JP2011231737A - Exhaust emission control system for engine-driven machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the execution of a high precision work executed based upon engine sound in an exhaust emission control system for an engine-driven machine 220.SOLUTION: The exhaust emission control system for the engine-driven machine 220 includes: an engine 70 that is mounted in the engine-driven machine 220; an exhaust emission control device 50 disposed in an exhaust gas line 77 of the engine 70; and recovery devices 70, 81, 82, 117 for combustion removing particulate matter in the exhaust emission control device 50. During operations of operation unit 235, 236 for a work unit 227 provided at the engine-driven machine 220, the recovery devices 70, 81, 82, 117 are not actuated irrespective of the level of clogging of the exhaust emission control device 50.

Description

  The present invention relates to an exhaust gas purification system for work machines such as construction machines, agricultural machines, and engine generators.

  In recent years, as high-level exhaust gas regulations related to diesel engines (hereinafter simply referred to as engines) have been applied, air pollutants in exhaust gas have been introduced into construction machines, agricultural machines, and engine generators on which engines are mounted. There has been a demand for mounting an exhaust gas purification device for purification treatment. A diesel particulate filter (hereinafter referred to as DPF) is known as an exhaust gas purification device (see Patent Documents 1 and 2). The DPF is for collecting particulate matter (hereinafter referred to as PM) in the exhaust gas. In this case, if the PM collected by the DPF exceeds a specified amount, the flow resistance in the DPF increases and the engine output decreases, so the PM accumulated in the DPF is removed by the temperature rise of the exhaust gas, It is often performed to recover the PM collection ability of the DPF (regenerate the DPF).

JP 2000-145430 A Japanese Patent Laid-Open No. 2003-27922

  When regenerating the DPF in the conventional configuration, the engine throttle is increased by closing the intake throttle device or the exhaust throttle device to a predetermined opening and limiting the intake / exhaust amount. The fuel consumption is increased beyond the amount of operation of an accelerator operating tool such as a throttle lever or an accelerator pedal, and the engine output (rotation speed and torque) is increased. As a result, the exhaust gas temperature from the engine increases (thermal energy is given to the exhaust gas).

  However, when the DPF is regenerated, there is a problem in that the operator feels uncomfortable because an impact or a change in engine sound occurs due to a change in engine output. In addition, the possibility that an operator mistakes a sudden impact or a change in engine sound as an abnormality cannot be denied. In addition, since DPF regeneration using an intake throttle device or an exhaust throttle device requires a relatively long time (for example, about 30 minutes), the precise operation can be performed using the engine sound. In many construction machines, it is not preferable from the viewpoint of workability that engine output and engine sound change frequently occur over a long period of time.

  Therefore, the present invention has a technical problem to provide an exhaust gas purification system for a working machine that has been improved by examining the current situation.

  An exhaust gas purification system for a work machine according to a first aspect of the present invention includes an engine mounted on the work machine, an exhaust gas purification device disposed in an exhaust system of the engine, and particulate matter in the exhaust gas purification device A regenerator for burning and removing the exhaust gas so that the regenerator is not operated during operation of the operating means for the working unit provided in the working machine regardless of the clogged state of the exhaust gas purification device. It is said that it is comprised.

  According to a second aspect of the present invention, in the exhaust gas purification system for a working machine according to the first aspect, the regeneration that operates when the regeneration device is not operated under the condition that the clogged state of the exhaust gas purification device is equal to or higher than a specified level. The prohibition notification means is provided.

  According to a third aspect of the present invention, in the exhaust gas purification system for a working machine according to the first or second aspect, after the operation of the operation means is completed under the condition that the clogged state of the exhaust gas purification device is not less than a specified level. When a predetermined time elapses in a non-operating state, the operation prohibition of the playback device is released.

  According to invention of Claim 1, the engine mounted in a working machine, the exhaust gas purification apparatus arrange | positioned in the exhaust system of the engine, and the regeneration apparatus for carrying out the combustion removal of the particulate matter in the said exhaust gas purification apparatus And during operation of the operating means for the working unit provided in the working machine, the regeneration device is configured not to operate regardless of the clogged state of the exhaust gas purification device. By operating the operating means for the working unit, the regeneration operation of the exhaust gas purification device can be prohibited. That is, the regeneration operation of the exhaust gas purification device can be prohibited by the operator's intention according to the working state of the working machine. For this reason, while the regeneration control for recovering the particulate matter collecting ability of the exhaust gas purifying apparatus can be executed, the precise operation performed by the operator relying on the engine sound can be smoothly performed. That is, there is an effect that the defect of the regeneration operation of the exhaust gas purification device that may hinder the precise work can be eliminated.

