JP2001207899A - Electronic governor device for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control an engine speed of an engine so as to be held at a preset engine speed without using an expensive rack position sensor for detecting a position of a control rack and without exhausting black smoke from the engine. SOLUTION: A signal converting means 7A is arranged for restricting a rate of change of time of an engine speed setting signal, and a deviation signal (e) is obtained by arithmetically operating a deviation between a preset engine speed and an actual engine speed from an engine speed setting signal (b) and an engine speed detecting signal (c) restricted on the rate of change of time. A manipulated variable of the control rack 2a required to zero the deviation between the engine speed setting signal (b) and the engine speed detecting signal (c) restricted on the rate of change of time is arithmetically operated by a manipulated variable arithmetically operating means 7D, and a driving signal (h) is imparted to an actuator 4 so as to displace the control rack 2a by the arithmetically operated manipulated variable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the position of a control rack of a fuel injection pump in accordance with a deviation between an actual rotational speed and a set rotational speed so as to keep the rotational speed of a diesel engine at the set rotational speed. The present invention relates to an electronic governor device for a diesel engine which is controlled in a controlled manner.

[0002]

2. Description of the Related Art Conventionally, like a generator or a compressor,
2. Description of the Related Art In a diesel engine that drives a load that operates at a set rotation speed, an electronic governor device is provided to maintain the rotation speed at the set rotation speed.

[0003] An electronic governor device for a diesel engine includes an actuator for operating a control rack for adjusting the injection amount of a fuel injection pump for supplying fuel to the diesel engine, and a voltage signal containing information on the actual rotational speed of the diesel engine. The engine includes a rotation speed detector that outputs a detection signal, and a rotation speed setting device that outputs a voltage signal indicating a set rotation speed of the diesel engine as a rotation speed setting signal.

Further, the electronic governor device for a diesel engine includes a deviation calculating section for calculating a deviation between an actual rotation speed of the engine given by a rotation speed detection signal and a set rotation speed given by a rotation speed setting signal, And an actuator drive unit that drives an actuator to displace the control rack by the operation amount calculated by the operation amount calculation unit. Have.

In a diesel engine, the permissible limit position of the control rack (permissible limit value of the fuel injection amount) at each rotation speed is predetermined, and when the control rack is displaced to a position beyond the permissible limit position (fuel If the injection amount exceeds the permissible limit value), the engine may not only emit black smoke, but also damage the engine in some cases.

Therefore, in an electronic governor device for a diesel engine, a rack position sensor including a potentiometer or the like for detecting the position of the control rack is provided, and the position of the control rack detected by the rack position sensor is set at an allowable limit at each rotation speed. The control is performed so as not to exceed the position.

[0007]

As described above, in a conventional electronic governor for a diesel engine, a rack position sensor is used to control the position of the control rack so as not to exceed an allowable limit position at each rotation speed. I needed to. In this case, as the rack position sensor,
It is necessary to use a highly durable one that operates stably for a long period of time. Therefore, the rack position sensor is relatively expensive, and as a result, there is a problem that the cost of the governor device is increased.

Further, in the conventional electronic governor device, when the set rotational speed changes suddenly, the engine is suddenly accelerated and decelerated to generate a loud noise from the engine.
Surrounding people could be surprised or uncomfortable. For example, when a compressor of a refrigerator car is driven by a diesel engine, the number of rotations of the compressor is controlled so as to maintain the temperature in the refrigerator at a set value. When the number is changed, the engine transiently enters a sudden acceleration / deceleration state, generating a loud noise, which may give the driver discomfort. In particular, when the set number of revolutions is changed and the engine emits a loud noise while the driver is taking a nap, the driver may be overlooked, which is not preferable.

An object of the present invention is to maintain the engine speed at a set speed without using an expensive rack position sensor for detecting the position of the control rack and without discharging black smoke from the engine. It is to provide an electronic governor device for a diesel engine that can be controlled.

Another object of the present invention is to provide an electronic governor device for a diesel engine which can prevent generation of a loud noise when the set speed is changed and the engine is rapidly accelerated or decelerated. Is to do.

