JP2008174193A - Fuel residual quantity display system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel residual quantity display system capable of knowing a precise fuel residual quantity in light of influences of liquid level fluctuation due to traveling condition of a vehicle and inclination of a road. <P>SOLUTION: It is determined whether a detection condition of a fuel residual quantity in a fuel tank of a vehicle is a stable condition or an unstable condition. When the detecting condition is determined to be stable, a current fuel residual quantity value is calculated by a predetermined first calculation algorithm. When the detecting condition is determined to be unstable, a current fuel residual quantity value is calculated by a second calculation algorithm designed to reduce a calculation error predicted when applying the first calculation algorithm under the unstable condition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel remaining amount display system.

  In recent years, meters mounted on vehicles have been digitized to improve performance, and the displayed information has also increased, contributing to improvements in user convenience. Among them, a fuel fuel gauge (hereinafter sometimes referred to as a fuel gauge) is provided, and this fuel gauge allows the driver to know the approximate distance that can be traveled. However, since the remaining fuel data obtained from the fuel sensor installed in the fuel tank is directly affected by the fluctuation of the liquid level due to the running state of the vehicle and the inclination of the road surface, it is difficult to ensure display accuracy and stability. "Fluctuation" or "Deviation from true value" may occur, and it may be difficult to know the exact remaining fuel amount.

  Therefore, the longitude, latitude, and altitude data of the nodes constituting each road is stored, and the road type (city road, suburban road, highway, etc.) of each section of the guide route is determined from this data. In addition to checking and detecting the height difference or road gradient for each section, the fuel consumption for each section can be obtained using these results, and the fuel consumption until arrival at the destination can be obtained with high accuracy. As a result, an in-vehicle navigation device has been devised that has a function of detecting whether or not the vehicle can reach the destination with fuel loaded thereon (see Patent Document 1).

  Further, a travel route on which the vehicle will travel in the future is detected, and the farthest final filling station among the gas stations located within the travelable distance of the vehicle with respect to the remaining amount of fuel is searched for on the detected travel route. A navigation system has been devised that includes display means for displaying the last gas station on the travel route on map information (see Patent Document 2).

  In addition, when it is determined whether or not there is a facility that can replenish energy within the travelable distance corresponding to the current remaining amount of energy on the set travel route, and at least it can travel to a facility that can replenish energy Guides you to refuel at that facility, and if you are unable to travel to the next facility that can replenish energy and are driving on a motorway at that time, the nearest refueling at the next exit If you are driving on a road other than a motorway at that time, search for and set the route to the nearest facility that can supply energy. A navigation system has been devised (see Patent Document 3).

JP-A-10-197272 JP 2000-39328 A JP 2000-46572 A

  In the example of Patent Document 1, a storage medium for storing all the fuel consumption rates between the nodes is required, which increases the cost of the apparatus. In addition, since the fuel consumption rate is set uniformly regardless of the vehicle, there is a problem in that the driving state is not taken into account and an accurate required fuel amount cannot be calculated. There is also a problem that the required fuel amount cannot be calculated when the destination is not set. Furthermore, since the influence of the liquid level fluctuation due to the traveling state of the vehicle and the inclination of the road surface is not taken into account, there is a problem that an accurate required fuel amount cannot be calculated.

  In the examples of Patent Document 2 and Patent Document 3, the influence of the liquid level fluctuation due to the running state of the vehicle and the inclination of the road surface is not considered in the detection of the remaining fuel amount (energy remaining amount). And the problem of “deviation from true value” still remains.

  Against the background of the above problems, an object of the present invention is to provide a fuel remaining amount display system capable of accurately knowing the remaining amount of fuel in consideration of the influence of the liquid level fluctuation due to the running state of the vehicle and the inclination of the road surface. There is.

Means for Solving the Problems and Effects of the Invention

  A fuel remaining amount display system for solving the above problems includes a fuel remaining amount detecting means for detecting a remaining amount of fuel in a fuel tank of a vehicle, and a fuel remaining amount detection value by the remaining fuel amount detecting means for a predetermined time. Fuel remaining amount detection value sampling means for sampling at intervals, current fuel remaining amount calculation means for calculating the current fuel remaining amount value based on the sampled fuel remaining amount detection value, and the calculated current fuel remaining amount value Current fuel remaining amount value storing means for storing while updating, and fuel remaining amount displaying means for displaying the current fuel remaining amount based on the stored value of the current fuel remaining amount value, The fuel remaining amount detection means has a detection state determination means for determining whether the detection state is a stable state or an unstable state, and when the detection state is determined to be a stable state, Predetermined While calculating the current fuel remaining value by one calculation algorithm, if it is determined that the detection state is unstable, the calculation error expected when the first calculation algorithm is applied in the unstable state The present fuel remaining amount value is calculated by a second calculation algorithm designed to reduce the current.

  With the above configuration, it is possible to take into account the effects of liquid level fluctuations due to vehicle running conditions and road slopes based on the state of fuel remaining detected by the fuel remaining amount detection means, and to calculate an accurate current fuel remaining value can do. Further, by properly using the calculation algorithm according to the detection state, an increase in the processing load of the remaining fuel amount display system can be suppressed.

  The fuel remaining amount display system according to the present invention stores road map data together with predetermined unstable region specific data for which it is predicted that the remaining amount of fuel is detected in an unstable state. Storage means and position specifying means for specifying the current position of the vehicle on the road map data, and the detection state determining means is based on whether or not the current position of the vehicle belongs to the unstable region on the road map data. Thus, it can be configured to determine whether or not the detection state is an unstable state.

  With the above configuration, the storage capacity can be smaller than the configuration storing the fuel consumption rate between the nodes. In addition, there may be cases where the vehicle does not become unstable depending on the driving state of the vehicle, but since the uniform fuel consumption rate is not set in the configuration of the present invention, it is possible to respond flexibly and calculate an accurate current fuel remaining value. can do.

