JPH07239237A - Electronic trip distance recorder - Google Patents

Abstract

PURPOSE:To obtain a word to be updated by uniquely storing the newest total trip distance in accordance with data of a higher digit even when a region storing a lower digit of the trip distance consists of more than one words. CONSTITUTION:A distance detection means 1 outputs a pulse signal in accordance with a trip distance. A distance calculation means 2 calculates a trip distance based on the pulse signal. A non-volatile memory means 4 has an exclusive memory region consisting of words of which number corresponds to an updating frequency of each digit for storing the trip distance for each column by using BCD. A control means 3 updates the data in the memory means 4 and determines the word to be updated in accordance with the data in an upper digit of the memory region consisting of a plurality of words every time the trip distance reaches a unit trip distance. An indication means 6 indicates the trip distance based on the data in the memory means 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic odometer used as an odometer or trip meter for vehicles such as automobiles and motorcycles.

[0002]

2. Description of the Related Art When an electronic odometer is used as, for example, an odometer of a vehicle, it is necessary to keep a past total mileage even if a battery abnormality (voltage drop, disconnection, etc.) occurs. A non-volatile storage means is used (Japanese Patent Laid-Open No. 57-198810). As for the configuration of the non-volatile memory, considering the allowable number of updates of the non-volatile memory (about 10,000 times), the total mileage is stored in the storage area for the lower digit (1Km digit and 10Km digit) and the upper digit (100Km digit). ~ 100000Km
Divided into storage area for digits), unit travel distance (eg 1km)
Rewriting the lower digit storage area by 1 bit for each, storing the carry in the upper digit storage area, and providing error correction means in the lower digit storage area and the upper digit storage area, respectively. (Japanese Patent Laid-Open No. 5-322594).

[0003]

By the way, in recent years, due to the progress of semiconductor technology, the performance of the non-volatile storage means has been improved, and the allowable number of updates has been greatly improved. Total is desired.

[0004]

In order to solve the above-mentioned problems, the present invention provides a distance detecting means for outputting a pulse signal according to a traveling distance, and a distance calculating means for calculating a traveling distance according to the pulse signal. , The mileage is BCD for each digit
A non-volatile storage means having a dedicated storage area for the number of words corresponding to the update frequency of each digit for storing, and updating the data in the storage means each time the travel distance reaches a unit travel distance, and a plurality of words With respect to the storage area constituted by, there is provided a control means for determining a word to be updated by the data of the storage area in the upper digit, and a display means for displaying the total traveling distance according to the data of the storage means. It is characterized by that.

The number of words is the maximum total travel distance / (allowable update count × minimum digit distance × unit travel distance) for digits including the unit travel distance, and maximum total travel distance for other digits. It is characterized in that it is obtained from a calculation result of distance / (allowable update count × minimum distance of digit), and a digit whose calculation result is less than 1 is 1 word.

Alternatively, the word number is the maximum total mileage / (allowable update count × minimum digit distance × unit mileage) for a digit including the unit mileage, and the unit for the nearest upper digit. The number of digits including the mileage is the same as the number of digits other than those, and the digits other than those are calculated from the calculation result of maximum total mileage / (allowable update count x minimum distance of digit), and the digit less than 1 is 1 word For the digit including the unit mileage and its nearest upper digit, the word for updating is determined by the data in the storage area of the upper digit other than the digit including the unit mileage and the nearest upper digit. It is characterized by updating at the same time in word units.

[0007]

Even if the area for storing the lower digit of the traveling distance is a plurality of words, the latest total traveling distance is stored, that is, the word for updating is uniquely obtained from the data of the upper digit.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on each embodiment shown in the accompanying drawings.

FIG. 1 is a block diagram in which the electronic odometer according to the present invention is used as an odometer of a vehicle. Distance detecting means 1 is provided on a wheel or axle of the vehicle and outputs a pulse signal for each rotation speed. The sensor is used as a distance input of the arithmetic control unit 2 including a microcomputer.

The distance calculation means 2 receives a distance input, counts the number of pulses, and outputs a control signal to the control means 3 for each predetermined unit traveling distance.

