JP3786197B2 - Vehicle instrument and driving method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicular instrument and a driving method thereof, and in particular, a pulse signal emitted from a measurement target is counted, and a measurement amount corresponding to a running state of the vehicle is obtained by an ECU (engine control unit), and is obtained by the ECU. The present invention relates to a vehicular instrument that inputs the measured amount obtained through a serial transfer path and displays the travel information, and a driving method thereof.
[0002]
[Prior art]
As an instrument for vehicles, it has a display means consisting of a drive body such as a stepping motor or a cross coil type rotary magnet type ammeter, and a drive circuit for driving the display means based on a digital signal corresponding to a measurement amount, In some cases, the indicator mounted on the shaft end of the drive main body is displayed on a dial plate provided with a display index such as a scale or a numeral and provided on the drive unit, thereby displaying the running state of the vehicle.
[0003]
Such a vehicular instrument can be used for, for example, an automobile traveling speed meter, an engine tachometer, and also a fuel meter and a thermometer by A / D processing of a detection signal. For example, Patent Document 1 and Patent It is disclosed in Document 2 and various proposals have been made for practical use. Recently, serial communication in a vehicle instrument has progressed, and a digital signal corresponding to the running state of the vehicle is transmitted from the ECU mounted on the vehicle to the vehicle instrument via a serial transmission cable (serial transfer path). Thus, a driving device for operating the display means has been developed.
[0004]
[Patent Document 1]
JP 61-129575 A [Patent Document 2]
Japanese Patent Laid-Open No. 1-222312
[Problems to be solved by the invention]
A case will be described in which such a vehicular instrument is, for example, an analog display type speedometer that displays vehicle speed (hereinafter referred to as vehicle speed). The ECU temporarily inputs a pulse signal corresponding to a vehicle speed from a vehicle speed sensor (a sensor that generates a pulse signal in accordance with rotation of a vehicle wheel) mounted on the vehicle, and between effective edges of the pulse signal. Calculates the period of the pulse signal (rising from the rising edge of the pulse signal, or the pulse length from the falling edge to the falling edge), and outputs a digital signal corresponding to this period (hereinafter referred to as period data) to the speedometer via the serial transfer cable. To do. The speedometer converts the period data into speed data and displays the vehicle speed. However, since the generation of the pulse signal from the vehicle speed sensor is in a decreasing direction when the vehicle is decelerating, the ECU requires time for the period measurement, and therefore the period for transferring the period data becomes longer. Therefore, in the speedometer that is driven by inputting this cycle data, when the display means is driven in accordance with this transfer cycle, the movement of the pointer attached to the drive body becomes an intermittent motion, As a vehicular instrument, there is a problem that a smooth instruction operation cannot be obtained.
[0006]
Accordingly, the present invention focuses on the above-mentioned problems, and an object thereof is to provide a vehicle instrument and its driving method capable of preventing the intermittent movement of the display means and obtaining a smooth display operation as a vehicle instrument. It is.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention inputs a digital signal as vehicle information from a control unit mounted on a vehicle via a serial transfer path, and displays the state of the vehicle based on the digital signal by display means. A vehicle meter that inputs period data corresponding to a pulse length between effective edges as travel information of the vehicle via the serial transfer path as the digital signal, and when the period data is input, A first process for generating a latch timing for obtaining display data for operating display means, and a period of transfer of the period data is long, and there is no change from the period data that has been finally input, and the period data that has been last input a second process of generating a latch timing for obtaining display data for operating said display means when it reaches the considerable time, further Said final no change from the periodic data input, each reaching each time a plurality of steps a predetermined, and a third process of generating the latch timing for obtaining display data for operating the display means A latch timing generating means to be executed; a process for outputting each predetermined display data to the display means by the latch timing obtained by the first and second processes of the latch timing generating means ; Driving information conversion means for executing processing for outputting to the display means each display data that is gradually reduced by each latch timing generated by the above processing.