  The fuel remaining amount detection value sampling means in the fuel remaining amount display system of the present invention samples the fuel remaining amount detection value corresponding to one calculation of the current fuel value a plurality of times, and the first calculation algorithm is: The representative remaining amount detection value obtained based on the plurality of remaining fuel amount detection values may be calculated as the current remaining fuel amount value.

  During the period in which the detection state is stable, the sampled fuel remaining amount detection values do not vary greatly. With the above configuration, since it is not necessary to use a complicated algorithm, it is possible to obtain an effect that the calculation time is fast and the processing load for calculation is low. Further, by using a plurality of fuel remaining amount detection values, a more accurate current fuel remaining amount value can be calculated.

  Further, the representative remaining amount detection value in the remaining fuel amount display system of the present invention can be configured to be an average value of a plurality of remaining fuel amount detection values.

  A method of using a mean value as a representative value is generally used, and an algorithm for calculating the mean value is well known. Also, with the above configuration, an accurate current fuel remaining value can be calculated with a simple algorithm.

  In addition, the representative remaining amount detection value in the fuel remaining amount display system of the present invention may be configured to be the median of a plurality of fuel remaining amount detection values.

  The median is a median value that is the middle value of a data string when data is arranged in ascending or descending order. When the number of data is an even number, the median value is two, and the average of the median values is the median. Even with the above-described configuration, there is no large variation in the plurality of sampled fuel remaining amount detection values. Therefore, an accurate current fuel remaining amount value can be calculated with a simple algorithm.

  Further, the representative remaining amount detection value in the fuel remaining amount display system of the present invention can be configured to be the minimum value of a plurality of fuel remaining amount detection values.

  Even with the above-described configuration, there is no large variation in the plurality of sampled fuel remaining amount detection values. Therefore, an accurate current fuel remaining amount value can be calculated with a simple algorithm. Further, in this case, since the actual remaining fuel amount value is also displayed in a small amount, there is an effect that the driver can be promptly refueled. On the contrary, since it is not displayed more than the actual fuel remaining value, it is possible to prevent the driver from misidentifying that “there is still enough fuel”.

  The fuel remaining amount display system according to the present invention stores road map data together with predetermined unstable region specific data for which it is predicted that the remaining amount of fuel is detected in an unstable state. Storage means and position specifying means for specifying the current position of the vehicle on the road map data, and the detection state determining means is based on whether or not the current position of the vehicle belongs to the unstable region on the road map data. Determining whether or not the detection state is an unstable state, and the road map data storage means stores the specific information of the unstable region as the position specifying data of the gas station. The second calculation algorithm calculates the current fuel remaining amount value by setting the calculation time period of the representative remaining amount detection value shorter than the first calculation algorithm when the current position is at the gas station. It can also be configured to.

  During the refueling, the liquid level fluctuation is large, and the remaining fuel amount detection value fluctuates (increases) greatly in a short time. With the above configuration, it is possible to follow fluctuations in the fuel remaining amount detection value, and to calculate an accurate current fuel remaining amount value even when the vehicle is not traveling.

  The fuel remaining amount display system according to the present invention includes a travel history information acquisition unit that acquires travel history information of a vehicle within a period in which the detection state determination unit detects an unstable state, and the acquired travel history information Fuel consumption estimation calculation means for estimating and calculating fuel consumption based on the fuel consumption amount, and the second calculation algorithm is configured to calculate the current fuel remaining amount value based on the estimated and calculated fuel consumption amount You can also.

  In recent years, a sensor or the like for acquiring a travel history is attached to a vehicle in order to improve user convenience and maintainability. With the above configuration, it is possible to estimate and calculate the fuel consumption without adding new parts and devices.

  The travel history information acquisition means in the remaining fuel amount display system of the present invention comprises travel distance measurement means for measuring the travel distance of the vehicle and average vehicle speed calculation means for calculating the average vehicle speed of the vehicle, and estimates fuel consumption. The calculation means can be configured to estimate and calculate the fuel consumption based on the travel distance and the average vehicle speed.

  The odometer and the speedometer are always attached to the vehicle. With the above configuration, it is possible to estimate and calculate the fuel consumption amount with a low-cost configuration without adding new parts and devices.

  Further, the second calculation algorithm in the fuel remaining amount display system of the present invention performs an abnormality determination of the fuel remaining amount detection value sampled in an unstable state based on a predetermined abnormality determination condition, and the abnormality determination The present fuel remaining amount value can be calculated based on the remaining fuel remaining amount detected value excluding the detected fuel remaining amount detected value.

  Also with the above configuration, the current fuel remaining value can be calculated with a simple configuration and a low processing load.

  Further, in the second calculation algorithm in the fuel remaining amount display system of the present invention, the abnormality determination of the fuel remaining amount detection value is performed based on whether or not the detected value belongs to a predetermined normal value range. It can also be configured.

  For example, if the normal value range of the remaining fuel amount detection value is set as the fluctuation range of the remaining fuel amount detection value in the stable state, the abnormal value can be eliminated. With the above configuration, the current fuel remaining value can be calculated with a simple configuration and a low processing load.

  The fuel remaining amount display system of the present invention further includes a traveling state information acquisition unit that acquires the traveling state information of the vehicle, and the second calculation algorithm is performed within a period during which the detection state determination unit detects an unstable state. It can also be configured to correct the current fuel remaining amount value based on the acquired traveling state information.

  According to the above configuration, correction according to the running state can be performed, so that a more accurate current fuel remaining value can be calculated.

  Further, the traveling state information acquisition means in the fuel remaining amount display system of the present invention can be configured to detect the inclination angle of the vehicle as the traveling state information.

  In recent years, vehicle navigation devices have become widespread. In many cases, a vehicle navigation apparatus is provided with a sensor that detects an inclination angle. Also, a four-wheel drive vehicle is often provided with a sensor that detects an inclination angle. With the above configuration, the current fuel remaining value can be corrected with a simple configuration and a low processing load.

  Further, the running state information acquisition means in the remaining fuel amount display system of the present invention can be configured to detect the acceleration of the vehicle as the running state information.

  Since acceleration is the rate of change of vehicle speed, it can be detected with a vehicle speed sensor. The vehicle speed sensor is provided in almost all vehicles. Also with the above configuration, the current fuel remaining value can be corrected with a simple configuration and a low processing load.

