Measuring unit for vehicle

Abstract

To provide a measuring unit for a vehicle which can precisely display the voltage of a main power source on the basis of the electric load of a measuring unit for a vehicle.SOLUTION: A measuring unit 1 for a vehicle is supplied with a main power source for the vehicle through a protection fuse 24, and measures and displays the voltage of the main power source. The measuring unit includes: a display unit 34; a light source element 351 for illuminating the display unit 34; a control unit 36 for controlling the display unit 34 and a light source element 351; and a stabilization power source circuit 31 for receiving the input of the main power source and supplying the power source to the display unit 34 and the control unit 36. The control unit 36 measures the voltage of the main power source through the protective fuse 24, corrects the measured voltage of the main power source on the basis of the electric load of the power source element 351, and displays the measured voltage in the display unit 34.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to vehicle instruments. [Background technology]

[0002] In addition to vehicle instruments that are installed in a vehicle, Patent Document 1 and other documents disclose vehicle instruments that can be retrofitted to display various vehicle information in detail. These retrofitted vehicle instruments are also called after-meters, and include a variety of instruments such as a water temperature gauge that displays the temperature of the coolant for a water-cooled engine, an oil temperature gauge that displays the temperature of the engine oil, and a voltmeter that displays the voltage (battery voltage) of the vehicle's battery (main power source). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-169597 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional vehicle gauges that display battery voltage do not take into consideration the electrical load of the vehicle gauge itself, and there is room for improvement in the accuracy of the displayed voltage.

[0005] Therefore, an object of the present disclosure is to provide a vehicle instrument that can accurately display the voltage of a main power supply by taking into account the electrical load of the vehicle instrument itself. [Means for solving the problem]

[0006] In one aspect, the following solution is provided. A vehicle instrument is supplied with a vehicle's main power supply through a protective fuse, and measures and displays the voltage of the main power supply, comprising: a display unit, a light source element that illuminates the display unit, a control unit that controls the display unit and the light source element, and a stabilized power supply circuit that receives the main power supply and supplies power to the display unit and the control unit, wherein the control unit measures the voltage of the main power supply through the protective fuse, corrects the measured voltage of the main power supply based on the electrical load of the light source element, and displays the corrected voltage on the display unit. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a vehicle meter that can accurately display the voltage of a main power supply by taking into account the electrical load of the vehicle meter itself. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a configuration of a vehicle instrument; [Diagram 2] 1A and 1B are diagrams showing examples of correction tables, in which FIG. 1A is a correction table applied when the electrical load is low, and FIG. 1B is a correction table applied when the electrical load is high. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings.

[0010] The vehicle instrument 1 shown in Fig. 1 is an aftermarket meter that is attached to a vehicle and is used as a voltmeter that measures and displays the voltage of the vehicle's main power supply. The vehicle instrument 1 includes a dedicated harness 2 and an instrument body 3. The instrument body 3 operates as a voltmeter by being connected to the vehicle via the dedicated harness 2.

[0011] The dedicated harness 2 includes a main power supply line 21, a ground line 22, an illumination power supply line 23, and a protective fuse 24.

[0012] The main power supply line 21 connects the main power supply connection terminal T1 of the meter main body 3 to the main power supply of the vehicle. The main power supply of the vehicle to which the meter main body 3 can be connected is, for example, an ignition power supply, an accessory power supply, a battery power supply, etc., and the ignition power supply is particularly suitable. In this case, the meter main body 3 can be started / shut down depending on whether the ignition switch is ON / OFF.

[0013] The ground line 22 connects the ground connection terminal T2 of the instrument body 3 to the vehicle ground GND.

[0014] The illumination power supply line 23 connects the illumination power supply connection terminal T3 of the instrument body 3 to the illumination power supply of the vehicle. The illumination power supply is a power supply system whose voltage varies depending on the state of the vehicle's lights (e.g., small lights), and is used, for example, to switch between day mode and night mode of the lighting equipment.

[0015] The protective fuse 24 is disposed in the main power supply line 21 and cuts off the main power supply line 21 in response to an abnormal current, thereby making it possible to prevent a fire accident caused by a breakdown of the meter body 3 or the like.

[0016] The instrument main body 3 includes a stabilized power supply circuit 31, a voltage dividing circuit 32, an input circuit 33, a display unit , an illumination unit 35, and a control unit .

[0017] The stabilized power supply circuit 31 is connected to the main power supply via the protective fuse 24, and stabilizes the fluctuating voltage of the main power supply to the control unit 36, etc. The stabilized power supply circuit 31 is configured using, for example, a switching power supply circuit.

[0018] The voltage divider circuit 32 is connected to the main power supply via the protective fuse 24, and transforms the voltage of the main power supply (maximum 12V) to the input range (0 to 5V) of the A / D port of the control unit 36 ​​and inputs it to the A / D port of the control unit 36.

[0019] The input circuit 33 converts (binarizes) the voltage of the illumination power supply into an illumination signal (ON / OFF signal indicating day / night) and inputs the signal to the control unit 36 ​​.

[0020] Display unit 34 displays the measured voltage of the main power supply. For example, when the voltage of the main power supply is indicated by a pointer, a dial having an index scale or an analog meter having a motor for moving a pointer is applied. When the voltage of the main power supply is indicated by an image, a liquid crystal display or the like is applied.

[0021] The illumination unit 35 includes a light source element 351 such as an LED that illuminates the display unit 34. For example, when the display unit 34 is an analog meter, the light source element 351 is disposed on the back of the dial, and the indicator scale is illuminated in response to the illumination of the light source element 351.

