JP2012145083A - Exhaust gas cleaning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas cleaning system capable of preventing the breakage of a DPF when forbidding regeneration.SOLUTION: In the case although the regeneration should be originally started due to PM deposition progression, automatic regeneration is not started while the regeneration is forbidden, operation regulation and notification of the same are carried out when a PM accumulating quantity exceeds the fifth threshold value (S10→S20→S30→S40→S90→S100→S110). The rotational frequency of an engine is reduced, the discharging flowing rate to the hydraulic pump 11 is reduced by inclining operation, thereby the operation of a hydraulic shovel regulated. By the regulation of the operation, an operator is urged to stop the indoor operation and to move the hydraulic shovel to the regeneratable location. As a result, the regeneration is carried out in the regeneratable location, the breakage of the DPF can be prevented.

Description

  The present invention relates to an exhaust gas purification system, and in particular, the particulate matter contained in the exhaust gas is collected by a filter to purify the exhaust gas, and the particulate matter collected in the filter is appropriately incinerated and removed. The present invention relates to an exhaust gas purification system that regenerates exhaust gas.

  Construction machines such as hydraulic excavators are equipped with a diesel engine as a driving source, but the amount of particulate matter (PM: particulate matter: hereinafter referred to as PM) discharged from this diesel engine is NOx, Regulations have been strengthened year by year along with CO and HC. An exhaust gas purification system that collects PM with a filter called a diesel particulate filter (DPF: Diesel Particulate Filter) and reduces the amount of PM discharged to the outside is known for such regulations. . In this exhaust gas purification system, when the amount of PM accumulation on the filter increases, the filter clogs, which increases the exhaust pressure of the engine and induces deterioration of fuel consumption. The collected PM is combusted as appropriate to remove the clogging of the filter, and the filter is regenerated.

  The regeneration of the filter is usually performed by using an oxidation catalyst. The oxidation catalyst may be disposed upstream of the filter, directly supported by the filter, or both. In either case, in order to activate the oxidation catalyst, the temperature of the exhaust gas Must be higher than the activation temperature of the oxidation catalyst. If the exhaust gas temperature is high enough, it will self-regenerate, but the exhaust gas temperature may not be sufficient and self-regeneration may not be possible, or self-regeneration may not sufficiently incinerate and remove PM. There is a technique called forced regeneration in which the temperature is raised to a temperature higher than the activation temperature. In this forced regeneration, a method of raising the temperature of exhaust gas by performing sub-injection (post-injection) for injecting fuel in the expansion stroke after in-cylinder main injection of the engine, exhaust by a fuel injection device for regeneration provided in the exhaust pipe There is a technique for injecting fuel into exhaust gas flowing through a pipe to raise the temperature of the exhaust gas.

  Further, the forced regeneration of the filter includes manual regeneration that starts regeneration by an operator's operation input and automatic regeneration that automatically starts regeneration. Manual regeneration is performed as follows. First, the PM accumulation amount (accumulation amount) of the filter is estimated, and when the PM accumulation amount reaches a preset threshold value, the operator is warned that manual regeneration is performed. When the operator operates the manual regeneration switch, regeneration starts. Patent Document 1 discloses a technique related to manual regeneration. On the other hand, automatic regeneration is performed when the PM accumulation amount reaches the threshold value or when a predetermined time has elapsed. Patent Document 2 discloses a technique related to automatic reproduction. In both manual regeneration and automatic regeneration, the PM accumulation amount is generally obtained by detecting the differential pressure across the filter and calculating based on the detected value of the differential pressure.

  By the way, construction machines such as wheel loaders and hydraulic excavators sometimes work in an environment where there are combustible materials. For example, as such work, there are a work of transporting wood chips indoors, a work of dismantling that generates dust and the like. When the filter is forcibly regenerated, the exhaust gas temperature is maintained at a high temperature for a predetermined time (for example, several minutes). Therefore, if the filter is forcibly regenerated in the above environment, there is a risk of ignition and danger.

  In this situation, in manual regeneration, the manual regeneration switch is not operated at the operator's discretion, and the construction machine is moved to a place where there is no flammable material (recyclable place) to ensure safety and start manual regeneration. To do.

  On the other hand, in automatic reproduction, since reproduction automatically starts regardless of the operator's judgment, a reproduction prohibiting means is provided, and automatic reproduction is prohibited by operating the reproduction prohibiting means according to the operator's judgment (Patent Document 2). Then, the operator appropriately suspends the work, moves the construction machine to a place where there is no flammable material (recyclable place), ensures safety, releases the prohibition of regeneration, and resumes automatic regeneration.

