JP4884430B2 - Car navigation system - Google Patents

Description

  The present invention relates to an in-vehicle navigation device having a route search function for searching for a route with a minimum amount of fuel consumption from a current location to a destination.

  2. Description of the Related Art Car-mounted navigation devices that search for a travel route from a current location to a destination before leaving and guide the travel route to a driver by voice guidance or screen display while traveling to the destination are widely used.

  When searching for a route to a destination using these in-vehicle navigation devices, methods such as route search giving priority to travel distance (shortest distance search) and route search giving priority to travel time (shortest time search) are generally used. Is.

  Patent Document 1 listed below proposes an in-vehicle navigation device that searches for a route that requires the least amount of fuel consumption by using fuel consumption information corresponding to a moving speed.

JP 2005-172582 A

  According to the technology of Patent Document 1, by referring to the association data of the vehicle speed and fuel consumption (fuel consumption rate) obtained from the fuel consumption sensor based on the average vehicle speed obtained by dividing the link length in the database by the travel time, A method of calculating the amount of fuel consumed in the link section is used. However, in the technique of Patent Document 1, the fuel consumption calculated from the average vehicle speed is approximately a result of cruise driving, and is repeatedly repeated under normal driving, and when starting or accelerating to consume more fuel. No consideration is given to the driving mode. In other words, for example, when the vehicle travels at a constant speed of 40 km / h, and when the average vehicle speed is 40 km / h as a result of repeated acceleration / deceleration, the latter is used even if the average vehicle speed is the same. As you can see from the fact that a lot of fuel is consumed to accelerate, even if the fuel consumption is calculated simply by using the average vehicle speed of the link section, the result is far from the fuel consumption when actually driving. End up.

The present invention has been made to solve the above-described problem, and relates to a route search function for searching a route with the minimum fuel consumption to the destination, and in particular, by considering the fuel consumption in an extremely low speed state . Another object of the present invention is to provide an in-vehicle navigation device capable of calculating a more accurate fuel consumption.

The present invention is based on travel speed-fuel consumption rate association data stored in information recording means based on travel speed obtained from distance and travel time of each ring or node on the route of a map database storing data required for route search. A first predicted fuel amount calculating means for obtaining a fuel consumption rate and multiplying by the distance to obtain a first predicted fuel amount at each link or node; In the in-vehicle navigation device provided with navigation means for searching for at least one route having a small total predicted fuel quantity to the destination using these as predicted fuel quantities, the information recording means is configured to consume fuel by idling per unit time A unit idle fuel amount, which is a quantity, is further stored, and travel time passing through the link or node is set as idle time The second estimated fuel amount in the idling state of each link or node when the idling state is assumed during the travel time passing through the link or node is calculated from the idle time and the unit idle fuel amount. And a second predictive fuel amount calculating means, wherein the navigation means includes a switching means for switching the first and second predictive fuel amounts according to a travel speed, wherein the travel speed is a predetermined speed threshold value. In the vehicle-mounted navigation device , the second predicted fuel amount obtained by the second predicted fuel amount calculating means is used as the predicted fuel amount when passing through the link or node .

According to the present invention, it is possible to provide an in-vehicle navigation device capable of calculating a more accurate fuel consumption amount by taking into consideration the fuel consumption amount in an extremely low speed state .

Embodiment 1 FIG.
FIG. 1 is a diagram showing the configuration of an in-vehicle navigation device according to the present invention. In FIG. 1, an operation unit 1 is a switch for a driver to operate an in-vehicle navigation device. The map database 2 stores data necessary for route search such as map information data. The GPS receiver 3 receives radio waves for positioning from GPS (Global Positioning System) satellites. The VICS information receiver 4 is for transmitting and receiving VICS (Vehicle Information and Communication System) information. The VICS information receiver 4 is an optical beacon, a radio wave beacon, an FM multiple receiving antenna, and a function (wireless communication) capable of supporting a VICS information providing service. Equivalent to the Internet function).

