JP6550411B2 - Construction machinery - Google Patents

Description

  The present invention relates to a construction machine such as a hydraulic shovel provided with an exhaust gas purification device for purifying exhaust gas discharged from an engine.

  A construction machine, for example, a hydraulic shovel includes an engine and a hydraulic pump driven by the engine, and torque control is performed so that the absorption torque of the hydraulic pump does not exceed the output torque of the engine. In addition, the hydraulic drive circuit to which hydraulic fluid of hydraulic pump is supplied is provided, and this hydraulic drive circuit includes hydraulic actuators such as a boom cylinder, arm cylinder, and bucket cylinder that drive work machines such as boom, arm, and bucket. Alternatively, hydraulic devices such as a swing body, a swing motor for driving a traveling body, hydraulic actuators such as a traveling motor, and a direction control valve for controlling the operation of these hydraulic actuators are included. Recently, there has been a demand for purifying exhaust gas discharged from an engine in a hydraulic shovel having such a configuration.

  As a prior art related to such exhaust gas purification, a urea water tank for storing urea water supplied to an exhaust gas control means for purifying nitrogen oxides in exhaust gas discharged from an engine, and a urea water tank for storing urea aqueous solution An alarm lamp which lights up when the remaining amount of urea water decreases to a first predetermined amount, and the controller is provided with a remaining amount detecting means for detecting the remaining amount of the urea aqueous solution; The engine gradually decreases the maximum engine speed to a predetermined value within a range where the hydraulic actuator included in the hydraulic drive circuit can be operated according to the decrease of the remaining amount as the first predetermined amount decreases from the first predetermined amount. There is known a construction machine provided with rotation speed limiting means (see, for example, Patent Documents 1 and 2).

Patent No. 4847218 gazette Patent No. 4847219 gazette

  As in the prior art disclosed in Patent Documents 1 and 2 described above, in the construction machine provided with the exhaust gas control means, the operator is mounted on the construction machine although it is within the range restricted by the engine speed restriction means. By pressing the emergency operation button or the like, work using the hydraulic actuator can be continued.

  In such a situation, the urea aqueous solution is not replenished into the urea aqueous solution tank, and the remaining amount of urea aqueous solution decreases as the hydraulic pump is driven, or the post-processing device is regenerated during operation. When the engine output decreases in relation to the exhaust gas purification process, the engine speed decreases and it takes a long time to recover, so-called engine rotation down increases, or engine stall (hereinafter referred to as Since this simply leads to the occurrence of "en-st", the operability with respect to the hydraulic actuator is deteriorated, and the operability is rapidly deteriorated.

  The present invention has been made from the circumstances of the prior art as described above, and an object thereof is to provide a construction machine capable of maintaining good operability with respect to a hydraulic actuator and improving workability. .

  In order to achieve the above object, a construction machine according to the present invention comprises an engine, a variable displacement hydraulic pump driven by the engine, a regulator for controlling the tilt angle of the hydraulic pump, and the hydraulic pump A construction machine comprising: a hydraulic drive circuit including a hydraulic actuator operated by discharged pressure oil; and a controller controlling an absorption torque of the hydraulic pump via the regulator so as not to exceed an output torque of the engine An aftertreatment device for removing nitrogen oxides in exhaust gas discharged from the engine, a reducing agent for reducing nitrogen oxides in the exhaust gas, and an exhaust gas purification device including a reducing agent tank for storing the reducing agent; A target rotation number specifying device for specifying a target rotation number of the engine, and a rotation number detector for detecting an actual rotation number of the engine And a remaining amount detector for detecting the remaining amount of the reducing agent stored in the reducing agent tank, wherein the controller stores in advance a relationship between a target rotational speed of the engine and a base torque of the hydraulic pump. A base torque calculation unit that applies the target rotation speed of the engine specified by the target rotation speed specification device to the relationship stored in the storage device, and calculates the base torque of the hydraulic pump; In a state where the output of the engine is limited in relation to the purification process of the exhaust gas by the exhaust gas purification device, the target rotational speed and the actual speed of the engine are calculated from the base torque of the hydraulic pump calculated by the base torque calculator. A target absorption torque function for calculating a target absorption torque of the hydraulic pump by subtracting a correction torque which is obtained according to a difference from the rotational speed And a drive signal output unit for outputting a drive signal corresponding to the target absorption torque of the hydraulic pump calculated by the target absorption torque calculation unit to the regulator, the target absorption torque calculation unit including the target rotation When the difference of the number of revolutions obtained by subtracting the actual number of revolutions of the engine detected by the number of revolutions detector from the target number of revolutions of the engine designated by the number designation device is less than 0, the difference of the number of revolutions is large. The absolute value of the correction torque amount is increased as it becomes, and the absolute value of the correction torque amount is increased as the remaining amount of the reducing agent detected by the remaining amount detector decreases.