  The fuel remaining amount display system according to the present invention includes a fuel injection signal acquisition unit that acquires a fuel injection signal for performing fuel injection in a vehicle engine, and a period during which the detection state determination unit detects an unstable state. And a fuel injection amount estimation calculation means for estimating and calculating the fuel injection amount based on the fuel injection signal acquired in step (b), and the second calculation algorithm calculates the current fuel remaining amount value based on the estimated fuel injection amount. It can also be configured to calculate.

  In a fuel injection type engine, the amount of fuel injected into each cylinder is calculated according to the running state of the vehicle. Since the fuel is injected by the injector, the fuel injection amount is calculated as the energization time to the injector. With the above configuration, if a fuel injection signal for controlling energization / non-energization to the injector is measured or acquired, the fuel injection amount at that time can be estimated and calculated, and as a result, the current fuel remaining value can be calculated. Become.

  The fuel remaining amount display system of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a remaining fuel amount display system 200 and related in-vehicle devices. The fuel remaining amount display system 200 includes a vehicle navigation device (hereinafter also referred to as a navigation device) 100 and a meter unit 400, which are network-connected by an in-vehicle LAN (Local Area Network) 27 (described later). ing.

  The configuration of the fuel remaining amount display system 200 may be a configuration in which the navigation device and the meter unit are combined into one system product in addition to FIG. For example, FIG. 2 shows a configuration in which each of the navigation device 201 and the meter unit 202 includes control circuits 201 a and 202 a including a microcomputer, and FIG. 3 shows a configuration in which the navigation device and the meter unit are configured as a single unit 203. Each has a configuration including control circuits 203a and 203b. Further, as shown in FIG. 4, the navigation device and the meter unit may be configured as a single unit 204 and may include an integrated control circuit 204a.

  FIG. 5 is a block diagram showing the configuration of the meter unit 400. The meter unit 400 includes a fuel sensor 401, a vehicle speed sensor 404, a display unit 416, a LAN (Local Area Network) I / F (interface) 417, a control circuit 408 connected to these, and the like.

  The control circuit 408 is configured as an ordinary computer, and is a well-known CPU 481, ROM 482, RAM 483, I / O 484 as an input / output circuit, A / D conversion unit 486, drawing unit 487, clock IC 488, flash memory 490, and these A bus line 485 is provided for connecting the above configurations. The CPU 481 performs control using the control program 482p and data stored in the ROM 482.

  The control circuit 408 includes a fuel remaining amount detection value sampling means, a current fuel remaining amount calculation means, a detection state determination means, a position specifying means, a fuel consumption amount estimation calculation means, a travel state information acquisition means, and a travel distance measurement. It corresponds to a means, an average vehicle speed calculation means, and a fuel injection amount estimation calculation means.

  The A / D conversion unit 486 includes a well-known A / D (analog / digital) conversion circuit, and converts analog data input from the fuel sensor 401 to the control circuit 408 into digital data that can be calculated by the CPU 481, for example. .

  The drawing unit 487 generates display screen data to be displayed on a color liquid crystal display included in the display unit 416 (described later) from display data and display color data stored in the ROM 482 or the flash memory 490.

  The clock IC 488 is also called a real-time clock IC, and sends or sets clock / calendar data in response to a request from the CPU 481. The CPU 481 acquires date / time information from the clock IC 488. Further, date information may be generated based on a real-time counter included in the CPU 481. The acquired date / time information is displayed on, for example, a display unit 416 (described later).

  The flash memory 490 is a rewritable semiconductor storage medium in which information and data necessary for the operation of the meter unit 400 are stored. Note that the flash memory 490 retains stored contents even when the meter unit 400 is turned off. The flash memory 490 corresponds to the current fuel remaining value storage means of the present invention.

  The fuel sensor 401 is provided in a fuel tank of a vehicle (not shown), for example, and the resistance value of a well-known potentiometer provided in the floating attachment portion changes depending on the floating position that rises and falls according to the position of the fuel level. Thus, a voltage value generated according to the resistance value is sent to the control circuit 408. In the control circuit 408, the voltage value is converted into a digital value by the A / D converter 486 and the remaining fuel amount is obtained by calculation. The fuel sensor 401 corresponds to the remaining fuel amount detecting means of the present invention.

  The vehicle speed sensor 404 includes a rotation detection unit such as a known rotary encoder, and is installed near the wheel mounting unit, for example, to detect the rotation of the wheel and send it to the control circuit 408 as a pulse signal. The control circuit 408 converts the rotation speed of the wheel into the speed of the vehicle. The vehicle speed sensor 404 corresponds to the travel history information acquisition unit of the present invention.

  The display unit 416 includes a known mechanical meter or color liquid crystal display. The color liquid crystal display includes a dot matrix LCD (Liquid Crystal Display) and a driver circuit (not shown) for performing LCD display control. The driver circuit uses, for example, an active matrix driving method in which a transistor is attached to each pixel so that the target pixel can be reliably turned on and off, and a display command sent from the control circuit 408 (drawing unit 487) and Display is performed based on the display screen data. Moreover, you may use an organic EL (ElectroLuminescence: electroluminescence) display and a plasma display as a display device. The display unit 416 corresponds to the fuel remaining amount display means of the present invention.

  A LAN I / F 417 is an interface circuit for exchanging data with other in-vehicle devices and sensors via the in-vehicle LAN 27. Further, data from each sensor may be taken in via the LAN I / F 417. The LAN I / F 417 corresponds to the fuel injection signal acquisition means of the present invention.

  By having the above-described configuration, the meter unit 400 has the remaining fuel amount acquired by the fuel sensor 401, the vehicle speed acquired from the vehicle speed sensor 404, or the engine speed acquired from the engine ECU 500 via the in-vehicle LAN 27. Are displayed on the display unit 416.

