JP5623341B2 - Regeneration control device for exhaust gas aftertreatment device of hydraulic work machine - Google Patents

Description

  The present invention relates to a regeneration control device for an exhaust gas post-treatment device of a hydraulic work machine that is provided in a hydraulic work machine equipped with a diesel engine and removes particulate matter accumulated in the exhaust gas post-treatment device.

   In order to meet exhaust gas regulations that have been tightened year by year, it has become necessary to install exhaust gas purification devices on construction machines using diesel internal combustion engines. One of the exhaust gas purification devices is an exhaust gas post-treatment device that is mounted downstream of the exhaust path and purifies the exhaust gas by collecting particulate matter that is subject to exhaust gas regulation with a filter. This exhaust gas after-treatment device is configured by a filter part with catalyst for capturing particulate matter in exhaust gas exhausted from the engine, and a diesel oxidation catalyst installed upstream of the filter part. The main component of particulate matter is carbon generated when diesel oil burns in the engine. When the exhaust gas temperature rises, the particulate matter collected in the filter with catalyst reacts with oxygen and hydrogen contained in the exhaust gas. Regeneration is performed, which is decomposed into water and carbon dioxide and removed from the filter with catalyst.

  Due to the effect of the catalyst supported on the filter, it is possible to react and regenerate at a lower temperature as compared with the case where the catalyst is not supported. The filter with catalyst installed in the exhaust gas aftertreatment device has a limit on the amount of particulate matter that can be collected, and it is necessary to periodically remove (regenerate) the particulate matter to recover the exhaust gas purification function. . When performing regeneration to remove particulate matter collected by the exhaust gas after-treatment device and restore its function, an exhaust gas temperature above a certain level is required, but the exhaust gas temperature generated from a diesel internal combustion engine Since the temperature reaches a temperature at which regeneration is performed only in a limited state such as when the engine is under a high load, the amount of particulate matter gradually increases in proportion to the operating time. Therefore, in order to force regeneration, it is necessary to arbitrarily raise the exhaust gas temperature. In order to recover the exhaust gas purification function, unburned diesel oil is sprayed onto the diesel oxidation catalyst installed upstream of the filter with catalyst to cause an oxidation reaction by the function of the supported catalyst, and the reaction heat is used. Thus, it is possible to forcibly perform regeneration by raising the temperature of exhaust gas passing through the filter with catalyst. As a condition for this, the exhaust gas needs a certain temperature or higher for activating the oxidation catalyst. As a method for increasing the temperature by applying a load to the engine in order to increase the exhaust gas temperature, the method of Patent Document 1 is known. And by controlling the hydraulic pump as described in Patent Document 1, the hydraulic oil pressure and hydraulic oil flow rate are increased, the engine is loaded, the exhaust gas temperature is raised to the catalyst activation temperature, and an oxidation reaction is caused. To play.

Japanese Patent No. 3073380

 Since the exhaust gas temperature does not rise to the oxidation catalyst activation temperature when idling or under a low load, it is necessary to increase the exhaust gas temperature by applying a load to the engine as described above. In the technique described in Patent Document 1, the hydraulic pump pressure and flow rate for applying a predetermined engine load are set in advance, and the temperature is raised to an exhaust gas temperature for normal regeneration under a normal working environment. However, since the exhaust gas temperature is closely related to the outside air temperature, when regeneration is performed when the outside air temperature is low, the exhaust temperature is determined by the hydraulic oil pressure and hydraulic oil flow set in advance. There is a possibility that the exhaust gas cannot be sufficiently raised and the regeneration cannot be performed. Conversely, when the outside air temperature is high, the exhaust gas temperature increases excessively, which may adversely affect fuel consumption.

