JPH03156144A - Engine speed control device - Google Patents

Abstract

PURPOSE:To continue an operating state of extracting an engine output power to the utmost extent in an overload condition by a method wherein an engine overload detection signal is output to reduce the engine load when the engine speed is not increased even in a state of the maximum fuel injection. CONSTITUTION:When a revolution judging means 19 does not detect that a revolution number is increasing, though it is detected that a fuel injection quantity control mechanism 9 is at the maximum fuel injection position, an engine 2 is judged to be in an overload operating condition and an overload signal is output to thereby reduce the engine load. According to this method, a considerable decrease of the engine speed and the accompanying engine output decrease are prevented. When a generator 4 is the load to the engine, the overload detection signal decreases an output voltage of an automatic voltage regulator 22 of the generator, the engine speed thereby maintains a specified value and the output cycle of the generator is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotation speed control device when an engine is in an overload operating state.

(Prior art) Proportional, integral, and differential (PID) calculations are performed on the voltage (deviation) for the difference between the actual engine speed and the target engine speed, and the fuel injection amount is adjusted based on the calculated output. Techniques for controlling engine speed are known.

FIG. 6 is a block diagram showing a conventional control system.

The rotation speed of the engine 100 is determined by detecting the rotation of a gear 102 provided on the output shaft 101 with a non-contact engine rotation sensor 103, generating a pulse signal Pn with a period corresponding to the rotation speed, and converting this signal Pn into a frequency - A voltage converter (f-V converter) 104 converts it into a corresponding analog voltage en.

PT is the deviation Δe between this voltage en and the voltage es corresponding to the target rotation speed given by the target rotation speed setting means 105.
The signal is input to the D calculation circuit 106, subjected to proportional, integral, and differential calculations by a proportional amplifier circuit 107, an integral circuit 108, and a differential circuit 109, respectively, and then applied to a fuel injection device 110 to adjust the fuel injection amount to control the engine 100. The rotation speed is controlled.

(Problem to be Solved by the Invention) In a device that performs this type of feedback control, the fuel injection mechanism (actuator) is driven to roughly increase the fuel injection amount as the engine load increases, but when the maximum injection It cannot handle engine overload that exceeds the position. In such an overload operating state, the engine speed will decrease. This decrease in rotational speed is accompanied by a decrease in engine output, which may further reduce the driving force of the load or even cause a stall.

For example, when driving a synchronous generator that generates commercial frequency power as a load, if a load such as a mercury lamp or an electric motor that temporarily flows a large current at startup is connected to the output side of the generator, the generator itself will The load becomes temporarily heavy, causing the engine to run under load. When the engine speed decreases due to this overload, the engine power, that is, the output power of the generator, also decreases, and even though it is a temporary overload, it takes time for the equipment to return to normal operation. Also, during this period, the output frequency of the generator also decreases.

Therefore, the present invention detects that the fuel injection amount adjustment mechanism is at approximately the maximum injection position in order to prevent a significant decrease in engine speed and an accompanying decrease in engine output in an overload operating state of the engine. If the engine speed determination means does not detect that the engine speed is increasing even though the engine speed is increasing, it is determined that the engine is in an overload operating state, and an overload detection signal is output. An object of the present invention is to provide an engine rotation speed control device that allows the maximum power of the engine to be utilized without reducing the engine rotation speed by controlling the load on the engine to be reduced using a load detection signal. purpose.

(Means for Solving the Problems) In order to solve the above-mentioned problems and achieve the objectives, an engine rotation speed control device according to the present invention provides a maximum fuel injection amount control system that detects that the fuel injection amount adjustment mechanism is at approximately the maximum injection position. The fuel injection amount adjustment mechanism is set to approximately the maximum injection position by the injection state detection means, the rotation speed determination means for determining whether the rotation speed detected by the rotation speed detection means is increasing, and the maximum fuel injection state detection means. If the rotation speed determining means does not detect that the rotation speed is rising at a certain speed or higher even though it is detected that the engine is in the engine!
1! I) is characterized in that it is configured to reduce the engine load by outputting to the load that is being

Note that the engine load is constituted by a generator, and the output setting voltage of the automatic voltage regulator of the generator may be controlled to be lowered by an overload signal.

(Function) The engine rotation speed control device does not detect that the rotation speed is increasing by the rotation speed determination means even though it is detected that the fuel injection amount adjustment mechanism is at the maximum fuel injection position. Sometimes, it is determined that the engine is in an overload operating state, and an overload detection signal is output, and this overload detection signal is used to reduce the load on the engine. This makes it possible to prevent a significant decrease in engine speed and an accompanying decrease in engine output.

If the engine load is a generator, the overload detection signal lowers the output voltage of the generator's automatic voltage regulator, so the engine rotation speed can be maintained at a predetermined rotation speed, and the generator output frequency is It becomes stable.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 is an overall system configuration diagram of an engine generator equipped with an engine rotation speed control device according to the present invention.