  The calculation unit 5 performs a search process for a route with a small amount of fuel consumption from the current location to the destination (including navigation means). The display unit 6 displays a route to the destination searched by the calculation unit 5. The voice output unit 7 informs the traveling direction by voice when traveling along the route searched by the calculation unit 5. The vehicle information input / output unit 8 is connected to the vehicle via a communication line or the like (not shown), and receives vehicle information such as the vehicle speed, fuel consumption, and travel distance. The information recording unit (information recording means) 9 calculates the calculation unit 5 by associating the traveling vehicle speed with the actually consumed fuel amount based on the vehicle information obtained by the vehicle information input / output unit 8, for example. Various data necessary for navigation are recorded and stored, including travel speed-fuel consumption rate association data as shown in FIG. 5 to be described later of the vehicle on which the in-vehicle navigation device is mounted.

  FIG. 2 shows an operation flowchart of processing executed by the arithmetic unit 5, and the operation will be described in accordance with this flowchart. First, the current position of the host vehicle is acquired via the GPS receiver 3 (step S1). Next, the destination is set (step S2). At that time, in addition to the method of directly selecting the destination by operating the operation unit 1 while viewing the map screen displayed on the display unit 6, the driver operates the operation unit 1 to display the destination address or A method of selecting a destination by inputting information such as a telephone number is also widely used. In addition, when there is a waypoint to stop by, it is possible to input a waypoint in addition to the destination.

  Subsequently, when the destination and the waypoint are determined, VICS information is acquired (step S3). The VICS information is the latest road traffic information of national highways and main roads sent from the VICS center (not shown) via the VICS information receiver 4 and the Internet, and information can be obtained constantly.

  Subsequently, a search process for a route with a small amount of fuel consumption to the destination described later is executed according to FIG. 3 (step S4). After the route search to the destination is completed, the entire contents of the searched route are displayed on the display unit 6 (step S5). At this time, there is a method of not only displaying only the route with the smallest fuel consumption but also displaying a plurality of routes with less fuel consumption. As a result, the driver can select an arbitrary route from a plurality of information, which increases convenience. When the driver finally selects a desired route by the operation of the operation unit 1 (step S6), the route guidance by the screen display of the display unit 6 and the voice from the audio output unit 7 is started (step S7).

  FIG. 3 shows an operation flowchart of processing executed in the route search in step S4 of FIG. The Dijkstra method is used for the route search method of the present invention. Dijkstra method is one of the algorithms in graph theory and is a typical method for solving the shortest path problem. This method searches for a route that minimizes the cost of passing from the current location to the destination. Incidentally, the passage cost in the present invention is calculated using the fuel consumption. Note that the Dijkstra method is widely known, and the details are omitted in this specification.

  When the route search in step S4 is executed, calculation of the fuel consumption amount when the link and the node pass is started (step S41). This process is repeatedly executed for all links and nodes until the destination is reached (step S42). When the destination is reached, in step S43, the estimated fuel amount corrected with the additional fuel amount obtained for each link or node as described later is integrated along the route to obtain the total predicted fuel amount. Start to take out. In that case, it takes out by tracing from the destination to the departure place. As described above, also from the viewpoint of allowing the driver to select an arbitrary route, it is desirable to pick out the top several routes with a small total predicted fuel amount. The extracted route is stored in the map database 2 or an attached memory (not shown) (S step 44). A link indicates a road on the route, and a node indicates an intersection, a corner, an interchange, a gate, and the like.

  Next, the link cost and node cost calculation method executed in step S41 will be described. FIG. 4 is a functional block diagram for explaining the cost calculation method in this embodiment. The travel speed calculation unit 10, the multiplication unit 12, and the addition unit 13 which is an addition unit are part of the navigation unit, and the number-of-starts estimation unit 14 and the multiplication unit 16 form a starting additional fuel amount calculation unit, which are calculated. It consists of part 5. The travel speed-fuel consumption rate association data 9 a and the unit start additional fuel amount 9 b are stored in the information recording unit 9.

  Hereinafter, link cost calculation will be described. In addition to the data used for map drawing, the map database 2 stores data used for route calculation and route guidance, and the route calculation data stores data associated with all route links and nodes. Has been.

  As for the navigation means of the calculation unit 5, first, the travel speed calculation unit 10 refers to the link distance information and the travel time information in the map database 2. Then, the travel speed is obtained by dividing the referenced distance by the travel time. Here, if real-time link travel time information can be obtained from the VICS information receiver 4, the travel speed can be obtained with higher accuracy by using it instead of the travel time. Furthermore, when traffic congestion information (information classified as traffic jam / congestion / smooth) is obtained from the VICS information receiver 4, the travel speed is roughly determined from the traffic congestion degree and the road type, so this speed information is also used. You may do it.

