk drive 304, magnetic disk 305, optical disk drive 306, optical disk 307, audio I / F (interface) 308, microphone 309, speaker 310, input device 311, A video I / F 312, a display 313, a camera 314, a communication I / F 315, a GPS unit 316, and various sensors 317 are provided. Each component 301 to 317 is connected by a bus 320.

First, the CPU 301 governs overall control of the navigation device 300. The ROM 302 records programs such as a boot program and a route search program. The RAM 303 is used as a work area for the CPU 301. That is, the CPU 301 controls the entire navigation device 300 by executing various programs recorded in the ROM 302 while using the RAM 303 as a work area.

The magnetic disk drive 304 controls the reading / writing of the data with respect to the magnetic disk 305 according to control of CPU301. The magnetic disk 305 records data written under the control of the magnetic disk drive 304. As the magnetic disk 305, for example, an HD (hard disk) or an FD (flexible disk) can be used.

The optical disk drive 306 controls reading / writing of data with respect to the optical disk 307 according to the control of the CPU 301. The optical disk 307 is a detachable recording medium from which data is read according to the control of the optical disk drive 306. As the optical disc 307, a writable recording medium can be used. In addition to the optical disk 307, an MO, a memory card, or the like can be used as a removable recording medium.

Examples of information recorded on the magnetic disk 305 and the optical disk 307 include content data and map data. The content data is, for example, music data, still image data, moving image data, or the like. The map data includes background data that represents features (features) such as buildings, rivers, and the ground surface, and road shape data that represents the shape of the road. The map data consists of multiple data files divided by district. It is configured.

The voice I / F 308 is connected to a microphone 309 for voice input and a speaker 310 for voice output. The sound received by the microphone 309 is A / D converted in the sound I / F 308. From the speaker 310, a sound obtained by D / A converting a predetermined sound signal in the sound I / F 308 is output.

The input device 311 includes a remote controller, a keyboard, a touch panel, and the like provided with a plurality of keys for inputting characters, numerical values, various instructions, and the like. The input device 311 may be realized by any one form of a remote control, a keyboard, and a touch panel, but may be realized by a plurality of forms.

The video I / F 312 is connected to the display 313. Specifically, the video I / F 312 is output from, for example, a graphic controller that controls the entire display 313, a buffer memory such as a VRAM (Video RAM) that temporarily records image information that can be displayed immediately, and a graphic controller. And a control IC for controlling the display 313 based on the image data to be processed.

The camera 314 captures images inside or outside the vehicle. The image may be either a still image or a moving image. For example, a camera 314 captures a landscape or a feature outside the vehicle, a passenger inside the vehicle, etc., and the captured image is recorded on the magnetic disk 305 or the like via the video I / F 312. Recording is performed on a recording medium such as an optical disk 307.

The display 313 displays icons, cursors, menus, windows, or various data such as characters and images. On the display 313, the map data described above is drawn two-dimensionally or three-dimensionally. The map data displayed on the display 313 can be displayed with a mark representing the current position of the vehicle on which the navigation device 300 is mounted. The current position of the vehicle is calculated by the CPU 301. As the display 313, for example, a TFT liquid crystal display, an organic EL display, or the like can be used.

The communication I / F 315 is wirelessly connected to a communication network such as the Internet, and also functions as an interface between the communication network and the CPU 301. The communication I / F 315 transmits and receives data to and from nearby electronic devices by short-range communication such as infrared communication or Bluetooth (registered trademark). Further, the communication I / F 315 receives broadcast waves such as television and radio. Broadcast waves received by the communication I / F 315 are output as audio information and image information to the speaker 310 and the display 313 via the audio I / F 308 and the video I / F 312.

The GPS unit 316 receives radio waves from GPS satellites and outputs information indicating the current position of the vehicle. The output information of the GPS unit 316 is used when the CPU 301 calculates the current position of the vehicle together with output values of various sensors 317 described later. The information indicating the current position is information for specifying one point on the map data such as latitude / longitude and altitude.

