JP4392282B2 - Filter clogging detection method, filter clogging elimination method, and filter clogging detection device - Google Patents

Description

  The present invention relates to a filter clogging detection method, a filter clogging elimination method, and a filter clogging detection device that detect clogging of a black smoke removal filter that can be regenerated by the temperature of exhaust gas discharged from an engine.

  As shown in FIG. 5, a black smoke purification device 3 for removing black smoke in exhaust gas discharged from an engine 2 that drives a hydraulic pump 1 of a hydraulic circuit is mounted on a hydraulic excavator for a tunnel or the like. .

This black smoke purification device 3 is provided with a black smoke removal filter 5 in which an oxidation catalyst is supported on a porous ceramic honeycomb structure in a filter casing 4, and when the engine 2 is operated at a high load, The oxidation catalyst is activated by the temperature of the exhaust gas that has become, and the soot collected in the black smoke removal filter 5 burns to regenerate (see, for example, Patent Document 1).
JP 2002-309923 A (page 3, FIG. 3)

  The black smoke purification device 3 does not burn soot trapped by the black smoke removal filter 5 because the exhaust gas temperature does not rise sufficiently when there are many light work or idling loads.

  Therefore, there is a problem that the black smoke removal filter 5 is clogged and the output of the engine 2 is reduced or, in a remarkable case, the engine exhaust pressure is increased and the engine 2 is stopped.

  The present invention has been made in view of the above points, and is a filter that can grasp the clogging state of a black smoke removal filter that can be regenerated by the exhaust gas temperature discharged from the engine without using a pressure sensor or a temperature sensor. It is an object of the present invention to provide a clogging detection method, a filter clogging elimination method obtained by developing this filter clogging detection method, and a filter clogging detection device that implements this filter clogging detection method.

According to the first aspect of the present invention, the black that can be regenerated by the exhaust gas temperature discharged from the engine controlled to a constant engine speed / engine output torque characteristic by instructing a constant engine speed set value by the engine speed setter. A filter clogging detection method that detects clogging of a smoke removal filter, and obtains an engine speed actual measurement value for the filter regeneration limit temperature for each engine speed setting value, and an engine speed actual measurement value for the filter regeneration limit temperature. The function table that determines whether the exhaust gas temperature of the black smoke removal filter is in the regeneration range or the non-regeneration range is created, and the engine speed setting value and the engine speed measurement value are read, and the engine speed measurement value is First-order lag filter processing is performed to determine the exhaust gas temperature, and the engine speed setting value And whether the exhaust gas temperature of the black smoke removal filter is in the regeneration area or non-regeneration area from the function table based on the measured engine speed and the non-regeneration area time by counting the time in the non-regeneration area. This is a filter clogging detection method that outputs a filter clogging signal when a predetermined time is reached. The engine speed measurement value is subjected to first-order lag filtering to obtain the exhaust gas temperature, and the engine speed set value and engine speed measurement value are obtained. Based on the function table, it is determined whether the exhaust gas temperature of the black smoke removal filter is in the regeneration area or non-regeneration area, and if the non-regeneration area has reached the specified time, a filter clogging signal is output. Therefore, it is possible to grasp the clogging status of the black smoke removal filter that can be regenerated by the exhaust gas temperature discharged from the engine without using a pressure sensor or temperature sensor. It is possible.

  The invention according to claim 2 is a filter clogging elimination method for operating the engine at a high load when a filter clogging warning signal is output by the filter clogging detection method according to claim 1, and is discharged from the engine. By grasping the clogging status of the black smoke removal filter that can be regenerated by the exhaust gas temperature without using a pressure sensor or temperature sensor, the clogging of the black smoke removal filter is eliminated by operating the engine at a high load. It becomes possible to do.

