EP0139770A1
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Electronic odometer
Assignee: Hitachi Ltd
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Filing: 1984-04-20
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Granted: —
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Expires: 2004-04-20
Abstract
Abstract An electronic odometer employs a nonvolatile memory as a meter for displaying the cumulative distance traveled by a vehicle such as an automobile. Data on the cumulative distance traveled by the vehicle is calculated in an arithmetic unit (3) on the basis of signals from a pulse generator (1), and is written in sequence in a nonvolatile memory (7) provided with N cumulative distance data memory areas for each of predetermined distance meters. During reading, a maximum value of the cumulative distance traveled data is obtained from the N cumulative distance data memory areas in the nonvolatile memory (7). When the difference between the maximum value and the data written just before that maximum value matches a predetermined distance, this maximum value is displayed on a digital display unit (8) as the cumulative distance traveled.
Inventors
- 👤 Hirohisa Yamamura
- 👤 Shotaro Naito
- 👤 Kohzo Katohgi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 15:49
CPC Classifications
G; G01; G01C; G01C22/00; H; H03; H03K; H03K21/00; H03K21/40; H03K21/403; G01C22/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
134 words
An electronic odometer comprising: arithmetic means which receives data on distance traveled and calculates total distance traveled; determination means which determines whether a preset distance has been traveled; a non-volatile memory having N addresses into which data on total distance traveled is written one- by-one every time said preset distance is traveled; address-changing means which changes and selects N addresses of said non-volatile memory; writing means which, in response to an output of said preset distance determination means, writes the total distance calculated by said arithmetic means and changes the address in said non-volatile memory every time said preset distance is traveled; reading means which, when required, reads out data written into said non-volatile memory and inputs said data to said arithmetic means; and display means which displays results calculated by said arithmetic means.
Claim 2
Dependent Claim
134 words
An electronic odometer comprising: arithmetic means which receives data on distance traveled and calculates total distance traveled; determination means which determines whether a preset distance has been traveled; a non-volatile memory having N addresses into which data on total distance traveled is written one- by-one every time said preset distance is traveled; address-changing means which changes and selects N addresses of said non-volatile memory; writing means which, in response to an output of said preset distance determination means, writes the total distance calculated by said arithmetic means and changes the address in said non-volatile memory every time said preset distance is traveled; reading means which, when required, reads out data written into said non-volatile memory and inputs said data to said arithmetic means; and display means which displays results calculated by said arithmetic means.
Claim 3
Dependent Claim
58 words
The electronic odometer according to claim 1, wherein said reading means is provided with a determination circuit which reads out data from said non-volatile memory when power is turned on, or when the power-source voltage is restored, and which selects a maximum value from said data written every preset distance, and employs said maximum value as read data.
Claim 4
Dependent Claim
163 words
The electronic odometer according to claim 1, wherein said address-changing means is provided with a first address-changing means and a second address-changing means, a first reading means and said first address-changing means are operated by an output from said preset distance determination means, an address stored in an address in a data storage location of said non-volatile memory is changed sequentially and the content thereof is read out, the content thus read is set in said second address-changing means, data on total distance traveled is written by said writing means, the data thus written is read out by a second reading means, said data is compared by a comparator circuit with previous data to determine whether they are equal to each other, and, when they are not equal, the data are written onto said non-volatile memory by said first address-changing means and said writing means in such a manner that the address in said data storage location of said non-volatile memory is renewed.
Claim 5
Dependent Claim
188 words
The electronic odometer according to claim 1 or claim 3, wherein said reading means is provided with a means which selects a maximum value from data on total distance traveled which is stored in said data storage location of said non-volatile memory; and which determines whether the difference between said value and a data item stored immediately before said maximum value is equal to said preset distance; wherein when said difference is equal to said preset distance traveled, said maximum value is input to said arithmetic means; but when said difference is not equal to said preset distance, it is determined whether the difference between the data item stored immediately before said maximum value and the data item stored immediately before that is equal to said preset distance, so that when said difference is equal to said preset distance, said data stored immediately before said maximum value is input to said arithmetic means; but when said difference is not equal to said preset distance, the same determination is effected sequentially, and data is input to said arithmetic means when said difference becomes equal to said preset distance traveled.
Claim 6
Dependent Claim
91 words
The electronic odometer according to claim 1, wherein said address-changing is provided with a first address-changing means, a second address-changing means a power source, a power-on determination means and a power-off determination means; wherein when said output is generated by said preset distance determination means, said writing means writes addresses that are sequentially changed by said first address-changing means; and when an output is generated by said power-off determination means, said second address-changing means sequentially writes data into addresses that are different from said addresses indicated by said first address-changing means.
Claim 7
Dependent Claim
119 words
The electronic odometer according to claim 5, wherein said reading means is provided with means which reads data when an output is generated by said power-on determination means, selects a maximum value A from said data written according to said second address-changing means, selects a maximum value B from said data written according to said first address-changing means and which indicates preset distance data employs said maximum value A as a read value when a value obtained by subtracting said maximum value B from said maximum value A is less than said preset predetermined distance and has a positive sign, employs said maximum value B as a read value otherwise, and inputs said read value to said arithmetic means.
References Cited (Backward Citations)
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