The various sensors 317 output information for determining the position and behavior of the vehicle, such as a vehicle speed sensor, an acceleration sensor, and an angular velocity sensor. The output values of the various sensors 317 are used by the CPU 301 to calculate the current position of the vehicle and the amount of change in speed and direction.

Note that the estimation unit 101, the route setting unit 102, the acquisition unit 103, and the correction unit 104 of the fuel consumption estimation device 100 illustrated in FIG. 1 are the ROM 302, RAM 303, magnetic disk 305, optical disk 307, and the like in the navigation device 300 illustrated in FIG. The CPU 301 executes a predetermined program using the program and data recorded in the above, and realizes its function by controlling each part in the navigation device 300.

(Outline of fuel consumption estimation processing by the navigation device 300)
Next, fuel consumption estimation processing by the navigation device 300 will be described. In the following description, “fuel consumption” and “fuel consumption” have the same meaning. In general, the navigation device 300 has a function of searching for a route connecting a departure point and a destination point set by a designated user, but the navigation device 300 according to the present embodiment additionally searches for a route. It has a function of estimating the amount of fuel consumed during traveling on the route. More specifically, the navigation apparatus 300 estimates a fuel consumption amount using a general fuel consumption prediction formula, and further corrects the estimated fuel consumption amount in consideration of weather conditions on the route. Since the fuel consumption varies depending on weather conditions such as temperature and atmospheric pressure, the estimation accuracy of the fuel consumption can be improved by considering these factors.

[Calculation method of estimated fuel consumption]
First, a method for calculating the fuel consumption before correction will be described. Various methods are known for estimating the fuel consumption. In general, the fuel consumption is estimated by obtaining a solution of a regression equation using the traveling speed of the vehicle as a variable. Although the fuel consumption estimation method in the navigation device 300 is also arbitrary, for example, the fuel consumption is calculated using the following equation (1). The fuel consumption calculated using the following formula (1) is referred to as “estimated fuel consumption”.

The above equation (1) uses the speed x as an independent variable, but since the actual traveling speed is not known before starting traveling, the average traveling speed on the route is defined as the speed x. The average travel speed is calculated, for example, by dividing the route distance by the average time required to pass the route. For example, average required time data recorded as a database in the navigation device 300 is used as the average required time required to pass a certain section. The route may be divided into a predetermined number of sections (for example, for each link), and the average traveling speed may be calculated for each section.

Further, since the estimated fuel consumption amount calculated by the above equation (1) is the instantaneous fuel consumption amount, the fuel consumption amount in the entire estimation target section can be calculated by integrating the instantaneous fuel consumption amount in the estimation target section. Further, the above equation (1) is an equation for estimating the fuel consumption before the start of traveling, but the correction method described below is also applied when estimating the fuel consumption during actual traveling. be able to.

The navigation device 300 can obtain the acceleration information and the speed information of the vehicle in real time when the vehicle starts traveling, and calculate the fuel consumption amount reflecting the actual traveling state. Specifically, the navigation apparatus 300 calculates the fuel consumption amount in consideration of the actual speed and acceleration using the following formula (2).

In the above formula (2), time (h) and second (s) are mixedly used as a unit representing time, but this uses speed (km / h) as a unit of speed. This is because the second (s) is adopted as the unit time for estimating the fuel consumption. When it is desired to align these units, an appropriate calculation may be performed on each numerical value. Further, since the estimated fuel consumption amount calculated by the above equation (2) is the instantaneous fuel consumption amount, the fuel consumption amount in the entire estimation target section can be calculated by integrating the instantaneous fuel consumption amount in the estimation target section.

[Method for correcting estimated fuel consumption]
Next, a method for correcting the estimated fuel consumption calculated as described above will be described. The navigation device 300 corrects the estimated fuel consumption amount in consideration of the temperature, the atmospheric pressure, the humidity, the wind direction / wind speed, and the precipitation amount as weather factors that change the fuel consumption amount. Moreover, since these meteorological factors are closely related to altitude, the navigation apparatus 300 also considers altitude information of the estimation target section.

