JPH05187285A - Control method for engine driving actuator hydraulic source pump of construction machine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of an improper engine speed drop and an unnecessary engine speed increase by controlling the speed of an engine, according to the operation state of a hydraulic pump for a hydraulic actuator. CONSTITUTION:When the load of an engine for driving a hydraulic pump to generate hydraulic pressure is less than the first prescribed value, or an instruction for stopping all hydraulic actuators is inputted to a hydraulic valve positioned between the hydraulic pump and a hydraulic actuator for use to control the operation and stoppage of the actuator, and kept valid for or over the predetermined time, fuel supply to the engine is reduced to lower the speed thereof. Also, when a load to drive the hydraulic pump exceeds the second predetermined value after the engine speed is lowered, the fuel supply to the engine is increased to raise the speed thereof.

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 that generates hydraulic pressure for driving a hydraulic actuator for a construction machine, and more particularly to a hydraulic pump for a hydraulic actuator used in a construction machine. The present invention relates to an engine control method for controlling an engine speed according to an operating state.

[0002]

2. Description of the Related Art In a conventional control method of an engine that drives a hydraulic pump that generates hydraulic pressure for driving a hydraulic actuator for construction machinery, for example, Japanese patent application
As shown in the specification and drawings of Sho 55-42840, the operating levers for the driver to operate the hydraulic actuators are placed for a predetermined time or longer in a state in which all the hydraulic actuators are stopped. When the engine speed is detected, the engine speed is lowered from the normal operation speed, and after the engine speed is reduced in this way, at least one hydraulic actuator is operated from the 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 operating speed. In this conventional method, control of the engine speed is performed only based on the position of the operating lever operated by the driver.

[0003]

In the above-mentioned conventional method, the control of the engine speed for driving the hydraulic pump for generating the hydraulic pressure for driving the hydraulic actuator is performed as follows.
Since it is performed only based on the position of the operating lever operated by the driver, it is performed regardless 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. Be seen. Therefore, the operating lever is placed in a position to stop all hydraulic actuators for a predetermined time or longer, but unexpected power, that is, engine load is required to maintain the hydraulic pressure by the hydraulic pump. In this case, the engine speed will be reduced. On the other hand, at least one hydraulic actuator should be operated from the stop after the operating lever is placed in a position to stop all the hydraulic actuators for a predetermined time or more and the engine speed is reduced. Even if the operating 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 of the engine, Even if there is little change in the output of the hydraulic pump, that is, the load on the engine when the operating lever is in a position to stop all the hydraulic actuators, the engine speed is increased. As described above, in the conventional method, an inappropriate decrease in engine speed or an unnecessary increase in engine speed occurs. According to the control of the engine rotational speed for driving the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator according to the present invention, it is possible to prevent the inappropriate reduction of the engine rotational speed and the unnecessary increase of the engine rotational speed. To be done.

[0004]

According to the present invention, when the load of the engine driving the hydraulic pump for generating the hydraulic pressure for driving the hydraulic actuator for construction machinery is less than a first predetermined value, or When a command to stop all the hydraulic actuators is input to the hydraulic valve that is placed between the hydraulic pump and the hydraulic actuator and that controls the operation and stop of the hydraulic actuator, and the command is held for a predetermined time or longer, When the load for driving the hydraulic pump exceeds a second predetermined value after reducing the supply and reducing the engine speed, and thus the engine speed, Increase supply and increase engine speed.

[0005]

According to the present invention, the hydraulic valve which is arranged when the load of the engine for driving the hydraulic pump is less than the first predetermined value or is arranged between the hydraulic pump and the hydraulic actuator and controls the operation and stop of the hydraulic actuator. When a command to stop all hydraulic actuators is input to and the command is held for a predetermined time or longer, the fuel supply to the engine is reduced and 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, so that the hydraulic actuator is operated. The engine speed can be increased again according to the engine load for driving the hydraulic pump, regardless of the position of the control lever. Increasing the supply of fuel. Claim 1
In the present invention described in (1), the operating lever is placed in a position to stop all the hydraulic actuators for a predetermined time or longer, but unexpected power, that is, engine, is used to maintain the hydraulic pressure by the hydraulic pump. When the load of 1 is required, the load of the engine that drives the hydraulic pump is less than the first predetermined value, so the engine speed is not reduced. On the other hand, in the present invention described in both claims 1 and 2, the load of the engine for driving the hydraulic pump is less than a predetermined value, or the hydraulic actuator is arranged between the hydraulic pump and the hydraulic actuator. A command to stop all hydraulic actuators is input to the hydraulic valve that controls the operation and stop of the engine, and after the command is held for a predetermined time or more, the engine speed is reduced, and at least one hydraulic actuator Even if the operating lever is moved from the position where the hydraulic actuator is stopped so as to operate from the stop, if the load of the engine for driving the hydraulic pump does not exceed the second predetermined value, fuel of the engine Since it does not increase the supply and increase the engine speed,
The speed at which the hydraulic actuators are actually actuated is very low, and the output of the hydraulic pump required to drive the hydraulic actuators, that is, the engine load, is placed in a position where the operating lever stops all the hydraulic actuators. When the output of the hydraulic pump at that time, that is, the load of the engine hardly changes, the engine speed is not increased. As described above, in the present invention, inappropriate reduction of the engine speed and unnecessary increase of the engine speed are prevented, and the engine speed is appropriately controlled according to the output actually required for the engine. To be done.

