JP2001174304A - Sensor with built-in arithmetic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor with a built-in arithmetic device capable of setting adjustment data taking the error appearing in an adjusting process into consideration when setting a correction constant at the time of adjustment and capable of optimizing the set correction constant with the numeral arithmetic means of the sensor itself. SOLUTION: Correction data from the outside such as a PC(personal computer) are set in a data memory means 400, and the error of the correction data set in the memory means 400 is adjusted only once at a flow point by an adjustment data correcting means 350 via a communication means 330. The flow point adjusted for the error is set in the memory means 400 as a new flow point. The error of the flow calculated by the numeral arithmetic means 300 is estimated from the relation between the flow point of the memory means 400 and the error, and whether the error is in a tolerance or not is judged. If the error is in the tolerance, the adjustment data are set in the memory means 400. If the error is judged to be outside the tolerance, the set flow data are corrected again based on the error and set in the memory means 400 as new adjustment data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for an automobile, and more particularly, to a sensor having a numerical operation means and a means for correcting a measurement error. The present invention relates to a heating resistor type air flow sensor suitable for measuring the temperature.

[0002]

2. Description of the Related Art In a conventional sensor for detecting, for example, an analog signal for an automobile, especially in a heating resistor type air flow measuring device, a driving circuit using an operational amplifier or the like is used so that the temperature of a heating wire becomes a predetermined temperature. The current flowing through the heating wire or the like is controlled, and the air flow rate is measured using the current flowing through the heating wire or the like.

Here, the operational amplifier used for the driving circuit is:
Each of the resistors has an offset, and the resistors used in the drive circuit also have variations in resistance value. Therefore, in the conventional heating resistor type air flow measuring device, there is a measurement error in each heating resistor type air flow measuring device due to the offset and the variation of the resistance value.

Therefore, at the time of shipment of the heating resistor type air flow measuring device, the characteristics are checked for each unit and the output is adjusted so as to be within the specification range.

As an adjustment method at the time of shipment, conventionally,
Resistance trimming had been performed. By this resistance trimming, the zero point and the span of the output of the heating resistor type air flow measuring device are adjusted so as to be within the specification range. However, the resistance trimming is not easy to perform an adjustment operation and includes an adjustment error.

Therefore, for example, US Pat. No. 4,669,
As described in the specification of Japanese Patent No. 052, electronic trimming for performing multi-point correction using digital data by using numerical calculation means is known.

Japanese Patent Application Laid-Open Nos. Hei 11-14418, Hei 10-19625, and Hei 9-273951 disclose an air flow measuring device that corrects a measurement error by an inverse conversion process or the like. Gazette, JP-A-5-288
113 and JP-A-11-271126.

[0008]

Incidentally, in the adjustment by multipoint correction in the air flow measurement device described in the above-mentioned US Pat. No. 4,669,052, it is important to set a correction constant corresponding to resistance trimming. Become.

In a normal adjustment operation, an output error is verified and a correction constant is set so as to minimize the error. As an example of the method, by measuring the error at the flow point,
A constant for canceling the error was set in accordance with the flow point.

However, in the actual measurement, since there is a case where the measurement is performed at a flow point different from the flow point set in the adjustment work, the set constant corrects the error with high accuracy due to the deviation of the flow point. It was difficult.

Also, in the technique of correcting a measurement error by an inverse conversion process or the like, an error occurs in data for correction, and it has been difficult to perform high-precision correction.

Therefore, once the correction data is set,
It is conceivable to set a new correction data from outside by feeding back the correction data to an optimum value as compared with the true value.

However, such a feedback operation is complicated and complicates the manufacturing process of the sensor.

An object of the present invention is to provide a sensor having a numerical operation means for performing multipoint correction of two or more points by digital data for adjustment, and an error which appears in an adjustment step when a correction constant is set at the time of adjustment. An object of the present invention is to realize a sensor with a built-in arithmetic device that can set adjustment data in consideration of the minute and that can optimize a set correction constant by a numerical operation unit of the sensor itself.

[0015]

To achieve the above object, the present invention is configured as follows. (1) A sensor for measuring an object to be measured, which is a sensor with a built-in arithmetic device and has a numerical operation means for correcting a measurement error, and an adjustment data correction means for correcting a correction constant for correcting the measurement error of the sensor. Is provided.

