JPH07279738A - Rotational speed control device for engine - Google Patents

Abstract

PURPOSE:To improve control accuracy and reliability by calculating an average rotational speed not influenced by any mis-pulse in pulsation cycle by means of an average rotational speed calculating unit, setting this average rotational speed as a real rotational speed, and controlling the rotational speed of an engine so as to eliminate any deviation between the real rotational speed and set rotational speed. CONSTITUTION:In a diesel engine used for a marine vessel and whose rotational speed is about 15 to 150rpm, a pulse generator for generating pulse per detection of the tooth part or the valley part of a turning gear in an engine is used as an engine rotational speed detector 1. A pulse signal P outputted from the pulse generator 1 is taken in a pulse/rotational speed converter 2, and engine rotational speed N is calculated. The engine rotational speed N is integrated 8 in an average rotational speed calculating unit 6 for a pulsation cycle which is calculated by a pulsation cycle calculating unit.setting unit 10, average rotational speed is calculated from integral values and times of integration, this average rotational speed is set as real rotational speed, and the rack position of a fuel pump is controlled according to a deviation between the real rotational speed and a set rotational speed by a setter 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational speed control device for an engine such as a diesel engine, and more particularly to a diesel engine having a rotational speed of about 15 rpm to 150 rpm used for ships.

[0002]

2. Description of the Related Art As a device of this type, Japanese Patent Publication No. 3-24
There is one disclosed in Japanese Patent No. 581. As is well known, in a diesel engine, output torque is obtained by injecting fuel corresponding to the fuel pump rack position at the fuel injection timing of each cylinder into the corresponding cylinder and causing the cylinder to explode.

In the diesel engine, since the output torque is obtained by the explosion due to the intermittent fuel injection, the output torque pulsates according to the rotation of the explosion. That is, in a 2-cylinder diesel engine with a Z cylinder (Z is the number of cylinders), if the rotational speed is N (RPM), the output torque pulsates at a cycle of 60 / N · Z (seconds), and 4 In the case of a cycle engine, assuming that the rotation speed is N (RPM), the output torque pulsates at a cycle of 120 / N · Z (seconds), and the engine rotation speed also pulsates at the same cycle. Therefore, no matter how the speed governor controls the amount of injected fuel, it is impossible to prevent the pulsation of the output torque, and the fuel pump rack is operated in response to the periodic change in the engine speed. However, since it is invalid except for the fuel injection timing, unnecessary operations are repeated.

In view of the characteristics of the diesel engine, the invention disclosed in Japanese Patent Publication No. 3-24581 has a structure in which it does not respond to the periodic fluctuation of the engine speed caused by the pulsation of the output torque. This is to prevent invalid operation of the fuel pump rack and control the average engine speed.

This prior art will be described with reference to FIG.

In FIG. 7, 102 is a diesel engine,
Reference numeral 103 is a power transmission shaft connected to the crankshaft of the diesel engine 102, and 104 is a propeller attached to the power transmission shaft 103. Further, 105 is an engine speed detector that outputs an engine speed signal, and 106 is a crank angle detector that outputs a crank angle signal.

Reference numeral 101 is a speed control device, which comprises an engine speed setting device 111, a synchronizing signal generator 115, a sample / hold circuit 114, a subtractor 112, and a control calculator 113.

The synchronizing signal generator 115 receives the above crank angle signal, and regarding the crank angle 0 ° to 360 °, 360 °
A timing signal is generated for each / Z and sent to the sample / hold circuit 114.

When the sample / hold circuit 114 receives the above timing signal, it samples the engine speed signal output from the engine speed detector 105 and outputs the sampled engine speed signal until the next timing signal is received. Hold.

The subtractor 112 is an engine speed setting device 111.
Calculates the difference between the engine speed setting signal output from the engine and the engine speed signal held by the sample / hold circuit 114, and outputs the difference as an engine speed deviation signal to the control calculator 113.
Output to.

