JP7635701B2 - Navigation Device - Google Patents

Description

This disclosure relates to a navigation device.

A fuel cell (FC) is a power generation device that is composed of one unit cell (hereinafter sometimes referred to as a cell) or a fuel cell stack (hereinafter sometimes simply referred to as a stack) made up of multiple stacked unit cells, and produces electrical energy through an electrochemical reaction between a fuel gas such as hydrogen and an oxidant gas such as oxygen.
In the following, the fuel gas and the oxidant gas may be referred to simply as "reactant gas" or "gas" without any particular distinction. In addition, both a single cell and a fuel cell stack formed by stacking single cells may be referred to as a fuel cell.

2. Description of the Related Art Various studies have been conducted on devices mounted on fuel cell vehicles (FCEVs, hereinafter sometimes referred to as vehicles).
For example, Patent Document 1 discloses a fuel cell vehicle that is configured to identify hydrogen stations (ST) within a driving distance range, compare the driving distance with the distance to a destination, and change the route to a route that passes through the hydrogen ST if the distance to the destination is longer than the driving distance.

Patent document 2 discloses a route search device that estimates the remaining battery power upon arrival at a destination and determines the route that is closest to a specified amount of power as the recommended route.

JP 2021-110547 A International Publication No. 2013/172157

Although fuel cell vehicles can reach their destination, there is a risk that the hydrogen fuel will run out upon arrival at the destination, resulting in a shortage of hydrogen after arriving at the destination. With fuel cell vehicles, there are needs to save enough hydrogen to travel from the destination to the nearest hydrogen station, and needs to use fuel cell vehicles as generators at campsites, etc.
can.

This disclosure has been made in consideration of the above-mentioned circumstances, and its main objective is to provide a navigation device that can prevent the occurrence of a lack of hydrogen after arriving at a destination.

A navigation device according to the present disclosure is a navigation device that is mounted on a fuel cell vehicle having a fuel cell that uses hydrogen gas as a fuel gas, and that performs route guidance for the fuel cell vehicle,
An acquisition unit that acquires a current amount of hydrogen A and an amount of hydrogen consumption X that is expected to be consumed up to the destination;
an identification unit that identifies a first hydrogen station that is present in the vicinity of a route from a current location to the destination and a second hydrogen station that is closest to the destination;
A calculation unit that calculates an expected remaining amount of hydrogen B (B=A-X) upon arrival at the destination and a required amount of hydrogen C upon arrival at the destination;
A path setting unit,
The route setting unit is characterized in that when the estimated remaining hydrogen amount B is smaller than the required hydrogen amount C (B<C), the route setting unit changes the route from the current location to the destination to a route that passes through the first hydrogen station.

In the navigation device disclosed herein, the required amount of hydrogen C may be the minimum amount of hydrogen F required to reach the second hydrogen station from the destination.

In the navigation device of the present disclosure, the acquisition unit acquires a planned hydrogen usage amount D to be used at the destination,
The route setting unit may perform route search so as to leave a minimum required amount of hydrogen F for reaching the second hydrogen station from the destination and the planned amount of hydrogen usage D.

In the navigation device of the present disclosure, the planned hydrogen usage amount D may be a value that is statistically calculated from a user-input value or a destination attribute.

In the navigation device disclosed herein, when a specific location is set during destination setting, the route setting unit may issue a command to confirm whether or not hydrogen is required at the destination.

In the navigation device of the present disclosure, the route setting unit may issue an alarm if there is a risk that the amount of hydrogen F required to reach the second hydrogen station from the destination will fall below the minimum amount required during hydrogen use at the destination.

In the navigation device disclosed herein, when the planned hydrogen usage amount D is a value statistically calculated from the destination attributes, the acquisition unit may compare the amount of hydrogen actually consumed at the destination E with the planned hydrogen usage amount D to calculate an error, accumulate data on the error, and correct the planned hydrogen usage amount D in accordance with the error.