(2) In a sensor for measuring an object to be measured, which is a sensor with a built-in arithmetic unit having numerical calculation means for correcting a measurement error, a correction constant for correcting the measurement error of the sensor is provided by an external signal. Adjustment data correction means for performing internal adjustment based on the data.

(3) In a sensor for measuring an object to be measured, which is a sensor with a built-in arithmetic unit and having a numerical operation means for correcting a measurement error, a correction constant for correcting the measurement error of the sensor is replaced by the numerical operation means. An adjustment data correction unit for resetting to an optimum value based on the error amount calculated by itself is provided.

(4) An air flow sensor for detecting an intake air flow rate using a heating resistor, a means for converting an output signal of the air flow sensor into a digital signal, and a numerical calculation means for correcting a flow rate error And an adjustment data correction means for correcting a correction constant for correcting the flow rate error.

(5) An air flow sensor for detecting an intake air flow rate using a heating resistor, means for converting an output signal of the air flow sensor into a digital signal, and numerical value calculation means for correcting a flow rate error In the heating resistor type air flow rate measuring device having the above, an adjustment data correcting means for performing an internal adjustment of a correction constant for correcting the flow rate error based on an external signal.

(6) An air flow sensor for detecting an intake air flow rate using a heating resistor, means for converting an output signal of the air flow sensor into a digital signal, and a numerical operation means for correcting a flow rate error In the heating resistor type air flow rate measuring device having the above, an adjustment data correcting means for resetting a correction constant for correcting the flow rate error to an optimum value based on the error amount calculated by the numerical value calculating means itself is provided.

(7) An air flow sensor for detecting an intake air flow rate using a heating resistor, a means for converting an output signal of the air flow sensor into a digital signal, and a numerical calculation means for correcting a flow rate error In the heating resistor type air flow rate measuring device having the above, the correction constant for correcting the flow rate error is an error map composed of a flow rate signal and error data.

(8) An air flow sensor for detecting an intake air flow rate using a heating resistor, a means for converting an output signal of the air flow sensor into a digital signal, and a numerical calculation means for correcting a flow rate error In the heating resistor type air flow measuring device having the above, an error is calculated from the flow signal input from the outside and the flow converted from the output of the air flow sensor by the numerical calculation means, and the error is calculated from the output of the air flow sensor. An error map for setting a correction constant for correcting the flow rate error based on the flow rate and the obtained error is provided.

(9) An air flow sensor for detecting an intake air flow rate using a heating resistor, a means for converting an output signal of the air flow sensor into a digital signal, and a numerical operation means for correcting a flow error. In the heating resistor type air flow rate measuring device having the above, the error is calculated from the flow rate signal input from the outside and the flow rate converted from the output of the air flow rate sensor by the numerical calculation means, and the error is calculated from the output of the air flow rate sensor. An error map for setting a correction constant for correcting the flow rate error by the obtained flow rate and the obtained error is provided, and the numerical operation means again uses the flow rate converted using the error map and the input flow rate signal, Reset the error map.

(10) Preferably, in the above (7) to (9), the error map is stored in data storage means.

(11) In a sensor for measuring an object to be measured, which is a sensor with a built-in arithmetic device having numerical calculation means for correcting a measurement error, data set as a correction constant for correcting the error is subjected to linear interpolation. By setting the denominator items at equal intervals when performing a map search, the linear interpolation calculation at the time of data search is simplified.

(12) In a processing program recording medium for storing a processing program for correcting a measurement error correction constant of a sensor with a built-in arithmetic unit having a numerical calculation means for correcting a measurement error, a correction constant for correcting the measurement error of the sensor is stored. Internal adjustment based on a signal from the outside, stored in the storage means, using the stored correction constant, correct the measured value, compare the corrected value with the true value, A processing program for adjusting the correction constant until the difference between the value obtained by the correction and the true value falls within a predetermined range, and storing the obtained correction constant as a new correction constant in the storage means is stored.

(13) An air flow sensor for detecting an intake air flow rate using a heating resistor, a means for converting an output signal of the air flow sensor into a digital signal, and a numerical calculation means for correcting a flow rate error In a processing program recording medium for storing a processing program for correcting a measurement error correction constant of the heating resistor type air flow measuring device having a correction constant for correcting a measurement error of the air flow sensor based on an external signal. Internally adjusted and stored in the storage means, the measured air flow value is corrected using the stored correction constant, the corrected air flow value is compared with a true value, and the corrected air flow value is corrected. A processing program for adjusting the correction constant until the difference between the obtained value and the true value falls within a predetermined range, and storing the obtained correction constant as a new correction constant in the storage means is stored.