[0011]

SUMMARY OF THE INVENTION The present invention provides an actuator for operating a control rack of a fuel injection pump for supplying fuel to a diesel engine, and a voltage signal containing information on the actual rotational speed of the diesel engine as a rotational speed detection signal. A rotational speed detecting means for outputting, a rotational speed setting means for outputting a voltage signal for giving a set rotational speed of the diesel engine as a rotational speed setting signal, and an actual rotational speed and a rotational speed setting signal of the engine given by the rotational speed detection signal. A deviation calculating means for calculating a deviation from a given set rotational speed, an operation amount calculating means for calculating an operation amount of the control rack required to reduce the deviation to zero, and an operation amount calculated by the operation amount calculating means An actuator driving means for driving an actuator to displace the control rack. Target electronic governor for Le engines.

According to the present invention, there is provided signal conversion means for limiting a temporal change rate of an output signal when an input signal changes to a predetermined limit value or less. It was configured to input. The deviation calculation means calculates a deviation from the output of the signal conversion means and the rotation speed detection signal output by the rotation speed detection means.

It is preferable that the signal conversion means is configured to change a limit value of a temporal change rate of an output signal in accordance with a type of a load of the diesel engine.

As described above, the rotation speed setting signal output from the rotation speed setting device is supplied to the signal conversion means, so that the time change rate is converted into a rotation speed setting signal limited to a predetermined limit value or less. Then, when the actuator that operates the control rack is controlled so that the deviation between the rotation speed setting signal and the rotation speed detection signal whose time rate of change is limited is zero, the position of the control rack is detected using the rack position sensor. By simply setting the limit value of the time rate of change of the rotation speed setting signal to an appropriate value without controlling the control rack, when the set rotation speed is changed, the control rack displaces beyond the allowable limit position. Can be prevented.

Therefore, according to the present invention, it is possible to control to keep the engine speed at the set speed without using an expensive rack position sensor and without discharging black smoke from the engine.

As described above, when the actuator that operates the control rack is controlled so that the deviation between the rotation speed setting signal and the rotation speed detection signal whose time rate of change is limited is zero, the set rotation speed is changed. When the set rotation speed is changed, it is possible to prevent a loud noise from being generated from the engine because it is possible to prevent the engine from being suddenly accelerated or decelerated when the engine speed is changed.

[0017]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a configuration example of an electronic governor device for a diesel engine according to the present invention. In the figure, reference numeral 1 denotes a diesel engine to be controlled;
Denotes a fuel injection pump that supplies fuel to the diesel engine 1, and 3 denotes an engine load (such as a generator or a refrigerator).

The fuel injection pump 2 is a control rack 2
a, the amount of fuel supplied to the engine 1 can be adjusted by adjusting the position of the control rack 2a.

Reference numeral 4 denotes an electric actuator for operating the control rack 2a of the fuel injection pump by using a motor or an electromagnet as a drive source. This actuator has an amount corresponding to the applied drive current.
Is displaced.

Reference numeral 5 denotes a rotation speed detector which detects the rotation of the engine 1 and outputs a pulse signal f having a frequency proportional to the actual rotation speed of the engine 1. Reference numeral 6 denotes a rotation speed setting signal which gives a set rotation speed of the engine 1. This is a rotation number setting device that outputs a.

The rotational speed setting unit 6 is provided with a rotational speed setting signal a for giving a set value of the rotational speed according to the type of the load and the operating state.
Is output. In the illustrated example, the rotation number setting device 6 is set to 100
A voltage signal indicating a change of 1 V per 0 [rpm] is output as a rotation speed setting signal a. When the load 3 is operated at a constant rotational speed, the rotational speed setting signal output from the rotational speed setting device 6 is kept constant during the operation of the engine. As in a certain case, when it is necessary to appropriately change the rotation speed depending on the load condition, the rotation speed setting signal a is changed according to the load condition.

Reference numeral 7 denotes a controller, which comprises a signal conversion means 7A, a frequency / voltage converter 7B,
It comprises a deviation calculating means 7C, an operation amount calculating means 7D, an actuator driving means 7E, and a fail-safe means 7F.