  According to the construction machine of the present invention, it is possible to maintain good operability with respect to the hydraulic actuator and to improve workability. Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

BRIEF DESCRIPTION OF THE DRAWINGS It is a general view which shows the structure of the hydraulic shovel mentioned as an example of the construction machine which concerns on 1st Embodiment of this invention. FIG. 2 is a hydraulic circuit diagram showing an internal configuration of a swing structure according to a first embodiment of the present invention. It is a block diagram which shows typically the hardware constitutions of the controller which concerns on 1st Embodiment of this invention. It is a block diagram showing functional composition of a controller concerning a 1st embodiment of the present invention. It is a block diagram showing functional composition of a controller concerning a 2nd embodiment of the present invention. It is a block diagram showing functional composition of a controller concerning a 3rd embodiment of the present invention.

  Hereinafter, the form for carrying out the construction machine concerning the present invention is explained based on a figure.

First Embodiment
FIG. 1 is an overall view showing a configuration of a hydraulic shovel 100 exemplified as an example of a construction machine according to a first embodiment of the present invention.

  The construction machine according to the first embodiment of the present invention comprises, for example, a hydraulic shovel 100 shown in FIG. The hydraulic shovel 100 includes a traveling body 11, a swing body 12 rotatably mounted on the upper side of the travel body 11 via a swing device 12A, and a front side of the swing body 12 and vertically pivoted. It comprises the front working machine 13 and the like.

  The traveling body 11 is disposed on both left and right sides of one end in the front-rear direction, and includes a traveling motor 11B that drives the crawler belt 11A. The pivoting device 12A has a pivoting motor (not shown) disposed therein. The traveling motor 11 </ b> B and the turning motor are configured by, for example, a hydraulic motor using hydraulic pressure as a power source.

  The revolving unit 12 is disposed at the front of the vehicle body, and has a cab 15 in which an operator rides, a counterweight 16 disposed at the rear of the vehicle body and maintaining the balance of the vehicle body, and the cab 15 and the counterweight 16 A machine room 17 disposed between them and storing an engine 21 (see FIG. 2) as a prime mover, a vehicle body cover 18 provided on the upper part of the machine room 17, and a tail pipe 19 attached to the vehicle body cover 18; have. In addition, the specific structure inside the revolving unit 12 will be described later.

  The front work machine 13 has a base end pivotably attached to the revolving unit 12 and a boom 13A pivoting in the vertical direction, and an arm pivotably attached to the tip of the boom 13A pivoting in the vertical direction 13B and a bucket 13C rotatably attached at the tip of the arm 13B and pivoted in the vertical direction.

  In addition, the front work machine 13 connects the swing body 12 and the boom 13A, and extends and retracts the boom cylinder 13a that rotates the boom 13A, and is disposed above the boom 13A and is configured with the boom 13A and the arm 13B. The arm cylinder 13b rotates the arm 13B by connecting and expanding and contracting, and has the bucket cylinder 13c connecting the arm 13B and the bucket 13C and rotating and contracting the bucket 13C by expanding and contracting.

  In addition, various attachments, such as a bucket 13C, exist in the hydraulic shovel 100, and the bucket 13C can be changed to a breaker (not shown) for excavating a bedrock or a small split machine (not shown) for crushing rocks. By using an attachment suitable for the content of the work, various work including digging and crushing can be performed.

  FIG. 2 is a hydraulic circuit diagram showing an internal configuration of the swing structure 12.

  As shown in FIG. 2, the swing structure 12 includes the above-described engine 21 and a variable displacement hydraulic pump 22 driven by the engine 21. The absorption torque of the hydraulic pump 22 is an engine by a controller 28 described later. The torque control is performed so as not to exceed the 21 output torque.

