JP2010270699A - Exhaust emission control device for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for a construction machine capable of avoiding danger following regeneration during the absence of a driver. <P>SOLUTION: When the driver stands up from a driver's seat 108 to leave a hydraulic shovel, in a controller 4, a detection signal of a pressure equal to almost zero is inputted from a pressure detection sensor 51, and the absence of the driver is detected. When the absence of the driver passes for a predetermined time, regeneration is stopped. When the driver is seated in the driver's seat 108, in the controller 4, a detection signal of pressure generated by the self-weight of the driver is inputted from the pressure detection sensor 51, the presence of the driver is detected, regeneration is continued until the passage of a predetermined regeneration time, and the regeneration is stopped after the passage of the predetermined regeneration time. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust gas purification apparatus for construction machinery, 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 emission control device for a construction machine that regenerates a filter.

  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. In response to such regulations, an exhaust purification device is known that collects PM with a filter called a diesel particulate filter (DPF) and reduces the amount of PM discharged to the outside. In this exhaust purification device, if the amount of PM accumulated on the filter increases as a result of collection, the filter will become clogged, which will increase the exhaust pressure of the engine and induce deterioration of fuel consumption. The PM accumulated on the filter 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 Therefore, there is a technique called forced regeneration in which the exhaust gas temperature is forcibly raised to a temperature higher than the activation temperature of the oxidation catalyst. 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, as a condition for starting these forced regenerations, the PM accumulation amount (collection amount) of the filter is estimated, and regeneration is performed when the PM accumulation amount reaches a preset PM accumulation limit value. ing. In this case, it is common to detect the differential pressure before and after the filter and calculate the PM deposition amount based on the detected value of the differential pressure. The forced regeneration of the filter includes automatic regeneration that automatically starts regeneration and manual regeneration that starts regeneration by a driver's operation input.

  In the automatic regeneration, the control unit of the exhaust purification apparatus inputs an acquisition signal of the PM accumulation amount, and outputs a command signal for starting regeneration when it is determined that the PM accumulation amount exceeds the threshold value. As a result, the exhaust purification device automatically starts regeneration, and stops regeneration when it is determined that a predetermined time has elapsed or the PM accumulation amount has become a predetermined value or less due to incineration removal.

  However, the exhaust gas temperature does not become higher than the activation temperature in cold districts, the engine stops in the middle of automatic regeneration, or PM cannot accumulate well even if automatic regeneration is performed depending on the usage situation, and PM accumulates In some cases. In such a case, a technique for performing manual regeneration in which regeneration is started by a driver's operation input has been proposed (Patent Documents 1 and 2). In manual regeneration, the control unit of the exhaust gas purification apparatus inputs an acquisition signal of the PM accumulation amount, and outputs a warning signal for prompting regeneration when it is determined that the PM accumulation amount exceeds a threshold value. The driver operates the regeneration switch while watching the warning display. The control unit of the exhaust gas purification apparatus inputs an operation signal and outputs a command signal for starting regeneration.

  Such manual regeneration can be performed during work, but is often performed while the construction machine is not working, that is, during engine idling. However, during engine idling, the temperature and flow rate of the exhaust gas is too low, and it is difficult to satisfactorily remove PM by combustion. For this reason, the exhaust emission control device described in Patent Document 1 includes a control device that automatically increases the engine speed when manual regeneration is performed during engine idling. Moreover, the exhaust emission control device described in Patent Document 2 includes an exhaust throttle valve that closes when manual regeneration is performed during engine idling. Thereby, the exhaust emission control device of the prior art can perform good PM combustion removal even when the engine is idling. Patent Document 2 points out that it is preferable to perform regeneration during engine idling from the viewpoint of reducing oil dilution. Although automatic regeneration may also be performed during engine idling, these conventional techniques can similarly perform good PM combustion removal.

JP 2003-155914 A JP 2005-282545 A

  However, the above prior art has the following problems.

  As described above, the exhaust gas in the DPF is hot. When the exhaust purification device is mounted on an automobile or truck, the exhaust gas can be discharged after being cooled to a safe temperature by providing a sufficiently long exhaust pipe. However, a construction machine such as a hydraulic excavator cannot be provided with a sufficiently long exhaust pipe for the convenience of vehicle body layout, and may exhaust exhaust gas at a high temperature.

  In general, engine idle occurs when the work of a construction machine is suspended. When the operator of the construction machine sees the warning message for manual regeneration, he / she may move away from the construction machine to operate the regeneration switch and then take a rest at the dump during manual regeneration. If there are combustible materials around the construction machine, high temperature exhaust gas can ignite the combustible materials and cause a fire. However, if the driver is away from the construction machine during regeneration, it will not be possible to deal with unexpected situations.