[0006]

1 shows an actuator drive control device in a construction machine to which the present invention is applied. Normally, one of a plurality of actuators 1 provided is shown, and the operation of the actuator 1 is performed by the actuator 1
Is controlled by a high-pressure hydraulic valve 2 which 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 is the degree of 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. When the inclination degree θ is zero, the operation of the actuator 1 is generally stopped. That is, the inclination degree θ of the operating lever 6
When is zero, a command to stop the hydraulic actuator 1 is generally output from the operating 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 cover (not shown). The rotation speed of the engine 7 is adjusted by fuel supply controlled by a governor lever drive device 8 that drives a governor lever (not shown) of the governor. The fuel supply amount is controlled according to the position of the governor lever controlled by the governor lever drive device 8. The position of the governor lever controlled by the governor lever driving device 8 is the rotation speed detector 1 for measuring 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 stop of the operation of the actuator 1 is commanded, or the operation of the actuator 1 is commanded. Pressure gauge 1 to detect
1 output, the set rotation speed of the engine 7 (the rotation speed when the engine 7 receives the deceleration command according to the present invention and rotates with no load and without reducing the fuel supply amount, that is, the engine load state or the actuator The output of the accelerator setter 12 for setting the desired reference speed in the unloaded state of the engine 7 before the fuel supply amount is reduced according to the operation command state, the AEC (automatic) from the AEC setter 13 Engine speed acceleration / deceleration control) The first stage (the degree of engine deceleration depending on the engine state or the engine state command is small) and the second stage (the degree of engine deceleration depending on the engine state or the engine state command is large) It is controlled by the control device 9 according to the instructed output. NL ₁ and NL ₂ instructed via the AEC setter 13 can be set to arbitrary values.

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

Specific examples of various set values used in the embodiment of the present invention are shown below. - speed setting: A _CCEL = no-load rotational speed and medium-speed operation command value for each accelerator position (at AECI stage) N _M1 = A _CCEL -100rpm: when N _M2 = A _CCEL -100rpm (AECII stage ) ・ Low speed operation command value: N _L1 = A _CCEL -100 rpm (when AECI stage): N _L2 = 1300 rpm (when AEC II stage) ・ Light load judgment rotation speed: N ₁₁ = Na-10 rpm (when AECI stage): N ₂₁ = Na-10 rpm (at AECII stage) -Medium load determination rotation speed: N ₁₂ = Na-50 rpm (at AECI stage): N ₂₂ = Na-50 rpm (at AECII stage) -Heavy load determination rotation speed-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 If there is no load on the engine at the same time, the number of revolutions at which the engine will rotate at a higher speed.
Na is calculated according to the operated position of the governor lever measured by the governor lever position detector 14, based on the relationship between the predetermined governor lever position and the no-load rotation speed Na. ) ・ Light load judgment time: T _1A = 3 seconds (AECI stage): T _2A = 3 seconds (AECI II stage) ・ Medium load judgment time: T _1B = 10 seconds (AECI stage): T _2B = 10 seconds (At AECII stage)

The relationship between the load state and the engine control method when the AEC first stage is selected when various set values are set as described above will be shown below. Operator selection status is A
It is assumed that the EC1 stage is selected and the full accelerator (A _CCEL = 2000 rpm) position is selected as the accelerator position. When the AEC two-stage is selected, the following relationships are applied only by exchanging the setting values. The portion designated by the English letters corresponds to the flow chart portion 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 state Ne = 1800 rpm in the governor lever state for supplying fuel for the preset rotation operation (full accelerator)
Then, the engine is in a heavy load state where it actually rotates. First A
Various input signals are processed by the section and each set value is set as follows.・ AEC SW = I stage ・ A _CCEL = 2000 rpm ・ Ne = 1800 rpm ・ Na = A _CCEL = 2000 rpm AEC I stage is selected, so the flow is A → B →
The flow goes from C to D, and the next setting is made at D. _{· 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 Operation status judgment section E: Since the set rotation operation is in progress, YE
Branch to S. In the light load determination unit F, Ne = 18
Since it is 00 rpm <N ₁₁ 1990 rpm, it is true (N
e> N ₁₁ ) is not established, and the flow branches to NO.
The light load elapsed time measurement counter is cleared at J section
T ₁₁ = 0. Further, in the medium load determination unit K, Ne =
1800 rpm <N ₁₂ = 1950 rpm, so Ne>
N ₁₂ is not established and the process branches to NO. At O, the medium load elapsed time measurement counter is also cleared and T ₁₂ becomes 0. In this flow, the operation command reaches the set rotation operation command section of P, and the operation according to the accelerator instruction is maintained.
The flow goes back to the beginning.

(Ii) Light load transition state (from when the load of the engine becomes small to immediately before the engine speed is reduced) Here, it is assumed that the load state changes from heavy load to light load. It is also assumed that the light load is a no-load neutral state. Actual engine speed Ne is 1800 rpm → 200
It becomes 0 rpm (no-load rotation speed). The flow is A → B →
It flows as C → D. Since the governor lever position remains set previously, in A Na = A _CCEL = 2000r
It is pm. Therefore, even in D, N ₁₁
The values of N ₁₂ N ₁₃ N ₁₄ do not change and the value of the flow of (i) is maintained. Even in E, since it is in the set operation state, branch 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. Y
Branch to ES. At G, the light load elapsed time measurement counter is incremented. For example, if one count is 0.02 seconds, then T ₁₁ = 0.02 seconds. In the light load elapsed time judging device H, T ₁₁ = 0.02 seconds <T _1A
= 3 seconds, T ₁₁ > T _1A is not established, and the flow branches to NO. Medium load determination device K: Ne = 2000 rpm
Since> N ₁₂ = 1950 rpm, the flow branches to YES. At L 2, the medium load elapsed time measuring counter is incremented and T ₁₂ = 0 → 0.02 seconds as in the case of light load. In the medium load elapsed time judging device M, T ₁₂ = 0.0
Since 2 seconds <T _1B = 10 seconds, T ₁₂ > T _1B cannot be established N
After branching to O, it reaches P, and the set rotation (accelerator instruction) operation is instructed, and AEC still does not operate.