By inputting the adjustment data to be mapped in the adjustment step, the numerical calculation means has a means for self-correcting the error and resetting the correction constant, which is the adjustment data, to an optimum value. It is possible to optimize.

In particular, an air flow sensor for detecting an intake air flow rate of an internal combustion engine by using a heating resistor, an output signal of the air flow sensor is digitally converted into an air flow signal, and a flow error is digitally corrected. In a heating resistor type air flow rate measuring device having a numerical calculation means for performing the calculation, by inputting a flow point and an error in the adjustment step, the numerical calculation means self-corrects the error and resets the correction constant optimally. Providing the means makes it possible to optimize the correction constant.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sensor for detecting an analog signal is affected by variations in component accuracy depending on a circuit configuration for detecting the signal. Therefore, it is necessary to adjust the products individually to secure the accuracy.

As one of sensors for detecting an analog signal for an automobile, for example, there is a heating resistor type air flow measuring device. Hereinafter, the present invention will be described with the heating resistor type air flow measuring device as one embodiment.

First, FIG. 12 shows an air flow device having no function of the present invention as a comparative example of FIGS. 6 and 7 and the present invention.
The configuration of the heating resistor type air flow measuring device according to one embodiment of the present invention will be described with reference to FIG.

First, the configuration of the air flow sensor circuit 100 of the heating resistor type air flow measuring device according to one embodiment of the present invention will be described with reference to FIG. In FIG.
The air flow sensor circuit 100 includes a heating resistor RH arranged in the intake pipe TB for measuring the intake air flow rate, a temperature sensitive resistor RC for compensating the intake air temperature, and a drive circuit 110. ing.

The driving circuit 110 is roughly composed of a bridge circuit and a feedback circuit. A bridge circuit is formed by the heating resistor RH, the temperature-sensitive resistor RC, and the resistors R1 and R2.

By inputting the voltage between both ends of the resistor R1 and the voltage between both ends of the resistor R2 to the operational amplifier OP1, the operational amplifier OP1 applies a constant temperature between the heating resistor RH and the temperature-sensitive resistor RC while applying feedback. The feedback circuit is configured to supply the heating current Ih to the heating resistor RH so as to maintain the difference.

Here, when the flow velocity of the air flowing through the intake pipe TB is high, the amount of heat taken from the heating resistor RH increases, and the heating current Ih flows more. In addition, the intake pipe TB
When the flow velocity of the air flowing through the inside is low, the heating resistor RH
Since the amount of heat deprived from the heat is small, the heating current Ih is also small.

That is, the heating current Ih is proportional to the flow rate of the air flowing through the intake pipe TB.

Therefore, the heating current Ih is detected as a voltage across the resistor R1, and an air flow sensor voltage (AFS voltage) a
Output as VtAfs. Conventionally, this signal was directly output to the ECU which is the engine control device. However, in one embodiment of the present invention, this signal is once taken in by the A / D conversion means 200 shown in FIG. After the correction processing is performed by the calculation means 300, the correction signal is output as the air flow rate correction signal VtQa.

The point that this correction process is performed is different from the conventional air flow measuring device (AFS), and is called I-AFS (intelligent AFS) to distinguish it from the conventional type.

Next, the overall configuration and main operation of the heating resistor type air flow measuring device according to one embodiment of the present invention will be described with reference to FIGS.

FIG. 6 is a partial cross-sectional view showing a state in which the heating resistor type air flow measuring device according to one embodiment of the present invention is attached to an intake pipe. As shown in FIG. 6, a hole is formed in a wall surface of a main air component constituting the intake pipe TB,
The heating resistor type air flow measuring device I-AFS is provided with an intake pipe T
B is inserted from the outside of the wall through a hole in the wall surface, and is fixed to the wall surface of the intake pipe TB with screws or the like so as to maintain mechanical strength.

This heating resistor type air flow measuring device IA
As shown in the system configuration diagram of FIG. 12, the A / D conversion unit 200 and the numerical calculation unit 3
There are a housing member HOS containing a circuit board CB that constitutes the air flow sensor circuit 100 including the drive circuit 110 shown in FIG. 7, and a sub air passage member BP formed of a non-conductive member.

