JP2981339B2 - Control method of actuator driven by hydraulic source pump for construction machine - Google Patents

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 an engine for driving a hydraulic pump for generating hydraulic pressure for driving a hydraulic actuator for construction machinery, and more particularly to a method for controlling a hydraulic pump for a hydraulic actuator used in construction machinery. The present invention relates to a control method of an engine that controls the number of revolutions of the engine according to an operation state.

[0002]

2. Description of the Related Art In a conventional control method of an engine for driving a hydraulic pump for generating a hydraulic pressure for driving a hydraulic actuator for construction equipment, for example, a Japanese patent application
As shown in the specification and drawings of Japanese Patent Publication No. 55-42840, the operating lever for operating the hydraulic actuator by the driver is placed in a position where all the hydraulic actuators are stopped for a predetermined time or more. When it is detected that the engine is running, the engine speed is reduced from the normal operation speed, and after the engine speed is reduced in this way, the operating lever is operated so that at least one hydraulic actuator is operated from a stop. Is moved from the position where the hydraulic actuator is stopped, the change in the position of the operation lever is sensed and the engine speed is returned to the normal operation speed. In this conventional method, the control of the engine speed is performed only on the basis of the position of the operating lever operated by the driver.

[0003]

In the above conventional method, the control of the engine speed for driving a hydraulic pump for generating a hydraulic pressure for driving a hydraulic actuator is performed by:
Since the operation is performed only based on the position of the operation lever operated by the driver, the operation is performed irrespective of the actual operating state of the hydraulic pump or the actual load of the engine that drives the hydraulic pump for driving the hydraulic actuator. Will be Therefore, although the operation lever is placed in a position where all the hydraulic actuators are stopped for a predetermined time or more, unexpected power, that is, an engine load is required to maintain the hydraulic pressure by the hydraulic pump. In such a case, the engine speed is also reduced. On the other hand, after the operation lever is placed at a position where all the hydraulic actuators are stopped for a predetermined time or more and the engine speed is reduced, at least one hydraulic actuator is operated from the stop. Even if the operation lever is moved from the position where the hydraulic actuator is stopped, the speed at which the hydraulic actuator is actually operated is very low, and the output of the hydraulic pump required to drive the hydraulic actuator, that is, the load on the engine, Even if there is little change in the output of the hydraulic pump, that is, the load of the engine when the operating lever is in the position where all the hydraulic actuators are stopped, the engine speed is increased. As described above, in the conventional method, an inappropriate decrease in the engine speed and an unnecessary increase in the engine speed occur. According to the control of the present invention of the engine speed for driving the hydraulic pump for generating the hydraulic pressure for driving the hydraulic actuator, the occurrence of an inappropriate decrease in the engine speed and an unnecessary increase in the engine speed are prevented. Is done.

[0004]

According to the present invention, when the load of an engine for driving a hydraulic pump for generating hydraulic pressure for driving a hydraulic actuator for construction equipment is less than a first predetermined value, or When a command to stop all hydraulic actuators is input to a hydraulic valve disposed between the hydraulic pump and the hydraulic actuator and controlling the operation and stop of the hydraulic actuator, and when the command is held for a predetermined time or more, fuel supply to the engine is stopped. When the load for driving the hydraulic pump exceeds a second predetermined value after the supply has been reduced and the engine speed has been reduced, and thus the engine speed has been reduced, fuel is supplied to the engine. Increase supply and increase engine speed.

[0005]

According to the present invention, when the load of the engine for driving the hydraulic pump is less than the first predetermined value, or between the hydraulic pump and the hydraulic actuator, the hydraulic valve for controlling the operation and stop of the hydraulic actuator is provided. When a command to stop all the hydraulic actuators is input and the command is held for a predetermined time or more, the fuel supply to the engine is reduced, the engine speed is reduced, and thus the engine speed is reduced. After that, when the load of the engine for driving the hydraulic pump exceeds a second predetermined value, the supply of fuel to the engine is increased and the engine speed is increased. Regardless of the position of the operating lever, the engine speed can be increased again according to the load of the engine for driving the hydraulic pump. Increasing the supply of fuel. Claim 1
In the present invention described in the above, the operation lever is placed in a position where all the hydraulic actuators are stopped for a predetermined time or more, but unexpected power, that is, engine Is required, the load on the engine that drives the hydraulic pump is less than the first predetermined value, so that the engine speed is not reduced. On the other hand, in the present invention described in both Claims 1 and 2, the hydraulic actuator is disposed when the load of the engine for driving the hydraulic pump is less than a predetermined value or when the hydraulic pump is disposed between the hydraulic pump and the hydraulic actuator. After a command to stop all hydraulic actuators is input to the hydraulic valve that controls the operation and stop of the engine and the command is held for a predetermined time or more, the engine speed is reduced, and at least one hydraulic actuator is Even if the operating lever is moved from the position where the hydraulic actuator is stopped so that the hydraulic pump is operated from the stop, if the load of the engine for driving the hydraulic pump does not exceed the second predetermined value, the fuel supply to the engine is stopped. Since it does not increase the engine speed by increasing the supply,
When the operation speed of the hydraulic actuator is very low and the output of the hydraulic pump required to drive the hydraulic actuator, that is, the load of the engine, is in a state where the operation lever is located at a position where all the hydraulic actuators are stopped. When the output of the hydraulic pump at the time, that is, the load of the engine hardly changes, the engine speed does not increase. As described above, in the present invention, an inappropriate decrease in the engine speed and an unnecessary increase in the engine speed are prevented, and the engine speed is appropriately controlled in accordance with the output actually required for the engine. Is done.

[0006]

FIG. 1 shows an actuator drive control device in a construction machine to which the present invention is applied. Usually, one of a plurality of actuators 1 is illustrated, and the operation of the actuator 1
Is controlled by a high-pressure hydraulic valve 2 that controls the flow of high-pressure hydraulic pressure output from the high-pressure hydraulic pump 4 and the flow of hydraulic pressure from the actuator 1. The operation of the high-pressure hydraulic valve 2 is controlled by the low-pressure hydraulic pressure output from the low-pressure hydraulic pump 5 controlled by the pilot valve 3, and the output hydraulic pressure from the low-pressure hydraulic pump 5 depends on the inclination of the operating lever 6 from the upright position. It is almost proportional to θ. Therefore, the operation of the actuator 1 is controlled by the operating lever 6 operated by the driver via the pilot valve 3 and the high-pressure hydraulic valve 2. Generally, when the inclination degree θ is zero, the operation of the actuator 1 is stopped. That is, the inclination degree θ of the operation lever 6
Is zero, a command to stop the hydraulic actuator 1 is generally output from the operation lever 6 to the pilot valve 3 and the high-pressure hydraulic valve 2.