  The conventional techniques described in Patent Documents 1 and 2 are techniques that can perform good PM combustion removal even when regeneration is performed during engine idling, but the driver is away from the construction machine. It is not taken into account, and the risks associated with regeneration in the absence of the driver cannot be avoided.

  An object of the present invention is to provide an exhaust emission control device for a construction machine that can avoid a danger associated with regeneration in the absence of a driver.

  (1) In order to achieve the above object, the present invention provides a filter that is disposed in an exhaust system of an engine and collects particulate matter contained in exhaust gas, and removes the particulate matter deposited on the filter by incineration. Then, in an exhaust emission control device for a construction machine comprising a regenerator that regenerates the filter and a regenerative control device that controls the start / stop of the operation of the regenerator, the presence or absence of a driver in the cab of the construction machine is detected. Driver detection means is provided, and the regeneration control device has a function of stopping the operation of the regeneration device when the driver detection means detects the absence of the driver during regeneration.

  When the driver detecting means detects the absence of the driver during regeneration, the driver detecting means detects the absence of the driver during the regeneration, and the regeneration device is stopped so that if the driver is absent, the hot exhaust gas due to the regeneration is discharged. No accidents such as ignition will occur. On the other hand, when the driver detection means detects the presence of the driver during the regeneration, the regeneration is performed. Even if an unforeseen event such as ignition occurs, the driver is in the cab of the construction machine and can immediately take appropriate measures such as extinguishing the fire. As a result, it is possible to avoid the danger associated with regeneration in the absence of the driver.

  (2) In the above (1), preferably, the system further comprises driver absent time measuring means for measuring the driver absent time detected by the driver detecting means, and the regeneration control device is configured to measure the driver absent time. When the driver's absence time measured by the means elapses for a predetermined time, it has a function of stopping the operation of the regeneration device.

  When the driver changes his driving posture for some reason, the driver detection means may mistakenly recognize that the driver is absent even though the driver is in the driver's cab. Thus, by further providing the driver absent time measuring means, such misidentification can be prevented, and the driver detecting means can reliably detect the absence of the driver.

  (3) In the above (1) or (2), preferably, the driver detection means is provided in a driver's seat in the driver's cab and detects pressure by a driver seated in the driver's seat. It has a detection means.

  As a result, the driver detection means can reliably detect the absence of the driver.

  (4) In the above (1) or (2), preferably, the driver detecting means is provided in a driver seat in the driver's cab, and a contact point of a safety belt worn by a driver seated in the driver seat. Has a switch.

  As a result, the driver detection means can reliably detect the absence of the driver.

  (5) In the above (1) or (2), preferably, the driver detection means includes an infrared device having an infrared transmission unit and an infrared reception unit provided corresponding to the driver seat.

  As a result, the driver detection means can reliably detect the absence of the driver.

  (6) In the above (1) or (2), preferably, the driver detecting means includes a transmitter provided in a key for starting the construction machine and a receiver for receiving a signal of the transmitter. And have.

  As a result, the driver detection means can reliably detect the absence of the driver. Even if the driver is not in the driver's cab, the driver detection means can detect a state in accordance with the driver's occupancy if the driver is in the vicinity of the construction machine.

  According to the present invention, it is possible to avoid a risk associated with regeneration in the absence of a driver.

1 is a diagram showing an exhaust emission control apparatus according to an embodiment of the present invention together with an overall system configuration. It is a figure which shows the processing content of a controller. It is a flowchart which shows the processing content of the reproduction | regeneration control part when performing manual reproduction | regeneration. It is a flowchart which shows the processing content of the reproduction | regeneration control part when performing automatic reproduction | regeneration. It is a figure which shows the external appearance of a hydraulic shovel. It is a flowchart which shows the processing content of the reproduction | regeneration control part when performing automatic reproduction | regeneration in a modification.

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

~Constitution~
FIG. 1 is a diagram showing an exhaust purification apparatus according to an embodiment of the present invention together with the entire system configuration.

  FIG. 2 is a diagram showing the processing contents of the controller 4 shown in FIG. The controller 4 includes an engine control unit 41, a regeneration control unit 42, a driver detection unit 43, and a driver absent time measurement unit 44.

  The exhaust purification device of this embodiment is mounted on a construction machine (for example, a hydraulic excavator). The hydraulic excavator is equipped with a diesel engine 1, and the engine 1 includes an electronic governor 1a which 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 engine control unit 41 (FIG. 2) of the controller 4 receives the command signal (target rotational speed) and the detection signal (actual rotational speed). ) To control the electronic governor 1a and to control the rotation speed and torque of the engine 1. A key switch 5 is provided as a start / stop command device for the engine 1, and a command signal for the key switch 5 is also input to the controller 4. The engine control unit 41 of the controller 4 starts the engine 1 based on the ON / OFF signal. And control stop.

