JPH01285642A - Sensor with characteristic display and controller using same sensor - Google Patents

Abstract

PURPOSE:To prevent the deterioration of control accuracy caused by dispersion of a detected characteristic by installing a characteristic display means which outputs a converted characteristic value to outside in a sensor which detects the predetermined physical quantity and converts it to an electric signal having the predetermined functional relation so as to output it to outside. CONSTITUTION:A sensor 1 detects, for example, the predetermined physical quantity relating to the operating condition of an engine. In this case, the sensor 1 is formed with a detecting unit 11 which converts a detected physical quantity to an electric signal so as to output it to outside and a characteristic display unit 12 which outputs a converted characteristic value to outside. On the other hand, a controller 2 is formed with a converter 21 which converts the electric signal out of the detecting unit 11 to a digital signal and a storing means 23 which stores a converted functional relation value of multiple physical quantities with multiple electric signals. The controller 2 is further formed with a computing means 22 which selects the predetermined functional value from the storing means 23 corresponding to the characteristic value out of the characteristic display unit 12 and outputs a control signal on the basis of the physical quantity obtained from the predetermined functional value and the output out of the converter 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine control device, and particularly to an automobile engine control device using a microcomputer.

[Conventional technology]

Despite the complex operating conditions of automobile engines.

Demand for improved fuel efficiency and purification of exhaust gas continues to increase. In response to this, the use of microcomputers that facilitate complex control is increasing.

This type of engine control device includes one example, JP-A-62
No. 98219, which is comprised of a detection device (sensor) that detects the operating state of the engine, and a control device that operates based on the output from the detection device.

[Problem to be solved by the invention]

In the above-mentioned prior art, the physical quantity within the control device is determined based on the output of the detection device and unique storage characteristics provided in advance within the control device. Therefore, there is a problem in that the control accuracy of the entire engine control device decreases due to variations in the output characteristics of the detection device.

An object of the present invention is to provide a detection device and a control device that prevent a decrease in control accuracy due to variations in output characteristics of the detection device.

[Means to solve the problem]

In order to achieve the above object, in a sensor that detects a physical quantity, converts it into an electrical signal having a predetermined functional relationship with the physical quantity, and outputs it to the outside, a characteristic display means that outputs a characteristic value indicating the conversion characteristic to the outside is provided. establish.

and a storage means for storing each function value indicating a functional relationship corresponding to each conversion characteristic of the sensor with characteristic display having a plurality of characteristic display means, and the characteristic value and the electric signal from the sensor with characteristic display. a calculation means for inputting a function value, selecting a predetermined function value corresponding to the characteristic value from the respective function values, and outputting a control signal calculated based on a physical quantity obtained from the predetermined function value and the electric signal; It is recommended to combine it with a control device equipped with

[Effect]

The characteristic display means of the sensor with characteristic display externally outputs characteristic values indicating variations in conversion characteristics unique to the sensor. and a control device that inputs an electric signal and a characteristic value having a predetermined functional relationship with the physical quantity from the sensor,
The storage means stores each function value indicating the functional relationship of a plurality of sensors, and the calculation means selects a predetermined function value corresponding to the characteristic value from the stored function values, and calculates the predetermined function value and the above-mentioned function value. It outputs a control signal calculated based on the physical quantity obtained from the electrical signal.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

FIG. 1 is a diagram showing the overall configuration of a sensor with characteristic display and a control device using the sensor according to the present invention.

In FIG. 1, a sensor with characteristic display 1 includes a detection section 11 that converts and outputs a physical quantity into an electrical signal, and a characteristic display means 12 that outputs a characteristic value indicating the conversion characteristic of converting the physical quantity into an electrical signal. The control device 2 includes an analog-to-digital converter 21 that converts the electrical signal from the detection unit 11 into a digital signal, a storage device 23 that stores a function value indicating a conversion function relationship between a plurality of physical quantities and the electrical signal, and a characteristic A characteristic value of the sensor with display 1 is inputted, a predetermined function value corresponding to the characteristic value is selected from the storage means 23, and based on the physical quantity obtained from the predetermined function value and the output from the analog-to-digital converter 21. and a calculation means 22 for outputting a control signal.

FIG. 2 is a diagram showing an embodiment of the sensor 1 with characteristic display according to the present invention, and is an example of application to a hot wire type sensor.

In FIG. 2, a hot wire 102 is used to detect the air flow rate F and is placed in the air flow path 101. Compensation line 1
03 compensates for the temperature change of the air flow rate F, and the hot wire 1
Similar to 02, it is arranged in the air flow path 101.

A bridge circuit consisting of a hot wire 102, a compensation wire 103, and resistors 106 and 107, a differential amplifier 105 that detects the balanced state of the bridge, and a transistor 104 that controls the current supplied to the bridge circuit based on the output from the bridge circuit. The circuit consisting of the differential amplifier 105 operates according to the relationship shown in equation (1) below.

