JPS592777B2 - Electronic governor for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an electronic speed governor for an internal combustion engine whose actuator can be made small and lightweight.

Prior Art Conventionally, in an electronic speed governor for an internal combustion engine, an actuator, which is an electro-mechanical converter for controlling the position of a control rack, which is a fuel adjustment member, has been disclosed, for example, in Japanese Patent Publication No. 51-7376. A moving coil type using a permanent magnet as proposed, or a
An electromagnetic plunger type as proposed in Publication No. 3035 is generally used.

However, the former is expensive because it requires the use of a magnet with a large holding force, and the movable part has a moving coil, so the mass of the movable part is heavy, so it is especially difficult to install it in a vehicle. In some cases, there is a problem in that the control operation is likely to be adversely affected by the inertial force of the movable part due to external force.

On the other hand, the latter has the characteristic that the force acting on the plunger in the electromagnetic solenoid weakens in inverse proportion to the square of the distance from the reference point even if the excitation current is constant. In order to use it as an actuator,
It is necessary to use the plunger in such a way that the force acting on the plunger changes little with respect to the positional displacement of the plunger.

For this reason, it is necessary to operate the plunger at a certain distance from the reference point, and therefore, in order to obtain the specified force, the overall shape must be increased, making miniaturization difficult. Ta.

OBJECTS OF THE INVENTION An object of the present invention is to provide an inexpensive, high-performance internal combustion engine that reduces the weight of the moving parts of the actuator of an electronic speed governor, thereby reducing the influence of disturbance forces on control operations. The purpose of the present invention is to provide an electronic speed governor for use.

Structure of the Invention The present invention includes an electromagnetic plunger type actuator for positionally displacing a fuel adjustment member that adjusts the amount of fuel supplied to an internal combustion engine, and a mark and a space corresponding to the rotational speed and accelerator opening of the internal combustion engine. a pulse generating means for outputting a pulse signal whose ratio changes; and a pulse generating means for outputting a pulse signal having a varying ratio; An electronic speed governor for an internal combustion engine is provided, which includes a peak value limiting means for limiting the voltage applied to the control coil of the actuator to a magnitude corresponding to the position.

Example Hereinafter, the present invention will be described in detail with reference to illustrated embodiments.

FIG. 1 shows a block diagram of an embodiment of a speed governor according to the present invention.

The speed governor 1 has an actuator 2 of an electromagnetic plunger type for positionally displacing a fuel control rod of a fuel injection pump according to the rotational speed of the diesel engine and the opening degree of the accelerator.

An electromagnetic plunger type actuator is an actuator consisting of an electromagnet and a magnetic body movably disposed within the unequal magnetic field created by the electromagnet.

As shown in FIG. 2, this actuator 2 includes a casing 3 made of a magnetic material fixed to a housing 30 of a fuel injection pump, and inside the casing 3 are magnetic poles 4 and 5 formed into a substantially cylindrical shape. An electromagnet is formed by the control coil 6.

Each of the magnetic poles 4 and 5 has a connecting rod 7 made of a non-magnetic material and a plunger 8 made of a magnetic material such as iron or nickel and fitted so that its axis coincides with one end of the connecting rod T, respectively, in the through hole 4a. and 5a.

A magnetic path is formed by the casing 3 between the magnetic pole 4 and the magnetic pole 5, and when the control coil 6 is energized, the magnetic path 4, 5
A magnetic field is created in a closed space surrounded by the control coil 6 and the plunger 8, and the plunger 8 is attracted in the direction of arrow A.

Therefore, the gap between the inner circumferential surface of the through hole 5a and the outer circumferential surface of the plunger 8 is made as narrow as possible within the limit that does not hinder the movement of the plunger 8 in the axial direction, and the magnetic resistance between the magnetic pole 5 and the plunger 8 is reduced. It is desirable to make it small.

The other end of the connecting rod 7 is connected to a fuel adjustment rod (
It is fitted and fixed to one end of the control rack (control rack) 9 so that its axes coincide with each other.

The fuel adjustment rod 9 has a spring holding plate 10 fixed to one end thereof.
The fuel adjustment rod 9 is biased in the direction of arrow B by a resilient spring 11 provided between the fuel adjustment rod 9 and the casing 3 on the outer periphery of the fuel adjustment rod 9.

The actuator 2 further includes a magnetic core 1 which is fixed to the spring holding plate 10 and is displaced in accordance with the positional displacement of the fuel adjustment rod 9.
2, and a position detection coil 13 in which the magnetic core 12 moves forward and backward so that the inductance changes in accordance with the displacement of the magnetic core 12.

Returning to FIG. 1, the governor 1 has a pulse generating circuit 14 that outputs a pulse signal S1 whose mark-space ratio changes in accordance with the rotational speed of the internal combustion engine and the degree of accelerator opening.

The pulse generating circuit 14 includes an accelerator signal generator 15 that generates an accelerator signal S2, which is a DC voltage of a magnitude corresponding to the accelerator opening degree, and a rotation speed signal S3, which is a DC signal of a magnitude corresponding to the rotational speed of the engine. A rotational speed signal generator 16 for generating the rotational speed signal is provided.

