JP2009281149A - Engine control device and working machine equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine control device capable of preventing deterioration in responsiveness even if a target flow rate is abruptly increased, and to provide a working machine equipped with the engine control device. <P>SOLUTION: The engine control device includes a rotation speed setting means for setting a target rotation speed of an engine 5 based on a flow rate of hydraulic oil required by an actuator, and an operating state determination means for determining whether or not the operating state is in a rapid load operating period in which the hydraulic oil flow rate required by the actuator may be abruptly increased. The rotation speed setting means sets a normal target rotation speed when it is determined that the operating state is not in the rapid load operating period, and sets a rapid load target rotation speed higher than the normal target rotation speed when it is determined that the operating state is in the rapid load operating period. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine control device that controls an engine for driving a hydraulic pump.

  2. Description of the Related Art Conventionally, a working machine including a variable displacement hydraulic pump driven by an engine and an actuator driven by hydraulic oil supplied from the hydraulic pump is known.

  In this type of work machine, one having an engine control device that controls the number of revolutions of the engine according to the power required for the actuator is known (for example, Patent Document 1).

The engine control device disclosed in Patent Document 1 uses an engine speed (hereinafter referred to as a first speed) for discharging the target flow rate of the hydraulic pump calculated according to the operation amount of the operation lever at the maximum tilt of the hydraulic pump. ) And the engine speed (hereinafter referred to as the second speed) at which the required horsepower of the hydraulic pump required to discharge the target flow rate is obtained and the fuel consumption rate is the lowest. The larger one of the first and second rotational speeds is selected.
JP-A-11-2144

  By the way, in order to increase the discharge amount of the hydraulic pump, it is conceivable to increase the tilt of the hydraulic pump or increase the engine speed, but in order to increase the engine speed, the tilt is increased. Since it takes a longer time than when increasing the flow rate, it is desirable to adjust the tilt of the hydraulic pump in order to improve the responsiveness with respect to the increase in the discharge amount.

  In the engine control device of Patent Document 1, when the first rotation speed is selected, the tilt of the hydraulic pump can be maximized by reducing the engine rotation speed to improve fuel consumption. Since the rotation cannot be further increased, the engine speed has to be increased in order to secure the flow rate, and there is a problem that the responsiveness for obtaining the target flow rate deteriorates.

  On the other hand, even when the second rotational speed is selected, when the tilt of the hydraulic pump set corresponding to the engine speed selected in this way is close to the maximum tilt, the target flow rate is thereafter increased. There has been a problem that the responsiveness for obtaining the target flow rate is deteriorated in the same manner as described above when the value increases rapidly.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an engine control device that can suppress deterioration of responsiveness even when the target flow rate is rapidly increased, and a work machine including the same. It is said.

  In order to solve the above problems, the present invention is required for an engine, a variable displacement hydraulic pump driven by the engine, an actuator driven by hydraulic fluid supplied from the hydraulic pump, and the actuator. And an adjusting means for adjusting the tilt of the hydraulic pump for discharging the hydraulic oil flow rate according to the engine speed, and based on the hydraulic oil flow rate required for the actuator An engine control device for controlling the engine speed, the engine speed setting means for setting a target engine speed based on a hydraulic oil flow rate required for the actuator, and a target set by the speed setting means Rotational speed adjusting means for adjusting the rotational speed of the engine based on the rotational speed, and hydraulic fluid flow required for the actuator Working state determining means for determining whether or not the engine is in a period of sudden load work in which there is a possibility of sudden increase, and the rotation speed setting means is provided during the sudden load work period by the working state determination means. When it is determined that there is not, the normal target rotational speed is set, while when it is determined by the working state determination means that it is during the sudden load work period, the sudden rotational speed is higher than the normal target rotational speed An engine control device characterized by setting a target rotational speed is provided.

  According to the present invention, the target rotational speed at the time of a sudden load that is set when it is determined that the hydraulic fluid flow rate required for the actuator is in a sudden load work period in which there is a possibility of abrupt increase is the sudden load work period. Since the rotation speed is set to be equal to or higher than the normal rotation speed determined not to be inside, the tilt of the hydraulic pump can be kept smaller than that in the normal operation.

  Therefore, according to the present invention, when the engine speed is set as high as possible during the sudden load work period and the tilt of the hydraulic pump is kept small by that amount, the target flow rate increases rapidly thereafter. Can be dealt with quickly by increasing the pump tilt.

  Therefore, according to the present invention, deterioration of responsiveness can be suppressed even when the target flow rate increases rapidly.

  In order to determine whether or not it is during the sudden load period, the work state determination means includes a storage unit that stores a change in the discharge flow rate of the hydraulic pump during a first elapsed period from the present time to a first time before The first maximum change flow rate obtained by subtracting the minimum value from the maximum value of the discharge flow rate in the first elapsed period and the maximum value of the discharge flow rate in the second elapsed period from the current time to the second time shorter than the first time. A difference calculation unit that calculates a second maximum change flow rate obtained by subtracting the minimum value, and comparing the first maximum change flow rate and the second maximum change flow rate to determine whether or not it is during a period of heavy load work. It can be set as the structure provided with the determination part to perform.

  In this way, the first maximum change flow rate during the past first elapsed period and the second maximum change flow rate during the latest second elapsed period that is shorter than the first elapsed period are used. For example, when the most recent second maximum change flow rate is increased to a predetermined ratio of the first maximum change flow rate, it can be determined that the sudden load period is in effect.

  In addition, in order to determine whether or not it is during the sudden load period, the work state determination means stores a transition of the power of the hydraulic pump in a first elapsed period from the present time to a first time before And the first maximum change power obtained by subtracting the minimum value from the maximum value of the power of the hydraulic pump in the first elapsed period and the hydraulic pump in the second elapsed period from the present time to the second time shorter than the first time. A difference calculation unit that calculates a second maximum change power obtained by subtracting a minimum value from the maximum value of the power of the power, and comparing the first maximum change power and the second maximum change power during the period of the sudden load work It can also be set as the structure provided with the determination part which determines whether there exists.

  Even when configured in this way, similarly to the above-described configuration, for example, the most recent second maximum change power is a predetermined value of the first maximum change power using the first maximum change power and the second maximum change power. It can be determined that there is a sudden load work period when the ratio increases to a rate.

  On the other hand, in order to set the target rotational speed at the time of sudden load, the rotational speed setting means is assumed to be necessary after a specific time has elapsed from the present time when it is determined that it is during the sudden load work period. Means for specifying the assumed engine speed of the engine, and an increase rate of the engine speed when the target engine speed at the time of sudden load increases to the assumed engine speed during the specified time, the sudden load work period Means for specifying an allowable increase rate allowed therein, and means for specifying an ideal rotation number that will increase to the assumed rotation number when the specified time has elapsed according to the allowable increase rate, It can be set as the structure which sets the rotation speed more than an ideal rotation speed to the said target rotation speed at the time of a sudden load.