International Publication No. WO2009 / 060719 JP 2009-79500 A

  If the operation is continued while automatic regeneration (forced regeneration) is prohibited, PM will continue to accumulate, causing problems such as abnormal rise in the internal temperature of the filter due to combustion of a large amount of collected PM and damage to the DPF resulting therefrom. There is a possibility. For this reason, it may be possible to warn the operator that the operation is interrupted and the reproduction is prompted.

  However, if the operation is interrupted frequently, the work efficiency is lowered, so the operator does not always follow the warning. If the operator does not follow the warning and continues the work, PM deposition proceeds and the possibility of DPF breakage increases.

  An object of the present invention is to provide an exhaust gas purification system capable of preventing DPF breakage when regeneration is prohibited.

  (1) In order to achieve the above object, the present invention is mounted on a construction machine including a diesel engine and a plurality of driven bodies driven by power of the engine, and is disposed in an exhaust system of the engine. , A filter that collects particulate matter contained in exhaust gas, a particulate matter deposited on the filter by incineration, a regeneration device that regenerates the filter, and an instruction to start and stop the operation of the regeneration device In an exhaust gas purification system comprising a regeneration control device for performing regeneration and a regeneration prohibiting means for prohibiting operation of the regeneration device, warning means for giving a warning regarding regeneration, and after the warning means is activated, the regeneration control device operates the regeneration device. An operation restricting means for restricting the operations of the plurality of driven bodies when the regeneration prohibiting means prohibits the operation of the reproducing apparatus in spite of instructing the start.

  The operation of the operation restricting unit causes the operator to give up the continuation of the work and prompt the construction machine to move to a recyclable place. Since regeneration is performed at a recyclable place before the PM accumulation amount reaches the limit value, DPF breakage can be prevented.

  (2) In the above (1), preferably, the apparatus further comprises a deposit amount estimating means for estimating a deposit amount of the particulate matter deposited on the filter, and the regeneration control device, when the estimated deposit amount exceeds a first threshold value. Instructing the start of the operation of the regenerator, and the warning means gives a renewal start notice when the estimated accumulation amount exceeds a fourth threshold value which is less than the first threshold value.

  Thus, the operator can predict the start of regeneration and the subsequent operation restriction start, and can work in a planned manner.

  (3) In the above (1), preferably, the apparatus further comprises a deposit amount estimating means for estimating a deposit amount of the particulate matter deposited on the filter, and the regeneration control device, when the estimated deposit amount exceeds a first threshold value. Instructing the start of the operation of the regeneration device, the warning means warns that the regeneration is urged when the estimated accumulation amount exceeds a fourth threshold value that is equal to or greater than the first threshold value.

  As a result, the operator can predict the start of operation restriction, can work in a planned manner, and as a result of extending the warning time, the operator can concentrate on the work without being bothered by the warning.

  (4) In the above (1), preferably, the operation limiting means operates when the estimated accumulation amount exceeds a fifth threshold value that is equal to or greater than the first threshold value.

  This makes it possible to achieve both the DPF damage prevention effect and the workability when regeneration is prohibited. That is, by setting the fifth threshold value higher than the first threshold value, it is possible to extend the time when the operation restriction is started, to extend the indoor work time, and to ensure workability even when reproduction is prohibited. On the other hand, by setting the fifth threshold value to the same level as the first threshold value, the time when the operation restriction is started can be advanced. As a result, before a large amount of PM is accumulated, regeneration is performed at a recyclable place. Therefore, DPF breakage can be prevented more reliably.

  (5) In the above (1), preferably, the operation limiting means is activated when a predetermined time elapses after the warning means is activated.

  Thereby, the operator can recognize the work continuation possible time after warning and can work in a planned manner.

  (6) In the above (1), preferably, the operation limiting means limits the engine output.

  (7) In the above (1), preferably, the construction machine includes a hydraulic pump driven by the engine, and a hydraulic actuator driven by discharge oil of the hydraulic pump to drive the driven body. The operation limiting means limits the pump output of the hydraulic pump.

  With the configuration as described in the above (6) and (7), the operation limiting means can limit the operation of the driven body.

  (8) In the above (1), preferably, when the operation restricting means is activated, a notifying means for notifying that the operation is being restricted is provided.

  Thereby, the operator can recognize that the operation is being restricted.

  According to the present invention, it is possible to prevent the DPF from being damaged when regeneration is prohibited.

