JPS58214644A - Control system of engine-driven compressor - Google Patents

Abstract

PURPOSE:To control the tank pressure stably and rapidly in a control system for engine revolution number and suction air amount by operating a governor lever and a suction air amount control valve on the basis of a specific condition of a measured value of the tank pressure. CONSTITUTION:A stepping motor is operated by the output pulse from a microcomputer for operating a governor lever and a suction air amount control valve of a compressor. The number of pulses are commanded by the sum of the information proportional to the difference between the measured value and the set value of the tank pressure and that proportional to the difference between measured values of the tank pressure of the last time and this time. This system is a system of proportion + integration + differentiation, and permits to control the tank pressure rapidly and stably and also prevent the hunting phenomenon.

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the engine's governor lever and the operating lever of the compressor's intake air amount limiting valve are linked via a stepping motor driven by output pulses from a microcomputer to control engine speed and intake air loss. This control method uses a computer to detect the tank pressure at regular intervals, for example, every 10 milliseconds, and transmit pulses based on the information.

The first invention is an integral control method.

This method (A,) is a method as shown in (a) of Figure 1 and (a) of Figure 2, and is performed only by comparing the magnitude of the tank set pressure and the measured pressure of the tank. This is a control method in which a certain number of Nockles is output in the DOWn direction if the value is large, and in the opposite case, it is output in the UP direction.

〃<〃 When the reverse tank pressure is as shown in Fig. 2, the Cockles number outputs a foot number 7 as shown in (a). This method is characterized by good response.

The second invention is a proportional ten integral method.

Bokuto gB) is a method as shown in Fig. 1 (b) and Fig. 2 (b), in which the number of pulses is proportional to the difference between the set pressure and the measured pressure of the tank. direction,
In the case of a negative value, this is a control method that outputs in the direction of DOWn, and this method is also characterized by a good response like the previous method.

In other words, proportional integral method...Pulse number - α (set pressure Kerr measurement pressure) For example, when the tank pressure is α = 10 in Figure 2, the output pulse number in Figure 2 (b) is output. A control curve as shown in FIG. 1(b) is obtained. This method also has the characteristic of good response.

The third invention uses a combination of a proportional-integral method and a differential method.

As shown in (0) in Figure 1 and (0) in Figure 2, this method (0) uses information proportional to the difference between the set value and the measured tank pressure value, the previous tank pressure measurement pupil, and the current tank pressure measurement value. In this method, the number of pulses is commanded by the sum of information proportional to the difference from the pressure measurement value.

Since this method (0) uses a microcomputer, it utilizes its storage device and also uses the previous tank pressure information to perform smoother control, and it uses the proportional ten integral function of the second invention. This is a method with the addition of a differential method.

That is, the number of pulses - α (set pressure vs. current measured pressure) + β (previously measured pressure vs. current measured pressure) For example, if the tank pressure is α = 10 in Figure 2. When β=20, the number of pulses is as shown in FIG. 2 (0), and the control curve is a solid curve that is the sum of the first term curve (dashed line) and the second term curve (dotted line).

As explained above, by using any of the methods (A), (B), and (0), the method (0) has the common effect of being able to perform extremely accurate control because it is pulse controlled by a computer. Second, the second term acts as a damper against sudden changes in pressure, and as shown in Figure 1 (0), the tank pressure can be stabilized more quickly than in the methods (A) and (13) above, thereby preventing hunting. This phenomenon can also be prevented.

Furthermore, by adjusting the constants α and β, the damping effect can be easily changed.

[Brief explanation of the drawing]

FIG. 1(a) is a diagram showing the integral control method of the first invention, FIG. 1(a) is a diagram showing the proportional ten-integral method of the second invention, and FIG. FIG. 2 is an explanatory diagram of the relationship between the measured value of tank pressure and the number of output pulses of each method (A, ), (B), (0). (Mi(↓KC coloring((

Claims (1)

[Claims] A system in which the engine's governor lever and the operating lever of the compressor's intake air amount limiting valve are linked via a stepping motor driven by output pulses from a microcomputer to control the engine speed and intake air amount. A control method for an engine-driven compressor, characterized in that, in order to maintain the set pressure of the tank pressure at a constant value, the output pulses are set as a command of a constant number of pulses based on information comparing the magnitude of the set value and the measured value of the tank. λ This method controls the engine speed and intake air amount by linking the engine governor lever and the compressor's intake air amount limiting valve operating lever via a stepping motor driven by output pulses from a microcomputer. A control method for an engine-driven compressor, characterized in that, in order to maintain a set pressure at a constant value, the number of pulses is commanded based on information proportional to a difference between a set value and a measured value in a tank. 3. This method controls the engine speed and intake air amount by linking the engine governor lever and the operating lever of the compressor's intake air amount limiting valve via a stepping motor driven by output pulses from a microcomputer. In order to maintain the set pressure at a constant value, the previous tank pressure is A control method for an engine-driven compressor, characterized in that the number of pulses is commanded.