In response to the control signal, the control means 3 reads the data of the non-volatile storage means 4 composed of an EEPROM or the like, which will be described later, and obtains the total travel distance at the immediately preceding time point, and the unit travel is based on that value. The data in the storage means 4 is updated (erased / written) with the sum of the distances as the latest total traveled distance. At the same time, a display signal is output via the drive unit 5 so as to update the display content of the display unit 6. As a method of obtaining the total traveling distance at the immediately preceding time point, it is not always necessary to read the data in the storage means 4, and if a battery (not shown) is connected, the RAM in the distance calculation means 2
The data stored in the volatile storage means (not shown) such as the above may be read out and obtained by the control means 3.

Reference numeral 7 is an error correction means, and the detection and correction of an error in the storage means 4 by the error correction means 7 and the reading and updating of the storage means 4 by the control means 3 are made by the applicant of the present application. JP-A-5-32259
This is the same as the description in Japanese Patent Publication No. 4 publication, and a detailed description thereof will be omitted.

Next, the configuration and operation of the storage means 4 will be described with reference to FIGS. In the present embodiment, the allowable number of updates is 50,000 times, the unit travel distance is 2 km, and the maximum total travel distance is 1 million km (however, if the display means 5 displays all 6 digits with the lowest digit being 1 km, The maximum total mileage that can be displayed is
999999Km) and the numerical value 0-9 of each digit is BCD (2
Each word is stored in each word of the storage means 4 by an evolved decimal code. Each word has 5 bits (ordinarily 4 bits, but the most significant bit of each word is set as a parity bit and the same word is used for odd parity). The number of "0" s is always an odd number), 1Km digit is 10 words, 10Km digit is 2 words, and each digit of 100Km or more is 1 word. Formula 1 shown below (for a digit including a unit travel distance, that is, for a 1 Km digit in this embodiment),
It was obtained from the calculation result based on the equation 2 (for digits other than the digits obtained by the equation 1). However, L is the maximum total mileage (1 million K
m), N is the allowable number of updates (50,000 times), P is the minimum distance of a digit for obtaining the word number W, M is a unit travel distance (2 km), and one digit is for a digit whose calculation result is less than 1.

W = L / (N × P × M) ... Equation 1

W = L / (N × P) Equation 2

FIG. 2 shows a dedicated storage area of the number of words according to the update frequency of each digit of the storage means 4 based on the calculation result. That is, 10 is a 1 Km digit storage area for 10 words at addresses 00 to 09, 20 is a 10 Km digit storage area for 2 words at addresses 20 to 21, and 30, 40, 50 and 60 are 100 Km,
It is a storage area for each digit of 1000 Km, 10000 Km and 100000 Km, and each address is one word at 22, 23, 24 and 25. Each of the storage areas 10 to 60 is composed of three sets of a, b, and c, and stores the same data at the same address. However, in the following description, only a will be described and the other sets will be omitted.

A feature of the present invention is that the address to be updated in the storage area for a digit having a plurality of addresses (1 Km digit and 10 Km digit in this embodiment) is determined by the upper digit data (travel distance). The details will be described below.

Addresses 00 to 09 are assigned to the 1-Km digit storage area 10, and as shown in FIG. 3, the higher-order 100-Km digit storage area 30, that is, the lower value (0 ~ 9) uniquely determine the address to be updated. In other words, addresses 00-09 are switched every 100km.

Further, the storage area 20 for the 10 Km digit is set to the address 2
0 and 21 are assigned, and as shown in FIG. 3, the storage area 40 for the 1000 Km digit which is the upper digit, that is, the address 23
The address to be updated is uniquely determined by the value (0 or 1) of the lower 1 bit of the data. That is, address 20,
21 changes every 1000 km running.

FIGS. 4 and 5 show another embodiment of the present invention. The difference from the above embodiment is that the unit traveling distance M is 1 km.
As a result, the number of words in the 1 Km digit storage area 10 becomes 20 according to the equation 1.