The high-pressure hydraulic pump 4 and the low-pressure hydraulic pump 5 are driven by an engine 7 including a governor (not shown). The rotation speed of the engine 7 is adjusted by fuel supply controlled by a governor lever driving device 8 that drives a governor lever (not shown) of the governor. The fuel supply amount is controlled in accordance with the position of the governor lever controlled by the governor lever driving device 8. The position of the governor lever controlled by the governor lever driving device 8 is determined by the rotation speed detector 1 that measures the output rotation speed of the engine 7.
The output of 0 and the hydraulic pressure applied to the pilot valve 3 proportional to the operation inclination degree θ of the operation lever 6 are measured to detect that the operation of the actuator 1 has been stopped or that the operation of the actuator 1 has been commanded. Pressure gauge 1 to detect
1, the number of revolutions of the engine 7 (the number of revolutions when the engine 7 rotates without receiving a deceleration command according to the present invention and the fuel supply amount cannot be reduced, ie, the engine load state or the actuator The output of the accelerator setting device 12 for setting the reference rotation speed desired under no load on the engine 7 before the fuel supply amount is reduced according to the operation command state, and the AEC (automatic control) from the AEC setting device 13 Engine speed acceleration / deceleration control) The first stage (the degree of engine deceleration is small depending on the engine state or the engine state command) and the second stage (the degree of engine deceleration is large depending on the engine state or the engine state command). Control is performed by the control device 9 in accordance with the specified output. NL ₁ and NL ₂ specified via the AEC setting unit 13 can be set to arbitrary values.

A method of controlling the number of revolutions of the engine 7 by controlling the fuel through the governor driving device 8 and the governor lever by the control device 9 in the present invention will be described below.

Hereinafter, specific examples of various set values used in one embodiment of the present invention will be described.・ Set speed: A _CCEL = No load speed at each accelerator position ・ Medium speed operation command value: N _M1 = A _CCEL -100 rpm (at AECI stage): N _M2 = A _CCEL -100 rpm (at AECII stage) ) and low speed operation command value: when N _L1 = A _CCEL -100rpm (AECI stage): N _L2 = 1300 rpm (at AECII stage) and light load judging revolution number: N ₁₁ = Na- 10rpm (at AECI stage): N ₂₁ = Na-10 rpm (at AECII stage) in the load judgment rotation speed (at AECI _{stage) N 12 = Na-50rpm:} N 22 = Na-50rpm ( at AECII stage) heavy load judgment rotation speed and low speed operation setting restoration judgment rotation speed: N ₁₃ = Na-70rpm (at AECI _{stage): N 23 = Na-70rpm} ( at AECII stage) and medium speed operation setting restoration judgment rotation _{speed: N 14 = Na-70rpm (} A When CI _{stage): N 24 = Na-70rpm} ( at AECII stages) each governor lever position idling speed: Na (varies according to each governor lever position) (supplied to the engine fuel from the governor in accordance with the governor lever position The speed at which the engine rotates at a higher speed if there is no load on the engine at that time.
Na is calculated based on the relationship between the predetermined governor lever position and the no-load rotation speed Na according to the operated position of the governor lever measured by the governor lever position detector 14.・ Light load judgment time: T _1A = 3 seconds (when AECI stage): T _2A = 3 seconds (when AEC II stage) ・ Medium load judgment time: T _1B = 10 seconds (when AECI stage): T _2B = 10 seconds (At AECII stage)

The following describes the relationship between the load state when the first stage of AEC is selected and the engine control method when various setting values are set as described above. Operator selection status is A
It is assumed that the first stage of EC is selected and the full accelerator (A _CCEL = 2000 rpm) position is selected as the accelerator position. When the AEC 2 stage is selected, the following relationship is applied only by changing the set values. The portions indicated by the alphabetic characters correspond to the flowchart portions in FIGS. 2, 3, 4, and 5. 1. Relationship between load condition and engine control method when low speed operation command is issued 1) Load condition and engine control method when changing from heavy load condition to light load condition

[Table 1]

(I) Heavy load condition Now, in the governor lever state for supplying fuel for the set rotation operation (full accelerator), Ne = 1800 rpm
In a heavy load state where the engine actually rotates. First A
The section processes various input signals, and sets the respective set values as follows. -AEC SW = I stage-A _CCEL = 2000 rpm-Ne = 1800 rpm-Na = A _CCEL = 2000 rpm Since the AEC I stage is selected, the flow is A → B →
The flow proceeds from C to D, and the following settings are made in D.・ N ₁₁ = Na-10 rpm = A _CCEL -10 rpm = 19
_{90rpm · N 12 = Na-50rpm} = A CCEL -50rpm = 19
_{50rpm · N 13 = Na-70rpm} = A CCEL -70rpm = 19
_{30rpm · N 14 = Na-70rpm} = A CCEL -70rpm = 19
30 rpm The operation state judgment unit E is in the set rotation operation.
Branch to S. Ne = 18 in the light load determination unit F
Since 00 rpm <N ₁₁ 1990 rpm, true (N
e> N ₁₁ ) does not hold and the flow branches to NO.
Light load elapsed time counter is cleared in part J
T ₁₁ = 0. Further, in the medium load determination unit K, Ne =
Ne> 1800 rpm <N ₁₂ = 1950 rpm
N ₁₂ branches to NO not satisfied. At O, the middle load elapsed time measurement counter is also cleared and T ₁₂ = 0. In this flow, the operation command arrives at the set rotation operation command section P, and the operation is maintained as instructed by the accelerator.
The flow returns to Start again.

(Ii) Light load transition state (from when the load on the engine is reduced to immediately before the engine speed is reduced) Here, it is assumed that the load state has changed from heavy load to light load. As the light load, a no-load neutral state is assumed. The actual engine speed Ne is 1800 rpm → 200
0 rpm (no-load rotation speed). The flow is A → B →
C → D flows. Since the governor lever position remains set before, in A, Na = A _CCEL = 2000r
pm. Therefore, even in D, N ₁₁
Each value of N ₁₂ N ₁₃ N ₁₄ does not change, and the value of the flow (i) is maintained. Since E is the set operation state, the process branches to YES as in the previous flow. Light load judgment device F
Then the flow changes. That is, Ne = 2000 rpm> N ₁₁
= 1990 rpm, Ne> N ₁₁ holds and Y
Branch to ES. At G, the light load elapsed time counter is counted up. For example, if one count is 0.02 seconds, T ₁₁ = 0.02 seconds. Light load elapsed time determining unit in H T ₁₁ = 0.02 seconds <T _1A
= 3 seconds, T ₁₁ > T _1A does not hold and the flow branches to NO. Ne = 2000rpm for medium load judgment unit K
> N ₁₂ = 1950 rpm, so branch to YES. At L, the middle load elapsed time measurement counter is counted up, and T ₁₂ = 0 → 0.02 seconds as with the light load. In the middle load elapsed time judgment device M, T ₁₂ = 0.0
2 seconds <T _1B = 10 seconds, so T ₁₂ > T _1B does not hold and N
After branching to O, it reaches P, and the set rotation (accelerator instruction) operation is still commanded, and the AEC does not operate yet.