A heating resistor RH for detecting the air flow rate and a temperature-sensitive resistor RC for compensating the intake air temperature are arranged in the sub air passage component BP.

The heating resistor RH and the temperature sensing resistor RC are electrically connected to the circuit board CB via a support HCW made of a conductive member. Housing HO
S, circuit board CB, auxiliary air passage BP, heating resistor RH,
The temperature-sensitive resistor RC and the like are configured as an integrated module as a heating resistor type air flow measuring device I-AFS.

The air flow sensor circuit 100 includes an intake pipe TB
, And outputs an air flow sensor voltage (AFS voltage: aVtAfs). The AFS voltage output from the air flow sensor circuit 100 is converted into a digital signal by the A / D converter 200 and input to the numerical calculator 300.

As shown in FIG. 12, the numerical calculation means 300 may include the A / D means 200, or may be configured independently. A signal from the air flow sensor circuit 100 is input to the A / D conversion means 200, and the result corrected by the correction means 310 based on the data is used as an air flow correction signal (AFS voltage correction value: VtQa).
It outputs to ECU which is an engine control unit.

At this time, the ECU side considers that the analog signal is almost always received as before,
On the AFS side, after performing the correction processing, the corrected signal (QaRef), which has been handled by digital data, is output to the ECU via the D / A conversion means 500 for converting the signal (QaRef) into an analog signal (VtQa).

Before the correction by the correction means, the signal input to the A / D conversion means 200 is converted from analog voltage values to digital data. Based on the digital data, the data is converted into flow rate data by the flow rate conversion means 320 for correction in the numerical value calculation means 300.

According to the method, as shown in FIGS. 8A and 8B, based on data set in advance as a map, the interval between data is expressed by an equation shown in FIG. 8C. From the AFS voltage (VtAfs) from the A / D conversion means 200, the air flow rate data (Q
aTbl). In the example shown in FIG. 8, the map data is 64 points, but may be a number other than 64 points.
It is not limited to 64 points.

The interval (ΔVtAfs) of the data set as the map is set as a fixed value at regular intervals, but by setting in this manner, ΔVtAfs can be treated as a constant. When calculating dY in the formula shown in (1), division is not required, and the calculation can be simplified.

The data QaTbl converted into the flow rate includes an error due to a difference between individual characteristics. As described above, the factor is caused by the variation of the characteristic and the resistance value of the operational amplifier OP1 shown in FIG. Conventionally, the individual characteristics are adjusted by resistance trimming by resistance trimming. However, in the I-AFS, data capable of checking the characteristics of each unit and correcting an error is stored in the data storage unit 400 as adjustment data. The configuration is such that it can be stored.

At the time of correction, errors due to individual characteristic differences are corrected by the adjustment data stored in the data storage means 400. The adjustment data for correcting the flow rate error is set in the data storage means 400 as an error map, as shown in FIG.

The data stored in the data storage means 400 is configured such that data can be set from the outside by a communication means 330 of the I-AFS from an external PC (personal computer) or the like. Can be adjusted from.

That is, during the shipping test of the air flow sensor, the adjustment data is set individually for each unit,
Adjustment or digital trimming. In one embodiment of the present invention, the data tabulated as the adjustment data is multi-point data of ten points, and is composed of a flow point, a gradient at that point, and an intercept.

As shown in FIG. 9C, from the input flow rate data QaTb1, linear interpolation (the slope a (n) and the intercept b (n) from the data q (n) and q (n-1)) are performed. Is calculated) to calculate the flow rate error CmQa. An algorithm is used to calculate a corrected flow rate value QaRef from the calculated error CmQa and the flow rate data (before correction) QaTbl.

The gradient set in the adjustment data is 16-bit data in which the most significant bit is treated as a sign bit. 0% is represented by H'8000 (hexadecimal number), and is defined so that it can be expressed at a maximum of ± 25%.

That is, H'0000 (hexadecimal) is-
25%, and H'FFFF (hexadecimal) is defined as + 25%. The intercept is also 16-bit data, with a minimum value of -25% (H'0000) and a maximum value of + 25% (H'F
FFF) and the midpoint is defined as 0% (H'8000). Data (flow rate error CmQa in this case) is calculated by linear interpolation between the set data.