The navigation device 300 stores a database as shown in FIGS. 4 and 5 on the magnetic disk 305 or the optical disk 307, and acquires weather information of the estimation target section with reference to this database. FIG. 4 is an explanatory diagram illustrating an example of a weather information database included in the navigation device. In the database 400 of FIG. 4, representative city name information 401, position information 402, altitude information 403, and average temperature information 404 are recorded. Here, the representative city is a city with a prefectural office location or a meteorological station.

The navigation device 300 refers to the position information of the route (estimation target section) for estimating the fuel efficiency and searches for the nearest representative city at each point on the route. The search for the nearest representative city is performed, for example, by selecting the nearest representative city from an arbitrary point in the link for each link. Then, the average temperature information 404 of the nearest representative city is read and used as temperature information at each point on the route. In FIG. 4, the average temperature information 404 is shown as average temperature data for each month. However, the average temperature information 404 is not limited to this. For example, the average temperature information 404 may be daily average temperature data or hourly average temperature data. May be.

FIG. 5 is an explanatory diagram showing another example of a weather information database included in the navigation device. FIG. 5 is a part of a database in which past weather information of a representative city is accumulated, and the actual measured values of the representative city at a specific date and time in the past are recorded. The data 500 in FIG. 5 is actual weather measurement values in City A on August 15, 2008, and includes hourly precipitation information 501, temperature information 502, wind information 503 as wind speed information 503a and wind direction information 503b, and sunshine duration. Snowfall information 505a and snowfall information 505b are recorded as information 504 and snow information 505, respectively. The navigation device 300 corrects the fuel consumption using these data.

Further, the navigation device 300 may receive weather information distributed from a weather station or the like via the communication I / F 315, for example. Further, for example, a measuring device for measuring weather information such as temperature, atmospheric pressure, and humidity is provided in the navigation device 300 or in the vehicle of the navigation device 300, and the data measured by this device is used to estimate the estimated fuel consumption. It may be used.

(Correction method using temperature information)
Next, a method for correcting the estimated fuel consumption amount considering each weather factor will be described. Note that the navigation device 300 may perform correction in consideration of all the weather factors listed below, or may perform correction in consideration of only arbitrary weather factors.

First, a correction method using temperature information will be described. Generally, within a certain temperature range, the fuel efficiency improves as the temperature increases, and the fuel efficiency decreases as the temperature decreases. Using this, the navigation device 300 corrects the estimated fuel consumption amount as shown in the following equation (3).
E = h ₁ · E ₀
h ₁ = 1 + β (T−T _ref ) (3)
Here, E is the corrected fuel consumption, E ₀ is the estimated fuel consumption, h ₁ is a correction factor considering the temperature, T is the temperature of the estimation target section, T _ref is the reference temperature (for example, 15 ° C.), and β is This is a correction value adjustment coefficient. The coefficient β is a coefficient for keeping the correction amount of the estimated fuel consumption amount due to the temperature within a certain range. For example, the maximum temperature is defined as 40 ° C. and the minimum temperature is −15 ° C., and the correction amount range is ± 8%. Is defined as β (40−15) = − 0.08, that is, β = −0.0032.

Further, in the above equation (3), when the temperature data read from the database of FIG. 4 is used as the temperature data of the estimation target section, the temperature data is taken into account the difference between the elevation of the representative city and the elevation of each point on the route. May be corrected. It is known that the temperature decreases by 0.6 ° C. for every 100 m elevation. For example, if the altitude of a representative point is 400m above sea level, the temperature is 20.0 ° C, and the altitude of a certain point on the route is 800m above sea level, the temperature at that point is 17.6 ° C. And may be applied to the above equation (2).

Also, when searching for a route, the passing time of each point on the route can be predicted. Using this, the average temperature information of the representative point at that time may be acquired and used for the above-described correction.

Further, when a temperature sensor is built in the navigation device 300, the temperature information measured by the temperature sensor may be used for the correction described above. This temperature sensor is installed for the purpose of preventing the magnetic disk 305 from rotating or reducing the number of clocks of the CPU 301 when, for example, a device in the navigation apparatus 300 becomes hot. When using a temperature sensor built in the navigation device 300, for example, the temperature is measured when the navigation device 300 is activated. This is because the air temperature is measured before the temperature of the device in the navigation device 300 rises. Further, for example, when the distance between the representative cities is more than a predetermined distance, the temperature information obtained in this way may be used for correction.