  According to a second aspect of the present invention, in the exhaust gas purification system for a working machine according to the first aspect, the system operates when the regeneration device is not operated under a condition that the clogged state of the exhaust gas purification device is equal to or higher than a specified level. Since the regeneration prohibition notification means is provided, the fact that the regeneration operation of the exhaust gas purifying device is prohibited is notified by the notification of the regeneration prohibition notification means while operating the operation means for the working unit. It is possible to appeal to the visual sense of the operator, and it is possible to reliably call the operator's attention. By checking the state of the reproduction prohibition notification means, it can be easily confirmed whether or not reproduction is prohibited.

  According to a third aspect of the present invention, in the exhaust gas purification system for a working machine according to the first or second aspect, after the operation of the operation means is completed under the condition that the clogged state of the exhaust gas purification device is not less than a specified level. Since the prohibition of the operation of the regenerator is canceled when a predetermined time elapses in a non-operating state, the exhaust gas purification device regenerating operation is performed as soon as the operation of the operating means is finished. The exhaust gas purification device regeneration operation is performed after a certain period of time has passed. For this reason, there is an effect that it is possible to smoothly shift to the regeneration operation of the exhaust gas purification device while reducing the uncomfortable feeling to the operator as much as possible.

It is a side view of a forklift car equipped with an engine. It is a top view of a forklift car. It is fuel system explanatory drawing of an engine. It is a functional block diagram which shows the relationship between an engine and an exhaust gas purification apparatus. It is a figure explaining the injection timing of fuel. It is explanatory drawing of an output characteristic map. It is explanatory drawing of an instrument panel. It is a flowchart which shows the flow of DPF regeneration control. It is a flowchart which shows an interruption process. It is a side view of a backhoe carrying an engine. It is a top view of a backhoe. It is a flowchart which shows the flow of DPF regeneration control at the time of mounting an engine on a backhoe. It is a flowchart which shows the interruption process at the time of mounting an engine in a backhoe.

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

(1). Schematic Structure of Forklift Car First, the schematic structure of a forklift car 220 that is an example of a working machine on which the engine 70 is mounted will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, the forklift car 220 includes a traveling machine body 224 having a pair of left and right front wheels 222 and a rear wheel 223. The traveling body 224 is equipped with a control unit 225 and an engine 70. The engine 70 is a four-cylinder type diesel engine. The engine 70 is covered from above with a cover body 233, and a control unit 225 is provided on the cover body 233.

  A working unit 227 having a fork 226 for cargo handling work is provided on the front side of the traveling machine body 224. On the rear side of the traveling machine body 224, a counterweight 231 for balancing the weight with the working unit 227 is provided. The control unit 225 is provided with a control seat 228 on which an operator is seated, a control handle 229, and a fork lift lever 235 and a tilt lever 236 (tilt lever) which are operating means for the working unit 227. A fork 226 is mounted on the mast 230, which is a component of the working unit 227, so as to be movable up and down. By operating the fork elevating lever 235 to move the fork 226 up and down, a pallet (not shown) loaded with a load is placed on the fork 226 and the traveling machine body 224 is moved forward and backward to carry a cargo handling operation such as transporting the pallet. Is configured to run. The tilt lever 236 is used to change the vertical tilt angle of the fork 226 by tilting the mast 236.

  The flywheel housing 78 of the engine 70 is positioned on the front side of the traveling machine body 224, and the cooling fan 76 is positioned on the rear side of the traveling machine body 224. In other words, the engine 70 is arranged so that the direction of the crankshaft in the engine 70 is along the alignment direction (front-rear direction) of the working unit 227 and the counterweight 231. The engine 70 is supported on the engine mounting chassis 84 of the traveling machine body 224 by vibration isolation via the engine legs 83. A mission case 232 is connected to the front side of the flywheel housing 78. Rotational power from the engine 70 via the flywheel 79 is appropriately shifted in the transmission case 232 and transmitted to the hydraulic drive sources of the front and rear wheels 222 and 223 and the fork 226.