In the linear interpolation, as shown in FIG.
From the value of the flow rate data QaTbl, the range in the table shown in FIG. 9A is searched (q (n) in FIG. 9).
And q (n-1)), and the flow rate error CmQa is calculated from the data between the two defined points. here,
a (n) represents a gradient defined by data n (q (n)), and b (n) represents an intercept defined by data n (q (n)).

Based on the flow error CmQa obtained as described above, the flow QaTbl before correction is changed to the flow QaRef after correction.
Equation (1) shows an arithmetic expression for correcting the above. QaRef
= QaTbl × (1−CmQa) (1) According to the above equation (1), it is possible to output as a flow signal whose individual variation has been adjusted in the same manner as the flow signal adjusted by resistance trimming.

Here, as an example, the error in the state where the correction is not performed (before the correction) is, as shown in FIG.
A description will be given of I-AFS in which about% occurs.

For example, in the case of the AFS having the characteristics shown in FIG. 3, the error is -9.8% at the flow rates of 38 Kg / h and 55 Kg / h, and -2% at the flow rate of 100 Kg / h. Error data to be set as a correction constant.

FIG. 4 shows the result of setting the correction data 1 as an example. Here, the result after correction is indicated by a solid line, error data before correction is indicated by a broken line, and data 1 for correction is indicated by a black circle and a broken line. From this result, the error has been reduced to a maximum of about 2.3%, but has not yet reached the target (in this example, the target is 2% or less, that is, ± 2% or less in the band).

The reason why the error cannot be completely canceled may be that the measured error data deviates from the flow rate recognized inside the I-AFS.
That is, although the error data is -9.8% at the flow rate of 38 kg / h, the actual error differs from the error data, and the error cannot be completely eliminated from the measurement. There was sex.

Therefore, as one countermeasure, it is conceivable to set the flow point at the time of setting the correction data in consideration of an error from the actual value. However, in this method, the error is measured each time the correction data is set, and while the feedback is performed until the set value is optimized, the adjustment process is performed by setting the new correction data from the outside based on the result. However, there is a problem that complicated work is required and the number of man-hours is increased.

FIG. 5 shows the result of actually adjusting by cut-and-try and reducing the error of the corrected data.
Shown in As described above, if the adjustment data is matched while re-measuring several times, the error after correction can be reduced.

However, in this case, the number of adjustment steps is almost the same as that of the conventional resistance trimming method, and the effect of the digital trimming method which aims to reduce the number of adjustment steps cannot be obtained.

Therefore, in the present invention, the flow point at the time of correction and the correction data are set externally, but the calculating means itself corrects the error of the flow rate based on the input data, and the optimum value is obtained. A means for re-adjusting by internal calculation so as to obtain a proper correction value is newly provided.

This will be described with reference to FIG. The example of FIG. 1 is characterized in that an adjustment data correction unit 350 is added to the I-AFS which is the comparative example shown in FIG. Up to the point where the correction data is set in the adjustment step, the operation is performed in the same manner as in the example shown in FIG.

Here, the I-AFS maps the relationship between the flow rate and the error from the set adjustment data (the correction data in FIG. 4 is linearized internally). At this time, the flow rate data is adjusted by an error so as to approach an actual error, and the flow point of the setting data is changed and stored. The algorithm is shown in FIG.
Shown in The algorithm shown here is performed by the adjustment data correction unit 350.

In FIG. 10, in step 91, correction data is set in the data storage means 400 from outside the PC or the like. Next, in step 92, the correction data set in the data storage means is adjusted by the adjustment data correction means 350.
The flow point is adjusted by an error only once by feedback or the like so that the set correction data approaches an actual error.

Then, the flow point adjusted by the error is set as a new flow point in the data storage means 400 in step 93. As described above, by adding adjustment of the set correction data by an error by the adjustment data correction unit 350, the adjustment error of the I-AFS can be reduced.

On the other hand, the above-described method is an open control in which adjustment is performed only once based on error data set from the outside, so that errors may still remain.

Therefore, the flow rate actually calculated by the correction means 310 is fed back to the adjustment data correction means 350 in the adjustment process at the time of setting the adjustment data, thereby correcting the error data between the actually calculated flow rate and the true flow rate. Setting as a constant can further eliminate the adjustment error.

FIG. 2 shows the system configuration diagram, and FIG. 11 shows the algorithm. 2 and 11;
The difference from the examples shown in FIGS. 1 and 10 is that, after adjusting the correction data, a configuration for checking an error with a signal from the correction unit 310 is added. Steps 101 to 103 shown in FIG. 11 are the same as steps 91 to 93 shown in FIG.