  In this way, when it is assumed that the engine speed is increased up to the assumed engine speed that is assumed to be required during the sudden load period, the increase rate of the engine speed is allowed during the sudden load period. Since it is possible to set the number of revolutions equal to or higher than the ideal number of revolutions specified so as to be an allowable increase rate to be the target speed at the time of sudden load, the above assumption is made based on the target speed at the time of sudden load thus set. The rate of increase in the number of rotations up to the number of rotations can be kept below the allowable increase rate.

  Therefore, according to this configuration, since it is possible to avoid a sudden increase in the number of rotations even when the increase in the number of rotations up to the assumed number of rotations is required thereafter, the responsiveness is further deteriorated. It can be surely suppressed.

  Specifically, the rotational speed setting means includes a storage unit that stores a transition of the discharge flow rate of the hydraulic pump and a transition of the engine rotational speed during a first elapsed period from the current time to a first time, and the first elapsed period. An increase rate calculation unit that calculates an average value of an increase rate of the engine speed per unit time of the engine speed as the allowable increase rate, and when the second time shorter than the first time has elapsed, the increase in the engine speed A first rotation in which the maximum value of the discharge flow rate in the first elapsed period is calculated as the first ideal rotation speed at which the hydraulic pump can discharge at the maximum tilt according to the engine rotation speed rising according to the rate average value It can be set as the structure provided with the number calculating part.

  In this way, even if the maximum flow rate generated during the past first time becomes the target flow rate after the second time shorter than the first time, the target flow rate is set to the average value of the rotational speed increase rate. The current rotational speed (first ideal rotational speed) at which the hydraulic pump can discharge at the maximum tilt can be calculated from the engine rotational speed increased according to the engine rotational speed. Even if it is necessary to discharge the maximum flow rate after the elapse of the second time, the engine rotation speed increase rate is less than the average rotation speed increase rate in the past first elapsed period. Can be suppressed.

  More specifically, the first rotation speed calculation unit includes an expected increase rotation speed when the second time has elapsed, a maximum value of the discharge flow rate during the first elapsed period, and a maximum tilt of the hydraulic pump. The first ideal rotational speed can be calculated based on the above.

  Further, the rotation speed setting means stores a transition of the power of the hydraulic pump during the first elapsed period, and the increase rate calculating unit is configured to generate a discharge pressure per unit time of the hydraulic pump during the first elapsed period. The average value of the discharge pressure increase rate is calculated, and the first rotation speed calculation unit increases the discharge pressure and the rotation speed increase rate average value according to the discharge pressure increase rate average value when the second time has elapsed. A maximum engine power value in the first elapsed period is calculated as a second ideal engine speed at which the hydraulic pump can output at a maximum tilt. It is preferable to set a rotation speed greater than the ideal rotation speed and the second ideal rotation speed as the target rotation speed at the time of sudden load.

  In this way, at least a larger ideal rotational speed among the first ideal rotational speed calculated assuming the future target flow rate and the second ideal rotational speed calculated assuming the power of the future hydraulic pump. Since the above rotation speed can be set as the target rotation speed at the time of sudden load, the increase rate of the engine rotation speed for ensuring these can be kept as small as possible while ensuring the target flow rate and power in the future. Thus, it is possible to suppress deterioration of responsiveness.

  Further, in order to calculate the ideal rotation speed, the rotation speed setting means includes a change in the discharge flow rate of the hydraulic pump, a change in power, and a change in engine speed during a first elapsed period from the present time to the first hour before. And an average value of the engine speed increase rate per unit time in the first elapsed period as the permissible increase rate and a unit of discharge pressure of the hydraulic pump in the first elapsed period An increase rate calculation unit that calculates an average value of the increase rate of discharge pressure per hour, an engine speed that increases according to the average value of the speed increase rate when a second time shorter than the first time has elapsed, and the The current value at which the hydraulic pump can output the maximum value of the power of the hydraulic pump in the first elapsed period with the maximum tilt by the discharge pressure increasing according to the average value of the increase rate of the discharge pressure The rotational speed can also be configured such that a first rotation speed calculation unit that calculates, as the ideal rotation speed.

  In this way, even if the maximum power generated during the past first time becomes the target power after the elapse of the second time shorter than the first time, this target power is averaged at the rate of increase in the rotational speed. Since the engine speed increased according to the value and the discharge pressure increased according to the discharge pressure increase rate average value, the current speed (ideal speed) at which the hydraulic pump can output at the maximum tilt can be calculated. By setting the rotation speed equal to or higher than the ideal rotation speed as the target rotation speed at the present time, even if it is necessary to output the maximum power after the elapse of the second time, the rate of increase in the engine rotation speed is the first in the past. The rotation speed increase rate during the elapsed period can be kept below the average value.

  Specifically, the apparatus further includes detection means for detecting a discharge pressure of the hydraulic pump, and the first rotation speed calculation unit includes an expected increase rotation speed and an expected increase discharge pressure when the second time has elapsed, The ideal rotation speed can be calculated based on the discharge pressure of the hydraulic pump and the maximum tilt of the hydraulic pump.

  The engine speed setting means has a small fuel consumption engine speed with a low fuel consumption rate based on a preset map among engine engine speeds for causing the hydraulic pump to discharge the hydraulic oil flow rate required for the actuator. A second rotational speed calculation unit for specifying the engine speed, and when it is determined that the engine is in the sudden load work period, a larger one of the ideal rotational speed and the low fuel consumption rotational speed is set as the target rotational speed at the time of sudden load. On the other hand, when it is determined that it is not during the sudden load work period, it is preferable to set the low fuel consumption rotational speed to the normal target rotational speed.

  In this way, when it is determined that the engine is in the sudden load period, a larger one of the ideal rotation speed and the fuel efficiency rotation speed can be set as the target rotation speed at the time of sudden load. It can be suppressed from becoming larger than necessary, and deterioration of the fuel consumption rate can be suppressed.

  On the other hand, the rotational speed setting means calculates a second rotational speed calculation for calculating the maximum rotational speed of the engine at which the hydraulic pump can discharge the hydraulic oil flow required for the actuator at the maximum tilt. A large one of the ideal rotation speed and the maximum rotation speed is set as the sudden load target rotation speed when the sudden load work period is determined, When it is determined that it is not in the work period, the maximum rotation speed can be set to the normal target rotation speed.