In the navigation device of the present disclosure, the route setting unit may select, in the route change, from among the two or more first hydrogen stations, a hydrogen station that minimizes the amount of hydrogen consumption Y that is expected to be consumed from the current location to the destination via the hydrogen station.

The navigation device disclosed herein can prevent the occurrence of a lack of hydrogen after arriving at a destination.

FIG. 1 is a flowchart showing an example of a procedure for a navigation device of the present disclosure to guide a route from a current location to a destination so as to leave a minimum amount of hydrogen necessary to reach the nearest hydrogen station upon arrival at the destination. FIG. 2 is a diagram showing an example of a case where the condition is satisfied without stopping at a hydrogen station, a case where the condition is not satisfied but a case where the condition is satisfied and a case where the condition is satisfied but a stop is made at the hydrogen station, and a case where the condition is satisfied but not. 3 is a flowchart showing an example of a procedure in which the navigation device of the present disclosure changes the route from the current location to the destination in accordance with the planned amount of hydrogen usage D to be used at the destination. First, the destination is input into the navigation device. Figure 4 is a diagram showing an example of a case in which a route is guided to satisfy the condition B ≥ F + D or B' ≥ F + D, where the condition is satisfied without stopping at a hydrogen ST, a case in which the condition is not satisfied but a case in which the route is guided to satisfy the condition without stopping at a hydrogen ST, and a case in which the condition is satisfied. FIG. 5 is a flowchart showing an example of guidance provided by the navigation device of the present disclosure when a destination has not been set.

A navigation device according to the present disclosure is a navigation device that is mounted on a fuel cell vehicle having a fuel cell that uses hydrogen gas as a fuel gas, and that performs route guidance for the fuel cell vehicle,
An acquisition unit that acquires a current amount of hydrogen A and an amount of hydrogen consumption X that is expected to be consumed up to the destination;
an identification unit that identifies a first hydrogen station that is present in the vicinity of a route from a current location to the destination and a second hydrogen station that is closest to the destination;
A calculation unit that calculates an expected remaining amount of hydrogen B (B=A-X) upon arrival at the destination and a required amount of hydrogen C upon arrival at the destination;
A path setting unit,
The route setting unit is characterized in that when the estimated remaining hydrogen amount B is smaller than the required hydrogen amount C (B<C), the route setting unit changes the route from the current location to the destination to a route that passes through the first hydrogen station.

The navigation device of the present disclosure searches for a route and hydrogen stations along the route, leaving at least the minimum amount of hydrogen F required to reach the nearest hydrogen ST (second hydrogen station) from the destination as the required amount of hydrogen C required upon arrival at the destination, and provides route guidance. Furthermore, if hydrogen can be used at the destination, the remaining amount of hydrogen is increased by the amount of hydrogen D planned to be used at the destination according to the intended use.
In the present disclosure, each of the values of the current amount of hydrogen A, the estimated remaining amount of hydrogen B, the estimated remaining amount of hydrogen B' when reaching the destination from the candidate hydrogen ST (first hydrogen station), the amount of hydrogen C required when reaching the destination, the planned amount of hydrogen used at the destination D, the amount of hydrogen actually consumed E at the destination, the amount of hydrogen required F from the destination to the nearest hydrogen ST to the destination, the amount of hydrogen G required from the current location to the nearest hydrogen ST, the amount of hydrogen consumed X expected to be consumed to the destination, the estimated amount of hydrogen consumed Y from the current location to the destination via the candidate hydrogen ST, and the estimated amount of hydrogen consumed Z from the candidate hydrogen ST to the destination may be expressed as a percentage of hydrogen (%) or as mass (kg).

The navigation device disclosed herein is a navigation device that is mounted on a fuel cell vehicle having a fuel cell that uses hydrogen gas as fuel gas, and provides route guidance for the fuel cell vehicle.

