JP2002331856A - Racing boost meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boost meter of smooth motion of a meter indicator, inexpensive, and simple in use. SOLUTION: Smooth motion of a mechanical indicator is given to the meter in the sampling period by inserting the interpolated data calculated by a microcomputer using a mixed spline interpolation method in the boost pressure data for moving the meter indicator. A racing boost meter which is inexpensive, compact and simple in use is formed of a compact and inexpensive stepping motor and a two-stage reduction gear mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a racing boost meter for measuring and displaying a boost pressure of a vehicle.

[0002]

2. Description of the Related Art Conventionally, a method and an apparatus for digitally measuring and displaying a boost pressure in a vehicle equipped with a super suction device are disclosed in Japanese Patent Application Laid-Open No. 05-34479 and Japanese Patent Application No. 07-35018.
No. 3 (idling maintaining device), Japanese Patent Application No. 08-26
No. 2710 (intake pressure gauge with idling maintenance device).

A digital boost meter disclosed in the above-mentioned conventional publication converts a detected boost pressure value sampled at a predetermined cycle into digital data by A / D conversion and digitally displays or indicates the digital data. It is. In such a boost meter, since each indicated value by the sampling value is discrete, there is no correlation with the previous value.

Therefore, an instruction during a so-called sampling period between two adjacent sampling points merely moves linearly between sampling values P1, P2,... P8 as shown in FIG. Therefore, there is no such smoothness as the movement of a mechanical meter pointer. Therefore, it has been desired to realize a boost meter that gives a smooth indication like a mechanical meter pointer.

Conventionally, as a vehicular instrument for moving a pointer by using a stepping motor, a direct drive system in which a meter pointer and a stepping motor are directly connected is known. In this instrument, the indicating resolution of the meter pointer must be less than about 1 ° in order to make the movement of the meter pointer appear smooth, but the basic step angle of a stepping motor which is generally provided at a low cost is 7.5 ° or more. Since the angle is 15 °, an attempt is made to reduce the resolution of the operation angle by using an expensive micro-step drive circuit or the like.

Furthermore, the conventional boost meter is inconvenient to use in a vehicle because of its large size.

[0007]

As described above, in order to realize smooth data indication such as a mechanical meter pointer, the sampling cycle must be shortened. For this purpose, high-speed A / D conversion, arithmetic and data communication are required, and there is a problem that the cost is high. Therefore, a racing boost meter according to the present invention is to provide a boost meter in which the meter pointer moves smoothly as if it were a mechanical pointer without the need for high-speed A / D conversion, calculation and data communication. There is a problem of.

A second object of the present invention is to provide a boost meter which can make the resolution of the operating angle of the meter pointer sufficiently fine without using an expensive micro-step driving circuit or the like.

A third object of the present invention is to provide a simple boost meter which can be easily attached to a dashboard or the like in a vehicle by an adhesive means such as a tape.

[0010]

In order to solve the above first problem, a racing boost meter according to the present invention comprises:
A / D converter that samples the output of the boost pressure sensor at a predetermined cycle, and a mixed spline based on a plurality of past digital data obtained from the output of the A / D converter and a set boost pressure target value. Calculating means for calculating interpolation data during the sampling period using an interpolation method.

Since the expected position during the sampling period is given by the interpolation data created by the mixed spline interpolation method, the movement of the meter pointer between the sampling points becomes smooth rather than linear as in the prior art.

In order to solve the second problem, a stepping motor driven by the sampling data and the interpolation data output from the arithmetic means, a meter pointer driven by the stepping motor, and a stepping motor are provided. A speed reduction mechanism interposed between the meter pointer and the meter pointer;

According to a third aspect of the present invention, there is provided a racing boost meter according to the present invention, wherein the speed reduction mechanism connects a rotation shaft of the stepping motor and a first pulley by a first synchro belt. The first pulley and the second pulley are connected by a second synchro belt,
The meter pointer is fixed to the pulley.

As described above, the provision of the deceleration mechanism between the low-resolution, inexpensive small stepping motor and the meter pointer increases the indicator resolution of the meter pointer, so that a boost meter with good pointing performance can be provided at a low price. be able to. In addition, since the stepping motor and the two-stage speed reduction mechanism are compactly housed in a thin case, they can be easily attached to the dashboard of the vehicle, which is convenient for use.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a racing boost meter according to the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the racing boost meter according to the present invention includes a control unit 1, a boost pressure meter unit 2, a hydraulic meter unit 3, an oil temperature meter unit 4, and a communication line 5. ing.

