JP4140459B2 - Traveling distance integrating device for moving objects - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a travel distance integrating device for a moving body that integrates the travel distance of the mobile body using a nonvolatile memory.
[0002]
[Prior art]
Conventionally, in an electronic control device for an automobile meter, when the ignition switch SW is turned on, the central processing unit (CPU) is accumulated from the non-volatile memory to the travel distance (this is integrated before the ignition switch SW is turned off). The travel distance is repeatedly accumulated according to the called travel distance and the detection output from the speed sensor, and the accumulated travel distance is repeatedly rewritten and stored in the volatile memory. (For example, refer to Patent Document 1).
[0003]
Here, every time the travel distance stored in the volatile memory increases by a certain distance, the central processing unit stores the value in the upper digit of the travel distance stored in the volatile memory in a non-volatile manner. Rewrite to memory and store.
[0004]
When the ignition switch SW is turned off, the central processing unit is supplied with power from the backup power supply circuit, and rewrites and stores the last one digit value of the travel distance stored in the volatile memory in the nonvolatile memory.
[0005]
Since the travel distance stored in the nonvolatile memory is updated in this way, the central processing unit stores the travel stored in the nonvolatile memory when the ignition switch SW is turned on even if the ignition switch SW is turned off. Since the travel distance is integrated using the distance as an initial value, an integration error does not occur when the travel distance is integrated.
[0006]
[Patent Document 1]
JP-A-6-249673
[Problems to be solved by the invention]
By the way, although the automobile is provided with a backup power supply circuit for supplying electric power directly from the in-vehicle battery to the electronic control device without going through the ignition switch, when the automobile is transported before being delivered to the user, The function of the backup power supply circuit may be stopped. In this case, the last digit value of the travel distance stored in the nonvolatile memory is not updated.
[0008]
For example, when the ignition switch SW is turned off when actually traveling 3.2 km, the last one digit value “0.2” stored in the nonvolatile memory is not updated. Therefore, after that, when the ignition switch SW is turned on, when calling the travel distance from the nonvolatile memory and storing it in the volatile memory, “3.0” (= 3 Km) is set as the upper digit value in the nonvolatile memory. However, as the last one digit value, an incorrect value is called from the non-volatile memory and stored in the volatile memory.
[0009]
For example, when “0.6” is stored as the last digit in the nonvolatile memory, “3.0” and “0.6” are stored in the volatile memory. A value (3.6 Km) larger than the actual travel distance (3.2 Km) is stored in the volatile memory. Along with this, there arises a problem that the travel distance is accumulated with an incorrect value as an initial value, and a travel distance longer than the actual travel distance is calculated.
[0010]
In view of the above points, an object of the present invention is to provide a travel distance accumulating device for a moving body that prevents the travel distance from being calculated longer than the actual distance.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a nonvolatile memory (12) for storing a traveling distance of a moving body and a main power source of the moving body are turned on. The mileage is called from the non-volatile memory, the called mileage is stored in the volatile memory (13), and the detected output from the speed sensor (30) for detecting the stored mileage and the speed of the moving body; In accordance with the travel distance stored repeatedly in the volatile memory, and non-volatile in accordance with the travel distance stored in the volatile memory. A mileage accumulating device for a moving body comprising memory control means (S250, S270) for rewriting the mileage stored in the volatile memory, wherein the memory control means is stored in the volatile memory. Each time the travel distance to be憶is increased by a first predetermined distance, the value of the upper digit is stored by rewriting the nonvolatile memory than the lower one digit of the running distance stored in the volatile memory, and, When the last digit value of the travel distance stored in the volatile memory becomes zero, zero is rewritten in the nonvolatile memory as the last digit value of the travel distance.
[0012]
As a result, when the main power of the moving body is turned on, the last one digit value of the travel distance that is called from the nonvolatile memory and stored in the volatile memory becomes zero. Calculations can be prevented.
[0013]
Further, as in the second aspect of the invention, the memory control means sets the value of the last one digit of the travel distance stored in the volatile memory to zero once after the main power supply of the mobile body is turned on. Then, if zero is rewritten and stored in the nonvolatile memory as the last digit value of the travel distance, then unless the zero as the last digit value stored in this nonvolatile memory is rewritten, The travel distance is integrated by setting the last digit value of the travel distance to zero.
[0014]
Therefore, the travel distance can be integrated with the last digit value of the travel distance set to zero without extra rewriting of the nonvolatile memory.
