KR20140093322A - Exhaust purification system for construction machine - Google Patents

Exhaust purification system for construction machine Download PDF

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Publication number
KR20140093322A
KR20140093322A KR1020130004050A KR20130004050A KR20140093322A KR 20140093322 A KR20140093322 A KR 20140093322A KR 1020130004050 A KR1020130004050 A KR 1020130004050A KR 20130004050 A KR20130004050 A KR 20130004050A KR 20140093322 A KR20140093322 A KR 20140093322A
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KR
South Korea
Prior art keywords
regeneration
filter
pressure
engine
exhaust gas
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Application number
KR1020130004050A
Other languages
Korean (ko)
Inventor
김성수
Original Assignee
현대중공업 주식회사
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Priority to KR1020130004050A priority Critical patent/KR20140093322A/en
Publication of KR20140093322A publication Critical patent/KR20140093322A/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2250/00—Combinations of different methods of purification
    • F01N2250/02—Combinations of different methods of purification filtering and catalytic conversion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2590/00—Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines
    • F01N2590/08—Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines for heavy duty applications, e.g. trucks, buses, tractors, locomotives
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/08—Parameters used for exhaust control or diagnosing said parameters being related to the engine

Abstract

The present invention relates to an exhaust gas purification system for a construction machine, which can avoid the reduction in output due to an increase in the pressure of exhaust gas immediately before regeneration by performing regeneration of a filter prior to the deposition of a large quantity of PM in the filter, and can reduce the possibility of an abnormal increase in a temperature inside the filter caused by the combustion of the PM during regeneration or of the combustion of the filter caused thereby. An operator may place the entire manipulation tools in a not-manipulated state for a fixed period of time with an engine (1) started inside an operation room between work with a hydraulic excavator, such as during a rest inside the operation room. At this time, a controller (4) for monitoring the state controls the revolutions per minute (RPM) of the engine (1) at a pressure detection value of a differential pressure detecting device (36) higher than a second fixed pressure (P2), and then initiates forcible regeneration in order to combust and remove the deposited PM in the filter, when the not-manipulated state continues for a fixed time (Ta). In addition, the controller terminate the automatic regeneration and restores to a general engine control state when the pressure detection value of the differential pressure detecting device (36) becomes lower than a first fixed pressure (P1).

Description

[0001] EXHAUST PURIFICATION SYSTEM FOR CONSTRUCTION MACHINE [0002]

The present invention relates to an exhaust gas purifying system for a construction machine. More particularly, the present invention relates to an exhaust gas purifying system for a construction machine. More particularly, the present invention relates to a system for purifying exhaust gas, And to an exhaust gas purification system of a construction machine for regenerating a filter.

A construction machine such as a hydraulic excavator is equipped with a diesel engine as its driving source. However, the emission amount of particulate matter (hereinafter referred to as "PM") discharged from the diesel engine together with NOx, CO, Regulation is being strengthened.

Regarding such regulations, there is known an exhaust gas purifying system that collects PM by a filter called a diesel particulate filter (DPF) to reduce the amount of PM discharged to the outside.

In this exhaust gas purifying system, when the PM replenishment amount of the filter is increased, the filter is clogged and the back pressure of the engine is thereby increased, thereby causing deterioration of the fuel efficiency. Therefore, PM captured in the filter is appropriately combusted to remove clogging The filter is playing.

Regeneration of the filter is usually performed by using an oxidation catalyst.

In some cases, in order to activate the oxidation catalyst, the temperature of the exhaust gas must be higher than the activation temperature of the oxidation catalyst. For this purpose, forced regeneration is performed by forcibly raising the exhaust gas temperature to a temperature higher than the activation temperature of the oxidation catalyst.

This forced regeneration includes a method of raising the temperature of the exhaust gas by performing sub injection (post injection) of injecting fuel in the expansion stroke after the main injection of the engine and a method of regenerating the exhaust gas by the regenerative fuel injection device provided in the exhaust pipe And a method of raising the temperature of the exhaust gas by injecting fuel into the flowing exhaust gas.

Further, forcibly regeneration of the filter includes manual regeneration to start regeneration by an operation input of the operator and regeneration to automatically start regeneration.

Conventionally, the PM accumulation amount (accumulation amount) of the filter is estimated as a condition for starting these forced regeneration, and the regeneration is performed when the PM accumulation amount reaches the PM accumulation limit value.

In this case, the PM accumulation amount is generally determined by detecting the differential pressure across the filter and calculating the PM accumulation amount based on the detected differential pressure value.