The rotational speed signal generator 16 includes a rotational signal generator 17 that is connected to the rotational shaft of the engine and generates a pulse signal having a frequency corresponding to the rotational speed of the engine, and a differential detection circuit 18 that differentiates and detects this pulse signal. It consists of a monostable multivibrator 19 triggered by a fractional signal from a differential detection circuit 18, and an integrator 20 that integrates the output from the monostable multivibrator 19.

As can be easily understood from the above circuit configuration, the monostable multivibrator 19 generates a pulse signal such that the mark-space ratio is small when the rotation speed is low, and the mark-space ratio is high when the rotation speed is high. .

Therefore, by integrating this pulse signal with the integrator 20, a DC signal having a magnitude corresponding to the rotational speed of the engine can be generated.

Note that the mark-space ratio here is the ratio of the low level period TL to the high level period TH in one cycle of the continuous pulse signal, and is defined as TH/TL.

The accelerator signal S2° and the rotational speed signal S3 are input to the arithmetic circuit 21, and as shown in FIG. 3, the accelerator opening degree θ1. A slice level signal S4 having characteristics such that the magnitude of the DC output voltage V with respect to the rotational speed N of the engine is varied by θ2θ3, . . . is generated.

The level of this signal S4 increases as the rotational speed N increases and as the accelerator opening degree θ decreases (θ1, θ2, θ3, etc.).

The pulse generating circuit 14 further includes an oscillator that outputs a waveform having a slope whose output level changes with time at a constant period and a constant magnitude, and in the illustrated embodiment, a sawtooth wave signal. This is a sawtooth wave generator 23 that generates S5.

The sawtooth wave signal S5 and the slice level signal S4 are input to the comparator 22, and a mark corresponding to the signal width of the sawtooth wave signal S5 at the level of the slice level signal S4 is generated.
A pulse signal S1 having a spacing ratio is created.

In the illustrated example, as shown in FIG. 4, the pulse signal S has the same pulse width as the sawtooth signal S at the level of the slice level signal S4, and They have the same period.

Therefore, when the slice level signal S4 changes as shown in FIG.

A pulse signal S1 is obtained which rises and falls at a point where the levels coincide with each other.

In the illustrated case, when the level of the slice level signal S4 decreases, the mark-space ratio of the pulse signal S11 becomes thicker, and when the level of the signal S4 increases, the mark-space ratio of the pulse signal S11 increases.
The mark-space ratio is now smaller.

The pulse signal S1 is controlled by the actuator by limiting the peak value of the pulse signal S1 to a magnitude corresponding to the position of the fuel control rod 9 so that the electromagnetic tensile force of the actuator 2 is approximately constant regardless of the position of the fuel control rod. The signal is input to a peak value limiting circuit 24 which applies the voltage to the control coil 6 of No. 2.

The peak value limiting circuit 24 controls the position detection coil 13 and the fuel adjustment rod 9 by changing the inductance of the position detection coil 13.
The position signal S6 is a DC voltage of a magnitude corresponding to the position of
a position signal generator 25 that outputs a pulse signal S1;
and a peak value limiter 26 which receives the position signal S6 and limits the peak value of the pulse signal S1 according to the level of the position signal S6 and outputs a control pulse signal S7.

The position signal generator 25 has an oscillator using the position detection coil 13 as an oscillation coil.
The oscillation frequency is changed in accordance with the change in the inductance of the fuel control rod 9 according to the positional displacement of the fuel adjustment rod 9, and the position signal S6 is generated based on the change in frequency.

The level of the position signal S6 becomes smaller as the fuel adjustment rod 9 is displaced in the direction of arrow A.

In the peak value limiter 26, as shown in FIGS. 5a and 5b, the pulse signal S inputted with a constant peak value is limited in its peak value in accordance with the leveling of the position signal S6, It is output as a control signal S7.

The control signal S7 is input to the power amplification circuit 2γ, where the power is amplified to a level sufficient to operate the actuator 2, and the amplified power is applied to the control coil 6.

Next, the operation of the speed governor 1 will be explained.

When the diesel engine is operated in a steady state under a constant load, the accelerator signal S2 and the rotational speed signal S3 are each constant values, and the mark-space ratio of the pulse signal S1 is a constant value. Retained.

This pulse signal S1 is applied to the control coil 6 with its peak value being limited in accordance with the position of the fuel adjustment rod 9 without changing its mark-space ratio.

The control coil 6 is energized in the direction of arrow A (Fig. 2) by the pulse signal S1, and the greater the mark-space ratio, the more the fuel adjustment rod 9 moves to the left in Fig. 2, and the amount of fuel supplied increases. The governor 1 is in an equilibrium state at the point where the actuator 2 positions the fuel adjustment rod 9 at a position that supplies an amount of fuel corresponding to the magnitude of the load.

When the load increases for some reason, the rotational speed of the engine decreases, and therefore, as can be seen from FIGS. 3 and 4, the level of the slice level signal S4 decreases and the mark-space ratio of the pulse signal S6 increases. .

