KR930008681Y1 - Speed control apparatus for diesel engine - Google Patents

Abstract

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Description

Governor of diesel engine

1 is a block diagram of an embodiment of the present invention.

2 is a block diagram of a conventional example.

3 and 4 are explanatory diagrams comparing the operating characteristics of the embodiment of FIG. 1 with the conventional example of FIG.

* Explanation of symbols for main parts of the drawings

1: handle 2: commander

3: first comparator 4, 4a, 4b, 4c: PID controller

6: first switch 7: 2nd comparator

8, 8a, 8b, 8c: amplifier 10: second switch

11: driver 12: actuator

13: second detector 14: first detector

15: diesel engine 16: fuel rack

The present invention relates to a governing device of a diesel engine, such as a marine engine.

As a conventional example of this kind, there is one disclosed in Japanese Patent Laid-Open No. 60-32,959, which will be described below with reference to FIG.

In FIG. 2, (1) is a handle, (2) is a commander, and the command rotation speed signal is output from the commander 2 by operating the handle 1.

The first comparator 3 compares the command rotation speed signal with the actual rotation speed signal output from the first detector 14 that detects the actual rotation speed of the diesel engine 15, and compares the deviation with the first deviation. Output as a signal. The PID controllers 4a, 4b, and 4c have different PID constants a, b, and c, respectively, and input the first deviation signal, and proportional (P), integral (I), and derivative ( D) Perform the operation.

The 1st switch 5 selects any one of the position 5a, 5b, and 5c, and switches PID controller 4a, 4b, and 4c.

The first switch 6 inputs an actuator position signal or a fuel rack position signal from the second detector 13, which will be described later, and an actual rotational speed signal from the first detector 14, The first switch 5 is switched by the size thereof.

The second comparator 7 compares the output signals of the PID controllers 4a, 4b, and 4c input through the first switch 5 with the actuator position signal or the fuel rack position signal, and The deviation is output as the second deviation signal.

The amplifiers 8a, 8b, and 8c each have different amplification rates, and amplify the second deviation signal from the second comparator 7.

The second switch 9 selects any one of the positions 9a, 9b, and 9c to switch the amplifiers 8a, 8b, and 8c.

The second switch 10 inputs the second deviation signal and switches the second switch 9 according to its magnitude.

The driver 11 operates the actuator 12 due to the output signals of the amplifiers 8a, 8b, 8c input through the second switch 9.

The actuator 12 controls the position of the fuel rack 16 of the fuel pump (not shown). That is, the fuel supply amount to the diesel engine 15 is controlled.

In addition, the second detector 13 detects the position of the actuator 12 or the position of the fuel rack 16.

Now, in the drawing, the diesel engine 15 is operated at a constant speed at low load and low rotation, and the first switch 5 is cut into position (5a) and the second switch 9 is cut into position (9a). .

Next, when the handle 1 is operated to provide a higher command rotation speed signal, the first deviation signal from the first comparator 3 increases, so that the output signal of the PID controller 4a, The second deviation signal from the comparator 7 increases.

By the magnitude of the second deviation signal, the second switch 10 switches the second switch 9 to the position (9b) or (9c), inputs a larger deviation signal to the driver 11, Actuator 12 is operated at high speed.

As a result, when the signal from the second detector 13 increases and approaches the output signal of the PID controller 4a, the second deviation signal of the second comparator 7 decreases, and the second switch 10 The second switch 9 is switched to (9b) and (a) to finally select the amplifier 8a having the lowest amplification factor.

In addition, the first switch 6 switches the first switch 5 according to the magnitude of the signal from the first detector 14 and the second detector 13. The PID controllers 4a, 4b, and 4c are selected by changing the rotation speed and changing the position of the actuator 12 or the fuel rack 16. In other words, PID constants a, b, and c are selected according to the state of the engine 15 at that time.