As described above, in the conventional exhaust gas purifying system, the PM accumulation amount of the filter is estimated, and forced regeneration is started when the PM accumulation amount reaches a predetermined value.

However, since this regeneration is carried out after a large amount of PM is collected in the filter, there is a problem that the output is lowered due to the rise of the exhaust gas pressure just before regeneration.

Further, when the PM accumulation amount can not be accurately grasped, there is a problem that the internal temperature of the filter rises abnormally due to burning of a large amount of collected PM and the problem of melting of the filter derived therefrom.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide an exhaust gas purifying apparatus for regenerating a filter before a large amount of PM is deposited on the filter, So as to avoid deterioration.

It is another object of the present invention to provide an exhaust gas purifying system for a construction machine that reduces the possibility of abnormal increase in the internal temperature of the filter due to combustion of PM when regenerated, and the possibility of causing the filter to lose its melting point.

According to the present invention,

The present invention relates to an exhaust gas purifying system for a construction machine having a diesel engine, a plurality of driven members driven by the power of the engine, and an operating means for instructing the operation of the plurality of driven members,

A filter disposed in an exhaust system of the engine for trapping particulate matter contained in the exhaust gas;

A regeneration device for burning particulate matter deposited on the filter to burn off the particulate matter to regenerate the filter,

Operation detecting means for detecting presence / absence of operation of the operating means,

And a reproduction control device for operating the reproduction apparatus when the operation detection means detects the operation state of the operation means and the operation state of the operation means continues for a predetermined time.

In addition,

And stops the operation of the reproducing apparatus when the operation detecting means detects the presence of the operation of the operating means during the operation of the reproducing apparatus.

Further,

And a target rotational speed command means for commanding a target rotational speed,

The playback control device includes:

And stops the operation of the playback apparatus when the target rotation speed instructed by the target rotation speed command means changes during operation of the playback apparatus.

Further,

Further comprising a pressure detecting device for detecting a pressure loss,

The playback control device includes:

And stops the operation of the reproducing apparatus when the pressure loss detected by the pressure detecting device becomes lower than the first predetermined pressure value.

Further,

Further comprising a pressure detecting device for detecting a pressure loss,

The playback control device includes:

When the operating state of the operating means is detected by the operation detecting means and the sub operating state continues for a predetermined time and the pressure loss detected by the pressure detecting device is higher than the second predetermined pressure, .

In addition,

The control means controls the rotation speed of the engine to a predetermined rotation speed when the sub operation state of the operation means is detected by the operation detection means and the sub operation state continues for a predetermined time to operate the reproduction apparatus.

Further,

And a target rotational speed command means for commanding a target rotational speed,

The playback control device includes:

When the operating state of the operating means is detected by the operation detecting means and the sub operating state continues for a predetermined time and the target rotational speed commanded by the target rotational speed command means is higher than the predetermined rotational speed, Thereby operating the apparatus.

In addition,

And an oxidizing catalyst disposed on an upstream side of the filter and a fuel supply means for supplying fuel to the oxidizing catalyst, wherein the exhaust gas of the engine is forcibly heated to a temperature higher than an activation temperature of the oxidation catalyst, After activation, the fuel is supplied to the oxidation catalyst from the fuel supply means, the temperature of the exhaust gas is raised by the heat of reaction between the fuel and the oxidation catalyst, and the particulate matter deposited on the filter is burned and removed.

As described above, according to the present invention, since the filter can be regenerated before a large amount of PM is deposited on the filter, there is an effect of preventing the output from decreasing due to the rise in the pressure of the exhaust gas immediately before the regeneration.

There is an effect of reducing the possibility of causing abnormal rise in the internal temperature of the filter due to burning of PM when regeneration of the filter is carried out and loss of the filter resulting therefrom.

In addition, when the operator intends to resume the operation during the forced regeneration, the operator can immediately resume the operation because the forced regeneration is immediately terminated when the operating means is operated.

In addition, when the operator intends to resume the operation during the forced regeneration of the filter to operate the target revolving speed command means, the forced regeneration is immediately terminated, so that the operation can be restarted quickly.

In addition, since the reproduction is automatically terminated when the differential pressure between the before and after the filter is lower than the first predetermined pressure, the operator can rest without worrying about the fact that the filter is being regenerated.

In addition, there is a tendency to prevent the deterioration of the service life due to the excessive combustion of the filter.

Further, even when the sub-operating state of the operating means is detected by the operation detecting means and the sub operating state continues for the predetermined time, the forced regeneration is not started when the differential pressure across the filter is not higher than the second predetermined pressure, Unnecessary regeneration is avoided, and the life of the filter can be prevented.