  In order to solve the above-described problem, a regeneration control device for an exhaust gas aftertreatment device of a hydraulic work machine according to the present invention is configured to connect an engine and particulate matter contained in the exhaust gas connected to an exhaust port of the engine. An exhaust gas aftertreatment device to be removed, a hydraulic pump driven by the engine, and either or both of a discharge pressure and a discharge flow rate of hydraulic oil discharged from the hydraulic pump are controlled simultaneously in the engine. Hydraulic work machine comprising load control means for controlling the magnitude of the acting load, and regeneration control means for controlling the load control means and burning and removing the particulate matter deposited on the exhaust gas aftertreatment device In the regeneration control device for the exhaust gas aftertreatment device of the present invention, the regeneration control device further comprises temperature detection means for detecting a temperature related to the outside air temperature, and the regeneration control means is a negative controller that acts on the engine. There is obtained a configuration which controls the magnitude of the load acting on the engine by the load control means based on the temperature detected by said temperature detecting means so that the required torque needed to play.

  Further, as the temperature detection means for detecting the temperature related to the outside air temperature, the load control means can be controlled using the intake air temperature or exhaust temperature of the engine.

  Further, as load control means for controlling the magnitude of the load acting on the engine, the hydraulic pump is a variable displacement hydraulic pump, and includes a tilt angle control means for controlling the tilt angle of the variable displacement hydraulic pump, The load control means includes a discharge pressure control means for controlling the hydraulic fluid flow discharged by controlling the tilt angle by the tilt angle control means or controlling the hydraulic oil pressure discharged from the hydraulic pump. The load control means can control using either or both of controlling the hydraulic pressure by controlling the discharge pressure control means.

  A regeneration control device for an exhaust gas aftertreatment device of a hydraulic work machine according to the present invention is the invention according to claim 1, wherein when the exhaust gas aftertreatment device is regenerated, the outside air temperature closely related to the exhaust gas temperature. Because the engine can be loaded with the required torque required for regeneration according to the temperature related to the engine, the exhaust gas temperature can be raised sufficiently even when the outside air temperature is low, and regeneration is performed reliably. It is possible to increase the engine output before the limit of the amount of particulate matter accumulated in the filter to raise the exhaust gas temperature, burn off the particulate matter in the filter, and cause the engine to increase due to excessive exhaust resistance. It is possible to suppress malfunctions and to maintain the functions of the exhaust gas aftertreatment device and prevent failure. In addition, when the outside air temperature is high, the exhaust gas temperature rises excessively and does not adversely affect fuel consumption.

 The invention according to claim 2 is more accurate by using the intake air temperature that directly affects the exhaust gas temperature as the temperature related to the outside air temperature, and in the intake passage where the rapid temperature change is small. By installing the sensor, a system capable of more stable control can be constructed.

 The invention according to claim 3 can change the engine load at any time by directly detecting the exhaust gas temperature necessary for recovering the function of the exhaust gas aftertreatment device using the exhaust gas temperature as the temperature related to the outside air temperature. Therefore, control without excess or deficiency can be performed, and fuel consumption can be minimized.

 In the invention according to claim 4, in order to control the exhaust gas temperature, the tilting angle control of the variable displacement hydraulic pump is performed to change the hydraulic oil flow rate, so that the engine load is not increased. Can be applied to hydraulic equipment that does not have a mechanism capable of changing pressure, such as a hydraulic control valve, and in hydraulic construction machines, etc., the hydraulic actuator is safe without unintended movement of the operator. Excellent.

  The invention according to claim 5 does not have a hydraulic oil flow variable mechanism such as a gear pump or the like when the driving force of the hydraulic pump is constant rotation, for example, by changing the hydraulic oil pressure to control the exhaust gas temperature. The engine load can be changed even for hydraulic equipment.

1 is a configuration diagram of a work machine according to a first embodiment of the present invention. It is a graph of the relationship between the outside air temperature in a steady state and the torque required for regeneration in the present invention. It is a flowchart which shows the operation | movement procedure of the control apparatus mounted in the working machine which concerns on the 1st Embodiment of this invention. It is a block diagram of the working machine which concerns on the 2nd Embodiment of this invention. It is a block diagram of the working machine which concerns on the 3rd Embodiment of this invention. It is a graph of the relationship between the outside air temperature and the exhaust gas temperature in a steady state in the present invention. It is a flowchart which shows the operation | movement procedure of the control apparatus mounted in the working machine which concerns on the 3rd Embodiment of this invention.