[0009]
Further, the present invention is a vehicle instrument driving method in which a digital signal which is vehicle information is input from a control unit mounted on a vehicle via a serial transfer path, and the state of the vehicle is displayed by display means based on the digital signal. The period data corresponding to the pulse length between effective edges, which is the traveling information of the vehicle, is input as the digital signal through the serial transfer path, and the display means is operated when the period data is input. The first processing for generating the timing for obtaining the display data is executed to output the predetermined display data to the display means, and the transfer period of the periodic data becomes longer and the change from the last input periodic data is changed. There is no timing for obtaining display data for operating the display means when the time corresponding to the last input cycle data is reached. When the second processing for generating the output is executed to output predetermined display data to the display means, and there is no change from the last input cycle data, and each time a predetermined number of stages are reached , Executing a third process for generating a timing for obtaining display data for operating the display means, and displaying the display data that gradually decreases with each latch timing generated by the third process. This is output by the display means.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the embodiment of the present invention, a speedometer will be described as an example of a vehicle instrument.
[0018]
FIG. 1 is a block diagram showing the overall configuration of the speedometer. The speedometer 1 is connected to an ECU unit (control unit) 3 via a serial transfer cable 2. The ECU unit 3 is connected to a vehicle meter comprising a combination meter including a speedometer, an engine tachometer, a water temperature meter, a fuel meter, and the like via a serial transfer cable 2, but in order to simplify the description. Only the speedometer 1 will be explained.
[0019]
The speedometer 1 inputs period data (digital signal) corresponding to the vehicle speed obtained by the ECU unit 3 and converts it into display data by a control means 11 comprising a microphone computer and a speed obtained by the control means 11 ( (Display) It is comprised from the drive main body (display means) 12 which operate | moves based on data.
[0020]
The control unit 11, CPU, ROM, is mainly composed of RAM及beauty output interface circuit, and the like, and controls the driving body 12 is converted into velocity data by later described processing the period data. The control means 11 has a latch timing generation function which is a latch timing generation means described in detail later for obtaining speed data from the cycle data, and a travel described in detail later for outputting the speed data to the drive body 12. It has a travel information conversion function as information conversion means.
[0021]
The drive main body 12 includes a stepping motor, a cross coil type rotary magnet type ammeter, and the like. The drive main body 12 is disposed behind the pointer 12a attached to the pointer shaft provided in the main body, and the scale, numbers, symbols, and the like. It is an analog display type instrument which obtains speed information by contrast reading with the dial 12b formed by printing. The drive main body 12 has a mechanism in which the pointer is driven when instruction angle data, which is speed data obtained by the control means 11, is input.
[0022]
The ECU unit 3 inputs a pulse signal from a vehicle speed sensor emitted according to the running state of the vehicle, counts between valid edges in the pulse signal by a clock signal of a predetermined cycle, and outputs the count result to cycle data (the valid data This is transferred to the speedometer 1 as digital data corresponding to the pulse length (time) between edges. The ECU unit 3 corresponds to the period data (pulse length (time) between the effective edges) of an ignition pulse signal (TA pulse signal) to a not-shown tachometer in addition to the transfer of the period data to the speedometer 1 described above. Digital data), or various signals such as a fuel gauge, a water temperature gauge, a blinker instruction, and a hazard instruction are transferred as serial data to various indicators (engine tachometer, etc.) via the serial transfer cable 2.
[0023]
Next, a method for driving the speedometer 1 will be described with reference to FIG.
[0024]
The control means 11 determines whether or not the period data transferred from the ECU unit 3 is input (step S1). The period data is input when the vehicle is performing normal driving such as acceleration or constant speed driving, and the period data is not input when the vehicle is in a decelerating state. .
[0025]
If the control means 11 determines that there is a change, it executes a reset process for writing “0” to the count value n of the internal counter used during the low-speed display process described later (step S2), and writes to the buffer for obtaining the speed average A first process for generating timing (hereinafter referred to as latch timing) is executed (step S3 to latch timing generation means).