1 is a diagram showing an overall configuration of an exhaust gas purifying system of a construction machine according to an embodiment of the present invention,
2 is a view showing a hydraulic drive apparatus mounted on a construction machine (hydraulic excavator), and Fig.
FIG. 3 is a view showing an outer appearance of a hydraulic excavator, which is an example of a construction machine having the hydraulic drive apparatus shown in FIG. 2,
Fig. 4 is a flowchart showing the calculation contents of the filter regeneration calculation process of the controller shown in Fig. 1,
5 is a diagram showing the relationship between the PM accumulation amount of the filter and the differential pressure across the filter,
6 is a flowchart showing the calculation contents of the filter regeneration calculation process of the controller in the exhaust gas purifying system of the construction machine according to another embodiment of the present invention.

1, a diesel engine 1 (hereinafter referred to as "engine") mounted on a construction machine (for example, a hydraulic excavator) provided with an exhaust gas purifying system according to the present invention includes an electronic fuel injection control device And an electronic governor 1a as an electronic governor.

The target rotational speed of the engine 1 is instructed by the engine control dial 2 and the actual rotational speed of the engine 1 is detected by the rotational speed detecting device 3. [

The command signal of the engine control dial 2 and the detection signal of the rotational speed detecting device 3 are input to the controller 4. The controller 4 outputs the command signal (target rotational speed) and the detected signal (actual rotational speed) Controls the electronic governor 1a, and controls the revolution speed and torque of the engine 1. [

A key switch 5 is provided as a start and stop command device of the engine 1. A command signal of the key switch 5 is also inputted to the controller 4 and the controller 4 controls the engine 1).

2 is a diagram showing a hydraulic drive apparatus mounted on a construction machine (for example, a hydraulic excavator). The hydraulic drive apparatus includes a main hydraulic pump 11 of a variable capacity type driven by an engine 1, A plurality of hydraulic actuators including a hydraulic motor 13 and hydraulic cylinders 14 and 15 driven by pressure oil discharged from a hydraulic pump 11 and a plurality of hydraulic motors A plurality of flow control valves including pilot operated flow control valves 17 to 19 for controlling the flow (flow amount and direction) of the hydraulic oil supplied to the hydraulic motor 13 and the hydraulic cylinders 14 and 15, A pilot relief valve 21 for maintaining the pressure of the hydraulic oil discharged from the pump 3 constant and forming a pilot hydraulic pressure source 20; a pilot relief valve 21 connected to the downstream side of the pilot hydraulic pressure source 20, The gate lock lever And an electromagnetic switching valve 23 connected to the pilot flow path 24 on the downstream side of the electromagnetic switching valve 23 and configured to apply the hydraulic pressure of the pilot hydraulic pressure source 20 to the pressure- And remote control valves 25, 26 and 27 for generating control pilot pressures a to f for operating the flow control valves 17 to 19, respectively.

The remote controller valves 25, 26 and 27 are operated by left and right operating levers 28 and 29 provided on the left and right sides of the driver's seat. The operating levers 28 and 29 can be operated in the cross direction, The remote controller valve 25 is operated and the remote controller valve 27 is operated when the operation lever 28 is operated in the other direction of the cross and the operation lever 29 is operated The remote controller valve 26 is operated and the remote controller valve (not shown) is operated when the operation lever 29 is operated in the other direction of the cross.

When the operation lever 28 is operated in one direction from the neutral position, when the operation lever 28 is operated in one direction from the neutral position, the remote controller valve 25 generates the control pilot pressure (a) The remote controller valve 25 generates the control pilot pressure b.

The control pilot pressures a and b are guided to the corresponding pressure receiving portions of the flow control valve 17 through the respective pilot lines 25a and 25b so that the flow control valve 17 is switched from the neutral position.

Likewise, when the operation lever 28 is operated in the other direction of the crucible, when the remote controller valve 27 is operated in one direction from the neutral position, the remote control valve 27 generates the control pilot pressure e and operates in the opposite direction from the neutral position The remote controller valve 27 generates the control pilot pressure f and the control pilot pressures e and f are led to the corresponding hydraulic pressure portions of the flow control valve 19 through the respective pilot lines 27a and 27b , Whereby the flow control valve 19 is switched from the neutral position.