  In this way, when it is determined that the vehicle is in a sudden load period, a larger one of the ideal rotation speed and the maximum rotation speed can be set as the target load speed during sudden load. It is possible to suppress the rotational speed from becoming larger than necessary, and to suppress the deterioration of the fuel consumption rate.

  Furthermore, the present invention discharges an engine, a variable displacement hydraulic pump driven by the engine, an actuator driven by hydraulic oil supplied from the hydraulic pump, and a hydraulic oil flow rate required for the actuator. There is provided a work machine including an adjusting means for adjusting a tilt of the hydraulic pump to be adjusted according to the engine speed and the engine control device.

  According to the present invention, the target rotational speed at the time of a sudden load that is set when it is determined that the hydraulic fluid flow rate required for the actuator is in a sudden load work period in which there is a possibility of abrupt increase is the sudden load work period. Since the rotation speed is set to be equal to or higher than the normal rotation speed determined not to be inside, the tilt of the hydraulic pump can be kept smaller than that in the normal operation.

  Therefore, according to the present invention, when the engine speed is set as high as possible during the sudden load work period and the tilt of the hydraulic pump is kept small by that amount, the target flow rate increases rapidly thereafter. Can be dealt with quickly by increasing the pump tilt.

  Therefore, according to the present invention, deterioration of responsiveness can be suppressed even when the target flow rate increases rapidly.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall view schematically showing an electrical configuration and a hydraulic system of a work machine according to an embodiment of the present invention.

  Referring to FIG. 1, for example, a working machine represented by a hydraulic excavator is omitted in illustration, but a hydraulic motor 2 for driving the upper swing body (an example of a drive target) to swing relative to the lower traveling body. In addition, an actuator including a hydraulic cylinder 3 and the like for raising and lowering a work attachment (an example of an object to be driven) provided on the upper swing body is provided. Hereinafter, a working machine including a hydraulic system including the hydraulic motor 2 and the hydraulic cylinder 3 as an example of an actuator will be described.

  The work machine includes a hydraulic circuit 4, an engine 5, a variable displacement hydraulic pump 6 driven by the engine 5, and the hydraulic motor 2 and hydraulic cylinder driven by hydraulic oil supplied from the hydraulic pump 6. 3, a pressure sensor 7 for detecting the hydraulic pressure discharged from the hydraulic pump 6, and a controller (engine control device) for controlling the rotational speed of the engine 5 based on the power required for the hydraulic motor 2 and the hydraulic cylinder 3. ) 8 and a first dial 14 and a second dial 15 connected to the controller 8.

  The hydraulic circuit 4 includes an oil passage through which hydraulic oil discharged from the hydraulic pump 6 can be supplied to the hydraulic motor 2 and the hydraulic cylinder 3, and hydraulic oil discharged from the hydraulic motor 2 and the hydraulic cylinder 3. A switching valve capable of appropriately switching between an oil path for recovery in the tank 25 is provided at an appropriate position. The hydraulic circuit 4 includes an operation lever 9 that receives an operator's input operation. The operation lever 9 outputs an electrical signal for driving the hydraulic motor 2 and the hydraulic cylinder 3 in accordance with the operator's input operation. To output.

  The engine 5 includes an engine main body 24, an engine control unit 10 and a rotation speed sensor 11 provided in the engine main body 24. The engine body 24 includes an output shaft 24a connected to the hydraulic pump 6 so that the hydraulic pump 6 can be rotationally driven. The engine control unit 10 adjusts the fuel injection amount in accordance with a control signal from the controller 8. The rotation speed sensor 11 is configured to be able to detect the rotation speed of the output shaft 24a.

  The hydraulic pump 6 is an axle type variable displacement pump and includes a regulator 12 for adjusting the tilt thereof. The regulator 12 is electrically connected to the controller 8.

  The controller 8 includes a CPU that executes various arithmetic processes, a ROM that stores initial settings, and a RAM that temporarily stores various information. The controller 8 is electrically connected to the operation lever 9, pressure sensor 7, first dial 14, second dial 15, rotation speed sensor 11, engine control unit 10, and regulator 12.

  FIG. 2 is a block diagram functionally showing the configuration of the controller.

  Referring to FIG. 2, the controller 8 includes a target flow rate calculation unit 16, a difference calculation unit 17, a storage unit 18, an increase rate calculation unit 19, a determination unit 20, a first rotation speed calculation unit 21, It functions as the second rotation speed calculation unit 22 and the drive control unit 23.

  As shown in FIGS. 7 and 8, the storage unit 18 includes a flow rate of the hydraulic pump 6 in the first elapsed period from the current time to T time (first time) and a rotational speed of the engine 5 in the first elapsed period. Is stored.

  The target flow rate calculation unit 16 is based on a signal input by the operation lever 9, an accelerator command signal input by the first dial 14, and a signal related to the discharge pressure of the hydraulic pump 6 input by the pressure sensor 7. The current target flow rate Qr is calculated. This target flow rate Qr is stored in the storage unit 18.

  Based on the information stored in the storage unit 18, the difference calculation unit 17 determines the minimum value of the flow rate in the first elapsed time from the maximum value Q (T) max of the flow rate in the first elapsed period from the current time to T hours before. The maximum change flow rate ΔQ (T) (first maximum change flow rate) at the first elapsed time obtained by subtracting Q (T) min (see FIG. 7) is calculated. Further, the difference calculation unit 17 calculates the minimum value of the flow rate in the second elapsed period from the maximum value Q (t) max of the second elapsed period from the present time to t time (second time) shorter than the T time. The maximum change flow rate ΔQ (t) (second maximum change flow rate) in the second elapsed period obtained by subtracting Q (t) min is calculated.

  The increase rate calculation unit 19 calculates an average value B of the increase rate per unit time of the engine speed in the first elapsed period. That is, the increase rate calculation unit 19 cuts out the sections b1 to b8 where the rotational speed is increasing from the transition of the engine rotational speed shown in FIG. 8, and based on the increased sections b1 to b8, the unit per unit time. A rotation speed increase rate average value B is calculated.

  The first rotation speed calculation unit 21 calculates an expected increase rotation speed ΔN (t) after elapse of time t based on the rotation speed increase rate average value B using the following formula (1).

ΔN (t) = B × t (1)
Further, the first rotational speed calculation unit 21 uses the relational expression (2) between the flow rate Q of the hydraulic pump 6, the tilt q of the hydraulic pump 6, and the engine rotational speed N, to maximize the flow rate during the first elapsed period. The relationship between the value Q (t) max, the maximum tilt qmax of the hydraulic pump 6, the expected increased rotational speed ΔN (t) after elapse of t time, and the rotational speed N1 to be the next target is expressed by the following formula (3 ), And using this equation (3), the rotational speed N1 is calculated as shown in the following equation (4).