A fuel cell vehicle has a fuel cell as a power source for the traction motor.
The fuel cell may be a single cell, which is a power generating element capable of generating power by itself, or may be a fuel cell stack, which is a stack of a plurality of single cells.
The number of stacked unit cells is not particularly limited, and may be, for example, from 2 to several hundred.
In this embodiment, the fuel cell is a solid polymer fuel cell, and hydrogen gas is used as the fuel gas and air is used as the oxidizing gas.
In addition to a fuel cell, a fuel cell vehicle is equipped with a hydrogen gas system that supplies hydrogen gas to the fuel cell, including a hydrogen tank for storing hydrogen gas, a hydrogen gas supply line for supplying hydrogen gas from the hydrogen tank to the fuel cell, a main stop valve, a pressure sensor, etc.

The navigation device disclosed herein has an acquisition unit, a determination unit, a calculation unit, and a route setting unit, and typically includes a display unit, etc.

The acquisition unit, the identification unit, the calculation unit, and the route setting unit may be controlled by a control unit that controls the entire navigation device.
The control unit is configured by a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a GNSS function unit. The CPU reads out a control program stored in the ROM, expands it into the RAM, and executes it to function as an acquisition unit, a specification unit, a calculation unit, and a route setting unit.

In addition to the control program described above, the ROM also stores map information in advance. This map information includes information such as the location and size of roads and intersections, as well as information such as the size and type of buildings. Therefore, information about hydrogen stations is also included in the map information. Information about hydrogen stations included in the map information includes, for example, the name of each hydrogen station, i.e., "first hydrogen station" and "second hydrogen station," as well as the location of each hydrogen station, and information about the outline and size of the site and buildings.

The GNSS function unit identifies the current location (latitude and longitude) of the fuel cell vehicle using the Global Navigation Satellite System (GNSS).
As the GNSS, any type of GNSS may be used, such as GPS (Global Positioning System), Galileo, or QZSS.

The acquisition unit acquires the current hydrogen amount A and the hydrogen consumption amount X that is expected to be consumed up to the destination.
The acquisition unit may use the pressure in the hydrogen tank detected by a pressure sensor to determine the current hydrogen amount A. The current hydrogen amount A may be determined by, for example, storing in advance in a ROM a map that correlates the pressure in the hydrogen tank with the remaining amount of hydrogen (current hydrogen amount A) and referring to the map. Alternatively, for example, an arithmetic expression that expresses the relationship between pressure and remaining amount of hydrogen may be determined in advance, and the remaining amount of hydrogen may be calculated by applying the pressure value to the arithmetic expression.
The acquisition unit may acquire the hydrogen consumption amount X from the average vehicle speed and the amount of hydrogen consumed from when the fuel cell vehicle was started to the present time.

The identification unit identifies a first hydrogen station located in the vicinity of a route from a current location to a destination, and a second hydrogen station that is closest to the destination.
The first hydrogen station may be a hydrogen station located on the shortest route from the current location to the destination, or a nearest hydrogen station located in the vicinity of the shortest route.

The calculation unit calculates an expected remaining amount of hydrogen B (B=AX) upon arrival at the destination, and an amount of hydrogen C required upon arrival at the destination.
The required amount of hydrogen C may be the minimum amount of hydrogen F required to reach the second hydrogen station from the destination. The minimum amount of hydrogen F required may include a margin so that the remaining amount of hydrogen does not become zero when the vehicle reaches the second hydrogen station.
When searching for a route that passes through a first hydrogen station, the calculation unit may calculate the estimated hydrogen consumption Y from the current location to the destination via the candidate hydrogen station ST (first hydrogen station), calculate the estimated hydrogen consumption Z from the candidate hydrogen station ST to the destination, and calculate the estimated remaining hydrogen amount B' upon reaching the destination from the candidate hydrogen station ST from Equation 1 (B'=100-Z), assuming, for example, that hydrogen is replenished at the candidate hydrogen station ST until the tank is filled to 100. In Equation 1, 100 is a value assuming that hydrogen is replenished at the candidate hydrogen station ST until the tank is filled to 100, and therefore may be changed as appropriate depending on the amount of hydrogen to be replenished at the candidate hydrogen station ST.

