JPS6233525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic odometer for a vehicle that accurately displays the accumulated distance traveled.

Vehicles are equipped with an odometer that displays cumulative distance traveled, and is usually incorporated into a speedometer. Mechanical counters have been used for odometers, but recently electronic odometers have been increasingly used to electronically display cumulative mileage. As a conventional electronic odometer for a vehicle, there is one shown in FIG. 1, for example. When converting a vehicle-type odometer to a computer, it is necessary to ensure that the accumulated mileage data does not disappear even if the vehicle's battery is removed, so that the memory contents are retained even when the power is turned off. Semiconductor non-volatile memory is often used. However, semiconductor non-volatile memory has the property that its memory contents can usually be rewritten only about ¹⁰⁵ times. The odometer shown in Figure 1 focuses on this point. 1 is a distance sensor that outputs a pulse every time the vehicle travels a certain distance, and 2 is a distance sensor that counts the number of pulses from distance sensor 1 and calculates the cumulative distance traveled. 3 is a display device that displays the contents of the counter, that is, the distance traveled; 4 is a semiconductor nonvolatile memory; 5 is a semiconductor nonvolatile memory that transfers the stored content of the nonvolatile memory 4 to the counter 2 when the ignition switch 6 is turned on; This is a control device that stores the contents of the counter 2 in the nonvolatile memory 4 when the ignition switch 6 is turned off. With this configuration, there is no need to rewrite the contents of the counter to non-volatile memory every time a pulse arrives from the distance sensor, and the mileage data in the counter can only be written to non-volatile memory only when the ignition switch is turned off. This is convenient because it can extend the lifespan of the memory.

This electronic odometer is configured to transfer mileage data between the counter and non-volatile memory by turning the ignition switch on and off. If you push the ignition switch manually to start the engine) or if you drive the vehicle by coasting with the ignition switch turned off due to some trouble or other reason, the distance traveled during that time will not be accumulated. (The engine stops) If you remove the battery, the mileage data in the counter at that time will not be transferred to the non-volatile memory and will disappear, so when you turn on the ignition switch again, the mileage data that was previously stored in the non-volatile memory will be lost. The current mileage data is transferred to the counter. As a result, there was a problem in that the distance traveled from when the ignition switch was turned on until the battery was removed was not accumulated.

The present invention has been made in view of the above points, and in order to reliably prevent the cumulative distance of the odometer from falling out, the present invention detects engine rotation or vehicle running, and detects engine rotation and vehicle running until both engine rotation and running become zero. The cumulative traveling distance data of the counter is transferred to the nonvolatile memory only when the engine is rotated or the vehicle is running, and the traveling distance data stored in the nonvolatile memory is transferred to the counter only when the engine is rotated or the vehicle is running.

The present invention will be explained below with reference to FIG.

FIG. 2 is a block diagram showing one embodiment of the odometer according to the present invention, and reference numerals 1 to 5 in the figure indicate the same components as in FIG. 1. In this example, 7 is H when the vehicle is running.
(High) level and L when stopped.
A vehicle speed sensor that outputs a (Low) level; 8 an engine rotation sensor that outputs an H level when the engine is rotating and an L level when the engine is stopped; 9 a logic that takes the logical sum of the vehicle speed sensor 7 and the engine rotation sensor 8 It is a circuit.

In the above circuit, in the case of normal starting, the engine is first started, so the output of the engine rotation sensor 8 becomes H level, and therefore the output of the logic circuit 9 also becomes H level. As a result, the control device 5 transfers the contents of the non-volatile memory 4 to the counter 2.
On the other hand, in the case of so-called pushing, where the vehicle is pushed to start the engine due to a dead battery, the output of the vehicle speed sensor 7 becomes H level, and the contents of the non-volatile memory 4 are transferred to the counter 2 in the same way as described above. counter 2 starts accumulating from that value. In addition, during normal driving, both the vehicle speed sensor 7 and the engine rotation sensor 8 output the H level, and the logic circuit 9 also outputs the H level when the vehicle is stopped or when the engine is coasting while the engine is stopped. is at H level. Therefore, the operation of writing the contents of the counter 2 into the nonvolatile memory 4 is not performed. Since the output of the logic circuit 9 changes to L level for the first time when the vehicle is stopped and the engine is stopped, the control device 5 transfers the contents of the counter 2 to the non-volatile memory 4 and stores the cumulative mileage data up to that point. .

As established above, in the present invention, the contents of the non-volatile memory are transferred to the counter when the vehicle starts moving or the engine starts rotating, and the contents of the counter are transferred only when the vehicle stops and the engine also stops. Since the information is stored in non-volatile memory, it is possible to accumulate the distance traveled when the vehicle advances by pushing forward or by inertia with the engine stopped, and furthermore, it is possible to accumulate the distance traveled when the vehicle advances by pushing forward or by inertia with the engine stopped. Even if you leave the ignition switch on and remove the battery, the distance traveled up to that point is written to non-volatile memory when the vehicle and engine stop, so it will be necessary to turn on the ignition switch and then remove the battery. You can accumulate the distance traveled until the battery is removed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional electronic odometer for a vehicle, and FIG. 2 is a block diagram of an electronic odometer according to the present invention. DESCRIPTION OF SYMBOLS 1... Distance sensor, 2... Counter, 3... Display device, 4... Non-volatile memory, 5... Control device, 6... Ignition switch, 7... Engine rotation sensor, 8... Vehicle speed sensor, 9...Logic circuit.

Claims (1)

[Claims] 1. A distance sensor that outputs a pulse every time the vehicle travels a certain distance, a counter that counts the pulses and outputs travel distance data corresponding to the counted value, and calculates the travel distance based on the travel distance data from the counter. a mileage indicator that displays the mileage data; a non-volatile memory that stores the mileage data; and when the engine stops rotating and the vehicle stops running, the mileage data of the counter is transferred to and stored in the non-volatile memory. and control means for transmitting mileage data stored in the nonvolatile memory to the counter when the engine is rotated or the vehicle is running.