(Correction method using barometric pressure information)
Next, a correction method using atmospheric pressure information will be described. In general, within a certain atmospheric pressure range, the fuel efficiency improves as the atmospheric pressure increases, and the fuel efficiency decreases as the atmospheric pressure decreases. Using this, the navigation device 300 corrects the estimated fuel consumption amount as shown in the following equation (4).
E = h ₂ · E ₀
h ₂ = 1 + β (P−P _ref ) (4)
Here, E is the corrected fuel consumption, E ₀ is the estimated fuel consumption, h ₂ is a correction factor considering the atmospheric pressure, P is the atmospheric pressure of the estimation target section, and P _ref is the reference atmospheric pressure (for example, 1 atmospheric pressure = 1013.25 hPa) ), Β is a coefficient for adjusting the correction value.

Note that the atmospheric pressure P in the estimation target section is calculated based on the following equation (5).
P = P ₀ (1-0.0065 m / (T + 273.15)) 5.257 (5)
Here, P ₀ is the atmospheric pressure at an altitude of 0 m, T is the temperature of the estimation target section, and m is the elevation of the estimation target section.

Further, it is generally known that the fuel consumption is reduced even at a high altitude. In consideration of this, the estimated fuel consumption amount may be corrected as in the following formula (6).
E = h ₃ · E ₀
h ₃ = 1 + β · m / 100 (6)
Here, E is the corrected fuel consumption, E ₀ is the estimated fuel consumption, h ₃ is a correction factor considering the altitude, m is the altitude of the estimation target section, and β is a coefficient for adjusting the correction value. In the above formula (5), the value of the coefficient β is set to 0.01 when the fuel consumption is deteriorated by 1% at an altitude of 100 m, for example.

(Correction method using humidity information)
Next, a correction method using humidity information will be described. In general, it is known that human beings feel uncomfortable when the humidity and temperature exceed a certain level. For example, the discomfort index is known as a numerical value of discomfort associated with an increase in humidity and temperature. When the humidity and temperature rise, the user usually operates the air conditioner of the vehicle. Using this, the navigation apparatus 300 corrects the estimated fuel consumption amount to be large in a time zone in which the past average humidity and average temperature are equal to or higher than a certain value, assuming that the air conditioner is operating. If only the temperature information is used without using the humidity information and the temperature is equal to or higher than the reference temperature, the correction may be performed assuming that the air conditioner is operating.

(Correction method using wind information)
Next, a correction method using wind information will be described. In general, it is known that the greater the air resistance received by a vehicle, the more kinetic energy is required for traveling and the more fuel is consumed. Therefore, the navigation apparatus 300 corrects the estimated fuel consumption amount using the wind speed information and the wind direction information in the estimation target section.

FIG. 6 is an explanatory diagram schematically showing the wind blowing on the vehicle and the traveling direction of the vehicle. When the traveling speed of the vehicle 600 is v, the wind speed is v _w , and the angle between the traveling direction of the vehicle and the wind direction is θ, the traveling direction component of the wind speed can be represented by v _w cos θ. For example, if the fuel consumption estimation equation is a regression equation with the vehicle traveling speed v as a variable, the value of the traveling speed v to be substituted into the regression equation is (v−v _w cos θ), so that the wind It is possible to calculate the fuel consumption considering the influence on the vehicle (the air resistance experienced by the vehicle).

(Correction method using precipitation information)
Next, a correction method using precipitation information will be described. In general, when there is precipitation, the friction coefficient of the road surface decreases, and a lot of fuel is consumed during acceleration / deceleration. Using this, the navigation device 300 increases the value of the estimated fuel consumption when there is a predetermined amount or more of precipitation in the estimation target section. Specifically, it is known that when there is precipitation, the fuel consumption is reduced by about 10%. For this reason, for example, when there is precipitation, if the fuel consumption before correction is multiplied by 1.1, correction in consideration of precipitation can be performed. In addition, the acquisition of precipitation information includes, for example, the actual precipitation information in the estimation target section via the communication I / F 315, and the precipitation at the predicted passage time for each link on the route when the route is searched. Probability information may be acquired and used for correction.