Therefore, the plunger 8 of the actuator 2 moves in the direction of arrow A in FIG. 2 to increase the amount of fuel supplied, but at this time, the magnetic core 12 enters the position detection coil 13 and increases its inductance, thereby producing a position signal. S6 level f
Make it smaller (see Figure 2).

The force F acting on the plunger 8 of the actuator 2 changes as shown in FIG. 6 depending on the distance X between the magnetic pole 4 and the plunger 8 (see FIG. 2) and the magnitude of the current i flowing through the control coil 6.

The peak value limiting circuit 24 sets the value of X to X1'#X so that the electromagnetic tensile force of the actuator 2 is approximately constant regardless of the value of X, that is, regardless of the position of the fuel adjustment rod.
2, x3, and X4, the peak values of the pulse signal S□ are 11, j2yi3, and j2yi3, respectively. It is set so that i changes continuously in response to continuous changes in X, as shown by a curve such as i4 (shown by the dotted line in FIG. 6).

Therefore, the tensile force F remains approximately constant regardless of the position of the plunger 8.

Therefore, when the plunger 8 moves in the direction of the arrow A as the mark space ratio of the control signal S7 increases, the force F acting on the plunger 8 can be kept approximately constant, and the plunger 8
moves to a point where the elastic force of the spring 11 and the attractive force are balanced so that the engine reaches a predetermined rotational speed.

Since the control signal S7 is a pulse, the fuel adjustment rod 9 vibrates slightly at this position, but by setting the period of the control signal S7 relatively high compared to the engine rotation speed, the engine Stable operation is possible regardless of vibration.

On the other hand, if the engine speed increases due to reasons such as a lightening of the engine load, the fuel adjustment rod 9 moves in the direction of arrow B by operating in the opposite manner to the above explanation, and the engine speed increases. It is held at a predetermined value.

In this way, the peak value limiting circuit 24 controls the pulse signal S
Since the peak value of 1 can be limited by the position of the plunger 8 and the suction force F can be made approximately constant regardless of the position of the plunger 8, the characteristic diagram of FIG. A sloped portion of the characteristic shown by the solid line can be used, thus improving the electro-mechanical conversion efficiency of the actuator.

Therefore, as long as the required suction force remains the same, the actuator can be made significantly smaller and lighter than conventional actuators.

In the above embodiment, the sawtooth wave generator 23 is used as the oscillator of the pulse generator 14, but a triangular wave generator may also be used.

Effects of the Invention According to the present invention, as described above, the output of the mechanical force of the actuator can be made constant regardless of the position of the plunger, making it easier to control the fuel adjustment member and improving the efficiency of the actuator. Therefore, the actuator can be made smaller and lighter, and the movable parts of the actuator can also be made smaller and lighter, so when a disturbance force moves on the actuator, the force applied to the actuator's movable parts can be suppressed to a small level, resulting in a good performance. This has the effect of providing controllability.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a sectional view of an actuator of an embodiment of the invention, Fig. 3 is a characteristic diagram of slice level signal S4, and Fig. 4 a and b are comparators. FIGS. 5a and 5b are waveform diagrams for explaining the operation of the peak value limiter, and FIG. 6 is a characteristic curve diagram for explaining the operation of the embodiment shown in FIG. DESCRIPTION OF SYMBOLS 1... Speed governor, 2... Actuator, 6... Control coil, 8... Plunger, 9... Fuel adjustment rod,
12... Magnetic core, 13... Position detection coil, 14
... Pulse generation circuit, 15 ... Accelerator signal generator, 16 ... Rotation speed signal generator, 21 ... Arithmetic circuit, 23 ... Sawtooth wave generator, 22 ... Comparator, 24
... Peak value limiting circuit, 25 ... Position signal generator, 26
... Peak value limiter, Sl... Pulse signal, S2...
・Accelerator signal, S3... Rotation speed signal, S4...
Slice level signal, S5... sawtooth wave signal, S6.
...Position signal, S7...Control signal.

Claims (1)

[Claims] 1. An electromagnetic plunger type actuator for positionally displacing a fuel adjustment member that adjusts the amount of fuel supplied to an internal combustion engine;
pulse generating means for outputting a pulse signal whose mark-space ratio changes in accordance with the rotational speed of the internal combustion engine and the degree of accelerator opening; An internal combustion engine characterized by comprising: a pulse height limiting means for limiting the pulse height of the pulse signal to a magnitude corresponding to the position of the fuel adjustment member so that the pulse signal remains substantially constant, and applying the pulse to the control coil of the actuator. Electronic speed governor for engines. 2. An accelerator signal generating means in which the pulse generating means generates an accelerator signal corresponding to an accelerator opening degree, a rotational speed signal generating means to generate a rotational speed signal having a magnitude corresponding to the rotational speed of the internal combustion engine, and the accelerator. control signal calculation means for calculating a control signal for positioning the fuel adjustment member at an optimal position based on the signal and the rotational speed signal; and means for generating a pulse signal having a mark-space ratio corresponding to the control signal. An electronic speed governor for an internal combustion engine according to claim 1, characterized by comprising: