JPS6133982B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adjusting device for adjusting the rotational speed of an engine to a set value.

A conventional device of this type is shown in FIG. In the figure, 1 is an engine, 2 is a signal generator such as a generator or rotation sensor that generates a waveform output with a frequency proportional to the engine rotation speed, and 3 is a signal generator f that generates a rotation speed voltage 100 that is proportional to the engine rotation speed. -v converter, 4 and 5 are resistors, 6 is an operational amplifier that forms a differential amplifier with the resistors 4 and 5 and outputs a comparison voltage 300, 7 adjusts a set voltage 200 proportional to the target rotation speed variable resistor; 8 is a periodic waveform generator that generates a sawtooth wave 400 at a constant period; 9 is a comparator that compares the comparison voltage 300 with the sawtooth wave 400 and generates a drive pulse 500; 10 is a resistor; 1
1 is a transistor, and 12 is an actuator for operating an accelerator of the engine 1 and the like.

Next, the operation will be explained. When the variable resistor 7 is adjusted to increase the set voltage 200, the comparison voltage 300 increases, the duty of the drive pulse 500 increases, and the actuator 12 operates to reduce the engine 1.
The rotation speed of increases. When the rotation speed increases, the output frequency of the signal generator 2 increases, and the rotation speed voltage 10
0 rises. When the rotational speed voltage 100 increases,
Due to the function of differential amplifiers 4, 5, and 6, comparison voltage 3
00 is lowered. When the comparison voltage 300 decreases, the duty of the drive pulse 500 decreases, the actuator 12 operates, and the rotational speed of the engine 1 decreases. Due to such an operation, the rotational speed of the engine 1 corresponds to the set voltage 200.

Since the conventional speed governor is configured as described above, the operating amount of the actuator, that is, the accelerator opening, etc., corresponds to the voltage difference between the rotational speed voltage 100 and the set voltage 200. Therefore, when the load of the engine is changed, the target rotational speed cannot be approached unless the voltage difference is generated corresponding to the amount of change in the load, resulting in a disadvantage that the rotational speed changes. FIG. 2 shows an example of the rotational speed vs. load characteristic of the conventional device, which uses the target rotational speed as a parameter, and it can be seen that the controlled rotational speed decreases as the load torque increases.

The f-V converter 3, which generates a voltage output proportional to the rotational speed, is composed of a fixed-time pulse generation circuit that generates a duty pulse corresponding to the rotational speed, and an integration circuit that integrates and smoothes this duty pulse. However, the output of the integrating circuit for smoothing has poor responsiveness to fluctuations in rotation speed.
Therefore, the responsiveness of rotation speed control was poor.

This invention was made to eliminate the drawbacks of the conventional ones as described above, and even if the engine load changes, the rotation speed will not deviate from the target rotation speed.
Moreover, it is an object of the present invention to provide a speed governor with good control responsiveness.

An embodiment of the present invention will be described below with reference to the drawings. In Fig. 3, F-V generates a voltage output corresponding to (inversely proportional to) the output frequency of signal generator 2.
The converter 3 is constructed as follows. That is, 31 is a waveform shaper that converts the output of the signal generator 2 into square wave pulses, 32 is a capacitor that differentiates the output of this waveform shaper, 33 is a resistor, and 34 is the differential output given through this resistor. 35 is a resistor, 36 is a capacitor that is repeatedly charged via the resistor 35 in synchronization with the operation of the transistor 34 to generate a sawtooth wave voltage 400, and 37 is a voltage constant with this sawtooth wave voltage. A comparator 38 generates an L level constant time pulse by comparing it with the voltage 102, and a filter 38 smoothes this constant time pulse to generate a rotation speed voltage 100.

51 and 52 are connected in series with each other and connected between the output terminal and the inverting input terminal of the operational amplifier 6, and together with the operational amplifier 6 and the resistor 4, the rotation speed voltage 10
These resistors and capacitors constitute an integrating circuit that time-integrates the difference between 0 and the set voltage 200.

Next, the operation will be explained. The output of the signal generator 2, which is generated at a frequency proportional to the engine speed, is shaped into a square wave pulse 101 by a waveform shaper 31. Capacitor 32 receives this pulse 101
is differentiated, and the transistor 34 is turned on for a very short time. When transistor 34 turns on, capacitor 36 discharges and a progressive waveform (sawtooth waveform) 40
0 becomes 0. When transistor 34 turns off after the differential time, capacitor 36 charges through resistor 35 and ramping waveform 400 rises over time. The comparator 37 compares the constant voltage 102 with the gradually increasing waveform 400, and outputs a pulse 103 at L'' level for a certain period of time.
Output. Filter 38 converts this pulse 103 into rotational speed voltage 100. This rotation speed voltage 1
00 decreases in proportion to the rotation speed. Now, when adjusting the variable resistor 7 to lower the set voltage 200 (increase the target rotation speed), the comparison voltage 300 gradually increases by integrating the deviation voltage from the rotation speed voltage 100 in the decreasing direction.
decreases, the duty of the drive pulse 500 increases, the actuator 12 operates, and the rotational speed of the engine 1 increases. When the rotation speed increases, the rotation voltage increases to 100
decreases. While the rotational voltage 100 is higher than the set voltage 200, the comparison voltage 300 continues to decrease, the duty of the drive pulse 500 increases, and the rotational speed of the engine 1 increases. Conversely, when the rotational voltage 100 becomes smaller than the set voltage 200, the comparison voltage 300 continues to rise due to integration in the upward direction, the duty of the drive pulse 500 decreases, and the rotational speed of the engine 1 decreases. Due to this operation, when the rotational voltage 100 and the set voltage 200 match, the comparison voltage 300
changes stop and become stable. Therefore, the rotation speed-negative pressure characteristic becomes as shown in FIG. 4, and there is no change in rotation speed due to a change in load torque.