(Iii) Start of a low speed operation command in a light load (neutral) state (when the engine load is small, a certain limit is exceeded,
When the engine speed starts to decrease) When the flow of (ii) described above is continuously generated for 151 cycles, the low speed operation command is started. In this flow, A → B → C →
From D → E → F, the same flow as (ii) above,
At 151 cycles, the light load elapsed time measurement counter of G is incremented to T ₁₁ = 3.02 seconds.
In the light load elapsed time judging device H, T ₁₁ = 3.02 seconds>
T _1A = 3 seconds and 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 medium load elapsed time is the value at the 150th cycle last time, and T ₁₂ = 3.00 seconds.)

(Iv) Moving to a low speed operation position in a light load (neutral) state (a process in which the engine speed decreases) Here, in response to the first low speed operation command issued in the previous flow (iii). Shows the state where the governor lever is moving to a low speed by the governor lever drive device. As a specific example, the flow from the time when the governor lever is driven to the intermediate position from the setting to the low speed is shown. First, in A, unlike the above (iii), the value of Na changes because the governor lever is moved. For convenience of explanation, the governor lever position and Na
_Assuming that there is a linear relationship with (no-load speed), N = (A _CCEL + N _L1 ) / 2 = (2000 + 1) because it is an intermediate position.
900) / 2 = 1950 rpm. (Note: Actually, there is no linear relationship depending on the governor and engine characteristics.
a is calculated. ) It is also assumed that the actual engine speed in the no-load state is Ne = 1950 rpm.
After Na is updated like this, 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 rp
_{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 like m = 1880 rpm. Currently, a low speed operation command is being issued, so the operating status determiner E is NO, and the next Q is YES.
Branch to. In the heavy load judgment device R, Ne = 195
0 rpm> N ₁₃ = 1880 rpm and Ne <N ₁₃
Is not established, the result is NO, and the operating condition determiner S is YES because the vehicle is moving to a low speed. Furthermore, in the light load determination device T, Ne = 1950 rpm> N ₁₁ = 1
It becomes 940 rpm, and Ne> N ₁₁ is satisfied, and YES.
At branch I, the low speed operation (should gradually move to the low speed position) command is continued.

(V) Light load (neutral) state low speed operation (when the engine maintains a low speed operation rotation speed in a desired range) A flow when the governor lever finally reaches the low speed operation position is shown. However, Ne = 1900 rpm.
In this operating state, Na in A has the following values. Na = N _L1 = A _CCEL −100 rpm = 2000 rpm−
100 rpm = 1900 rpm That is, Na becomes a low-speed operation rotation speed, B → C → D flows, and each value is determined by the load determination rotation speed setting device D. ・ N ₁₁ = Na-10 rpm = 1900 rpm-10 rp
_{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 determiner E is NO, and the next Q is YES.
Branch to. In the heavy load determination device R, Ne = 190
0 rpm> N ₁₃ = 1830 rpm and Ne <N ₁₃
Does not hold and branches to NO. Operating status determiner S
Since it has reached a low speed, it becomes NO and directly I
Branch to. In this way, the low speed operation is maintained in the unloaded state.

2) Applying heavy load during no-load low-speed operation (when a heavy load is applied to the engine that has entered low-speed operation due to continuous no-load condition) 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 is added to the engine for low-speed operation at an almost desired low-speed revolution) Here, it is assumed that the above-mentioned no-load low-speed operation state continues. To do. The flow is 1. -1)-(v) is exactly the same. The constants and variables are 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 = 1830 rpm ・ N ₁₁ = 3.02 seconds ・ N ₁₂ = 3.00 seconds

(Vi) Heavy load injection (when heavy load is applied to the engine while fuel for low speed operation is applied to the engine) During the previous flow (v) (during no load low speed operation) It is assumed that a heavy load such that the rotation speed Ne = 1750 rpm is entered. When this load is applied, the governor lever is still in the low speed operation position. Therefore, in A, it becomes as follows.・ 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 at D. _{· N 11 = Na-10rpm =} 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 = 1830 rpm Since a low speed operation command is currently being issued, the operation status determiner E turns to NO, and the next Q turns to YES, branching to R. In the heavy load judgment device R, Ne = 1750 rp
m <N ₁₃ = 1830 rpm and true (Ne <N ₁₃ ).
Holds and branches to YES. If it is judged to be a heavy load, P will be reached without delay and an immediate command will be issued. After the set rotation operation command, the flow is the same as the above-mentioned flow (i) under heavy load. However, both Ne and Na are updated every time before the governor lever returns to the set rotation position. N ₁₁ , N ₁₂ , N ₁₃ , and N ₁₄ are updated one by one according to the update of Na, and the load judgment conditions of F and K are updated. Also, the light / medium load elapsed time T ₁₁ , T ₁₂
At the time of the first passage through J and O, the value held last time is cleared to zero as follows, and when it is in a light or medium load state, it is possible to start counting up from zero seconds.・ T ₁₁ = 3.02 seconds → 0 seconds ・ T ₁₂ = 3.00 seconds → 0 seconds

3) Medium load input (holding operation) during low-speed operation position movement (engine load is small and no load continues and engine speed is decreasing, while light load is higher but heavy load is lower). When load is applied) FLOW (iv) Start → A → B → C → D → E → Q → R → S
→ T → I → Begin (vii) Begin → A → B → C → D → E → Q → R → S → T → U
→ start