  Subsequently, the fuel consumption rate when traveling at the travel speed is derived from the travel speed-fuel consumption rate association data 9a indicating the relationship between the own vehicle speed and the actual amount of actual fuel consumed. FIG. 5 shows an example in which travel speed-fuel consumption rate association data is graphed. The horizontal axis shows the travel speed (km / h), which is the speed of the vehicle at the time of cruising, and the vertical axis shows the fuel consumption rate (cc / km) when traveling at the travel speed. For example, when cruising at a speed of 30 km / h, the fuel consumption rate is about 70 cc / km.

  Although FIG. 5 is a simplified graph, the fuel consumption rate usually varies greatly even at the same traveling speed (travel speed) due to the driving method of the driver and the difference in traffic flow. It can happen. Therefore, in this case, the relational result shown in FIG. 5 can be obtained by obtaining an approximate value.

  In the in-vehicle navigation device, since it is considered that the conditions such as the displacement of the vehicle to be installed and the vehicle weight are indefinite, the vehicle speed, fuel consumption amount, Although it is necessary to collect the travel distance, if the mounted vehicle is fixed and the characteristics of fuel consumption are known in advance, the travel speed-fuel consumption rate association data 9a is stored in advance. Thus, the vehicle information input / output unit 8 can be omitted. Subsequently, the multiplication unit 12 multiplies the fuel consumption rate (cc / km) obtained previously and the link distance (km). Thus, the predicted fuel amount (cc) when traveling the distance of the link can be obtained.

  On the other hand, the number-of-starts estimation unit 14 estimates the number of starts at the time of passing through the link section based on traffic jam information (traffic jam / congestion / smooth) received via the VICS information receiver 4. For example, in VICS traffic information (traffic information), when a general road is congested, the travel speed of the link is defined as 10 km / h or less. In this case, it can be easily estimated that the stop and the start are repeated. In that case, the number-of-starts estimation unit 14 estimates the number of starts per km, for example, as 15. Note that the vehicle speed (travel speed) specified for each degree of congestion differs depending on the road type, and therefore it is necessary to estimate the number of departures according to each. Therefore, for example, a table (traffic information-fuel consumption increase / decrease travel mode count table) indicating the number of starts per unit distance for each road type for each congestion level is stored in the information recording unit 9 in advance, and the traffic congestion information of VICS is stored. The number of departures is estimated from the table.

  Further, the accuracy of the number of times of starting can be improved by collecting statistics by a running test, an actual environment survey or the like. Furthermore, since the VICS information includes traffic obstacle information and traffic regulation information in addition to traffic jam information, it is more desirable to estimate the number of departures by taking these information into account. By the way, VICS information does not cover all roads nationwide. Therefore, when predicting the number of departures on links where VICS information cannot be obtained, for example, field surveys such as 2 times per link, 2 times per km, 1 time per node, 1 time when turning left and right, etc. It is possible to cope with this problem by previously obtaining and storing and using data based on statistics.

  The additional fuel amount 9b at the time of unit start is the amount of fuel consumed when starting the vehicle stored in the information recording unit 9. This is the case, for example, when an extra 5 cc of fuel is consumed at one start. The multiplying unit 16 can determine the additional fuel amount for start related to the start in the link section by multiplying the start number estimated by the start number estimating unit 14 by the unit start additional fuel amount 9b at the start. Finally, the adding unit 13 adds the additional fuel amount for starting to the predicted fuel amount. As a result, it is possible to more accurately determine the amount of fuel consumed when passing through the link or node, taking into account the increase in fuel when the vehicle starts. Therefore, by using the link cost or node cost calculation method described in the first embodiment, the fuel consumption amount at the time of passing through the link or node is more accurately obtained by adding the fuel increase amount at the start to the predicted fuel amount. Therefore, it is possible to improve the accuracy of searching for a route that minimizes fuel consumption.

