JPH01227846A - Engine controller - Google Patents

Abstract

PURPOSE:To eliminate the need for complex adjustment for a sensor and solve the problem of variation in detecting characteristics by providing a memory in which the detecting characteristics of the relation between both the physical quantity and the detected signal concerning the operation condition of an engine detected by the sensor. CONSTITUTION:The major part of an engine controller consists of an air flow race detecting part 1 and a controlling part 2. The air flow rate detecting part 1 contains both an air flow rate detector 11 and ROM 12. The detecting characteristics of the relation between both the air flow rate, which is physical quantity detected by the air flow rate detector 11 and and the detected signal is read into ROM 12. On the other hand the controlling part 2 contains both an AD converter 21 and an arithmetic operation part 22. The output terminal of the air flow rate detector 11 is connected to the input terminal of the AD converter 21, and the output terminals of both the AD converter 21 and ROM 12 are connected to the input terminal of the arithmetic operation part 22. Thus the need for complex adjustment for the air flow rate detector 11 can be eliminated and the problem of variation in detecting characteristics be solved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an engine control device.

[Conventional technology]

A sensor that detects the physical quantities necessary for engine operation is built into the engine control device, and a microcomputer is used to optimize the operating conditions, such as the fuel injection amount and ignition timing of an automobile engine, based on the detection signal of this sensor. The state is being set. In particular, automobile engines are required to set various conditions such as improving fuel efficiency and purifying exhaust gas under complex driving conditions, so engine control devices such as those described above are required. .

In this type of engine control device, if a failure occurs in the intake air flow rate measuring sensor, for example, engine control data becomes abnormal, making stable engine control impossible. Therefore, Japanese Patent Application Laid-Open No. 62-55519 proposes a control device for an internal combustion engine that detects an abnormality in an intake air flow rate measuring sensor by monitoring the pulse width of the output signal of the intake air flow rate measuring sensor. In this proposal, when an abnormality occurs, a time width signal is created using abnormality data previously written in the ROM, and the injection amount is calculated based on this signal, thereby performing fail-safe control of the engine.

[Problem to be solved by the invention]

In the control device according to the above-mentioned proposal, when a failure occurring in a sensor is detected, it is possible to perform fail-safe control of the engine by performing calculations such as the injection amount using abnormality data written in advance in the ROM. . However, with the proposed control device, it is not possible to correct the difference in detection characteristics between the detection physical quantity and the detection signal of each sensor.

However, as this type of engine control device uses a large number of sensors to perform complex control with high precision, it is necessary to improve the accuracy of the detection characteristics between the physical quantity detected by the sensor and the detection signal. Moreover, it is necessary to eliminate this variation.

Therefore, it is necessary to measure the detection characteristics between the detected physical quantity and the detection signal for the sensor, and if the detection characteristics are not within a predetermined tolerance range, the detection characteristics must be adjusted. It is almost impossible to adjust the detection characteristics of the sensor itself, and in such cases, it is necessary to incorporate a detection characteristics correction circuit into the engine control device to adjust the detection characteristics. There is.

Adjusting the detection characteristics of this sensor is complicated and requires a large number of man-hours, and incorporating a separate correction circuit complicates the engine control device and increases manufacturing costs.

The present invention was made in order to solve the problem of such an engine control device, and its purpose is to eliminate the need for adjusting the complicated detection characteristics of sensors, and to eliminate variations in the detection characteristics of sensors with a simple structure. An object of the present invention is to provide an engine control device that does not cause a decrease in control accuracy.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention includes a detection device section equipped with a sensor that detects a physical quantity related to the operating conditions of an engine and outputs a detection signal, and an output signal of the detection device section is inputted, In the engine control device, the engine control device includes a control section that controls the engine under predetermined conditions with respect to the output signal, and a storage device in which a detection characteristic between the detection physical quantity of the sensor and the detection signal is written is stored in the detection device section. A calibration data signal corresponding to the detection characteristics written in the storage device is input from the detection device section to the control section.

[Effect]

In the present invention, when the sensor of the detection device section detects a physical quantity related to the operating conditions, for example, the intake air flow rate of the engine,
The detection characteristics between the detected physical quantity and the detection signal of the sensor are read from the storage device provided in the detection device section, and the calibration data signal of the read detection characteristics is output from the detection device section to the control section. be done.