The signal converting means 7A is provided especially in the present invention. The signal converting means 7A receives the rotational speed setting signal a as an input signal, and sets a predetermined change rate of a time change rate of the output signal when the input signal changes. It has the following functions. The signal converting means 7A limits the temporal change rate of the input signal (rotational speed setting signal a) so as to limit the amount of change of the set rotational speed per second to 150 [rpm] or less, for example, to 1000
A rotation speed setting signal b whose output changes at 1 [V] per [rpm] and whose temporal change rate is limited to 150 [rpm] / sec or less is output.

The frequency / voltage converter 7B converts the frequency of the output signal f of the rotation speed detector 5 into a voltage signal and outputs a rotation speed detection signal c that gives the actual rotation speed of the engine. In the illustrated example, the rotation number detection signal c shows a change of 1 [V] per 1000 [rpm], similarly to the rotation number setting signal.

The deviation calculating means 7C is composed of a subtractor. The rotational speed detection signal c supplied from the frequency / voltage converter 7B and the rotational speed setting output from the signal converting means 7A have a limited temporal change rate. Using the signal b as an input, a deviation between the actual rotational speed and the set rotational speed is calculated.

The operation amount calculating means 7D is provided with a deviation calculating means 7C.
To calculate the operation amount of the actuator 4 (equal to the operation amount of the control rack 2a) necessary to make the deviation zero by using the deviation signal e output from the controller as an input, and displace the actuator 4 by the calculated operation amount. A control signal g is given to the actuator driving means 7E so that the actuator driving means 7E outputs a driving signal h which needs to be given to the actuator.

The manipulated variable calculating means 7D shown in FIG.
To perform a proportional operation (P operation) to output a proportional control signal p, and an integral operation unit 70 to perform an integral operation (I operation) on the deviation signal e and output an integral control signal i.
2, a differential calculator 703 that performs a differential operation (D operation) on the deviation signal e to output a differential control signal d, and subtracts the differential control signal d from the sum of the proportional control signal p and the integral control signal i. , An adder / subtractor 704 that outputs a PID control signal g that gives the amount of operation of the control rack necessary to match the actual engine speed to the set engine speed.

The actuator driving means 7E includes a PI
A switching means 705 controlled by a D control signal g, and a switching means 70 controlled by the PID control signal g.
5 is turned on / off to control the operation amount calculating means 7D.
The drive signal h is supplied to the actuator 4 so that the actuator 4 (control rack 2a) is displaced by the operation amount calculated by the following. The drive signal h of the actuator 4 may be a voltage or a current.

The fail-safe means 7F sets the drive signal h input to the actuator 4 to zero when the rotation speed of the engine 1 exceeds the limit value or when the engine 1 is stalled due to overload or the like. And the actuator driving means 7E.

In the illustrated example, the rotational speed detector 5 and the frequency / voltage converter 7B constitute a rotational speed detecting means.

The diesel engine 1 outputs a predetermined torque according to the fuel supply amount determined by the position of the control rack 2a. The rotation speed of the engine 1 rises or falls depending on the relationship between the output torque and the load torque.

In the electronic governor device shown in FIG.
The deviation between the actual rotation speed of the engine and the set rotation speed is calculated by the deviation calculation means 7C, and the operation amount calculation means 7D calculates the operation amount of the control rack 2a required to reduce the deviation to zero. The actuator driving means 7E is
With the PID control signal g output from the operation amount calculation means 7D as an input, a drive signal h is given to the actuator drive means 7E to displace the control rack 2a by the calculated operation amount.

The actuator 4 is configured to operate a control rack using a solenoid or an electric motor as a drive source, and adjusts the amount of fuel supplied to the engine 1 by displacing the control rack 2a by a calculated operation amount. By doing so, the output torque of the engine 1 is made to converge to a value equal to the load torque, and the fluctuated engine speed matches the set engine speed.