Embodiment 2. FIG.
In the first embodiment, a method for more accurately obtaining the fuel consumption amount at the time of starting or passing through a link or node, which is one of the traveling modes that consume a large amount of fuel, has been described. In the second embodiment, a method for more accurately obtaining the fuel consumption amount during acceleration from cruise traveling, which is another traveling mode that consumes much fuel, will be described. In the processing steps executed by the calculation unit 5, the portions other than the internal processing in step S41 in FIG. 3 are basically the same as those described in the first embodiment, and description thereof is omitted.

  FIG. 6 is a functional block diagram for explaining a link (node) cost calculation method according to the second embodiment corresponding to FIG. The processing up to the travel speed calculation unit 10 that calculates the predicted fuel amount, the travel speed-fuel consumption rate association data 9a, and the multiplication unit 12 using the distance data and travel time data of the map database 2 has been described in the first embodiment. Street.

  Based on the traffic jam information acquired from the VICS information receiver 4, the acceleration frequency estimation unit 17 estimates the acceleration frequency when passing through the link section. For example, the VICS traffic information stipulates that when a highway is congested, the travel speed of the link is 40 km / h or less. In that case, in the acceleration frequency estimation part 17, the acceleration frequency per km is estimated as 20 times, for example. In addition, since the vehicle speed prescribed | regulated according to the said traffic congestion degree changes also with road types, it is necessary to estimate the frequency | count of acceleration according to each. Therefore, for example, a table (traffic information-fuel consumption increase / decrease travel mode count table) indicating the number of accelerations per unit distance for each road type for each traffic congestion level is stored in advance in the information recording unit 9, and traffic congestion information of VICS is stored. , The number of accelerations is estimated from the table.

  In addition, the accuracy of the number of accelerations can be increased by taking statistics by running tests, actual environment surveys, or the like. Furthermore, since VICS information includes traffic fault information and traffic regulation information in addition to traffic jam information, it is more desirable to estimate the number of accelerations in consideration of such information. As in the first embodiment, when the number of accelerations is predicted using a link from which VICS information cannot be obtained, for example, the number of accelerations may be estimated for each speed according to the travel speed obtained by the travel speed calculation unit 10 Correspondence is also possible by using data from field surveys and statistics, such as 10 times per link, 5 times per km, 1 time per node, 2 times when turning left and right.

  The unit-accelerated additional fuel amount 9c is a fuel amount consumed when the vehicle stored in the information recording unit 9 is accelerated. FIG. 7 is a diagram showing the relationship of the additional fuel amount (additional fuel amount during unit acceleration) with respect to the speed increase amount during one acceleration. For example, an increase in the speed of 40 km / h during acceleration indicates that about 4 cc of fuel is consumed. The multiplying unit 16 can obtain the acceleration additional fuel amount related to the acceleration in the link section by multiplying the number of accelerations estimated by the acceleration number estimating unit 17 by the unit acceleration additional fuel amount 9c during acceleration. Finally, as in the first embodiment, the addition unit 13 adds the additional fuel amount for acceleration to the predicted fuel amount. As a result, it is possible to more accurately obtain the fuel consumption amount when passing through the link or the node in consideration of the fuel increase amount at the time of vehicle acceleration.

  Therefore, by using the link cost or node cost calculation method described in the second embodiment, the amount of fuel increase in acceleration from cruise traveling is added to the predicted fuel amount, so that the fuel consumption amount when passing through the link or node. Can be obtained more accurately, so that the search accuracy of the route with the minimum fuel consumption can be improved.

  The travel speed calculation unit 10, the multiplication unit 12, and the addition unit 13 as addition means are part of the navigation means, and the acceleration number estimation unit 17 and multiplication unit 16 form acceleration additional fuel amount calculation means. Is constituted by the arithmetic unit 5. The travel speed-fuel consumption rate association data 9 a and the unit-accelerated additional fuel amount 9 c are stored in the information recording unit 9.

Embodiment 3 FIG.
In the second embodiment, the method for more accurately obtaining the fuel consumption amount at the time of passing through the link or node at the time of acceleration, which is one of the traveling forms consuming a large amount of fuel, has been described. In the third embodiment, a method of obtaining the fuel consumption more accurately when the travel speed becomes extremely low will be described. Note that, in the processing steps executed by the arithmetic unit 5, the portions other than the internal processing in step S41 in FIG. 3 are basically the same as those already described in the first and second embodiments, and the description thereof is omitted.