When the operation lever 29 is operated in one direction of the crucible, the control pilot pressure c is generated by operating in one direction from the neutral position, and when the operation lever 29 is operated in the opposite direction from the neutral position, the control pilot pressure d is generated , The control pilot pressures c and d are guided to the corresponding pressure receiving portions of the flow control valve 18 through the respective pilot lines 26a and 26b so that the flow control valve 18 is switched from the neutral position.

3 is a diagram showing an outer appearance of a hydraulic excavator (hereinafter referred to as an "excavator"), which includes a lower traveling body 100, an upper revolving body 101, and a front working machine 102.

The lower traveling body 100 has left and right crawler traveling devices 103a and 103b and is driven by the left and right traveling motors 104a and 104b.

The upper swing body 101 is swingably mounted on the lower traveling body 100 by a swing motor 105 and the front swinging machine 102 is swingably mounted on the front portion of the upper swing body 101.

An engine 1 is disposed in an engine room 106 and a gate lock lever (not shown) is provided at an entrance of a driver's seat in a cab 107 And the operation levers 28 and 29 of the remote controller valves 25, 26, and 27 are disposed on the left and right of the driver's seat.

The front working machine 102 is a multi-joint structure having a boom 111, an arm 112 and a bucket 113. The boom 111 rotates up and down by expansion and contraction of the boom cylinder 114, And the bucket 113 rotates up and down and back and forth by the expansion and contraction of the bucket cylinder 116. The bucket cylinder 116 is rotated in the vertical direction by the expansion and contraction of the arm cylinder 115,

2, the hydraulic motor 13 corresponds to the swing motor 105, the hydraulic cylinder 14 corresponds to the arm cylinder 115, and the hydraulic cylinder 15 corresponds to the boom cylinder 114 .

Although the illustrated hydraulic drive apparatus is provided with other hydraulic actuators and control valves corresponding to the traveling motors 104a and 104b, the bucket cylinder 116, and their operating means, they are not shown in Fig.

The exhaust gas purifying system of the present embodiment is provided in the construction machine (hydraulic excavator) as described above.

1, the exhaust gas purifying system is disposed in an exhaust pipe 31 constituting an exhaust system of the engine 1 and includes a filter 32 for collecting particulate matter contained in the exhaust gas, The DPF apparatus 34 including the oxidation catalyst 33 disposed on the upstream side and the operation of all the operation means including the operation levers 28 and 29 (Fig. 2) of the remote controller valves 25 to 27 (Pressure loss of the filter 32) on the upstream side and the downstream side of the filter 32 and a shuttle valve group 40 and a pressure detection device 35 constituting the operation detection means for detecting the pressure difference An exhaust temperature detecting device 37 provided on the upstream side of the filter for detecting the temperature of the exhaust gas, a display device (monitor) 38, an engine 1 of the exhaust pipe 31, And a regeneration fuel injection device 39 provided between the DPF device 34 and the regeneration fuel injection device 39.

The oxidation catalyst 33 and the fuel injector 39 for regeneration constitute a regenerating apparatus for burning PM (particulate matter) deposited on the filter 32 and burning it to regenerate the filter 32.

The shuttle valve group 40 includes shuttle valves 41 to 46 as shown in Figure 2 and the shuttle valve 41 is connected between the pilot lines 25a and 25b of the remote controller valve 25 The shuttle valve 42 is connected between the pilot lines 26a and 26b of the remote controller valve 26 and the shuttle valve 43 is connected between the pilot lines 27a and 27b of the remote controller valve 27 The shuttle valve 44 is connected between the output ports of the shuttle valves 41 and 42 and the shuttle valve 45 is connected between the output ports between the shuttle valves 43 and 44, And is connected between the output port of the shuttle valve 45 and the output port of the shuttle valve at the final stage related to the remote controller valve of another operating means not shown.

Thereby, the shuttle valve group including the shuttle valves 41 to 46 can control the control pilot pressure (a to f) of the remote controller valves 25 to 27 or the control pilot pressure of the remote controller valve The shuttle valve 46 at the final stage of the shuttle valve group 40 outputs the maximum pressure.

The pressure detecting device 35 is connected to the output port of the shuttle valve 46 at the final stage and detects the maximum pressure which is the output pressure of the shuttle valve 46 so that the operating levers 28, 29) of the entire operating means.

The detection signals of the pressure detecting device 35, the differential pressure detecting device 36 and the exhaust temperature detecting device 37 are inputted to the controller 4 so that the controller 4 outputs the input signals to the above- ) And the key switch 5, and controls the electronic governor 1a and the fuel injector 39 for regeneration according to the calculation result.