According to a third aspect of the present invention, a black which can be regenerated by exhaust gas temperature discharged from an engine controlled to a constant engine speed / engine output torque characteristic by instructing a constant engine speed set value by an engine speed setter. A filter clogging detection device for detecting clogging of a smoke removal filter, which is an engine speed setting device for instructing an engine speed setting value, an engine speed sensor for detecting an engine speed actual value, and an engine speed actual value as a primary The relationship between the primary delay circuit that calculates exhaust gas temperature by delay filter processing, and the actual engine speed value of the filter regeneration limit temperature for each engine speed setting value, and the engine speed setting value and the actual engine speed value of the filter regeneration limit temperature The exhaust gas temperature of the black smoke removal filter is in the regeneration range A function table that determines whether or not it is in the non-reproduction area, a non-reproduction area timer that counts the non-reproduction area time and outputs a filter clogging signal when the non-reproduction area time reaches a predetermined time, A filter clogging detection device comprising a warning means for receiving a filter clogging signal from a regeneration zone timer and outputting a warning signal, wherein the exhaust gas temperature is obtained by subjecting an actual engine speed to a first-order lag filter process by a first-order lag circuit And determine whether the exhaust gas temperature of the black smoke removal filter is in the regeneration region or the non-regeneration region based on the engine speed setting value and the engine speed actual measurement value using the function table. When the time is reached, a filter clogging signal is output from the non-regeneration area timer to the warning means, so that the black smoke removal filter that can be regenerated by the exhaust gas temperature discharged from the engine is output. Other clogging conditions, it is possible to grasp without using a pressure sensor or a temperature sensor.

  According to a fourth aspect of the present invention, in the filter clogging detection device according to the third aspect, a reproduction area timer that counts the time in the reproduction area determined by the function table, and a reproduction state that is counted by the reproduction area timer is constant. When the number of times that the time has continued is further counted and reaches a predetermined value, it is considered that the black smoke removal filter has been regenerated, and a regeneration rate counter that resets the non-reproduction area timer is provided. The number of times that the playback state has continued for a certain period of time is further counted by the playback rate counter, and when it reaches the predetermined value, the black smoke removal filter is considered to have been played back and the non-playback zone timer is reset. Can be accurately counted.

  According to the first aspect of the present invention, the exhaust gas temperature is obtained by first-order lag filter processing of the engine speed actual measurement value, and the exhaust gas temperature of the black smoke removal filter is obtained from the function table based on the engine speed set value and the engine speed actual measurement value. Is in the regeneration zone or in the non-regeneration zone, and when the time in the non-regeneration zone reaches a predetermined time, a filter clogging signal is output, so it can be regenerated by the exhaust gas temperature exhausted from the engine. The clogging status of the black smoke removal filter can be grasped without using a pressure sensor or a temperature sensor.

  According to the invention described in claim 2, the clogging state of the black smoke removal filter that can be regenerated by the exhaust gas temperature discharged from the engine is grasped without using a pressure sensor or a temperature sensor, and the engine is operated at a high load. By doing so, clogging of the black smoke removal filter can be eliminated.

  According to the third aspect of the invention, the exhaust gas temperature is obtained by first-order lag filter processing of the engine speed actual measurement value by the first-order lag circuit, and black smoke based on the engine speed setting value and the engine speed actual measurement value by the function table. Determine whether the exhaust gas temperature of the removal filter is in the regeneration area or non-regeneration area, and output a filter clogging signal from the non-regeneration area timer to the warning means when the non-regeneration area time reaches a predetermined time Therefore, the clogging state of the black smoke removal filter that can be regenerated by the exhaust gas temperature discharged from the engine can be grasped without using a pressure sensor or a temperature sensor.

  According to the fourth aspect of the present invention, the black smoke removal filter is reproduced when the reproduction rate counter further counts the number of times that the reproduction state continues for a certain period of time counted by the reproduction area timer and reaches a predetermined value. Since the non-reproduction area timer is reset, the time of the non-reproduction area can be accurately counted.

  Hereinafter, the present invention will be described in detail with reference to an embodiment shown in FIGS.

  As shown in FIG. 1, a working machine such as a hydraulic excavator for work in a tunnel includes an engine 12 that drives a hydraulic pump 11 that supplies hydraulic oil to a hydraulic circuit, and black in exhaust gas discharged from the engine 12. A black smoke purification device 13 for removing smoke is mounted.