  FIG. 8 is a functional block diagram for explaining a link (node) cost calculation method according to the third embodiment corresponding to FIG. Using the distance data and travel time data of the map database 2, the travel speed calculation unit 10 that calculates the first predicted fuel amount, the travel speed-fuel consumption rate association data 9 a, and the first predicted fuel amount of the multiplier 12 are obtained. The processing until the calculation is as described in the first embodiment.

  FIG. 9 shows travel speed-fuel consumption rate association data 9a for associating the own vehicle speed and the actual fuel amount described in the first embodiment. From the travel speed-fuel consumption rate association data 9a, it can be seen that a greater amount of fuel is consumed as the travel speed decreases during traveling of the vehicle. However, when the host vehicle travels at a very low speed (for example, 10 km / h or less), the driver particularly uses creep traveling to advance the vehicle in an idling state. Accordingly, when the travel speed is extremely low, if the value of the travel speed-fuel consumption rate association data 9a or an approximate value thereof is used, the predicted fuel amount is compared with the fuel amount actually consumed in creep travel. The fuel amount will be much larger.

  The idle time 9e passes through the link, which is one of the VICS information, assuming that it is idling during the travel time passing through the link, which is temporarily stored in the temporary storage unit (not shown) or the information recording unit 9. Link travel time (node travel time in case of node cost calculation). In the case of a link for which VICS information cannot be obtained, the travel time is referred to from the map database 2 and is set as the idle time. The unit idle fuel amount 9d is a fuel consumption amount per unit time during idling stored in the information recording unit 9. The multiplication unit 16 multiplies the idle time 9e, which is travel time, and the unit idle time fuel amount 9d to obtain a second predicted fuel amount.

  The navigation means includes a changeover switch 21 that is a switching means for outputting one result of the first predicted fuel amount from the multiplication unit 12 and the twenty-first predicted fuel amount from the multiplication unit 16. The changeover switch 21 is switched based on the travel speed obtained by the travel speed calculation unit 10. For example, when the speed is 10 km / h or more, the first predicted fuel amount is output, and when the speed is less than 10 km / h, the first switch is output. The predicted fuel amount of 2 is output. Accordingly, when the travel speed obtained is extremely low, it is determined that creep travel is frequently used, and the predicted fuel in the link is determined from the second predicted fuel amount based on the unit idle fuel amount 9d that is the fuel consumption amount during idling. Find the amount. On the other hand, when the travel speed is not extremely low, the predicted fuel is obtained from the first predicted fuel amount based on the travel speed-fuel consumption rate association data 9a.

  Therefore, if the vehicle is traveling at an extremely low speed such that the travel speed falls below a predetermined speed threshold, it can be determined that the vehicle is traveling in a state that is close to creep travel. Therefore, fuel consumption due to idling per unit time and travel Since the amount of fuel consumed when passing through a link or node can be obtained more accurately from time, the search accuracy for a route that minimizes fuel consumption can be improved.

  The travel speed calculation unit 10, the multiplication unit 12, and the changeover switch 21 that is a switching unit are part of the navigation unit, and the multiplication unit 16 forms a second predicted fuel amount calculation unit, and these are the calculation unit 5. Composed. The travel speed / fuel consumption rate association data 9a and the unit fuel amount 9d during idle time are stored in the information recording unit 9, and the idle time 9e is temporarily stored in the information recording unit 9.

  Needless to say, the present invention includes these possible combinations and the like regardless of the above embodiments.

  In particular, in the first and second embodiments, starting and accelerating are cited as examples of the fuel consumption increasing traveling mode, respectively, but other fuel consumption increasing traveling modes may be implemented. Parallel processing may be performed to obtain a composite additional fuel amount (total additional fuel amount). On the contrary, regarding the reduction of fuel consumption, in particular, the fuel consumption reduction traveling mode such as constant speed operation that occurs when traffic congestion information is smooth, the reduction fuel amount is similarly calculated from the cumulative number of occurrences and unit reduction fuel amount. It may be obtained and subtracted from the predicted fuel amount. Furthermore, the fuel consumption increase travel mode and the fuel consumption decrease travel mode may be processed in parallel to obtain the additional / reduced fuel amount.