  FIG. 6 shows a configuration of a vehicle navigation device (hereinafter abbreviated as a navigation device) 100. The navigation device 100 includes a position detector 1, a map data input device 6, an operation switch group 7, a remote control (hereinafter referred to as remote control) sensor 11, a voice synthesis circuit 24 for performing voice guidance, a speaker 15, a memory 9, and a display. 10, a transceiver 13, a hard disk device (HDD) 21, a LAN I / F 26, a control circuit 8 connected thereto, a remote control terminal 12, and the like.

  The position detector 1 is a well-known geomagnetic sensor 2, a gyroscope 3 that detects the rotational angular velocity of the vehicle, a distance sensor 4 that detects the travel distance of the vehicle, and a GPS receiver that detects the position of the vehicle based on radio waves from a satellite. Machine 5 is provided. Since these sensors 2, 3, 4, and 5 have errors of different properties, they are configured to be used while being complemented by a plurality of sensors. Depending on the accuracy, some of the above-described sensors may be used, and further, a steering rotation sensor or a wheel sensor of each rolling wheel, such as a vehicle speed sensor 23, may be used. The position detector 1 corresponds to the position specifying means of the present invention.

  As the operation switch group 7, for example, a touch panel 22 integrated with the display device 10 or a mechanical switch is used. The touch panel 22 is pressed when an electric circuit is wired on the screen of the display 10 in the X-axis direction and the Y-axis direction through a gap called a spacer on a glass substrate and a transparent film, and the user touches the film. Since the voltage value changes due to short-circuiting of a part of the wiring, a so-called resistance film method for detecting this as a two-dimensional coordinate value (X, Y) is widely used. In addition, a known so-called capacitance method may be used. In addition to the mechanical switch, a pointing device such as a mouse or a cursor may be used. Moreover, the mechanical switch in the operation switch group 7 is disposed in an escutcheon that covers the display 10 and its periphery and serves as a design frame, for example.

  It is also possible to input various instructions using the microphone 31 and the voice recognition unit 30. In this method, a voice signal input from the microphone 31 is processed by a voice recognition technique such as a well-known hidden Markov model in the voice recognition unit 30, and converted into an operation command corresponding to the result. Various instructions can be input through the operation switch group 7, the remote control terminal 12, the touch panel 22, and the microphone 31.

  The control circuit 8 is configured as a normal computer, and connects a well-known CPU 81, ROM 82, RAM 83, I / O 84 as an input / output circuit, A / D conversion unit 86, drawing unit 87, clock IC 88, and these components. A bus line 85 is provided. The CPU 81 controls the navigation program 21p and data stored in the HDD 21. The CPU 81 controls the reading / writing of data to / from the HDD 21. In addition, a program for performing a minimum necessary operation as the navigation device 100 may be stored in the ROM 82 in a case where the data read / write control from the CPU 81 to the HDD 21 becomes impossible. The control circuit 8 corresponds to the position specifying means of the present invention.

  The A / D conversion unit 86 includes a well-known A / D (analog / digital) conversion circuit, and converts analog data input from the position detector 1 or the like to the control circuit 8 into digital data that can be calculated by the CPU 81, for example. It is.

  The drawing unit 87 generates display screen data to be displayed on the display unit 10 from map data 21m (described later) stored in the HDD 21 or the like, display data, and display color data.

  The watch IC 88 has the same configuration as the watch IC 488 of the meter unit 400. Further, date and time information included in the GPS signal received by the GPS receiver 5 may be used. The date information may be generated based on a real-time counter included in the CPU 81.

  The memory 9 is composed of a rewritable device such as an EEPROM (Electrically Erasable & Programmable Read Only Memory) or a flash memory, and stores information and data necessary for the operation of the navigation apparatus 100. Has been. The memory 9 holds the stored contents even when the navigation device 100 is turned off. Further, instead of the memory 9, information and data necessary for the operation of the navigation device 100 may be stored in the HDD 21. Further, information and data necessary for the operation of the navigation device 100 may be stored separately in the memory 9 and the HDD 21.

  The display 10 has the same configuration as the color liquid crystal display included in the display unit 416 of the meter unit 400, and performs display based on the display command and display screen data sent from the control circuit 8 (drawing unit 87).

  The transceiver 13 is, for example, a VICS (Vehicle Information and Communication System: registered trademark) center 14 by an optical beacon or a radio beacon output from a transmitter (not shown) provided along the road. It is a device for receiving road traffic information from or receiving FM multiplex broadcasting. Moreover, it is good also as a structure which can be connected to external networks, such as the internet, using the transmitter / receiver 13. FIG.

  The speaker 15 is connected to a well-known voice synthesis circuit 24, and the digital voice data stored in the memory 9 or the HDD 21 in accordance with a command from the navigation program 21p is converted into analog voice by the voice synthesis circuit 24 and sent out. Note that speech synthesis methods include a recording / editing method in which speech waveforms are stored as they are or after being encoded and connected as necessary, and a text synthesis method in which corresponding speech is synthesized from character input information.

  Further, by communicating with the ETC on-vehicle device 17, it is possible to capture the fee information received by the ETC on-vehicle device 17 from the roadside device (not shown) into the navigation device 100. Further, the ETC on-vehicle device 17 may be connected to an external network and communicate with the VICS center 14 or the like. For example, the well-known DSRC (Dedicated Short Range Communication) technology is used for the ETC vehicle-mounted device 17.

  In addition to the navigation program 21p, the HDD 21 stores map data 21m, which is a map database including so-called map matching data for improving position detection accuracy and road map data representing road connections. The map data 21m stores predetermined map image information for display and road network information including link information and node information. The link information is predetermined section information constituting each road, and includes position coordinates, distance, required time, road width, number of lanes, speed limit, and the like. The node information is information defining an intersection (branch road) or the like, and is composed of position coordinates, the number of right / left turn lanes, a connection destination road link, and the like. In addition, data indicating whether or not traffic is possible is set in the inter-link connection information. The map data 21m corresponds to the road map data storage means of the present invention.

  In addition, in the HDD 21, auxiliary information for route guidance, entertainment information, and other data can be written independently by the user and stored as user data 21u. Data and various information necessary for the operation of the navigation device 100 are also stored as the database 21d.

