JPH0426693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic odometer mounted on a vehicle.

In recent years, display instruments such as liquid crystal displays have become popular for vehicle instruments, and have gained popularity due to their good visibility and variety of designs. This display instrument is driven by an electronic circuit centered on a microcomputer and is generally called an electronic instrument, but in the past, only odometers could be made electronic. This is because the battery powers the electronic circuits installed in the vehicle, so when the main switch is turned off, the voltage supply to the electronic circuits is cut off, and the odometer must always remember the distance traveled up to that point. However, if the voltage supply to the memory circuit in the electronic circuit is cut off, memory becomes impossible. However, with recent progress in research and development of non-volatile memory, it has become possible to convert odometers into electronic instruments.
It is gradually being adopted.

This kind of odometer has a light passing hole in a disc that rotates in proportion to the rotation speed of the wheel, and the light emitting part and the light receiving part of the photocoupler are placed on both sides of the disc, so that the rotation speed of the wheel can be adjusted. Although it is configured to convert into a number of pulses and add them, it will also work if, for example, high-frequency pulses are artificially input, making it possible to falsify the distance traveled. As a countermeasure to this problem, as disclosed in Japanese Patent Application Laid-Open No. 57-148211, there is a system that does not add frequencies even if the input frequency is higher than the maximum vehicle speed, but even with this configuration, the frequency is within the maximum vehicle speed. If you input the frequency pulse for a long time, the mileage display will eventually go around and reach 0 km.
It is possible to go back and make the distance traveled shorter than the actual distance.

The present invention has been devised in view of the foregoing, and provides a method for determining one or more digits in one cycle when the odometer display is made by selectively applying voltage to segments of a commonly used Japanese digit. By changing the display form for the first and second rounds, it is possible to display a distance that can be distinguished between the first round and the second and subsequent rounds of the odometer.

Hereinafter, the present invention will be explained in detail based on Examples.

Figures 1 to 4 show one embodiment of the present invention, with Figure 1 showing the display format for the first round, and Figure 2 showing the display format for the second and subsequent rounds, respectively. are doing. In this display, the display is performed by selectively applying voltage to the seven segments of the Japanese character, but the selection of some numbers is different between the first round and the second round onwards. Although the numbers 6 and 7 are shown in different forms in FIGS. 1 and 2, in this embodiment each decimal number is displayed in the form shown in FIGS. 3a and 3b. FIG. 3a shows the display format for the first round, and FIG. 3b shows the display format for the second and subsequent rounds. In addition to the above 6, 7, the format of 9, 0 is different, but in this case, the number of display digits is 6 digits including the number of points and below, and the display format is different. Only about 4.7% of the total numbers can be composed of other numbers, and in this case, it is possible to tell whether it is the first round or after the second round after driving for at most 600 meters.

In order to make the display formats different after the first and second rounds as described above, the configuration for driving the odometer may be configured as shown in FIG. 4, for example. That is,
A determination circuit is included in the configuration of a counter 1 that counts input pulses generated when the vehicle runs, a decoder 2 that is a drive circuit that receives the output from the counter 1, and a display 3 that displays the output of the decoder 2. 4 is added, and when the value of the counter 1 has gone through one cycle, the judgment circuit 4 gives a change command signal to the decoder 2, and the decoder 2 that receives this signal displays the form of the subsequent displayed numbers in the form shown in FIG. 3b. Yo,
This is to send an output signal that changes the selection of the supply voltage to the seven segments forming the numbers to the display 3, and by this, the display form for the first and second rounds can be displayed differently. be.

As described above, according to this embodiment, it is possible to distinguish whether it is the first round or the second round or later, depending on the form of the numerical value displayed on the odometer.

In this example, the display format for the four numbers after the first and second round was different, but even if it is a single number, if it is a general odometer that is displayed every 100 meters, it will be displayed for a period of 1 kilometer. Since it is always possible to determine whether it is the first round or the second round or later, it is sufficient if there is one or more numbers that make the display format different between the first round and the second round. In addition, the format of the displayed number may be other than that shown in the above example. For example, the number "1" is displayed in two vertical segments in the first round as in the above example, and in the second and subsequent rounds, the number "1" is displayed in two vertical segments as in the above example. It may also be displayed in one segment. Also, after the second round, it is not necessary that they all have the same form; in short, it is sufficient that at least one of the ten numbers in the decimal system that represents each round after the second round has a different form from the first round. Therefore, the display driving configuration does not need to be the one shown in FIG. 4 as long as it can produce such a display. Further, although the present embodiment includes a determination circuit 4, a logic circuit of a decoder 2 that changes the display format according to the carry signal output from the counter 1, and a display format that is stored in the display device 3 as a memory. If there is, a method of changing the memory by switching a circuit for switching the memory may be considered.

As mentioned above, in an electronic odometer mounted on a vehicle that is displayed by selectively applying voltage to the Japanese character segments, at least one of the digits displayed after the second round of the odometer is displayed once. According to the present invention, in which the display format is different from the displayed numbers, it is possible to obtain an electronic odometer that can distinguish whether it is the first round or not based on the format of the displayed numbers.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention; Figure 1 is an example of the values that appear in the first round of the odometer; Figure 2 is an example of the values that appear in the second round;
Figure 3a is an example of ten numbers used in the first round,
FIG. 3b is an example of ten numbers used in the second round, and FIG. 4 is a diagram showing an example of the display drive configuration. 1: Counter, 2: Decoder, 3: Display,
4: Judgment circuit.

Claims (1)

[Claims] 1. An electronic odometer mounted on a vehicle whose display is performed by selectively applying voltage to the sun-shaped segments includes a counter that counts pulses generated when the vehicle is running; A drive circuit that applies a voltage to a predetermined segment according to an output from the segment, and a determination circuit that outputs a change command signal to the drive circuit to change the form of displayed numbers when the value of the counter completes one cycle. Electronic odometer.