The control calculator 113 performs control calculations such as proportional, integral, and derivative based on the engine speed deviation signal,
Obtain the fuel injection amount to be injected into the diesel engine 102,
The fuel injection amount signal is output to the fuel pump, and the rack (not shown) of the fuel pump is operated.

That is, the engine speed compared with the engine speed set value is the engine speed sampled and held at every 360 ° / Z.

Further, Japanese Patent Publication No. 3-24581 discloses a case where the number of pulses generated within a certain time ΔT from the generation of the timing signal is integrated and this integrated value is used as the engine speed.

[0014]

As the engine speed detector and the crank angle detector, a pulse generator is usually used, and the pulse generator is arranged close to a turning gear (not shown) of the diesel engine. A pulse is generated each time a tooth portion or a valley portion of the turning gear is detected. This pulse is counted to obtain the engine speed and the crank angle. Therefore, if a miss pulse due to a tooth breakage or the like occurs in the turning gear, a deviation occurs in the timing signal generation timing. This will be described with reference to FIG.

FIG. 8A shows the engine speed output by the engine speed detector 105, FIG. 8B shows the timing signal, and FIG. 8C shows the sample / hold circuit 114. Indicates the engine speed that the engine holds. When the actual rotation speed of the engine is constant, a miss pulse occurs, and the timing signal is generated at a time Δt (shown in (A) and (B) of FIG. 8) as compared with when there is no miss pulse. If it is deviated by just that, the engine speed sampled by the sample / hold circuit 114 changes as shown in FIG. 8C.

Further, the generation position of the timing signal is
Depending on the crank angle detector, the time point tB or the minimum pulsation value C at which the maximum pulsation value B of the pulsation rotation speed shown in FIG.
In some cases, even when the actual engine speed is constant, the sample / hold circuit 11
The engine speeds sampled by No. 4 are very different, which gives a feeling of strangeness to the ship operator.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide an engine speed control device capable of improving control accuracy and reliability as well as operating performance as compared with the prior art. To aim.

[0018]

In order to achieve the above-mentioned object, the present invention provides, in the invention of claim 1, a comparison operation between the engine speed in which the engine speed periodically pulsates and a set speed, and this comparison is made. In a rotation speed control device for an engine, which adjusts a fuel pump rack position of the engine based on a calculation result and adjusts a fuel injection amount to be supplied to the engine, (A) is arranged close to a turning gear that rotates together with rotation of the engine. A pulse generator that generates a pulse according to the rotation of the turning gear,
(B) A pulse / rotation speed converter that takes in the output of the pulse generator to calculate the engine speed, and (C) integrates the engine speed during the pulsation cycle calculated by the pulsation cycle calculation unit, (D) The pulsation cycle calculation unit has an average rotation speed calculation unit that calculates an average rotation speed from the integrated value and the number of times of integration, and next, based on the average rotation speed or the set rotation speed and the number of cylinders of the engine. The pulsation cycle is calculated, and (E) the average rotation speed is used as an engine rotation speed signal which is compared and calculated with the set rotation speed signal.

According to a second aspect of the invention, in the invention of the first aspect, the difference between the output value of the pulse / rotation speed converter and the set number of circuits is monitored, and this difference is the speed regulation stability determination value or the speed regulation stability determination value. And a pulse speed / rotation speed converter while switching the input value of the pulsation cycle calculation portion to the set rotation speed in response to the speed control stability determination portion which generates a switching command signal when the deviation is out of the range. The output value of 1 is used as the engine speed signal which is compared and calculated with the set speed signal.

[0020]

According to the invention of claim 1, the average rotation speed calculation unit calculates an average rotation speed in the pulsation cycle which is not affected by the miss pulse, and the average rotation speed is set as the actual rotation speed, and the average rotation speed and the set rotation speed are set. The engine speed is controlled so that there is no deviation from the number.

