JPH09151757A - Equipment and method of controlling number of revolution of engine of hydraulic type construction equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent noises and save fuel by detecting the neutral position of a valve, and keeping the engine speed at a low value when a hydraulic construction machine is not operated based on it. SOLUTION: This engine speed control device is provided with a means 19 for detecting the engine speed, a means 21 for adjusting the engine speed, a means 17 for detecting the pressure in a passage, and a control means 23 for reducing the engine speed with the engine speed adjusting means 21 when valves 7a-7f are judged to be at the neutral position through the prescribed functional calculation of the pressure value detected by the pressure detecting means 17 and prescribed set value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine speed control method and control method for a hydraulic construction machine, which detects a neutral position of a valve and utilizes the neutral position to control an engine while the construction machine is not operated. The present invention relates to a control device and a control method capable of preventing noise and saving fuel by rotating at a low speed.

[0002]

2. Description of the Related Art Generally, in a hydraulic construction machine, each working device of the construction machine operates, travels, and swings.
A device (hereinafter, the term "Auto-Deceleration" can be used) that automatically reduces the engine speed when no operation such as is performed is adopted.

As a known technique in the literature for this, 19
Japanese Patent Publication No. 85-38561 filed on September 2, 1985
No. and the like. According to this patented technology, the neutral position of the operating lever (a means for operating the work device and running, swinging, etc.) is detected, and when the neutral position is detected for a certain period of time, the engine speed is set as a reference value. It is controlled so that the speed is reduced to a lower speed.

[0004]

However, the above technique requires a plurality of detecting means for detecting the neutral position of a plurality of operating levers (Lever), and further reduces the engine speed after a certain period of time. Therefore, since a separate time measuring means (timer) is required, there is a drawback that a large number of parts are required. Also, since a series of these operations for reducing the engine speed and recovering the reduced engine speed are judged on the basis of a specific point on the operational advantage of the operating lever, frequent malfunctions occur, There was a disadvantage that flexibility in control could not be added. That is, the change from the working state to the neutral position and the change from the neutral position to the working state must be detected accurately at the time of the change, but the displacement of the operating lever and the state of the valve (position of the valve spool (Spool)). Etc.) may not accurately match due to processing error of the valve block, etc., so it is inaccurate to judge the presence or absence of the neutral state of the valve only by detecting the position of a specific point on the operation lever displacement. It may cause operation. Therefore, when it is automatically decelerated at an undesired time or when the work device is re-operated,
There were problems such as delay in recovery of engine speed.

The present invention has been made to solve the above-mentioned problems in the prior art, and an object of the present invention is to make the automatic deceleration function more accurate with a simple structure to allow smooth work progress. Another object of the present invention is to provide an engine speed control device and control method for a hydraulic construction machine, which can achieve fuel saving and noise prevention effects.

[0006]

According to one aspect of the present invention for attaining the above object, an engine and at least one hydraulic pump (Pum) driven by the engine are provided.
p), at least one or more actuators actuated by this hydraulic pump, at least one or more valves that determine the flow rate and direction at each of these actuators, and from the hydraulic pump to each of the above valves. Alternatively, in an engine speed control device for a hydraulic construction machine equipped with a flow path that connects in series at least one or more auxiliary valves that are operated together with each of the above valves, the speed of the engine is detected. Means for adjusting the number of revolutions of the engine, means for detecting the pressure in the flow passage, and a predetermined function of the pressure value detected by the pressure detection means and a predetermined set value. When it is determined through calculation that the valve is in the neutral position, the engine rotational speed adjusting means reduces the engine rotational speed by a control means. Hydraulic construction machine engine speed control device that is provided.

According to a preferred feature of the above-mentioned one aspect of the present invention, the control means includes a storage means for storing a work reference engine speed and the engine speed detected by the engine speed detecting means. When the engine speed reduced by the number adjusting means is compared with the work reference engine speed and the error is accumulated, and the error accumulated by the arithmetic means is equal to or larger than the preset reference value. Command means for instructing the engine speed control means to drastically reduce the engine speed to an idle speed.

According to another aspect of the present invention for attaining the above object, an engine, at least one or more hydraulic pumps driven by the engine, and at least one or more hydraulic pumps operated by the hydraulic pumps. Actuators, at least one valve that determines the flow rate and direction of each actuator, a flow path that connects the above-mentioned valves in series from the hydraulic pump, and the number of revolutions of the engine. In the method for controlling the engine speed of the hydraulic construction machine, the method for controlling the engine speed of the hydraulic construction machine, the method for detecting the pressure in the flow path, and the means for adjusting the engine speed. Whether or not the valve is neutral is determined based on the pressure value detected by the pressure detecting means, and when the valve is neutral, the engine speed detected by the engine speed detecting means is determined. Number and a predetermined work standard engine speed, the error is accumulated, and when the accumulated error exceeds a predetermined reference value, the engine speed is reduced to an idle speed. A method for controlling an engine speed of a construction machine is provided.