  The exhaust purification device 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 exhaust gas and an oxidation catalyst 33 that is disposed upstream of the filter 32. A device 34, a differential pressure detection device 36 for detecting a differential pressure across the upstream and downstream sides of the filter 32 (pressure loss of the filter 32), and an exhaust temperature that is installed upstream of the filter and detects the temperature of the exhaust gas. A detection device 37, a regeneration switch 38, a regeneration fuel injection device 39 provided between the engine 1 of the exhaust pipe 31 and the DPF device 34, and a regeneration control unit 42 which is a function of the controller 4 (FIG. 2). And.

  The regeneration control unit 42 of the controller 4 inputs detection signals of the differential pressure detection device 36 and the exhaust temperature detection device 37, and based on those input signals and the input signals from the rotation speed detection device 3 and the key switch 5 described above. Filter regeneration calculation processing is performed, and the electronic governor 1a and the regeneration fuel injection device 39 are controlled according to the calculation result. Further, the regeneration control unit 42 of the controller 4 displays information indicated by various signals of the rotation speed detection device 3, the key switch 5, the differential pressure detection device 36, and the exhaust gas temperature detection device 37 and information on the result of the filter regeneration calculation processing of the controller 4. The information is sent to the display device 6 as a display signal, and the information is displayed on the display screen of the display device 6. The display device 6 is installed in a cab 107 of a hydraulic excavator.

  Here, filter regeneration will be described. Filter regeneration includes automatic regeneration that automatically starts regeneration and manual regeneration that starts regeneration by a driver's operation input. As a result of collection, the differential pressure across the filter 32 increases as the amount of PM deposited on the filter 32 increases. The controller 4 estimates the PM accumulation amount of the filter from the differential pressure before and after the filter detected by the differential pressure detection device 36. In automatic regeneration, when it is determined that the PM accumulation amount has exceeded the first threshold value, a command signal for starting regeneration. Is output to the regeneration fuel injection device 39.

  The regeneration fuel injection device 39 performs fuel injection (preliminary injection) aimed at increasing the exhaust gas temperature, and then confirms that the exhaust gas temperature detected by the exhaust temperature detection device 37 has risen to a predetermined temperature. Fuel injection (main injection) aimed at PM combustion is performed. The fuel injection aiming at raising the exhaust gas temperature is to inject the fuel into the exhaust pipe 31 to burn the fuel by the heat of the exhaust gas passing through the exhaust pipe, so that the temperature of the exhaust gas is higher than the activation temperature of the oxidation catalyst 33 This is to increase the temperature to a high temperature and is an injection for performing forced regeneration. Fuel injection intended for PM combustion is obtained by injecting fuel into the exhaust pipe 31 to supply unburned fuel to the oxidation catalyst 33 in the exhaust pipe and oxidizing the unburned fuel with the oxidation catalyst 33. The reaction heat is sent to the filter 32, and PM deposited on the filter 32 is removed by incineration.

  However, depending on the usage situation, even if automatic regeneration is performed, PM may be deposited because it cannot be burned and removed well. In such a case, the manual regeneration that starts the regeneration by the driver's operation input is performed. In manual regeneration, when the controller 4 determines that the PM accumulation amount has exceeded the second threshold value, the controller 4 outputs a warning signal for prompting regeneration to the display device 6. The driver operates the regeneration switch 38 while watching the warning display displayed on the display device 6. The controller 4 inputs an operation signal and outputs a command signal for starting regeneration to the regeneration fuel injection device 39. Note that the second threshold value is set higher than the first threshold value so that automatic reproduction is preferentially performed.

  In both automatic regeneration and manual regeneration, when the controller 4 determines that a predetermined regeneration time has elapsed, it outputs a command signal for stopping regeneration to the regeneration fuel injection device 39.

  The exhaust emission control device according to the present embodiment includes, as a characteristic configuration, a pressure detection sensor 51 that constitutes a driver detection unit, a driver detection unit 43 (FIG. 2) of the controller 4, and a driver absence time measurement unit. A driver absence time measuring unit 44 (FIG. 2) of the controller 4 is provided. The pressure detection sensor 51 is provided inside the driver's seat 108 in the driver's cab 107 and detects pressure due to the driver's own weight seated on the driver's seat 108.

