JPS5940732Y2 - Proportional control device for electromagnetic actuators - Google Patents

Description

[Detailed description of the invention] This invention is an electromagnetic actuator that generates continuous mechanical displacement, such as by linearly controlling the flow rate, opening degree, or position, to correct the amount of air in an automobile carburetor or to adjust the amount of air in an exhaust system. This invention relates to a proportional control solenoid valve that controls the amount of secondary air flowing into the air.

Conventionally, in order to linearly control this type of electromagnetic actuator, it is well known to linearly change the current supplied to the solenoid.

In this conventionally well-known configuration, the current is simply changed linearly, so when the direction of increase/decrease in the solenoid supply current is reversed to reverse the direction of displacement, the amount of displacement of the electromagnetic actuator will change due to the hysteresis characteristic. Since the opening/closing direction is reversed after a delay of 1 minute, a major drawback is poor responsiveness.

Therefore, the present invention changes the supply current of the electromagnetic actuator linearly and changes it stepwise when the direction of change changes, thereby correcting the hysteresis characteristic of the displacement amount with respect to the current of the electromagnetic actuator. The main purpose of this invention is to provide a proportional control device with excellent displacement responsiveness.

Furthermore, the present invention is suitable for systems that feedback control the air-fuel ratio by adjusting the displacement amount, or opening degree, of a proportional control solenoid valve according to the exhaust gas components of the engine. A control signal generating circuit such as an integrator circuit that generates an electrical control signal that is switched between increasing and decreasing linearly is provided, and the control signal generating circuit causes the electrical control signal to be changed in steps at the time of switching. Another object of the present invention is to provide a proportional control device for an electromagnetic actuator, which is provided with electrical control means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An explanation will be given below based on an embodiment of the present invention shown in the figures.

Figure 1 is a schematic diagram of a solenoid valve, where 1 is a solenoid coil,
2 is a moving core, 3 is a pulp connected to the moving core, 4 is a spring, and 5 and 6 are air passages, for example, where the amount of air flowing in the direction shown by the white arrow is controlled, and the known air-fuel ratio feedback control is performed. shall be taken as a thing.

FIG. 2 shows a first embodiment of the electric circuit section for controlling the solenoid, which is composed of an integrating circuit 11, a step signal generating circuit 10, and an amplifier circuit 12. It consists of an integrator and resistors 114 and 115.

Further, the step generation circuit 10 includes resistors 101, 102,
The amplifier circuit 1 is composed of a 103° transistor 104.
2 is an operational amplifier 121.2 serving as a buffer. resistance 122
゜123, 124, Darlington connection transistor 12
5 is configured as a known constant current control circuit.

13 is a command signal input terminal indicating an increase/decrease in the valve opening;
A binary signal indicating a decrease at the "IGH" level and an increase at the "LOW" level is input from a known air-fuel ratio detection device.

Further, the voltage of the battery mounted on the vehicle is applied to the 10B terminal, and a constant voltage obtained by stabilizing the battery voltage is applied to the Vcc terminal.

In the above configuration, when the valve opening degree is decreased, the signal input terminal 13 is at the "High" level, and the output (1) of the integrating circuit 11 falls linearly in accordance with the integral constant.

On the other hand, since the transistor 104 is conductive, the non-inverting input terminal potential V2 of the operational amplifier 111 forming the integrator is
It is given by the following formula.

However, Rn indicates the resistance value of resistance number n in FIG. 2, and the equivalent internal resistance of the transistor 104 itself is ignored.

Next, when the command signal for increasing the valve opening, that is, the signal input terminal 13 changes to the "LOW" level, the transistor 104 is cut off, so that V2 is given by the following equation.

That is, the difference Δv2 between equations (2) and (1) increases in a stepwise manner.

This step change causes the operational amplifier 1 to act as an integrator operation.
11 inverting input terminal, output via capacitor 112■
1.

Therefore, the output voltage v1 increases stepwise by Δv2, and then increases linearly according to the integral constant.

When the command signal to decrease the valve opening degree, that is, the signal input terminal 13 changes to the "HIGH" level again, the output voltage 1 of the integrating circuit 11 decreases by ΔV2 in a stepwise manner.
After that, it falls linearly according to the integral constant.

The above operation will be explained with reference to FIG. 3. In order to increase the valve opening degree, the current ■ is increasing, and when a signal to decrease the opening degree is inputted when reaching point A, the step change △■ 2 corresponds to ΔI in FIG. 3, the operating point +7A instantaneously shifts to point B, and the valve opening, that is, the stroke S of the moving core, decreases along the characteristic curve.

That is, since the current is changed stepwise when switching between increasing and decreasing the valve opening, the change characteristics of this current (2) match the hysteresis characteristics of the solenoid valve.

FIG. 4 shows a second embodiment of the electric circuit section, which includes an integral constant increasing circuit 20 in place of the step signal generating circuit 10 of the first embodiment, and its operation will be explained below.