  An engine cooling radiator 234 is opposed to the cooling fan 76 at a high position near the counterweight 231 between the control seat 228 and the counterweight 231 disposed behind the control seat 228 in the cover 233. Are arranged as follows. By blowing cooling air to the radiator 234 by the rotation drive of the cooling fan 76, the radiator 234 is air-cooled. As shown in FIG. 1, since the radiator 234 is disposed at a high position near the counterweight 231, a space is provided below the radiator 234 and the cooling fan 76. In this space, a diesel particulate filter 50 (hereinafter referred to as DPF), which is an example of an exhaust gas purification device, is accommodated so as to face an oil pan 81 disposed on the lower surface side of the engine 70.

(2). Next, the engine 70 mounted on the work machine (forklift car 220) and the surrounding structure will be described with reference to FIGS. 3 and 4. FIG. As shown in FIG. 4, the engine 70 of the embodiment includes a cylinder block 75 having a cylinder head 72 fastened to the upper surface. An intake manifold 73 is connected to one side of the cylinder head 72, and an exhaust manifold 71 is connected to the other side. A common rail system 117 that supplies fuel to each cylinder of the engine 70 is provided below the intake manifold 73 on the side surface of the cylinder block 75. An intake pipe 76 connected to the intake upstream side of the intake manifold 73 is connected to an intake throttle device 81 and an air cleaner (not shown) for adjusting the intake pressure (intake amount) of the engine 70.

  As shown in FIG. 3, a fuel tank 118 is connected to the injectors 115 for four cylinders in the engine 70 via a common rail system 117 and a fuel supply pump 116. Each injector 115 is provided with an electromagnetic switching control type fuel injection valve 119. The common rail system 117 includes a cylindrical common rail 120. A fuel tank 118 is connected to the suction side of the fuel supply pump 116 via a fuel filter 121 and a low pressure pipe 122. The fuel in the fuel tank 118 is sucked into the fuel supply pump 116 via the fuel filter 121 and the low pressure pipe 122. The fuel supply pump 116 of the embodiment is disposed in the vicinity of the intake manifold 73. On the other hand, a common rail 120 is connected to the discharge side of the fuel supply pump 116 via a high-pressure pipe 123. The common rail 120 is connected to injectors 115 for four cylinders via four fuel injection pipes 126.

  In the above configuration, the fuel in the fuel tank 118 is pumped to the common rail 120 by the fuel supply pump 116, and high-pressure fuel is stored in the common rail 120. Each fuel injection valve 119 is controlled to open and close, whereby high-pressure fuel in the common rail 120 is injected from each injector 115 to each cylinder of the engine 70. That is, by electronically controlling each fuel injection valve 119, the injection pressure, injection timing, and injection period (injection amount) of the fuel supplied from each injector 115 are controlled with high accuracy. Therefore, nitrogen oxide (NOx) from the engine 70 can be reduced, and noise and vibration of the engine 70 can be reduced.

  As shown in FIG. 5, the common rail system 117 is configured to execute the main injection A near the top dead center (TDC). In addition to the main injection A, the common rail system 117 executes a small amount of pilot injection B for the purpose of reducing NOx and noise at the time of the crank angle θ1 about 60 ° before the top dead center, Pre-injection C is executed for the purpose of noise reduction immediately before the crank angle θ2, and particulate matter (hereinafter referred to as PM) is reduced and exhaust gas is emitted at the crank angles θ3 and θ4 after top dead center. The after-injection D and the post-injection E are executed for the purpose of promoting purification.

  As shown in FIG. 3, a fuel supply pump 116 is connected to the fuel tank 118 via a fuel return pipe 129. A common rail return pipe 131 is connected to the end of the cylindrical common rail 120 in the longitudinal direction via a return pipe connector 130 that limits the pressure of fuel in the common rail 120. That is, surplus fuel from the fuel supply pump 116 and surplus fuel from the common rail 120 are collected in the fuel tank 118 via the fuel return pipe 129 and the common rail return pipe 131.

  An exhaust pipe 77 connected to the exhaust downstream side of the exhaust manifold 71 is connected to an exhaust throttle device 82 for adjusting the exhaust pressure of the engine 70 and a DPF 50 which is an example of an exhaust gas purification device. Exhaust gas discharged from each cylinder to the exhaust manifold 71 is purified through the exhaust pipe 77, the exhaust throttle device 82, and the DPF 50, and then released to the outside.