(Iii) Start a low-speed operation command under a light load (neutral) state (when the load of the engine is small over a certain limit,
(When the number of revolutions of the engine starts to decrease.) When 151 cycles of the flow (ii) are continuously generated, a low-speed operation command is started. In this flow, A → B → C →
The flow from D → E → F flows in the same manner as the flow of (ii) above,
Light load elapsed time measuring counter G counts up the T ₁₁ = 3.02 seconds at 151 cycles.
In the light load elapsed time judgment device H, T ₁₁ = 3.02 seconds>
T _1A = 3 seconds, T ₁₁ > T _1A holds, and the flow is YE
It branches to S and the low speed operation is commanded for the first time at I. (Note that the middle load elapsed time holds the value of the previous 150th cycle, and T ₁₂ = 3.00 seconds.)

(Iv) Moving at a low speed operation position under a light load (neutral) state (a process in which the number of revolutions of the engine is reduced) Here, the first low speed operation command is issued in the previous flow (iii). This shows a state in which the governor lever is moving to a low speed by the governor lever driving device. As a specific example, a flow from the time when the governor lever is driven to the intermediate position between the setting and the low speed is shown. First, in A, unlike the case (iii), the value of Na changes because the governor lever is moved. For convenience of explanation, governor lever position and Na
If there is a linear relationship with (no-load rotation speed), since it is an intermediate position, N = (A _CCEL + N _L1 ) / 2 = (2000 + 1)
900) / 2 = 1950 rpm. (Note: Actually, there is no linear relationship due to governor and engine characteristics.
a is calculated. ) Assume that the actual engine speed in the no-load state is also Ne = 1950 rpm.
After the Na is updated in this way, the flow is B → C → D
And each value is determined by the load determination rotation speed setting device D. ・ N ₁₁ = Na-10 rpm = 1950 rpm-10 rpm
_{m = 1940rpm · N 12 = Na} -50rpm = 1950rpm-50rp
_{m = 1900rpm · N 13 = Na} -70rpm = 1950rpm-70rp
_{m = 1880rpm · N 14 = Na} -70rpm = 1950rpm-70rp
It is updated as m = 1880 rpm. Currently, a low-speed operation command is being issued, so the operation status judgment unit E returns NO, and the next Q returns YES.
Branch to Ne = 195 for the heavy load determiner R
0 rpm> N ₁₃ = 1880 rpm, and Ne <N ₁₃
Is not satisfied and the result is NO, and the operation state determiner S is YES because the vehicle is moving to a low speed. Further, in the light load determiner T, Ne = 1950 rpm> N ₁₁ = 1
940 rpm, Ne> N ₁₁ is satisfied, and YES
Then, at the branch I, the low speed operation (to be gradually moved to the low speed position) command is continued.

(V) Light load (neutral) state low-speed operation (when the engine maintains a low-speed operation speed in a desired range) The flow in a state where the governor lever finally reaches the low-speed operation position is shown. However, Ne = 1900 rpm.
In this operating state, Na at A has the following value. _{Na = N L1 = A CCEL -100rpm} = 2000rpm-
100 rpm = 1900 rpm That is, Na becomes the low-speed operation speed, flows in the order of B → C → D, and each value is set by the load judgment speed setting device D. ・ N ₁₁ = Na-10 rpm = 1900 rpm-10 rpm
_{m = 1890rpm · N 12 = Na} -50rpm = 1900rpm-50rp
_{m = 1850rpm · N 13 = Na} -70rpm = 1900rpm-70rp
_{m = 1830rpm · N 14 = Na} -70rpm = 1900rpm-70rp
It is updated as m = 1830 rpm. Since the low-speed operation command is still being issued, the operation status judgment unit E returns NO, and the next Q returns YES.
Branch to Ne = 190 for the heavy load determiner R
0 rpm> N ₁₃ = 1830 rpm and Ne <N ₁₃
Does not hold and the flow branches to NO. Operation state judgment device S
Is NO because the vehicle has reached a low speed.
Branch to In this manner, the low-speed operation is maintained in the no-load state.

2) Heavy load application during no-load low-speed operation (when a heavy load is applied to an engine that has entered low-speed operation due to continuous no-load state) FLOW (v) Start → A → B → C → D → E → Q → R → S →
I → Start (vi) Start → A → B → C → D → E → Q → R → P → Start

(V) During no-load low-speed operation (when fuel for performing low-speed operation at a substantially desired low-speed rotation is added to the engine) Here, the above-described no-load low-speed operation state is assumed to be continued. I do. The flow is 1. -1)-exactly the same as (v). Each constant / variable is as follows. · AEC SW = I stage _{· A CCEL = 2000rpm · Ne =} 1900rpm · Na = L L1 = 1900rpm · N 11 = Na- 1rpm = 1900rpm-10rp
_{m = 1890rpm · N 12 = Na} -50rpm = 1900rpm-50rp
_{m = 1850rpm · N 13 = Na} -70rpm = 1900rpm-70rp
_{m = 1830rpm · N 14 = Na} -70rpm = 1900rpm-70rp
m = 1830rpm · N ₁₁ = 3.02 seconds · N ₁₂ = 3.00 seconds

(Vi) Heavy load input (when heavy load is applied to the engine while fuel for low-speed operation is being added to the engine) During the previous flow (v) (during no-load low-speed operation), the engine It is assumed that a heavy load such that the rotation speed Ne = 1750 rpm is applied. When this load is applied, the governor lever is still in the low-speed operation position. Thus, at A: -AEC SW = I stage-A _CCEL = 2000 rpm-Ne = 1750 rpm-Na = N _L1 = 1900 rpm The flow continues from B → C → D →, and the previous value is held in D.・ N ₁₁ = Na-10 rpm = 1900 rpm-10 rpm
_{m = 1890rpm · N 12 = Na} -50rpm = 1900rpm-50rp
_{m = 1850rpm · N 13 = Na} -70rpm = 1900rpm-70rp
_{m = 1830rpm · N 14 = Na} -70rpm = 1900rpm-70rp
m = 1830 rpm Since the low-speed operation command is currently being issued, the operation state determiner E determines NO, and the next Q determines YES, and branches to R. Ne = 1750 rp for the heavy load determiner R
m <N ₁₃ = 1830 rpm and true (Ne <N ₁₃ )
Is established and the flow branches to YES. If it is determined that the load is heavy, the load reaches P without delay and the set operation is commanded immediately. After the set rotation operation command, the flow becomes the same as the flow (i) at the time of the heavy load described above. However, Ne and Na are updated each time the governor lever returns to the set rotation position. N ₁₁ , N ₁₂ , N ₁₃ , and N ₁₄ are also updated one by one according to the update of Na, and the load determination conditions of F and K are updated. In addition, load elapsed time in the light · T _11, T ₁₂ also
At the point when J and O pass for the first time, the value held last time is cleared to zero as follows, and it becomes possible to start counting up from zero seconds when the load becomes light or medium load.・ T ₁₁ = 3.02 seconds → 0 seconds ・ T ₁₂ = 3.00 seconds → 0 seconds