1 is a diagram illustrating an overall configuration of an exhaust gas purification system and a related configuration (first embodiment). It is a figure which shows the external appearance of a hydraulic shovel. It is a figure which shows the functional block of a controller. It is a flowchart which shows the content of the arithmetic processing by a controller. It is an example of the time passage of PM deposition amount. It is a flowchart which shows the content of the arithmetic processing by a controller (2nd Embodiment). It is an example of the time passage of PM deposition amount. It is a flowchart which shows the content of the arithmetic processing by a controller (3rd Embodiment). It is an example of the time passage of PM deposition amount. It is a flowchart which shows the content of the arithmetic processing by a controller (4th Embodiment). It is an example of the time passage of PM deposition amount.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

~Constitution~
FIG. 1 is a diagram showing an overall configuration and related configuration of an exhaust gas purification system for a construction machine according to a first embodiment of the present invention. In FIG. 1, a construction machine (for example, a hydraulic excavator) is equipped with a diesel engine 1. The engine 1 includes an electronic governor 1a that is an electronic fuel injection control device. The target rotational speed of the engine 1 is commanded by the engine control dial 2, and the actual rotational speed of the engine 1 is detected by the rotational speed detection device 3. The command signal of the engine control dial 2 and the detection signal of the rotational speed detection device 3 are input to the controller 4, and the controller 4 controls the electronic governor 1a based on the command signal (target rotational speed) and the detection signal (actual rotational speed). To control the rotational speed and torque of the engine 1.

  The exhaust gas purification system is disposed in an exhaust pipe 31 that constitutes an exhaust system of the engine 1, and includes a filter 32 that collects particulate matter contained in the exhaust gas and an oxidation catalyst 33 that is disposed on the upstream side of the filter 32. A DPF device 34, a differential pressure detection device 36 that detects a differential pressure across the upstream and downstream sides of the filter 32 (pressure loss of the filter 32), an exhaust gas temperature detection device 37, and a regeneration inhibition switch 38 that instructs regeneration inhibition. And a regeneration fuel injection device 39 provided between the engine 1 of the exhaust pipe 31 and the DPF device 34 for increasing the temperature of the exhaust gas. The oxidation catalyst 33 and the regeneration fuel injection device 39 constitute a regeneration device for regenerating the filter 32 by burning and removing PM (particulate matter) deposited on the filter 32.

  The regeneration prohibiting switch 38 is disposed at a position that is easily operated by an operator in the cabin 107 of the excavator, and is a regeneration prohibiting means for instructing prohibition of the operation of the regeneration fuel injection device 39 (prohibition of regeneration of the filter 32). When the regeneration prohibiting switch 38 is operated to the ON position, a command signal for instructing prohibiting regeneration is output. Note that the reproduction prohibition switch 38 may be a setting screen displayed on the display device 6. The operation switch 6b is operated to set ON / OFF.

  The hydraulic excavator includes a hydraulic drive system and an operation pilot system.

  The hydraulic drive system includes a hydraulic pump 11, a control valve 12, and a hydraulic actuator 13. The hydraulic pump 11 is driven to rotate by the engine 1 and discharges pressure oil. The control valve 12 controls the direction and flow rate of the pressure oil and supplies the pressure oil to the hydraulic actuator 13. As a result, the hydraulic actuator 13 is driven. In FIG. 1, only one control valve 12 and one hydraulic actuator 13 are shown for simplicity, but the hydraulic drive system has a plurality of control valves and a plurality of hydraulic actuators.

  The hydraulic pump 11 tilts the hydraulic pump 11 so that the absorption torque (consumption torque) of the hydraulic pump 11 does not exceed a maximum absorption torque that is a predetermined value based on the discharge pressure (the amount of tilt of the swash plate; It has a regulator 11a for controlling the displacement or capacity).

  The operation pilot system includes a pilot pump 16 and an operation device 17. The pilot pump 16 is rotated by the engine 1 to generate a pilot primary pressure. The operation device 17 generates pilot operation pressures PL1 and PL2 based on the operation direction and the operation amount. The pilot operating pressures PL1 and PL2 are applied to the control valve 17, whereby the control valve 12 is switched.

  The hydraulic excavator rotates a hydraulic pump 11 by the engine 1 and drives a hydraulic actuator 13 such as an arm cylinder 115 (described later) by pressure oil discharged from the hydraulic pump 11 to perform necessary work such as excavation.