<First Embodiment>
A first embodiment of a regeneration control device for an exhaust gas aftertreatment device of a hydraulic construction machine according to the present invention will be described with reference to FIGS. FIG. 1 shows a configuration diagram according to a first embodiment of a regeneration control device for an exhaust gas aftertreatment device of a hydraulic construction machine, and FIG. 2 shows a relationship between an outside air temperature and an engine torque used in the regeneration control device. FIG. 3 is a control flowchart. In FIG. 1, 1 is an engine, 2 is a variable displacement hydraulic pump driven by the engine 1, 3 is a regulator for controlling the flow rate of hydraulic oil discharged from the hydraulic pump 2, and 4 is a controller for controlling the regulator 3 and the like. . An exhaust gas aftertreatment device 5 is connected downstream of the exhaust path of the engine 1. The exhaust gas after-treatment device 5 is composed of an oxidation catalyst 6 that oxidizes unburned fuel to generate heat and a filter 7 with a catalyst that collects and removes particulate matter in the exhaust gas. 8 is a hydraulic equipment control valve that controls the flow of hydraulic oil discharged from the hydraulic pump 2 to operate hydraulic equipment such as a hydraulic cylinder and a traveling motor provided in the construction machine. Reference numeral 9 denotes a hydraulic pressure adjusting valve built in the hydraulic equipment control valve 8, which is operated to restrict the hydraulic circuit and raise the pressure in the circuit to increase the hydraulic oil pressure P. Reference numeral 10 is a hydraulic oil tank, and 11 is an outside air temperature sensor that detects the outside air temperature ti and sends a temperature signal a to the controller 4. A regeneration switch 12 outputs a regeneration control command signal to the controller 3.

  The controller 4 stores a control table 4a as shown in FIG. This control table 4a shows the relationship between the outside air temperature ti detected by the outside air temperature sensor 11 and the load applied to the engine 1, and the exhaust gas temperature reaches the oxidation catalyst activation temperature t at a predetermined engine speed. The engine load (required torque) is obtained by experiment for each outside air temperature. In this control table 4a, when the outside air temperature ti is equal to or higher than the temperature t2 (ti> = t2), the necessary torque T acting on the engine 1 is constant at T2, but this torque T2 is the hydraulic pump 2 When the outside air temperature ti is equal to or higher than the temperature t2, the exhaust gas temperature reaches the oxidation catalyst activation temperature t by the minimum driving torque T2. Therefore, when the outside air temperature is equal to or higher than t2, the exhaust gas temperature is a temperature necessary for regeneration. On the other hand, when the outside air temperature is less than t2, the necessary torque T increases as the temperature decreases. For example, when the outside air temperature is t1, the exhaust gas temperature becomes the oxidation catalyst activation temperature t when the necessary torque T1 (T1> T2). To reach.

  The required torque T can be increased by increasing the hydraulic oil pressure P by the hydraulic pressure adjusting valve 9 and increasing the hydraulic oil flow rate Q by the regulator 3, thereby controlling the required torque T. One of the control of the operating pressure P by the hydraulic pressure adjusting valve 9 and the control of the operating flow rate Q by the regulator 3 may be used.

  Next, reproduction control based on the processing of the controller 4 will be described using the control flowchart shown in FIG.