  The driver detection unit 43 of the controller 4 receives the detection signal of the pressure detection sensor 51 and detects the presence or absence of the driver in the cab 107 based on this detection signal. The driver absent time measuring unit 44 of the controller 4 measures the driver absent time detected by the driver detecting unit 43. Then, the regeneration control unit 42 of the controller 4 detects the absence of the driver during the reproduction by the driver detection unit 43, and when the driver absence time measured by the driver absence time measurement unit 44 has elapsed for a predetermined time, the regeneration is performed. A stop command signal is output to the regeneration fuel injection device 39.

  FIG. 3 is a flowchart showing the processing contents of the regeneration control unit 42 when performing manual regeneration.

  In FIG. 3, the regeneration control unit 42 receives a detection signal from the differential pressure detection device 36 (step S1), and whether or not the differential pressure ΔP across the filter 32 indicated by the detection signal exceeds the manual regeneration start determination value ΔP2. That is, it is determined whether or not ΔP> ΔP2 is satisfied (step S2). If ΔP> ΔP2 is not satisfied, the process returns to step S1, and the processing of steps S1 and S2 is repeated. If ΔP> ΔP2, it is determined that PM has accumulated in the filter 32 beyond the second threshold value, and a warning prompting regeneration is performed. A signal is output to the display device 6 (step S3).

  Here, the manual regeneration start determination value ΔP2 is a differential pressure before and after the PM accumulation amount corresponding to the second threshold value. That is, when PM is not accumulated on the filter 32, there is no differential pressure before and after due to the effect of the accumulated PM, the differential pressure ΔP increases as PM accumulates on the filter 32, and the differential pressure ΔP becomes the regeneration start determination value ΔP2. It is determined that the PM accumulation amount has reached the second threshold value that requires manual regeneration.

  The driver operates the regeneration switch 38 while watching the warning display displayed on the display device 6. The regeneration control unit 42 receives an operation signal from the regeneration switch 38 (step S4), and outputs a command for controlling the engine 1 to a predetermined engine speed Na suitable for regeneration to the engine controller 41 (step S5). Then, a command signal for starting regeneration is output to the regeneration fuel injection device 39 (step S6).

  Here, in the control of the engine speed according to step S5, the target speed of the engine 1 is changed from the target speed indicated by the engine control dial 2 to a predetermined speed Na suitable for forced regeneration higher than the low speed idle speed. The fuel injection amount of the electronic governor 1a is feedback-controlled based on the predetermined rotational speed Na 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 set to the predetermined rotational speed. Control to be Na. The predetermined rotation speed Na suitable for forced regeneration is a 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, for example, a medium speed rotation speed of about 1800 rpm. It is.

  Next, the regeneration control unit 42 determines whether or not the driver is in the cab 107 based on the detection result of the driver detection unit 43 (step S7). The driver detection unit 43 receives a detection signal from the pressure detection sensor 51, detects the driver's occupancy when the pressure is equal to or higher than a predetermined pressure value, and detects the absence of the driver when the pressure is lower than the predetermined pressure value.

  If it is determined in step S7 that the driver is in the cab 107, it is determined whether a predetermined regeneration time has elapsed since the start of regeneration (step S8), and it is determined that the predetermined regeneration time has not elapsed. If so, the processes in steps S7 and S8 are repeated and the reproduction is continued. If it is determined in step S8 that a predetermined regeneration time has elapsed from the start of regeneration, a command signal for stopping regeneration is output to the regeneration fuel injection device 39 (step S9).

  If it is determined in step S8 that the driver is absent from the driver's cab 107, it is determined based on the measurement result of the driver absent time measuring unit 44 whether or not a predetermined driver absent time has elapsed (step S10). If it is determined that the predetermined driver absence time has elapsed, a command signal for stopping regeneration is output to the regeneration fuel injection device 39 (step S9). If it is determined that the predetermined driver absence time has not elapsed, the process proceeds to step S8.

  FIG. 4 is a flowchart showing the processing contents of the playback control unit 42 when performing automatic playback.

  In FIG. 4, the regeneration control unit 42 inputs a detection signal from the differential pressure detection device 36 (step S11), and whether or not the differential pressure ΔP across the filter 32 indicated by the detection signal exceeds the automatic regeneration start determination value ΔP1. That is, it is determined whether or not ΔP> ΔP1 (step S12). If ΔP> ΔP1 is not satisfied, the process returns to step S11, and the processes in steps S11 and S12 are repeated. If ΔP> ΔP1, it is determined that PM has accumulated in the filter 32 beyond the first threshold, and the engine 1 rotates. A command for controlling the number to a predetermined rotational speed Na suitable for regeneration is output to the engine control unit 41 (step S15), and a command signal for starting regeneration is output to the regeneration fuel injection device 39 (step S16). Here, the automatic regeneration start determination value ΔP1 is a differential pressure before and after the PM accumulation amount corresponding to the first threshold value. Note that ΔP2 is set higher than ΔP1 so that automatic reproduction is preferentially performed.