[Correction procedure]
Next, a procedure for correcting the estimated fuel consumption amount by the navigation device 300 will be described. In the following, 1) When estimating and correcting the fuel consumption during the route search, 2) When estimating the fuel consumption during the route search and continuously correcting after the start of traveling, 3) Fuel consumption during traveling Each of the three patterns when estimating and correcting the quantity will be described.

First, 1) A case where fuel consumption is estimated and corrected during route search will be described. For example, when the fuel consumption amount in a predetermined section (for example, a route to a destination point designated by the user) is estimated using the above formula (1), for example, only the weather information that can be acquired at that time is obtained. This method is used to correct the estimated fuel consumption.

FIG. 7 is a flowchart showing a procedure for correcting the estimated fuel consumption amount by the navigation device. In the flowchart of FIG. 7, the navigation device 300 first waits until a section for estimating fuel consumption (estimation target section) is designated (step S701: No loop). The estimation target section is specified by searching for a route to a predetermined destination point, for example.

When the estimation target section is designated (step S701: Yes), the navigation apparatus 300 estimates the fuel consumption in the estimation target section (step S702). This fuel consumption is calculated based on, for example, the average traveling speed on the route. Next, the navigation apparatus 300 extracts the representative city closest to each point in the estimation target section (step S703). For example, the navigation device 300 selects a representative city closest to any point in the link for each link on the route.

Subsequently, the navigation device 300 acquires a predicted passage time when traveling in the estimation target section (step S704). Then, the weather information of the representative city at the time of traveling in the estimation target section is extracted from the weather information database (step S705). Note that the weather information database may be stored in the navigation device 300, or may be received in the database server or the like via the communication I / F 315.

The navigation device 300 uses the weather information extracted in step S705 to calculate a correction value by the various methods described above (step S706), and corrects the fuel consumption (estimated fuel consumption) estimated in step S702 ( Step S707). Then, the navigation device 300 displays the corrected estimated fuel consumption amount on the display 313 (step S708), and ends the processing according to this flowchart.

Next, 2) a case where fuel consumption is estimated at the time of route search and correction is continuously performed after the start of traveling will be described. This pattern is a method for continuously acquiring weather information even after the start of running and correcting the estimated fuel consumption when the fuel consumption in a predetermined section is estimated using, for example, the above equation (1). . The weather situation changes every moment, and it is possible to estimate the fuel consumption more accurately by performing correction using the latest weather information.

FIG. 8 is a flowchart showing another procedure for correcting the estimated fuel consumption amount by the navigation device. In the flowchart of FIG. 8, the navigation apparatus 300 first waits until a section (estimation target section) for estimating fuel consumption is designated (step S801: No loop).

When the estimation target section is designated (step S801: Yes), the navigation apparatus 300 estimates the fuel consumption amount in the estimation target section (step S802). Next, the navigation apparatus 300 extracts the representative city closest to each point of the estimation target section (step S803), and acquires the predicted passage time when traveling in the estimation target section (step S804).

Next, the navigation apparatus 300 receives an actual measured value of weather information in the representative city and a predicted value of weather information at the predicted passage time via the communication I / F 315 (step S805). The navigation apparatus 300 calculates a correction value by the various methods described above (step S806), corrects the fuel consumption amount (estimated fuel consumption amount) estimated in step S802 (step S807), and calculates the corrected estimated fuel consumption amount. The information is displayed on the display 313 (step S808). Until the traveling of the estimation target section ends (step S809: No), the navigation device 300 returns to step S804, and continues to acquire weather information and correct the estimated fuel consumption.

Then, when the travel in the estimation target section ends (step S809: Yes), the processing according to this flowchart ends. In step S809: No, the reason for returning to step S804 is that the estimated passage time may change due to various factors even after the start of traveling, and weather information is acquired in consideration of this change. .

Next, 3) A case where fuel consumption is estimated and corrected while driving will be described. As described above, the navigation device 300 acquires the acceleration information and the speed information of the vehicle in real time when the vehicle starts to travel, and uses the above equation (2) to reflect the actual driving state. Can be calculated.