FIG. 2 shows the relationship between the engine speed N and the position (rack position) L of the control rack. The broken line OABC in FIG. 2 indicates the rack at each speed. The allowable limit position of the position is shown. When the rack position L exceeds the permissible limit position at each rotation speed and enters a region (black smoke generation region) indicated by hatching in FIG. 2, black smoke is generated from the engine 1, and in some cases, the engine is stopped. fall into disrepair.

Point A in FIG. 2 shows a rack position where the maximum torque is generated (maximum torque rack position). In the region where the rotation speed is low, the allowable limit position of the rack position L has reached the black smoke generation region. However, due to the characteristics of the diesel engine, the fuel injection amount necessary to start rotation at startup is the maximum torque. This is because the start position increase control (control for increasing the fuel supply amount at the start) is performed because the position becomes larger than the rack position A. In FIG. 2, a two-dot chain line including SG indicates a rack position necessary for maintaining rotation when no load is applied.

FIG. 3 shows the relationship between the number of revolutions N of the engine and the output torque T of the engine. According to the relationship shown in FIG. 2, the engine speed N is equal to the rack position L.
Therefore, the output torque T at each rotation speed is also determined by the rack position L.

The point C 'in FIG. 3 is a point where the rated torque is generated (rated torque point), and corresponds to the point C in FIG.
Now, let us consider a case where the motor is operating at the point G 'with no rotation at no load. When the load torque increases from this state, the operating point approaches the point C '. However, if the load torque is within the rated torque, the operating point is on the G'-C' line, and the rotation speed becomes No can be maintained. When the control for limiting the rack position is performed, when a load greater than the point C 'is applied, the operating point moves on the line C'-B'-A' and the output torque decreases while the rotation speed decreases. Rises.

When the load 3 of the engine 1 is a working machine such as a compressor or a generator, the rated torque of the load is smaller than the rated output torque of the engine. , The operating point does not exceed the C 'point.

However, when the load needs to change the rotation speed of the engine 1, the operating point is C 'in FIG.
It may exceed the point (point C in FIG. 2).

For example, in FIG. 2, the operating point is the point S during the no-load operation at the rotation speed N1, but when the rotation speed is switched to No from this state, the operating point becomes
Move to the point G along the locus (1) shown in (1), the vehicle enters the black smoke generation area on the way, and black smoke is generated from the engine. Further, since high torque is generated before reaching point G, the acceleration of the engine increases, and in some cases, the engine and the load may be damaged.

When control is performed so that the rack position does not exceed the allowable limit position, the operating point moves along the locus (2) shown in FIG. There is no. Conventionally, a rack position sensor for detecting a rack position L is provided in order to limit the rack position to an allowable limit position or less, and the rack position is controlled so as not to exceed the O-A-B-C line in FIG. However, as described above, it was necessary to use an expensive rack position sensor having high durability, so that the cost of the governor was unavoidably increased.

Therefore, in the present invention, the signal conversion means 7A is inserted between the rotation speed setting device 6 and the deviation calculation means 7C to limit the upper limit of the rate of change of the rotation speed setting signal per unit time. The rotational speed setting signal b, whose time rate of change is limited by the signal converting means, is inputted to the deviation calculating means 7C.

With this configuration, the set rotation speed is set to N1
When changing from No to No, the operating point can be moved from point S to point G along the locus (3) in FIG.
The rotational speed of the engine can be set to No by displacing the rack position L in the fuel injection amount increasing side without entering the black smoke generating region.

As described above, when the deviation is calculated from the rotation speed setting signal and the rotation speed detection signal whose time rate of change is limited, when the set rotation speed is changed from N1 to No, Since the operating point can be moved from the point S to the point G while limiting the acceleration of the engine, it is possible to prevent the engine from suddenly accelerating and decelerating and generating a loud noise.

In the above example, the signal conversion means 7A
The time rate of change of the rotation speed setting signal is 150 [rpm] per second.
Although the restriction is made below, it goes without saying that the limit value of the temporal change rate by the signal conversion means 7A is not limited to 150 [rpm] / sec. Signal conversion means 7A
The limiting value of the rate of change of the signal over time is set so that when the set value of the number of revolutions is changed, the acceleration of the engine is within the range where the rack position does not enter the black smoke generation area and the engine operation noise does not become excessive. May be set to an appropriate value in accordance with the characteristics of the engine and the load so that the operating point can be moved while limiting the operation. Therefore, it is preferable that the signal conversion means 7A be configured so as to be able to change the limit value of the temporal change rate of the output signal according to the type of the load (the type of the working machine) of the diesel engine 1.