  When it is notified by the monitor (not shown) that the reproduction is necessary, the operator instructs the reproduction control by the reproduction switch 12. (Manual regeneration) When regeneration control is started, the outside air temperature ti (procedure S-1) detected by the outside air temperature sensor 11 is transmitted to the controller 4 as a temperature signal a. It is determined whether or not the outside temperature ti at that time is the exhaust gas temperature necessary for regeneration (step S-2), and if the outside temperature satisfies the condition, the regeneration is executed as it is. The temperature condition at this time is, for example, a case where the outside air temperature ti is equal to or greater than t2 (ti> = t2), and regeneration at this time is performed without applying a hydraulic load to the engine 1 (minimum driving torque T2). ) To increase the exhaust gas temperature upstream of the filter with catalyst 7 by injecting unburned fuel into the oxidation catalyst 6. On the other hand, when it is determined that the outside air temperature ti is insufficient for regeneration, for example, when the outside air temperature ti is t1 (t1 <t2), the necessary torque T1 corresponding to the detected outside air temperature t1 is set. Obtained from the control table 4a, the hydraulic oil pressure P and the hydraulic oil flow rate Q are controlled so that the load acting on the engine 1 becomes the required torque T1. This control is based on the relationship between the hydraulic oil pressure P and the hydraulic oil flow rate Q set in advance in relation to the required torque T, and the control signal b is sent from the controller 4 to the hydraulic pressure adjusting valve 9 and the control signal c is sent to the regulator 3. This is done by outputting. Then, the controller 4 obtains the hydraulic oil pressure P1 and the hydraulic oil flow rate Q1 corresponding to the required torque T1 with respect to the outside air temperature t1, and supplies the hydraulic control valve 9 with the control signal b1 corresponding to the hydraulic oil pressure P1 and hydraulic oil flow rate Q1. The control signal c1 is output to the regulator 3, and the hydraulic pressure adjusting valve 9 that receives the control signal b1 throttles the hydraulic circuit, controls the hydraulic oil pressure P to be increased to a predetermined value P1, and the regulator 3 that receives the control signal c By changing the pump tilt angle of the hydraulic pump 2 to increase the hydraulic oil flow rate Q to a predetermined value Q1, the load on the engine is increased, the exhaust gas temperature is increased (step S-3), and regeneration is performed. This regeneration is performed by the above-described injection of unburned fuel into the oxidation catalyst 6 and an increase in exhaust gas temperature due to a load increase of the engine 1. The hydraulic oil discharged from the hydraulic pump 2 returns to the hydraulic oil tank 10 via the hydraulic pressure adjustment valve 9. By using the temperature signal a from the outside air temperature sensor 11, it is possible to construct a system that can react sensitively to the external environment.

<Second Embodiment>
FIG. 4 shows a configuration diagram of a work machine according to the second embodiment. Reference numeral 13 denotes an intake port of the engine 1, 14 denotes an intake sensor provided in the intake port 13, and other reference numerals are indicated in the portions corresponding to FIG. 1 described above.

  In this embodiment, the load on the engine 1 for obtaining the exhaust gas temperature necessary for regeneration is determined based on the outside air temperature ti detected by the outside air temperature sensor 11 in the first embodiment. Instead of the air temperature sensor 11, a load to be applied to the engine at the time of regeneration is determined based on the temperature signal d of the intake air temperature tk detected by the intake air temperature sensor 14. Since the intake air temperature is the air temperature immediately before being sucked into the engine, it is possible to control the state of exhaust gas exhausted from the engine 1 more stably than the outside air temperature.

<Third Embodiment>
FIG. 5 shows a configuration diagram of a work machine according to the third embodiment. Reference numeral 15 denotes an exhaust gas temperature sensor provided in, for example, an upstream exhaust pipe of the exhaust gas aftertreatment device 5, and detects the exhaust gas temperature tc. Other reference numerals are the same as those shown in FIG. 1 described above.

 In the present embodiment, based on the outside air temperature detected by the outside air temperature sensor 11 in the first embodiment, and on the basis of the intake air temperature of the engine 1 detected by the intake air temperature sensor 14 in the second embodiment. Thus, the load of the engine 1 for obtaining the exhaust gas temperature necessary for the regeneration has been determined. However, as shown in FIG. 6, it is confirmed that the exhaust gas temperature tc and the outside air temperature ti are correlated. Therefore, instead of them, the load acting on the engine at the time of regeneration is determined based on the temperature signal e of the exhaust gas temperature tc detected by the exhaust temperature sensor 15.