According to the second aspect of the present invention, when the difference between the output value of the pulse / rotation speed converter and the set rotation speed deviates from the preset speed regulation stability determination value or the speed regulation stability determination range (the engine speed is increased). During deceleration, etc.), the output value of the pulse / rotation speed converter is used as the actual rotation speed, and the engine speed is controlled so that there is no deviation between the output value and the set rotation speed. When in the speed stability determination range, the operation of claim 1 is executed.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes an engine speed detector, which is arranged in proximity to a turning gear (not shown) of a diesel engine, and in this embodiment, each time the tooth portion or the valley portion of the turning gear is detected. A pulse generator is used to generate a pulse. Reference numeral 2 denotes a pulse / rotation speed converter, which takes in a pulse signal P output from the pulse generator 1 and calculates an engine speed N based on the pulse signal P.

A mode selector 3 includes an AND circuit (gate circuit) 4 and a switch (SW) 5. The AND circuit (gate circuit) 4 includes a timer 1 described later.
When the mode switching signal from 2 is at "L" level,
The pulse signal P is passed to the integrated number counter 7 of the average rotation number calculation unit 6 described later.

The switch (SW) 5 is closed (ON) every time the output level of the AND circuit 4 becomes "H", and the engine speed output from the pulse / speed converter 2 is changed to the average speed. Input to the integrator 8 of the calculation unit 6. The integrator 8 integrates this engine speed.

The average rotation speed calculation unit 6 includes the above-described integral number counter 7 and integrator 8, and a divider 9.
The integral number counter 7 counts +1 every time the output level of the AND circuit 3 becomes “H”. The count value of the integrated number counter 7 is the number of times of input data of the integrator 8. The divider 9 receives this signal as a division command when the mode switching signal from the timer 12 described later is at the “H” level, takes in the count value of the integral number counter 7 and the integral value of the integrator 8, and The integrated value is divided by the counter value of the integrated number counter 7. This divided value becomes the average rotation speed Ni-i-1 of one pulsating section during one rotation of the engine. Then, at the end of the division, a zero clear signal is output to the counter 7 and the integrator 8, and the division result is held until the next mode switching signal becomes the "H" level.

Reference numeral 10 is a pulsation cycle calculator / setting unit, which comprises a pulsation cycle calculator 11 and the timer 12 described above. The pulsation cycle calculator 10 calculates (predicts) the next pulsation cycle T (time) (average pulsation cycle) from the average rotation speed Ni-i-1 and the number of cylinders Z of the engine, and the pulsation cycle T = 60 / average Rotational speed Ni-i-1 / Z (1) This pulsation time T is set in the timer 12.

When the pulsation time T is set in the timer 12,
When the measurement of the pulsation time T is started and the time measurement is completed, a time-up signal (H level) of a minute time width is output. An L level signal is output during timing. This H level / L level signal output from the timer 12 is the mode switching signal, and when it is at the L level as shown in FIG. 2, the average rotation speed calculation unit 6 is in the counting / integrating mode and at the H level. At times, the average rotation speed calculation unit 6 is in a mode for calculating the average rotation speed. Further, during this H level, the calculation of the pulsation frequency calculation T and the setting of the T to the timer 12 are executed.

That is, when the output of the timer 12 is at the L level, the data fetching mode for fetching the integrated data and the integrated number data is set, and when the output of the timer 12 is at the H level, the arithmetic operation for calculating the average rotational speed and the pulsation time T is performed. Enter the processing mode.

Reference numeral 13 denotes an engine speed setting device which outputs an engine speed setting signal Ns, and a deviation amplifier 14 causes a deviation between the value Ns of the engine speed setting signal and the average speed Ni-i-1. Calculate ΔN. The control calculator (PID controller) 15
Based on this deviation ΔN, the fuel injection amount to be injected into the diesel engine 102 is obtained, a fuel injection amount signal is output to the fuel pump, and a rack (not shown) of the fuel pump is operated.