The engine generator 1 includes a rotation speed control device 3 that automatically controls the engine rotation speed by adjusting the amount of fuel supplied to the engine 2, and a generator 4 driven by the engine 2.

The rotation speed control device 3 inputs the voltage es corresponding to the target rotation speed set by the target rotation speed setting circuit 5 via a superimposition circuit 6 to one of the proportional/integral/differential calculation circuits (hereinafter referred to as PID circuits) 7. At the same time, the voltage is applied to the engine terminal 7a, and the engine 2
The voltage signal en corresponding to the actual rotational speed of is input to the other input terminal 7.
b, the difference voltage (es-en) between the two voltage signals
An output voltage eO is generated by performing proportional, integral, and differential calculations on the output voltage eO, and the solenoid actuator 9a of the fuel injection amount adjustment mechanism 9 is driven via a PWM (pulse width modulation) conversion circuit 8 to increase or decrease the fuel injection amount. , and is configured to control the rotation speed of the engine 2.

The rotational speed detection means 10 outputs a pulse signal Pn with a period proportional to the engine rotational speed, and this pulse signal Pn is converted by a frequency-voltage conversion circuit 11 into an analog voltage en corresponding to the period of the pulse signal Pn.

The position of the solenoid actuator 9a is detected by an actuator position sensor 12, and its position detection output 12
a is converted into a DC signal ea by a detection/rectification circuit 13.

The DC signal ea is amplified by a non-inverting amplifier circuit 14, and its output 14a is inputted to a non-inverting input terminal 6b of an operational amplifier 6d in the superimposing circuit 6 via a capacitor 6a.

FIG. 2 is a structural diagram showing an example of the configuration of a solenoid actuator and an actuator position sensor.

FIG. 2 shows an example of driving the control rack 9b of the fuel injection amount adjustment mechanism 9 for a diesel engine.
One end of a solenoid actuator 9a fixed to the side of the fuel injection amount adjustment mechanism 9 is connected to a control rack 9b, and a position sensor 12 using a differential transformer is further provided on the side of the solenoid actuator 9a.

The solenoid actuator 9a moves the actuator 9d in the axial direction by electromagnetic force by energizing the solenoid 9c. The position sensor 12 is a linear displacement sensor in which a movable core 12e is inserted into a primary coil 12b and secondary coils 12c, 12d. This sensor 12 is activated by exciting the primary coil 12b with a low-frequency alternating current to activate the movable core 1 connected to the actuator 9d.
Depending on the position of 2e, the secondary coil 12c is connected with reverse polarity.
, 12d and the change in polarity is used to detect the position of the actuator.

Returning to FIG. 1, the explanation will be continued.

When the actuator position sensor 12 is located on the fuel injection amount increasing side based on the output 12a of the position sensor 12, the position detection output voltage aa becomes high. The output ea of the detection/rectification circuit 13 is DC amplified by a non-inverting amplifier circuit 14, and a voltage corresponding to a change in the actuator position is differentiated through a differentiating circuit consisting of a capacitor 6a and a resistor 6C, and then sent to a non-inverting input terminal 6b of an operational amplifier 6d. is input to. The output voltage eO of the target rotation speed setting circuit 5 is applied to the non-inverting input terminal 6e of the operational amplifier 6d. When the differential input terminal is not applied to the non-inverting input terminal 6b, the output voltage of the superimposition circuit 6 is the same as the voltage of es, and when the actuator position moves to the fuel increasing side, the input from the differential circuits 6a and 6c causes The output voltage of the superimposing circuit 6 is lower than the voltage es, and is configured to be higher than the voltage es when moving to the fuel depletion side.

The PID circuit 7 includes an operational amplifier 7C and this operational amplifier 7.
An integrating circuit 15 provided between the output terminal 7d of the C and the inverting input terminal 7e, an input resistor 16 having one end connected to the inverting input terminal 7e, and a differentiating circuit 17 connected in parallel with this input resistor. It constitutes an arithmetic circuit. The integrating circuit 15 is
It is composed of three elements including a series circuit of a capacitor 15a, a capacitor 15b connected in parallel to the capacitor 15a, and a resistor 15c. The differentiating circuit 17 is composed of a series circuit of a capacitor 17a and a resistor 17b.

The output ea of the detection/rectification circuit 13 is applied from the input terminal 18a of the maximum fuel injection state detection means 18 to the manual input terminal 18e of the voltage comparator 18d via a time constant circuit consisting of a resistor 18b and a capacitor 18c. A reference voltage is applied from the reference voltage generation circuit 18g to one input terminal 18f of the voltage comparator 18d. This is the output voltage of the rectifier circuit 13. Therefore, when the maximum fuel injection state continues for a time constant determined by the resistor 18b and capacitor 18c, the output +8h of the detection means 18 becomes H level.