  In summary, for each fuel consumption increase / decrease travel mode, a unit addition / decrease fuel amount and a traffic information-fuel consumption increase / decrease travel mode frequency table are stored in the information recording unit 9, for example, FIG. , The number-of-starts estimation unit 14 is used as a fuel consumption increase / decrease travel mode number estimation unit (means), and the number of occurrences is determined for each travel mode. And add / decrease fuel amount. In the case of only the increased running mode, the adding unit 13 adds the additional fuel amount to the predicted fuel amount. In the case of only the reduced travel mode, the addition unit 13 is used as a subtraction unit to subtract the reduction fuel amount from the predicted fuel amount.

  When the increase travel mode and the decrease travel mode are processed in parallel, the addition unit 13 performs addition / subtraction as an arithmetic unit to add an additional fuel amount to the predicted fuel amount and subtract a decrease fuel amount, respectively. Note that a new subtracting unit (not shown) is provided on the output side of the multiplying unit 16 to obtain an adjusted additional fuel amount by subtracting the reduced fuel amount from the additional fuel amount (if the reduced fuel amount is large, a negative value is obtained. This may be added to the predicted fuel amount by the adding unit 13. The fuel consumption increase / decrease travel mode number estimation unit and multiplication unit 16 corresponding to 14 in FIG. 4 constitute the fuel consumption increase / decrease travel mode addition / decrease fuel amount calculation means.

It is a figure which shows the structure of the vehicle-mounted navigation apparatus concerning this invention. It is an operation | movement flowchart of the process performed by the calculating part of FIG. 3 is an operation flowchart of processing executed in the route search in step S4 of FIG. 2. It is a functional block diagram for demonstrating the cost calculation method in Embodiment 1 of this invention. It is a figure which shows an example which graphed the travel speed-fuel consumption rate correlation data in Embodiment 1 of this invention. It is a functional block diagram for demonstrating the cost calculation method in Embodiment 2 of this invention. It is the figure which showed the relationship of the additional fuel amount (additional fuel amount at the time of unit acceleration) with respect to the speed increase amount at the time of one acceleration in Embodiment 2 of this invention. It is a functional block diagram for demonstrating the cost calculation method in Embodiment 3 of this invention. It is a figure which shows an example which plotted the travel speed-fuel consumption rate correlation data for demonstrating the fuel consumption rate at the time of creep driving | running | working in Embodiment 3 of this invention.

Explanation of symbols

  1 operation unit, 2 map database, 3 GPS receiver, 4 VICS information receiver, 5 calculation unit, 6 display unit, 7 audio output unit, 8 vehicle information input / output unit, 9 information recording unit, 9a travel speed-fuel consumption rate association Data, 9b additional fuel amount at unit start, 9c additional fuel amount at unit acceleration, 9d unit fuel amount at idling, 9e idle time, 10 travel speed calculation unit, 12 multiplication unit, 13 addition unit, 14 start number estimation unit, 16 Multiplication unit, 17 acceleration number estimation unit, 21 selector switch.

Claims (1)

Based on the travel speed obtained from the distance and travel time of each ring or node on the route of the map database storing the data required for the route search, the fuel consumption rate is calculated from the travel speed-fuel consumption rate association data stored in the information recording means. A first predicted fuel amount calculating means that obtains a first predicted fuel amount at each link or node by multiplying the distance and obtains the first predicted fuel amount at each link or node as the predicted fuel amount; In the vehicle-mounted navigation device provided with navigation means for searching for at least one route with a small total predicted fuel amount to the destination using these,
  The information recording means further stores a unit idle fuel amount that is fuel consumption by idling per unit time, and temporarily stores a travel time passing through the link or node as an idle time,
  Calculating a second predicted fuel amount in the idling state of each link or node when the idling state is assumed during the travel time passing through the link or node from the idle time and the unit idle fuel amount; Predicted fuel amount calculating means;
  Further comprising
  The navigation means includes switching means for switching the first and second predicted fuel amounts according to travel speed, and when the travel speed falls below a predetermined speed threshold, the second predicted fuel amount fueling means The in-vehicle navigation device characterized in that the second predicted fuel amount obtained by the step is used as a predicted fuel amount when passing through the link or node.

Images