The control unit 1 includes a boost pressure meter unit 2, a hydraulic meter unit 3, and an oil temperature meter unit 4.
And a communication line 5.

The control unit 1 includes a boost pressure sensor 11 for detecting a boost pressure and a hydraulic pressure sensor 1 for detecting a hydraulic pressure.
2, an oil temperature sensor 13 for detecting the oil temperature, and an A / D converter 14 for sampling and A / D converting the outputs from the boost pressure sensor 11, the oil pressure sensor 12, and the oil temperature sensor 13 at a predetermined sampling cycle. And the A / D converter 1
A microcomputer 15 for storing the boost pressure, oil pressure, and oil temperature data A / D converted by the A / D converter 4 in the EEPROM 16 and transmitting the respective sampling data to the meter units 2, 3, and 4 via the communication line 5; And an EEPROM 16 for storing the data.

The boost pressure meter unit 2 includes a meter pointer 21, a stepping motor 22 for mechanically moving the meter pointer 21, a drive circuit 23 for driving the stepping motor 22, and a communication line 5 from the microcomputer 15 of the control unit 1. The microcomputer 24 receives data related to the boost pressure via the microcomputer 24, performs an interpolation process based on the mixed spline interpolation method described later, and supplies drive data to the drive circuit 23, and inputs operation data to the microcomputer 24. And an operation switch 25 for

The hydraulic meter unit 3 includes a meter pointer 31.
A stepping motor 32 for mechanically moving the meter pointer 31, a driving circuit 33 for driving the stepping motor 32, and a communication line 5 from the microcomputer 15 of the control unit 1.
, And performs an interpolation process based on a mixed spline interpolation method described later, based on the received oil pressure data.
A microcomputer 34 for supplying drive data to the microcomputer 34, and an operation switch 35 for inputting operation data to the microcomputer 34.

The oil temperature meter unit 4 includes a meter pointer 41.
A stepping motor 42 for mechanically moving the meter pointer 41, a driving circuit 43 for driving the stepping motor 42, and a communication line 5 from the microcomputer 15 of the control unit 1.
, And performs an interpolation process based on the oil temperature data based on the mixed spline interpolation method to be described later.
The microcomputer 44 includes a microcomputer 44 for supplying drive data to the microcomputer 3 and an operation switch 45 for inputting operation data to the microcomputer 44.

The boost pressure sensor 11, the hydraulic pressure sensor 12,
The oil temperature sensor 13 is a pressure sensor that detects a boost pressure of a supercharger provided in an engine mounted on a vehicle, a pressure sensor that detects a hydraulic pressure, and a temperature sensor that detects an oil temperature. Type analog sensor.

Hereinafter, the boost pressure will be described for the sake of simplicity. An analog signal representing the boost pressure output from the boost pressure sensor 11 is input to an A / D converter 14 and is converted into a digital signal by the A / D converter 14 at a predetermined sampling interval.

The digital signals sampled by the A / D converter 14 are sequentially stored in a memory table provided in the EEPROM 16. The microcomputer 24 has an interpolation data creation program based on the mixed spline interpolation method, and executes this program upon request to calculate interpolation data to be interpolated during the sampling period.

FIG. 2 is a diagram for explaining a process of calculating interpolation data by the mixed spline interpolation method executed in the microcomputer 24. In FIG. 2, the horizontal axis x is time, and the vertical axis y is the magnitude of the boost pressure. Since the position of the meter pointer 21 of the boost pressure meter unit 2 is determined by the boost pressure y, y is hereinafter referred to as position data.

The RAM (not shown) of the microcomputer 24 stores past three time points (x0, x0) including the current position data y2.
1, x2) corresponding to sampling position data y0, y
1, y2 are stored. The microcomputer 24 uses the mixed spline interpolation method based on the four-point position data obtained by adding the three-point position data to the target position data y3 obtained by converting the latest sampling data sent via the communication line 5 into the position. The interpolation data is calculated as follows.