  This black smoke purification device 13 is provided with a black smoke removal filter 15 in which an oxidation catalyst is supported on a porous ceramic honeycomb structure in a filter casing 14. When the engine 12 is operated at a high load, the engine 12 The oxidation catalyst is activated by the high temperature exhaust gas discharged from the combustion chamber, and the soot collected by the black smoke removal filter 15 is burned, so that the clogging caused by this soot is eliminated and the black smoke removal filter 15 is regenerated. Has function.

  The control system of the engine 12 includes an accelerator dial 21 as an engine speed setting device that instructs an accelerator dial setting value as an engine speed setting value, and an engine speed sensor 22 that detects an actual engine speed as an engine speed actual value. However, it is equipped as standard.

  In addition, a controller 23 is provided for inputting the accelerator dial set value and the actual engine speed and performing arithmetic processing. The controller 23 includes a central processing unit (CPU) having an arithmetic function and a memory (ROM, RAM, etc.) for storing programs, data, and the like.

  Further, the controller 23 includes a primary delay circuit 24 that obtains the exhaust gas temperature by performing a primary delay filter process on the actual engine speed, and the black smoke removal filter 15 based on the accelerator dial set value and the actual engine speed. And a function table 25 for determining whether the exhaust gas temperature is in the regeneration region or the non-regeneration region.

  This function table 25 obtains the actual engine speed of the filter regeneration limit temperature for each accelerator dial set value, and determines the exhaust gas temperature of the black smoke removal filter from the relationship between the accelerator dial set value and the engine actual speed of the filter regeneration limit temperature. Is a memory in which data is mapped in advance.

  Further, the controller 23 counts the time of the non-reproduction area, and when the time of the non-reproduction area reaches a predetermined time, the control table 23 outputs a filter clogging signal, and the function table 25 determines The playback area timer 27 for counting the time in the playback area, and when the playback area timer 27 counts the number of times the playback state has continued for a certain period of time and reaches a predetermined value, the black smoke removal filter 15 A reproduction rate counter 28 that resets the non-reproduction area timer 26 on the assumption that it has been reproduced is provided.

  The non-regeneration area timer 26 of the controller 23 is connected to an alarm device 29 as warning means for receiving a filter clogging signal from the non-regeneration area timer 26 and outputting a warning signal.

  Next, the creation of the function table 25 will be described. As shown in FIG. 3, when the load torque is applied to the engine 12, the engine speed decreases along each governor characteristic line from each accelerator dial set value. However, the exhaust gas temperature rises as shown in FIG.

  Therefore, the actual engine speed of the filter regeneration limit temperature is obtained for each accelerator dial set value based on the bench test result of the engine 12, and the relationship between the accelerator dial set value and the engine actual speed of the filter regeneration limit temperature is calculated. As shown in FIG. 3, the filter regeneration limit line in the engine speed / engine output torque characteristic is determined, and the upper region of the filter regeneration limit line is set as the regeneration region and the lower region is set as the non-regeneration region. Even if the exhaust gas temperature of the smoke removal filter 15 is not measured, the function table 25 for determining whether the exhaust gas temperature of the black smoke removal filter 15 is in the regeneration region or the non-regeneration region can be created.

  Further, the accelerator dial set value and the value obtained by subjecting the actual engine speed to the first-order lag filter processing by the first-order lag circuit 24, that is, the exhaust gas temperature, are input to the function table 25, so that the black smoke removal filter 15 Or in the non-reproduction area.

  As shown in FIG. 4 (c), even if the exhaust gas temperature reaches the soot combustion temperature, the black smoke removal filter 15 must be maintained if the state of the regeneration region above the filter regeneration limit temperature (about 400 ° C.) does not continue for a certain period of time. Since the soot trapped in is not burned, the number of times that the state of the regeneration zone continues for a certain time is counted, and when the predetermined number of times is reached, it can be estimated that the black smoke removal filter 15 has been regenerated.

  Based on such an idea, a clog of the black smoke removal filter 15 can be predicted in advance by a calculation shown in the flowchart of FIG.

  A filter clogging detection method for detecting clogging of the black smoke removal filter 15 that can be regenerated by the exhaust gas temperature discharged from the engine 12 will be described below based on the flowchart shown in FIG.