Note that the maximum fuel injection state may be detected by detecting that the solenoid actuator 9a has moved to a predetermined position using a limit switch or the like.

The output voltage en of the frequency-voltage conversion circuit 11 is applied to the input terminal 19a of the rotation speed determining means 19, and is inputted to one input terminal 19c of the voltage comparator 19d via the resistor 19b. One input terminal 19c of voltage comparator 19d and manual input terminal 1
A resistor 19f is connected between the resistor 9e and the resistor 9e. moreover,
The manual input terminal 19e is connected to a power supply +V via a resistor 19g, and is also connected to GND via a capacitor 19h. Therefore, when the output voltage en of the frequency-voltage conversion circuit 11 is rising with a predetermined time constant, the voltage at the - input terminal 19c is higher than the voltage at the manual input terminal t9e,
Output of voltage comparator 19d! 9i is at L level, but if the output voltage en maintains the same value for a predetermined time or decreases, the voltage at the manual input terminal 19e
c, the output 19i of the voltage comparator 19d
becomes H level.

The output 18h of the maximum fuel injection state detection means 18 and the output 19i of the rotation speed determination means 19 are each input to an AND circuit 20a in the engine overload control means 20, and the output drives a transistor 20c via a resistor 20b. It is configured like this. When the transistor 20c is turned on, a current is supplied via the resistor 3b through the path from the terminal 3c to the terminal 4a to the light emitting diode terminal 4b to the terminal 3a in the synchronous generator 4, and the engine 2 is supplied to the synchronous generator 4 side. Communicate that there is an overload condition.

The generator 4 is configured to reduce the output voltage of the power generation output terminals 4c and 4d to reduce the power supplied to the electrical load 21 upon receiving the engine overload signal.

FIG. 3 is a circuit diagram of the generator.

The generator 4 includes a winding section 22 and an output voltage adjustment circuit 23.

The winding portion 22 includes a field winding 2 wound on the rotor 22a side.
2b, an output winding 22C, a voltage detection winding 22d, and an excitation winding 22e provided on the stator side. The output winding 22c is connected to the power generation output terminals 4c and 4d.

The AC voltage generated in the excitation winding 22e is full-wave rectified by the diode bridge 24, smoothed by the capacitor 25,
A base current is supplied to the transistor 27 via the base resistor 26, and the transistor 27 is turned on to supply current to the field winding 22b.

The AC voltage generated in the voltage detection winding 122d is full-wave rectified by the diode bridge 28, and then connected to the resistor 29 and capacitor 3.
After smoothing with a smoothing circuit consisting of 0 so that the voltage waveform includes a pulsating component as shown in FIG. 4(a), the resistor 31,
The voltage is divided by a resistor 32, and this divided voltage is applied to the base of a transistor 34 via a Zener diode 33.

When the AC voltage generated in the voltage detection winding 22d is higher than a predetermined voltage value, the period during which the base current is supplied to the transistor 34 (the period indicated by diagonal lines in FIG. 4(a)) becomes longer, and the When the on-transistor 27 is turned off, the period during which the current supply to the field winding 21b is cut off becomes longer, and the generated output voltage decreases. In this way, by varying the current supply time to the field cap 21b, the output voltage eO generated between the power generation output terminals 4c and 4d is maintained at the rated value. Note that the diode 35 connected in parallel to the field winding 22b is a through-flow diode for absorbing a surge generated in the field winding 22b during the switching operation of the transistor 27.

A light emitting diode 36a, which is the primary side of the photocoupler 36, is interposed between the terminals 4a and 4b, and when the secondary side phototransistor 36b is turned on, the diode 37 - the food transistor 36b - the resistor 38 - the capacitor 39 are connected. A capacitor 39 is charged in the path, and this voltage is applied to the anode side of the Zener diode 33 via a diode 40 and a resistor 41. Therefore, Zener diode 3
As shown in FIG. 4(b), the voltage on the anode side of the generator 3 becomes smaller outside the ripple current, and the period during which the transistor 34 is driven in the on state becomes longer, so that the output voltage of the generator 4 decreases.

With the above configuration, if the electrical load 21 of the generator 4 exceeds the rating of the engine generator 1 and the rotational speed of the engine 2 decreases even if the fuel injection amount to the engine 2 is maximized,
The output of the engine overload control means 20 in the rotational speed control device 3 transmits a signal indicating an overload state to the output voltage adjustment circuit 23 on the generator 4 side, and the output voltage adjustment circuit 23
sets the generated output voltage to a value lower than the rated output voltage, so
The power supplied from the generator 4 to the electrical load 21 is reduced.

Therefore, the overload condition of the engine 2 is eliminated, the feedback control system of the rotation speed control device 3 returns to the normal operating state, and the engine 2 rotates at the target rotation speed, so the power generation frequency of the generator 4 is constant. is maintained.

FIG. 5 is a block diagram showing another example of the configuration of the engine speed control device.

In this embodiment, the voltage en corresponding to the actual rotation of the engine is
and inputting a voltage ea corresponding to the position of the actuator 9a to an analog-digital (A/D) converter 50,
The CPU 51 reads digital quantities corresponding to the rated voltages en and ea at predetermined time intervals, and when the preset conditions are met, sets the output port 51a to H.
The configuration is such that the transistor 20c is turned on via the resistor 20b. The CPU 51 determines that the maximum fuel injection state is present when the digital quantity corresponding to the voltage ea is equal to or larger than a preset value, for example, three times in a row, and the digital quantity corresponding to the voltage en is equal to or larger than the preset value. Alternatively, if the value decreases by more than a predetermined value from the value before the previous time, or if the digital quantity corresponding to the voltage en continues to decrease over a predetermined sampling line, it is determined that the engine speed is decreasing, and both The system is configured to determine that the engine is overloaded when the following conditions are met.

(Effects of the Invention) As explained above, the engine speed control device according to the present invention outputs an engine overload detection signal when the engine speed does not increase even in the maximum fuel injection state. Since the structure is designed to reduce the engine load, even if the engine is overloaded, the engine speed will not decrease and the engine output power can be obtained close to the maximum. It is possible to continue the operating state that maximizes the engine output power.

Further, since it is possible to utilize signals necessary for feedback control that are already included in the fuel injection control system, it is possible to realize a rotation speed control device with a simple configuration.

In addition, if the engine generator is used, the output setting voltage of the automatic voltage regulator is lowered based on the overload detection signal, and if the electrical load of the generator is heavy, that is, an overload condition occurs for the engine. The system is configured to limit the amount of power supplied to the electrical load, so even if a load that temporarily flows a large current, such as a mercury lamp or an electric motor, is connected as a generator load, the engine speed will not drop. It is possible to quickly return to steady operation by maximizing engine output, and since the rotational speed does not fluctuate, it is possible to maintain a stable power generation frequency when using a synchronous generator. .

[Brief explanation of the drawing]

Fig. 1 is an overall system configuration diagram of an engine generator equipped with an engine speed control device according to the present invention, Fig. 2 is a structural diagram showing an example of the configuration of a solenoid actuator and an actuator position sensor, and Fig. 3 is a power generation Figure 4 is a waveform diagram showing the voltage of the output detection winding in the output voltage adjustment circuit, Figure 5 is a block diagram showing another example of the configuration of the engine overload control means, and Figure 6 is a circuit diagram of the engine. is a block diagram of a conventional fuel injection amount control system. In addition, in the drawing, 1 is an engine generator, 2 is an engine, and 3
is a rotation speed control device, 4 is a generator, 5 is a target rotation speed setting circuit, 6 is a superimposition circuit, and 7 is a proportional/integral/differential circuit (PID).
circuit), 8 is a PWM conversion circuit, 9 is a fuel injection amount adjustment mechanism, 9a is a solenoid type actuator, 9C is a solenoid, 9d is an actuator, 10 is a rotation speed detection circuit, 1
1 is a frequency-voltage conversion circuit, 12 is an actuator position sensor, I8 is a maximum fuel injection state detection means, 19 is a rotation speed determination means, 20 is an engine overload control means, 21 is an electrical load of the generator, 22 is a winding Line part, 22a is rotor, 2
2b is a field winding, 22c is an output winding, 22d is a voltage detection winding, 22e is a wJ magnetic winding, 23 is an output voltage adjustment circuit, 36 is a photocoupler, 50 is an A/D converter, 51 is a c.
It is pu.

Claims (2)

[Claims] (1) a rotation speed detection means for detecting the rotation speed of the engine;
In an engine rotation speed control device that automatically controls the fuel injection amount by driving a fuel injection amount adjustment mechanism according to this output signal, the maximum fuel injection state detects that the fuel injection amount adjustment mechanism is at approximately the maximum injection position. A detection means, a rotation speed determination means for determining whether or not the rotation speed detected by the rotation speed detection means is increasing, and a maximum fuel injection state detection means, the fuel injection amount adjustment mechanism is set to a substantially maximum injection position. If the rotation speed determining means does not detect that the rotation speed is increasing at a certain speed or higher even though the rotation speed is detected to be at a certain speed, an overload detection signal is sent to the load being driven by the engine. 1. An engine rotation speed control device comprising: engine overload control means configured to reduce engine load by outputting engine overload control means. (2) The engine rotation speed control device according to claim 1, wherein the engine load is constituted by a generator, and the engine rotation speed control device is controlled to reduce the output setting voltage of an automatic voltage regulator of the generator based on an overload detection signal. .