[0015]
Here, as in the first and second aspects of the invention, when zero is rewritten in the nonvolatile memory as the last digit value of the travel distance, and the travel distance is integrated with the last digit value of the travel distance as zero There is a possibility that the travel distance shorter than the actual travel distance is accumulated. Therefore, it is preferable to restrict rewriting zero to a non-volatile memory as the last digit value of the travel distance in accordance with the travel distance.
[0016]
Specifically, the invention according to claim 3 includes a determination means (S220) for determining whether or not the accumulated traveling distance is less than the second constant distance, and the accumulated traveling distance is the second constant. Only when the determining means determines that the distance is less than the distance, when the value of the last digit of the travel distance stored in the volatile memory becomes zero, the memory control means sets zero to the lower distance of the travel distance. It is characterized in that it is rewritten into a nonvolatile memory as a digit value.
[0017]
Incidentally, the reference numerals in parentheses of each means described above are an example showing the correspondence with specific means described in an embodiment described later.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an electrical schematic configuration of an embodiment of an automotive instrument E to which a traveling distance integrating device for a moving body of the present invention is applied. As shown in FIG. 1, the automotive instrument E is composed of a meter electronic control device 10 and a display panel 20, and the meter electronic control device 10 is composed of a central processing unit (CPU) 11, an EEPROM 12, and a RAM 13. It is configured.
[0019]
As will be described later, the central processing unit 11 performs an accumulation process for integrating the travel distance of the vehicle according to the detection output from the vehicle speed sensor 30. The vehicle speed sensor 30 is a sensor that detects the rotational speed of the driving wheel of the automobile and obtains the speed of the automobile according to the detected rotational speed.
[0020]
The EEPROM 12 is a non-volatile memory that can store data without being supplied with power, and stores a computer program. In addition, in order to store the travel distance as will be described later, the EEPROM 12 stores a fraction area for storing the last one digit value of the travel distance and an upper digit value for the upper one digit of the travel distance. A girder area is provided.
[0021]
Here, a positive voltage (hereinafter referred to as a positive voltage VIG) is applied to the central processing unit 11 and the EEPROM 12 from the positive terminal of the in-vehicle battery Ba through the ignition switch IG, and the positive electrode of the in-vehicle battery Ba is not transmitted through the ignition switch IG. A positive voltage (positive voltage V + B) is applied from the terminal through the current fuse H. Hereinafter, the function of supplying power from the in-vehicle battery Ba to the central processing unit 11 and the EEPROM 12 through the current fuse H is referred to as a backup power source.
[0022]
As shown in FIG. 2, when the travel distance is “135.5 km”, the “lower one digit value” is “0.5”, and the “upper digit” is “135”.
[0023]
The RAM 13 is a volatile memory in which stored data is erased when power is not supplied, and stores data associated with a running distance integrating process by the central processing unit 11 as will be described later.
[0024]
Next, regarding the integration processing by the central processing unit 11 of the present embodiment, (1) processing in a state where the current fuse H is attached and the backup power source is functioning, and (2) backup when the current fuse H is removed. The process will be described separately with reference to FIGS. 3 to 5 in the state where the power supply is stopped.
[0025]
3 and 4 are flowcharts showing integration processing by the central processing unit 11, FIG. 5A is a timing chart showing the state of the backup power supply, and FIG. 5B is a timing showing the operating state of the ignition switch IG. FIG. 5C is a timing chart showing an actual travel distance.
[0026]
5D is a timing chart showing data stored in the upper digit area of the EEPROM 12, FIG. 5E is a timing chart showing data stored in the fraction area of the EEPROM 12, and FIG. These are timing charts showing data stored in the fractional area of the EEPROM 12.
[0027]
(1) First, the case where the backup power supply is functioning will be described. In this case, even if the ignition switch IG is turned off, the central processing unit 11 repeatedly executes the fraction storage process shown in FIG. 3 and the upper digit storage process shown in FIG. 4 alternately.
[0028]
Hereinafter, the fraction storage process will be described prior to the upper digit storage process. The central processing unit 11 executes the computer program stored in the EEPROM 12 according to the flowchart shown in FIG.
[0029]
First, when the positive voltage VIG input from the ignition switch IG becomes less than a certain level, it is determined that the ignition switch IG is turned off by the occupant, YES is determined in S100, and the lower of the travel distance stored in the RAM 13 as will be described later. A one-digit value is stored in the fraction area of the EEPROM 12 (S110).
[0030]
Next, the upper digit storage process will be described. The central processing unit 11 executes a computer program stored in the EEPROM 12 according to the flowchart shown in FIG.