Subsequently to the above-described conventional example, switching of the PID controllers 4a, 4b and 4c, that is, selection of the PID constants a, b and c is performed by the first switch 5, and the fuel rack position signal, If the actual rotational speed signal or the actuator position signal is used as an independent variable and the PID constants a, b, and c are dependent variables, the PID constant for the fuel rack position signal or the like is located near the switching point of the PID constants a, b, and c. Since a, b and c are discontinuous and the difference is also large, the hunting of the actual rotational speed to be controlled near this switching point continues long. This is illustrated by the dotted lines in FIGS. 3 and 4. These figures show the change of the actual rotation speed when the command rotation speed is increased to R2 at the time t1 when it is operating at a constant speed at rotation speed R1.

Accordingly, the technical means of the present invention, the commander for outputting the command speed signal by the steering wheel operation, the first detector for detecting the actual speed of the diesel engine and output the actual speed signal, these command speed signal and the actual A first comparator for comparing the rotational speed signals and outputting the deviation as a first deviation signal, a PID controller for PID operation of the first deviation signal, and an actuator for controlling the fuel rack position due to the output of the PID controller. In the governing of the diesel engine, the PID constant of the PID controller is continuously switched in accordance with at least one of a plurality of elements such as actual engine speed, horsepower, actuator position, fuel rack position, and the like.

According to the said means, when switching PID constants by element size, such as fuel rack position, actual rotation speed, actuator position, etc., since switching is performed continuously, there is no significant step up and down of PID constant at the time of switching. For this reason, the operation | movement of the whole control system becomes smooth compared with the conventional example, and rotation speed hunting at the time of switching is reduced.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1, 3, and 4. The same components as in the conventional example will be denoted by the same reference numerals as in the second drawing, and description thereof will be omitted.

In Fig. 1, the PID controller 4 continuously sets the PID constants in the form of a cut line close to a straight line with respect to the fuel rack position. It selects a number of representative values of the fuel rack positions to determine the optimal PID constants for these representative values, and the PID constants for the fuel rack positions that exist in this representative value are determined using the values of the PID constants already determined. The PID constants in the region above the minimum representative value and the region above the maximum representative value of the fuel rack position are used as the PID representative values for the minimum representative value and the latest representative value, respectively.

The PID constants are set in the form of cut lines, but they may be set in the form of curves.

In addition, although the fuel rack position signal of the second detector 13 is used as an element for switching the PID constant, the position of the actuator 12, the actual rotational signal from the first detector 14, the engine The horsepower of (15), the command rotation speed of the commander 2, etc. may be used, and one or a combination of these elements may be used.

Similarly to the PID controller 4, the amplifier 8 in the above embodiment also continuously switches the amplification factor, and the setting thereof is arbitrary.

FIG. 3 shows an example in which the PID constant is changed in accordance with the fuel rack position, and FIG. 4 shows an example in which the PID constant is changed in accordance with the integration between the actual rotation speed and the fuel rack position. These are examples in which the command rotation speed is increased to R2 at time t1 when the engine 15 is operating at a constant speed at the actual rotation speed R1. Hunting is greatly reduced as compared with the conventional example.

According to the present invention, since the PID constants are continuously switched by the fuel rack position, the actual rotation speed, the actuator position, and the like, the discontinuity point of the PID constants at the time of switching is eliminated, the operation is smooth, and the hunting of the rotation speed is reduced do.

Further, in the conventional example, a method of controlling the hunting of the rotational speed by setting a large number of switching points, that is, by setting a plurality of switching positions of the first switch 5 can be considered, but the discontinuous portion of the PID constant is It remains necessarily, and the number of PID controllers increases, which is undesirable. These problems are all solved by the present invention.

Claims (1)

The commander outputs the command speed signal by the steering wheel operation, the first detector which detects the actual speed of the diesel engine and outputs the actual speed signal, and compares the command speed signal with the actual speed signal to determine the deviation. A governor of a diesel engine having a first comparator for outputting as a first deviation signal, a PID controller for PID operation of the first deviation signal, and an actuator for controlling the position of the fuel rack due to the output of the PID controller. 12. A diesel engine governing device, configured to continuously switch PID constants of the PID controller according to at least one of a plurality of elements such as actual engine speed, horsepower, actuator position, fuel rack position, and the like.