Q = q × N (2)
Q (t) max = qmax × {N1 + ΔN (t)} (3)
N1 = {Q (t) max−qmax × ΔN (t)} (4)
From this equation (4), the ideal rotation speed N1 (first ideal rotation speed) at which the hydraulic pump 6 can discharge the maximum value Q (t) max of the flow rate in the first elapsed period with the maximum tilt qmax after elapse of t time. Can be calculated.

  The second rotational speed calculation unit 22 sets the engine speed N2 (hereinafter referred to as the maximum rotational speed N2) for the hydraulic pump 6 to discharge the target flow rate Qr at the maximum tilt qmax, using the following formula (5). Calculated by

N2 = Qr / qmax (5)
The maximum tilting rotation speed N2 may be set based on the rotation speed input by the first dial 14.

  The determination unit 20 multiplies the maximum change flow rate ΔQ (T) in the first elapsed period by the responsiveness coefficient A input by the second dial 15 and the maximum change flow rate ΔQ (t in the second elapsed period. ) With the following formula (6).

ΔQ (t) ≧ ΔQ (T) × A (6)
Then, the determination unit 20 determines that the flow rate required for the hydraulic pump 6 is suddenly increased when the expression (6) is satisfied, and determines that the expression (6) is satisfied. When it is not satisfied, it is determined that it is in a normal work period.

  Further, when the determination unit 20 determines that it is in the sudden load work period, the determination unit 20 compares the ideal rotation speed N1 with the maximum rotation speed N2, and sets the large rotation speed as the target rotation speed during the sudden load. adopt.

  The drive control unit 23 calculates the tilt of the hydraulic pump 6 and the fuel injection flow rate of the engine 5 based on the adopted target rotational speed, and outputs an electrical signal corresponding to these to the engine control unit 10 and the regulator 12. It is supposed to be.

  Hereinafter, processing executed by the controller 8 will be described with reference to FIG. FIG. 3 is a flowchart showing processing executed by the controller.

  When the process is started, first, the current work state determination process U is executed. If it is determined that the work state determination process U is in the sudden load work period, the rapid load rotation speed calculation process V is executed. The rotational speed calculation process O is executed.

  Then, based on the target rotational speed set by these arithmetic processes V and O, the drive control unit 23 calculates the tilt of the hydraulic pump 6 and the fuel injection flow rate of the engine 5, and commands corresponding to these are given to the engine. It is output to the control part 10 and the regulator 12 (step S1).

  FIG. 4 is a flowchart showing the processing contents of the work state determination processing U of FIG. FIG. 7 is a graph showing the transition of the pump flow rate T time before the present time.

  4 and 7, in the work state determination process U, first, the input signal from the operation lever 9, the accelerator command signal from the first dial 14, and the discharge of the hydraulic pump 6 input by the pressure sensor 7. Based on the pressure, the target flow rate Qr currently requested is calculated and stored in the storage unit 18 (step U1).

  Next, the maximum value Q (t) max and the minimum value Q (T) min of the flow rate in the second elapsed period are read from the storage unit 18 (step U2), and the maximum change in the second elapsed period that is the difference between these values A flow rate ΔQ (t) is calculated (step U3).

  Next, the maximum value Q (T) max and the minimum value Q (T) min of the flow rate in the first elapsed period are read from the storage unit 18 (step U4), and the maximum of the first elapsed period, which is the difference between these values. The change flow rate ΔQ (T) is calculated (step U5).

  Then, the response coefficient A by the second dial 15 is input (step U6), the maximum change flow rate ΔQ (T) in the first elapsed period multiplied by the response coefficient A, and the maximum change in the second elapsed period. The flow rate ΔQ (t) is compared (step U7).

  That is, in this step U7, as shown in FIG. 7, it is assumed that the period when the flow rate change is greatest within the first period (the period of 2t to t in the illustrated example) is in the sudden load period. Determine how close the flow rate width ΔQ (t) in the second elapsed period (the period from t to the present) that is the most recent period from the maximum flow rate width ΔQ (T) at this time By doing so, it is determined whether or not the present is in the sudden load period. Specifically, in this embodiment, the response coefficient A is set to 0.8. In the present embodiment, the responsiveness coefficient A is input by the first dial 14, but the responsiveness coefficient A may be stored in the storage unit 18 in advance.

  Moreover, in the said step U7, it can also be determined whether it exists in a sudden load work period based on following formula (7).

Q (T) max ≧ qmax × {Nqb + ΔN (t)} (7)
Here, Nqb is calculated in advance as, for example, the engine speed for the hydraulic pump 6 to discharge the target flow rate Qr at the maximum tilt qmax. That is, when this inequality (7) is satisfied, the maximum flow rate Q in the first elapsed period is increased even if the engine speed is increased by the expected increased rotational speed ΔN (t) and the tilt of the hydraulic pump 6 is set to the maximum qmax. Since it is not possible to discharge (T) max, it can be determined that it is in a sudden load work period. On the other hand, when the inequality (7) is not satisfied, the engine speed is increased by the expected increase speed ΔN (t). Increases, the hydraulic pump 6 can discharge the maximum flow rate Q (T) max with the maximum tilt qmax, so that it can be determined that the normal working period is in effect.

  If it is determined in step U7 that it is in the sudden load work period (YES in step U7), the sudden load rotation speed calculation process V is executed, while it is determined that it is in the normal work period (step). The normal rotational speed calculation process O is executed at NO in U7.

  FIG. 5 is a flowchart showing the processing contents of the rapid load rotation speed calculation processing V of FIG. FIG. 8 is a graph showing the transition of the engine speed T time before the present time.

  With reference to FIGS. 5 and 8, in the rapid load rotation speed calculation process V, the engine rotation speed increase sections shown in the sections b1 to b8 in FIG. 8 are read from the storage unit 18 (step V1), and these increase sections b1. Based on ˜b8, the average value B of the rotation speed increase rate per unit time is calculated (step V2).

  Next, an expected increase rotational speed ΔN (t) after time t is calculated based on the average speed increase rate value B (step V3). Specifically, as shown in the equation (1), the expected increase rotational speed ΔN (t) is calculated by multiplying the rotational speed increase rate average value B by the time t.