The above has been explained in a steady state or when the load or set voltage 200 is slowly changed, but when the load or the like suddenly changes, a difference occurs between the rotational speed and the set rotational speed, and this gradually decreases. It takes some time until these match. This response time is due to resistor 4 and capacitor 52;
Increasing the capacitor 52 improves steady-state stability, but increases response time. vice versa,
If the resistor 4 and capacitor 52 are made small, the response time will be shortened, but the steady state stability will be deteriorated.
The resistor 51 functions to improve both stability and responsiveness, which are contradictory. In other words, when a difference occurs between the rotation speed voltage 100 and the set voltage 200, a current proportional to this difference flows through the resistor 4, and all of this current also flows through the resistor 51, so the comparison voltage 300 is the product of this current and the resistor 51. It changes suddenly by the amount of time, improving responsiveness. In steady state, the rotational speed voltage 1
The difference between 00 and the set voltage 200 is 0, and the resistance 4
No current flows through the resistor 51, so no current flows through the resistor 51, and the comparison voltage 300 is not affected by the resistor 51. As described above, by inserting the resistor 51, responsiveness can be improved without impairing stability.

Also, according to this embodiment, a gradually increasing waveform (sawtooth waveform)
400, the voltage of the capacitor 36 inside the fV converter 3 is used, and the repetition period of the sawtooth wave corresponds to the engine rotation period, so that the response can be further improved. That is, FIG. 5 shows waveforms of various parts of the embodiment in FIG. 3, and the explanation will be made using these waveforms.
In a steady state, the period of the falling portion 402 of the gradually increasing waveform 400 is constant, and the driving time of the driving pulse 500 is PW2. Now, if the load on the engine suddenly becomes lighter and the rotational speed suddenly increases, the falling part of the gradual increase waveform 400 becomes 401, and the driving time becomes
PW suddenly decreases to 1, suppressing the rapid increase in rotational speed, and conversely, the load on the engine increases rapidly and the rotational speed suddenly decreases, the falling part of the gradual increase waveform 400 becomes 403, the driving time rapidly increases to PW3, and the rotational speed suddenly decreases. suppress. Therefore, the responsiveness to sudden changes in engine load is further improved.

As described above, according to the present invention, it is possible to realize an excellent speed governor in which responsiveness is improved without impairing stability, and there is no change in rotational speed due to load.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional speed governor, Fig. 2 is a characteristic diagram of the conventional device shown in Fig. 1, Fig. 3 is a circuit diagram showing an embodiment of the present invention, and Fig. 4 is a diagram showing the implementation of Fig. 3. An example characteristic diagram, FIG. 5, is an explanatory diagram of the operation of the embodiment of FIG. 3. 1 is an engine, 2 is a signal generator, 3 is an f-V converter, 4, 10, 33, 35, 51 are resistors, 6 is an operational amplifier, 7 is a variable resistor, 9, 37 are comparators,
11 and 34 are transistors, 12 is an actuator, 32, 36, and 52 are capacitors, 31 is a waveform shaper, and 38 is a filter. Note that the same reference numerals in the drawings indicate corresponding parts.

Claims (1)

[Claims] 1. A rotation signal generating means for generating a rotation signal with a frequency proportional to the rotation speed of the engine, a means for generating a triangular wave signal whose magnitude repeatedly changes over time in synchronization with the rotation signal, and a means for generating a triangular wave signal whose amplitude repeatedly changes over time. a first comparing means for generating a pulse output with a duty corresponding to the number of revolutions by comparing them, and smoothing the output pulses of the first comparing means to generate a number of revolutions detection output having a magnitude corresponding to the number of revolutions. a smoothing means, a speed setting means for generating a set output corresponding to the set rotational speed, an integrating means for integrating the deviation between the rotational speed detection output and the set output, and comparing the output of the integrating means with the triangular wave signal. A speed governor comprising: a second comparing means that generates a pulse output according to the magnitude; and an actuator that adjusts the rotation speed of the engine according to the pulse output of the second comparing means.