(Iv) Light load (neutral) state Moving at low speed (when the engine speed is between the set speed and the low speed operation command value, as an example of a state in which the engine speed is decreasing) ) Here, the above flow 1. -1) -Flows in exactly the same way as (iv). That is, it is assumed that the governor lever is also in the intermediate position between setting and low speed. Therefore Ne = 1
950 rpm Na = 1950 rpm.
The values in D are also the same. _{· N 11 = Na-10rpm =} 1950rpm-10rp
_{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 (in the above condition, when a medium load larger than a light load but smaller than a heavy load is applied) During the previous flow (iv) (moving at a low speed), the engine speed is N.
_It is assumed that a medium load such as ₁₁ >Ne> N ₁₃ is entered. The engine speed is, for example, Ne = 1920 rpm.
Suppose Input processing unit A has the following values.・ AEC SW = I stage ・ A _CCEL = 2000 rpm ・ Ne = 1920 rpm ・ Na = = 1950 rpm The flow continues from B → C → D → and the previous value (iv) is retained at D as well. Since a low speed operation command is currently being issued, the operation status determiner E turns to NO, and the next Q turns to YES, branching to R. In the heavy load determination device R, Ne = 1920 rpm> N ₁₃ = 188
It becomes 0 rpm and true (Ne <N ₁₃ ) is not established NO
Branch to. Since the operating condition determiner S is moving at a low speed, the flow branches to YES. Further, in the light load determination device T, Ne = 1920 rpm <N ₁₁ = 1940
Since it is rpm, Ne> N ₁₁ is not established and the flow branches to NO to reach the operating condition commander U and a command is issued to hold the current governor lever position. If the medium load state (that is, the holding state) continues for a while and then becomes the unloaded state again (engine speed Ne = 1920 → 1
(Return to 950 rpm) At that point, the flow becomes the flow of (iv), and the light load determination unit T shows Ne = 1950 rpm.
> N ₁₁ = 1940 rpm and Ne> N ₁₁ are satisfied, the operation command becomes a low speed operation command of I from the holding state without delay, and the governor lever is driven again toward the low speed operation position. Here, some supplementary explanation will be given regarding the holding function. 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. (A) Ne> N ₁₁ (light load condition) ---> low speed operation command (b) N ₁₁ >Ne> N ₁₃ (intermediate condition between heavy and light load) ---> current position holding command, that is, the set rotation speed ( Although the load is not heavy enough to return to high speed, a certain amount of load is applied, so from the viewpoint of the operability of the hydraulic excavator, the current governor lever position is maintained instead of dropping it at low speed.

2. Relationship between load state and engine control method when a medium speed operation command is issued 1) Load state and engine control method when a heavy load state changes to a medium load state

[Table 2]

(I) Heavy load condition 1. -1) Similar to the flow of (i), actual rotation Ne =
Make a heavy load at around 1800 rpm. 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 = 2000 rpm ・ Ne = 1800 rpm ・ Na = A _CCEL = 2000 rpm ・ 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 ・ N ₁₁ = 0 seconds ・ N ₁₂ = 0 seconds

(Ii) Medium load transition state (from when the load of the engine becomes small to immediately before the engine speed is reduced) Here, it is assumed that the load state changes from heavy load to medium load. As the medium load, a load of Ne = 1970 rpm is assumed. Engine speed Ne is 1800r
pm → 1970 rpm. Flow is A → B
→ C → D. Since the governor lever position is still set, in A, Na = A _CCEL = 2000 rpm
Has become. Therefore, even in D, N ₁₁ N ₁₂
The respective values of N ₁₃ N ₁₄ do not change and the flow value of (i) is maintained. Even in E, since it is in the set operation state, branch to YES as in the previous flow. The flow changes at the light load determination device F. That is, Ne = 1970 rpm <N ₁₁ = 19
Since it is 90 rpm, Ne> N ₁₁ is not established. N
Branch to O 2. Light load elapsed time measurement counter J
Then, the previous value is T ₁₁ = 0, but the clear operation is performed. Medium load judging device K: Ne = 1970 rp
Since m> N ₁₂ = 1950 rpm, the flow branches to YES. At L 2, the medium load elapsed time measuring counter is incremented and T ₁₂ becomes 0 → 0.02 seconds.
For the medium load elapsed time determination device M, T ₁₂ = 0.02 seconds <
Since T _1B = 10 seconds, T ₁₂ > T _1B is not established and after branching to NO, it reaches P, and the set rotation (accelerator instruction) operation is still commanded, and AEC still does not operate.

(Iii) Medium speed operation command start in medium load condition (when engine load exceeds a certain limit for a short time and engine speed starts to decrease) The flow of (ii) above is continued for 501 cycles. When it occurs, the medium speed operation command is started. In this flow, A → B → C →
The flow from D to E to F to J to K is performed in the same manner as the flow of (ii) above, and at 501 cycles, the medium load elapsed time measuring counter of L is counted up to T ₁₂ = 10.02 seconds. In the medium load elapsed time determining device M, T ₁₂ = 10.
02 seconds> T _1B = 10 seconds and T ₁₂ > T _1B holds.
It branches to YES and the middle speed operation is commanded for the first time at N. (Note that the elapsed time of light load is cleared to zero, so T ₁₁ = 0 seconds.)