According to a preferred feature of the above-mentioned other aspect of the present invention, in the above-mentioned control method, the valve is operated through a function operation of the pressure value detected by the input detection means and a predetermined set value. A first step of determining whether all are in the neutral position, and a second step of reducing the engine speed minutely through the engine speed adjusting means when it is determined to be the neutral position in the first step; A third step of detecting the engine speed reduced in the second step through the engine speed detecting means, and the engine speed detected in the third step as the work reference engine speed. A fourth step of comparing and calculating the error and accumulating the error, comparing the error accumulated in the fourth step with the predetermined reference value and exceeding the fourth value, the engine speed adjustment hand Through a fifth step of reducing the engine speed to idling speed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a configuration to which an engine speed control device according to an embodiment of the present invention is applied.

As shown in FIG. 1, an engine 1 as a drive source and a hydraulic pump 3 driven by the engine 1.
a, 3b and a plurality of these actuator hydraulic cylinders (Silinde) operated by these hydraulic pumps 3a, 3b.
r) and hydraulic motors (Motor) 5a, 5b, 5c, 5
Multiple valves 7 to determine flow rate and direction at d, 5e, 5f
a, 7b, 7c, 7d, 7e, 7f are provided. These valves 7a, 7b, 7c, 7d, 7e, 7f have their internal flow paths switched and connected by the movement of a spool (not shown), and the corresponding actuators 5a, 5b, 5c, 5
While supplying the flow rate to one port (Port) of d, 5e, and 5f, discharging the flow rate from the other port, the tank (T)
Is returned to the actuators 5a, 5b,
5c, 5d, 5e and 5f are operated. These valves are 7
When the spools a, 7b, 7c, 7d, 7e and 7f are in the neutral position, the flow rate discharged from the hydraulic pumps 3a and 3b is immediately returned to the tank (Tank) through the bypass flow passages 9a and 9b. It

On the other hand, each of these valves 7a, 7b, 7c, 7
Auxiliary valves 11a, 11b, which are directly connected to d, 7e, 7f, and which cause the internal flow path to switch between a closed state (during operation) and an open state (during neutral state) in association with the movement of the spool described above.
11c, 11d, 11e, 11f are installed, and the flow path 1
3 is these auxiliary valves 11a, 11b, 11c, 11d, 1
1e and 11f are connected in series. One end of the flow path 13 is connected to the pilot pump 15 driven by the engine 1 described above, and the other end is connected to the tank (T).
Each of these valves 7a, 7b, 7c, 7d, 7e, 7f described above.
When the spool is in a neutral state, the internal flow paths of these auxiliary valves 11a, 11b, 11c, 11d, 11e, and 11f are open, so the pressure in the flow path 13 is "0". Have. That is, the pilot pump (Pilo
The discharge flow rate of the t pump 15 is returned to the tank (T) through the flow path 13 without resistance.

On the other hand, the above-mentioned valves 7a, 7b, 7
When one of the spools c, 7d, 7e and 7f is operated, the internal flow path of the auxiliary valve of the operated valve is closed and the pressure in the flow path 13 is increased. On the contrary, when the above-mentioned valves 7a, 7b, 7c, 7d, 7e and 7f are operated, the internal flow path of the auxiliary valve is further opened when the valve is switched to the neutral position, and the inside of the flow path 13 is opened. The pressure is further reduced to "0".

In the flow path 13, the flow path 13 as described above is provided.
A pressure detection unit 17 for detecting a change in pressure inside is provided. A normal pressure switch (Switch) that detects a constant pressure can be used in the pressure detection unit 17, but preferably a pressure sensor (Sensor) that can detect a continuous change in pressure is used.

On the other hand, the engine 1 is provided with an engine speed detector 19 for detecting the speed of the engine 1 and an engine speed adjuster 21 for adjusting the speed of the engine 1. The pressure detecting unit 17, the engine speed detecting unit 19, and the engine speed adjusting unit 21 are electrically connected to a control unit 23 having a built-in microcomputer.

The control unit 23 carries out all of these valves 7a, 7b, 7c, 7d, through a predetermined function calculation of the pressure value detected by the pressure detection unit 17 and a predetermined set value.
When it is determined that 7e and 7f are in the neutral position, the storage unit 23a that stores the work reference engine rotation speed by reducing the rotation speed of the engine 1 by the engine rotation speed adjustment unit 21 described above. The calculation unit 23b that compares the engine speed detected and reduced by the detection unit 19 with the above-described work reference engine speed and accumulates the error, and the error accumulated by the calculation unit 23b is preset and changeable. When the engine speed is equal to or higher than the reference value, the engine speed adjusting unit 21 includes a command unit 23c that orders the engine 1 to drastically reduce the engine speed to reach the idle speed.