  In addition, the revolving unit 12 controls the tilt angle of the swash plate with respect to the rotation shaft of the hydraulic pump 22 by adjusting the target rotation number specifying device 23 that designates the target rotation speed of the engine 21 and adjusts the displacement of the hydraulic pump 22 A regulator 24 and a main relief valve 25 that defines the maximum discharge pressure of the hydraulic pump 22 are provided. The target rotational speed specifying device 23 is installed in the driver's cab 15, and is configured of a dial-type operation panel operated by the operator.

  Further, the revolving unit 12 is specified by the rotation speed sensor 26 as a rotation speed detector for detecting the actual rotation speed of the engine 21, the rotation control unit 27 for controlling the rotation speed of the engine 21, and the target rotation speed specifying device 23 The controller 28 outputs a control signal corresponding to the target rotational speed of the engine 21 to the rotation control unit 27 and outputs a drive signal for driving the regulator 24.

  The rotation control unit 27 includes, for example, a governor control motor and a fuel injection device (not shown). The controller 28 inputs a command signal from the target rotation number specifying device 23, performs predetermined arithmetic processing, and outputs a control signal to the governor control motor. The governor control motor rotates in response to the control signal, and controls the fuel injection amount of the fuel injection device so that the target rotation speed specified by the target rotation speed specifying device 23 can be obtained.

  FIG. 3 is a block diagram schematically showing the hardware configuration of the controller 28 which performs such arithmetic processing.

  As shown in FIG. 3, although not shown, the controller 28 stores, for example, a central processing unit (CPU) 28A that performs various calculations for controlling the entire operation of the vehicle body and a program for executing calculations by the CPU 28A. Between a storage device 28B such as a read only memory (ROM) 28B1 or a hard disk drive (HDD) 28B2 and a random access memory (RAM) 28C serving as a work area when the CPU 28A executes a program And an input / output interface 28D for inputting / outputting various information and signals.

  In such a hardware configuration, a program stored in a recording medium such as the ROM 28B1 or the HDD 28B2 or an optical disk (not shown) is read out to the RAM 28C and operates according to the control of the CPU 28A, whereby the program (software) and hardware cooperate. In operation, functional blocks that implement the functions of the controller 28 are configured. The details of the functional configuration of the controller 28 that characterizes the first embodiment of the present invention will be described later.

  Furthermore, the swing body 12 has a hydraulic drive circuit 31 to which pressure oil discharged from the hydraulic pump 22 is supplied. The hydraulic drive circuit 31 includes a hydraulic cylinder such as a boom cylinder 13a, an arm cylinder 13b, and a bucket cylinder 13c for driving the front working machine 13 such as the boom 13A, the arm 13B, and the bucket 13C, or a rotating body 12, a traveling body 11 includes hydraulic devices such as a swing motor that drives 11 and hydraulic actuators such as a traveling motor 11B and a direction control valve (not shown) that controls the operation of these hydraulic actuators.

  Further, the rotating body 12 has an exhaust pipe (pipe) 32 connected to an exhaust port (not shown) of the engine 21, and the exhaust pipe 32 leads the exhaust gas discharged from the engine 21 to the tail pipe 19. , It is made to discharge | release this tail pipe 19 outside. At this time, since the exhaust gas discharged from the engine 21 contains nitrogen oxides (NOx) which are harmful substances, the hydraulic shovel 100 contains nitrogen oxides in the exhaust gas discharged from the engine 21. An exhaust gas purification device 33 including an aftertreatment device (not shown) to be removed is provided.

  Specifically, the exhaust gas purification apparatus 33 is installed in a reducing agent for reducing nitrogen oxides contained in exhaust gas, a reducing agent tank for storing the reducing agent, and the inside of the engine 21 and executes the purification process of the exhaust gas. And an exhaust gas processing unit 334 described later. The reducing agent in the reducing agent tank is made of, for example, ammonia, and the reducing agent tank is made of, for example, a urea aqueous solution tank 332 which stores ammonia in the form of an aqueous solution of urea water 331. A residual amount detector 333 for detecting the residual amount of urea water 331 stored in the urea aqueous solution tank 332 is attached to the urea aqueous solution tank 332, and the residual amount detector 333 is electrically connected to the controller 28. It is done.

  For example, although not shown, the remaining amount detector 333 is a float floating on the surface of the urea water 331 in the urea water tank 332, and a cylindrical shape which restricts the radial movement of the float and guides the float in the vertical direction. The guide consists of: Then, the float is guided by the guide as the urea water 331 in the urea water tank 332 decreases, and a current corresponding to the height position of the float floating on the surface of the urea water 331 is output to the controller 28. It becomes possible to detect the remaining amount of urea water 331 in the urea water tank 332.