This calibration data signal calibrates the output signal of the detection device section, and the control section controls the engine with calibrated variations in the detection characteristics of the sensor, achieving highly accurate engine control that is independent of the detection characteristics of the sensor. be done.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 5.

Here, FIGS. 1 to 3 are diagrams for explaining the present invention in detail, with FIG. 1 being a block diagram showing the configuration of the main parts, FIG. 2 being a block diagram showing the overall configuration, and FIG. A circuit diagram showing the configuration of an air flow rate detection section using a hot wire air flow meter, Figure 4 (
a) and (b) are plan views showing the structure of the hot wire of the hot wire air flow meter, and FIG. 5 is a characteristic diagram of the hot wire air flow meter.

In the embodiment, as shown in FIG. 1, the air flow rate detector 1 is provided with an air flow rate detector 11 and a ROM 12.
A detection characteristic between the air flow rate, which is a physical quantity detected by the air flow rate detector 11, and a detection signal is written in M12. Further, the control unit 2 is provided with an AD converter 21 and a calculation unit 22, and the output terminal of the air flow rate detector 11 described above is connected to the input terminal of the AD converter 21. and the output terminal of the aforementioned ROM 12 are connected to the input terminal of the arithmetic unit 22.

Although FIG. 1 shows the state of connection between the air flow rate detection section 1 and the control section 2, the overall configuration of the embodiment is as shown in FIG. Rotation speed detection section 3
is connected to the control section 2, and an ignition device 4 and a fuel injection valve 5 are connected to output terminals of the control section 2, respectively.

In addition, in the embodiment, a hot wire air flow meter as shown in FIG. 3 is used as the air flow rate detector 11, and the hot wire 1
02. Compensation line 103. A bridge circuit is formed by the resistor 106 and the resistor 107, the connecting point between the hot wire 102 and the resistor 16 is connected to the non-inverting input terminal of the differential amplifier 105, and the connecting point between the compensation line 103 and the resistor 107 is connected to the inverting input terminal of the differential amplifier 105. connected to the input terminal.

Further, the output terminal of the differential amplifier 105 is connected to the transistor 1
The emitter of this transistor 104 is connected to the connection point of the heating wire 102 and the compensation wire 103, and the power supply is connected between the collector of the transistor 104 and the connection point of the resistor 106 and the resistor 107 from the power supply terminals P and N. is supplied.

The aforementioned hot wire 102 is a hot wire for detecting air flow rate,
The compensation line 103 is for compensating for changes in the temperature of the air, and the hot wire 102 and the compensation line 103 are arranged within the intake air passage 101 of the engine, which is shown by dotted lines in FIG. Further, the hot wire 102 is formed in a structure in which a platinum wire 403 is wound around a ceramic bobbin 401 as shown in FIG. It is formed in a structure in which wires 403 are stretched, and has a large temperature coefficient.

In an embodiment of such a configuration, the air flow rate detector 11
and the rotation speed detector of the rotation speed detection section 3 constitute a sensor,
The air flow rate detection section 1 and the rotation speed detection section 3 constitute a detection device section, and the ROM 12 and the RO provided in the rotation speed detection section 3 constitute a detection device section.
M constitutes a storage device.

The operation of the embodiment having the above configuration will be described next.

In FIG. 3, the resistance value of the hot wire 102 is Rx, and the compensation wire 1
The resistance value of resistor 106 is Rc, the resistance value of resistor 106 is R3゜6,
When the resistance value of the resistor 107 is RIO'l, the resistance value R of the hot wire 102 at the time of equilibrium of the bridge circuit is given by the following equation.

R,=Rr company・R,-・-(1) R1@'1 In FIG. 3, the intake air flow rate F increases and the hot wire 102
When the temperature of the hot wire 102 decreases, the resistance value of the hot wire 102 becomes smaller, so heating power is supplied from the power supply terminal P according to the output signal of the differential amplifier 105, and the hot wire 102 is heated.

Therefore, the electric power for heating the hot wire 102 is a function of the intake air flow rate F, and the intake air flow 31F can be determined from the voltage signal (■) at the non-inverting input terminal of the differential amplifier 105.

As shown in FIG. 1, the aforementioned voltage signal ■, which is the detection signal of the air flow rate detector 11, is input to the AD converter 21 of the control unit 2, converted to a digital signal, and input to the calculation unit 22. Ru.