(Iv) Moving to a low speed operation position under a medium load condition (process in which engine speed is lowered) Here, in response to the first middle speed operation command issued in the previous flow (iii), the governor lever The state where the governor lever is moving to the medium speed by the drive device is shown. As a specific example, the flow from the time when the governor lever is driven to the intermediate position of set to medium speed is shown. First, in A, unlike the above (iii), the value of Na changes because the governor lever is moved. For convenience of explanation, governor lever position and Na
_Assuming that 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: Actually, the governor and engine characteristics do not necessarily have a linear relationship, so the unloaded speed Na is calculated by a function stored in advance.) Engine speed Ne = 1
It is supposed to be 920 rpm. After Na is updated in this way, the flow is B → C → D, and each value is determined by the load judgment rotation speed setting unit D. ・ N ₁₁ = Na-10 rpm = 1950 rpm-10 rp
_{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 like m = 1880 rpm. At present, since the medium speed operation command is being issued, the operation status determiner E is NO, and the next Q is NO.
Branch to. Heavy load judgment device V: Ne = 1920
Since rpm> N ₁₄ = 1880 rpm, Ne <N ₁₄ is not satisfied, and NO is obtained. Since the operating condition determination unit W is moving to the medium speed, YES is determined. Furthermore, in the medium load determination device X, Ne = 1920 rpm> N ₁₂ = 19
It becomes 00 rpm and Ne> N ₁₂ is satisfied, and it branches to YES. At N, the medium speed operation (move to the medium speed position) command is continued.

(V) Medium-load state Medium-speed operation (when the engine maintains a desired range of medium-speed operation rotational speed) A flow when the governor lever finally reaches the medium-speed operation position is shown. However, Ne = 1870 rpm.
In this operating state, Na in A has the following values. Na = N _M1 = A _CCEL -100 rpm = 2000 rp
m-100 rpm = 1900 rpm, that is, Na becomes a medium speed operation rotation speed, and flows from B → C → D, and each value is set by the load determination rotation speed setting device D. ・ N ₁₁ = Na-10 rpm = 1900 rpm-10 rp
_{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 being issued, the operating status determiner E is NO, and the next Q is NO.
Branch to. Heavy load judgment device V: Ne = 1870
Since rpm> N ₁₄ = 1830 rpm, Ne <N ₁₄ is not established and the flow branches to NO. Since the operating condition determiner W has reached the medium speed, it becomes NO and branches directly to N. In this way, the medium speed operation is maintained in the medium load state.

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

(V) Medium-load medium-speed operation (when fuel is added to the engine for medium-speed operation at an almost desired medium-speed revolution) Here, the above-mentioned medium-load medium-speed operation state continues. It is assumed that The flow is 2. -1)-(v) is exactly the same. The constants and variables are 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 rp
_{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 seconds ・ N ₁₂ = 0.00 seconds

(Vi) Applying a heavy load (when a heavy load is applied to the engine during medium-speed operation) During the previous flow (v) (during medium-load medium-speed operation), the engine speed Ne = 1750 rpm Suppose a heavy load has entered. When this load is applied, the governor lever is still in the medium speed operation position. Therefore, in A, it becomes as follows.・ AEC SW = I stage ・ A _CCEL = 2000 rpm ・ Ne = 1750 rpm ・ Na = N _M1 = 1900 rpm The flow continues from B → C → D and the previous value is held at D. _{· N 11 = Na- 1rpm = 1900rpm-} 1rp
_{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 Currently, the medium speed operation command is being issued. The operation status determiner E turns to NO, and the next Q also turns to NO and branches to V. Heavy load determination device V: Ne = 1750 rp
m <N ₁₄ = 1830 rpm and true (Ne <N ₁₄ )
Holds and branches to YES. If it is judged to be a heavy load, P will be reached without delay and an immediate setting operation will be commanded. After the set rotation operation command, the flow is the same as the above-mentioned flow (i) under heavy load. However, both Ne and Na are updated every time before the governor lever returns to the set rotation position. N ₁₁ , N ₁₂ , N ₁₃ , and N ₁₄ are updated one by one according to the update of Na, and the load judgment conditions of F and K are updated. Also, the light / medium load elapsed time T ₁₁ , T ₁₂
At the time of the first passage through J and O, the value held last time is cleared to zero as follows, and when it is in a light or medium load state, it is possible to start counting up from zero seconds.・ T ₁₁ = 10.02 seconds → 0 seconds ・ T ₁₂ = 0.00 seconds → 0 seconds

3) Increase in load (holding operation) during movement of the medium speed operating position (engine load is small and medium load state continues and engine speed is reduced to medium speed, while load larger than medium load is applied. FLOW (iv) Start → A → B → C → D → E → Q → V → W
→ X → N → Begin (vii) Begin → A → B → C → D → E → Q → V → W → X → U
→ start

(Iv) Medium load state Medium speed operation position moving (as an example of the engine speed being lowered to medium speed, the engine speed is between the set speed and the medium speed operation command value). In some cases) Here, the above-mentioned flow 2. -1) -Flows in exactly the same way as (iv). That is, it is assumed that the governor lever is also in the intermediate position between setting and low speed. Therefore Ne = 1
920 rpm Na = 1950 rpm.
The values in D are also the same. _{· N 11 = Na-10rpm =} 1950rpm-10rp
_{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 the engine speed is being reduced to medium speed and a load larger than medium load but smaller than heavy load is applied) Previous flow (iv) (during medium speed movement ) The engine speed is N ₁₃
It is assumed that a load such that>Ne> N ₁₄ is entered. The engine speed is, for example, Ne = 1890 rpm. Input processing unit A has the following values.・ AEC SW = I stage ・ A _CCEL = 2000 rpm ・ Ne = 1890 rpm ・ Na = = 1950 rpm The flow continues from B → C → D → and the previous value (iv) is retained at D. At present, since the medium speed operation command is being issued, the operation status determiner E turns to NO, and the next Q also turns to NO and branches to V. Heavy load determination device V: Ne = 1890 rpm> N ₁₄ = 1880
It becomes rpm and true (Ne <N ₁₄ ) is not established, and it branches to NO. Since the operating condition determiner W is moving at a medium speed, the process branches to YES. Furthermore, medium load judgment device
In X, Ne = 1890 rpm <N ₁₃ = 1900 rp
Since it is m, Ne> N ₁₂ is not satisfied and the flow branches to NO to reach the operating condition command unit U and a command is issued to hold the current governor lever position. If the load state (that is, the holding state) continues for a while and then the medium load state is resumed (engine speed Ne = 1890 → 192
(Returns to 0 rpm) At that point, the flow is the flow of (iv), and the medium load determination device X shows Ne = 1920 rpm> N.
₁₂ = 1900 rpm and Ne> N ₁₂ holds,
The operation command becomes N medium speed operation command without delay from the holding state, and the governor lever is driven again toward the medium speed operation position. Here, some supplementary explanation will be given regarding the holding function. 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 (heavy / medium load intermediate state) ---> current position holding command, that is, the set rotation speed Although it is not a heavy load to return to (high speed), a certain amount of load is applied, so from the viewpoint of the operability of the hydraulic excavator, rather than dropping it to medium speed as it is, it is necessary to maintain the current governor lever position. To do. The amount of fuel supply is changed by changing the position of the governor lever. Generally, even if the position of the governor lever is held, the amount of fuel supply changes depending on the load. Instead of holding the current governor lever position, the governor lever may be operated to hold the fuel supply amount at that time.