Thus, even when the fuel consumption is estimated during actual traveling, the above-described correction method can be applied. FIG. 9 is a flowchart showing another procedure for correcting the estimated fuel consumption by the navigation device. In the flowchart of FIG. 9, the navigation device 300 first waits until the vehicle starts to travel (step S901: No loop). When the vehicle starts traveling (step S901: Yes), the vehicle speed information and Acceleration information is acquired (step S902), and fuel consumption is estimated using speed information and acceleration information (step S903).

Further, the navigation device 300 acquires the current position information of the vehicle (step S904), and extracts the representative city closest to the current location (step S905). And the navigation apparatus 300 acquires the weather information of the representative city at the present time (step S906). The weather information acquired in step S906 may be recorded in a weather information database, or may be an actual measurement value of weather information in a representative city.

The navigation device 300 calculates a correction value using the weather information acquired in step S906 (step S907), corrects the fuel consumption (estimated fuel consumption) estimated in step S903 (step S908), and corrects it. The estimated fuel consumption is displayed on the display 313 (step S909). Until the vehicle finishes traveling (step S910: No), the navigation apparatus 300 returns to step S902 and continues the estimation and correction of the fuel consumption. And if a vehicle complete | finishes driving | running | working (step S910: Yes), the process by this flowchart will be complete | finished.

Note that the fuel consumption correction process described above may be performed by an information processing apparatus other than the navigation apparatus 300. For example, necessary information (vehicle speed, acceleration, etc.) may be transmitted to the server or the like via the communication I / F 315, correction processing may be performed on the server, and the result may be returned to the navigation device 300.

As described above, according to the navigation device 300 according to the embodiment, the estimated fuel consumption amount is corrected using the weather information. Thereby, the fuel consumption can be estimated in consideration of the influence of the weather, and the prediction accuracy of the fuel consumption can be improved. Further, according to the navigation device 300, correction is performed in consideration of various weather factors such as temperature, atmospheric pressure, humidity, wind speed, wind direction, and precipitation, so that the error between the estimated fuel consumption and the actual fuel consumption can be further reduced. can do.

Further, if the navigation apparatus 300 acquires weather information from a database that records past weather information in a representative city, the above-described correction can be performed by incorporating the database into a conventional navigation apparatus. For this reason, for example, even in a navigation device that does not have a communication function, correction in consideration of weather information can be performed, and the estimation accuracy of fuel consumption can be improved at low cost.

In addition, if the navigation apparatus 300 acquires weather information via a network, it is possible to obtain measured values of weather information in real time, and to improve the estimation accuracy of fuel consumption. In addition, if the navigation apparatus 300 includes a measuring device that measures weather information, and the correction is performed using the weather information measured by the measuring device, the measurement point of the weather information matches the estimation target section. The weather information closest to the actual weather situation can be obtained, and the estimation accuracy of the fuel consumption can be further improved.

The fuel consumption estimation method described in the present embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program is recorded on a computer-readable recording medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. The program may be a transmission medium that can be distributed via a network such as the Internet.

DESCRIPTION OF SYMBOLS 100 Fuel consumption estimation apparatus 101 Estimation part 102 Route setting part 103 Acquisition part 104 Correction | amendment part