  FIG. 2 is a diagram illustrating an appearance of the hydraulic excavator. The hydraulic excavator includes a lower traveling body 100, an upper swing body 101, and a front work machine 102. The lower traveling body 100 has left and right crawler traveling devices 103a and 103b, and is driven by left and right traveling motors 104a and 104b. The upper swing body 101 is turnably mounted on the lower traveling body 100 by the swing motor 105, and the front work machine 102 is attached to the front portion of the upper swing body 101 so as to be able to be raised and lowered. The upper swing body 101 includes an engine room 106 and a cabin 107, and the engine 1 is disposed in the engine room 106.

  The front work machine 102 has an articulated structure having a boom 111, an arm 112, and a bucket 113. The boom 111 rotates in the vertical direction by expansion and contraction of the boom cylinder 114. , And the bucket 113 is rotated up and down and back and forth by the expansion and contraction of the bucket cylinder 116.

  The construction machine may be a wheel loader or a wheeled hydraulic excavator.

~control~
FIG. 3 is a diagram showing functional blocks of the controller 4. The controller 4 includes a vehicle body controller 41, an engine controller 42, and a display controller 43, and these controllers are connected to each other via a communication line 44 to constitute a vehicle body network. The command signal of the engine control dial 2 and the command signal of the regeneration prohibiting switch 38 are input to the vehicle body controller 41, and the detection signal of the rotation speed detection device 3 and the detection signal of the differential pressure detection device 36 are input to the engine controller 42.

  The vehicle body controller 41 controls the entire vehicle body such as a hydraulic drive device. The discharge pressure and discharge flow rate of the hydraulic pump 11 are controlled by controlling the regulator 11a and the like of the hydraulic pump 11.

  The engine controller 42 receives a command signal from the engine control dial 2 via the communication line 44, and controls the rotational speed and torque of the engine 1 based on the command signal and a detection signal from the rotational speed detection device 3.

  Further, the engine controller 42 receives the detection signal of the differential pressure detection device 36, estimates the PM accumulation amount, performs regeneration control calculation processing based on the estimated PM accumulation amount, and according to the calculation result, the electronic governor 1a. And the fuel injection device 39 for regeneration is controlled (automatic regeneration control).

  The display controller 43 receives various signals from the rotation speed detection device 3, the differential pressure detection device 36, and the regeneration prohibition switch 38 and the calculation processing result of the forced regeneration control via the communication line 44, and displays them as display signals on the display device 6. The information is sent and displayed on the display screen 6a. In addition, a command signal from the operation switch 6b as a user interface is input.

  FIG. 4 is a flowchart showing the contents of the arithmetic processing by the controller 4. In addition to basic automatic regeneration control arithmetic processing, arithmetic processing related to operation restriction control, which is a characteristic configuration, is shown.

  Here, the first threshold is an automatic regeneration start value, the second threshold is a regeneration end value, the third threshold is a deposition limit value, the fourth threshold is a warning activation value, and the fifth threshold is an operation limit. Operating value.

  It is determined whether or not the PM deposition amount based on the detection signal of the differential pressure detection device 36 is greater than the fourth threshold (step S10). If it is determined that the PM deposition amount is not greater than the fourth threshold, the PM deposition amount is the fourth. The process of step S10 is repeated until it exceeds the threshold. The fourth threshold is set slightly lower than the first threshold. If it is determined in step S10 that the PM accumulation amount is larger than the fourth threshold value, a notice regarding the start of regeneration is made (step S20).

  After the notice, it is determined whether or not the PM accumulation amount is greater than the first threshold (step S30). If it is determined that the PM accumulation amount is not greater than the first threshold, step S20 is performed until the PM accumulation amount is greater than the first threshold. The process of step S30 is repeated.

  If it is determined in step S30 that the PM accumulation amount is greater than the first threshold value, it is determined whether regeneration prohibition is commanded (step S40). If it is determined that regeneration prohibition is not commanded (regeneration is possible), automatic regeneration is performed. Control is started (step S50).

  During automatic regeneration control, it is determined whether regeneration prohibition is commanded (step S60), and if it is determined that regeneration prohibition is not commanded (regeneration is possible), it is determined whether the PM accumulation amount is less than the second threshold value. However, if it is determined that the PM accumulation amount is not smaller than the second threshold value, the processes of steps S60 and S70 are repeated until the regeneration prohibition is instructed or the PM accumulation amount becomes smaller than the second threshold value.

  If it is determined in step S70 that the PM accumulation amount has become smaller than the second threshold, the automatic regeneration control is stopped (step S80), and the calculation process is terminated.