  The navigation program 21p, map data 21m, user data 21u, and database 21d can be added and updated from the storage medium 20 via the map data input device 6. The storage medium 20 is generally a CD-ROM or DVD based on the amount of data, but may be another medium such as a memory card. Moreover, you may use the structure which downloads data via an external network.

  The vehicle speed sensor 23 has the same configuration as the vehicle speed sensor 404 of the meter unit 400. The control circuit 8 converts the obtained number of wheel rotations into a vehicle speed, calculates an expected arrival time from the current position of the vehicle to a predetermined location, and calculates an average vehicle speed for each travel section of the vehicle. The vehicle speed sensor 404 may also be used.

  The communication unit 25 is configured as a known wireless communication device and is used for data communication with an external network. The communication unit 25 may be configured as an interface circuit between the mobile communication terminal and the control circuit 8 for performing data communication by connecting a mobile communication terminal (not shown) such as a mobile phone.

  The LAN I / F 26 is an interface circuit for exchanging data with other in-vehicle devices such as the meter unit 400 and sensors via the in-vehicle LAN 27. Further, data from the vehicle speed sensor 23 or connection to the ETC vehicle-mounted device 17 may be performed via the in-vehicle LAN 27.

  With this configuration, the navigation device 100 allows the user to operate the operation switch group 7, the touch panel 22, the remote control terminal 12, or from the microphone 31 when the navigation program 21 p is activated by the CPU 81 of the control circuit 8. When a route guidance process for displaying a destination route on the display 10 is selected from a menu (not shown) displayed on the display 10 by voice input, the following process is performed.

  That is, first, the user searches for a destination. The destination search method is, for example, a method of specifying an arbitrary point on the map, a method of searching from the area where the destination is located, a method of searching from the telephone number of the destination, or a name of the destination from the Japanese syllabary table There are a method of searching by inputting the number of characters stored in the memory 9 as a facility frequently used by the user. When the destination is set, the current position of the vehicle is obtained by the position detector 1, and a process for obtaining an optimum guide route to the destination from the current position is performed. Then, the guidance route is displayed on the road map on the display 10 so as to guide the user to the appropriate route. As a method for automatically setting an optimum guide route, a method such as the Dijkstra method is known. In addition, at least one of the display 10 and the speaker 15 performs notification of a message according to an operation guidance or an operation state.

  The acceleration sensor 35 is configured as, for example, a piezoelectric acceleration sensor including a piezoelectric element that generates an electric charge when it receives an inertial force. The piezoelectric acceleration sensor has a structure in which a piezoelectric element is sandwiched between bases having a constant mass. The relationship between the acceleration applied to the acceleration sensor 35 and the inertial force applied to the piezoelectric element is expressed by Newton's second law, and the generated charge is linearly proportional to the acceleration. Therefore, if the generated charge is acquired as a voltage value and the voltage value is A / D converted, the acceleration can be calculated.

  The inclination sensor 36 detects the inclination angle of the vehicle, and generally uses an acceleration sensor (35) that can detect the acceleration and gravitational acceleration of the vehicle and a vehicle speed sensor (23) that detects a vehicle speed pulse (for example, , See Patent Document 4). When the acceleration sensor is installed so that the sensitivity is increased in the plane including the vehicle traveling direction (pitch) and the vehicle vertical direction (roll), the acceleration sensor is calculated by comparing the acceleration direction of the vehicle and the sensitivity direction component of the acceleration sensor of gravity acceleration. Detect and output composition. Thereby, the inclination angle and inclination direction of the vehicle can be acquired.

JP 2000-055678 A

  The current fuel remaining amount calculation process will be described with reference to FIG. This process is included in the control program 482p and is repeatedly executed together with other processes of the control program 482p. First, a voltage value (fuel remaining amount detection value) corresponding to the fuel level in the fuel tank obtained from the fuel sensor 401 is obtained and stored in the data table storage area 490a of the flash memory 490. A current fuel remaining value is calculated with reference to a data table in which the relationship between the voltage value and the current fuel remaining value is defined (S11). A predetermined arithmetic expression may be used.

  Next, vehicle speed information is acquired from the vehicle speed sensor 404 (S12). If the vehicle is equipped with ABS (Anti Lock Brake System), vehicle speed information can be obtained from the ABS ECU (Electronic Control Unit) via the in-vehicle LAN 27 or the like. Good.

  Next, the current position information of the vehicle is acquired from the navigation device 100 (S13). Then, it is determined whether or not the current position of the vehicle is included in the unstable region. The unstable region is a region in which the detection state of the remaining amount of fuel is predicted to be unstable, such as a mountainous area or a road with a continuous curve, and is included in the map data 21m of the navigation device 100. . Data similar to the map data 21m may be stored in the flash memory 490.

  If the current position of the vehicle is not included in the unstable region (S14: No), it is determined that the vehicle is in a stable state. Therefore, the current remaining fuel amount value calculation process in the stable state, which is the first calculation algorithm of the present invention, is performed. Execute (S15). At this time, the unstable time stored in the flash memory 490 or the like is cleared. Then, when the end condition is satisfied (S16: Yes), this process ends. If the end condition is not satisfied (S16: No), the process returns to step S13.

  On the other hand, when the current position of the vehicle is included in the unstable region (S14: Yes), it is determined that the vehicle is unstable. Therefore, the current remaining fuel amount in the unstable state is the second calculation algorithm of the present invention. A value calculation process is executed (S17). At this time, date and time information is acquired from the clock IC 488 and the time when the state becomes unstable is stored in the flash memory 490 or the like. If the end condition is satisfied (S18: Yes), this process ends. If the end condition is not satisfied (S18: No), the process returns to step S13.