[0026]
Next, the control means 11 obtains average cycle data in accordance with the generation of the latch timing, and substitutes the calculated average cycle data into a predetermined arithmetic expression to obtain speed data (step S4). It is converted into drivable instruction angle data and output to the drive main body 12 (step S5—travel information changing means). The above-described processing enables display processing during normal driving of the vehicle.
[0027]
Next, the low speed process at the time of deceleration of the vehicle in the control means 11 is demonstrated. When the control means 11 determines in step S1 that the periodic data transferred from the ECU unit 3 has not changed with respect to the previously input periodic data (determines that there is no change in the periodic data even after waiting for a predetermined time) ( In step S1), the count value n of the internal counter is "n + 1" (step S6).
[0028]
Then, the control means 11 determines whether or not the count value n of the internal counter is “1” (step S7), and “n = 1 (count value n = 1 for the first time)”. If it determines, the 2nd process which is a low speed process will be performed. The control means 11 determines whether or not a time corresponding to the final cycle data transferred from the ECU unit 3 and determined not to have changed has elapsed (step S8), and proceeds to step S3 after the time has elapsed. The latch timing is generated, the period data corresponding to the time is stored in the buffer in accordance with the generation of the latch timing, the average period data is obtained, and the calculated average period data is substituted into a predetermined arithmetic expression. Speed data (display data) is obtained (step S4), converted into command angle data that can be driven by the drive main body 12, and output to the drive main body 12 (step S5).
[0029]
When the cycle data does not change further in step S1, the control means 11 increments the counter value n of the internal counter to “n + 1” in step S6. When the control means 11 determines that “n = 1” is not satisfied by the determination of the count value n in step S7 (n = 2 in the second time), the internal control unit 11 executes the third process which is a low speed process. The count value n of the counter is compared with the predetermined number of repeated executions m as the third process (step S9). If not "n = m", the time of each time set in advance in a plurality of stages is compared. Of the first time elapses (step S10), and after the elapse of the first time, the process proceeds to step S3 to generate a latch timing, and the first timing is generated in accordance with the generation of the latch timing. Period data corresponding to one time is stored in the buffer to obtain average period data. Then, the calculated average cycle data is substituted into a predetermined arithmetic expression to obtain speed data (display data) (step S4), converted into command angle data that can be driven by the drive body 12, and output to the drive body 12 (step). S5).
[0030]
The third process in the control means 11 is repeatedly executed until the count value n of the internal counter and the repeated execution count m (for example, m = 6) match (“n = m”). If it is determined in step S1 that there is a change in the input periodic data before the end of the third process, the third process is immediately ended, and the normal first process is performed. Will be executed.
[0031]
In the time setting of the plurality of stages in the third process, the control unit 11 sets, for example, the first time to 120 ms, the second time to 180 ms, and the third time to 240 ms until the m-th time is reached. The time interval is set to increase every 60 ms.
[0032]
Further, as the speed data corresponding to the time setting of the plurality of stages, the first time (120 ms) is 11.8 km / h, the second time (180 ms) is 7.8 km / h, the third time The time (240 ms) is set so that the vehicle speed gradually decreases, such as 5.9 km / h.
[0033]
Even if the periodic data transferred from the ECU unit 3 is not input by the above-described second and third processes, pseudo multi-stage periodic data whose speed gradually decreases is stored in the buffer. Therefore, the operation of the pointer 12b of the drive main body 12 at the time of the vehicle low speed can be smoothly driven.
[0034]
The speedometer 1 and the driving method thereof input a digital signal which is vehicle information from an ECU unit 3 mounted on the vehicle via a serial transfer cable 2 and determines the speed (state) of the vehicle based on the digital signal. Displayed by the drive body 12, period data between effective edges as speed (running) information is input as the digital signal via the serial transfer path 2, and when the period data is input, the drive body 12 is displayed. A latch timing generation process for generating a latch timing for obtaining speed data to be operated is executed, the period data is converted into the speed data according to the timing obtained by the timing generation process, and the speed data is converted into the drive body 12. To output the travel information.