In the controller 7 shown in FIG. 1, the signal conversion means 7A may be constituted by an analog circuit, or may be constituted by causing a microcomputer to execute a predetermined program.

FIG. 4 shows an example of the signal conversion means 7A constituted by an analog circuit. In FIG. 4, CM1 is a comparator, OP1 and OP2 are first and second operational amplifiers, respectively, R1 through R4, Rs1, Rf1, Rs2, Rf2 and Ri1 are fixed resistors, Ri2 is a semi-fixed resistor, and C1 is an integrating capacitor. It is.

The non-inverting input terminal of the comparator CM1 is supplied with the rotation speed setting signal Vin, and the output voltage Vi is fed back to the inverting input terminal of the comparator. The output terminal of the comparator CM1 is connected through a resistor R1 to the positive terminal of a DC power supply having an output voltage E, and a power supply voltage E is applied to both ends of a series circuit of resistors R2 and R3.

In the signal converting means shown in FIG. 4, an integrating circuit 710 is constituted by an integrating capacitor C1 and a current limiting resistor Ri composed of a series circuit of resistors Ri1 and Ri2. The voltage Vi across the integrating capacitor C1 is output through a voltage follower circuit 711 comprising an operational amplifier OP2, and the voltage Vi output from the voltage follower circuit 711 is used as the rotation speed setting signal shown in FIG. Used as b.

Although not shown, a circuit is provided for initially charging the integrating capacitor C1 to a voltage value corresponding to the idling speed of the engine when the power is turned on at the time of starting the engine. This is because the start value of the engine is set to the idling rotation speed without delay at the start of the start of the engine to facilitate the start of the engine.

The non-inverting input terminal of the comparator CM1 is an input terminal of the signal conversion means 7A, and the rotation speed setting signal a output from the rotation speed setting device 6 is input to this input terminal. In FIG. 4, the rotation speed setting signal a is shown as a voltage Vin for convenience.

The inverting input terminal of the comparator CM1 is connected to the output terminal of the voltage follower circuit 711.

In the circuit shown in FIG. 4, the comparator CM
1 and a resistor R1 and a DC power supply (not shown) that outputs a DC constant voltage E. The input voltage Vin and the output voltage Vi are compared, and when the input voltage Vin is higher than the output voltage Vi, the first
And an input / output comparison circuit 712 that outputs zero when the input voltage Vin is lower than the output voltage Vi, and outputs the voltage Vc (equal to the power supply voltage E). The resistors R2 and R3
And a DC power supply (not shown) constitute a 1/2 voltage generating circuit 713 for outputting a second voltage Vd having a magnitude half of the first voltage Vc.

The positive input terminal of the operational amplifier OP1 is a resistor R
It is connected to the output terminal of the comparator CM1 through s1 and to the output terminal of the voltage follower circuit 711 through the resistor Rf1. The opposite-phase input terminal of the operational amplifier OP1 is connected to a connection point between the resistors R2 and R3 through a resistor Rs2, and the operational amplifier OP1 is connected through a resistor Rf2.
It is connected to the output terminal of P2. In this example, the operational amplifier OP1 and the resistors Rs1, Rf1, Rs2 and Rf2 form
An addition / subtraction circuit 714 is configured to perform an operation of adding the first voltage Vc to the output voltage Vi at a predetermined ratio A and an operation of subtracting the second voltage Vd from the output voltage Vi at the same ratio A. And the current limiting resistor R
Through i, the integration capacitor C1 is charged.

In the present invention, the resistances of the resistors Rs1 and Rs2 are larger than the resistances of the resistors Rf1 and Rf2, and the resistances of the resistors Rs1 and Rs2 are set equal. The resistance value is set equal, and the absolute value of the voltage Vo-Vi applied across the series circuit of the resistors Ri1 and Ri2 is always constant.
That is, the integration capacitor C1 is connected to the constant current i [= (Vo-Vi).
) / Ri], the circuit constants are set.