  The DPF 50 is for collecting PM or the like in the exhaust gas. The DPF 50 according to the embodiment is configured by accommodating a diesel oxidation catalyst 53 such as platinum and a soot filter 54 in series in a substantially cylindrical filter case 52 in a casing 51 made of a refractory metal material. In the embodiment, the diesel oxidation catalyst 53 is disposed on the exhaust upstream side of the filter case 52, and the soot filter 54 is disposed on the exhaust downstream side. The soot filter 54 has a honeycomb structure having a large number of cells partitioned by porous (filterable) partition walls.

  In one side portion of the casing 51, an exhaust introduction port 55 communicating with the exhaust downstream side of the exhaust throttle device 82 in the exhaust pipe 77 is provided. One end of the casing 51 is closed by a first bottom plate 56, and one end of the filter case 52 facing the first bottom plate 56 is closed by a second bottom plate 57. The annular gap between the casing 51 and the filter case 52 and the gap between the bottom plates 56 and 57 are filled with a heat insulating material 58 such as glass wool so as to surround the diesel oxidation catalyst 53 and the soot filter 54. ing. The other side of the casing 51 is closed by two lid plates 59 and 60, and a substantially cylindrical exhaust outlet 61 passes through both the lid plates 59 and 60. In addition, a resonance chamber 63 that communicates with the inside of the filter case 52 via a plurality of communication pipes 62 is provided between the lid plates 59 and 60.

  An exhaust gas introduction pipe 65 is inserted into an exhaust introduction port 55 formed on one side of the casing 51. The tip of the exhaust gas introduction pipe 65 projects across the casing 51 to the side surface opposite to the exhaust introduction port 55. A plurality of communication holes 66 opening toward the filter case 52 are formed on the outer peripheral surface of the exhaust gas introduction pipe 65. A portion of the exhaust gas introduction pipe 65 that protrudes from the side surface opposite to the exhaust introduction port 55 is closed by a lid 67 that is detachably screwed to the portion.

  The DPF 50 is provided with a DPF temperature sensor 26 that detects an exhaust gas temperature in the DPF 50 as an example of a detection unit. The DPF temperature sensor 26 of the embodiment is mounted through the casing 51 and the filter case 52, and the tip thereof is located between the diesel oxidation catalyst 53 and the soot filter 54.

  Further, the DPF 50 is provided with a differential pressure sensor 68 that detects a clogged state of the soot filter 54 as an example of a detection unit. The differential pressure sensor 68 of the embodiment detects a pressure difference (differential pressure) between the upstream and downstream sides of the soot filter 54 in the DPF 50. In this case, the upstream side exhaust pressure sensor 68 a constituting the differential pressure sensor 68 is attached to the lid 67 of the exhaust gas introduction pipe 65, and the downstream side exhaust pressure sensor 68 b is interposed between the soot filter 54 and the resonance chamber 63. It is installed. It is well known that there is a certain law between the pressure difference between the upstream and downstream of the DPF 50 and the amount of PM accumulated in the DPF 50. In the embodiment, the PM accumulation amount in the DPF 50 is estimated from the pressure difference detected by the differential pressure sensor 68, and the intake throttle device 81 and the common rail 120 are operated based on the estimation result, thereby regenerating the soot filter 54. Control (DPF regeneration control) is executed.

  The clogged state of the soot filter 54 is not limited to the differential pressure sensor 68 but may be an exhaust pressure sensor that detects the pressure upstream of the soot filter 54 in the DPF 50. When the exhaust pressure sensor is adopted, the pressure (reference pressure) on the upstream side of the soot filter 54 when PM is not deposited on the soot filter 54 is compared with the current pressure detected by the exhaust pressure sensor. As a result, the clogged state of the soot filter 54 is determined.

  In the above configuration, the exhaust gas from the engine 5 enters the exhaust gas introduction pipe 65 via the exhaust introduction port 55 and is ejected into the filter case 52 from each communication hole 66 formed in the exhaust gas introduction pipe 65. After being dispersed over a wide area in the filter case 52, the diesel oxidation catalyst 53 and the soot filter 54 are passed through in this order for purification. At this stage, PM in the exhaust gas is collected without passing through the porous partition wall between the cells in the soot filter 54. Thereafter, exhaust gas that has passed through the diesel oxidation catalyst 53 and the soot filter 54 is discharged from the exhaust outlet 61.