The route setting unit sets a target route for the fuel cell vehicle. The target route means a route that is set as a route that the fuel cell vehicle will take to reach the destination. In this embodiment, the route setting unit displays a menu screen for route setting on the display unit, and when the user sets the destination on the menu screen, the route setting unit searches for and sets a route from the current location of the fuel cell vehicle to the destination according to a predetermined algorithm. In this embodiment, the above-mentioned "predetermined algorithm" may be an algorithm for finding the shortest distance, such as Dijkstra's algorithm. Note that, as a search algorithm for the target route by the route setting unit, instead of or in addition to the algorithm for finding the shortest distance, other types of algorithms may be used, such as an algorithm for finding a route that takes into account the driving time zone, toll roads, etc. in the shortest time, or an algorithm for finding the lowest cost route.
When the estimated remaining amount B of hydrogen is smaller than the required amount C of hydrogen (B<C), the route setting unit changes the route from the current location to the destination to a route that passes through the first hydrogen station.
When changing the route, the route setting unit may select, from among two or more first hydrogen stations, the hydrogen station that provides the smallest amount of hydrogen consumption Y that is expected to be consumed from the current location to the destination via the hydrogen station.
If the destination cannot be reached even by passing through the first hydrogen station, the route setting unit may search for a route that stops at two or more hydrogen stations, or may notify the user that the destination cannot be reached. The notification may be displayed on a screen serving as a display unit.

The display unit displays map images as well as various menu screens, messages, alerts, etc. The display unit may be configured as a touch panel and accepts operations by the user.

First Embodiment
FIG. 1 is a flowchart showing an example of a procedure for a navigation device of the present disclosure to guide a route from a current location to a destination so as to leave a minimum amount of hydrogen necessary to reach the nearest hydrogen station upon reaching the destination.
First, the destination is input into the navigation device.
Thereafter, the acquisition unit acquires the current hydrogen amount A and the hydrogen consumption amount X that is expected to be consumed up to the destination.
The calculation unit calculates the expected remaining hydrogen amount B (B=A-X) upon arrival at the destination, and the required hydrogen amount C upon arrival at the destination. The required hydrogen amount C upon arrival at the destination may be calculated as the minimum required hydrogen amount F to reach the second hydrogen station from the destination, or may include the planned hydrogen usage amount D to be used at the destination, which will be described later.
If the estimated remaining hydrogen amount B is equal to or greater than the required hydrogen amount C upon arrival at the destination (B≧C), the route setting unit sets a route that does not guide the vehicle to a hydrogen ST.
On the other hand, when the estimated hydrogen remaining amount B is smaller than the required hydrogen amount C required when arriving at the destination (B<C), the identifying unit picks out hydrogen ST candidates that are reachable from the current location and exist in the vicinity of the route from the current location to the destination. For example, the current hydrogen amount A can be compared with the hydrogen amount G required from the current location to the nearest hydrogen ST to determine whether the destination is reachable from the current location. The calculation unit calculates the estimated hydrogen consumption amount Y from the current location to the destination via the candidate hydrogen ST, calculates the estimated hydrogen consumption amount Z from the candidate hydrogen ST to the destination, and calculates the estimated hydrogen remaining amount B' when arriving at the destination from the candidate hydrogen ST using formula 1 (B'=100-Z). In formula 1, 100 is used on the assumption that hydrogen will be filled up to the full at the candidate hydrogen ST to be visited, but it may be variable.
The route setting unit then searches whether there is a hydrogen ST where B'≧C, and if not, notifies the user that it is not possible to reach the destination in a single stop at the hydrogen ST and terminates the search, or it may search for a route that includes stops at two or more hydrogen STs.
On the other hand, if there is a hydrogen station for which B'≧C, the route setting unit selects the hydrogen station for which Y is the smallest from among the multiple hydrogen station candidates, and determines it as the first hydrogen station.
Then, the route from the current location to the destination is changed to a route that passes through the first hydrogen station, and the route is determined as the guide route.