  The automatic regeneration control is performed as follows, for example. First, the rotational speed of the engine 1 is controlled to a predetermined rotational speed Na suitable for forced regeneration control. The predetermined rotation speed Na suitable for the forced regeneration control is a medium speed rotation speed that can raise the temperature of the exhaust gas at that time to a temperature higher than the activation temperature of the oxidation catalyst 33. In this control, the vehicle body controller 41 switches the target rotational speed of the engine 1 from the target rotational speed indicated by the engine control dial 2 to a predetermined rotational speed Na, and the predetermined rotational speed Na (target rotational speed) is changed to the communication line 44. To the engine controller 42. The engine controller 42 feedback-controls the fuel injection amount of the electronic governor 1 a based on the target rotational speed (predetermined rotational speed Na) and the actual rotational speed of the engine 1 detected by the rotational speed detection device 3. Control is performed so that the rotational speed becomes the predetermined rotational speed Na. Further, the load acting on the hydraulic pump 11 may be increased so that the temperature of the exhaust gas is raised to a temperature higher than the activation temperature of the oxidation catalyst 33.

  Next, when it is confirmed that the exhaust gas temperature detected by the exhaust temperature detection device 37 has risen to a predetermined temperature (a temperature higher than the activation temperature of the oxidation catalyst 33), the regeneration fuel injection device 39 is controlled to exhaust the exhaust gas. Fuel is injected into the pipe 31. By injecting fuel into the exhaust pipe 31, unburned fuel is supplied to the oxidation catalyst 33. The unburned fuel is oxidized by the oxidation catalyst 33, and the exhaust gas temperature further rises due to the reaction heat obtained at that time. The PM deposited on the filter 32 is removed by incineration.

  When stopping the regeneration control, the target rotational speed is returned to the target rotational speed (low-speed idle rotational speed) indicated by the engine control dial 2, and the control of the regeneration fuel injection device 39 is stopped. Instead of returning the target rotational speed to the target rotational speed (low-speed idle rotational speed) indicated by the engine control dial 2, the engine 1 may be stopped.

  The operation restriction control that is a feature of this embodiment will be described.

  If it is determined in step S40 that the regeneration prohibition is instructed, it is determined whether the PM accumulation amount is greater than the fifth threshold (step S90), and if it is determined that the PM accumulation amount is not greater than the fifth threshold, the PM accumulation amount. Until the value exceeds the fifth threshold, the process of step S90 is repeated. The fifth threshold is set higher than the first threshold.

  If it is determined in step S60 that the prohibition of regeneration is instructed, automatic regeneration control is stopped (step S80), and the process of step S90 is performed.

  If it is determined in step S90 that the PM accumulation amount is greater than the fifth threshold value, operation restriction control is performed (step S100), and notification that the operation is being restricted is provided (step S110).

  The operation restriction control in step S100 is performed as follows, for example.

  The vehicle body controller 41 switches the target rotational speed of the engine 1 from the target rotational speed indicated by the engine control dial 2 to a lower rotational speed, and transmits the switched target rotational speed to the engine controller 42 via the communication line 44. . The engine controller 42 feedback-controls the fuel injection amount of the electronic governor 1a based on the target rotational speed and the actual rotational speed of the engine 1 detected by the rotational speed detection device 3, and the rotational speed of the engine 1 is controlled by the engine control dial 2. Is controlled so that the rotational speed is lower than the target rotational speed indicated by. As the engine speed decreases, the output of the engine 1 decreases, the pump 11 cannot be driven sufficiently, and the operation of the actuator 13 is restricted.

  Further, the output of the pump 11 may be limited. The vehicle body controller 41 controls the tilt of the regulator 11a, thereby reducing the discharge flow rate of the hydraulic pump 11 and limiting the pump output. Thereby, the operation of the actuator 13 is limited.

  In addition to the engine output limit and the pump output limit, the pilot operating pressures PL1 and PL2 may be reduced. Even if the operating device 17 is operated by a predetermined amount, the desired operation of the actuator 13 cannot be obtained.

  A plurality of these operation restriction means may be combined.

-Correspondence with claims-
In the present embodiment, the differential pressure detection device 36, the display screen 6a, the engine controller 42, the display controller 43, and the processing in steps S10 and S20 in the flowchart constitute warning means for giving a warning regarding regeneration.

  Further, the electronic governor 1a of the engine 1, the regulator 11a, the vehicle body controller 41, the engine controller 42, and the process of step S100 in the flowchart are determined to be greater than the first threshold value in step S30 after warning (notice). However, in the case where it is determined that regeneration prohibition is instructed in step 40 (or step 60) even though regeneration is to be started, an operation restriction means for restricting the operations of the plurality of actuators 13 is configured.

~ Operation ~
The operation of the exhaust gas purification system of this embodiment will be described.