In this state, the adjustment step (such as flowing air,
Under the condition that an I-AFS can be output such as application of a pseudo current), the numerical value calculation means 300 itself calculates (step 104) the flow rate from the relationship between the flow point set in the data storage means 400 and the error. Estimate your own error.

Then, it is determined in step 105 whether the error is within the allowable range (in this example, within ± 2% for the band), and if it is determined that the error is within the allowable range, step 10 is performed.
7, the adjustment data is stored in the data storage means 40 again.
The value is set to 0 and the adjustment process ends.

If it is determined in step 105 that the error is out of the allowable range, the process proceeds to step 106, in which the set flow rate data is corrected based on the error at that time and set as new adjustment data and set in the data storage means 400. The process returns to step 103.

Thereafter, the processing of steps 103 to 105 is repeated until the error falls within the allowable range, whereby the adjustment data itself can be optimized.

As described above, when the error is large, the correction data is adjusted again.
Can be set again. Also, since this algorithm adjusts the correction data inside the numerical calculation means 300, only the initial data setting is performed from the outside, and the subsequent work such as data setting from the outside is not performed. Therefore, it is possible to set correction data that can minimize the error.

As described above, even if the correction constant is initially set, the correction constant itself is self-adjusted by the numerical operation means of the I-AFS. Therefore, the accuracy can be improved even by setting the constant once, and the man-hour of the adjustment process is reduced. Also became possible to achieve.

That is, according to one embodiment of the present invention,
An air flow sensor having a numerical operation means and performing multi-point correction of two or more points by digital data for adjustment, wherein when setting a correction constant at the time of adjustment, the adjustment data taking into account an error appearing in an adjustment step is taken. It is possible to realize an air flow measurement sensor which is a sensor with a built-in arithmetic device, which can be set, and which can optimize the set correction constant by means of numerical calculation means of the sensor itself.

Although the above-described example has been described with reference to a heating resistor type air flow measuring sensor (device) as an example, the present invention can be applied to a sensor for detecting an analog signal other than the heating resistor type air flow measuring device. It is.

As a sensor for detecting an analog signal other than the heating resistor type air flow measuring device, there is a pressure sensor. This pressure sensor detects the pressure in the intake manifold, the discharge pressure of engine oil, and the like, instead of the air flow rate. This pressure sensor also has numerical calculation means similar to the above-described heating resistor type air flow measurement device, so that digital multipoint correction can be performed, and the adjustment process can be simplified and accuracy can be improved.

In the case of a pressure sensor, the air flow sensor circuit 100 in FIGS. 1 and 2 may be a pressure sensor circuit, and the flow rate converter 320 may be a pressure converter.

In the above-described example, the arithmetic processing of the numerical operation means 300 can be configured so that a processor or the like performs processing based on a processing program. In this case, the processing program can be externally stored in the means for storing the processing program.

A recording medium for storing the processing program can be realized as another embodiment of the present invention.

That is, it is a processing program recording medium for storing a processing program for correcting a measurement error correction constant of a sensor with a built-in arithmetic device having a numerical calculation means for correcting a measurement error.

In this processing program recording medium, a correction constant for correcting a measurement error of the sensor was internally adjusted based on an external signal and stored in the storage means, and the measurement was performed using the stored correction constant. Correct the value, compare the corrected value with the true value, adjust the correction constant until the difference between the corrected value and the true value is within a predetermined range,
A processing program for storing the obtained correction constant as a new correction constant in the storage unit is stored.

As another example of the processing program recording medium, there is provided an air flow sensor for detecting an intake air flow rate using a heating resistor, and means for converting an output signal of the air flow sensor into a digital signal. There is a processing program recording medium for storing a processing program for correcting a measurement error correction constant of a heating resistor type air flow measuring device having a numerical calculation means for correcting a flow rate error.

In this processing program recording medium, a correction constant for correcting the measurement error of the air flow sensor is internally adjusted based on an external signal and stored in the storage means. Correct the measured air flow value, compare the corrected air flow value with the true value,
A processing program for adjusting the correction constant until the difference between the corrected value and the true value falls within a predetermined range, and storing the obtained correction constant as a new correction constant in the storage means is stored. .