  For example, although not shown, the exhaust gas processing unit 334 is disposed upstream of the reduction catalyst provided in the exhaust pipe 32 and the exhaust catalyst 32 in the exhaust pipe 32, and urea is injected into the exhaust pipe 32 to inject urea water 331 into the exhaust pipe 32. A water injection device, a urea water pump for supplying urea water 331 to the urea water injection device, a supply pipe having one end connected to the urea water pump and the other end immersed in the urea water 331 in the urea water tank 332 It consists of

  Therefore, the urea water pump supplies the urea water 331 to the urea water injection device by pumping up the urea water 331 in the urea water tank 332 through the supply pipe, and the urea water injection device is injected into the exhaust pipe 32 from this urea water injection device. The urea water 331 is hydrolyzed by the heat of the exhaust gas discharged from the engine 21. Then, the generated ammonia is reductively reacted with nitrogen oxides in the exhaust gas at the reduction catalyst to decompose the nitrogen oxides into harmless water and nitrogen for purification.

  Here, in the first embodiment of the present invention, the engine 21 serves as a drive source of the hydraulic pump 22. Therefore, the engine 21 continues to operate with the drive of the hydraulic pump 22. Is consumed, the urea water 331 in the urea water tank 332 is reduced. At this time, when the urea water 331 in the urea water tank 332 decreases to a predetermined value, the output of the engine 21 is suppressed and limited. However, the operator operates the emergency operation button (see FIG. By pressing (not shown) or the like, the operation using the hydraulic actuator can be continued within the range of the output of the engine 21.

  Next, a specific functional configuration of the controller 28 according to the purification process of exhaust gas, which is a feature of the first embodiment of the present invention, will be described in detail with reference to FIG. FIG. 4 is a block diagram showing a functional configuration of the controller 28 according to the first embodiment of the present invention.

  As shown in FIG. 4, the controller 28 includes a base torque calculator 281, a rotational speed difference calculator 282, a correction torque calculator 283, a correction coefficient calculator 284, a multiplier 285, an adder 286, and a drive signal output unit 287. Is composed including.

  The base torque calculator 281 calculates a target absorption torque of the hydraulic pump 22 as a base torque (reference torque) so that the absorption torque of the hydraulic pump 22 does not exceed the output torque of the engine 21. Specifically, the base torque calculation unit 281 inputs a command signal of the target rotation number of the engine 21 from the target rotation number specification device 23 and applies this to the table A stored in advance in the storage device 28B. The base torque of the hydraulic pump 22 corresponding to the target rotational speed is calculated.

  In the table A of the storage device 28B, the base torque of the hydraulic pump 22 increases as the target rotational speed of the engine 21 increases as the relationship between the target rotational speed of the engine 21 and the base torque of the hydraulic pump 22 A functional relationship is shown in which the base torque of the hydraulic pump 22 decreases when the target rotational speed exceeds a predetermined value. In this case, the horizontal axis of the table A shown in FIG. 4 is the target rotational speed of the engine 21, and the vertical axis is the base torque of the hydraulic pump 22.

  The rotational speed difference calculation unit 282 subtracts the target rotational speed of the engine 21 specified by the target rotational speed specification device 23 from the actual rotational speed of the engine 21 detected by the rotational speed sensor 26.

  The correction torque calculation unit 283 calculates a correction torque for correcting the base torque of the hydraulic pump 22 in a state where the output of the engine 21 is limited in relation to the purification process of the exhaust gas by the exhaust gas purification device 33. Specifically, the correction torque calculation unit 283 inputs the difference between the actual rotation number of the engine 21 and the target rotation number from the rotation number difference calculation unit 282, and applies this to the table B stored in advance in the storage device 28B. By doing this, the correction torque corresponding to the difference is calculated.

  In the table B of the storage device 28B, when the difference between the actual rotation number of the engine 21 and the target rotation number is 0 or more, the correction torque is 0 and the difference between the actual rotation number of the engine 21 and the target rotation number is less than 0 There is shown a functional relationship in which the correction torque decreases as the difference between the actual rotation speed of the engine 21 and the target rotation speed becomes smaller. In this case, the horizontal axis of the table B shown in FIG. 4 is the difference between the actual rotation number of the engine 21 and the target rotation number, and the vertical axis is the correction torque.