As in the example shown in FIG. 1, a specific example of the circuit constant of the circuit shown in FIG. 4 when the limit value of the temporal change rate of the set value of the rotational speed is 150 [rpm / sec] will be described. , R1
= 2.5 [KΩ], R2 = R3 = 2 [KΩ], Rs1 = R
s2 = 200 [KΩ], Rf1 = Rf2 = 7.5 [KΩ], R
i1 = 75 [KΩ], Ri2 = 50 [KΩ], R4 = 10
[KΩ], C1 = 11 [μF], and E = 8 [V].
R4 is a load resistance which can be set to an appropriate value.

In the circuit shown in FIG. 4, when the input voltage Vin is increased in order to increase the number of revolutions of the engine, the output terminal of the comparator CM1 becomes open with respect to the ground circuit. Is input to the operational amplifier OP1 through the resistors R1 and Rs1. The operational amplifier O
The output voltage Vi is input to P1 through a resistor Rf1, and the voltage Vd is input to a resistor Rs2.

At this time, the output Vo of the operational amplifier OP1 (the output of the addition / subtraction circuit 714) is given by the following equation, where rs is the resistance value of the resistors Rs1 and Rs2 and rf is the resistance value of the resistors Rf1 and Rf2.

Vo = Vi + (Vc−Vd) (rf / rs) (1) Here, since Vd is R2 = R3, Vd = E
/ 2 [V].

Therefore, Vo-Vi = (Vc-E / 2) (rf / rs) (2) When the input voltage Vin is increased in order to increase the engine speed, Vin is higher than Vi. Vc = E
Therefore, Vo-Vi = E (rf / rs) (3) The integrating capacitor C1 is charged with a constant current i obtained by dividing the voltage of the equation (3) by the resistance Ri, and both ends of the capacitor C1 are charged. The voltage Vi gradually increases.

Assuming that the capacitance of the capacitor C1 is c,
The voltage Vi is given by the following equation.

Vi = (1 / c) ∫ [(Vo−Vi) / Ri] dt (4) This voltage Vi passes through the voltage follower circuit 711 and deviates as a rotation speed setting signal b whose rate of change over time is limited. It is input to the calculating means 7C. The temporal change rate of the voltage Vi can be appropriately adjusted by adjusting the resistance value of the current limiting resistor Ri.

When the output voltage Vi becomes equal to the input voltage Vin, a state occurs in which the magnitude relationship between the voltage of the non-inverting input terminal and the voltage of the inverting input terminal of CM1 is switched at a predetermined cycle, and the comparator CM1 enters an oscillation state. Is the integrating capacitor C1
Is sufficiently longer than the oscillation cycle of the comparator CM1, so that the voltage Vi obtained across the integrating capacitor C1 is kept substantially constant.

When the input voltage Vin is decreased in order to decrease the number of revolutions of the engine, the output terminal of the comparator CM1 is grounded, so that Vc becomes zero. At this time, Vo−Vi in the equation (2) is as follows: Vo−Vi = −E (rf / rs) (5) Therefore, the integrating capacitor C1 discharges at a constant current, and the voltage Vi (rotational speed setting signal) across the capacitor C1 decreases at a constant rate.

As is clear from the above description, the signal conversion means 7A shown in FIG. 4 uses the input voltage Vin and the output voltage Vi
The input / output comparison circuit 712 outputs the first voltage Vc when the input voltage Vin is higher than the output voltage Vi, and sets the output voltage to zero when the input voltage Vin is lower than the output voltage Vi. And a second voltage having a half of the first voltage Vc.
A voltage generating circuit 713 that outputs the voltage Vd of the output voltage Vd, a calculation of adding the first voltage Vc to the output voltage Vi at a predetermined rate A, and the second rate Vd being calculated from the output voltage Vi by the same rate A.
An addition / subtraction circuit 714 for performing a subtraction operation, an integration circuit 710 for performing an integration operation by charging an integration capacitor C1 through a current limiting resistor Ri with an output voltage Vo of the addition / subtraction circuit 714, and a voltage across the integration capacitor C1. A voltage follower circuit 711 that outputs the output voltage Vi as an input. The adder / subtractor circuit 711 is configured such that the absolute value of the voltage Vo−Vi applied to both ends of the current limiting resistor Ri of the integration circuit is always constant. Is set.