On the other hand, the detection characteristic between the intake air flow rate, which is the detected physical quantity of the air flow rate detector 11, and the detection signal is read out from the ROM 12 of the air flow rate detection section 1, and the calibration data signal of this detection characteristic is sent to the control section 2. It is input to the calculation unit 22.

In this calculation section 22, the air flow rate detector 11 inputted from the AD converter 21 is
The control section 2 outputs a control signal Q based on the calibrated detection signal.

Similarly, a detection signal and a calibration data signal are input from the rotation speed detection section 3 to the calculation section 22, and the calculation section 22 outputs a control signal N based on the calibrated detection signal.

In this way, the calculation unit 22 composed of a microcomputer provided in the control unit 2 calculates the intake air amount control signal Q and the engine rotational speed control signal N, and these control signals cause the ignition device 4 to be activated. Ignition at the optimum timing and setting of the optimum injection amount for the fuel injection valve 5 are performed.

Taking the air flow rate detector 11 as an example, there is a curve 50 between the detection signal output voltage ■ and the intake air flow rate F in FIG.
1,502.503, there are considerable differences in the detection characteristics of individual air flow rate detectors. This is due to the diameter of the bobbin 401 and the way the platinum wire 403 is wound when the hot wire 102 of the air flow rate detector 11 has the structure shown in FIG. 4(a). In the structure shown, the diameter of the insulating ring 404, the diameter of the insulating ring 404 and the platinum v
It is related to the interval of A403. Also, this is hot wire 102
It is also related to the difference in the arrangement position within the air passage 101.
The difference shown in FIG. 5 is considerably larger than the tolerance range required for highly accurate control of the engine.

However, in the embodiment, as described above, variations in the detection characteristics of the air flow rate detector 11, which is a sensor, are completely calibrated by the calibration data signal from the ROM 12, and highly accurate engine control that does not depend on the detection characteristics of the sensor is achieved. will be carried out.

In addition, the detection characteristics and calibration data of the sensors to be incorporated into the engine control device can be written in the ROM 12 when manufacturing the engine control device, and there is no need to make complicated adjustment of the detection characteristics, and the structure is simple, reducing manufacturing costs. You can also do it.

In addition, in the embodiment, a case where the intake air flow rate is measured by a hot wire air flow meter has been described, but the present invention is not limited to the embodiment, and the present invention is not limited to the embodiment, and can be applied to a structure in which the intake air flow rate of the engine is determined from the intake pipe pressure. It can also be taken as a thing.

〔Effect of the invention〕

As explained in detail above, the present invention can be easily manufactured without adjusting the detection characteristics of the sensor, reducing manufacturing costs, and is not affected by variations in the detection characteristics of the sensor. , it is possible to perform high-precision control of the engine.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the main parts of the embodiment of the present invention, FIG. 2 is a block diagram showing the overall configuration of the embodiment of the present invention, and FIG. 3 is the air flow rate detection section of the embodiment of the present invention. 4(a) and 4(b) are plan views showing the structure of the hot wire of the hot wire air flowmeter, and FIG. 5 is a characteristic diagram of the hot wire air flowmeter. 1-----air flow rate detection section, 2--control section, 3
.--Rotation speed detection unit, 11--Air flow rate detector, 12--ROM, 22--Arithmetic unit. Figure 1 Figure 2 Figure 3 Figure 4 (0) (b) Figure 5 Intake 9 Airflow 1F

Claims (4)

[Claims] 1. a detection device unit equipped with a sensor that detects a physical quantity related to the operating conditions of the engine and outputs a detection signal;
In an engine control device having an output signal of the detection device section and a control section that controls the engine under predetermined conditions in response to the output signal, a detection characteristic between the detection physical quantity of the sensor and the detection signal is written. a storage device provided in the detection device section, and configured such that a calibration data signal of the detection characteristics written in the storage device is input from the detection device section to the control section. Characteristic engine control device. 2. The engine control device according to claim 1, wherein the sensor is an air flow meter that detects the intake air flow rate of the engine. 3. 2. The engine control device according to claim 1, wherein the sensor is a pressure gauge that detects pressure within an intake pipe of the engine. 4. In claim 1 or claim 2, the storage device is RO
An engine control device characterized in that it is an M (read-only memory circuit).