  The correction coefficient calculation unit 284 changes the correction amount of the correction torque calculated by the correction torque calculation unit 283 according to the remaining amount of the urea water 331 detected by the remaining amount detector 333. Specifically, the correction coefficient calculation unit 284 inputs the remaining amount of the urea water 331 detected by the remaining amount detector 333 and applies this to the table C stored in advance in the storage device 28B. The correction coefficient (torque ratio) of the correction torque corresponding to the remaining amount of the urea water 331 is calculated.

  The table C of the storage device 28B shows a functional relationship in which the correction coefficient of the correction torque increases as the remaining amount of the urea water 331 in the urea water tank 332 decreases. In this case, the horizontal axis of the table C shown in FIG. 4 is the remaining amount of urea water 331 in the urea water tank 332, and the vertical axis is the correction coefficient of the correction torque.

  The multiplication unit 285 multiplies the correction torque calculated by the correction torque calculation unit 283 by the correction coefficient of the correction torque calculated by the correction coefficient calculation unit 284 to obtain a correction amount (negative value) of the correction torque. That is, a correction amount (hereinafter simply referred to as “reduction torque amount”) to the base torque of the hydraulic pump 22 is calculated. As a result, as the remaining amount of the urea water 331 detected by the remaining amount detector 333 decreases, the absolute value of the reduction torque amount increases.

  The adding unit 286 calculates the target absorption torque of the hydraulic pump 22 by adding the base torque of the hydraulic pump 22 calculated by the base torque calculating unit 281 and the reduction torque amount calculated by the multiplying unit 285. The drive signal output unit 287 outputs a drive signal corresponding to the target absorption torque of the hydraulic pump 22 calculated by the addition unit 286 to the regulator 24.

  Therefore, the rotational speed difference calculation unit 282, the correction torque calculation unit 283, the correction coefficient calculation unit 284, the multiplication unit 285, and the addition unit 286 limit the output of the engine 21 in relation to the exhaust gas purification process by the exhaust gas purification device 33. In the selected state, the target absorption of the hydraulic pump 22 is subtracted from the base torque of the hydraulic pump 22 calculated by the base torque calculation unit 281 by subtracting the correction torque obtained according to the difference between the actual rotation number of the engine 21 and the target rotation number. It functions as a target absorption torque calculator that calculates torque.

  According to the hydraulic shovel 100 according to the first embodiment of the present invention configured as described above, the operator operates in a situation where the remaining amount of urea water 331 in the urea water tank 332 decreases with the driving of the hydraulic pump 22. Even if the emergency operation button or the like in the chamber 15 is pressed to continue the work, the correction taking into consideration the remaining amount of the urea water 331 is appropriate with respect to the base torque of the hydraulic pump 22 calculated by the base torque calculator 281 Can be done.

  Therefore, as in the first embodiment of the present invention, when the output state of the engine 21 limited according to the remaining amount of the urea water 331 is different, the load of the hydraulic drive circuit 31 causes the rotational speed of the engine 21 to be increased. Even if the engine speed changes, the rotation speed of the engine 21 decreases and returns by decreasing the torque reduction amount corresponding to the remaining amount of urea water 331, that is, making the gain of the speed sensing control variable. In addition to reducing the phenomenon of so-called engine rotation down, it is possible to prevent the occurrence of an engine stall. Thus, good operability can be maintained for the hydraulic actuator, and the workability can be improved.

  Moreover, in the hydraulic shovel 100 according to the first embodiment of the present invention, the remaining amount detection is performed by using the table C stored in advance in the storage device 28B in the calculation of the correction coefficient of the correction torque by the correction coefficient calculation unit 284. As the absolute value of the torque reduction amount increases as the remaining amount of the urea water 331 detected by the sensor 333 decreases, a problem occurs in the engine 21 even if the urea water 331 in the urea water tank 332 becomes small. The operator can operate the hydraulic actuator smoothly. Thereby, the efficiency of the work by the hydraulic shovel 100 can be improved.

Second Embodiment
FIG. 5 is a block diagram showing a functional configuration of the controller 28 according to the second embodiment of the present invention.