3) Medium load application (holding operation) during movement of the low-speed operation position (while the engine load is small and the no-load state continues and the engine speed is being reduced, the middle load is larger than the light load but smaller than the heavy load). FLOW (iv) Start → A → B → C → D → E → Q → R → S
→ T → I → Start (vii) Start → A → B → C → D → E → Q → R → S → T → U
→ Begin

(Iv) Light load (neutral) state During low-speed operation movement (an example of a state in which the engine speed is in the process of being reduced is a case where the engine speed is between the set speed and the low-speed operation command value). Here, the flow described above is used. -1) It is assumed to flow exactly in the same manner as (iv). That is, it is assumed that the governor lever is also at the intermediate position between the setting and the low speed. Therefore, Ne = 1
950 rpm Na = 1950 rpm.
The value at D is also the same.・ N ₁₁ = Na-10 rpm = 1950 rpm-10 rpm
_{m = 1940rpm · N 12 = Na} -50rpm = 1950rpm-50rp
_{m = 1900rpm · N 13 = Na} -70rpm = 1950rpm-70rp
_{m = 1880rpm · N 14 = Na} -70rpm = 1950rpm-70rp
m = 1880 rpm

(Vii) Medium load application (in the above state, when a medium load larger than the light load but smaller than the heavy load is applied) During the previous flow (iv) (during low-speed movement), the engine speed becomes N
_11> Ne> in N, such as become ₁₃ and the load has entered. As the engine speed, for example, Ne = 1920 rpm
And The input processor A has the following values. -AEC SW = I stage-A _CCEL = 2000 rpm-Ne = 1920 rpm-Na = = 1950 rpm Subsequently, the flow becomes B->C->D->, and D holds the previous value (iv). Since a low speed operation command is currently being issued, the operation state determiner E determines NO, and the next Q determines YES and branches to R. In the heavy load determiner R, Ne = 1920 rpm> N ₁₃ = 188
0 rpm and true (Ne <N ₁₃ ) is not established and NO
Branch to The operating state determiner S branches to YES because it is moving at a low speed. Further, in the light load determiner T, Ne = 1920 rpm <N ₁₁ = 1940
Ne> N ₁₁ is not established because of rpm, and the flow branches to NO to reach the operating condition command unit U, and a command to maintain the current governor lever position is issued. Assuming that the medium load state (that is, the holding state) continues for a while and then the load becomes the no-load state again (the engine speed Ne = 1920 → 1).
At that time, the flow becomes the flow of (iv), and Ne = 1950 rpm by the light load determiner T.
> N ₁₁ = 1940 rpm and Ne> N ₁₁ is satisfied, and the operation command becomes a low-speed operation command I from the holding state without delay, and the governor lever is driven again toward the low-speed operation position. Here, some supplementary explanations regarding the holding function will be given. The meaning of the light load determiner T is to branch the operation command into the following two together with the load determination by the heavy load determiner R described above. (A) Ne> N ₁₁ (light load condition) --- → Low speed operation command (b) N ₁₁ >Ne> N ₁₃ (intermediate condition of heavy / light load) --- → Current position holding command, that is, set speed ( Although the load is not heavy enough to return to (high speed), since a certain load is applied, from the viewpoint of the operability of the hydraulic excavator, the current governor lever position is maintained instead of being reduced to low speed.

2. Relationship between load condition and engine control method when middle speed operation command is issued 1) Load condition and engine control method when changing from heavy load condition to medium load condition

[Table 2]

(I) Heavy load condition -1) Similar to the flow of (i), actual rotation Ne =
A heavy load of about 1800 rpm is set. Each value becomes the next value as in the previous (i) flow, and finally becomes the set rotation command of P. · AEC SW = I stage _{· A CCEL = 2000rpm · Ne =} 1800rpm · Na = A CCEL = 2000rpm · N 11 = Na-10rpm = A CCEL -10rpm = 19
_{90rpm · N 12 = Na-50rpm} = A CCEL -50rpm = 19
_{50rpm · N 13 = Na-70rpm} = A CCEL -70rpm = 19
_{30rpm · N 14 = Na-70rpm} = A CCEL -70rpm = 19
30 rpm ・ N ₁₁ = 0 second ・ N ₁₂ = 0 second

(Ii) Medium load transition state (from the time when the load on the engine is reduced until immediately before the engine speed is reduced) Here, it is assumed that the load state has changed from heavy load to medium load. Also, as the medium load, a load of Ne = 1970 rpm is assumed. Engine speed Ne is 1800r
pm → 1970 rpm. The flow is A → B
→ C → D flows. Since the governor lever position is still set, in A, Na = A _CCEL = 2000 rpm
It has become. Therefore, even in D, N ₁₁ N ₁₂
Each value of N ₁₃ N ₁₄ does not change, and the flow value of (i) is maintained. Since E is the set operation state, the process branches to YES as in the previous flow. The flow changes in the light load determiner F. That is, Ne = 1970 rpm <N ₁₁ = 19
Since 90 rpm, Ne> N ₁₁ does not hold and N
Branch to O 2. Light load elapsed time counter J
The previous value is T ₁₁ = 0, but the clear operation is performed. In the medium load judgment device K, Ne = 1970 rp
Since m> N ₁₂ = 1950 rpm, the flow branches to YES. At L, the middle load elapsed time measurement counter is counted up, and T ₁₂ = 0 → 0.02 seconds.
In the middle load elapsed time judgment device M, T ₁₂ = 0.02 second <
Since T _1B = 10 seconds, T ₁₂ > T _1B is not established, and after branching to NO, the vehicle reaches P, and the set rotation (accelerator instruction) operation is still commanded, and the AEC does not operate yet.

(Iii) Start of a medium speed operation command under a medium load condition (when the engine load exceeds a certain time when the engine load is short and the engine speed starts to be reduced) The flow of the above (ii) is continuously performed for 501 cycles. When this occurs, a medium speed operation command is started. In this flow, A → B → C →
The flow from D → E → F → J → K is performed in the same manner as in the flow of (ii), and the counter for measuring the middle load elapsed time of L is counted up to T ₁₂ = 10.02 seconds at 501 cycles. In medium load elapsed time judging unit M T ₁₂ = 10.
02 seconds> T _1B = 10 seconds and T ₁₂ > T _1B holds
The procedure branches to YES and the medium speed operation is commanded for the first time at N. (Since the light load elapsed time has been cleared to zero, T ₁₁ = 0 seconds.)