However, RH: Resistance value of hot wire 102 RC: Resistance value of compensation 1103 R106: Resistance value of resistor 106 R107: Resistance value of resistor 107 Here, RH is the resistance value of ceramic bobbin 401 as shown in FIG.
There is a structure in which a platinum wire 403 is wrapped around a lead wire 402, or a structure in which a platinum wire 403 is stretched around an insulating ring 404 as shown in FIG. 4, but both resistors have a large temperature coefficient. It is.

Jutte, R106 and R107 (7) ratio 't41102R
H can be heated to a constant temperature. That is, the hot wire 102
The electric power for heating the air becomes a function of the air flow rate F, and a voltage signal V can be obtained.

The relationship between the air flow rate F and the voltage signal V has large variations. For example, in the structure shown in Figure 3, this is the bobbin 40.
1, the winding method of the platinum wire 403, etc. In FIG. 4, there is a gap between the insulating ring 404 and the platinum 8403 due to the isothermal wire 102, and in FIG. This is due to

When this sensor is used, for example, as an air flow rate detector for engine control, the above error is much larger than the accuracy required for engine control. Therefore, this variation range is divided into, for example, eight ranks, B1 to B8, into widths that have sufficient accuracy for engine control, as shown in the output characteristic diagram shown in FIG. When manufacturing the air flow rate detector, determine which of the characteristics B1 to B8 it belongs to, cut the wire between the resistor R and the power supply 0 shown in Figure 2 (LO in Figure 2) L, and connect the characteristic signal. configure the

By doing so, it becomes possible to determine variations in the unique characteristics of each sensor 1 from the outside.

FIG. 6 is a diagram showing the configuration of the control device 2 combined with the sensor with characteristic display 1 of the above embodiment.

In FIG. 6, the arithmetic means 22 calculates, based on the characteristic signal,
Function value (for example, 232) that is the memory content of the storage means 23
Select the memory contents and analog/digital converter 2
Calculate the air flow rate from the output value of 1. By doing so, it becomes possible to correct variations in the characteristics of the sensor with characteristic display 1 and calculate the air flow rate with high accuracy.

FIG. 7 is a diagram showing the overall configuration of an engine control device to which the sensor with characteristic display 1 and the control device 2 combined therewith are applied.

In FIG. 7, based on the intake air flow rate Q of the engine detected by the air flow rate detector 1 and the engine rotation speed N detected by the rotation detector 3, the control device i! A microcomputer installed in the engine 2 determines the optimum ignition timing and optimum fuel injection amount, and drives the ignition device 4 and the fuel injection valve 5 to optimally control the engine operating state. By using the air flow rate detector 1 as the sensor 1 with a characteristic display, variations in characteristics can be corrected, which has the effect of enabling highly accurate control.

The above example uses an air flow rate detector, but
In an engine control device that determines the engine intake air flow rate from the intake pipe pressure, a similar effect can be obtained by providing a pressure detector with a characteristic display means for outputting a characteristic value for determining the pressure-output characteristic.

Furthermore, it is possible to apply the present invention to other control devices and various sensors regardless of engine control.

〔Effect of the invention〕

According to the present invention, the sensor that detects a physical quantity and converts it into an electrical signal having a predetermined functional relationship is provided with a characteristic display means that outputs a characteristic value indicating variation in the conversion characteristic to the outside,
By combining with a control device that selects a function value corresponding to the characteristic value from the storage means and corrects the conversion characteristic based on the function value, there is an excellent effect that highly accurate measurement and control can be performed.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a sensor with characteristic display according to the present invention and a control device using the same, Fig. 2 is a circuit diagram of a hot wire type sensor with characteristic display, and Figs. 3 and 4 are a diagram of the hot wire type sensor with characteristic display. FIG. 5 is a diagram showing the detailed structure, FIG. 5 is an output characteristic diagram, FIG. 6 is a diagram showing the configuration of the control device, and FIG. 7 is a diagram showing the overall configuration of the engine control device. DESCRIPTION OF SYMBOLS 1...Sensor with characteristic display, 2...Control device, 11.
...detection section, 12...characteristic display means, 22...calculation means, 23...storage means. Figure 1 2 z
12 ・Boss table with 1 it 5 1 (2 ・ system '4!FJ3
711 z2;ijI9MitKaidobe 2j
・Memorial smell 3 Kaede Fig. 2 [----1 Fig. 3 340 Fig. 5 Fig. 6 Fig. 7

Claims (3)

[Claims] 1. A sensor that detects a physical quantity, converts it into an electrical signal having a predetermined functional relationship with the physical quantity, and outputs it to the outside, characterized in that it is provided with a characteristic display means that outputs a characteristic value indicating the conversion characteristic to the outside. Sensor with display. 2. 2. The sensor with characteristic display according to claim 1, wherein the signal indicating the characteristic value is a digital signal consisting of a plurality of bits. 3. a storage means for storing each function value indicating a functional relationship corresponding to the conversion characteristic of each of the plurality of sensors with characteristic display; It is characterized by comprising a calculation means for selecting a predetermined function value corresponding to the characteristic value from the function values and outputting a control signal calculated based on the physical quantity obtained from the predetermined function value and the electric signal. A control device using the sensor with characteristic display according to claim 1 or 2.