The operation of the engine speed control system of the present embodiment constructed as described above will be described below.

After the pressure value in the flow path 13 detected by the pressure detecting unit 19 is approved by the control unit 23, all the pressure values using the function having the relationship of "S" as shown in FIG. 2 are used. It is determined whether these valves 7a, 7b, 7c, 7d, 7e, 7f are in the neutral position. This is faster and more accurate in detecting the pressure change, that is, the neutral position of the valve, than simply judging with a pressure value above a certain level as a reference.

When the neutral position is further detected, the control unit 2
In No. 3, if this is not a short rest period in the middle of continuous work, the engine speed is reduced, so that the engine speed is minutely changed (decreased) at a level that does not hinder the continuous work thereafter. A command signal is authorized from 23c to the engine speed adjustment unit 21.

The engine speed detector 19 further detects the changed engine speed, and the calculator 23b
An error between the work reference engine speed stored in the storage unit 23a and the changed engine speed is calculated, and the error is accumulated. When the neutral position continues without fluctuation, when the accumulated error due to the function relationship as shown in FIG. 3 due to the accumulated error becomes equal to or more than a preset predetermined reference value, the engine speed through the command unit 23c described above. According to a command from the adjusting unit 21, the engine speed is suddenly reduced to an idling speed. The above-mentioned reference value can be reset and changed. In this way, when the engine speed becomes the idling speed, the error accumulation is suspended and the engine speed is maintained at the idling speed. Even while such a process is in progress, the pressure detecting unit 17 continuously detects the pressure in the flow path 13, but at least one valve is operated by the detected pressure difference, and the neutral state is obtained. When it is determined that the engine is to be released, the control unit 23 changes (increases) the engine speed to the above-described work reference engine speed according to a command from the engine speed adjusting unit 21 through the command unit 23c, and accumulated error. Is erased to zero.

Next, a method for controlling the engine speed of the hydraulic construction machine according to the present invention will be described.

In step 1, these valves 7a, 7b, 7c, 7d, 7b, 7c, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7c, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 7d, 6d, 7d, 7d, 7d, 7d, 7D, 7D, 7D, 7D, 7-
It is determined whether all of 7e and 7f are in the neutral position.

In step 2, if the neutral position is determined in step 1 above, the engine speed is slightly reduced through the engine speed adjuster 21.

In step 3, the engine speed reduced in step 2 is detected by the engine speed detector 19 described above.

In step 4, the engine speed (Ncur) detected in step 3 is compared with the work reference engine speed (Nref) to calculate the error (E: E = Nref-Ncur), which is accumulated. Accumulated error ΣE: ΣE = E1 + E2 + ... E
n) In step 5, the error accumulated in step 4 is compared with a predetermined reference value (Eref).

In step 6, if the error (ΣE) accumulated as a result of the comparison in step 5 exceeds the reference value (Eref), the engine speed is reduced to the idling speed through the engine speed adjusting unit 21. Let If it is not exceeded, if it is determined to return to the stage 1 and the neutral state is continued in the stage 1, the process from the stage 2 to the stage 6 is repeated and it is determined to leave the neutral state. The engine speed adjusting unit 21 recovers the engine speed to the work reference engine speed and erases the accumulated error (ΣE) to zero.

In step 7, after the engine speed is reduced to the idling speed in step 6, the process returns to step 1 and if it is determined in step 1 that the engine is in a continuous neutral state, the idling speed is maintained, When it is determined to leave the neutral state, the error accumulated by recovering the engine speed to the work reference engine speed through the engine speed adjuster 21 and calculating the accumulated error (Σ
E) is erased so that it becomes zero.

[0029]

As described above, according to the present invention, it is possible to appropriately reduce the engine speed while the valve is not operated, and to expect the effects of noise prevention and fuel saving. The configuration can be greatly simplified by substituting a plurality of detecting means for detecting the neutral positions of the operating levers as a single pressure detecting means. Further, the judgment of the neutral position is not made by simply making a judgment based on a constant level ideal pressure value reservoir, but by making a judgment through a continuous pressure change rate and a function, a more accurate and quick judgment can be obtained. It is possible to take measures such as minute fluctuations due to the position of the operated valve and minute changes in pressure due to machining errors in the valve block, etc., only by appropriately changing the function formula, and to exert more precise and flexible control capability. it can.

[0030]

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an engine speed control device according to an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a pressure value of a valve neutral position detector and a neutral position determination reference value.

FIG. 3 is a graph showing a relationship between an accumulated engine speed error and an engine speed command value.