(Iv) Moving at a low speed operation position under a medium load condition (the process of decreasing the engine speed) In this case, the governor lever is operated for the first time in response to a medium speed operation command issued in the previous flow (iii). The state in which the governor lever is moving to the medium speed by the driving device is shown. As a specific example, a flow from the time when the governor lever is driven to the intermediate position between the set speed and the middle speed is shown. First, in A, unlike the case (iii), the value of Na changes because the governor lever is moved. For convenience of explanation, governor lever position and Na
If there is a linear relationship with (no-load rotation speed), since it is an intermediate position, Na = (A _CCEL + N _M1 ) / 2 = (2000
+1900) / 2 = 1950 rpm. (Note: Since there is not always a linear relationship due to the governor and engine characteristics, the no-load speed Na is calculated by a function stored in advance.) The engine speed is Ne = 1
Suppose it is 920 rpm. After the Na is updated in this manner, the flow flows in the order of B → C → D, and the respective values are determined by the load determination rotational speed setting device D. ・ N ₁₁ = Na-10 rpm = 1950 rpm-10 rpm
_{m = 1940rpm · N 12 = Na} -50rpm = 1950rpm-50rp
_{m = 1900rpm · N 13 = Na} -70rpm = 1950rpm-70rp
_{m = 1880rpm · N 14 = Na} -70rpm = 1950rpm-70rp
It is updated as m = 1880 rpm. At present, a medium speed operation command is being issued, so the operation status judgment unit E returns NO, and the following Q also returns NO.
Branch to Ne = 1920 for the heavy load determiner V
rpm> N ₁₄ = 1880 rpm, Ne <N ₁₄ is not established, and the result is NO, and the operation state determiner W is moving to the medium speed, so the result is YES. Further, in the medium load determiner X, Ne = 1920 rpm> N ₁₂ = 19
00rpm next Ne> N ₁₂ is (to be moved to the middle speed position) medium speed operation at the branch N YES satisfied so that the instruction is continued.

(V) Medium-load operation Medium-speed operation (when the engine maintains the desired range of medium-speed operation speed) The flow of the state where the governor lever finally reaches the medium-speed operation position is shown. However, Ne = 1870 rpm.
In this operating state, Na at A has the following value. Na = N _M1 = A _CCEL -100 rpm = 2000 rpm
m−100 rpm = 1900 rpm, that is, Na becomes a medium speed operation speed, flows in the order of B → C → D, and each value is determined by the load judgment speed setting device D. N ₁₁ = Na−10 rpm = 1900 rpm−10 rpm
_{m = 1890rpm · N 12 = Na} -50rpm = 1900rpm-50rp
_{m = 1850rpm · N 13 = Na} -70rpm = 1900rpm-70rp
_{m = 1830rpm · N 14 = Na} -70rpm = 1900rpm-70rp
It is updated as m = 1830 rpm. Since the medium-speed operation command is still in progress, the operation status judgment unit E returns NO, and the following Q also returns NO.
Branch to Ne = 1870 for the heavy load determiner V
rpm> N ₁₄ = 1830 rpm, Ne <N ₁₄ is not established, and the flow branches to NO. In the operating state determiner W, since the vehicle has reached the medium speed, the determination is NO, and the operation branches directly to N. In this way, the medium speed operation is maintained in the medium load state.

2) Medium-load medium-speed operation During heavy-load application during medium-speed operation (when fuel for medium-speed operation is applied to the engine or when a heavy load is applied to the engine) FLOW (v) Start → A → B → C → D → E → Q → V → W →
N → Start (vi) Start → A → B → C → D → E → Q → V → P → Start

(V) Medium-load medium-speed operation (when fuel for medium-speed operation at a substantially desired medium-speed is added to the engine) Here, the medium-load medium-speed operation state continues. It is assumed that The flow is 2. -1)-exactly the same as (v). Each constant / variable is as follows. AEC SW = I stage A _CCEL = 2000 rpm Ne = 1870 rpm Na = N _M1 = 1900 rpm N ₁₁ = Na-10 rpm = 1900 rpm-10 rpm
_{m = 1890rpm · N 12 = Na} -50rpm = 1900rpm-50rp
_{m = 1850rpm · N 13 = Na} -70rpm = 1900rpm-70rp
_{m = 1830rpm · N 14 = Na} -70rpm = 1900rpm-70rp
m = 1830 rpm ・ N ₁₁ = 10.02 sec ・ N ₁₂ = 0.00 sec

(Vi) Heavy load application (when heavy load is applied to the engine during middle speed operation) During the previous flow (v) (medium load middle speed operation), the engine speed Ne becomes 1750 rpm. Suppose a heavy load is applied. When this load is applied, the governor lever is still in the medium speed operation position. Therefore, at A: -AEC SW = I stage-A _CCEL = 2000 rpm-Ne = 1750 rpm-Na = N _M1 = 1900 rpm Subsequently, the flow changes from B to C to D, and the previous value is held in D as well.・ N ₁₁ = Na-1 rpm = 1900 rpm-1 rpm
_{m = 1899rpm · N 12 = Na} -50rpm = 1900rpm-50rp
_{m = 1850rpm · N 13 = Na} -70rpm = 1900rpm-70rp
_{m = 1830rpm · N 14 = Na} -70rpm = 1900rpm-70rp
m = 1830 rpm Since the medium speed operation command is currently being issued, the operation state determiner E turns to NO, and the next Q also turns to NO and branches to V. Ne = 1750 rp for heavy load detector V
m <N ₁₄ = 1830 rpm and true (Ne <N ₁₄ )
Is established and the flow branches to YES. If it is determined that the load is heavy, the load reaches P without delay and the set operation is commanded immediately. After the set rotation operation command, the flow becomes the same as the flow (i) at the time of the heavy load described above. However, Ne and Na are updated each time the governor lever returns to the set rotation position. N ₁₁ , N ₁₂ , N ₁₃ , and N ₁₄ are also updated one by one according to the update of Na, and the load determination conditions of F and K are updated. In addition, load elapsed time in the light · T _11, T ₁₂ also
At the point when J and O pass for the first time, the value held last time is cleared to zero as follows, and it becomes possible to start counting up from zero seconds when the load becomes light or medium load.・ T ₁₁ = 10.02 seconds → 0 seconds ・ T ₁₂ = 0.00 seconds → 0 seconds

3) Load increase (holding operation) during movement of the medium-speed operation position (when the engine load is small and the engine load continues and the engine speed is reduced to the medium speed, a load larger than the medium load is applied. FLOW (iv) Start → A → B → C → D → E → Q → V → W
→ X → N → Start (vii) Start → A → B → C → D → E → Q → V → W → X → U
→ Begin

(Iv) Medium load state Moving at the medium speed operation position (as an example of the engine speed being reduced to the medium speed, the engine speed is set between the set speed and the medium speed operation command value. Here, the flow described above is used. -1) It is assumed to flow exactly in the same manner as (iv). That is, it is assumed that the governor lever is also at the intermediate position between the setting and the low speed. Therefore, Ne = 1
920 rpm Na = 1950 rpm.
The value at D is also the same.・ N ₁₁ = Na-10 rpm = 1950 rpm-10 rpm
_{m = 1940rpm · N 12 = Na} -50rpm = 1950rpm-50rp
_{m = 1900rpm · N 13 = Na} -70rpm = 1950rpm-70rp
_{m = 1880rpm · N 14 = Na} -70rpm = 1950rpm-70rp
m = 1880 rpm