The controller 4 also stores information represented by various signals of the revolution number detection device 3, the key switch 5, the pressure detection device 35, the pressure difference detection device 36, and the exhaust temperature detection device 37, The result information of the filter regeneration processing of the display device 4 is sent to the display device 38 as a display signal and their information is displayed on the display screen 38a of the display device 38. [

4 is a flowchart showing the calculation contents of the filter regeneration calculation process of the controller 4. The controller 4 first determines whether or not the remote controller valves 25-27 are on the basis of the detection signal of the pressure detecting device 35 It is judged whether or not all of the entire operating means including the operating levers 28, 29 are in the non-operated operating state (step S100).

This determination is made by previously setting, as a threshold value, a pressure slightly higher than the output pressure of the remote controller valve at the time of the negative operation of the operating means (such as the operating lever), and setting the pressure detection value of the pressure detecting device 35 to the threshold value And when it is lower, it is judged as a sub-operation.

If it is determined in step S100 that the total operation means is in the minor operation state, it is determined whether the minor operation state has continued for a predetermined time Ta (for example, five minutes) (step S110).

When it is determined in step S100 that the total operation means is not in the non-operation state (that is, either one of the operation means is being operated), or if it is determined in step S110 that the sub operation state is the predetermined time Ta Minute). When it is judged that it is not continued, the procedure returns to the procedure immediately after the start, and the procedure of steps S100 and S110 is repeated.

On the other hand, when it is determined in step S110 that the sub operating state of the total operating means has continued for the predetermined time (Ta), based on the detection signal of the differential pressure detection device 36, the pressure detection value It is determined whether or not it is higher than the second predetermined pressure P2 which is the forced regeneration start pressure (step S120).

5 shows the relationship between the PM accumulation amount of the filter 32 and the differential pressure across the filter 32. As the PM accumulation amount of the filter 32 increases, the differential pressure across the filter 32 increases.

In Fig. 5, P3 is a pressure value (pressure threshold value) of the differential pressure before and after the filter corresponding to the regeneration start PM accumulation amount in the automatic regeneration technique of the conventional filter.

In the conventional automatic filter regeneration technique, the PM accumulation amount of the filter is estimated from the differential pressure between the front and back of the filter, and forced regeneration is started when the PM accumulation amount reaches a predetermined value.

The second predetermined pressure P2 (forced regeneration start pressure) used in the determination in step S140 in FIG. 4 is set to a value slightly lower than the pressure threshold value P3 corresponding to the regeneration start PM accumulation amount (P2 < P3 ).

In Fig. 5, P1 is a first predetermined pressure for ending the forced regeneration (P1 < P2).

Here, the pressure detection value of the differential pressure detection device 36 may be used as it is, but preferably the exhaust gas temperature on the upstream side of the filter 32 detected by the exhaust temperature detection device 37 is used as the differential pressure detection device 36 are temperature-corrected, and the value obtained by this temperature correction is used.

If it is determined in step S120 of FIG. 4 that the pressure detection value of the differential pressure detection device 36 (the differential pressure across the filter 32) is not higher than the second predetermined pressure P2, the PM accumulation amount of the filter 32 is small It is determined that there is no need to perform playback, and the procedure returns to the procedure immediately after the start, and the procedure of steps S100, S110, and S120 is repeated.

When it is determined that the pressure detection value of the differential pressure detection device 36 (the differential pressure across the filter 32) is higher than the second predetermined pressure P2, the rotation speed of the engine 1 is firstly set to a predetermined rotation speed (Na) (step S130). Subsequently, forced regeneration of the filter 32 is started (step S140).

Here, in the control of the engine speed in step S130, the target rotational speed of the engine 1 is switched from the target rotational speed indicated by the engine control dial 2 to a predetermined rotational speed suitable for forced regeneration higher than the low-speed idle rotational speed , The fuel injection amount of the electronic governor 1a is feedback-controlled based on the predetermined revolution number and the actual revolution number of the engine 1 detected by the revolution number detection device 3, As shown in FIG.

The predetermined number of revolutions suitable for forced regeneration is the number of revolutions at which the temperature of the exhaust gas at that time can be raised to a temperature higher than the activation temperature of the oxidation catalyst 33 and is, for example, about 1800 rpm.

In the forcible regeneration start process of the filter 32 in step S140, for example, fuel injection (preliminary injection) for the purpose of raising the exhaust gas temperature is performed by controlling the fuel injection device 39 for regeneration first, (Main injection) for the purpose of PM fuel is performed when it is confirmed that the exhaust gas temperature detected by the exhaust gas temperature sensor 37 has been raised to the predetermined temperature.