  First, the operation during general work will be described. During general work, the regeneration prohibiting switch 38 is in the OFF position, and automatic regeneration control is appropriately performed. That is, when the PM accumulation amount exceeds the fourth threshold value before the first threshold value, the regeneration start is notified, and when the PM accumulation amount exceeds the first threshold value, automatic regeneration starts, and the accumulated PM is burned and removed. When the amount becomes less than the second threshold, the automatic regeneration stops (S10 → S20 → S30 → S40 → S50 → S60 → S70 → S80). Thereby, DPF breakage can be prevented.

  Here, an indoor work is assumed. FIG. 5 shows an example of the elapsed time of the PM deposition amount shown for assisting understanding. When working indoors, dust and the like are likely to fly, and PM accumulates on the filter. When the regeneration prohibition switch 38 is in the OFF position and the PM accumulation amount exceeds the fourth threshold before the first threshold, the regeneration start is notified, and when the PM accumulation amount exceeds the first threshold, automatic regeneration starts (S10). → S20 → S30 → S40 → S50).

  However, if the operator determines that there is a combustible material in the surrounding area and there is a risk of ignition and operates the regeneration prohibiting switch 38 to the ON position, the automatic regeneration is stopped (S60 → S80). Further, when working indoors, the regeneration prohibiting switch 38 may be operated to the ON position in advance. In this case, even if the PM accumulation amount exceeds the first threshold, automatic regeneration does not start (S10 → S20 → S30 → S40).

  Since there is no risk of ignition due to regeneration, the operator can continue working indoors.

  On the other hand, when the PM accumulation further proceeds due to the prohibition of regeneration and the PM accumulation amount exceeds the fifth threshold value, the operation is restricted and the fact that the operation is restricted is displayed on the display screen 6a (S90 → S100 → S110). . When the operation of the hydraulic excavator is restricted, the work that can be performed by the operator is also restricted. For example, since the driving speed of the actuator decreases, excavation work as usual cannot be performed.

  The notification screen on the display screen 6a includes a recommendation regarding suspension of operation and movement of the hydraulic excavator to an outdoor recyclable place, together with the fact that the operation is being restricted.

  When the operator recognizes that the operation of the hydraulic excavator is being restricted by the notification on the display screen 6a, the operator interrupts the work or completes the minimum work possible even while the operation is restricted, and then presses the hydraulic pressure to an outdoor recyclable place. Move the excavator. In other words, the operation restriction and the notification thereof cause the operator to give up the work continuation and prompt the excavator to move to a recyclable place. Note that low-speed traveling of the hydraulic excavator is one of the possible operations even when the operation is restricted.

  Then, the surrounding safety is confirmed, and the regeneration prohibiting switch 38 is operated to the OFF position. At this time, the PM accumulation amount is larger than the first threshold value, automatic regeneration control is performed, and the accumulated PM is burned and removed (S10 → S20 → S30 → S40 → S50 → S60 → S70 → S80). If automatic regeneration control is not performed, manual regeneration control may be performed.

  At this time, as a result of the operation restriction, the PM emission amount is reduced, the progress of PM deposition is relaxed, and the time until the PM deposition amount reaches the limit value (third threshold value) is extended. The operator can move the excavator to an outdoor recyclable place before the PM accumulation amount reaches the limit value.

  Thereby, it is possible to prevent DPF damage even when regeneration is prohibited.

  After completion of outdoor regeneration, the operator resumes indoor work.

~effect~
The effect of the exhaust gas purification system of this embodiment will be described. In the prior art, if the operation is continued with the regeneration prohibited, PM continues to accumulate, and eventually the PM accumulation amount reaches the limit value (third threshold value), and there is a possibility that the DPF is damaged (FIG. 5 virtual history ( (See dashed line). In this embodiment, by restricting the operation, the operator is given up to continue the work and prompts the excavator to move to a recyclable place. As a result, since reproduction is performed at a reproducible place, DPF damage can be prevented.

At this time, since the fifth threshold value related to the motion restriction is set higher than the first threshold value related to the start of reproduction, the time when the motion restriction is started can be extended, and the indoor working time can be extended. This ensures workability even when regeneration is prohibited.
Second Embodiment
The fifth threshold value related to the operation restriction is set to be not less than the first threshold value related to the start of reproduction and not more than the third threshold value related to the limit value. In the first embodiment, the fifth threshold value is set higher than the first threshold value, but it may be approximately the same (first threshold value = fifth threshold value).