Figure 2 is a diagram showing an example of a case in which a route is provided that satisfies the condition B≧C or B'≧C, where the condition is met without stopping at a hydrogen station, a case in which the condition is not met but a stop is made at the station, and a case in which the condition is met.
As a premise, the hydrogen tank is full at 100 at the current location and when stopping at the hydrogen ST, and a minimum of 30 hydrogen is left as the minimum amount of hydrogen F required to reach the second hydrogen station from the destination, and the amount of hydrogen C (C = F) required when reaching the destination is left.
(i) Route 1 in Case 1 is a case in which condition B≧C is satisfied without hydrogen refueling, (ii) Route 1 in Case 2 is a case in which condition B≧C is not satisfied without hydrogen refueling, Route 2 is a case in which hydrogen is refueled but condition B'≧C is not satisfied (a case in which hydrogen is wasted due to a nearby hydrogen ST), Route 3 is the first example of a case in which condition B'≧C is satisfied with hydrogen refueling, and Route 4 is the second example of a case in which condition B'≧C is satisfied with hydrogen refueling.
When stopping at a hydrogen ST, (ii) routes 3 and 4 in case 2 both satisfy the conditions, but route 3 may be selected since it has a shorter total distance from the departure point to the destination via the hydrogen ST.

Second Embodiment
The acquisition unit may acquire a planned hydrogen usage amount D to be used at the destination.
The route setting unit may perform route search so as to leave the minimum amount of hydrogen F required to reach the second hydrogen station from the destination and the planned amount of hydrogen D to be used at the destination as the amount of hydrogen C required upon arrival at the destination. In other words, in this case, the amount of hydrogen C required upon arrival at the destination includes the minimum amount of hydrogen F required to reach the second hydrogen station from the destination and the planned amount of hydrogen D to be used at the destination (C=F+D).
For example, when the destination is a specific location such as a campsite, the recommended route may be changed according to the planned amount D of hydrogen to be used at the destination.
In the example shown in Fig. 1, the amount of hydrogen remaining when the vehicle reaches the destination is set to "the amount that can be filled with hydrogen at the nearest hydrogen station at the very least", but depending on the purpose of use at the destination, there may be a need to increase the remaining amount (e.g., the destination is a campsite and the driver wishes to refuel at the site). Therefore, the guided route is changed depending on the planned amount D of hydrogen to be used at the destination.

The planned amount of hydrogen used at the destination D may be a user-entered value or a value statistically calculated from the destination attributes.
If the planned amount of hydrogen usage D to be used at the destination is a value calculated statistically from destination attributes, the acquisition unit may compare the amount of hydrogen consumption E actually consumed at the destination with the planned amount of hydrogen usage D to be used at the destination to calculate an error, accumulate data on the error, and correct the planned amount of hydrogen usage D in accordance with the error.
The data collected by the vehicle may be transmitted to an information center.
Data transmission may be performed using any type of wireless communication such as mobile communication provided by a telecommunications carrier, such as 4G (4th Generation) communication, LTE (Long Time Evolution) communication, or 5G (5th Generation) communication, or a wireless LAN (Local Area Network).

When a specific location is set when setting the destination, the route setting unit may issue a command to confirm whether or not hydrogen will be used at the destination in order to prompt the user to input the planned amount D of hydrogen to be used at the destination. The command may be displayed on a screen that is a display unit.