[Explanation of symbols]

1 engine 3a, 3b hydraulic pump 5a, 5b, 5c, 5d, 5e, 5f actuator 7a, 7b, 7c, 7d, 7e, 7f valve 9a, 9b bypass passage 11a, 11b, 11c, 11d, 11e, 11f auxiliary valve 13 flow path 15 pilot pump 17 pressure detection unit 19 engine speed detection unit 21 engine speed control unit 23 control unit 23a storage unit 23b operation unit 23c command unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02D 45/00 310 F02D 45/00 310J

Claims (8)

[Claims] 1. An engine, at least one or more hydraulic pumps driven by the engine, at least one or more actuators operated by the hydraulic pumps, and at least determining the flow rate and direction of each actuator. Hydraulic construction comprising one or more valves and a flow path connecting in series from the hydraulic pump each of the valves or at least one or more auxiliary valves operated in co-operation with the valves. In an engine speed control device for a machine, means for detecting the speed of the engine, means for adjusting the speed of the engine, means for detecting the pressure in the flow path, and pressure detection When it is determined that the valve is in the neutral position through a predetermined function calculation between the pressure value detected by the means and a predetermined set value, the engine speed adjusting means is notified to the engine speed adjusting means. Ri hydraulic construction machine engine speed control unit characterized in that it is constituted by a control means for reducing the rotational speed of the engine. 2. The control means stores the engine speed reduced by the storage means for storing a work reference engine speed and the engine speed adjusting means detected by the engine speed detecting means. Comparing with the reference engine speed of the above, the calculating means for accumulating the error, and when the error accumulated by the calculating means exceeds a preset reference value, the engine speed adjusting means causes the engine 2. The engine speed control device for a hydraulic construction machine according to claim 1, further comprising: command means for instructing to rapidly reduce the rotation speed of the engine to reach an idle speed. 3. The engine speed control device for a hydraulic construction machine according to claim 2, further comprising means for changing the reference value. 4. The control means calculates the function of the pressure value newly detected by the pressure detecting means after the engine speed reaches an idle speed and the predetermined set value. If it is determined that the valve is in the operating position through the above, the accumulated error is erased to 0 (zero), and the engine speed adjusting means adjusts the engine speed to the work reference engine. The engine speed control device for a hydraulic construction machine according to any one of claims 1 to 3, wherein the engine speed control device recovers the rotation speed. 5. An engine, at least one or more hydraulic pumps driven by the engine, at least one or more actuators actuated by each of the hydraulic pumps, and at least determining the flow rate and direction of the actuators. One or more valves, a flow path connecting the above valves from the hydraulic pump in series, means for detecting the number of revolutions of the engine, and for detecting the pressure in the flow path. In the neutral state of the valve according to the pressure value detected by the pressure detecting means, wherein the engine speed control method for a hydraulic construction machine comprises: When the valve is in the neutral position, the engine speed detected by the engine speed detecting means is compared with a predetermined work reference engine speed. Accumulated error, hydraulic construction machine engine control method characterized by accumulated errors decrease if it exceeds a predetermined reference value of the engine rotational speed to the idling speed. 6. The control method according to claim 1, wherein it is determined whether all the valves are in a neutral position through a function operation of the pressure value detected by the pressure detecting means and a predetermined set value.
If the neutral position is determined in the first step, the second step in which the engine speed is slightly reduced through the engine speed adjusting means, and the engine speed reduced in the second step is set to the neutral position. Comparing the engine speed detected in the third stage with the engine speed detecting means, the engine speed detected in the third stage with the work reference engine speed, calculating the error, and accumulating the error. 4 levels,
When comparing the error accumulated in the fourth step with the predetermined reference value and exceeding the predetermined reference value, a fifth step of reducing the engine speed to an idle speed through the engine speed adjusting means is included. An engine speed control method for a hydraulic construction machine according to claim 5. 7. The control method according to claim 5, wherein the engine speed is decelerated to the idling speed in the fifth step, then returns to the first step, and is determined to be a neutral state which is continued in the first step. When it is determined that the idle speed is maintained and the neutral state is to be released, the engine speed is restored to the work reference engine speed through the engine speed adjusting means, and The method for controlling the engine speed of a hydraulic construction machine according to claim 4, further comprising the step of eliminating accumulated errors to make them zero. 8. If the accumulated error in the fifth step does not exceed the predetermined reference value, the process returns to the first step and it is determined in the first step that the neutral state is maintained. ,
When it is determined that the neutral state is to be released by repeating the processes from the second stage to the fourth stage, the engine speed is restored to the work standard engine speed through the engine speed adjusting means. The method of controlling the engine speed of a hydraulic construction machine according to claim 6 or 7, further comprising the step of eliminating the accumulated error so that the accumulated error becomes 0 (zero).