  Next, the regeneration control unit 42 determines whether the driver is in the driver's cab 107 or not based on the detection result of the driver detector 43 (step S17). The driver detection unit 43 receives a detection signal from the pressure detection sensor 51, detects the driver's occupancy when the pressure is equal to or higher than a predetermined pressure value, and detects the absence of the driver when the pressure is lower than the predetermined pressure value.

  If it is determined in step S17 that the driver is in the cab 107, it is determined whether or not a predetermined regeneration time has elapsed since the start of regeneration (step S18), and it is determined that the predetermined regeneration time has not elapsed. If so, the processes in steps S17 and S18 are repeated and the reproduction is continued. If it is determined in step S18 that a predetermined regeneration time has elapsed from the start of regeneration, a command signal for stopping regeneration is output to the regeneration fuel injection device 39 (step S19).

  If it is determined in step S18 that the driver is absent from the driver's cab 107, it is determined whether or not a predetermined driver absent time has elapsed based on the measurement result of the driver absent time measuring unit 44 (step S20). If it is determined that the predetermined driver absence time has elapsed, a command signal for stopping the regeneration is output to the regeneration fuel injection device 39 (step S19). If it is determined that the predetermined driver absence time has not elapsed, the process proceeds to step S18.

  FIG. 5 is a diagram illustrating an appearance of a hydraulic excavator that is an example of a construction machine on which the exhaust emission control device according to the present embodiment is mounted. 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 is provided with an engine room 106 and a cab 107, the engine 1 is disposed in the engine room 106, and a driver seat 108 is provided in the cab 107.

  In the above, among the processing functions of the regeneration control unit 42 of the controller 4, the processing functions of steps S6, S9, S16, and S19 constitute a regeneration control device that controls the start / stop of the operation of the fuel injection device 39 for regeneration. The pressure detection sensor 51 and the driver detection unit 43 of the controller 4 constitute driver detection means for detecting the presence or absence of a driver in the cab 108. Of the processing functions of the regeneration control unit 42 of the controller 4, step S7 , S9, S17, S19 constitutes a function to stop the operation of the regeneration fuel injection device 39 when the driver detection unit 43 detects the absence of the driver during the regeneration.

  The driver absent time measuring unit 44 of the controller 4 constitutes driver absent time measuring means for measuring the driver absent time detected by the driver detecting unit 43, and among the processing functions of the regeneration control unit 42 of the controller 4. The processing functions of steps S9, S10, S19, and S20 constitute a function of stopping the operation of the regeneration fuel injection device 39 when the driver absence time measured by the driver absence time measuring unit 44 has elapsed for a predetermined time.

~ Operation ~
The operation of this embodiment configured as described above will be described.

  First, a case where manual regeneration is performed will be described. While the operation by the hydraulic excavator is continued, PM gradually accumulates, and when the PM accumulation amount exceeds the second threshold, a warning display is displayed on the display device 6 (steps S1 → S2 → S3). When the driver of the hydraulic excavator sees a warning message for manual regeneration, the driver stops the operation and operates the regeneration switch 38 (step S4). By the way, the hydraulic excavator is subjected to auto idle control when not in operation. The auto idle control is a control that automatically reduces the rotational speed of the engine 1 to a low idle speed when the non-working state continues for a predetermined time (for example, about 10 seconds). Therefore, the controller 4 switches the engine speed from the low speed idle speed to a predetermined speed Na suitable for forced regeneration higher than the low speed idle speed, and starts manual regeneration (steps S5 → S6).

  At this time, since the driver takes a rest at the filling station during the manual regeneration, there is a possibility that the driver is separated from the hydraulic excavator. If there are combustible materials around the excavator, the high temperature exhaust gas may ignite the combustible materials and cause a fire. If the driver is away from the excavator during regeneration, it will not be possible to deal with unexpected situations.

  When the driver stands away from the driver's seat 108 to leave the hydraulic excavator, the controller 4 inputs a detection signal of a pressure substantially equal to zero from the pressure detection sensor 51 to detect the absence of the driver. Further, when the driver's absence has elapsed for a predetermined time, the controller 4 reliably detects the absence of the driver without misidentification and stops the regeneration (steps S7 → S10 → S9). Thus, if the driver is absent, the high-temperature exhaust gas due to regeneration is not discharged, and an unexpected situation such as ignition does not occur.