  Next, the maximum value Q (T) max of the flow rate in the first elapsed period is calculated based on the equation (4) as an ideal rotation speed N1 that can be discharged at the maximum tilt qmax after the elapse of time t ( Step V4). That is, in this step V4, it is assumed that the maximum flow rate Q (T) max when going back to the past first time T is required when a second time t shorter than the first time T has elapsed. By calculating the ideal rotational speed N1 at which the hydraulic pump 6 can discharge the maximum flow rate Q (T) max at the maximum tilt qmax by the rotational speed increased according to the rotational speed increase rate average value B, Even when the maximum flow rate Q (T) max is actually requested after the second time t has elapsed, the increase in the rotational speed of the engine 5 is increased corresponding to the average rotational speed increase value B, that is, the past. The purpose is to suppress the increase in the number of revolutions with a proven track record.

  Next, the maximum tilt rotation speed N2 for the hydraulic pump 6 to discharge the target flow rate Qr calculated in the step U1 at the maximum tilt qmax is calculated (step V5). Specifically, it is calculated by the equation (5).

  Then, the ideal rotation speed N1 calculated as described above is compared with the maximum rotation speed N2 (step V6), and a larger rotation speed is adopted as the target rotation speed during a sudden load (steps V7, V8). ).

  Employing a larger rotational speed in this way can reduce the tilt of the hydraulic pump 6 by the larger rotational speed, and hence the hydraulic pump 6 can be operated even when the target flow rate increases rapidly thereafter. This is because the change in flow rate can be quickly dealt with by the tilt adjustment. That is, as shown in the equation (5), the pump tilt q and the engine speed N are inversely proportional to the flow rate of the hydraulic pump 6, and therefore, when the flow rate is constant, the engine speed is increased. The tilt can be suppressed as much as possible.

  FIG. 6 is a flowchart showing the processing contents of the normal rotational speed calculation processing of FIG.

  On the other hand, in the normal rotational speed calculation process O, the rotational speed N2 of the engine 5 (maximum rotational speed N2) at which the hydraulic pump 6 can discharge the target flow rate Qr at the maximum tilt qmax is calculated. Is adopted as the normal target rotational speed (step O1).

  As described above, according to the present embodiment, it is determined that the sudden load target rotation speed (N1 or N2) that is set when it is determined that there is a sudden load work period is not during the sudden load work period. Since the rotation speed is set to be equal to or higher than the normal rotation speed (N2), the tilt of the hydraulic pump 6 can be kept smaller than that in the normal operation.

  Therefore, according to the present embodiment, the target flow rate is suddenly increased thereafter by setting the rotational speed of the engine 5 as large as possible during the sudden load work period and keeping the tilt of the hydraulic pump 6 small correspondingly. In the case of increasing, it is possible to respond quickly by increasing the pump tilt.

  Therefore, according to the present embodiment, it is possible to suppress deterioration of responsiveness even when the target flow rate increases rapidly.

  Specifically, in the above-described embodiment, the maximum change flow rate ΔQ (T) during the past first elapsed period as in step U7 of FIG. 4 and the latest second period that is shorter than the first elapsed period. By comparing with the maximum change flow rate ΔQ (t) during the period, it can be determined whether or not it is in the sudden load period.

  Further, in the above embodiment, even when the maximum flow rate Q (T) max generated during the past T time becomes the target flow rate after t time shorter than this T time, as in step V4 of FIG. The ideal rotational speed N1 at which the hydraulic pump 6 can discharge at the maximum tilt qmax can be calculated from the engine speed (N1 + ΔN (t)) in which the target flow rate is increased according to the average speed increase rate B. Therefore, by setting the rotation speed equal to or higher than the ideal rotation speed N1 as the target rotation speed at the present time, even when it is necessary to discharge the maximum flow rate Q (T) max after elapse of t time, the engine rotation speed The increase rate can be suppressed to the rotation speed increase rate average value B or less.

  And in the said embodiment, when it determines with it being in a sudden load work period, like step V6 of FIG. 5, the hydraulic pump 6 discharges the said ideal rotation speed N1 and the target flow volume Qr by the maximum inclination qmax. Compared with the maximum possible rotation speed N2 and setting a large rotation speed as the target rotation speed, it is possible to suppress the target rotation speed during sudden load from becoming higher than necessary. The deterioration of the fuel consumption rate can be suppressed.

  Hereinafter, another embodiment will be described.

  FIG. 13 is a graph showing changes in power of the hydraulic pump T time before the present time. FIG. 14 is a graph showing changes in the discharge pressure of the hydraulic pump T time before the present time.

  Referring to FIGS. 2, 13, and 14, the storage unit 18 in the present embodiment stores the power of the hydraulic pump 6 in the first elapsed period and the rotational speed of the engine 5 in the first elapsed period (see FIG. 8). Is stored. The power of the hydraulic pump 6 is obtained by multiplying the flow rate of the hydraulic pump 6 and the discharge pressure. As a result, the storage unit 18 stores the flow rate of the hydraulic pump 6 in the first elapsed period and The transition of the discharge pressure is also stored.

  The target flow rate calculation unit 16 calculates the current target flow rate Qr based on the input signal from the operation lever 9 and the first dial 14 and the discharge pressure of the hydraulic pump 6 detected by the pressure sensor 7 as in the above embodiment. calculate. This target flow rate Qr is stored in the storage unit 18.

  Further, the target flow rate calculation unit 16 calculates the target power Wr at the present time by multiplying the target flow rate Qr by the discharge pressure of the hydraulic pump 6 detected by the pressure sensor 7.

  The difference calculation unit 17 subtracts the minimum power value W (T) min in the first elapsed period from the maximum power value W (T) max in the first elapsed period based on the information stored in the storage unit 18. The maximum change power ΔW (T) (first change power) in the first elapsed period is calculated. Further, the difference calculation unit 17 calculates the minimum power value in the second elapsed period from the maximum power value W (t) max in the second elapsed time from the present time to t time (second time) shorter than the T time. The maximum change power ΔW (t) (second maximum change power) in the second elapsed period obtained by subtracting W (t) min is calculated.

  The increase rate calculation unit 19 calculates an average value C of the increase rate per unit time of the discharge pressure of the hydraulic pump 6 in the first elapsed period. That is, the increase rate calculation unit 19 cuts out the sections c1 to c8 in which the discharge pressure is increasing from the transition of the discharge pressure of the hydraulic pump 6 shown in FIG. 14, and unit based on the increase sections c1 to c8. A discharge pressure increase rate C per hour is calculated.

  The first rotational speed calculation unit 21 calculates an expected increase discharge pressure ΔP (t) after elapse of time t based on the discharge pressure increase rate average value C using the following equation (8).

ΔP (t) = C × t (8)
Further, similarly to the above-described embodiment, the first rotation speed calculation unit 21 uses the equation (1) to predict the expected increase rotation speed ΔN (t) after elapse of t time based on the rotation speed increase rate average value B. Is also calculated.