[0031]
First, from the fractional area and the upper digit area of the EEPROM 12, the lower one digit value and the upper digit value of the mileage are recalled, and the mileage is calculated by the called lower one digit value and the upper digit value. It is generated and stored in the RAM 13 (S200).
[0032]
Next, with the travel distance stored in the RAM 13 as an initial value, the travel distance is integrated by time-integrating the detection output from the vehicle speed sensor 30. Accordingly, the integrated value is displayed on the display panel 20, and the travel distance stored in the RAM 13 is rewritten using the integrated value (S210).
[0033]
Next, when it is determined NO in S220 that the rewritten travel distance (that is, the integrated value) is equal to or greater than a certain distance (for example, 100 km), the rewritten travel distance becomes the travel distance before the rewrite. In comparison, it is determined whether it has increased by 1 km or more (S260).
[0034]
Here, when it is determined that the rewritten travel distance has increased by 1 km or more compared to the travel distance before the rewrite, the upper digit of the EEPROM 12 is set to the upper digit value of the rewritten travel distance. Write to the area. Further, when the difference between the rewritten travel distance and the travel distance before the rewrite is less than 1 km and it is determined as NO, writing to the upper digit area is prohibited.
[0035]
By alternately executing the upper digit storing process and the fraction storing process as described above, the lower one digit value and the upper digit value of the accumulated travel distance are appropriately stored in the EEPROM 12 and stored. The travel distance is integrated according to each value.
[0036]
(2) Next, a case where the backup power supply is not functioning will be described. In this case, when the ignition switch IG is turned off, the central processing unit 11 is not supplied with power and cannot execute the process of step S100 in FIG. For this reason, when the ignition switch IG is on, the central processing unit 11 substantially repeats the upper digit storage process shown in FIG.
[0037]
Specifically, in S200, the lower 1 digit value and the upper digit value are called from the fraction area and the upper digit area of the EEPROM 12, and the travel distance is generated and stored in the RAM 13 (timing t1, t2 in FIG. 5). , T4). Thereafter, the process proceeds to S210 where the travel distance is accumulated using the stored travel distance as an initial value, and the accumulated travel distance is displayed on the display panel 20, and the accumulated value is rewritten and stored in the RAM 13.
[0038]
Next, when it is determined that the travel distance (that is, the integrated value) stored in the RAM 13 is less than a certain distance and YES is determined in S220, the determination of YES is made for the first time after the ignition switch IG is turned on. It is determined whether or not (S230).
[0039]
Here, when the determination of YES in S220 is made for the first time after the ignition switch IG is turned on and it is determined YES in S230, the last one digit value of the travel distance stored in the RAM 13 is “zero”. It is determined whether or not there is (S240). Then, when it is determined YES because the last digit value of the travel distance stored in the RAM 13 is “zero”, the process proceeds to S250 and “zero” is stored in the fractional area of the EEPROM 12.
[0040]
For example, in FIG. 5, when “3.0” is stored in RAM 13 by rewriting from “2.9” to “3.0” at timing t 3, In this example, “zero” is stored in the fraction area of the EEPROM 12 and “3” as the value of the upper digit is stored in the upper digit area of the EEPROM 12.
[0041]
Thereafter, when the integrated value increase determination (S260) and the upper digit value storage process (S270) are executed, the process returns to S200. As long as the integrated value of the travel distance does not exceed a certain distance, the travel distance storage process (S200), the integrated display storage process (S210), the initial determination (S230), the fraction zero determination (S240), and the fraction storage process (S250) ), Integrated value increase determination (S260), and upper digit value storage processing (S270) are repeatedly executed.
[0042]
Next, the effect of this embodiment is demonstrated. That is, when the EEPROM 12 for storing the travel distance of the automobile and the ignition switch IG are turned on, the travel distance is called from the EEPROM 12 and the recalled travel distance is stored in the RAM 13, and the stored travel distance and the automobile are stored. A central processing unit 11 that repeatedly accumulates the travel distance according to the detection output from the speed sensor 30 that detects the speed of the vehicle, and repeatedly rewrites and stores the accumulated travel distance in the RAM 13. Then, every time the travel distance stored in the RAM 13 increases by a certain distance, the central processing unit 11 sets the value of the digit higher than the last one digit in the travel distance stored in the RAM 13 in the upper digit area of the EEPROM 12. When the value of the last digit of the travel distance stored in the RAM 13 becomes zero, the zero is rewritten in the EEPROM 12 as the last digit value of the travel distance.