  FIG. 6 is a flowchart showing the contents of the arithmetic processing by the controller 4. The same step number is attached to the same arithmetic processing as in FIG. The difference from the first embodiment is that the calculation process in step S90 is omitted, and the determination relating to the start of the operation restriction control is substituted in step S30.

  FIG. 7 shows an example of the elapsed time of the PM deposition amount.

  When the indoor work is performed, the regeneration prohibiting switch 38 is operated to the ON position in advance. When the PM deposition amount exceeds the first threshold value (= the fifth threshold value), the operation is restricted and a notification that the operation is being restricted is given. (S10-> S20-> S30-> S40-> S100-> S110).

  During automatic regeneration, when the operator determines that there are combustibles in the surrounding area and there is a risk of ignition and operates the regeneration prohibiting switch 38 to the ON position, operation restriction and notification are performed (S10 → S20 → S30). → S40 → S50 → S60 → S100 → S110).

  The effect of the operation restriction is the same as that of the first embodiment.

  In the present embodiment, the above effects can be obtained with simpler control than in the first embodiment.

In addition, since the fifth threshold value is set to be approximately the same as the first threshold value, the time when the operation restriction is started can be advanced compared to the first embodiment. As a result, before a large amount of PM accumulates, regeneration is performed at a recyclable place, so that DPF breakage can be prevented more reliably.
<Third Embodiment>
In the first embodiment, the fourth threshold value for warning (reproduction start notice) is set to be less than the first threshold value, but the fourth threshold value may be set to be equal to or more than the first threshold value and less than the fifth threshold value. For example, the fourth threshold value may be set to the same level as the first threshold value.

  FIG. 8 is a flowchart showing the contents of the arithmetic processing by the controller 4. The same step number is attached to the same arithmetic processing as in FIG. The difference from the first embodiment is that the arithmetic processing in step S10 and step S20 is omitted, the determination relating to the warning is substituted in step S30, and the arithmetic processing in step S85 is further added.

  That is, instead of the warning related to the reproduction start notice (step S20), the reproduction is prohibited even though the reproduction should be started, and the warning that the reproduction cannot be performed and the DPF may be damaged (step S85). I do.

  FIG. 9 shows an example of the elapsed time of the PM deposition amount.

  When the indoor work is performed, the regeneration prohibiting switch 38 is operated to the ON position in advance. When the PM accumulation amount exceeds the first threshold value (= the fourth threshold value), the regeneration starts originally, but the regeneration is prohibited, so the regeneration does not start even if the PM accumulation amount exceeds the first threshold value. Instead, a warning is issued (S30 → S40 → S85). Along with the warning, the operation restriction may be notified in advance.

  During automatic regeneration, a warning is also issued when the operator determines that there are combustibles in the surrounding area and there is a risk of ignition and operates the regeneration prohibiting switch 38 to the ON position (S30 → S40 → S50 → S60 → S85).

  Since there is no risk of ignition due to regeneration, the operator can continue to work indoors. However, if the work is continued even after the warning, the PM accumulation further proceeds, and if the PM accumulation amount exceeds the fifth threshold, the operation restriction and notification are issued. (S90 → S100 → S110).

  The effect of the operation restriction is the same as that of the first embodiment.

  Since the fourth threshold value is set to be approximately the same as the first threshold value, it is possible to extend the warning time as compared to the first embodiment. As a result, the operator can concentrate on the work without being bothered by the warning.

In addition, you may perform the reproduction | regeneration start announcement in 1st and 2nd embodiment collectively.
<Fourth embodiment>
In the first to third embodiments, the operation restriction is started based on the determination whether the PM accumulation amount exceeds the fifth threshold (step S90), but the operation restriction is started when a predetermined time elapses after the warning. As such, an exhaust gas purification system may be configured.

  FIG. 10 is a flowchart showing the contents of the arithmetic processing by the controller 4. The same step numbers are assigned to the same arithmetic processing as in FIG. The difference from the third embodiment is that instead of determining whether the PM accumulation amount has exceeded the fifth threshold (step S90), a determination whether a predetermined time has elapsed after the warning (step S95) is added. It is a point.

  FIG. 11 shows an example of the elapsed time of the PM deposition amount.

  When the indoor work is performed, the regeneration prohibiting switch 38 is operated to the ON position in advance. When the PM accumulation amount exceeds the first threshold value (= fourth threshold value), a warning and an operation restriction advance notice are performed (S30 → S40 → S85). At the time of the operation restriction advance notice, a predetermined time after the warning until the start of the operation restriction may be displayed on the display screen 6a. Furthermore, the time until the start of operation restriction may be updated as needed.