Therefore, in the 1 Km digit storage area 10, addresses 00 to 19 are allocated, and as shown in FIG.
By the higher-order 100Km digit storage area 30, that is, the lower value of the data at address 22 (0 to 9) and the 1000Km digit storage area 40, that is, the lower 1-bit value of the data at address 23 (0 or 1), The address to be updated is uniquely determined. In other words, the addresses 00 to 09 are switched every 100 km traveling, and the first half (address 00 to 09) and the latter half (address 10 to 19) are alternately used every 1000 km traveling. The other points are the same as in the above-mentioned embodiment.

According to these embodiments, by storing the lower digit as well as the upper digit in the BCD, the storage method of the traveling distance can be basically based on the decimal number, and the conversion method to the display means 6 can be performed. However, there is an advantage that the reliability of mileage data can be improved with a small memory capacity and the number of gates, especially when the logic circuit is used. The reason why such a configuration is possible is that the performance of the non-volatile storage means is improved and the allowable number of updates is significantly improved (the 1 Km digit storage area 10 in FIGS. 2 and 4). While the bit of each word is updated 50,000 times while running 1 million km, the first non-volatile memory 4 of FIG. 2 of Japanese Patent Application Laid-Open No. 5-322594, which is a prior application of the present applicant, is disclosed. Bit is updated 10,000 times when running the same distance).

FIG. 6 shows still another embodiment of the present invention. In each embodiment, three sets of a, b and c are prepared and the same data is stored in each set, and different data is stored at the same address. If it is stored, the data that is considered to be correct is estimated by the majority vote and used for the display (for details, see Japanese Patent Publication No. 1-46005).
On the other hand, in the present embodiment, a configuration for generating a check bit for detecting a bit error of stored data (for details, see Japanese Patent Application Laid-Open No. 5-296 filed by the applicant of the present application).
781).

That is, each of the 1 Km digit storage area 10 and the 10 Km digit storage area 20 constituting the storage means 4 is 4 bits × 20.
Each of the addresses 00 to 19 is composed of a word and has a common address 00 to 19, and a 5-bit check bit area 70 is added to each of the addresses 00 to 19.

Further, the 100 Km digit storage area 30 and the 1000 Km digit storage area 40 constituting the storage means 4 are each 4 bits × 1.
It is composed of words and has an address 1A in common, and a 5-bit check bit area 80 is added to this address 1A. Similarly, the storage area 50 for 10000 Km digits and the storage area 60 for 100 000 Km digits which compose the storage means 4 are each composed of 4 bits × 1 word, and have an address 1B in common, and this address 1B has 5 bits. Bit inspection bit area 90
Is added.

In such a configuration, the 1 Km digit storage area 10
Addresses 00 to 19 are allocated to the 10 Km digit storage area 20 and, like the 1 Km digit storage area 10 of the other embodiment, the lower digit of the data in the 100 Km digit storage area 30 which is the upper digit thereof. Value (0-9) and the value of the lower 1 bit (0 or 1) of the data in the 1000 Km digit storage area 40 uniquely determines the address to be updated. In other words, addresses 00-19 are
It switches every 100km running, and the first half (address 00-09) and the latter half (address 10-19) are used alternately every 1000km running. That is, the digit including the unit mileage (1 km digit)
For the above, in the calculation result of Equation 1, the most significant digit (10Km digit) that is the closest to it is the same number as the digit including the unit mileage,
For other digits (100Km to 100000Km digits),
Calculated by the calculation result of Formula 2, the digit whose calculation result is less than 1 is 1 word, and the digit including the unit mileage and its immediate upper digit are the digit including the unit mileage and its immediate upper digit. High-order digits other than (100Km digits and 1000Km
The word to be updated is determined by the data in the storage area of the digit), and the word is updated at the same time.