In the mixed spline interpolation method, an arbitrary x (-
Y for any x) between 1.0 and 2.0 is determined by the following equation: y = −x * (x−1) * (x−2) * y0 / 6 + (x +
1) * (x-1) * (x-2) * y1 / 2- (x + 1)
* X * (x-2) * y2 / 2 + (x + 1) * x * (x-
1) / 6 * y3

By substituting x = 1.5 into the above equation, the following equation is obtained. yt = (y0-5y1 + 15y2 + 5y3) / 16 yt is an x element x0, x of the points S0, S1, S2, S3
This is interpolation position data at x = 1.5 when 1, x2, and x3 are -1, 0, +1 and +2, respectively.

As described above, the current position S2 and the target position S
3 and an intermediate target position St is set, and position data yt of the intermediate target position is created. In this embodiment,
The point between the point S2 and the point S3 is divided into two.
By increasing the number of equal divisions into four, the smoothness of interpolation during the sampling period is increased.

The microcomputer 24 executes various programs such as a normal display function, a peak display function, a warning function, and a recording replay function in response to a request from the operation switch 25, in addition to the function of executing the mixed spline interpolation program.

The boost pressure meter unit 2 has a thickness of 17
mm, a stepping motor 22, a driving circuit 23, a microcomputer 24, and the like.
The operation switch 25 is arranged.

FIG. 3 is a top plan view of the boost pressure meter unit 2. Memory dial 2 illuminated by white LED
6 shows characters and scales. Further, the meter pointer 21 is rotated by using the center of the dial 26 as a rotation axis.
It is rotatably mounted on the.

When the dial 26 is black, the letters and scales and the meter pointer 21 are white and illuminate the letters. When the dial 26 is white, the letters and scales may be resin and the meter pointer 21 may be red or orange to illuminate the letters or the dial.

The operation switch 2 extends along the outer periphery of the dial 26.
5 push button switches (REC switch 25
a, MODE switch 25b, PEAK switch 25
c) is provided. The microcomputer 24 executes the various programs described above according to the combination of these push button switches and the pressing time.

When the REC switch 25a is pressed, for example, for less than three seconds, the microcomputer 24
A recording start request signal is transmitted to the The microcomputer 15 starts recording the boost pressure data output from the A / D converter 14 in the EEPROM 16 based on the recording start request signal. During recording, the green LED is turned on the REC switch 25a. The microcomputer 15 is an EEPROM
When the predetermined storage area of M16 is filled with the input data, the recording is stopped at that point.

When the REC switch 25a is pressed continuously for three seconds, the microcomputer 24
5, a recording transmission request signal is transmitted. The microcomputer 15 converts the boost pressure data into EEPR based on the recording transmission request signal.
Microcomputer 2 that reads from the top of the memory table of OM16
4 is transmitted.

The MODE switch 25b is a push button switch for switching the display mode. Each time the MODE switch 25b is pressed, the display mode is switched, and the number of times the yellow LED blinks changes.

There are four display modes: a real mode, a digital mode, an afterimage mode, and a peak hold mode. The yellow LED of the MODE switch 25b flashes once, twice, three times and four times, respectively. The real mode displays a change in the actual boost pressure. In the digital mode, the booster pressure is displayed by intermittently moving the meter pointer 21 (non-smooth movement). In the afterimage mode, for example, the peak value is held for 0.6 seconds and an afterimage is displayed. The peak hold mode updates and holds the maximum value. When the MODE switch 25b is pressed during the transmission of the reproduction data, the reproduction data is thinned out, for example, to one half and transmitted.

The PEAK switch 25c is a push button switch for instructing the microcomputer 15 of the control unit 1 to end reproduction and instruct the microcomputer 24 of the boost pressure meter unit 2 to display the peak value of the boost pressure. . When the PEAK switch 25c is pressed during playback, the playback ends.

In any of the above display modes, when the PEAK switch 25c is pressed, the maximum peak value from the time after the peak reset to the present is displayed. This value is stored in the EEPROM connected to the microcomputer 24 even after the ignition is turned off.
It is stored in a ROM (not shown). If the PEAK switch 25c is left, for example, for 3 seconds, the display mode shifts to the display mode before pressing. Further, the long press of the PEAK switch 25c resets the previous peak value.

The warning function is a function for turning on a red LED when the boost pressure exceeds a warning value. The mode is set to a warning value setting mode by pressing and holding the MODE switch 25b, and the REC switch 25a and the PEAK switch 25c are set.
By moving the meter pointer 21 to select a warning value, and then pressing the MODE switch 25b, the warning value is set and the display mode becomes the normal display mode.