Claims

Estimating means for estimating the fuel consumption of the vehicle at a predetermined point;
Obtaining means for obtaining weather information of the predetermined point;
Correction means for correcting the fuel consumption estimated by the estimation means based on the weather information acquired by the acquisition means;
A fuel consumption estimation device comprising:
2. The fuel consumption estimation apparatus according to claim 1, wherein the estimation means estimates the fuel consumption at the predetermined point when the vehicle travels at the predetermined point.
It further comprises route setting means for setting a route to the destination point,
The estimation means estimates the fuel consumption of the vehicle in a predetermined section on the route including the predetermined point before the vehicle starts traveling on the route,
The fuel consumption estimation apparatus according to claim 1, wherein the acquisition unit acquires weather information in the predetermined section.
The acquisition means acquires temperature information at the predetermined point,
The fuel consumption estimation apparatus according to claim 1, wherein the correction unit corrects the fuel consumption estimated by the estimation unit using the temperature information.
The correction means reduces the value of the fuel consumption estimated by the estimation means when the temperature at the predetermined point is higher than a predetermined reference temperature, and the temperature at the predetermined point is the reference temperature. The fuel consumption estimation apparatus according to claim 4, wherein when the value is lower than the value, the value of the fuel consumption estimated by the estimation unit is increased.
The acquisition means acquires the temperature information at a temperature measurement point in the vicinity of the predetermined point,
5. The fuel consumption estimation apparatus according to claim 4, wherein the correction unit estimates temperature information at the predetermined point based on the temperature information at the temperature measurement point, and uses the temperature information for correcting the fuel consumption.
The fuel consumption estimation apparatus according to claim 6, wherein the correction means estimates temperature information at the predetermined point based on a difference between an altitude at the temperature measurement point and an altitude at the predetermined point.
The acquisition means acquires atmospheric pressure information of the predetermined point,
The fuel consumption estimation apparatus according to claim 1, wherein the correction unit corrects the fuel consumption amount using the atmospheric pressure information.
The correction means reduces the value of the fuel consumption estimated by the estimation means when the atmospheric pressure at the predetermined point is higher than a predetermined reference atmospheric pressure, and the atmospheric pressure at the predetermined point becomes the reference atmospheric pressure. The fuel consumption estimation apparatus according to claim 8, wherein when the value is lower, the value of the fuel consumption estimated by the estimation unit is increased.
The acquisition means acquires the atmospheric pressure information at an atmospheric pressure measurement point in the vicinity of the predetermined point,
9. The fuel consumption estimation apparatus according to claim 8, wherein the correction means estimates the atmospheric pressure at the predetermined point based on the atmospheric pressure information at the atmospheric pressure measurement point, and uses it for correcting the fuel consumption.
11. The fuel consumption estimation apparatus according to claim 10, wherein the correction means estimates the atmospheric pressure at the predetermined point based on a difference between an altitude at the atmospheric pressure measurement point and an altitude at the predetermined point.
The acquisition means acquires temperature information and humidity information of the predetermined point,
The fuel consumption estimation apparatus according to claim 1, wherein the correction unit corrects the fuel consumption amount using the temperature information and the humidity information.
The correction means increases the value of the fuel consumption estimated by the estimation means when the temperature and humidity at the predetermined point are higher than a predetermined reference temperature and reference humidity. The fuel consumption estimation apparatus according to claim 12.
The acquisition means acquires wind speed information and wind direction information of the predetermined point,
13. The fuel consumption estimation apparatus according to claim 12, wherein the correction unit corrects the fuel consumption amount using the wind speed information and the wind direction information.
The correction means calculates an air resistance received by the vehicle by the wind at the predetermined point based on the wind speed information and the wind direction information, and the estimation means estimates the higher the air resistance received by the vehicle. The fuel consumption estimation apparatus according to claim 14, wherein a value of the fuel consumption is increased.
The acquisition means acquires precipitation information of the predetermined point,
The fuel consumption estimation apparatus according to claim 12, wherein the correction unit corrects the fuel consumption amount using the precipitation information.
The said correction | amendment means enlarges the value of the said fuel consumption estimated by the said estimation means, when the precipitation of the said predetermined point is larger than the predetermined reference amount, The fuel consumption amount estimated by the said estimation means is enlarged. The fuel consumption estimation device described.
It has a database that records the past weather information at representative points,
The fuel consumption estimation apparatus according to claim 1, wherein the acquisition unit reads the weather information at the representative point corresponding to the predetermined point from the database.
An estimation process for estimating the fuel consumption of the vehicle at a predetermined point;
An acquisition step of acquiring weather information of the predetermined point;
A correction step of correcting the fuel consumption estimated in the estimation step based on the weather information acquired in the acquisition step;
The fuel consumption estimation method characterized by including.
A fuel consumption estimation program that causes a computer to execute the fuel consumption estimation method according to claim 19.
A computer-readable recording medium in which the fuel consumption estimation program according to claim 20 is recorded.