JPS614847A - Controller for system equipped with prime mover and hydraulic pump - Google Patents

Abstract

PURPOSE:To improve fuel consumption and operation performance by using a prime mover in a low-revolution and low output range when the load applied into a hydraulic pump is small, and by increasing the number of revolutions as the load increases, and then by using the prime mover in a high revolutions and high output range. CONSTITUTION:If the load of a hydraulic pump 3 is small, when the instructed revolution-speed signal Nso for a relatively low revolution speed is instructed by a fuel throttle lever 5, the output revolution-speed signal N of a prima mover 1 and the instructed revolution-speed signal Nso are early equal. Therefore, Nso is set as an aimed revolution-speed signal No, and the fuel injection amount of a fuel injection pump 2 and the discharge amount of the hydraulic pump 3 are controlled. When the load of the hydraulic pump 3 increases in this state and the output revolution-speed signal N reduces, the revolution-speed deviation DELTAN increases, and when DELTAN exceeds a set value (a),an increased revolution-speed signal Nn is generated from an increased revolution-speed generator 12. Then, the signal Nn is added 13 into the signal Nso, and the aimed revolution-speed signal No is corrected.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention controls the fuel injection amount of a prime mover and the discharge amount of a hydraulic pump based on a rotation speed deviation signal between a target rotation speed signal of the prime mover and an output rotation speed signal. The present invention relates to a control device for a system including a prime mover and a hydraulic pump.

[Background of the invention]

FIG. 6 is a block diagram showing a conventional control device for a system including a prime mover and a hydraulic pump as disclosed in detail in Japanese Patent Application Laid-Open No. 57-65822.

In the figure, 1 indicates a prime mover such as a diesel engine, and 2 is a so-called electronic fuel injection pump that electrically controls the amount of fuel injected into the prime mover. 3 is a variable displacement hydraulic pump driven by the prime mover Ja1, and 4 is a so-called electronic pump regulator that controls the tilt angle of the swash plate (or oblique shaft) of the hydraulic pump 3 by an electric signal. prime mover l
command rotation speed signal N5o (in this case, target rotation speed signal N
.

) is set by the driver using the fuel throttle lever 5, the output rotation speed signal N of the power source motor 1 is detected and output by the rotation detector 6, and the adder 7 outputs the target rotation speed signal No and the output rotation speed. A rotational speed deviation signal ΔN with respect to the number N is calculated and output. Displacement of a rack (not shown) of the fuel injection pump 2 is detected by a rack position detector (not shown), and a rack position signal is output. The adder 8 controls the rack position based on the deviation signal Lo between the rotation speed deviation signal ΔN given as the rack target position signal and the rack position signal,
The fuel injection amount of the fuel injection pump 2 is determined.

Further, 9 is a pump control function generator, which generates a pressure signal P from a pressure detection illumination provided in the discharge pipe 10 of the hydraulic pump 3.
and the rotational speed deviation signal ΔN from the adder 7, and output a pump tilting amount signal Xq for controlling the discharge amount to the regulator 4 of the hydraulic pump 3.

The rotational speed deviation signal ΔN increases as the load on the hydraulic pump 3 increases and the output rotational speed N decreases, and conversely decreases as the load on the hydraulic pump 3 decreases and the output rotational speed N increases. . Therefore, as ΔN increases, the electronic fuel injection pump 2 moves the rack position in the direction of increasing the fuel injection amount to increase the output of the prime mover 1, suppressing the decrease in the output rotation speed N, and increasing ΔN. When it becomes smaller, the fuel injection amount is reduced to prevent the output rotational speed N of the prime mover 1 from becoming excessive.

The input torque of the hydraulic pump 3 is proportional to the product of the swash plate tilting amount and the discharge pressure. Therefore, the load on the hydraulic pump 3 increases (the discharge pressure P increases), and the output rotation speed signal N of the prime mover 1 increases.
decreases and the one-rotation speed side difference signal ΔN increases, the pump control function generator 9 decreases the product of the pump tilting amount signal Xq and the discharge pressure signal P as ΔN increases, and the hydraulic pump 3
The displacement amount signal Xq is outputted so that the input torque of the engine 1 decreases along the output torque line of the engine 1 set by the slot lever 5 of the engine 1, and the discharge amount of the hydraulic pump 3 is decreased.