[0035]
Therefore, even if the data transferred from the ECU unit 3 is periodic data between valid edges of the pulse signal emitted from the vehicle speed sensor, the timing for the writing process to the buffer of the control means 11 can be generated, so that a good speed can be obtained. An indication can be obtained.
[0036]
Further, according to the speedometer 1 and its driving method, in the latch timing generation process, the transfer period of the periodic data becomes longer and there is no change from the last input period data, and the time corresponding to the last input period data is obtained. When the timing is reached, a timing for obtaining speed data for operating the drive body 12 is generated, and there is no change from the last inputted cycle data , and each time at predetermined times of a plurality of stages is reached. , Generating latch timing for obtaining the speed data, and controlling the drive main body 12 so that the speed data gradually decreases in accordance with the timing generated at each of the plurality of stages. Therefore, even if the vehicle is in a deceleration state in which the cycle of transfer of cycle data from the ECU unit 3 is long, the cycle data and speed data are simulated. Since the drive main body 12 can be generated and controlled based on a fine resolution, intermittent movement of the pointer 12a attached to the drive unit of the drive main body 12 is prevented, and smooth instruction operation as a vehicle instrument is achieved. Can be obtained.
[0037]
Although the speedometer 1 has been described as an example in the embodiment of the present invention, the present invention can also be applied to an engine tachometer.
[0039]
Further, in the embodiment of the present invention, an analog display type instrument has been described as an example, but the same effect can be obtained even when the present invention is applied to a digital display type instrument.
[0040]
【The invention's effect】
The present invention relates to a vehicle instrument that inputs a digital signal, which is vehicle information, from a control unit mounted on a vehicle via a serial transfer path, and displays the state of the vehicle by display means based on the digital signal, and a drive thereof With respect to the method, it is possible to prevent intermittent movement of the display means and to obtain a smooth display operation as a vehicle instrument.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention.
FIG. 2 is a diagram showing a driving method according to the embodiment.
[Explanation of symbols]
1 Speedometer (vehicle instrument)
11 Control means 12 Drive body (display means)
12a Pointer 12b Dial 2 Serial transfer cable (serial transfer path)
3 ECU unit (control unit)

Claims (2)

A vehicle instrument for inputting a digital signal which is vehicle information from a control unit mounted on a vehicle via a serial transfer path, and displaying a state of the vehicle based on the digital signal by a display means,
Periodic data corresponding to a pulse length between effective edges, which is travel information of the vehicle, is input as the digital signal through the serial transfer path, and display data for operating the display means when the periodic data is input. A first process for generating a latch timing to obtain, and when the transfer period of the periodic data is long and there is no change from the last input periodic data, and the time corresponding to the last input periodic data is reached. The second process for generating the latch timing for obtaining the display data for operating the display means, and further , every time when the predetermined time is reached without any change from the last inputted cycle data Latch timing generation means for executing a third process for generating latch timing for obtaining display data for operating the display means ,
The latch timing generation unit executes a process of outputting predetermined display data to the display unit according to the latch timing obtained by the first and second processes, and also generates the respective display data generated by the third process. Travel information conversion means for executing a process of outputting each display data gradually decreasing according to the latch timing to the display means;
An instrument for a vehicle, comprising: A vehicle instrument driving method for inputting a digital signal which is vehicle information from a control unit mounted on a vehicle via a serial transfer path, and displaying a state of the vehicle by a display unit based on the digital signal,
Display for operating the display means when period data corresponding to a pulse length between effective edges, which is travel information of the vehicle, is input as the digital signal via the serial transfer path, and the period data is input. Performing a first process for generating a timing for obtaining data to output predetermined display data to the display means;
In order to obtain display data for operating the display means when the transfer period of the periodic data is long and there is no change from the last input periodic data and the time corresponding to the final input periodic data is reached. A second process for generating timing is executed to output predetermined display data to the display means;
Further, a third process for generating a timing for obtaining display data for operating the display means each time a predetermined time of a plurality of stages is reached without any change from the last inputted cycle data. A vehicle instrument driving method characterized in that, when executed, the display means outputs display data that gradually decreases according to each latch timing generated by the third processing .

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