[0091]

According to the present invention, in a heating resistor type air flow rate measuring device for measuring the flow rate of intake air flowing into an internal combustion engine, only one adjustment step is required at the time of digital multi-point correction, and the number of steps in the adjustment step is reduced. Can be achieved, and the accuracy of the air flow measurement device can be improved.

Similarly, with a sensor for detecting an analog signal having a numerical operation means, the adjustment process can be simplified and the accuracy can be improved.

That is, a sensor having numerical calculation means for performing multipoint correction of two or more points using digital data for adjustment, and when setting a correction constant at the time of adjustment, an error appearing in the adjustment process is also taken into consideration. It is possible to realize a sensor with a built-in arithmetic device capable of setting the adjustment data and further optimizing the set correction constant by means of the numerical calculation means of the sensor itself.

Also, the present invention is a processing program recording medium for storing a processing program for correcting a measurement error correction constant of a sensor with a built-in arithmetic device having a numerical calculation means for correcting a measurement error. Only once, it is possible to realize a recording medium that records a processing program that can reduce the number of steps in the adjustment step and can improve the accuracy of the sensor with a built-in arithmetic device.

Further, there is provided an air flow rate sensor for detecting an intake air flow rate using a heating resistor, means for converting an output signal of the air flow rate sensor into a digital signal, and numerical value calculation means for correcting a flow rate error. A processing program recording medium for storing a processing program for correcting a measurement error correction constant of a heating resistor type air flow rate measuring device having a multi-point correction in a digital multi-point correction process, which reduces man-hours in the adjustment process. Can be achieved, and a recording medium recording a processing program capable of improving the accuracy of the air flow measuring device can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of a heating resistor type air flow measuring device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a system configuration of another example of the heating resistor type air flow measuring device according to one embodiment of the present invention.

FIG. 3 is a characteristic diagram showing output characteristics before correction of a heating resistor type air flow measuring device according to an embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a comparison between output characteristics before and after correction and a correction constant of the heating resistor type air flow measuring device according to one embodiment of the present invention.

FIG. 5 is a characteristic diagram of another example showing a comparison between output characteristics before and after correction and a correction constant of the heating resistor type air flow measuring device according to the embodiment of the present invention.

FIG. 6 is a partial cross-sectional view showing a state in which the heating resistor type air flow measuring device according to one embodiment of the present invention is attached to an intake pipe.

FIG. 7 is a circuit diagram illustrating a heating resistor type air flow measuring device according to an embodiment of the present invention.

FIG. 8 is a diagram for explaining a voltage-to-flow rate conversion map used in the heating resistor type air flow measuring device according to one embodiment of the present invention.

FIG. 9 is a diagram for explaining an error map as adjustment data for setting an error for each flow rate used in the heating resistor type air flow measuring device according to one embodiment of the present invention.

FIG. 10 is a flowchart illustrating an algorithm of a heating resistor type air flow measuring device according to an embodiment of the present invention.

FIG. 11 is a flowchart illustrating an algorithm of another example of a heating resistor type air flow measuring device according to an embodiment of the present invention.

FIG. 12 is an example of a system of a heating resistor type air flow measuring device having no function of the present invention, and is a block diagram for comparison with the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 air flow sensor 110 drive circuit 200 A / D conversion means 300 numerical calculation means 310 flow correction means 320 flow conversion means 330 communication means 350 adjustment data correction means 400 data storage means 500 D / A conversion means RH heating resistor RC temperature sensing Resistor

Claims (13)