The fuel injection for the purpose of raising the exhaust gas temperature means that the fuel is injected into the exhaust pipe 31 so that the fuel is burned 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 And is a spray for performing forced regeneration.

The fuel injection for the purpose of PM fuel means that unburned fuel is supplied to the oxidation catalyst 33 in the exhaust pipe by injecting fuel into the exhaust pipe 31 and the unburned fuel is oxidized by the oxidation catalyst 33, Is sent to the filter 32, and the PM accumulated in the filter 32 is burned and removed.

After the start of the forced regeneration in step S140, based on the detection signal of the pressure detecting device 35, it is determined whether any one of all the operation means including the operation levers 28, 29 of the remote controller valves 25-27 has been operated (Step S150). If it is determined that no operating means has been operated (in the minor operating state), it is determined whether the engine control dial 2 has been operated based on the command signal of the engine control dial 2 (The differential pressure across the filter 32) based on the detection signal of the differential pressure detection device 36 when it is determined that the engine control dial 2 is not operated (step S160) (Step S170). If it is determined that the pressure detection value is not lower than the first predetermined pressure P1, the processing of steps S150, S160, and S170 is performed Repeat.

When it is determined in step S150 that any one of all the operation means including the operation levers 28 and 29 of the remote controller valves 25 to 27 has been operated or that the engine control dial 2 has been operated in step S160 If it is determined in step S170 that the pressure detection value is lower than the first predetermined pressure P1, then the driving of the regenerative fuel injection device 39 is stopped to terminate the forced regeneration (step S180) The target engine speed of the engine 1 is switched to the target engine speed indicated by the engine control dial 2, and the normal engine control is returned (step S190).

Next, the operation of the exhaust gas purifying system of the present embodiment constructed as described above will be described.

The operator can operate the operation lever (not shown) of the remote controller valves 25 to 27 for a certain period of time while the operator has started the engine 1 in the cab, such as when the operator breaks in the cab between operations by the construction machine (hydraulic excavator) 28, 29) may not be operated.

In this case, the controller 4 monitors the state (non-operating state), and when the sub-operating state continues for the predetermined time Ta (for example, five minutes), the pressure detection value of the differential pressure detecting device 36 ) Is higher than the second predetermined pressure P2, the rotational speed of the engine 1 is controlled to a predetermined rotational speed Na suitable for regeneration, and then forced regeneration is started (step S100? S110? S120? S130? S140).

As a result, the fuel injector 39 for regeneration operates, and the PM accumulated in the filter 32 is burned and removed as described above.

When the differential pressure across the filter 32 decreases due to the removal of the incineration of the PM, the controller 4 automatically restarts the regeneration when the pressure detection value of the differential pressure detection device 36 becomes lower than the first predetermined pressure Pl And switches the target revolution speed of the engine 1 to the target revolution speed indicated by the original engine control dial 2 to return to normal engine control (steps S170, S180, and S190).

The controller 4 also detects the pressure detection value of the differential pressure detection device 36 (the differential pressure across the filter 32) even when the auxiliary operation state of all the operation means continues for a predetermined time Ta (for example, five minutes) Is not higher than the second predetermined pressure P2, the forced regeneration is not started and the sub operating state of the entire operating means is again monitored (Step S100? S110? S120? S100 ...).

Thus, unnecessary reproduction is avoided.

When the operator operates any one of all the operation means including the operation levers 28 and 29 of the remote controller valves 25 to 27 in order to resume the operation during the forced regeneration, the controller 4 detects it, The reproduction is ended and the target rotation speed of the engine 1 is switched to the target rotation speed indicated by the original engine control dial 2 to return to the normal engine control (steps S150, S180, and S190).

Thus, the operator can resume work quickly.

In a case where the operation is resumed, the target rotation speed may be set again by operating the engine control dial 2 before operating the operation means.

In this case as well, the controller 4 detects that the engine control dial 2 has been operated, immediately terminates the forced regeneration, and sets the target rotation speed of the engine 1 to the target rotation speed indicated by the original engine control dial 2 And returns to normal engine control (steps S160? S180? S190).

According to the present embodiment configured as described above, when the operator returns the entire operating means to the neutral position and the state (sub operating state) continues for a predetermined time (Ta), the reproducing apparatus automatically operates to start the forced regeneration, 32 can be delicately forcibly regenerated as compared with the case where forced regeneration is started when the PM accumulation amount of the filter 32 exceeds the regeneration start accumulation amount because the PM deposited on the filter 32 It is possible to regenerate the filter 32 before depositing a large amount of PM in the exhaust gas recirculation passage 32. This prevents the output from decreasing due to the rise of the exhaust gas immediately before the regeneration, It is possible to reduce the possibility of causing an abnormal increase in the internal temperature of the filter 32 and a loss of the filter 32 resulting therefrom.