  The second embodiment of the present invention is different from the first embodiment in that the controller 28 according to the first embodiment is, as shown in FIG. 4, a correction torque calculator 283, a correction coefficient calculator 284 and a multiplication. While the controller 28 according to the second embodiment includes the unit 285, as shown in FIG. 5, for example, instead of the correction torque calculation unit 283, the correction coefficient calculation unit 284 and the multiplication unit 285. The selection unit 288 and the correction torque calculation units 283A to 283C are included.

  In this case, when the remaining amount of the urea water 331 detected by the remaining amount detector 333 is larger than the first predetermined amount a, the selection unit 288 selects the calculation processing of the correction torque by the correction torque calculation unit 283A. In addition, in the selection unit 288, the remaining amount of the urea water 331 detected by the remaining amount detector 333 is equal to or less than the first predetermined amount a, and the remaining amount of the urea water 331 detected by the remaining amount detector 333 is When it is equal to or greater than the second predetermined amount b set smaller than the first predetermined amount a, the calculation processing of the correction torque by the correction torque calculation unit 283B is selected. Furthermore, when the remaining amount of the urea water 331 detected by the remaining amount detector 333 is smaller than the second predetermined amount b, the selection unit 288 selects the calculation process of the correction torque by the correction torque calculation unit 283C.

  The correction torque calculation unit 283A inputs the difference between the actual rotation number of the engine 21 and the target rotation number from the rotation number difference calculation unit 282 when the calculation processing of the correction torque by the correction torque calculation unit 283A is selected by the selection unit 288. The correction torque corresponding to the difference is calculated by applying this to the table D stored in advance in the storage device 28B.

  Similar to the table B, when the difference between the actual rotation number of the engine 21 and the target rotation number is 0 or more, the correction torque is 0, and the actual rotation number and the target rotation number of the engine 21 are A functional relationship is shown in which the correction torque decreases as the difference between the actual rotation speed of the engine 21 and the target rotation speed decreases as the difference between the values of and. In this case, the horizontal axis of the table D shown in FIG. 5 is the difference between the actual rotation speed of the engine 21 and the target rotation speed, and the vertical axis is the correction torque.

  The correction torque calculation unit 283B inputs the difference between the actual rotation number of the engine 21 and the target rotation number from the rotation number difference calculation unit 282 when the selection torque processing unit 283B selects the calculation processing of the correction torque by the selection unit 288. The correction torque corresponding to the difference is calculated by applying this to the table E stored in advance in the storage device 28B.

  In the table E of the storage device 28B, as in the case of the table B, when the difference between the actual rotation number of the engine 21 and the target rotation number is 0 or more, the correction torque becomes 0, and the actual rotation number and the target rotation number of the engine 21 The correction torque decreases as the difference between the actual rotation speed of the engine 21 and the target rotation speed becomes smaller when the difference of is smaller than 0, and the functional relationship in which the reduction rate is larger than that of the table D is shown. In this case, the horizontal axis of the table E shown in FIG. 5 is the difference between the actual rotation speed of the engine 21 and the target rotation speed, and the vertical axis is the correction torque.

  The correction torque calculation unit 283C inputs the difference between the actual rotation number of the engine 21 and the target rotation number from the rotation number difference calculation unit 282 when the selection torque processing unit 283C selects the calculation processing of the correction torque by the selection unit 288. By applying this to the table F stored in advance in the storage device 28B, the correction torque corresponding to the difference is calculated.

  Similar to the table B, when the difference between the actual rotation number of the engine 21 and the target rotation number is 0 or more, the correction torque is 0, and the actual rotation number and the target rotation number of the engine 21 are The correction torque decreases as the difference between the actual rotation speed of the engine 21 and the target rotation speed becomes smaller when the difference of is smaller than 0, and the functional relationship in which the reduction rate is larger than that of the table E is shown. In this case, the horizontal axis of the table F shown in FIG. 5 is the difference between the actual rotation speed of the engine 21 and the target rotation speed, and the vertical axis is the correction torque.

  The configuration of the other second embodiment is the same as the configuration of the first embodiment, and the same or corresponding parts will be denoted by the same reference symbols, without redundant description. Also in the hydraulic excavator 100 according to the second embodiment of the present invention configured as described above, the same function and effect as those of the above-described first embodiment can be obtained.

Third Embodiment
FIG. 6 is a block diagram showing a functional configuration of the controller 28 according to the third embodiment of the present invention.