  Further, the first rotational speed calculation unit 21 uses the relational expression (9) among the discharge pressure P of the hydraulic pump 6, the engine rotational speed N, the tilt q of the hydraulic pump 6, and the power W to calculate the first elapsed period. , The maximum tilt qmax of the hydraulic pump 6, the expected increased discharge pressure ΔP (t) after the elapse of time t, the rotation speed N3 to be the next target, and the pressure sensor The relationship between the current discharge pressure Pr detected by No. 7 and the expected increase rotational speed ΔN (t) is expressed by the following equation (10), and is expressed by the following equation (11) using this equation (10). Thus, the rotation speed N3 is calculated.

W = P × q × N (9)
W (T) max = (Pr + ΔP (t)) × qmax × (N3 + ΔN (t)) (10)
N3 = W (T) max / [{Pr + ΔP (t)} × qmax] −ΔN (t) (11)
According to this equation (11), the ideal rotational speed N3 (second ideal rotational speed) at which the hydraulic pump 6 can output the maximum power value W (T) max in the first elapsed period at the maximum tilt qmax after elapse of t time. Can be calculated.

  The second rotational speed calculation unit 22 is the rotational speed of the engine 5 for causing the hydraulic pump 6 to discharge the target flow rate Qr, and is a rotational speed N4 (hereinafter referred to as a low fuel consumption rotational speed N4) where the fuel consumption rate is as small as possible. Calculated). For example, the second rotational speed calculation unit 22 calculates the power (horsepower) of the engine 5 necessary for causing the hydraulic pump 6 to discharge the target flow rate Qr, and shows the engine rotational speed for outputting this power in FIG. Specify based on the map as shown. Specifically, in the map, an iso-fuel consumption line and an iso-horsepower line are set, and the intersection D1 and D2 of these two lines has a smaller engine speed (D1 in the illustrated example). It is specified by the two-rotation number calculation unit 22. As is clear from the figure, when outputting a specific horsepower, the fuel consumption tends to improve as the engine speed is reduced.

  The determination unit 20 multiplies the maximum change power ΔW (T) in the first elapsed period by the response coefficient A input by the second dial 15 and the maximum change power ΔW (t) in the second elapsed period. Are compared using the following formula (12).

ΔW (t) ≧ ΔW (T) × A (12)
Then, the determination unit 20 determines that the power required for the hydraulic pump 6 is suddenly increased when the expression (12) is satisfied, and the expression (12) is satisfied. When it is not satisfied, it is determined that it is in a normal work period.

  Further, when the determination unit 20 determines that it is in the sudden load work period, the determination unit 20 compares the ideal rotation number N3 with the low fuel consumption rotation number N4 and adopts a larger rotation number as the target rotation number.

  Hereinafter, processing executed by the controller 8 according to the above-described embodiment will be described.

  Although not shown, the overall flow of processing by the controller 8 according to this embodiment is the same as that in the above embodiment. That is, when the process is started, first, the current work state determination process X is executed. If it is determined that the work state determination process X is in the sudden load work period, the rapid load rotation speed calculation process F is executed. A rotational speed calculation process G is executed (see FIG. 2).

  Then, the drive control unit 23 calculates the tilt of the hydraulic pump 6 and the fuel injection amount of the engine 5 based on the set target rotational speed by these calculation processes F and G, and commands corresponding to these are sent to the engine control unit. 10 and the regulator 12 (corresponding to step S1).

  FIG. 10 is a flowchart showing the processing contents of the work state determination processing X according to another embodiment.

  With reference to FIGS. 10 and 13, in the work state determination process X, first, the input signal from the operation lever 9, the accelerator command signal from the first dial 14, and the discharge of the hydraulic pump 6 input by the pressure sensor 7. The target flow rate Qr and the target power Wr are calculated based on the pressure and stored in the storage unit 18 (step X1).

  Next, the maximum value W (t) max and the minimum value W (t) min of the power in the second elapsed period are read from the storage unit 18 (step X2), and the maximum change in the second elapsed period, which is the difference between these values. The power ΔW (t) is calculated (step X3).

  Next, the maximum value W (T) max and the minimum value W (T) min of the power in the first elapsed period are read from the storage unit 18 (step X4), and the maximum of the first elapsed period, which is the difference between these values. The change power ΔW (T) is calculated (step X5).

  Then, the response coefficient A by the second dial 15 is input (step X6), the maximum change power ΔW (T) in the first elapsed period multiplied by the response coefficient A, and the maximum change power in the second elapsed period. W (t) is compared (step X7).

  That is, in step X7, as shown in FIG. 13, it is assumed that the period when the power change is the largest in the first period (the period of 2t to t in the illustrated example) is in the sudden load period. Then, it is determined how close the power width ΔW (t) in the second elapsed period, which is the most recent period from the present time (t to present in the illustrated example), to the power width ΔW (T) at this time. Thus, it is determined whether or not the present is in the sudden load period. Specifically, in this embodiment, the response coefficient A is set to 0.8.

  In Step X7, it can also be determined whether or not it is in a sudden load work period based on the following equation (13).

W (T) max ≧ Pr × qmax × {Nwb + ΔN (t)} (13)
Here, Pr is the discharge pressure of the hydraulic pump 6 detected by the pressure sensor 7, and Nwb is, for example, an engine for causing the hydraulic pump 6 to discharge the target flow rate Qr, like the ideal rotation speed N3. The number of revolutions is 5 and the number of revolutions is as small as possible. In other words, when this inequality (13) is satisfied, the engine speed increases by the expected increase speed ΔN (t) and the maximum power W (( Since it is not possible to output T) max, it can be determined that it is in a sudden load work period. On the other hand, if the inequality (13) is not satisfied, the engine speed is increased by the estimated increase speed ΔN (t). If it increases, the hydraulic pump 6 can output the maximum power W (T) max at the maximum tilt qmax, so that it can be determined that the normal work period is being reached.

  If it is determined in step X7 that the vehicle is in the sudden load work period (YES in step X7), the sudden load rotation speed calculation process F is executed, while it is determined that it is in the normal work period (step). X7, NO), the normal rotational speed calculation process G is executed.

  Referring to FIGS. 11 and 14, in the sudden load rotational speed calculation process F, first, the predicted increased rotational speed ΔN (t) after the elapse of time t is obtained by executing steps V1 to V3 of the embodiment. calculate.

  And the increase area of the pump discharge pressure shown to the area c1-c8 of FIG. 14 is read from the memory | storage part 18 (step F1), and the discharge pressure increase rate average value C per unit time is calculated based on these increase areas c1-c8. (Step F2).