  Next, the reproduction control in the present embodiment will be described with reference to the control flowchart shown in FIG. When the regeneration switch 12 is operated, the exhaust gas temperature sensor 15 detects the exhaust gas temperature tc (step S-4), and the temperature signal e is transmitted to the controller 4. Then, it is determined whether or not the detected temperature tc is equal to or higher than the catalyst activation temperature t of the oxidation catalyst 6. (Tc> = t) (procedure S-5). Here, when the exhaust gas temperature tc is lower than the catalyst activation temperature t, the control signal b is sent from the controller 4 to the hydraulic pressure adjusting valve 9 in order to increase the exhaust gas temperature tc up to the catalyst activation temperature t. Is output, the hydraulic oil pressure P is set to Pc, the control signal c is output to the regulator 3, and the hydraulic oil flow rate Q is controlled to Qc.

  In the second embodiment, the exhaust gas temperature necessary for detecting the intake air temperature tk of the engine 1 and determining whether or not the exhaust gas temperature is insufficient is determined. However, the exhaust gas temperature sensor 15 detects the exhaust gas temperature tc. As a result, the necessary exhaust gas temperature can be monitored even when regeneration is performed during operation, so that appropriate regeneration can be performed. In addition, since it is possible to directly determine whether regeneration is possible, feedback control is possible, and the hydraulic control valve 9 and the regulator 3 can be controlled more accurately.

DESCRIPTION OF SYMBOLS 1 Engine 2 Hydraulic pump 3 Regulator 4 Controller 4a Control table 5 Exhaust gas aftertreatment device 6 Oxidation catalyst 7 Filter with catalyst 8 Hydraulic equipment control valve 9 Hydraulic adjustment valve 10 Hydraulic oil tank 11 Outside air temperature sensor 12 Regeneration switch 13 Inlet 14 Intake Air temperature sensor 15 Exhaust temperature sensor

Claims (5)

An engine, an exhaust gas aftertreatment device that is connected to an exhaust port of the engine and removes particulate matter contained in the exhaust gas, a hydraulic pump driven by the engine, and hydraulic oil discharged from the hydraulic pump A load control means for controlling the magnitude of the load acting on the engine by simultaneously controlling either one or both of the discharge pressure and the discharge flow rate of the engine, and controlling the load control means, and the exhaust gas aftertreatment device In a regeneration control device for an exhaust gas aftertreatment device of a hydraulic work machine, comprising a regeneration control means for burning and removing the particulate matter deposited on
Temperature detection means for detecting a temperature related to the outside air temperature, and the regeneration control means is based on a temperature detected by the temperature detection means so that a load acting on the engine becomes a necessary torque necessary for regeneration. A regeneration control device for an exhaust gas aftertreatment device of a hydraulic work machine, wherein the load control means controls the magnitude of a load acting on the engine.   The regeneration control device for an exhaust gas aftertreatment device of a hydraulic work machine according to claim 1, wherein the temperature detection means is an intake air temperature sensor that detects a temperature taken into the engine.   The regeneration control device for an exhaust gas aftertreatment device of a hydraulic work machine according to claim 1, wherein the temperature detection means is an exhaust temperature sensor that detects the temperature of the exhaust gas of the engine.   The hydraulic pump is a variable displacement hydraulic pump, and includes a tilt angle control unit that controls a tilt angle of the variable displacement hydraulic pump, and the load control unit sets the tilt angle by the tilt angle control unit. The regeneration control device for an exhaust gas aftertreatment device of a hydraulic work machine according to any one of claims 1 to 3, wherein the discharge flow rate is controlled. A discharge pressure control means for controlling the discharge pressure of the hydraulic oil discharged from the hydraulic pump;
The regeneration of the exhaust gas aftertreatment device of the hydraulic work machine according to any one of claims 1 to 3, wherein the load control unit controls the discharge pressure control unit to control the discharge pressure. Control device.

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