[0022] The light source element 351 is connected to the main power supply via the protective fuse 24, and is turned on by the current supplied from the main power supply. The illumination unit 35 is also provided with a transistor 352 that switches the lighting state of the light source element 351. The transistor 352 intermittently drives the light source element 351 based on a PWM signal output from the control unit 36, and lights up the light source element 351 at a brightness according to the duty ratio of the PWM signal.

[0023] The control unit 36 ​​is configured using, for example, a microcontroller, and functions as a day / night determination means, a lighting control means, a voltage measurement means, a voltage correction means, a voltage display means, and the like, according to a program written in the ROM.

[0024] The day / night determining means determines whether the mode is the day mode or the night mode based on the illumination signal input from the input circuit 33.

[0025] The illumination control means lights up the light source element 351 at a predetermined luminance based on the result of the determination by the day / night determination means. For example, in the night mode, the light source element 351 is turned on at a dark first luminance, and in the day mode, the light source element 351 is turned on at a bright second luminance.

[0026] The voltage measuring means measures the voltage of the main power supply from the voltage value input via the voltage dividing circuit 32. The voltage measured here includes an error due to the electrical load of the vehicle instrument 1. The electrical load of the vehicle instrument 1 includes the electrical load of the dedicated harness 2 and the electrical load of the instrument body 3. In particular, the protective fuse 24, which is the electrical load of the dedicated harness 2, and the light source element 351, which is the electrical load of the instrument body 3, have a large influence on the above error.

[0027] The voltage correction means corrects the measured voltage of the main power supply based on the electrical load of the vehicle instrument 1. Specifically, the voltage correction means corrects the error caused by the protective fuse 24 and the error caused by the light source element 351.

[0028] Since the dedicated harness 2 is an in-house product, the resistance value of the built-in protective fuse 24 can be known in advance. Furthermore, in the instrument body 3, the current value flowing through the light source element 351 in the night mode and the current value flowing through the light source element 351 in the day mode can be known in advance by measurement. Based on this advance information, a correction table for correcting errors due to the protective fuse 24 and the light source element 351 is created, and the created correction table is stored in advance in the control unit 36. As a result, the voltage correction means corrects the measured voltage value in the upward direction according to the correction table, and an accurate voltage value from which errors due to the protective fuse 24 and the light source element 351 have been removed can be obtained.

[0029] 2 shows examples of correction tables, where (a) is a correction table applied when the electrical load is low, and (b) is a correction table applied when the electrical load is high. In other words, when it is determined that the illumination power supply is in the night mode, the measured voltage is corrected using the correction table for low load shown in (a) of FIG. 2 in order to illuminate the light source element 351 with a dark first luminance. On the other hand, when it is determined that the illumination power supply is in the day mode, the measured voltage is corrected using the correction table for high load shown in (b) of FIG. 2 in order to illuminate the light source element 351 with a bright second luminance.

[0030] The voltage display means displays the corrected voltage of the main power supply on the display unit 34.

[0031] The above is a description of the embodiment of the vehicle instrument 1 of the present disclosure.

[0032] The vehicle instrument 1 of the present disclosure is supplied with the main power supply of the vehicle through the protective fuse 24, and measures and displays the voltage of the main power supply. The vehicle instrument 1 includes a display unit 34, a light source element 351 that illuminates the display unit 34, a control unit 36 ​​that controls the display unit 34 and the light source element 351, and a stabilized power supply circuit 31 that receives the main power supply and supplies power to the display unit 34 and the control unit 36. The control unit 36 ​​measures the voltage of the main power supply through the protective fuse 24, corrects the measured voltage of the main power supply based on the electrical load of the light source element 351, and displays it on the display unit 34. This makes it possible to remove errors caused by the electrical load of the vehicle instrument 1 and display the voltage of the main power supply with high accuracy.

[0033] In addition, the measured voltage is corrected based on the current value flowing through the light source element 351 and the resistance value of the protective fuse 24, so that the electrical load of the vehicle instrument 1 can be accurately grasped and the measured voltage can be corrected with high precision.

[0034] Furthermore, since the control unit 36 ​​determines the value of the current flowing through the light source element 351 based on the illumination power supply of the vehicle, the circuit configuration can be simplified compared to the case where the value of the current flowing through the light source element 351 is actually measured.

[0035] Although the embodiments have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the claims. In addition, it is also possible to combine all or a plurality of the components of the above-described embodiments. [Explanation of symbols]

[0036] 1 Vehicle Instruments 2 Dedicated harness 21 Main power line 22 Grand Line 23 Illumination power line 24 Protective fuse 3. Instrument body 31 Stabilized power supply circuit 32 Voltage divider circuit 33 Input circuit 34 Display section 35 Lighting Department 351 Light source element 352 Transistor 36 Control Unit T1 Main power connection terminal T2 Ground connection terminal T3 Illumination power connection terminal

Claims

1. A vehicle meter that is supplied with a main power supply of a vehicle through a protective fuse and measures and displays a voltage of the main power supply, A display unit; A light source element that illuminates the display unit; A control unit that controls the display unit and the light source element; a stabilized power supply circuit that receives the main power supply and supplies power to the display unit and the control unit, The control unit measures a voltage of the main power supply through the protection fuse, corrects the measured voltage of the main power supply based on an electrical load of the light source element, and displays the corrected voltage on the display unit. Vehicle instruments.

2. The correction is performed based on a current value flowing through the light source element and a resistance value of the protection fuse.

2. The vehicle instrument according to claim 1.

3. The control unit determines a current value flowing through the light source element based on an illumination power source of the vehicle.

3. The vehicle instrument according to claim 2.

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