In addition, when the operator intends to resume the operation during the forced regeneration, the operator can immediately resume the operation because the forced regeneration is immediately terminated when the operation means is operated.

In addition, even when the operator intends to resume the operation during the forced regeneration and operates the engine control dial 2, the forced regeneration is immediately terminated and the operation can be resumed quickly.

When the pressure difference between the front and rear of the filter 32 becomes lower than the first predetermined pressure P1, the regeneration is automatically terminated and the engine 1 is returned to the original control state. Therefore, Can be very convenient.

In addition, it is possible to prevent the life of the filter (32) from being deteriorated due to overheating.

When the pressure difference between the front and the rear of the filter 32 is not higher than the second predetermined pressure P2, the forced regeneration is not started. Therefore, unnecessary regeneration is avoided and the life of the filter can be prevented.

Another embodiment of the present invention will be described with reference to Fig.

6 is a flowchart showing the calculation contents of the filter regeneration calculation process of the controller in the exhaust gas purifying system of the present embodiment.

6, the same steps as those shown in Fig. 4 are denoted by the same reference numerals.

In this embodiment, whether or not the target rotational speed indicated by the engine control dial 2 is higher than a predetermined rotational speed Na for reproduction is added to the condition under which the forced regeneration is started in the arithmetic processing of the controller.

6), the controller 4 (see Fig. 1) first determines whether or not the operation lever 28, 29 of the remote controller valves 25 to 27 (Step S100). If the entire operation means is in the sub-operation state, it is determined whether or not the sub-operation state is the predetermined time Ta (for example, 5 minutes) (step S110).

 The above is the same as the above-described embodiment.

Next, in the present embodiment, it is determined whether or not the target rotation speed indicated by the engine control dial 2 is higher than a predetermined rotation speed Na which is the engine rotation speed for reproduction (step S115) The flow proceeds to step S120 where the pressure detection value (front-back differential pressure of the filter 32) is determined based on the detection signal of the differential pressure detection device 36 as in the above-described embodiment, When the target revolving speed is not higher than the predetermined revolving speed Na for reproduction, the process returns to the procedure immediately after the start, and the process returns to steps S100, S110, S115 Is repeated.

The other processes are the same as those in the above-described embodiment shown in Fig.

Whether or not the target rotational speed indicated by the engine control dial 2 is higher than the predetermined rotational speed Na for regeneration is determined based on the pressure detection value of the differential pressure detection device 36 ] Is higher than the second predetermined pressure P2 which is the forced regeneration start pressure.

Instead of the target rotation speed indicated by the engine control dial 2, the command rotation number finally sent to the electronic governor 1a or the actual rotation number detected by the rotation detection device 3 may be used.

In this embodiment configured as described above, even when the sub operating state of all the operating means is detected by the detection signal of the pressure detecting device 35 and the sub operating state continues for the predetermined time, the engine control dial 2 When the instructed target rotation speed is not higher than the predetermined rotation speed Na for regeneration, the forced regeneration is not started, so that an unintentional rise in the engine speed is prevented, and reproduction can be performed without giving the operator an uncomfortable feeling .

In many cases, a construction machine such as a hydraulic excavator performs an auto idle control. The auto-idle control is a control for automatically reducing the number of revolutions of the engine 1 to a low number of revolutions when the sub-operating state of the entire operating means continues for a predetermined time (for example, about 10 seconds).

In the case where the exhaust gas purifying system of this embodiment is applied to a machine equipped with such an auto idle control system, since the predetermined time (for example, 5 minutes) of the sub operating state monitored by the control of the present embodiment is longer, The rotational speed of the engine 1 is lowered to the low rotational speed before the forced regeneration is started by the exhaust gas purifying system of the embodiment.

In this case, when the forced regeneration is initiated against the intention of the present embodiment, an unintended rise of the engine speed occurs. Therefore, when the exhaust gas purifying system of the present embodiment is applied to a model equipped with an auto idle control system, the setting of the auto idle mode is set to off by the operator's choice.

It is to be understood that the present invention is not limited to the specific exemplary embodiments described above and that various modifications may be made by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims. And such modified embodiments are within the scope of the claims of the present invention.