[Claims] 1. A sensor for measuring an object to be measured, said sensor having a built-in arithmetic device having a numerical operation means for correcting a measurement error, wherein adjustment data for correcting a correction constant for correcting the measurement error of said sensor. A sensor with a built-in arithmetic device, comprising a correction unit. 2. A sensor for measuring an object to be measured, the sensor having a built-in arithmetic device having a numerical operation means for correcting a measurement error, wherein a correction constant for correcting the measurement error of the sensor is converted into an external signal. A sensor with a built-in arithmetic device, comprising an adjustment data correction unit for performing internal adjustment based on the data. 3. A sensor for measuring an object to be measured, the sensor having a built-in arithmetic device having a numerical calculation means for correcting a measurement error, wherein a correction constant for correcting a measurement error of the sensor is set by the numerical calculation means itself. A built-in arithmetic device sensor comprising an adjustment data correction unit for resetting the correction value to an optimum value based on the calculated error amount. 4. An air flow sensor for detecting an intake air flow rate by using a heating resistor, means for converting an output signal of the air flow sensor into a digital signal, and numerical value calculation means for correcting a flow error. A heating resistor type air flow measurement device comprising: a heating resistor type air flow measurement device comprising: an adjustment data correction unit for correcting a correction constant for correcting the flow rate error. 5. An air flow sensor for detecting an intake air flow rate using a heating resistor, means for converting an output signal of the air flow sensor into a digital signal, and numerical value calculation means for correcting a flow rate error. A heating resistor type air flow measurement device comprising: a heating resistor type air flow measurement device comprising: an adjustment data correction unit for performing an internal adjustment of a correction constant for correcting the flow rate error based on an external signal. . 6. An air flow rate sensor for detecting an intake air flow rate using a heating resistor, means for converting an output signal of the air flow rate sensor into a digital signal, and numerical value calculation means for correcting a flow rate error. The heating resistor type air flow rate measuring device having an adjustment data correcting means for resetting a correction constant for correcting the flow rate error to an optimum value based on the error amount calculated by the numerical value calculating means itself. Heating resistor type air flow measurement device. 7. An air flow sensor for detecting an intake air flow rate using a heating resistor, a means for converting an output signal of the air flow sensor into a digital signal, and a numerical operation means for correcting a flow error. In the heating resistor type air flow measuring device, the correction constant for correcting the flow rate error is an error map including a flow rate signal and error data. 8. An air flow sensor for detecting an intake air flow rate using a heating resistor, means for converting an output signal of the air flow sensor into a digital signal, and numerical value calculation means for correcting a flow error. In the heating resistor type air flow measuring device, an error is calculated from the flow signal input from outside and the flow converted from the output of the air flow sensor by the numerical calculation means, and the flow is converted from the output of the air flow sensor. And an error map for setting a correction constant for correcting the flow rate error according to the obtained error. 9. An air flow sensor for detecting an intake air flow rate using a heating resistor, and means for converting an output signal of the air flow sensor into a digital signal, and numerical value calculation means for correcting a flow rate error. In the heating resistor type air flow rate measuring device having the above, the error is calculated from the flow rate signal input from the outside and the flow rate converted from the output of the air flow rate sensor by the numerical calculation means, and is converted from the output of the air flow rate sensor. An error map for setting a correction constant for correcting the flow rate error by the flow rate and the obtained error is provided, and the numerical calculation means includes:
A heating resistor type air flow measurement device, wherein the error map is reset from the flow rate converted using the error map and the input flow signal again. 10. An air flow measuring apparatus according to claim 7, wherein said error map is stored in a data storage means. measuring device. 11. A sensor for measuring an object to be measured, which is a sensor with a built-in arithmetic device having numerical calculation means for correcting a measurement error, wherein data set as a correction constant for correcting the error is corrected by linear interpolation. A sensor with a built-in arithmetic device, wherein items used as a denominator are set at equal intervals when performing a map search, thereby simplifying linear interpolation calculation at the time of data search. 12. A processing program recording medium for storing a processing program for correcting a measurement error correction constant of a sensor with a built-in arithmetic device having a numerical calculation means for correcting a measurement error, wherein a correction constant for correcting the measurement error of the sensor is: Internally adjusted based on a signal from the outside and stored in the storage means, the measured value is corrected using the stored correction constant, the corrected value is compared with the true value, and the correction is performed. And adjusting a correction constant until the difference between the obtained value and the true value falls within a predetermined range, and storing a processing program for storing the obtained correction constant as a new correction constant in storage means. Characteristic processing program recording medium. 13. An air flow sensor for detecting an intake air flow rate by using a heating resistor, means for converting an output signal of the air flow sensor into a digital signal, and numerical operation means for correcting a flow rate error. In a processing program recording medium storing a processing program for correcting a measurement error correction constant of the heating resistor type air flow measuring device having a correction constant for correcting a measurement error of the air flow sensor,
Internally adjusted based on a signal from the outside and stored in the storage means, using the stored correction constant, correct the measured air flow value, and correct the corrected air flow value and the true value. A processing program for adjusting the correction constant until the difference between the value obtained by comparison and correction and the true value is within a predetermined range, and storing the obtained correction constant as a new correction constant in the storage means. A processing program recording medium characterized by storing.