(Vii) Medium load input (when a load larger than the medium load but smaller than the heavy load is applied while the engine speed is being reduced to the medium speed) During the previous flow (iv) (during the middle speed movement) ) The engine speed is N ₁₃
> And Ne> N ₁₄ to become such a load is entered. Assume that the engine speed is, for example, about Ne = 1890 rpm. The input processor A has the following values. -AEC SW = I stage-A _CCEL = 2000 rpm-Ne = 1890 rpm-Na = = 1950 rpm Subsequently, the flow becomes B->C->D-> and D holds the previous value (iv). At present, since the medium speed operation command is being issued, the operation state determiner E becomes NO, and the next Q also becomes NO and branches to V. In the heavy load determiner V, Ne = 1890 rpm> N ₁₄ = 1880
rpm becomes true (Ne <N ₁₄₎ branches to NO not satisfied. The operation state determiner W branches to YES because it is moving at the medium speed. Furthermore, medium load judgment device
In X, Ne = 1890 rpm <N ₁₃ = 1900 rpm
Since Ne> N ₁₂ is not established, the flow branches to NO and the operation condition command unit U is reached, and a command to maintain the current governor lever position is issued. If this load state (that is, the holding state) continues for a while and then returns to the medium load state (the engine speed Ne = 1890 → 192)
At this point, the flow becomes the flow of (iv), and Ne = 1920 rpm> N in the medium load determiner X.
₁₂ = 1900 rpm, and Ne> N ₁₂ holds,
The operation command becomes the medium speed operation command N without delay from the holding state, and the governor lever is driven again toward the medium speed operation position. Here, some supplementary explanations regarding the holding function will be given. The meaning of the medium load determiner X is to branch the operation command into the following two together with the load determination by the heavy load determiner V described above. (A) Ne> N ₁₂ (medium load state) --- → Medium speed operation command (b) N ₁₂ >Ne> N ₁₄ (middle state of heavy / medium load) --- → Current position holding command Although it is not heavy enough to return to (high speed), from the viewpoint of the operability of the excavator, the current governor lever position should be maintained instead of dropping to medium speed because a certain load is applied. I do. Changing the supply amount of fuel is performed by changing the position of the governor lever.In general, even if the position of the governor lever is maintained, the fuel supply amount changes according to the load. Instead of holding the current governor lever position, the governor lever may be operated to hold the current fuel supply amount.

As an embodiment of the no-load (neutral) state judging method, a method of using both the engine speed and the neutral detection pressure switch signal will be described. In the following description of the present embodiment shown in FIGS. 7 and 8, portions designated by alphabetic characters correspond to the flowchart portions in FIGS. Generally, during actual work such as excavation in a hydraulic excavator, the engine speed also fluctuates according to the load fluctuation. On the other hand, in the no-load (neutral) state, the engine speed stably stabilizes to a constant value except for an overshoot period immediately after the load is removed. Therefore, measuring the fluctuation amount of the engine speed can be one condition for determining the no-load state. That is, as described below, the logical product of the fluctuation value of the engine speed (stability determination result), the neutral detection pressure switch signal, and the result of the light load lapse determination is taken to instruct low-speed operation. In this method, even if a pressure switch failure (a disconnection or the like) occurs during the load, the engine speed is not stabilized due to the load fluctuation. There is another advantage to say.

1. Flow when AECI stage is selected Operator selection status: AEC = I stage Accelerator position = full accelerator (A _CCEL = 2000 rp)
m) 1. Low speed operation command 1) Heavy load → Light load

(I) Heavy Load State This flow is exactly the same as that described above. However, the pressure switch signal is turned on in the signal input processing section A.
(During load) or OFF (No load) is input.
Further, the pressure switch signal determination unit a is ON because of heavy load, and is different in that it bypasses b and branches to F. N ₁₁ by (that is, during loading) to bypass b is the value set by the governor lever position signal is maintained at D, it is the same as that described previously for use in subsequent light load determiner F .

(Ii) No-load transition state In the signal input section A, the engine speed Ne changes and the pressure switch signal changes from ON to OFF. The flow is as follows: B → C → D → E → a In part a, the pressure switch signal is OFF, so the flow branches to YES, and the light load determination rotation speed is N ₁₁ = Ne−δ in the calculation part b.
Is rewritten as In the light load judgment section F, the above N ₁₁
Always Ne> N ₁₁ branches to YES established by rewriting. Each the counter unit G c counted up by light load elapsed time and revolution number stability measuring time is T ₁₁ = 0.02 sec, T ₁₃ = 0.02 sec. In d, the stable measurement start time has not yet been reached. That is, T ₁₃ =
NO because 0.02 seconds _{1T 1STRT} = 1.8 seconds
And branch to f. Even at f, T _1STRT =
1.8 seconds> T ₁₃ = 0.02 seconds, and true is not established.
Branch to T ₁₁ = 0.02 seconds <T _1A = 3 seconds for
Branches to K, branches from a light load L, but is counted up T ₁₂ = 0.02 sec at L M
In this case, T ₁₂ = 0.02 sec <T _1B = 10 sec, so that true is not established, and the set rotation command is still maintained at P.

(Iii) Maintenance of no-load state (T ₁₃ = T _1STRT ) This flow describes a state 1.8 seconds (= T ₁₃ = T _1STRT ) after the load is _disconnected in the no-load setting operation command state. I do. The flow is A → B → C → D → E → a → b → F → G
T ₁₁ = 1.8 seconds in flows G and c, and T ₁₃
= 1.8 seconds. Rotation speed stability measurement start time judgment unit
In c, T ₁₃ = T _1STRT = 1.8 seconds, so Y
The flow branches to ES, and N _1STD = Ne = 2000 rpm is set as the measurement reference rotation speed by the measurement reference rotation speed setting device of e. At f, T ₁₃ > T _1STRT is not established, the flow branches to H, and the flow setting rotation command is maintained in the order of H → K → L → M → P.

(Iv) Maintenance of no-load condition-stable measurement time zone (T
In _1FNSH> T _13> T _1STRT) this flow, the maximum value and the minimum value variation value of the rotational speed is calculated to describe the situation that repeatedly update. Currently
T ₁₁ = T ₁₂ = T ₁₃ = 2.4 seconds. The flow is A →
B → C → D → E → a → b → F → G → c → d
In this case, since T ₁₃ = 2.4 seconds ≠ T _1STRT = 1.8 seconds, the result is NO (that is, the measurement reference rotation speed is not changed).
N _1STD = 2000 rpm is maintained. ) Branch to f. At f, T _1FNSH = 2.8 seconds> T ₁₃ > T
_1STRT = 1.8 seconds is established, the _flow branches to g, and the fluctuation value of the rotation speed is calculated. Here, the difference between the previously determined measurement reference rotation speed N _1STD = 2000 rpm and the current actual rotation speed is taken, compared with the past fluctuation maximum and minimum values during the main measurement period, and if necessary, the maximum value or The minimum value is updated and the stored value is always updated. In H, T ₁₁ = 2.4 seconds <T
_{Since 1A} = 3 seconds, the flow branches to K and the flow continues from L → M → P.