  At this time, when the acceleration of the vehicle detected by the acceleration sensor 35 exceeds a predetermined threshold regardless of being included in the unstable region, the current remaining fuel amount value calculation process in the unstable state May be executed. Similarly, when the vehicle inclination direction and the inclination angle acquired by the inclination sensor 36 exceed a predetermined threshold value, the current fuel remaining amount value calculation process in the unstable state may be executed. Good. Alternatively, the current fuel remaining amount calculation process in the unstable state may be executed when both the acceleration of the vehicle and the inclination direction and the inclination angle of the vehicle exceed predetermined threshold values. Information on the acceleration sensor 35 and the inclination sensor 36 is acquired from the navigation device 100 at a predetermined timing.

  Examples of the termination condition in step S16 or step S18 include a case where a predetermined time has elapsed since the start of the process, or a case where an execution timing of another process prior to the process is reached.

  With reference to FIG. 8, the current fuel remaining amount value calculation process in the stable state corresponding to step S <b> 15 in FIG. 7 will be described. First, the fuel remaining amount detection value sampled by the fuel sensor 401 is acquired by a predetermined number (n) such as 16 in the past (S31).

  The remaining fuel detection value is sampled at a predetermined time interval t (ms), for example, as an interrupt process independent of this process. The sampling time interval t is smaller than the execution interval of the current fuel remaining value calculation process in the stable state. In the above case, the current fuel remaining value in the stable state is obtained after at least 16 sampling processes are executed. A calculation process is executed. The sampled fuel remaining amount detection value is stored in the flash memory 490 or the RAM 483.

  Next, a representative remaining amount detection value D of the acquired remaining fuel amount detection value is calculated (S32). In step S32, an average value of the acquired remaining fuel amount detection values is calculated as the representative remaining amount detection value D. The representative remaining amount detection value D may be a median (median value) or a minimum value in addition to the average value.

  Finally, the calculated representative remaining amount detection value D is replaced with the current fuel remaining amount value (S33). Using this new current remaining fuel value, the remaining fuel amount is displayed on the display unit 416.

(Current fuel remaining amount calculation process 1 in unstable state)
With reference to FIG. 9, the current fuel remaining amount value calculation process in an unstable state, which corresponds to step S <b> 17 in FIG. 7, will be described. First, the calculation of the current fuel remaining amount value using the fuel remaining amount detection value acquired from the fuel sensor 401 is stopped (S51). Next, vehicle speed information is acquired from the vehicle speed sensor 404 or the like (S52).

  Next, based on the acquired vehicle speed information, the travel distance and average vehicle speed of the vehicle in the period determined to be unstable are calculated (S53). Since the number of pulses output from the vehicle speed sensor 404 when the wheel makes one revolution and the travel distance per wheel rotation (equivalent to the circumference of the wheel) are known, the travel distance should be calculated from the number of rotations of the wheel. Can do. Further, the average vehicle speed can be calculated by dividing the travel distance by the period during which it is determined to be unstable, or by obtaining the average of a plurality of calculated past vehicle speeds. The period during which the state is determined to be unstable can be measured using date / time information of the clock IC 488, for example.

  Next, based on the fuel consumption estimation calculation data table stored in the data table area 490a or a predetermined calculation formula, the fuel consumption during the period determined to be in an unstable state is estimated and calculated (S54). FIG. 10 shows an example of a fuel consumption amount estimation calculation data table. The fuel consumption amount estimation calculation data table is represented by the relationship between the travel distance and the fuel consumption amount. V1, V2, and V3 are average vehicle speed values, and V1> V2> V3. That is, if the average vehicle speed value is large even if the travel distance is the same, the fuel consumption amount increases. In this process, the fuel consumption during the period determined to be an unstable state is integrated.

  Returning to FIG. 9, the new current fuel is obtained by subtracting the estimated fuel consumption from the current fuel remaining value calculated immediately before the determination of the unstable state, which is stored in the flash memory 490. An estimation calculation is performed as the remaining amount value D (S55).

  Finally, the current fuel remaining value is replaced with the current fuel remaining value D estimated and calculated above (S56). Using this new current remaining fuel value, the remaining fuel amount is displayed on the display unit 416.

(Current fuel remaining value calculation process 2 in unstable state)
With reference to FIG. 11, another example of the current remaining fuel amount value calculation process in the unstable state corresponding to step S <b> 17 in FIG. 7 will be described. First, the sampled fuel remaining amount detection value stored in the flash memory 490 or the RAM 483 is referred to determine whether or not the data is reliable. Whether or not there is reliability is determined using at least one or both of the following.
(1) When the fuel remaining amount detection value is not increased with respect to the current fuel remaining amount value that is stored in the flash memory 490 and is calculated immediately before it is determined to be an unstable state, it is reliable. Judgment.
(2) The fuel remaining amount detection value belongs to a predetermined normal value range stored in the flash memory 490 with respect to the current fuel remaining amount value calculated immediately before being determined to be an unstable state. The case is determined to be reliable.

  When it is determined that the fuel remaining amount detection value data is reliable (S71: Yes), the data is acquired as current fuel remaining amount calculation data (S72). When a predetermined number (n) of current fuel remaining value calculation data, such as 16, is acquired, a representative remaining amount detection value D is calculated (S73). In step S73, the average value of the acquired fuel remaining amount detection values is calculated as the representative remaining amount detection value D. The representative remaining amount detection value D may be a median (median value) or a minimum value in addition to the average value.

  Finally, the calculated representative remaining amount detection value D is replaced with the current fuel remaining amount value (S74). Using this new current remaining fuel value, the remaining fuel amount is displayed on the display unit 416.

(Current fuel remaining value calculation process 3 in unstable state)
With reference to FIG. 12, another example of the current remaining fuel amount value calculation process in the unstable state corresponding to step S <b> 17 in FIG. 7 will be described. First, the fuel remaining amount detection value sampled by the fuel sensor 401 is acquired by a predetermined number (n) such as 16 in the past (S91).

Next, the traveling state of the vehicle is acquired, and a correction value corresponding to the traveling state is acquired with reference to the correction table stored in the data table area 490a (S92). The running state uses at least one or both of the following.
(1) The acceleration of the vehicle acquired by the acceleration sensor 35 is acquired from the navigation device 100 via the in-vehicle LAN 27.
(2) The vehicle tilt angle and tilt direction acquired by the tilt sensor 36 are acquired from the navigation device 100 via the in-vehicle LAN 27.