  If the driver is seated on the driver's seat 108, the controller 4 inputs a pressure detection signal based on the driver's own weight from the pressure detection sensor 51, detects the driver's occupancy, and a predetermined regeneration time elapses. The reproduction is continued until the predetermined reproduction time has elapsed, and the reproduction is stopped (steps S7 → S8 → S9). As a result, even if an unexpected situation such as ignition occurs during regeneration, the driver can immediately take appropriate measures such as fire extinguishing because the driver is in the cab 107 of the hydraulic excavator.

  Thereby, the danger accompanying the reproduction | regeneration in the absence of a driver | operator can be avoided.

  When the driver floats to change his driving posture, the controller 4 inputs a pressure detection signal substantially equal to zero from the pressure detection sensor 51 even though the driver is in the driver's cab 107. However, there is a possibility of misidentifying that the driver is absent. However, if the driver is seated again in the driver's seat 108 before the predetermined time has elapsed, it is assumed that the driver is absent (driver's occupancy), and the regeneration is continued (steps S7 → S10 → S8).

  Misidentifying that the driver is absent and stopping the regeneration unnecessarily is not preferable because it causes damage to the DPF device 34. By preventing such misperception and continuing regeneration, PM can be burned and removed well.

  Next, a case where automatic reproduction is performed will be described. While the work with the hydraulic excavator is continued, PM gradually accumulates, and when the PM accumulation amount exceeds the first threshold, the controller 4 is suitable for forced regeneration from the target rotational speed indicated by the engine control dial 2. Then, the automatic regeneration is started by switching to the predetermined rotation number Na (steps S11 → S12 → S15 → S16).

  During automatic regeneration, there is a possibility that the driver will leave the excavator because he / she takes a rest at the filling station.

  Also in the case of performing automatic regeneration, as in the case of performing manual regeneration, the controller 4 stops the regeneration if the driver is absent (steps S17 → S20 → S19), and if the driver is in the room, the predetermined regeneration time. The reproduction is continued until it elapses, and the reproduction is stopped after a predetermined reproduction time has elapsed (steps S17 → S18 → S19). Thereby, the danger accompanying the reproduction | regeneration in the absence of a driver | operator can be avoided.

  In addition, since the driver stops working and takes a rest at the packing station, the PM accumulation amount exceeds the first threshold and the controller 4 performs automatic regeneration when the engine is running and away from the hydraulic excavator. May start. At this time, since the hydraulic excavator is subjected to auto idle control, the engine speed is switched from the low speed idle speed to a predetermined speed Na suitable for forced regeneration (steps S11 → S12 → S15 → S16). At this time, if there is a combustible material around the excavator, the high temperature exhaust gas may ignite the combustible material and cause a fire. If the driver is away from the excavator during regeneration, it will not be possible to deal with unexpected situations.

  If the driver is absent, the controller 4 inputs a pressure detection signal substantially equal to zero from the pressure detection sensor 51 to detect the absence of the driver. Furthermore, when the driver's absence has elapsed for a predetermined time, the controller 4 reliably detects the absence of the driver without misidentification and stops the regeneration (steps S17 → S20 → S19). Actually, since the controller 4 performs the processes of steps S15 → S16 → S17 → S20 → S19 almost simultaneously, if the driver is absent, the reproduction is not substantially started. Thus, if the driver is absent, the high-temperature exhaust gas due to regeneration is not discharged, and an unexpected situation such as ignition does not occur.

~effect~
According to the present embodiment configured as described above, the following effects can be obtained.

  The controller 4 inputs a pressure detection signal based on the driver's own weight from the pressure detection sensor 51, and can detect the presence or absence of the driver in the cab 107 based on the detection signal.

  If the driver is absent, the controller 4 stops the regeneration or does not start the regeneration. Therefore, the high-temperature exhaust gas due to the regeneration is not discharged, and an unexpected situation such as ignition does not occur.

  On the other hand, if the driver is in the room, the regeneration is continued until the predetermined regeneration time has elapsed, and the regeneration is stopped after the predetermined regeneration time has elapsed. Even if an unforeseen event such as ignition occurs during regeneration, the driver is in the cab 107 of the hydraulic excavator and can immediately take appropriate measures such as extinguishing the fire.

  Thereby, the danger accompanying the reproduction | regeneration in the absence of a driver | operator can be avoided.

~ Modification ~
Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made within the spirit of the present invention. The modifications are listed below.

  1. In the embodiment described above, in order to prevent the driver detection unit 43 from misidentifying that the driver is absent, even if the driver is in the driver's cab 107 due to the driver's change of driving attitude, Although the processing function (steps S9 and S19) of the absence time measuring unit 44 and the reproduction control unit 42 is provided, these configurations are not essential and may be omitted in order to achieve the object of the present invention.