In the control system of a conventional system including a prime mover and a hydraulic pump configured as described above, the output of the prime mover 1 is determined by the target rotational speed signal No. (=
The disadvantage is that it is regulated by the Nso. That is, when the maximum target rotation speed of the prime mover 1 is commanded by the throttle lever 5, the prime mover 1 is driven at the maximum rotation speed even when the load on the hydraulic pump 3 is small, resulting in a worsening of the fuel consumption rate. If a relatively low target rotation speed is commanded with the throttle lever 5, when the load on the hydraulic pump 3 becomes large, the output of the prime mover cannot be increased to the maximum output at the high target rotation speed, and the load becomes large. cannot be driven. Therefore, the driver must constantly operate the fuel throttle lever 5 according to the load on the hydraulic pump 3 in order to deal with the above problem, and this operation is not only very troublesome but also requires skill. It has been difficult for humans to completely follow changes in load using their sense of operation.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned drawbacks of the conventional control device, and when the load applied to the hydraulic pump is small, the prime mover is used in a region with relatively low rotation and relatively low output, and when the load becomes large, the motor is automatically activated. Increase the rotation speed, use the yX motive in a region where the rotation speed is high and the output is large, and #! ! The purpose is to improve the cost consumption rate and operability.

[Summary of the invention]

To achieve this object, the present invention uses an increased rotation signal set in response to an increase or decrease in a rotation speed deviation signal, which is the difference between a target rotation speed signal and an output rotation speed signal, as a command rotation speed signal of a fuel throttle lever. By adding up the target rotation speed signal and controlling the fuel injection amount and hydraulic pump discharge amount based on this target rotation speed signal, when the load on the hydraulic pump is light, the relatively low target commanded by the throttle lever can be achieved. The output rotation speed of the prime mover is controlled based on the rotation speed signal, and when the load on the hydraulic pump increases, the output rotation speed of the prime mover is controlled based on the high target rotation speed compensation that increases in response to the increase in the rotation speed deviation signal. It is something to control.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 shows a control block diagram of a system including a prime mover and a hydraulic pump according to an embodiment of the present invention, and the same parts as in FIG. 6 are given the same reference numerals.

Reference numeral 12 denotes an increased rotational speed function generator which inputs the rotational speed deviation signal ΔN from the adder 7 and generates an increased rotational speed signal Nn. 1
3 is an adder provided between the fuel throttle lever 5 and the adder 7, which adds an increased rotational speed signal Nn to the command rotational speed signal Nso of the fuel throttle lever 5 to obtain a target rotational speed signal NO; This No. is output to the adder 7.

Examples of the functional relationship of ΔN-Nn of the increased rotational speed function generator 12 are shown in FIGS. 2 and 3.

In Figure 2, the vertical axis shows the increased rotational speed signal Nn, and the horizontal axis shows the rotational speed deviation signal ΔN.If ΔN exceeds the set value a, Nn
increases in a stepwise manner from O to Nnmax.

In Figure 3, the vertical axis and horizontal axis are the same as in Figure 2. When ΔN exceeds point a, Nn increases in proportion to the size of ΔN, and at point b, N n = N n m a x. It is what it is.

The effect will be explained. When the fuel throttle lever 5 commands a relatively low rotational speed command signal N-so, when the load on the hydraulic pump 3 is small, the output rotational speed signal N of the prime mover 1 and the command rotational speed signal Nso become close to each other. Therefore, NsO is the target rotation speed signal NO.
As a result, the fuel injection amount of the fuel injection pump 2 and the discharge amount of the hydraulic pump 3 are controlled.

From this state, when the load on the hydraulic pump 3 increases and the output rotational speed signal N of the prime mover 1 decreases, the rotational speed deviation signal Δ
When N increases and ΔN exceeds the set value a, an increased rotational speed signal Nn is generated from the increased rotational speed generator 12, and the adder 1
In step 3, Nn is added to the command rotation speed signal Nso to become the target rotation speed signal NO. Therefore, the fuel injection amount of the fuel injection pump 2 and the discharge amount of the hydraulic pump are controlled by a high target rotation speed signal NO obtained by adding Nn to the command rotation speed signal Nso commanded by the throttle lever 5.

According to the above embodiment, the following effects are achieved.

(1) When the load on the hydraulic pump 3 is small, the prime mover l
The engine can be used at low rotational speeds and low output to improve fuel consumption and reduce the noise generated by the prime mover.

(2) When the load on the hydraulic pump 3 increases, the target rotational speed of the prime mover 1 automatically increases, and the prime mover 1 can be operated in a region with a high rotational speed and a large output.

(3) Since the target rotation speed of the prime mover 1 can be automatically made to follow a change in the load on the hydraulic bonzo 3, the driver's operation becomes less cumbersome and the operability is improved.