When the signal input terminal 13 is in a steady state, the potential at the connection point between the resistors 204 and 205 (assumed to be V3) is given by the following equation.

Further, the non-inverting input terminal potential of each of the comparators 210 and 211 is set to V4tV5, and V3. ■4. The v50 size relationship is set as follows.

0 <V5 <V3 <V4 <Vce In other words, the output of the comparator 210 is at a "High" level, and the output of the comparator 211 is at a "Low" level, and both transistors 214 and 217 are off.

Now, the signal input terminal 13 is higher than the "High" level.
w'' level, that is, when the request changes from decreasing to increasing the valve opening, the capacitor 201 differentiates the potential change at the signal input terminal 13, and V3 is maintained over a certain period of time (TI). The output becomes V3 or less, and the comparator 21
The output of 1 becomes "High" level.

Therefore, the transistor 217 is turned on, and the charging current of the capacitor 112 of the integrating circuit 11 flows through the resistor 216 as well as the resistor 113.

When the time T1 has elapsed, the transistor 217 is turned off, and from then on, the charging current of the capacitor 112 flows only through the resistor 113.

That is, when the valve opening increase/decrease signal changes from decreasing to increasing, the solenoid current increases with a steep slope for a certain period of time T1,
Thereafter, it rises at a normal slope, and by shortening T1, the same operation as in the first embodiment can be obtained.

On the other hand, the signal input terminal 13 goes from the 'LOW' level to the 'HIGH' level.
h” level, for a certain period of time (T2)
The output of the comparator 210 becomes "Low" level, the transistor 214 is turned on, and the solenoid current falls at a steep slope.

Then, after a certain period of time T2 has elapsed, it descends at a normal slope.

In the first embodiment, the amount of current that is added or subtracted in steps to the solenoid current that changes linearly is constant regardless of the valve opening amount. However, for a solenoid valve whose hysteresis width changes depending on the valve opening amount In the second embodiment, a circuit that calculates and outputs an extra current to flow through the capacitor 112 during TI and T2 using the valve opening amount as input, detects the amount of movement of the moving core, and calculates and outputs the current that is passed through the capacitor 112 during the above-mentioned TI and T2. By providing a circuit that changes the value, it is possible to compensate for hysteresis in any valve opening position.

Next, in the configuration of FIG. 5 showing the third embodiment of the electric circuit section, a resistor 3 is connected in series to the integrator input side with respect to the integrator capacitor 112 of the integrating circuit 11 in the first embodiment.
In this fourth embodiment, each time the output of the signal input terminal 13 is inverted, the potential (constant) of the inverting input terminal of the operational amplifier 111 forming the integrator is used as a reference.
The potential at the connection point between the resistor 300 and the capacitors 11 and 2 changes stepwise in the positive and negative directions, and the integrator output v3 also changes stepwise by a certain amount and then rises or falls linearly, which causes hysteresis of the solenoid valve. is canceled out by this stepwise change in the integral output.

As described above, according to the present invention, an electrical control signal that linearly changes the displacement amount of an electromagnetic actuator is generated in accordance with a command signal, and when increasing or decreasing this control signal, the electric control signal is added or decreased in a stepwise manner. Since it is configured to subtract, when the direction of change of the electromagnetic actuator is reversed, the solenoid current changes in a stepwise manner, and the hysteresis width of the solenoid valve can be instantly compensated for, greatly improving responsiveness when reversing. .

According to the second embodiment shown in FIG. 4, the stepwise change amount when the valve opening amount "decrease" → "increase" and the stepwise change amount when "increase" → "decrease" are controlled by the resistor 215. Spring 4 can be set independently by 216.
electromagnetic actuator (
It is also possible to compensate for axial mechanical hysteresis of the solenoid valve.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a solenoid valve that is an example of an electromagnetic actuator for implementing the present invention, and FIG. 2 is an electrical wiring diagram showing a first example of an electric circuit section among the embodiments of the present invention. Figure 3 is the first
FIG. 4 is an electrical wiring diagram showing a second embodiment of the electric circuit section, and FIG. 5 is an electrical wiring diagram showing a third embodiment of the electric circuit section. 1... Solenoid coil of a solenoid valve forming an electromagnetic actuator 11... Integrating circuit forming a control signal generation circuit, 12... Amplifying circuit, 10, 20, 300.
In each embodiment, a step signal generation circuit, an integral constant increasing circuit, and a resistor serve as control means.

Claims (1)

[Scope of utility model registration request] A control signal generation circuit that generates an electrical control signal that is switched to gradually increase or decrease over time in response to an input command signal; an electromagnetic actuator having a hysteresis characteristic between an electrical control signal and mechanical displacement; and an electromagnetic actuator that controls the control signal generation circuit in response to switching of the command signal, and increases the electrical control signal in a stepwise manner when starting to gradually increase the electrical control signal. 1. A proportional control device for an electromagnetic actuator, characterized in that the proportional control device comprises a control means for decreasing the amount in steps when the gradual decrease starts.