  In this case, when the driver detection unit 43 detects the absence of the driver during the regeneration, the regeneration control unit 42 of the controller 4 immediately outputs a command signal for stopping the regeneration to the regeneration fuel injection device 39. Thereby, if the driver is absent, the controller 4 can stop the regeneration.

  2. In the above embodiment, the driver detection means for detecting the presence or absence of the driver in the driver's cab 108 is composed of the pressure detection sensor 51 and the driver detection unit 43 of the controller 4. Also good. For example, the safety belt contact switch 52 and the driver detection unit 43 provided by the driver's seat 108 and operated by the driver sitting on the driver's seat 108 may be used.

  The contact switch 52 outputs a contact signal to the controller 4 according to the attachment / detachment of the safety belt. The driver detection unit 43 detects the presence or absence of a driver in the cab 107 based on this contact signal. That is, when the driver wears a safety belt and inputs a contact ON signal, the driver's presence is detected, and when the driver removes the safety belt and inputs a contact OFF signal, the absence of the driver is detected. Thus, the presence or absence of the driver can be detected. Also, a current ON / OFF signal may be used instead of the contact ON / OFF signal. When a current is passed through the contact portion of the safety belt and the driver wears the safety belt, a current ON signal is output to the controller 4. When the driver removes the safety belt, a contact ON signal is output to the controller 4.

  3. The driver detection means may be configured by an infrared device having an infrared transmission unit 53 and an infrared reception unit 54 provided corresponding to the driver's seat 108 and a driver detection unit 43.

  The infrared transmission unit 53 is provided in the cab 107 and in front of the driver's seat 108, and transmits infrared rays. The infrared receiver 54 is provided inside the driver's seat 108 and receives infrared rays when the driver is not present. However, if the driver is present, the infrared rays are blocked and cannot be received. The infrared receiver 54 outputs an infrared detection signal / non-detection signal to the controller 4 in accordance with the presence / absence of infrared reception. The driver detection unit 43 detects the presence or absence of a driver in the cab 107 based on the detection signal / non-detection signal. That is, when the driver sits on the driver's seat 108 and inputs a non-detection signal, the driver's occupancy is detected, and when the driver leaves the driver's seat 108 and inputs a detection signal, the absence of the driver is detected. . Thus, the presence or absence of the driver can be detected.

  4). The driver detection means may include a transmitter 57 provided on the key 56 for starting the hydraulic excavator, a receiver 58 that receives a signal from the transmitter 57, and a driver detection unit 43.

  The key 56 is a so-called smart key that can be locked and unlocked without inserting the key 56 into the keyhole of the door of the cab 107, and the engine 1 can be started without inserting the key 56 into the key switch 5. it can. The receiver 58 receives a signal from the transmitter 57 if the transmitter 57 is less than a certain distance, but cannot receive a signal if the transmitter 57 is more than a certain distance away. The receiver 58 outputs a detection signal / non-detection signal to the controller 4 according to the presence / absence of signal reception. The driver detection unit 43 detects the presence or absence of a driver near the hydraulic excavator based on the detection signal / non-detection signal. In other words, when the driver is in the vicinity of the excavator and a detection signal is input, a state corresponding to the driver's occupancy is detected, and when the driver is far away from the excavator and inputs an undetected signal, the absence of the driver Is detected. Thus, the presence or absence of the driver can be detected.

  In the above embodiment and Modifications 2 and 3, when the driver goes out of the cab 107, the controller 4 detects the absence of the driver even though the driver is in the vicinity of the excavator and can cope with an unexpected situation. , Stop playing. Stopping the regeneration unnecessarily causes damage to the DPF device 34 and is not preferable. In this modified example, even if the driver goes out of the driver's cab 107, if the driver 4 is in the vicinity of the hydraulic excavator, the controller 4 detects a state according to the driver's occupant and continues the regeneration. Thereby, PM can be burned and removed satisfactorily.

  5. In the above embodiment and Modifications 2 to 4, the driver detection means includes a pressure detection sensor 51, a contact switch 52, an infrared device having an infrared transmitter 53 and an infrared receiver 54, and a transmitter 57 provided on the key 56. One of the receivers 58 is included, but a plurality of these may be combined. For example, the driver detection unit 43 detects the absence of the driver when a detection signal less than a predetermined pressure value is input from the pressure detection sensor 51 and a contact OFF signal is input from the contact switch 52. Thus, the presence or absence of the driver can be detected more reliably.