(Step 1)
The values counted by the playback area timer 27 and the non-reproduction area timer 26 are read from the external memory.

(Step 2)
The accelerator dial set value is read from the accelerator dial 21, and the actual engine speed is read from the engine speed sensor 22.

(Step 3)
Since the exhaust gas temperature can be approximated with a first order lag with respect to the actual engine speed, the exhaust gas temperature is obtained by performing a first order lag filtering process on the actual engine speed.

(Step 4)
It is determined whether the engine 12 has stopped.

(Step 5)
When the engine 12 is stopped, the values counted by the regeneration zone timer 27 and the non-reproduction zone timer 26 are stored in the external memory, and this value is used in step 1.

(Step 6)
From the function table 25, the exhaust gas temperature of the black smoke removal filter 15 is in the regeneration region or in the non-regeneration region based on the accelerator dial set value and the actual engine speed that has been subjected to the first-order lag filter processing, that is, the exhaust gas temperature. Determine whether.

(Step 7)
If it is in the playback area, the playback area timer 27 is counted up and the time in the playback area is counted up.

(Step 8)
It is determined whether or not the playback area timer 27 has reached a predetermined time, and the process returns to step 2 until the playback area timer 27 reaches a predetermined time.

(Step 9)
When the playback area timer 27 reaches a predetermined time, the playback area counter 27 that counts the number of times the playback state has continued for a certain period of time is counted up and the playback area timer 27 is reset.

(Step 10)
It is determined whether or not the reproduction rate counter 28 has reached the predetermined number of times, and the process returns to step 2 until the reproduction rate counter 28 reaches the predetermined number of times.

(Step 11)
When the regeneration rate counter 28 reaches a predetermined value in step 10, the non-reproduction area timer 26 that counts the non-reproduction area time is reset, assuming that the black smoke removal filter 15 has been regenerated.

(Step 12)
If the function table 25 determines in step 6 that the black smoke removal filter 15 is in the non-reproduction area, the non-reproduction area timer 26 is counted up and the time in the non-reproduction area is counted.

(Step 13)
The playback area timer 27 is reset.

(Step 14)
It is determined whether or not the non-reproduction area timer 26 has reached a predetermined time, and the process returns to step 2 until the non-reproduction area timer 26 reaches a predetermined time.

(Step 15)
When the non-reproduction area time counted by the non-reproduction area timer 26 reaches a predetermined time, a filter clogging signal is output to the alarm device 29, from which a visual or audible warning signal is output. Is output to prompt the operator to perform a regeneration operation.

  When a warning signal for filter clogging is output, the operator activates the relief valve so that the operating state continues even after operating the hydraulic actuator used in a hydraulic excavator to the dead point. The exhaust gas temperature exhausted from the engine 12 is raised to 400 ° C. or higher by operating the engine 12 at a high load, such as a relief operation that continues to be operated, and the black smoke is burned and removed by this exhaust gas temperature. Then, the black smoke removal filter 15 is regenerated.

  Thus, the exhaust gas temperature is obtained by subjecting the actual engine speed to the first-order lag filter processing by the first-order lag circuit 24, and the black smoke removal filter 15 of the function table 25 based on the engine speed set value and the actual engine speed. It is determined whether the exhaust gas temperature is in the regeneration zone or non-regeneration zone, and if the non-regeneration zone time reaches a predetermined time, a filter clogging signal is output from the non-regeneration zone timer 26 to the alarm 29. The clogging state of the black smoke removal filter 15 that can be regenerated by the exhaust gas temperature discharged from the engine 12 can be grasped without using a pressure sensor or a temperature sensor.

  That is, without adding a device such as a differential pressure detector to the black smoke purification device 13, the clogging situation of the black smoke removal filter 15 is estimated using the accelerator dial setting value of the conventional hydraulic excavator and the actual engine speed. Therefore, a clogging alarm can be output easily by incorporating an arithmetic processing function into the controller 23 of the hydraulic excavator.

  When the clogging state of the black smoke removal filter 15 can be grasped, the clogging of the black smoke removal filter 15 can be eliminated by operating the engine 12 at a high load.