(V) Maintenance of No-Load State-After _{Elapse of} Stability Measurement Time (T _1A > T ₁₁ = T ₁₃ > T _1FNSH ) The situation where the rotation speed stability measurement time has passed but before the light load allowable elapsed time will be described. The current count is T ₁₁ = T
₁₃ = 2.9 seconds. The flow is A → B → C → D → E
→ a → b → F → G → c → d → f In flow f, H
And the speed fluctuation is no longer calculated. In H, since light load allowable elapsed time (T _1A ) has passed, K → L → M →
P and remains at the set rotation.

(Vi) Maintenance of No-Load State-After Allowable Light Load Elapsed Time (T ₁₁ = T ₁₃ > T _1A ) This flow describes a situation where a low-speed operation command is issued for the first time. The elapsed time is T ₁₁ = T ₁₃ = 3.02 seconds A →
B → C → D → E → a → b → F → G → c → d → f → H. In the light load allowable elapsed time judgment device H, T ₁₁ = 3.
Since 02 seconds> T _1A = 3 seconds, it becomes YES and h
Branch to In h, the maximum / minimum fluctuation values (M _AX1 , M _IN1 ) sorted by the rotation speed fluctuation value calculation unit above
Is used to calculate the maximum rotation speed fluctuation width N _DIFF .
Next, a stability determination is performed by the rotation speed stability determiner i.
If the maximum rotation speed fluctuation width N _DIFF is smaller than the determination reference value N _STAB , it is regarded as a stable state, and the low speed operation command I is reached. If N _DIFF <N _STAB does not hold, it is assumed that the load is on and branch to j,
Light load elapsed time and rotation speed stabilization measurement time counter
T ₁₁ T ₁₃ , and maximum / minimum rotation speed fluctuations M _AX1 , M
_{After IN1} is cleared to zero, it reaches P and the set rotation operation command is continued. In this case, the flow is (i
Returning to i), the stability determination is repeated again.

1) Heavy load application during no-load low-speed operation The flow is slightly different from the previous flow: A → B → C → D
→ E → Q → R → P That is, if any load is applied during the no-load low-speed operation regardless of the magnitude (that is, at the moment when the pressure switch is turned on), the operation returns to the set rotation operation unconditionally.

In the present invention, when the load of the engine is less than the first predetermined value, instead of reducing the supply of fuel to the engine and decreasing the engine speed, or in combination therewith (the following conditions and logics). A pressure gauge indicates that a command to stop all the hydraulic actuators has been input to the hydraulic valves 3 and 4, which are arranged between the hydraulic pump and the hydraulic actuator and control the operation and stop of the hydraulic actuator. 11 from the output,
The command is held for a predetermined time (the same as a time that is kept below a first predetermined value, which is a condition for reducing the engine speed based on the state of the load of the engine, may be maintained). At times, the supply of fuel to the engine may be reduced to reduce the engine speed. Further, by combining the above conditions with a logical product or a logical sum, when the variation range of the engine load is less than the predetermined range for a predetermined time or more, the fuel supply to the engine is reduced and the engine speed is reduced. May be reduced. In addition, after the engine speed is reduced in this way, in combination with them, the output of the pressure gauge 11 indicates that a command to operate at least one hydraulic actuator has been input to the hydraulic valves 3 and 4. And when a command to operate at least one hydraulic actuator is issued, the supply of fuel to the engine may be increased to increase the engine speed. The engine load may be measured from the actual output torque of the engine. The engine load may be measured from the output flow from the hydraulic pump. The fuel supply decrease prohibition command is further input, and when there is the fuel supply decrease prohibition command, the load of the engine that drives the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is less than the first predetermined value, or Even if a command to stop all the hydraulic actuators is input to the hydraulic valve and the command is held for a predetermined time or longer, the supply of fuel to the engine does not have to be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an actuator drive control system in a construction machine to which an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a part of a flowchart of one embodiment of a control method of a hydraulic pump driven engine according to the present invention.

FIG. 3 is a diagram showing a part of a flowchart of an embodiment of a control method of a hydraulic pump driven engine according to the present invention.

FIG. 4 is a diagram showing a part of a flowchart of one embodiment of a control method of a hydraulic pump driven engine according to the present invention.

FIG. 5 is a diagram showing a part of a flowchart of an embodiment of a control method of a hydraulic pump driven engine according to the present invention.

FIG. 6 is a diagram for explaining an embodiment of a control method of a hydraulic pump driven engine according to the present invention.

FIG. 7 is a diagram showing a part of a flowchart of an embodiment of a control method of a hydraulic pump driven engine according to the present invention.

FIG. 8 is a diagram showing a part of a flowchart of an embodiment of a control method of a hydraulic pump driven engine according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator 2 High-pressure hydraulic valve 3 Pilot valve 4 High-pressure hydraulic pump 4 5 Low-pressure hydraulic pump 6 Operating lever 6 7 Engine (including governor) 8 Governor lever drive 9 Controller 10 Rotational speed detector 11 Pressure gauge 11 12 Accelerator setting device 13 AEC setting device 14 Governor lever position detector

Continuation of the front page (56) References JP-A-4-112929 (JP, A) JP-A-61-142338 (JP, A) JP-B-5-40132 (JP, B2) JP-B-60-38561 (JP, A2) , B2) Japanese Patent Publication No. 62-57842 (JP, B2) Japanese Utility Model Publication No. 3-7592 (JP, Y2) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02F 9/20 F02D 29/00- 29/06 F02D 41/00-41/40 F15B 11/00

Claims (18)