(A) In this embodiment, the integrated number count 7
Then, the number of pulses output from the pulse generator 1 is counted,
Since this value divides the integral value of the engine speed sent by the pulse / speed converter 2, the average speed sent by the divider 9 is hardly affected by the miss pulse.

(B) Further, this average rotation speed always corresponds to the actual rotation speed of the engine, and the set rotation speed N set by the operation of the ship operator coincides with the average rotation speed. However, the above-mentioned feeling of incongruity does not occur, and it becomes easy to operate.

When the operation of the above-mentioned embodiment is executed by using a computer such as a microcomputer, when a pulse arrives from the rotation speed detector 1, as shown in FIG.
It is determined which one of the above-mentioned data acquisition mode / arithmetic processing mode is selected (step 1). In the data acquisition mode, set the integral number counter to +
Then, the engine speed output from the pulse / rotation speed converter 2 is read through the A / D converter (step 2) and the engine speed is integrated. This flow
It is executed each time a pulse arrives from the rotation speed detector 1.

When the pulsation time T elapses and the arithmetic processing mode is entered, a flag to that effect is set and the calculation routine (step 2 to step 9) shown in FIG. 4 is executed.

FIG. 5 shows a second embodiment of the present invention.

In the figure, reference numeral 16 denotes a speed regulation stability determination unit, which is an absolute value circuit 17 and a speed regulation stability determination value setter 18.
And a comparator 19. In the absolute value circuit 17,
The deviation between the engine speed set value Ns output by the subtractor and the output value of the pulse / rotation speed converter 2 is input. The comparator 19 compares the absolute value of the deviation with the speed regulation stability determination value (or the speed regulation stability determination value area), and when the absolute value of the deviation deviates from the speed regulation stability determination value (or the speed regulation stability determination value area), A switching command signal (“H” level) is generated. A switching unit 20 receives the switching command signal (“H” level) from the speed regulation stability determining unit 16 to disconnect the pulsation cycle calculator 11 and the divider 9 from each other and cause the pulsation cycle calculator 11 to rotate the engine. At the same time as the switch 20A for connecting the number setting device 13, the subtractor 14 and the divider 9 are disconnected, and the
The switch 20B for connecting the rotation speed converter 2 is provided.

Here, the speed regulation stability determination value (or the speed regulation stability determination value range) is a value called a settling speed, and stable speed control is performed when the set speed is constant. Engine speed N and set speed N that can be determined
If the absolute value of this deviation is within 2 RPM of the set rotational speed Ns, it is considered that stable speed control is being performed.

A filter 21 is connected between the pulse / rotation speed converter 2 and the absolute value circuit 17. The filter 21 removes the output value of the pulse / rotation speed converter 2 that has exceeded the fluctuation range of the actual rotation speed due to the fluctuation of the load. That is, in the filter 21, the rotation speed output from the engine rotation speed detector 1 largely fluctuates due to actuator and load fluctuations, and pulsation is added to this.
It serves to cut ± 3 to 4 (RPM) when there is a distance of ± 3 to 4 (RPM) from the speed regulation stability determination value setting device 18.

In this embodiment, after the deviation between the engine speed set value Ns and the output value of the pulse / rotation speed converter 2 reaches the settling speed, the pulsation cycle calculator 11 determines that the pulsation cycle T = 60. ÷ Engine rotation speed set value N ÷ Z ······················· (2) is calculated and the output value N of the pulse / rotation speed converter 2 is treated as an actual rotation speed.

In the embodiment of FIG. 5, the engine speed setting value Ns
When the difference between the output value of the pulse / rotation speed converter 2 is out of the speed regulation stability determination value (or the speed regulation stability determination value range) (for example, during acceleration / deceleration of the engine), the input of the PID controller 15 is Since there is a deviation between the engine speed N and the set speed Ns,
Compared to the case where the input is the deviation between the average rotation speed and the set rotation speed Ns, the control followability is excellent. For example, at the time of acceleration, the engine speed N increases as the set speed Ns increases.
As shown in, the difference Δ between the average rotation speed Ni-i-1 and the engine rotation speed N becomes large. Therefore, in this embodiment, the average rotation speed Ni-
The engine speed N is used instead of i-1.