According to this embodiment, in addition to the advantages of the above-mentioned embodiments, each digit storage area 10-90 has only one set, and the same data is provided in a plurality of sets (3 sets of a, b and c). The storage means 4 can be downsized and can be easily updated as compared with the above-described embodiments in which the storage is performed. Further, since the 1Km digit storage area 10 and the 10Km digit storage area 20 are updated at the same address, the 1Km digit storage area 10 and the 10Km digit storage area 20 are updated at the same time to shorten the update time. Becomes

In the present invention, the traveling distance is BC for each digit.
Since the data is stored in D, it has a dedicated storage area having the number of words according to the update frequency of each digit, and therefore the capacity (the number of bits) of the storage means 4 is larger than that of the conventional one.
However, since the storage means 4 generally uses a commercially available general-purpose memory (standard products such as 1K bit and 2K bit), there is a margin in capacity from the beginning, and the capacity is slightly increased as in each of the above embodiments. However, the memory that has been conventionally used can be used as it is without increasing the cost. Further, the present invention is not limited to the above-mentioned respective embodiments, and, for example, the setting of the unit traveling distance or the like can be arbitrarily determined. Further, not only the traveling distance but also other vehicle information, for example, the usage time of the vehicle can be similarly stored and displayed in each of the embodiments.

[0029]

According to the present invention, since the method of storing the traveling distance is based on the decimal number, the conversion means to the display means is simplified, the configuration can be simplified, and the effect of downsizing and cost reduction can be achieved. Have. In addition, even if there are multiple areas that store the lower digits of the mileage, the latest storage area can be uniquely obtained from the data of the upper digits, so the effort for updating can be simplified and the update time can be reduced. Since the latest storage area is uniquely obtained, it also contributes to the reduction of errors. In particular, it is possible to provide an electronic odometer corresponding to the improvement of the performance of the non-volatile storage means, that is, the drastic improvement of the allowable number of updates, due to the recent progress of semiconductor technology.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a storage unit of the embodiment.

FIG. 3 is an explanatory diagram showing a method of updating a storage unit according to the embodiment.

FIG. 4 is an explanatory diagram showing a configuration of a storage unit according to another embodiment of the present invention.

FIG. 5 is an explanatory view showing a method of updating the storage means of the embodiment.

FIG. 6 is an explanatory diagram showing a configuration of a storage unit according to still another embodiment of the present invention.

[Explanation of symbols]

 1 distance detection means 2 distance calculation means 3 control means 4 storage means 5 driving means 6 display means 7 error correction means 10 1 Km digit storage area 20 10 Km digit storage area 30 100 Km digit storage area 40 1000 Km digit storage area 50 10000 Km digit storage area 60 100000 Km digit storage area 70 to 90 Inspection bit area

Claims (3)

[Claims] 1. A distance detecting means for outputting a pulse signal according to the traveling distance, a distance calculating means for calculating a traveling distance according to the pulse signal, and a BCD for each digit of the traveling distance.
A non-volatile storage means having a dedicated storage area for the number of words corresponding to the update frequency of each digit for storing, and updating the data in the storage means each time the travel distance reaches a unit travel distance, and a plurality of words With respect to the storage area constituted by, there is provided a control means for determining a word to be updated by the data of the storage area in the upper digit, and a display means for displaying the total traveling distance according to the data of the storage means. An electronic odometer characterized in that 2. The number of words is the maximum total travel distance / (allowable update count × minimum digit distance × unit travel distance) for a digit including the unit travel distance, and the maximum total travel for other digits. Distance / (allowable number of updates x minimum distance of digits)
The electronic odometer according to claim 1, wherein the digit obtained by the calculation result of 1 and the digit less than 1 is set to 1 word. 3. The word number is the maximum total mileage / (allowable update count × minimum digit distance × unit mileage) for a digit including the unit mileage, and the unit for the nearest upper digit. The number of digits including the mileage is the same as the number of digits other than those, and the digits other than those are calculated from the calculation result of maximum total mileage / (allowable update count x minimum distance of digit), and the digit less than 1 is 1 word For the digit including the unit mileage and its nearest upper digit, the word for updating is determined by the data in the storage area of the upper digit other than the digit including the unit mileage and the nearest upper digit. The electronic odometer according to claim 1, wherein the odometer is simultaneously updated in units of words.