The route setting unit may sound an alarm if, during the use of hydrogen at the destination, there is a risk that the amount of hydrogen will fall below the minimum amount F required to reach the second hydrogen station from the destination. The alarm may be displayed on a screen that is the display unit, or an alarm sound may be emitted. The point at which there is a risk that the amount of hydrogen will fall below the minimum amount F required to reach the second hydrogen station from the destination may be when the remaining amount of hydrogen reaches the minimum amount of hydrogen F required to reach the second hydrogen station from the destination, or when the remaining amount of hydrogen reaches a predetermined amount before reaching the minimum amount of hydrogen F required to reach the second hydrogen station from the destination.

FIG. 3 is a flowchart showing an example of a procedure in which the navigation device of the present disclosure changes the route from the current location to the destination in accordance with the planned amount D of hydrogen to be used at the destination.
First, the destination is input into the navigation device.
Thereafter, the acquisition unit acquires the current hydrogen amount A and the hydrogen consumption amount X that is expected to be consumed up to the destination.
The calculation unit calculates the expected remaining amount of hydrogen B (B=AX) upon arrival at the destination, and the minimum amount of hydrogen F required to reach the second hydrogen station from the destination.
The acquisition unit acquires the planned amount of hydrogen usage D to be used at the destination (the planned amount of hydrogen usage D may be determined by the system from the destination attributes, or may be determined by the user's will).
If the estimated remaining hydrogen amount B is equal to or greater than the minimum required hydrogen amount F to reach the second hydrogen station from the destination plus the planned hydrogen usage amount D (B≧F+D), the route setting unit sets a route that does not guide the vehicle to the hydrogen ST.
On the other hand, if the estimated hydrogen remaining amount B is smaller than the minimum amount of hydrogen F required to reach the second hydrogen station from the destination plus the amount of hydrogen D planned to be used at the destination (B<F+D), the identifying unit picks out hydrogen ST candidates that are reachable from the current location and exist in the vicinity of the route from the current location to the destination. The calculation unit calculates the estimated hydrogen consumption amount Y from the current location to the destination via the candidate hydrogen ST, calculates the estimated hydrogen consumption amount Z from the candidate hydrogen ST to the destination, and calculates the estimated hydrogen remaining amount B' when the vehicle reaches the destination from the candidate hydrogen ST using formula 1 (B'=100-Z). Note that in formula 1, 100 is used on the assumption that the vehicle will be fully filled with hydrogen at the candidate hydrogen ST to be visited, but this can be changed depending on the situation.
The route setting unit then searches whether there is a hydrogen ST where B'≧F+D, and if not, notifies the user that the destination cannot be reached in a single stop at the hydrogen ST and terminates the search, or it may search for a route that includes stops at two or more hydrogen STs.
On the other hand, if there is a hydrogen station for which B'≧F+D, the route setting unit selects the hydrogen station for which Y is the smallest from among the multiple hydrogen station candidates, and determines it as the first hydrogen station.
Then, the route from the current location to the destination is changed to a route that passes through the first hydrogen station, and the route is determined as the guide route.

Figure 4 is a diagram showing an example of a case in which a route is guided to satisfy the condition B≧F+D or B'≧F+D, where the condition is satisfied without stopping at a hydrogen ST, a case in which the condition is not satisfied but a case in which the route is guided to satisfy the condition without stopping at a hydrogen ST, and a case in which the condition is satisfied.
As a premise, the hydrogen tank will be full at 100 at the current location and when stopping at the hydrogen station, and the minimum amount of hydrogen required F to reach the second hydrogen station from the destination will be at least 30 hydrogen, and the planned amount of hydrogen to be used at the destination will be at least 20 hydrogen, leaving a total of 50 as the amount of hydrogen required C (C = F + D) when reaching the destination.
(i) Route 1 in Case 1 is a case in which the condition B≧F+D is met without hydrogen refueling, (ii) Route 1 in Case 2 is a case in which the condition B≧F is not met without hydrogen refueling, Route 2 is a case in which hydrogen is refueled but the condition B'≧F is not met (a case in which hydrogen is wasted due to a nearby hydrogen ST), Route 3 is a case in which hydrogen is refueled and the condition B'≧F is met but the condition B'≧F+D is not met, and Route 4 is a case in which hydrogen is refueled and the condition B'≧F+D is met.
In the example of Figure 2, when stopping at a hydrogen ST, (ii) routes 3 and 4 in case 2 all satisfy the conditions, but in the example of Figure 4, (ii) only route 4 in case 2 satisfies the conditions, so route 4 is selected.