  The difference between the third embodiment of the present invention and the first embodiment described above is that the controller 28 according to the first embodiment includes a correction coefficient calculation unit 284 and a multiplication unit 285 as shown in FIG. On the other hand, in the controller 28 according to the third embodiment, instead of the correction coefficient calculation unit 284 and the multiplication unit 285, for example, as shown in FIG. The determination unit 290, the ON / OFF switching unit 291, and the minimum value selection unit 292 are included.

  In this case, the correction torque calculation unit 283D inputs the difference between the actual rotation number of the engine 21 and the target rotation number from the rotation number difference calculation unit 282 and applies this to the table G stored in advance in the storage device 28B. The correction torque corresponding to the difference is calculated.

  Similar to the table B, when the difference between the actual rotation number of the engine 21 and the target rotation number is 0 or more, the correction torque is 0, and the actual rotation number and the target rotation number of the engine 21 are The correction torque decreases as the difference between the actual rotation speed of the engine 21 and the target rotation speed becomes smaller when the difference of is smaller than 0, and the functional relationship in which the reduction rate is larger than that of the table B is shown. In this case, the horizontal axis of the table G shown in FIG. 6 is the difference between the actual rotation speed of the engine 21 and the target rotation speed, and the vertical axis is the correction torque.

  By the way, in operating the purification process of the exhaust gas by the exhaust gas purification apparatus 33 according to the third embodiment of the present invention, the residue of the white product is deposited in the exhaust pipe 32 along with the use of the urea water 331. This residue may cause the engine 21 to malfunction by closing the exhaust gas passage in the exhaust pipe 32. Therefore, in the third embodiment of the present invention, the regeneration processing unit 289 performs the regeneration processing of the post-processing device for removing the residue accumulated in the exhaust pipe 32, so-called purge control, at a predetermined frequency. .

  Specifically, for example, the regeneration processing unit 289 injects the fuel from the fuel injection device of the rotation control unit 27 in the exhaust stroke at a frequency of once every 30 hours, and oxidizes the unburned fuel with the oxidation catalyst to produce an exhaust gas. By forcibly raising the temperature of the exhaust gas, it is possible to remove the residue in the exhaust pipe 32 by the heat of the exhaust gas.

  The reproduction processing execution judgment unit 290 judges whether or not the reproduction processing of the post-processing device by the reproduction processing unit 289 is performed. For example, from the time when the reproduction processing unit 289 ends the reproduction processing of the post-processing device described above The time is measured, and when the measured time passes 30 hours, it is determined that the regeneration processing of the post-processing device by the regeneration processing unit 289 is executed, and if the measured time does not exceed 30 hours, the regeneration processing unit 289 It is determined that the regeneration processing of the post-processing apparatus by the above is not executed.

  When it is determined by the regeneration processing execution determination unit 290 that the regeneration processing by the regeneration processing unit 289 has been executed, the ON / OFF switching unit 291 is switched to the ON state and the correction torque calculation unit 283D The calculation result is output to minimum value selection unit 292, and when it is determined by regeneration processing execution determination unit 290 that regeneration processing of the post-processing device by regeneration processing unit 289 is not executed, switching to the OFF state is made to calculate correction torque. The calculation result of the correction torque by the unit 283D is not output to the minimum value selection unit 292.

  The minimum value selection unit 292 compares the correction torque calculated by the correction torque calculation unit 283 with the correction torque calculated by the correction torque calculation unit 283D, and selects the smaller one of these correction torques, that is, the minimum value. And output to the addition unit 286. The configuration of the other third embodiment is the same as the configuration of the first embodiment, and the same or corresponding parts will be denoted by the same reference symbols, without redundant description.

  According to the hydraulic shovel 100 according to the third embodiment of the present invention configured as described above, in addition to the same function and effect as the first embodiment described above, the engine can be used along with the regeneration processing of the post-processing device during operation. Even when the output 21 is rapidly reduced, the base torque of the hydraulic pump 22 calculated by the base torque calculator 281 can be appropriately corrected in consideration of the influence of the regeneration process of the post-processing device. As a result, excellent operability with respect to the hydraulic actuator can be realized, and the exhaust gas purification process by the exhaust gas purification device 33 can be continued, so high reliability can be ensured in the operation of the hydraulic shovel 100.

  The embodiments of the present invention described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.