  Next, the expected increase discharge pressure ΔP (t) after t time is calculated based on the average value C of the discharge pressure increase rate (step F3). Specifically, the expected increase discharge pressure ΔP (t) is calculated by multiplying the above equation (8) discharge pressure increase rate average value C by time t.

  Next, based on the above equation (11), the maximum value W (T) max of the power of the hydraulic pump 6 in the first elapsed period can be output with the maximum tilt qmax after the elapse of time t. (Step F4). That is, in step F4, it is assumed that the maximum power W (T) max when going back to the past first time T is required when a second time t shorter than the first time T has elapsed. The hydraulic pump 6 can discharge the maximum power W (T) max at the maximum tilt qmax by the discharge pressure increased according to the discharge pressure increase rate average value C and the rotation speed increased according to the rotation speed increase rate average value B. By calculating the ideal rotational speed N3, the increase in the rotational speed of the engine 5 is increased even when the maximum power W (T) max is actually requested after the second time t has elapsed. An increase corresponding to the rate average value B, that is, an increase in the number of revolutions with a past record can be suppressed.

  Next, the engine speed for discharging the target flow rate Qr calculated in the step X1 and the fuel efficiency rate N4 for reducing the fuel consumption rate of the engine 5 is calculated (step F5). Specifically, among the intersections D1 and D2 between the equal fuel consumption line and the equal horsepower line shown in FIG. 9, the one having a small engine speed is specified.

  Then, the ideal rotation speed N3 calculated as described above is compared with the low fuel consumption rotation speed N4 (step F6), and a larger rotation speed is adopted as the target rotation speed (steps F7, F8). By adopting such a large rotational speed, the tilt of the hydraulic pump 6 can be reduced by an amount corresponding to the large rotational speed. Therefore, even if the target flow rate increases rapidly thereafter, the hydraulic pump 6 This is because the change in flow rate can be quickly dealt with by the tilt adjustment.

  On the other hand, in the normal rotational speed calculation process G, the rotational speed of the engine 5 for causing the hydraulic pump 6 to discharge the target flow rate Qr, which is the low fuel consumption rotational speed N4 that minimizes the fuel consumption rate, is calculated. Is adopted as the target rotational speed (step G1).

  As described above, according to the embodiment, the maximum change power ΔW (T) in the first elapsed period and the maximum change power ΔW (t) in the second elapsed period as shown in Step X7 of FIG. It can be used to determine whether or not it is in a sudden load work period.

  Further, according to the embodiment, as shown in step F4 of FIG. 8, the maximum power W (T) max generated during the past T time becomes the target power after elapse of t time shorter than this T time. Even in this case, the hydraulic pump 6 can output the target power at the maximum inclination qmax by the engine speed increased in accordance with the average speed increase rate value B and the discharge pressure increased in accordance with the average value of the discharge pressure increase rate. Since the current ideal rotational speed N3 can be calculated, it is necessary to output the maximum power W (T) max after elapse of time t by setting the rotational speed equal to or higher than the ideal rotational speed N3 as the current target rotational speed. Even if this occurs, the engine speed increase rate can be kept below the average engine speed increase value B in the first elapsed period.

  And in the said embodiment, when it determines with it being in a sudden load period as shown to step F6 of FIG. 11, larger one of the ideal rotation speed N3 and the fuel-efficient rotation speed N4 is set as a target rotation speed. Therefore, it is possible to suppress the target rotational speed from becoming larger than necessary, and to suppress deterioration of the fuel consumption rate.

  Note that the processing executed in each of the embodiments can be performed in parallel as shown in FIG.

  Specifically, the work state determination processes U and X are executed, respectively, and each of the determination processes U and X, depending on the determination result, the rapid load rotation speed calculation processes V and F or the normal rotation speed calculation process. When both O and G are executed and both of the rapid load speed calculation processes V and F are executed, the engine speed N1 to N4 employed in the processes V and F is the highest speed. The one having a higher value is adopted (step S0).

  According to the embodiment, the ideal rotation speed N1 (first ideal rotation speed) calculated assuming the future target flow rate, and the ideal rotation speed N3 (first rotation) calculated assuming the power of the hydraulic pump 6 in the future. (Two ideal rotation speeds), the maximum tilt rotation speed N2 and the low fuel consumption rotation speed N4 can be set as the target rotation speed, so that the future target flow rate and power can be ensured. In addition, it is possible to suppress the deterioration of responsiveness by suppressing the increase rate of the engine speed for ensuring these as small as possible.

1 is an overall view schematically showing an electrical configuration and a hydraulic system of a work machine according to an embodiment of the present invention. It is a block diagram which shows the structure of a controller functionally. It is a flowchart which shows the process performed by a controller. It is a flowchart which shows the processing content of the working state determination process U of FIG. It is a flowchart which shows the processing content of the rotation speed calculation process V for sudden loads of FIG. It is a flowchart which shows the processing content of the normal rotation speed calculating process of FIG. It is a graph which shows transition of the pump flow rate before T time from the present time. It is a graph which shows transition of the engine speed of T time before this time. It is a figure which shows the relationship between engine motive power, fuel consumption, rotation speed, and torque. It is a flowchart which shows the processing content of the working state determination process X which concerns on another embodiment. It is a flowchart which shows the processing content of the rotation speed calculation process F for sudden load which concerns on another embodiment. It is a flowchart which shows the processing content of the normal rotation speed calculating process G which concerns on another embodiment. It is a graph which shows transition of the pump power before T time from the present time. It is a graph which shows transition of the pump discharge pressure before T time from the present time. It is a flowchart which shows the process which concerns on another embodiment.

Explanation of symbols

B Rotational speed increase rate average value C Discharge pressure increase rate average value F, V Rapid load rotational speed calculation processing G, O Normal rotational speed calculation processing U, X Work state determination processing T First time t Second time N1, N3 Ideal rotation speed N2 Maximum tilt rotation speed N4 Low fuel consumption rotation speed 1 Engine controller 2 Hydraulic motor (actuator)
3 Hydraulic cylinder (actuator)
5 Engine 6 Hydraulic pump 7 Pressure sensor 8 Controller (control unit)
16 target flow rate calculation unit 17 difference calculation unit 18 storage unit 19 increase rate calculation unit 20 determination unit 21 first rotation number calculation unit 22 second rotation number calculation unit

Claims (12)