(57) [Claims] The present invention relates to a control method of driving a hydraulic source pump of an actuator for construction equipment, wherein the engine load of an engine driving a hydraulic pump for driving a hydraulic actuator is controlled by the engine speed at no load in a set rotation operation. Determined from the difference between the actual engine speeds, if the engine load is maintained for a predetermined time at or below the first predetermined value, the fuel supply to the engine is reduced, the engine speed is reduced, and after the engine speed is reduced, A method for controlling an oil source pump of a hydraulic actuator for construction machinery, wherein when the engine load obtained by the same method is equal to or greater than a second predetermined value, the fuel supply to the engine is increased and the engine speed is increased. . 2. The method for controlling an oil source pump of a hydraulic actuator for construction equipment according to claim 1, wherein a plurality of first predetermined values are set, and the engine load is maintained at a predetermined value or less for a predetermined time. A method of controlling an oil source pump of a hydraulic actuator for construction equipment, wherein a plurality of engine speeds to be decelerated are set. 3. The control method for an oil source pump of a hydraulic actuator for a construction machine according to claim 1, wherein a plurality of second predetermined values are set. Method. 4. The method for controlling a hydraulic pump for a construction machine hydraulic actuator according to claim 1, wherein the second predetermined value is larger than the first predetermined value. How to control the source pump. 5. The method for controlling an oil source pump for a hydraulic actuator for construction equipment according to claim 1, wherein the amount of decrease in the engine speed obtained by reducing the supply of fuel to the engine is determined by a changeover switch. A method of controlling an oil source pump of a hydraulic actuator for construction machinery, wherein a plurality of values can be selected by switching. 6. The method for controlling an oil source pump of a hydraulic actuator for construction machinery according to claim 1, wherein the supply of pressurized oil to the hydraulic actuator after the engine speed decreases due to a decrease in fuel supply to the engine. A method for controlling an oil source pump of a hydraulic actuator for construction equipment, which instructs an engine to operate at a set number of revolutions when the engine is detected. 7. The method of controlling an oil source pump for a hydraulic actuator for construction equipment according to claim 1, wherein the engine load is reduced by reducing the fuel supply to the engine. The control method of the oil source pump of the hydraulic actuator for construction equipment, on condition that the load fluctuation range is maintained within a predetermined range for a certain period of time. 8. The method for controlling a hydraulic power source pump of an actuator for construction equipment according to claim 1, wherein the engine speed at no load in the set rotation motion is such that the amount of fuel supplied in the set rotation operation is equal to the hydraulic actuator. Is the engine speed at which the engine rotates at a higher speed if it is supplied when it is not operating.The actual engine speed in the set rotation operation is the actual engine speed reduced by the load that operates the hydraulic actuator. Control method, which is the number of rotations. 9. A method for controlling an engine for driving a hydraulic actuator pump for a construction machine, wherein a load on an engine for driving a hydraulic pump for generating a hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. , Reducing the supply of fuel to the engine, reducing the number of revolutions of the engine, and determining whether the load on the engine that drives the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. When determining, the load on the engine is
When the amount of fuel supplied at the time of the determination is supplied when the hydraulic actuator is not operating, the first rotational speed at which the engine rotates at a higher rotational speed, and at the time of the determination, the hydraulic actuator is turned off. Measured from the difference between the actual rotation speed of the engine lower than the first rotation speed by the load to be operated, and when the difference is smaller than a predetermined degree, it is determined that the load on the engine is lower than the first predetermined value; Control method. 10. A method for controlling an engine-driven pump for driving hydraulic actuators for a construction machine, wherein a load on an engine for driving a hydraulic pump for generating hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. Or, when a command to stop all the hydraulic actuators is input to a hydraulic valve that controls the operation and stop of the hydraulic actuator disposed between the hydraulic pump and the hydraulic actuator and the command is held for a predetermined time or more, the engine Reducing the supply of fuel to a predetermined amount to reduce the engine speed, and after the engine speed is reduced, the load of the engine for driving the hydraulic pump is equal to or greater than a second predetermined value. Increasing the fuel supply to the engine to increase the number of revolutions of the engine when The engine load for judging whether the load of the engine for driving the pump is equal to or greater than a second predetermined value is supplied to the engine for driving the hydraulic pump when the hydraulic actuator is not operating. The second speed, which is the speed at which the engine rotates at a higher speed when the amount of fuel is supplied, and the actual speed of the engine, which is lower than the second speed due to the load that activates the hydraulic actuator when judging. A control method, wherein the engine load is measured from a difference from a number, and when the difference is greater than a predetermined value, the engine load is determined to be equal to or greater than a second predetermined value. 11. A method of controlling an engine-driven pump for driving hydraulic actuators for a construction machine, wherein a load of an engine for driving a hydraulic pump for generating hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. Reducing the fuel supply to the engine to reduce the engine speed; and, after the engine speed is reduced, the load of the engine for driving the hydraulic pump is equal to or greater than a second predetermined value. When the fuel supply to the engine is increased, the fuel supply to the engine is gradually reduced, and the fuel supply to the engine is gradually reduced. In the above, when the load for driving the hydraulic pump is equal to or more than the first predetermined value, but is less than the second predetermined value, the supply of fuel to the engine is reduced. To stop the thing, control method. 12. A method of controlling an engine hydraulic drive pump drive engine for a construction machine, wherein a load of an engine for driving a hydraulic pump for generating a hydraulic pressure for driving a hydraulic actuator is less than a predetermined value, and A control method for reducing the supply of fuel to the engine and reducing the engine speed when a time during which the load fluctuation range or the engine speed fluctuation range is less than the predetermined range continues for a predetermined time or more. 13. The method of controlling a hydraulic pump driven engine according to claim 9, wherein a load of an engine that drives a hydraulic pump that generates a hydraulic pressure for driving a hydraulic actuator is less than a first predetermined value. In addition, when a command to stop all the hydraulic actuators is input to a hydraulic valve that is disposed between the hydraulic pump and the hydraulic actuator and controls the operation and stop of the hydraulic actuator, the supply of fuel to the engine is reduced to reduce the rotation of the engine. A control method that reduces the number. 14. A control method for a hydraulic pump drive engine according to claim 9, wherein the load of the engine for driving the hydraulic pump for generating a hydraulic pressure for driving the hydraulic actuator is a first load. And a command to stop all the hydraulic actuators is input to a hydraulic valve disposed between the hydraulic pump and the hydraulic actuator and controlling the operation and stop of the hydraulic actuator, and the command is longer than a predetermined time. A control method that, when held, reduces the supply of fuel to the engine and reduces the engine speed. 15. The control method for a hydraulic pump drive engine according to claim 9, wherein a load for driving the hydraulic pump is less than a predetermined value, or After the command to stop all the hydraulic actuators is input to the valve and the command is held for a predetermined time or more, the load for driving the hydraulic pump is reduced to a second predetermined value after the engine speed is reduced. When a command to operate at least one of the hydraulic actuators is input to a hydraulic valve, which is disposed between the hydraulic pump and the hydraulic actuator and controls the operation and stop of the hydraulic actuator, is input to the engine. Increase the supply of fuel and increase the engine speed,
Control method. 16. The method for controlling a hydraulic pump driven engine according to claim 10, wherein all hydraulic actuators are stopped by a hydraulic valve disposed between the hydraulic pump and the hydraulic actuator and controlling operation and stop of the hydraulic actuator. When a command is input and the command is held for a predetermined time or more, and the time when the fluctuation range of the load is less than the predetermined range continues for a predetermined time or more, the supply of fuel to the engine is reduced and the engine speed is reduced. Reduce the control method. 17. The control method for a hydraulic pump driven engine according to claim 9, wherein a load on an engine that drives a hydraulic pump that generates a hydraulic pressure for driving a hydraulic actuator is less than a first predetermined value. A hydraulic pump for reducing fuel supply to the engine and decreasing the engine speed when the time exceeds a predetermined amount and the load fluctuation range is less than the predetermined range for a predetermined time or more. Control method of driving engine. 18. A method for controlling a hydraulic pump driven engine according to claim 9, wherein the load of the engine for driving the hydraulic pump for generating a hydraulic pressure for driving the hydraulic actuator is the first. And a command to stop all the hydraulic actuators is input to a hydraulic valve disposed between the hydraulic pump and the hydraulic actuator and controlling the operation and stop of the hydraulic actuator, and the command is longer than a predetermined time. A control method for reducing the supply of fuel to the engine and reducing the engine speed when the time during which the load fluctuation range is kept and the load fluctuation range is less than a predetermined range has continued for a predetermined time or more.