4 and 5 show an example in which the ΔN-Nn function of the increased rotational speed generator 12 shown in FIG. 1 is provided with hysteresis. In each figure, the same parts as in FIGS. 2 and 3 are given the same reference numerals.

Figure 4 shows that when the load on the hydraulic pump 3 gradually increases and the rotation speed deviation signal ΔN exceeds the set value &1, Nn = N n m
When the load decreases from this state and ΔN becomes smaller, ΔN becomes the set value a
2 < a x ), Nn=0 (this path is indicated by an arrow).

In the examples shown in Figures 2 and 3, Nn is a uniquely determined value for ΔN, so a slight change in ΔN will cause the value of Nn to increase or decrease frequently, causing discomfort to the driver. However, if the control is performed using a function with hysteresis as described above, there will be no change in the target rotational speed No within the range of a 2 <N n < a 1 , thereby eliminating the driver's discomfort.

Figure 5 shows another example where the function has hysteresis. When ΔN increases and exceeds al, Nn increases in proportion to ΔN, and when ΔN is b, Nn = N n rn
ax, and becomes a constant value for ΔN beyond that. As ΔN decreases from this state, ΔN becomes bz (bz
<bz), hold Nn=NnmaX until + bz<Δ
When N < a z, it decreases with the value of Nn proportional to ΔN,
When ΔN < az, Nn=0. Also, Nn increases in proportion to ΔN, and C
Conversely, if ΔN decreases from N n = N n c at point z, then N n = N between C2 and ΔN <'C1.
n e is held, and when a=(ΔN<C2), the value of Nn of a preset setting line (a2bz) is output.

If the function has hysteresis as described above, it is possible to continuously set the target rotation speed of the prime mover 1 according to the magnitude of the load, and also to adjust the load of the hydraulic pump 3 as in the example shown in FIG. Frequent increases and decreases in the rotational speed of the prime mover 1 due to fluctuations can be suppressed, and driver discomfort can be avoided.

〔Effect of the invention〕

According to the present invention described above, in a control device for a system including a prime mover and a hydraulic pump, when the load on the hydraulic pump is small, the prime mover is controlled in a low output range, and when the load on the hydraulic pump is large, the prime mover is controlled in a high output range. Since the rotational speed of the prime mover can be automatically controlled in the range, the fuel consumption rate can be improved and the operability during operation can be improved.

[Brief explanation of the drawing]

Fig. 1 is a control block diagram of a system including a prime mover and a hydraulic pump according to the present invention, Fig. 2 is a diagram showing an example in which the function set in the increased rotation speed function generator of Fig. 1 is made into a step shape, and Fig. 3 The figure shows an example in which the function set in the increasing rotation speed function generator is set in a proportional relationship. Figure 4 is a diagram showing an example in which the function set in the increasing rotation speed function generator is set in a step shape and with hysteresis. , Figure S is a diagram showing an example in which the function set for the increased rotational speed generator is in a proportional relationship and has hysteresis.
The figure is a control block diagram of a conventional system including a prime mover and a hydraulic pump. ■... Prime mover, 2... Fuel injection pump, 3... Hydraulic pump, 4... Regulator, 5... Fuel throttle lever, 6...
...Rotation detector, 7.8°13...Adder,
11... Pump control function generator, 12...
...Increase rotation speed function generator, N...Output rotation speed signal, No.....Target rotation speed signal, Nn...
Increased rotation speed signal, Nso... command rotation speed signal,
ΔN・・・Rotation speed deviation number. Kabuto 2 Ward Kabuto 3 Diagram Rotation Number

Claims (3)

[Claims] (1) Obtain a rotational speed bias signal that includes a prime mover and a hydraulic pump driven by the prime mover and is the difference between the target rotational speed signal and the output rotational speed signal of the prime mover, and use this rotational speed bias signal as In the system that controls the fuel injection amount of the prime mover and the discharge amount of the hydraulic pump based on the engine speed, an increased rotation speed signal set in response to an increase or decrease in the rotation speed deviation signal is added to the command rotation speed signal of the fuel throttle lever. A control device for a system including a prime mover and a hydraulic pump, characterized in that the target rotation speed signal is set as a target rotation speed signal. (2) The increasing rotational speed signal increases from the first setting value of the rotational speed deviation and decreases to the second setting value of the rotational speed deviation, and the first setting value has a greater hysteresis than the second setting value. Claim No. 1 characterized in that the functional relationship is
A control device for a system including the prime mover and hydraulic pump described in item 1). (3) A control device for a system including a prime mover and a hydraulic pump according to claim (2), wherein the increased rotational speed signal increases or decreases in proportion to the rotational speed deviation.