To facilitate the start of the engine, it is preferable to provide a circuit for initially charging the integrating capacitor to a voltage value corresponding to the idling speed when the power is turned on, as described above.

[0068]

As described above, according to the present invention, the time change rate of the rotation speed setting signal is limited to a predetermined limit value or less, and the rotation speed setting signal whose time change rate is restricted is limited. The actuator that operates the control rack is controlled so that the deviation between the rotation speed detection signal and the rotation speed detection signal becomes zero, so that the time of the rotation speed setting signal can be controlled without controlling the position of the control rack using a rack position sensor. By simply setting the limit value of the target change rate to an appropriate value, it is possible to prevent the control rack from being displaced beyond the allowable limit position when the set rotation speed is changed. Therefore, it is possible to control to keep the engine speed at the set speed without using an expensive rack position sensor and without discharging black smoke from the engine.

Further, according to the present invention, the actuator for operating the control rack is controlled so that the deviation between the rotation speed setting signal and the rotation speed detection signal whose time rate of change is limited is reduced to zero. When the engine speed is changed, it is possible to prevent the engine from suddenly accelerating and decelerating, thereby preventing a loud noise from being generated from the engine.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of an electronic governor device for a diesel engine according to the present invention.

FIG. 2 is a diagram showing a relationship between a rack position and a rotation speed of a diesel engine.

FIG. 3 is a diagram showing a relationship between output torque and rotation speed of a diesel engine.

FIG. 4 is a circuit diagram illustrating a configuration example of a signal conversion unit used in the governor device of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Diesel engine, 2 ... Fuel injection pump, 3 ... Load, 4 ... Actuator, 5 ... Rotation speed detector, 6 ... Rotation speed setting device, 7 ... Controller, 7A ... Signal conversion means, 7
B: frequency / voltage converter, 7C: deviation calculating means, 7D:
Operation amount calculation means, 7E ... actuator drive means.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 3G060 AA07 AA08 AB01 AC08 BA02 CA01 CB04 CB05 CC08 DA01 DA13 FA06 GA00 GA03 3G084 AA01 AA06 BA03 BA13 DA10 DA13 EB12 EC03 FA13 FA33 3G301 HA02 HA27 JA04 JA20 JA24 LB14 ND01 PE01A

Claims (2)

[Claims] 1. An actuator for operating a control rack of a fuel injection pump for supplying fuel to a diesel engine, and a rotation speed detecting means for outputting a voltage signal including information on an actual rotation speed of the diesel engine as a rotation speed detection signal. Rotation speed setting means for outputting, as a rotation speed setting signal, a voltage signal that gives a setting rotation speed of the diesel engine; an actual engine speed given by the rotation speed detection signal; and a setting rotation given by the rotation speed setting signal. A deviation calculating means for calculating a deviation from the number, an operation amount calculating means for calculating an operation amount of the control rack required to make the deviation zero, and an operation amount calculated by the operation amount calculating means. Actuator driving means for driving the actuator so as to displace the control rack. In an electronic governor device for a diesel engine, the time change rate of the output signal when the input signal changes is
A signal conversion unit for limiting the rotation speed to a predetermined value or less is provided, and the rotation speed setting signal is input to the signal conversion unit. The deviation calculation unit includes an output of the signal conversion unit and the rotation speed detection unit. An electronic governor device for a diesel engine, wherein the deviation is calculated from a rotational speed detection signal to be output. 2. The apparatus according to claim 1, wherein the signal conversion unit is configured to change a limit value of a temporal change rate of the output signal according to a type of a load of the diesel engine. An electronic governor device for a diesel engine according to claim 1.