  While the operator can continue working indoors, if the work is continued even after the warning, PM deposition further proceeds, and when a predetermined time has elapsed, operation restriction and notification are performed (S90 → S100 → S110).

By starting the operation restriction based on the determination whether or not a predetermined time has passed after the warning (step S95), the operator can recognize the work continuation possible time after the warning and can work in a planned manner.
<Fifth Embodiment>
Although the first to fourth embodiments have been described on the assumption of automatic regeneration control, the present invention may be applied to manual regeneration control.

  If manual regeneration is not performed even if a predetermined threshold value (for example, the first threshold value) is exceeded, a warning is given to urge manual regeneration, and if the operation is continued after the warning, PM deposition further proceeds, and the amount of PM deposition When the value exceeds the fifth threshold, operation restriction and notification are performed.

  The operator moves the hydraulic excavator to an outdoor recyclable place and performs manual regeneration.

  The effect of the operation restriction is the same as that of the first embodiment.

DESCRIPTION OF SYMBOLS 1 Diesel engine 1a Electronic governor 2 Engine control dial 3 Rotation speed detection apparatus 4 Controller 6 Display apparatus 6a Display screen 6b Operation switch 11 Hydraulic pump 11a Regulator 12 Control valve 13 Hydraulic actuator 16 Pilot pump 17 Operation apparatus 31 Exhaust pipe 32 Filter 33 Oxidation Catalyst 34 DPF device 36 Differential pressure detection device 37 Exhaust temperature detection device 38 Regeneration prohibition switch 39 Regeneration fuel injection device 41 Car body controller 42 Engine controller 43 Display controller 44 Communication line 100 Lower traveling body 101 Upper turning body 102 Front work machine 103a, 103b Crawler type traveling devices 104a, 104b Traveling motor 105 Turning motor 106 Engine room 107 Cabin 108 Driver's seat 111 Boom 112 Arm 113 Packet 114 boom cylinder 115 arm cylinder 116 bucket cylinder

Claims (8)

It is mounted on a construction machine equipped with a diesel engine and a plurality of driven bodies driven by the power of this engine,
A filter disposed in the exhaust system of the engine for collecting particulate matter contained in the exhaust gas;
A regenerator that incinerates and removes particulate matter deposited on the filter and regenerates the filter;
An exhaust gas purification system comprising: a regeneration control device that instructs start and stop of the operation of the regeneration device; and regeneration prohibiting means that prohibits the operation of the regeneration device.
Warning means to give a warning about playback,
After the warning means is activated, the operation of the plurality of driven bodies is performed when the regeneration prohibiting means prohibits the operation of the reproducing apparatus even though the regeneration control apparatus gives an instruction to start the operation of the reproducing apparatus. An exhaust gas purification system comprising: an operation restricting means for restricting the exhaust gas. The exhaust gas purification system according to claim 1,
A deposition amount estimating means for estimating a deposition amount of the particulate matter deposited on the filter;
When the estimated accumulation amount exceeds the first threshold, the regeneration control device instructs the regeneration device to start operation,
The exhaust gas purification system according to claim 1, wherein when the estimated accumulation amount exceeds a fourth threshold value which is less than the first threshold value, a regeneration start notice is performed. The exhaust gas purification system according to claim 1,
A deposition amount estimating means for estimating a deposition amount of the particulate matter deposited on the filter;
When the estimated accumulation amount exceeds the first threshold, the regeneration control device instructs the regeneration device to start operation,
The exhaust gas purification system characterized in that the warning means issues a warning to urge regeneration when the estimated accumulation amount exceeds a fourth threshold value that is equal to or greater than a first threshold value. The exhaust gas purification system according to claim 1,
The exhaust gas purification system, wherein the operation limiting means is activated when an estimated accumulation amount exceeds a fifth threshold value that is equal to or greater than a first threshold value. The exhaust gas purification system according to claim 1,
The exhaust gas purification system, wherein the operation restricting means is activated when a predetermined time elapses after the warning means is activated. The exhaust gas purification system according to claim 1,
The exhaust gas purification system characterized in that the operation limiting means limits engine output. The exhaust gas purification system for a construction machine according to claim 1,
The construction machine further includes a hydraulic circuit including a hydraulic pump driven by the engine and a hydraulic actuator driven by the discharge oil of the hydraulic pump to drive the driven body,
The exhaust gas purification system, wherein the operation limiting means limits a pump output of the hydraulic pump. The exhaust gas purification system for a construction machine according to claim 1,
An exhaust gas purification system comprising: an informing means for informing that the operation is being restricted when the operation restricting means is activated.

Images