FIGS. 4 and 5 show the top and side surfaces of a two-stage speed reduction mechanism for connecting the meter pointer 21 of the boost pressure meter unit 2 and the stepping motor 22. 6 and 7 show an AA cross section and a BB cross section of FIG.

As shown in FIG. 7, the stepping motor 2
In 2, its rotor remains rotatable, and its stator is fixed to the lower case 51 by columns 57 and 58. A pulley 52 is press-fitted and fixed to the output shaft of the stepping motor 22.

A pulley 54 is rotatably mounted on a shaft 53 fixed vertically to the lower case 51. Pulley 5
4 is rotationally driven by a pulley 52 via a synchro belt 55 at a reduction ratio of 16/50.

A pulley 57 is rotatably mounted on a shaft 56 fixed vertically to the lower case 51. Pulley 5
7 is rotationally driven by a pulley 54 via a synchro belt 58 at a reduction ratio of 16/50. The meter pointer 21 is fixed to the upper end of the pulley 57.

By the two-stage speed reduction mechanism, the rotation of the output shaft of the stepping motor 22 is rotated by 256/2 for one step.
The meter pointer 21 rotates by 500 steps. That is, the rotation of the small stepping motor 22 having a diameter of about 10 mm is transmitted to the meter pointer 21 at a reduced speed of about 1/10 through the two-stage reduction mechanism.

Since the two-stage speed reduction mechanism uses a synchro belt, there is no displacement due to slippage between the belt and the pulley. Further, as shown in FIG. 3, the pointing range of the meter pointer 21 is set to about 270 degrees, so that the meter pointer 21 does not hit the stepping motor 22 even if it rotates to the maximum pointing range.

Hereinafter, the mixed spline interpolation operation performed in the microcomputer 15 of the control unit 1 will be described with reference to FIGS.
This will be described in detail with reference to FIG. In these figures, the unit of the position data y is a step, and the meter pointer 21
Is moved from 50 steps to 20 steps.

First, the microcomputer 24 initializes the position data P1 = 50, P2 = 50, P2 as shown in FIG.
3 = 50 and P4 = 50 are stored in the RAM (not shown) of the microcomputer 24. The meter pointer 21 of the boost pressure meter unit 2 points to 50.

The microcomputer 24 converts the sampling data sent via the communication line 5 in the first sampling period into a position, and outputs the target position P to be moved next.
When y = 20 is obtained, yt = 41 is calculated as shown in FIG. 9 by substituting y0 = 50, y1 = 50, y2 = 50, and y3 = 20 into the programmed equation (yt).

The microcomputer 24 sends drive data to the drive circuit 23, and moves the meter pointer 21 to yt = 41 at a constant speed for half the sampling time. Subsequently, the meter pointer 21 is moved at a constant speed to y = 20 for half the sampling time.

In the second sampling period, the next target position P6 to be moved is obtained as P6 = 20. The microcomputer 24 calculates y0 = 50, y1 = 50, y2 = 20,
By substituting y3 = 20, as shown in FIG.
Calculate t = 13. The microcomputer 24 sends drive data to the drive circuit 23, and moves the meter pointer 21 to y = 13 at a constant speed for half the sampling time. Subsequently, the meter pointer 21 is moved at a constant speed to y = 20 for half the sampling time.

In the third sampling period, the next target position P7 to be moved is obtained. The microcomputer 24 calculates y0 = 50, y1 = 20, y2 = 20,
By substituting y3 = 20, as shown in FIG.
Calculate t = 22. The microcomputer 24 sends drive data to the drive circuit 23, and moves the meter pointer 21 to y = 22 at a constant speed for half the sampling time. Subsequently, the meter pointer 21 is moved at a constant speed to y = 20 for half the sampling time.

In the fourth sampling period, the next target position P8 to be moved is obtained. The microcomputer 24 calculates y0 = 20, y1 = 20, y2 = 20,
By substituting y3 = 20, as shown in FIG.
Calculate t = 20. Therefore, the microcomputer 24 keeps the meter pointer 21 at the current position because it is not necessary to move the meter pointer 21.

In this way, the meter pointer 21 moves from the position 50 to the position 20 along a locus as shown in FIG.
As shown in FIG. 13, an overshoot occurs in the trajectory between the position P5 and the position P6, an undershoot occurs in the trajectory between the position P6 and the position P7, and a static state occurs after the position P7. You can see that it is set.