  Further, in the third embodiment of the present invention, the reproduction processing execution determination unit 290 measures the time from the time when the reproduction processing unit 289 ends the reproduction processing of the post-processing apparatus, thereby measuring the time after processing by the reproduction processing unit 289. Although the case of judging the execution of the regeneration process has been described, the present invention is not limited to this case, and the regeneration process execution determining unit 290 measures the differential pressure before and after the post-processing device to obtain the regeneration process unit 289. It may be determined whether or not the regeneration process of the post-processing device is performed.

11: traveling body, 11B: traveling motor, 12: revolving body, 13: front working machine, 13a: boom cylinder, 13b: arm cylinder, 13c: bucket cylinder, 15: cab, 18: vehicle body cover, 19: tail pipe Reference Signs List 21 engine 22 hydraulic pump 23 target rotation number specifying device 24 regulator 25 main relief valve 26 rotation number sensor (actual rotation number detector) 27 rotation control unit 28 controller 28A: CPU, 28B: storage device, 28B1: ROM, 28B2: HDD, 28C: RAM, 28D: input / output interface, 31: hydraulic drive circuit, 32: exhaust pipe, 33: exhaust gas purification device 100: hydraulic shovel (construction machine , 281 ... base torque calculator, 282 ... rotational speed difference calculator (target absorption torque calculator), 283, 283 -283D ... correction torque calculation unit (target absorption torque calculation unit), 284 ... correction coefficient calculation unit (target absorption torque calculation unit), 285 ... multiplication unit (target absorption torque calculation unit), 286 ... addition unit (target absorption torque calculation 287: drive signal output unit 288 selection unit 289 regeneration processing unit 290 regeneration processing execution determination unit 291 ON / OFF switching unit 292 minimum value selection unit 331 urea water (reducing agent ), 332 ... urea water tank (reductant tank), 333 ... remaining amount detector, 334 ... exhaust gas processing unit

Claims (2)

A hydraulic drive circuit including an engine, a variable displacement hydraulic pump driven by the engine, a regulator for controlling a tilt angle of the hydraulic pump, and a hydraulic actuator operated by pressure oil discharged from the hydraulic pump; A controller configured to control an absorption torque of the hydraulic pump via the regulator so as not to exceed an output torque of the engine;
An aftertreatment device for removing nitrogen oxides in exhaust gas discharged from the engine, a reducing agent for reducing nitrogen oxides in the exhaust gas, and an exhaust gas purification device including a reducing agent tank for storing the reducing agent;
A target speed specifying device for specifying a target speed of the engine;
A rotation number detector for detecting an actual rotation number of the engine;
A residual amount detector for detecting the residual amount of the reducing agent stored in the reducing agent tank;
The controller
A storage device in which the relationship between the target engine speed of the engine and the base torque of the hydraulic pump is stored in advance;
A base torque calculation unit that calculates the base torque of the hydraulic pump by applying the target rotation speed of the engine specified by the target rotation speed specification device to the relationship stored in the storage device;
In a state where the output of the engine is limited in relation to the purification process of the exhaust gas by the exhaust gas purification device, the target rotational speed and the actual speed of the engine are calculated from the base torque of the hydraulic pump calculated by the base torque calculator. A target absorption torque calculation unit that calculates a target absorption torque of the hydraulic pump by subtracting a correction torque that is obtained according to a difference from the rotational speed;
A drive signal output unit that outputs a drive signal corresponding to the target absorption torque of the hydraulic pump calculated by the target absorption torque calculation unit to the regulator;
The target absorption torque calculation unit is configured such that the difference between the rotational speeds obtained by subtracting the actual rotational speed of the engine detected by the rotational speed detector from the target rotational speed of the engine specified by the target rotational speed specification device is less than 0. In this case, the absolute value of the correction torque amount is increased as the rotational speed difference increases, and the absolute value of the correction torque amount is decreased as the remaining amount of the reducing agent detected by the remaining amount detector decreases. Construction machinery characterized by increasing. In the construction machine according to claim 1,
The controller
A regeneration processing unit that performs regeneration processing of the post-processing device that removes the residue accumulated in the pipe in the exhaust gas purification device with the use of the reducing agent;
And a reproduction processing execution determination unit that determines whether the reproduction processing unit is to execute the reproduction processing of the post-processing device.
The construction machine is characterized in that the target absorption torque calculation unit increases the absolute value of the correction amount of the correction torque when it is determined that the regeneration processing of the post-processing device is executed by the regeneration processing execution determination unit. .