An engine, a variable displacement hydraulic pump driven by the engine, an actuator driven by hydraulic oil supplied from the hydraulic pump, and the hydraulic pump for discharging the hydraulic oil flow rate required for the actuator The engine control device is provided in a work machine including an adjusting means for adjusting the tilt of the engine according to the engine speed, and controls the engine speed based on a hydraulic oil flow rate required for the actuator. And
A rotational speed setting means for setting a target rotational speed of the engine based on a hydraulic oil flow rate required for the actuator;
A rotational speed adjusting means for adjusting the rotational speed of the engine based on the target rotational speed set by the rotational speed setting means;
Working state determination means for determining whether or not the hydraulic fluid flow rate required for the actuator is during a period of sudden load work that may increase rapidly,
The rotation speed setting means sets the normal target rotation speed when the work state determination means determines that it is not during the sudden load work period, while the work state determination means sets the target rotation speed during the heavy load work period. An engine control device characterized in that, when it is determined that there is an engine speed, a target rotational speed at a sudden load equal to or higher than the normal target rotational speed is set.   The working state determination means includes a storage unit that stores a transition of the discharge flow rate of the hydraulic pump in a first elapsed period from the current time to a first time before, and a minimum value from a maximum value of the discharge flow rate in the first elapsed period. Difference calculation for calculating the first maximum change flow rate obtained by subtracting the first maximum change flow rate and the second maximum change flow rate obtained by subtracting the minimum value from the maximum value of the discharge flow rate in the second elapsed period from the present time to the second time shorter than the first time. And a determination unit for determining whether or not a heavy load operation is being performed by comparing the first maximum change flow rate and the second maximum change flow rate. The engine control device described in 1.   The working state determination means includes a storage unit that stores a transition of power of the hydraulic pump in a first elapsed period from the current time to a first time before, and a minimum value from a maximum value of the power of the hydraulic pump in the first elapsed period. The first maximum change power obtained by subtracting the value and the second maximum change power obtained by subtracting the minimum value from the maximum value of the power of the hydraulic pump in the second elapsed period from the present time to the second time shorter than the first time. A difference calculating unit to calculate, and a determination unit that determines whether or not the vehicle is in a period of a heavy load operation by comparing the first maximum change power and the second maximum change power. The engine control device according to claim 1.   The engine speed setting unit is configured to specify an engine speed that is assumed to be necessary after a specific time has elapsed from a current time when it is determined that the engine is in the sudden load work period; Means for specifying an increase rate of the rotation speed when the target rotation speed during loading increases to the assumed rotation speed during the specified time, and an allowable increase rate allowed during the sudden load work period; and Means for specifying an ideal rotational speed that will increase to the assumed rotational speed when the specific time has elapsed according to an allowable increase rate, and at least a rotational speed that is equal to or higher than the ideal rotational speed is the target rotational speed at the time of sudden load The engine control device according to claim 1, wherein   The rotation speed setting means includes a storage unit for storing a change in the discharge flow rate of the hydraulic pump and a change in the engine speed during a first elapsed period from the present time to the first hour before, and an engine speed during the first elapsed period. An increase rate calculation unit that calculates an average value of the rotation speed increase rate per unit time as the allowable increase rate, and when the second time shorter than the first time has elapsed, according to the rotation speed increase rate average value A first rotation speed calculation unit that calculates a current rotation speed at which the hydraulic pump can discharge the maximum value of the discharge flow rate in the first elapsed period according to the rising engine rotation speed as a first ideal rotation speed; The engine control device according to claim 4, comprising:   The first rotation speed calculation unit is configured to calculate the first rotation speed based on the expected increase rotation speed when the second time has elapsed, the maximum value of the discharge flow rate during the first elapsed period, and the maximum tilt of the hydraulic pump. 6. The engine control apparatus according to claim 5, wherein one ideal rotation speed is calculated.   The rotation speed setting means stores the transition of the power of the hydraulic pump during the first elapsed period, and the increase rate calculating unit discharges the discharge pressure per unit time of the hydraulic pump during the first elapsed period. An average value of the increase rate is calculated, and the first rotation speed calculation unit increases according to the discharge pressure increasing rate average value and the rotation speed increase rate average value when the second time has elapsed. And calculating the current engine speed at which the hydraulic pump can output with the maximum tilt as the second ideal speed, and at least the first ideal speed. 6. The engine control device according to claim 5, wherein the engine speed is set to a target engine speed during a sudden load that is greater than or equal to a larger one of the number and the second ideal engine speed.   The rotational speed setting means includes a storage unit that stores a transition of a discharge flow rate of the hydraulic pump, a transition of power, and a transition of engine speed in a first elapsed period from a current time to a first hour before, and the first elapsed period The average value of the engine speed increase rate per unit time is calculated as the allowable increase rate, and the average value of the discharge pressure increase rate per unit time of the hydraulic pump discharge pressure during the first elapsed period is calculated. An engine speed that increases according to the average speed increase rate when a second time shorter than the first time elapses, and a discharge pressure that increases according to the discharge pressure increase rate average value The maximum value of the power of the hydraulic pump during the first elapsed period is calculated as the ideal rotational speed as the current rotational speed at which the hydraulic pump can output with the maximum tilt. The engine control apparatus according to claim 4, characterized in that it comprises a one rotation speed calculator.   Detection means for detecting the discharge pressure of the hydraulic pump is further provided, and the first rotation speed calculation unit includes an expected increase rotation speed and an expected increase discharge pressure when the second time has elapsed, 9. The engine control device according to claim 8, wherein the ideal rotational speed is calculated based on a discharge pressure and a maximum tilt of the hydraulic pump.   The rotational speed setting means specifies a low fuel consumption rotational speed with a low fuel consumption rate based on a preset map among engine rotational speeds for causing the hydraulic pump to discharge the hydraulic oil flow rate required for the actuator. A second rotational speed calculation unit that sets a larger one of the ideal rotational speed and the low fuel consumption rotational speed as the target rotational speed at the time of sudden load when it is determined that it is during the sudden load work period. The engine according to any one of claims 1 to 9, wherein when it is determined that the engine is not in the sudden load work period, the low fuel consumption rotational speed is set to a normal target rotational speed. Control device.   The rotation speed setting means includes a second rotation speed calculation unit that calculates the maximum rotation speed of the engine at which the hydraulic pump can discharge the hydraulic oil flow rate required for the actuator at the maximum tilt. When it is determined that it is during the sudden load work period, a larger one of the ideal rotation speed and the maximum rotation speed is set as the sudden load target rotation speed, while the sudden load work period The engine control device according to any one of claims 1 to 9, wherein when it is determined that the engine speed is not, the maximum rotation speed is set to a normal target rotation speed.   An engine, a variable displacement hydraulic pump driven by the engine, an actuator driven by hydraulic oil supplied from the hydraulic pump, and the hydraulic pump for discharging the hydraulic oil flow rate required for the actuator The working machine provided with the adjustment means which adjusts inclination of this according to the said engine speed, and the engine control apparatus of any one of Claims 1-11.

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