[0043]
As a result, when the ignition switch IG is turned on, the last one digit value of the travel distance that is called from the EEPROM 12 and stored in the RAM 13 becomes zero, thereby preventing the travel distance from being calculated longer than the actual travel distance. be able to.
[0044]
Further, the central processing unit 11 sets zero to the lower one digit of the travel distance when the lower one digit value of the travel distance stored in the RAM 13 becomes zero only once after the ignition switch IG is turned on. Since the value is rewritten and stored in the lower digit area of the EEPROM 12 as a value, the traveling distance is integrated with the lower digit value of the traveling distance set to zero unless the “zero” stored in the lower digit area of the EEPROM is subsequently rewritten. be able to.
[0045]
Therefore, the travel distance can be integrated with the last digit value of the travel distance set to zero without extra rewriting of the data in the EEPROM 12.
[0046]
Further, when zero is rewritten in the EEPROM 12 as the last digit value of the travel distance and the travel distance is accumulated with the last digit value of the travel distance as zero, there is a possibility that a travel distance shorter than the actual travel distance is accumulated. Therefore, it is preferable to rewrite zero in the nonvolatile memory as the last digit value of the travel distance only when the travel distance is less than a certain distance.
[0047]
(Other embodiments)
In the above embodiment, an example in which an automobile is used as a moving body has been described. However, the present invention is not limited thereto, and a train may be used as a moving body.
[0048]
In the above-described embodiment, an example in which an automobile provided with the ignition switch IG is used as an automobile has been described. However, the present invention may be applied to an electric automobile, a hybrid automobile, or the like instead.
[0049]
In the above embodiment, the travel distance is integrated so as to include a value after the decimal point, for example, “135.5 km”. However, the travel distance is not limited thereto, and the travel distance may be integrated as an integer value.
[0050]
Hereinafter, the correspondence relationship between the above-described embodiment and the configuration of the scope of the claims will be described. The ignition switch IG is turned ON to turn on the central processing unit (CPU) 11 of the meter electronic control device 10 from the in-vehicle battery Ba, the EEPROM 12, and Supplying power to the RAM 13 corresponds to turning on the main power.
[Brief description of the drawings]
FIG. 1 is a diagram showing an electrical schematic configuration of an embodiment of an automotive instrument according to the present invention.
FIG. 2 is an explanatory diagram of the operation of the central processing unit of FIG.
FIG. 3 is a flowchart showing a part of processing of the central processing unit of FIG. 1;
4 is a flowchart showing the rest of the processing of the central processing unit of FIG. 1. FIG.
FIG. 5 is a timing chart showing the operation of the central processing unit of FIG. 1;
[Explanation of symbols]
10 ... Electronic control unit for meter, 11 ... Central processing unit (CPU),
12 ... EEPROM, 13 ... RAM.

Claims (3)

A non-volatile memory (12) for storing the travel distance of the moving body;
When the main power of the mobile body is turned on, the travel distance is called from the nonvolatile memory and the called travel distance is stored in the volatile memory (13), and the stored travel distance and the mobile body Accumulating means (S200, S210) for repeatedly accumulating the travel distance according to the detection output from the speed sensor (30) for detecting the speed, and repeatedly rewriting and storing the accumulated travel distance in the volatile memory. ,
A travel distance accumulating device for a moving body comprising memory control means (S250, S270) for rewriting the travel distance stored in the nonvolatile memory in accordance with the travel distance stored in the volatile memory,
Each time the travel distance stored in the volatile memory is increased by a first fixed distance, the memory control means is a value in the upper digit of the travel distance stored in the volatile memory. Is rewritten and stored in the non-volatile memory, and when the last digit value of the travel distance stored in the volatile memory becomes zero, the zero is set as the last digit value of the travel distance. A travel distance accumulating device for a moving object, wherein the nonvolatile memory is rewritten.   The memory control means sets the travel to zero when the value of the last digit of the travel distance stored in the volatile memory becomes zero only once after the main power supply of the mobile body is turned on. The travel distance integrating device for a moving body according to claim 1, wherein the distance is rewritten and stored in the nonvolatile memory as a last digit value of the distance. Determination means (S220) for determining whether or not the accumulated travel distance is less than a second fixed distance;
Only when the determination means determines that the accumulated travel distance is less than a second fixed distance, the value of the last digit stored in the volatile memory becomes zero. The travel distance integrating device for a moving body according to claim 2 , wherein the memory control means rewrites the zero in the nonvolatile memory as the last digit value of the travel distance.

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