1: Diesel engine 1a: Electronic governor
2: Engine control dial 3: Rotational speed detection device
4: Controller 5: Key switch
11: Hydraulic pump 12: Pilot pump
13: Hydraulic motor 14, 15: Hydraulic cylinder
17 to 19: Flow control valve 20: Pilot hydraulic pressure source
21: Pilot relief valve 23: Electromagnetic switch valve
24: Pilot flow path 25, 26, 27: Remote controller valve
28, 29: Operation lever 31: Exhaust pipe
32: Filter 33: Oxidation catalyst
34: DPF device 35: pressure detecting device
36: differential pressure detecting device 37: exhaust temperature detecting device
38: display device (monitor) 38a: display screen
39: fuel injector for regeneration 40: shuttle valve group
41 to 46: Shuttle valve 100: Lower traveling body
* 101: Upper turning body 102: Front working machine
104a, 104b: traveling motor 105: pivoting motor
106: engine room 107: cab
111: Boom 112:
113: Bucket 114: Boom cylinder
115: arm cylinder 116: bucket cylinder

Claims (8)

1. An exhaust gas purifying system for a construction machine, comprising: a diesel engine; a plurality of driven members driven by a power of the engine; and operating means for instructing operations of the plurality of driven members,
A filter disposed in an exhaust system of the engine for trapping particulate matter contained in the exhaust gas;
A regeneration device for burning particulate matter deposited on the filter to burn off the particulate matter to regenerate the filter,
Operation detecting means for detecting presence / absence of operation of the operating means,
And a regeneration control device for operating the regenerating device when the sub operating state of the operating means is detected by the operation detecting means and the sub operating state continues for a predetermined time, . The method according to claim 1,
Wherein the regeneration control device stops the operation of the regeneration device when an operation of the operation device is detected by the operation detection device during operation of the regeneration device. The method according to claim 1,
The engine further includes target rotation speed command means for commanding a target rotation speed,
Wherein the regeneration control device stops the operation of the regeneration device when the target revolving speed commanded by the target revolving speed command means is changed during operation of the regeneration device. The method according to claim 1,
Further comprising a pressure detecting device for detecting a pressure loss of the filter,
The playback control device includes:
And stops the operation of the regeneration device when the pressure loss detected by the pressure detection device becomes lower than the first predetermined pressure value. The method according to claim 1,
Further comprising a pressure detecting device for detecting a pressure loss of the filter,
The playback control device includes:
When the operating state of the operating means is detected by the operation detecting means and the sub operating state continues for a predetermined time and the pressure loss detected by the pressure detecting device is higher than the second predetermined pressure value, The exhaust gas purifying system of the construction machine. The method according to claim 1,
Wherein the regeneration control device is configured to control the regeneration device to regenerate the engine when the sub operating state of the operating means is detected by the operation detecting device and the sub operating state continues for a predetermined time to operate the regenerating device, Wherein the control unit controls the exhaust gas purifying system of the construction machine. The method according to claim 1,
Further comprising: target revolution speed command means for commanding a target revolution speed of the engine,
Wherein the regeneration control device is configured to perform the regeneration control of the regeneration control device when the operating state of the operating means is detected by the operation detecting means and the sub operating state continues for a predetermined time and the target rotational speed commanded by the target rotational speed command means is a predetermined rotational speed The control device activates the regenerating device when the temperature of the exhaust gas is higher than the predetermined temperature. The method according to claim 1,
Wherein the regeneration device has an oxidation catalyst disposed upstream of the filter and a fuel supply means for supplying fuel to the oxidation catalyst, wherein the exhaust gas of the engine is forcibly heated to a temperature higher than an activation temperature of the oxidation catalyst The fuel is supplied from the fuel supply means to the oxidation catalyst to raise the temperature of the exhaust gas by the heat of reaction between the fuel and the oxidation catalyst so as to incinerate and remove the particulate matter deposited on the filter Exhaust gas purification system of construction machinery.






KR1020130004050A 2013-01-14 2013-01-14 Exhaust purification system for construction machine KR20140093322A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019138183A (en) * 2018-02-07 2019-08-22 住友重機械建機クレーン株式会社 Working machine
CN110985474A (en) * 2019-12-30 2020-04-10 三一重机有限公司 Hydraulic control system and control method for engineering machinery and engineering machinery

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019138183A (en) * 2018-02-07 2019-08-22 住友重機械建機クレーン株式会社 Working machine
CN110985474A (en) * 2019-12-30 2020-04-10 三一重机有限公司 Hydraulic control system and control method for engineering machinery and engineering machinery

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