  FIG. 13 shows an example of the acceleration correction table. In the example of FIG. 13, it is defined as a correction coefficient corresponding to the acceleration. Positive acceleration occurs when the vehicle accelerates, and negative acceleration occurs when the vehicle decelerates. The correction value is defined in consideration of the shape of the fuel tank and the mounting position of the fuel sensor 401.

  FIG. 14 shows an example of the tilt angle correction table. In the example of FIG. 14, the correction coefficient is defined using the vehicle tilt angle and the tilt direction as parameters. The tilt angle is expressed as an elevation angle with respect to the tilt direction. The inclination direction of 0 degree corresponds to the forward direction of the vehicle. If the inclination angle is detected at this time, the vehicle is traveling uphill. Further, the inclination direction of 180 degrees corresponds to the rearward direction of the vehicle, and if the inclination angle is detected at this time, the vehicle is traveling downhill. The angle in the tilt direction increases clockwise.

  Each correction table may define a corrected fuel remaining amount detection value.

  Returning to FIG. 12, the sampled fuel remaining amount detection value is corrected based on the acquired correction value (S93). That is, a coefficient corresponding to the acceleration and / or the tilt angle is obtained, and the coefficient is multiplied by the sampled fuel remaining amount detection value.

  Then, a representative remaining amount detection value D of the corrected fuel remaining amount detection value is calculated (S94). In step S94, the average value of the acquired fuel remaining amount detection values is calculated as the representative remaining amount detection value D. The representative remaining amount detection value D may be a median (median value) or a minimum value in addition to the average value.

  Finally, the calculated representative remaining amount detection value D is replaced with the current fuel remaining amount value (S95). Using this new current remaining fuel value, the remaining fuel amount is displayed on the display unit 416.

(Current fuel remaining value calculation process 4 in unstable state)
With reference to FIG. 15, another example of the current fuel remaining amount calculation process in the unstable state corresponding to step S <b> 17 of FIG. 7 will be described. First, the calculation of the current remaining fuel value using the remaining fuel detection value acquired from the fuel sensor 401 is stopped (S111). Next, a fuel injection signal is acquired from the engine ECU 500 via the in-vehicle LAN 27 (S112).

  The fuel injection signal is for controlling an injector for injecting fuel into a cylinder of the engine. For example, a pulse signal as shown in FIG. 16 is used. Fuel is injected during Ton when the pulse signal is in the ON state.

  Returning to FIG. 15, the Ton of the fuel injection signal is measured, and the fuel consumption after the unstable state is calculated from the fuel injection signal based on a preset arithmetic expression, table, etc. (S113). . As an example of calculating with an arithmetic expression, since the fuel injection amount m per unit time of the injector and the number of cylinders N of the engine are known, the period of one pulse of the fuel injection signal is T, and the execution timing of this processing is t ( msec), the fuel injection amount is obtained by the calculation formula m × Ton × (t / T) × N. This fuel consumption is integrated in an unstable state.

  Then, a value obtained by subtracting the fuel consumption calculated above from the current fuel remaining value immediately before the unstable state is set as a new current fuel remaining value D (S114).

  Finally, the calculated current fuel remaining value D is replaced with the current fuel remaining value (S115). Using this new current remaining fuel value, the remaining fuel amount is displayed on the display unit 416.

(Current fuel remaining value calculation process 5 in unstable state)
With reference to FIG. 17, the current fuel remaining amount value calculation process in the unstable state corresponding to step S <b> 17 in FIG. 7 will be described. First, the fuel remaining amount detection value sampled by the fuel sensor 401 is acquired in a predetermined number (n) such as 16 in the past (S131).

Next, it is determined whether the vehicle is refueling. The determination method uses at least one or both of the following.
(1) Judgment is made based on whether or not the current position information of the vehicle acquired from the navigation device 100 via the in-vehicle LAN 27 indicates a gas station.
(2) Judgment is made based on whether the amount of change or the rate of increase of the sampled fuel remaining amount detection value exceeds a predetermined value.

  When it is determined that the vehicle is not refueling (S132: No), the current fuel remaining amount value calculation process in the above-described stable state is executed (S136). On the other hand, if it is determined that the vehicle is refueling (S132: Yes), the representative remaining amount detection value D is calculated using the m most recently sampled fuel remaining amount detection values (S133). m is a value smaller than n, such as 8, for example. In step S133, an average value of the acquired remaining fuel amount detection values is calculated as the representative remaining amount detection value D. The representative remaining amount detection value D may be a median (median value) or a minimum value in addition to the average value.

  Then, the calculated representative remaining amount detection value D is replaced with the current fuel remaining amount value (S134). Using this new current remaining fuel value, the remaining fuel amount is displayed on the display unit 416.

  Finally, this process is repeated until it is determined that the vehicle is not refueling (S135: No → S131). Moreover, although not shown in figure, you may continue waiting until refueling is complete | finished (S135: No-> S135).

  Although the embodiments of the present invention have been described above, these are merely examples, and the present invention is not limited to these embodiments, and the knowledge of those skilled in the art can be used without departing from the spirit of the claims. Various modifications based on this are possible.

The figure which shows the structure of a fuel residual amount display system. The figure which shows another example of a structure of a fuel residual amount display system. The figure which shows another example of a structure of a fuel residual amount display system. The figure which shows another example of a structure of a fuel residual amount display system. The block diagram which shows the structure of a meter unit. The block diagram which shows the structure of the navigation apparatus for vehicles. The flowchart explaining the present fuel remaining value calculation process. The flowchart explaining the present fuel remaining amount value calculation process at the time of a stable state. The flowchart explaining the present fuel remaining amount value calculation process (1) at the time of an unstable state. The figure which shows the example of a fuel consumption amount estimation calculation data table. The flowchart explaining another example (2) of the present fuel remaining amount value calculation process at the time of an unstable state. The flowchart explaining another example (3) of the present fuel remaining amount value calculation process at the time of an unstable state. The figure which shows the example of an acceleration correction table. The figure which shows the example of an inclination angle correction table. The flowchart explaining another example (4) of the present fuel remaining amount value calculation process at the time of an unstable state. The figure which shows the example of a fuel-injection signal. The flowchart explaining another example (5) of the present fuel remaining amount calculation process at the time of an unstable state.