  Further, the number of times that the reproduction state has been counted for a certain period of time counted by the reproduction area timer 27 is further counted by the reproduction rate counter 28, and when the predetermined value is reached, it is considered that the black smoke removal filter 15 has been reproduced and the non-reproduction area Since the timer 26 is reset, the time in the non-reproduction area can be accurately counted.

  The present invention is not limited to the engine 12 of a hydraulic excavator, but can be applied to other work machines or engines of vehicles.

It is a block diagram which shows one Embodiment of the filter clogging detection method and its apparatus based on this invention. It is a flowchart which shows the detection method same as the above and the control procedure of the apparatus. It is an engine speed-engine output torque characteristic view for determining the regeneration region and the non-reproduction region used in the detection method and the apparatus thereof. (A) is a graph showing the change over time of the load torque, (b) is a graph showing the change over time of the load torque of (a) and the change over time of the engine speed, and (c) is a graph of the load torque of (a). It is a graph which shows a time-dependent change of exhaust gas temperature corresponding to a time-dependent change, and shows the regeneration temperature range which the soot trapped by the black smoke removal filter burns, and the non-regeneration temperature range which does not burn. It is explanatory drawing of the prior art example which attached the black smoke purification apparatus to the engine.

Explanation of symbols

12 engine
13 Black smoke removal filter
21 Accelerator dial as engine speed setting device
22 Engine speed sensor
24 1st delay circuit
25 Function table
26 Non-reproduction area timer
27 Playback area timer
28 Playback rate counter
29 Alarm as a warning means

Claims (4)

Detects clogging of the black smoke removal filter that can be regenerated by the exhaust gas temperature discharged from the engine, which is controlled to a constant engine speed and engine output torque characteristics by instructing a constant engine speed setting value with the engine speed setting device A filter clogging detection method for
Determine the actual engine speed value of the filter regeneration limit temperature for each engine speed setting value, and check whether the exhaust gas temperature of the black smoke removal filter is in the regeneration range based on the relationship between the engine speed setting value and the actual engine speed value of the filter regeneration limit temperature. Create a function table that determines whether it is in the playback area,
Read the engine speed setting value and the actual engine speed value,
Obtain the exhaust gas temperature by performing first-order lag filtering on the measured engine speed,
Determine whether the exhaust gas temperature of the black smoke removal filter is in the regeneration area or non-regeneration area from the function table based on the engine speed setting value and the engine speed actual measurement value,
A filter clogging detection method, comprising: counting a non-reproduction area time and outputting a filter clogging signal when the non-reproduction area time reaches a predetermined time. A filter clogging elimination method, comprising: operating an engine at a high load when a filter clogging warning signal is output by the filter clogging detection method according to claim 1. Detects clogging of the black smoke removal filter that can be regenerated by the exhaust gas temperature discharged from the engine, which is controlled to a constant engine speed and engine output torque characteristics by instructing a constant engine speed setting value with the engine speed setting device A filter clogging detection device,
An engine speed setting device for indicating the engine speed setting value;
An engine speed sensor that detects the actual measured engine speed;
A first-order lag circuit that obtains the exhaust gas temperature by first-order lag filtering the measured engine speed;
Determine the actual engine speed value of the filter regeneration limit temperature for each engine speed setting value, and check whether the exhaust gas temperature of the black smoke removal filter is in the regeneration range based on the relationship between the engine speed setting value and the actual engine speed value of the filter regeneration limit temperature. A function table that determines whether it is in the playback area;
A non-reproduction area timer that counts the non-reproduction area time and outputs a filter clogging signal when the non-reproduction area time reaches a predetermined time;
A filter clogging detection device comprising: warning means for receiving a filter clogging signal from a non-regeneration area timer and outputting a warning signal. A playback area timer that counts the time in the playback area determined by the function table;
A regeneration rate counter that counts the number of times the regeneration state has continued for a certain period of time counted by the regeneration area timer and resets the non-reproduction area timer by assuming that the black smoke removal filter has been regenerated when the predetermined value is reached. The filter clogging detection device according to claim 3, wherein the filter is clogged.

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