As described above, in the boost pressure meter using the mixed spline interpolation method, since the movement of the meter pointer 21 has a correlation with the past movement, a slight overshoot occurs without stopping immediately after a large movement. Therefore, the movement is like a mechanical pointer, giving the user a sense of reality.

In order to eliminate the overshoot, when the next target position 20 to be moved is obtained in the second sampling cycle, it is determined that the target position is the same as or close to the previous position, and y0 = By replacing 20, y1 = 20, the position after the position P5 can be settled.

The operations of the hydraulic pressure meter unit 3 and the oil temperature meter unit 4 are the same as those of the boost pressure meter unit 2, and therefore will not be described.

[0059]

As described above, in the racing boost meter according to the present invention, the movement of the meter pointer can be made smooth like a mechanical meter by the data processing by the mixed spline interpolation method. It is easier to see than a meter and gives a sense of reality.

Further, the racing boost meter according to the present invention has a structure in which the rotation of the small and inexpensive stepping motor is reduced to about 1/10 of the meter pointer 21 by the two-stage reduction mechanism, so that the expensive micro-step drive is used. A fine pointing resolution can be obtained without using a circuit or the like.

Further, the racing boost meter according to the present invention uses an inexpensive stepping motor, so that the cost is reduced. In addition, since the small stepping motor and the two-stage speed reduction mechanism are compactly arranged in a thin case, they can be easily attached to a dashboard with a double-sided tape or the like, which is convenient for use.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a racing boost meter according to the present invention.

FIG. 2 is a graph showing a basic operation (mixed spline interpolation) of a microcomputer 15 in the embodiment.

FIG. 3 is a boost pressure meter unit 2 in the embodiment.
It is a sketch drawing which shows the surface of.

4 is a top view showing the inside of the boost pressure meter unit 2. FIG.

FIG. 5 is a side view showing the inside of the boost pressure meter unit 2.

FIG. 6 is a sectional view taken along line AA of FIG. 4;

FIG. 7 is a sectional view taken along the line BB of FIG. 4;

FIG. 8 is an explanatory diagram showing an example of the movement of the meter pointer 21 of the embodiment.

FIG. 9 is an explanatory diagram showing an example of the movement of the meter pointer 21 of the embodiment.

FIG. 10 is an explanatory diagram showing an example of a movement of the meter pointer 21 of the embodiment.

FIG. 11 is an explanatory diagram showing an example of a movement of the meter pointer 21 of the embodiment.

FIG. 12 is an explanatory diagram showing an example of the movement of the meter pointer 21 of the embodiment.

FIG. 13 is an explanatory diagram showing an example of the movement of the meter pointer 21 of the embodiment.

FIG. 14 is an explanatory diagram showing movement of a conventional meter.

[Explanation of symbols]

1: control unit 1, 2: boost pressure meter unit,
3: Oil pressure meter unit, 4: Oil temperature meter unit,
5: communication line, 11: boost pressure sensor, 12: oil pressure sensor, 13: oil temperature sensor, 14: A / D converter, 1
5: microcomputer, 16: EEPROM, 21: meter pointer, 22: stepping motor, 23: drive circuit, 2
4: microcomputer, 25: operation switch, 25a, 25b,
25c: push button switch, 26: dial, 51: lower case, 52, 54, 57: pulley, 53, 56: pulley shaft, 55, 58: synchro belt

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F041 EA02 EA04 EA07 EA08 2F055 AA22 BB14 CC60 DD20 EE40 FF05 GG03 2F075 AA01 BB08 EE15 EE16 EE17 EE18 FF05 FF07 FF10 3D044 BA03 BA21 BA28 BB01 BD01

Claims (3)

[Claims] An A / D converter for sampling an output of a boost pressure sensor at a predetermined cycle, a plurality of past digital data obtained from an output of the A / D converter, and a set boost pressure target value. Calculating means for calculating interpolation data during a sampling cycle using a mixed spline interpolation method, a motor driven by the sampling data output from the calculation means and the interpolation data, and a meter driven by the motor A racing boost meter comprising: a pointer. 2. A speed reduction mechanism is interposed between the motor and the meter pointer. The speed reduction mechanism connects a rotation shaft of the motor and a first pulley with a first synchro belt,
2. The racing boost meter according to claim 1, wherein the first pulley and the second pulley are connected by a second synchro belt, and the meter pointer is fixed to the second pulley. 3. The racing boost meter according to claim 1, wherein the motor is a stepping motor.