As an example of the no-load (neutral) state determination 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, the portions designated by letters correspond to the flow chart portions of FIGS. Generally, during actual work such as excavation in a hydraulic excavator, the engine speed also changes according to the load change. On the other hand, in the no-load (neutral) state, the engine speed is stably set to a constant value except for the overshoot period immediately after the load is removed. Therefore, measuring the variation of the engine speed can be a condition for determining the no-load condition. That is, as described below, the low speed operation is commanded by taking the logical product of the variation value of the engine speed (stability determination result), the neutral detection pressure switch signal and the light load progress determination result. In addition, even if a pressure switch failure (disconnection, etc.) occurs during the load, this method prevents the engine speed from becoming stable due to load fluctuations, and prevents inadvertent issuance of a low-speed operation command and does not hinder operability. There is another advantage to say.

1. Flow when selecting AEC I stage 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, in the signal input processing unit A, the pressure switch signal is turned ON.
(During load) or OFF (no load) is input.
Also, the pressure switch signal determination unit a is ON because it is a heavy load, and differs in that it bypasses b and branches to F. By bypassing b (that is, during loading), N ₁₁ maintains the value set by the governor lever position signal at D, and is used in the subsequent light load determination unit F, which is the same as that described above. .

(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 B → C → D → E → a. Since the pressure switch signal is OFF at the part a, 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 determination unit F, the above N ₁₁
Ne> N ₁₁ is always satisfied by rewriting, and the process branches to YES. The counter G c counts up respectively, and the light load elapsed time and the rotational speed stable measurement time are T ₁₁ = 0.02 seconds and T ₁₃ = 0.02 seconds. At d, the stable measurement start time has not yet been reached. That is, T ₁₃ =
0.02 seconds ≠ T _1STRT = 1.8 seconds NO
Then branch to f. Even at f, T _1STRT =
1.8 seconds> T ₁₃ = 0.02 seconds and the truth is not established. H
Branch to. Because T ₁₁ = 0.02 seconds <T _1A = 3 seconds
It branches to K, and because it is a light load, it branches to L, and it counts up to T ₁₂ = 0.02 seconds at L, but M
Then, T ₁₂ = 0.02 seconds <T _1B = 10 seconds, and the true is not established, and the set rotation command is still maintained at P.

(Iii) Maintaining no-load state (T ₁₃ = T _1STRT ) This flow describes the state 1.8 seconds (= T ₁₃ = T _1STRT ) after the load is _removed in the no-load setting operation command state. To do. The flow is A → B → C → D → E → a → b → F → G
And flow G and c at T ₁₁ = 1.8 seconds, T ₁₃
= 1.8 seconds. Rotation speed stable measurement start time judgment device
In c, T ₁₃ = T _1STRT = 1.8 seconds, so Y
It 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, and the flow branches to H, and then the flow setting rotation command is maintained as H → K → L → M → P.

(Iv) Maintaining no-load state-stable measurement time period (T
_1FNSH > T ₁₃ > T _1STRT ) In this flow, the fluctuation value of the rotation speed is calculated and the maximum value and the minimum value are updated. Currently
T ₁₁ = T ₁₂ = T ₁₃ = 2.4 seconds. The flow is A →
B → C → D → E → a → b → F → G → c → d, then d
Then, since T ₁₃ = 2.4 seconds ≠ T _1STRT = 1.8 seconds, it becomes NO (that is, the measurement reference 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 calculated and compared with the maximum and minimum fluctuations in the past during the main measurement period. 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 to L → M → P.

(V) Maintaining no-load state-after elapse of stable measurement time (T _1A > T ₁₁ = T ₁₃ > T _1FNSH ) The situation before the rotational speed stable measurement time has passed but before the light load allowable elapsed time is 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 and the flow f
And the rotation speed fluctuation is no longer calculated. At H, since the light load allowable elapsed time (T _1A ) is before, K → L → M →
It becomes P and remains at the set rotation.

(Vi) No-load state maintenance-after light load allowable elapsed time (T ₁₁ = T ₁₃ > T _1A ) This flow describes the 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, and T ₁₁ = 3.
02 seconds> T _1A = 3 seconds, so YES. H
Branch to. In h, the maximum / minimum fluctuation values (M _AX1 , M _IN1 ) sorted by the previous rotation speed fluctuation value calculation unit
Is used to calculate the maximum speed variation range N _DIFF .
Next, the rotation speed stability determiner i makes a stability determination.
If the rotation speed fluctuation maximum width N _DIFF is smaller than the judgment reference value N _STAB , it is regarded as a stable state and the low speed operation command of I is reached. If N _DIFF <N _STAB does not hold, it is considered that a load is present and the process branches to j.
Light load elapsed time and rotation speed stable measurement time counter
T ₁₁ T ₁₃ or maximum / minimum value of rotational speed fluctuation 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
Return to i) and repeat the stability judgment.