  6). In the above embodiment, if there is a possibility of performing automatic regeneration while the driver is absent, the controller 4 can perform steps S15 → S16 → S17 → S20 → S19 almost simultaneously, so that the driver is absent. For example, although control is performed so that the reproduction is not substantially started, a process equivalent to the process of step S17 → S20 may be performed before the process (step S15 → S16) until the automatic reproduction is started.

  FIG. 6 is a flowchart showing the processing contents of the playback control unit 42 when automatic playback is performed. Processes equivalent to those in FIG. 4 are denoted by the same reference numerals, and processes equivalent to those in steps S17 → S20 (steps S27 → S30) are added before the processes up to the start of automatic reproduction (steps S15 → S16). is doing.

  In this case, if there is a possibility that the PM accumulation amount exceeds the first threshold value in the absence of the driver (step S11 → S12) and automatic regeneration is performed, the controller 4 detects the pressure almost equal to zero from the pressure detection sensor 51. A signal is input to detect the absence of the driver, and when the driver is absent for a predetermined time, the pressure difference across the filter 32 is detected again without starting automatic regeneration (steps S27 → S30 → S11).

  This process is repeated until the driver is seated again on the driver's seat 108 (steps S11 → S12 → S27 → S30 → S11). When the driver is seated again on the driver's seat 108, automatic regeneration is started. (Steps S11 → S12 → S27 → S15 → S16 → S17 → S18 → S19). Thereby, the effect similar to the said embodiment is acquired.

  7). In the above embodiment, the controller 4 controls to stop the regeneration when a predetermined regeneration time elapses. However, the controller 4 may control to stop the regeneration when the PM accumulation amount becomes the third threshold value or less. The third threshold value is a value at which it can be considered that PM has been successfully burned and removed by regeneration.

DESCRIPTION OF SYMBOLS 1 Diesel engine 1a Electronic governor 2 Engine control dial 3 Rotation speed detection device 4 Controller 5 Key switch 6 Display device 11 Reference setting part 12 First calculation part 13 Storage part 14 Second calculation part 15 Third calculation part 31 Exhaust pipe 32 Filter 33 Oxidation catalyst 34 DPF device 36 Differential pressure detection device 37 Exhaust temperature detection device 38 Regeneration switch 39 Regeneration fuel injection device 41 Engine control unit 42 Regeneration control unit 43 Driver detection unit 44 Driver absence time measurement unit 51 Pressure detection sensor 52 Contact switch 53 Infrared transmitter 54 Infrared receiver 55 Smart key 56 Smart key transmitter 57 Smart key receiver 100 Lower traveling body 101 Upper turning body 102 Front work machines 104a, 104b Traveling motor 105 Turning motor 106 Engine room 107 Driver's cab 108 luck Seat 111 boom 112 arm 113 bucket 114 boom cylinder 115 arm cylinder 116 bucket cylinder

Claims (6)

A filter that is disposed in the exhaust system of the engine and collects particulate matter contained in the exhaust gas, a regeneration device that regenerates the filter by burning and removing particulate matter accumulated on the filter, and operation of the regeneration device In an exhaust emission control device for a construction machine having a regeneration control device for controlling start / stop,
Driver detection means for detecting the presence or absence of a driver in the cab of the construction machine,
The exhaust control device for a construction machine, wherein the regeneration control device has a function of stopping the operation of the regeneration device when the driver detecting means detects the absence of a driver during regeneration. The exhaust purification device for a construction machine according to claim 1,
A driver absent time measuring means for measuring a driver absent time detected by the driver detecting means;
The exhaust control device for a construction machine, wherein the regeneration control device has a function of stopping the operation of the regeneration device when a driver absent time measured by the driver absent time measuring means elapses for a predetermined time. The exhaust purification device for a construction machine according to claim 1 or 2,
The exhaust gas purifying apparatus for a construction machine according to claim 1, wherein the driver detecting means includes a pressure detecting means provided in a driver seat in the driver's cab and detecting pressure by a driver seated in the driver seat. The exhaust purification device for a construction machine according to claim 1 or 2,
The exhaust gas purifying apparatus for a construction machine, wherein the driver detecting means is provided in a driver seat in the driver's cab and has a contact switch for a safety belt worn by a driver seated in the driver seat. The exhaust purification device for a construction machine according to claim 1 or 2,
The exhaust gas purifying apparatus for a construction machine, wherein the driver detecting means includes an infrared device having an infrared transmitter and an infrared receiver provided corresponding to the driver seat. The exhaust purification device for a construction machine according to claim 1 or 2,
The exhaust detection device for a construction machine, wherein the driver detection means includes a transmitter provided on a key for starting the construction machine and a receiver for receiving a signal of the transmitter.

Images