Explanation of symbols

1 Position detector (position identification means)
8 Control circuit (position identification means)
10 Display 21 Hard disk drive (HDD)
21m Map data (Road map data storage means)
26 LAN I / F
DESCRIPTION OF SYMBOLS 100 Vehicle navigation apparatus 200 Fuel remaining amount display system 400 Meter unit 401 Fuel sensor (fuel remaining amount detection means)
404 Vehicle speed sensor (travel history information acquisition means)
408 control circuit (fuel remaining amount detection value sampling means, current fuel remaining amount value calculation means, detection state determination means, position specifying means, fuel consumption estimation calculation means, travel state information acquisition means, travel distance measurement means, average vehicle speed calculation Means, fuel injection amount estimation calculation means)
490 flash memory (current fuel remaining value storage means)
416 Display (fuel remaining amount display means)
417 LAN I / F (fuel injection signal acquisition means)
500 Engine ECU

Claims (15)

Fuel remaining amount detecting means for detecting the remaining amount of fuel in the fuel tank of the vehicle;
Fuel remaining amount detection value sampling means for sampling the fuel remaining amount detection value by the fuel remaining amount detection means at a predetermined time interval;
A current fuel remaining amount value calculating means for calculating a current fuel remaining amount value based on the sampled fuel remaining amount detection value;
Current fuel remaining value storage means for storing the calculated current fuel remaining value while updating it;
Fuel remaining amount display means for displaying the current fuel remaining amount based on the stored value of the current fuel remaining amount value,
The current fuel remaining amount calculating means includes detection state determining means for determining whether the remaining fuel amount detected by the remaining fuel amount detecting means is in a stable state or an unstable state, and the detected state Is determined to be in a stable state, the current remaining fuel value is calculated using a predetermined first calculation algorithm, while if the detected state is determined to be in an unstable state, The remaining fuel level is calculated by a second calculation algorithm designed to reduce a calculation error expected when the first calculation algorithm is applied in an unstable state. Display system. Road map data storage means for storing road map data together with specific data of a predetermined unstable region in which the detection state of the remaining amount of fuel is predicted to be the unstable state;
Position specifying means for specifying the current position of the vehicle on the road map data,
The detection state determination means determines whether or not the detection state is an unstable state based on whether or not a current position of the vehicle belongs to the unstable region on the road map data. The fuel remaining amount display system described in 1. The fuel remaining amount detection value sampling means samples the fuel remaining amount detection value corresponding to one calculation of the current fuel value a plurality of times,
The fuel remaining amount display system according to claim 1, wherein the first calculation algorithm calculates a representative remaining amount detected value obtained based on the plurality of remaining fuel amount detected values as the current remaining fuel amount value. .   The fuel remaining amount display system according to claim 3, wherein the representative remaining amount detection value is an average value of a plurality of the remaining fuel amount detection values.   The fuel remaining amount display system according to claim 3 or 4, wherein the representative remaining amount detection value is a median of the plurality of remaining fuel amount detection values.   The fuel remaining amount display system according to any one of claims 3 to 5, wherein the representative remaining amount detection value is a minimum value of a plurality of the remaining fuel amount detection values. The road map data storage means comprises the requirements according to claim 2, and stores the unstable region specific information as gas station location specific data,
The second calculation algorithm calculates the current fuel remaining value by setting a calculation time period of the representative remaining amount detection value to be shorter than that of the first calculation algorithm when the current position is at the gas station. The fuel remaining amount display system according to any one of claims 3 to 6, wherein: Travel history information acquisition means for acquiring travel history information of the vehicle within a period in which the detection state determination means detects the unstable state;
Fuel consumption estimation calculation means for estimating and calculating fuel consumption based on the acquired travel history information,
The fuel remaining amount display system according to any one of claims 1 to 7, wherein the second calculation algorithm calculates the current fuel remaining amount value based on the estimated fuel consumption. The travel history information acquisition means includes travel distance measurement means for measuring the travel distance of the vehicle, and average vehicle speed calculation means for calculating an average vehicle speed of the vehicle,
The fuel remaining amount display system according to claim 8, wherein the fuel consumption amount estimation calculation means estimates and calculates a fuel consumption amount based on the travel distance and an average vehicle speed.   The second calculation algorithm performs an abnormality determination of the fuel remaining amount detection value sampled in the unstable state based on a predetermined abnormality determination condition, and uses the fuel remaining amount detection value determined to be abnormal. The fuel remaining amount display system according to any one of claims 1 to 9, wherein the current fuel remaining amount value is calculated based on an excluded remaining fuel remaining amount detection value.   11. The fuel remaining amount according to claim 10, wherein the second calculation algorithm performs an abnormality determination of the fuel remaining amount detection value based on whether or not the detection value belongs to a predetermined normal value range. Quantity display system. A driving state information acquisition means for acquiring the driving state information of the vehicle;
The second fuel calculation algorithm corrects the current fuel remaining amount value based on the traveling state information acquired during a period in which the detection state determination unit detects the unstable state. 11. The fuel remaining amount display system according to any one of 11 above.   The fuel remaining amount display system according to claim 12, wherein the traveling state information acquisition unit detects an inclination angle of the vehicle as the traveling state information.   The fuel remaining amount display system according to claim 12 or 13, wherein the traveling state information acquisition unit detects acceleration of the vehicle as the traveling state information. Fuel injection signal acquisition means for acquiring a fuel injection signal for performing fuel injection in the engine of the vehicle;
A fuel injection amount estimation calculation unit that estimates and calculates a fuel injection amount based on the fuel injection signal acquired during a period in which the detection state determination unit detects the unstable state;
The fuel remaining amount display system according to any one of claims 1 to 14, wherein the second calculation algorithm calculates the current fuel remaining amount value based on the estimated fuel injection amount.

Images