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

In the present invention, instead of or in combination with reducing the supply of fuel to the engine and reducing the engine speed when the engine load is less than the first predetermined value (the following conditions and logic are The pressure gauge indicates that the commands to stop all the hydraulic actuators have been input to the hydraulic valves 3 and 4 that are arranged between the hydraulic pump and the hydraulic actuator and that control the operation and stop of the hydraulic actuator. Detected from the output of 11,
The command has been held for a predetermined time (which is the same as the time when the engine speed is lower than the first predetermined value, which is the condition for reducing the engine speed based on the load condition of the engine). 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 theoretical product or a logical sum, when the time when the fluctuation range of the engine load is less than the predetermined range continues for a predetermined time or longer, the fuel supply to the engine is reduced to reduce the engine speed. May be reduced. Also, after the engine speed has been reduced in this way, 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 in combination with them. The fuel supply to the engine may be increased and the engine speed may be increased when a command to operate at least one hydraulic actuator is issued. The engine load may be measured from the actual output torque of the engine. The engine load may be measured from the output flow rate from the hydraulic pump. When the fuel supply reduction prohibition command is further input and there is the fuel supply reduction prohibition command, even if 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 fuel supply to the engine does not have to be reduced.

[Brief description of 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 an embodiment of a method for controlling a hydraulic pump drive engine according to the present invention.

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

FIG. 4 is a diagram showing a part of a flowchart of an embodiment of a method for controlling a hydraulic pump drive engine according to the present invention.

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

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

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

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

[Explanation 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 device 9 Control device 10 Rotation speed detector 11 Pressure gauge 11 12 Accelerator setter 13 AEC setting device 14 Governor lever position detector

Claims (21)