Other Embodiments
If you do not set a destination and are driving without paying attention to the amount of hydrogen remaining, you may find that you are low on hydrogen before you know it and are already unable to reach the nearest hydrogen station (or that you still have hydrogen remaining but are unable to get to the hydrogen station).
Therefore, even if a destination has not been set, the distance between the nearest hydrogen ST and the current location can be calculated in the background, and a hydrogen ST guidance caution can be displayed on the display before there is a possibility that the nearest hydrogen ST will not be reached.

FIG. 5 is a flowchart showing an example of guidance provided by the navigation device of the present disclosure when a destination has not been set.
First, the acquisition unit acquires the current location.
Thereafter, the acquisition unit acquires the current hydrogen amount A and the hydrogen consumption amount X that is expected to be consumed up to the nearest hydrogen ST.
The calculation unit calculates the expected remaining hydrogen amount B (B=A-X) upon arrival at the nearest hydrogen ST and the required hydrogen amount C (here, this may be a margin to ensure that hydrogen does not run out upon arrival) required upon arrival at the destination.
If the estimated remaining hydrogen amount B is smaller than the required hydrogen amount C (B<C), the route planning unit displays a caution message on the navigation system or information terminal about guiding the user to a hydrogen ST and ends the guidance.

Claims (5)

A navigation device that is mounted on a fuel cell vehicle having a fuel cell that uses hydrogen gas as a fuel gas and performs route guidance for the fuel cell vehicle,
An acquisition unit that acquires a current amount of hydrogen A and an amount of hydrogen consumption X that is expected to be consumed up to the destination;
an identification unit that identifies a first hydrogen station that is present in the vicinity of a route from a current location to the destination and a second hydrogen station that is closest to the destination;
A calculation unit that calculates an expected remaining amount of hydrogen B (B=A-X) upon arrival at the destination and a required amount of hydrogen C upon arrival at the destination;
A path setting unit,
when the estimated remaining amount B of hydrogen is smaller than the required amount C of hydrogen (B<C), the route setting unit changes the route from the current location to the destination to a route that passes through the first hydrogen station ;
The required amount of hydrogen C is a minimum required amount of hydrogen F required to reach the second hydrogen station from the destination,
The acquisition unit acquires a planned hydrogen usage amount D to be used at the destination,
the route setting unit performs route search so as to leave a minimum required amount of hydrogen F for reaching the second hydrogen station from the destination and the planned amount of hydrogen usage D;
The navigation device is characterized in that, when a predetermined location is set when setting the destination, the route setting unit issues a command to confirm whether or not hydrogen is required at the destination . 2. The navigation device according to claim 1 , wherein the planned hydrogen usage amount D is a value that is statistically calculated from a user input value or a destination attribute. 3. The navigation device according to claim 1, wherein the route setting unit issues an alarm when there is a risk that the amount of hydrogen F required to reach the second hydrogen station from the destination will fall below a minimum amount F required during use of hydrogen at the destination. A navigation device as described in any one of claims 1 to 3, wherein when the planned hydrogen usage amount D is a value statistically calculated from the destination attributes, the acquisition unit compares the amount of hydrogen consumption E actually consumed at the destination with the planned hydrogen usage amount D to calculate an error , accumulates data on the error, and corrects the planned hydrogen usage amount D in accordance with the error. 5. The navigation device according to claim 1, wherein, in the route change, the route setting unit selects, from among the two or more first hydrogen stations, a hydrogen station that has a minimum amount of hydrogen consumption Y that is expected to be consumed from the current location to the destination via the hydrogen station.

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