When the difference between the engine speed set value Ns and the output value of the pulse / rotation speed converter 2 reaches the speed regulation stability determination value (or the speed regulation stability determination value range) and the speed regulation is stabilized, the operation shown in FIG. The same operation is performed as the example operation.

[0042]

As described above, the present invention averages the pulsating engine speed per pulsation cycle without the influence of the miss pulse, and sets the average speed as the actual engine speed. Since the engine speed is controlled, the control accuracy and reliability of the engine speed control can be improved as compared with the conventional one.

Further, since the above-mentioned average number of revolutions substantially always corresponds to the set number of revolutions and there is no change due to the sample timing as in the case of the conventional sample and hold, the operating performance of the device is higher than that of the conventional technique. Is improved.

Further, according to the second aspect of the present invention, when the engine is accelerated or decelerated, the control is performed based on the deviation between the engine speed detected by the detector and the set speed instead of the average speed. It is also possible to perform speed control such as during acceleration / deceleration without delay.

[Brief description of drawings]

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

FIG. 2 is a time chart for explaining the operation of the above embodiment.

FIG. 3 is a flowchart when the operation of the above embodiment is executed by a CPU.

FIG. 4 is a flowchart when the operation of the above-described embodiment is executed by a CPU.

FIG. 5 is a block diagram showing a second embodiment of the present invention.

FIG. 6 is a diagram for facilitating understanding of the operation and effect of the second embodiment.

FIG. 7 is a block diagram showing a conventional speed governor of a diesel engine.

FIG. 8 is a waveform time chart for explaining problems of the conventional speed governor of a diesel engine.

[Explanation of symbols]

 1 engine speed detector 2 pulse / speed converter 3 mode switcher 4 AND circuit (gate circuit) 5 switch 6 average speed calculator 7 integral number counter 8 integrator 9 divider 10 pulsation cycle calculator / setting unit 11 Pulsation cycle calculator 12 Timer 13 Engine speed setting device 15 PID controller 16 Speed regulation stability determination unit 17 Absolute value circuit 18 Speed regulation stability determination value setter 19 Comparator 20 Switching unit 20A, 20B switch

Claims (2)

[Claims] Claim: What is claimed is: 1. An engine speed, in which the engine speed periodically pulsates, is calculated by comparison with a set speed, and the fuel pump rack position of the engine is adjusted based on the result of the comparison and supplied to the engine. (A) a pulse generator that is disposed in the vicinity of a turning gear that rotates with the rotation of the engine and that generates a pulse according to the rotation of the turning gear, A pulse / rotation speed converter that takes in the output of the pulse generator to calculate the engine speed, and (C) the pulsation cycle calculated by the pulsation cycle calculation unit, integrates the engine speed, and the integrated value And (D) the pulsation cycle calculation unit has an average rotation speed calculation unit that calculates an average rotation speed from the number of integrations, and the next pulsation based on the average rotation speed or the set rotation speed and the number of cylinders of the engine. Play cycle And (E) the average rotation speed is used as an engine rotation speed signal which is compared and calculated with the set rotation speed signal. 2. A controller that monitors a difference in output value of the pulse / rotation speed converter with respect to the set number of circuits, and generates a switching command signal when the difference is a speed regulation stability determination value or deviates from the speed regulation stability determination value. In response to the speed stability determination unit and the switching command signal,
It is characterized in that it has a switching unit for switching the input value of the pulsation cycle calculation unit to the set rotation speed and for making the output value of the pulse / rotation speed converter the engine rotation speed signal which is compared and calculated with the set rotation speed signal. The engine speed control device according to claim 1.