[Claims] 1. A method of controlling an actuator hydraulic power source pump drive engine for construction machinery, wherein the load of the engine driving a hydraulic pump that generates hydraulic pressure for driving a hydraulic actuator is less than a first predetermined value. The step of reducing the supply of fuel to the engine to reduce the engine speed, and after the engine speed is reduced by the load of the engine for driving the hydraulic pump being less than a predetermined value, And a step of increasing the supply of fuel to the engine to increase the number of revolutions of the engine when the load of the engine for driving the hydraulic pump exceeds a second predetermined value. Control method. 2. A method for controlling a hydraulic pump for driving a hydraulic power source for an actuator for a construction machine, wherein all hydraulic actuators are stopped by a hydraulic valve that controls operation and stop of a hydraulic actuator arranged between the hydraulic pump and the hydraulic actuator. When a command is input and the command is held for a predetermined time or longer, a step of reducing the supply of fuel to the engine to reduce the engine speed, and a command to stop all hydraulic actuators in the hydraulic valve are input. When the load of the engine for driving the hydraulic pump becomes a second predetermined value or more after the engine speed is reduced by holding the command for a predetermined time or more, Increasing the supply and increasing the engine speed, the method of controlling a hydraulic pump driven engine. 3. The hydraulic pump drive engine control method according to claim 1, wherein the load of the engine that drives the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. A method for controlling a hydraulic pump driven engine, wherein when the time exceeds a predetermined amount, the supply of fuel to the engine is reduced and the engine speed is reduced. 4. The method for controlling a hydraulic pump drive engine according to claim 1, wherein the load of 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 whether or not the engine load is
When the amount of fuel supplied at the time of judgment is supplied when the hydraulic actuator is not operating, the first rotation speed at which the engine rotates at a higher rotation speed and the load that operates the hydraulic actuator A control method, which is measured from a difference from an actual engine speed that is lower than a first engine speed, and determines that the engine load is less than a first predetermined value when the difference is smaller than a predetermined degree. 5. The method for controlling a hydraulic pump drive engine according to claim 1, wherein the load of the engine that drives the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. The load of the engine when determining whether or not it is measured from the actual output torque of the engine, and when the actual output torque of the engine is smaller than a predetermined degree, the engine load is less than the first predetermined value. The control method to judge. 6. The method for controlling a hydraulic pump drive engine according to claim 1, wherein the load of the engine that drives the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. The load of the engine when determining whether or not it is measured from the output flow rate from the hydraulic pump, and when the output flow rate from the hydraulic pump is smaller than a predetermined degree, the engine load is less than the first predetermined value. The control method to judge. 7. A method for controlling a hydraulic pump drive engine according to claim 1, wherein the load of the engine that drives a hydraulic pump that generates a hydraulic pressure for driving a hydraulic actuator is the first load. One is less than a predetermined value, or a command to stop all the hydraulic actuators is input to the hydraulic valve and the command is held for a predetermined time or more, so that the fuel supply to the engine is a predetermined amount. The engine load for determining whether or not the engine load for driving the hydraulic pump is equal to or greater than a second predetermined value after the engine speed is reduced to When the predetermined amount of fuel is supplied to the engine that drives the hydraulic pump when not in operation, it is the speed at which the engine rotates at a higher speed than the second speed. Measured from the difference between the number of revolutions and the actual number of revolutions of the engine that is lower than the second number of revolutions due to the load that operates the hydraulic actuator, and when the difference is greater than a prescribed amount, the engine load is the second prescribed value. A control method for determining that the above is the case. 8. A method for controlling a hydraulic pump drive engine according to claim 1, wherein the load of the engine for driving the hydraulic pump exceeds a second predetermined value. The load of the engine when determining whether or not is measured from the actual output torque of the engine, and when the actual output torque of the engine is larger than a predetermined degree, it is determined that the load of the engine is equal to or more than the second predetermined value. To do
Control method. 9. The control method for a hydraulic pump drive engine according to claim 1, wherein the load of the engine for driving the hydraulic pump exceeds a second predetermined value. The load of the engine when determining whether or not is measured from the output flow rate from the hydraulic pump, and when the output flow rate from the hydraulic pump is larger than a predetermined level, it is determined that the engine load is equal to or higher than the second predetermined value. Control method. 10. The method for controlling a hydraulic pump driving engine according to claim 1, wherein the load of the engine driving the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. Also, when a command to stop all the hydraulic actuators is input to the hydraulic valve that is placed between the hydraulic pump and the hydraulic actuator and that controls the operation and stop of the hydraulic actuator, the fuel supply to the engine is reduced and the engine rotation is reduced. A control method that reduces the number. 11. A method for controlling a hydraulic pump drive engine according to claim 1, wherein the load of the engine that drives the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is first. Is less than the predetermined value of, and a command to stop all the hydraulic actuators is input to the hydraulic valve that is arranged between the hydraulic pump and the hydraulic actuator and that controls the operation and stop of the hydraulic actuator, and the command is for a predetermined time or more. A control method that reduces the supply of fuel to the engine and reduces the engine speed when held. 12. A method for controlling a hydraulic pump drive engine according to claim 1, wherein the load for driving the hydraulic pump is less than a predetermined value, or the hydraulic pressure is less than a predetermined value. A command to stop all hydraulic actuators was input to the valve and the command was held for a predetermined time or longer, so that the load for driving the hydraulic pump is reduced to the second predetermined value after the engine speed is reduced. Is greater than or equal to the value of and the command to operate at least one of the hydraulic actuators is input to the hydraulic valve that is placed between the hydraulic pump and the hydraulic actuator and that controls the operation and stop of the hydraulic actuator. Increase fuel supply and increase engine speed,
Control method. 13. A control method for a hydraulic pump drive engine according to claim 1, wherein the load for driving the hydraulic pump is less than a predetermined value, or the hydraulic valve. When a command to stop all the hydraulic actuators is input to and the command is held for a predetermined time or longer, at the stage of reducing the fuel supply to the engine and reducing the engine speed, the fuel supply to the engine is Gradually reduce, while gradually reducing the supply of fuel to the engine, the load for driving the hydraulic pump is equal to or more than the predetermined value, but is less than the second predetermined value, A control method that stops reducing the supply of fuel to the engine. 14. A method for controlling a hydraulic pump drive engine according to claim 1, wherein it is determined whether or not there is a fuel supply reduction prohibition command, and when there is a fuel supply reduction prohibition command. Means that even if the load of the engine that drives the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuators is less than a first predetermined value, or if a command to stop all the hydraulic actuators is input to the hydraulic valve and the command is A control method in which the supply of fuel to the engine is not reduced even if it is held for a predetermined time or longer. 15. A method for controlling a hydraulic pump drive engine according to claim 1, wherein all hydraulic actuators are stopped by a hydraulic valve that is arranged between the hydraulic pump and the hydraulic actuator and that controls the operation and stop of the hydraulic actuator. A control method for reducing the supply of fuel to the engine and reducing the engine speed even when a command is input and the command is held for a predetermined time or more. 16. The method for controlling a hydraulic pump drive engine according to claim 1, wherein the engine speed is reduced after the load for driving the hydraulic pump is less than a predetermined value, and then the hydraulic pressure is reduced. When a command to operate at least one of the hydraulic actuators is input to the hydraulic valve that is placed between the pump and the hydraulic actuator and that controls the operation and stop of the hydraulic actuator, the fuel supply to the engine is increased and the engine is increased. Control method to increase the rotation speed of the. 17. The method for controlling a hydraulic pump driving engine according to claim 1, wherein the load of the engine driving the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. And, when the time period in which the load variation range is less than a predetermined range continues for a predetermined time or more, the supply of fuel to the engine is reduced and the engine speed is reduced.
Control method. 18. A method for controlling a hydraulic pump drive engine according to claim 2, wherein all hydraulic actuators are stopped by hydraulic valves that are arranged between the hydraulic pump and the hydraulic actuator and that control the operation and stop of the hydraulic actuator. When a command is input, the command is held for a predetermined time or longer, and the load fluctuation range is less than the predetermined range for a predetermined time or longer, the fuel supply to the engine is reduced and the engine speed is reduced. Control method to reduce the. 19. The control method for a hydraulic pump drive engine according to claim 2, wherein all hydraulic actuators are stopped by a hydraulic valve that controls operation and stop of a hydraulic actuator arranged between the hydraulic pump and the hydraulic actuator. The fact that the command to input is input is a control method that is detected from the position of the operation member for the driver to operate the hydraulic valve. 20. The method for controlling a hydraulic pump drive engine according to claim 3, wherein the load of the engine that drives the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. A hydraulic pump that reduces the supply of fuel to the engine and decreases the rotational speed of the engine when the time exceeds a predetermined amount and the load fluctuation range is less than the predetermined range for a predetermined time or more. Driving engine control method. 21. The method for controlling a hydraulic pump drive engine according to claim 11, wherein the load of the engine driving the hydraulic pump that generates the hydraulic pressure for driving the hydraulic actuator is less than a first predetermined value. A command for stopping all the hydraulic actuators is input to a hydraulic valve that is arranged between the hydraulic pump and the hydraulic actuator and that controls the operation and stop of the hydraulic actuator, and the command is held for a predetermined time or more, and the load The control method of reducing the supply of fuel to the engine and decreasing the engine speed when the time period in which the fluctuation range is less than the predetermined range continues for a predetermined time or more.