When exhaust gas passes through the diesel oxidation catalyst 53 and the soot filter 54, if the exhaust gas temperature exceeds the regeneration boundary temperature (for example, about 300 ° C.), the action of the diesel oxidation catalyst 53 causes NO in the exhaust gas. (Nitric oxide) is oxidized to unstable NO ₂ (nitrogen dioxide). Then, the PM trapping ability of the soot filter 54 is recovered (DPF 50 is regenerated) by oxidizing and removing the PM deposited on the soot filter 54 with O (oxygen) released when NO ₂ returns to NO. become.

(3). Configuration Related to Engine Control Next, a configuration related to control of the engine 70 will be described with reference to FIGS. 3, 5, and 6. As shown in FIG. 1, an ECU 11 is provided for operating a fuel injection valve 119 for each cylinder in the engine 70. The ECU 11 includes a CPU 31 that executes various arithmetic processes and controls, a ROM 32 that stores various data fixedly in advance, an EEPROM 33 that stores control programs and various data in a rewritable manner, and temporarily stores control programs and various data. RAM 34, a timer 35 for time measurement, an input / output interface, and the like, which are arranged in the engine 70 or in the vicinity thereof.

  On the input side of the ECU 11, at least the rail pressure sensor 12 that detects the fuel pressure in the common rail 120, the electromagnetic clutch 13 that rotates or stops the fuel pump 116, and the rotational speed (camshaft position of the crankshaft) of the engine 70 are detected. An engine speed sensor 14, an injection setter 15 for detecting and setting the number of fuel injections of the injector 115 (the number of fuel injections during one stroke), a throttle position sensor 16 for detecting the operating position of an accelerator operating tool (not shown), An intake air temperature sensor 17 for detecting the intake air temperature in the intake passage, an exhaust gas temperature sensor 18 for detecting the exhaust gas temperature in the exhaust passage, a coolant temperature sensor 19 for detecting the coolant temperature of the engine 70, and the fuel temperature in the common rail 120 The fuel temperature sensor 20 for detecting the pressure difference, the differential pressure sensor 68 (upstream exhaust pressure sensor 68a The downstream exhaust pressure sensor 68b), the DPF temperature sensor 26 for detecting the exhaust gas temperature in the DPF 50, an automatic auxiliary regeneration mode described later, or a reset regeneration mode (also referred to as a forced regeneration mode). A mode selection switch 45 as a mode selection input means for selecting the above, a lift lever position sensor 46 for detecting a rotation operation angle (operation amount) of the fork lift lever 235, and a rotation operation angle (operation amount) of the tilt lever 236. Is connected to a tilt lever position sensor 47 and the like.

  At the output side of the ECU 11, electromagnetic solenoids of the fuel injection valves 119 for at least four cylinders are respectively connected. That is, the high-pressure fuel stored in the common rail 120 is injected from the fuel injection valve 119 in a plurality of times during one stroke while controlling the fuel injection pressure, the injection timing, the injection period, and the like, so that nitrogen oxide (NOx ), And complete combustion with reduced generation of PM, carbon dioxide, and the like is performed to improve fuel efficiency.

  Further, on the output side of the ECU 11, an intake throttle device 81 for adjusting the intake pressure (intake amount) of the engine 70, an exhaust throttle device 82 for adjusting the exhaust pressure of the engine 70, and a failure notification of the ECU 11 are notified. ECU failure lamp 22, exhaust gas temperature warning lamp 23 for notifying abnormal temperature (abnormally low temperature or abnormally high temperature) of exhaust gas temperature in DPF 50, regeneration lamp 24 that is turned on in accordance with DPF 50 regeneration operation, and DPF 50 regeneration operation being prohibited A regeneration prohibition lamp 28 is connected as a regeneration prohibition notification means that operates. Data relating to blinking of each of the lamps 22 to 24 and 28 is stored in the EEPROM 33 of the ECU 11 in advance. As will be described in detail later, the regeneration lamp 24 functions as a regeneration notice unit that operates before the execution of the automatic auxiliary regeneration mode, a role as a forced regeneration notice unit that operates before the execution of the reset regeneration mode, and the DPF 50 A single display that also serves as a playback notification means for notifying that the playback operation is in progress is configured. As shown in FIG. 7, the mode selection switch 45 and the lamps 22 to 24 and 28 are provided on the instrument panel 40 in the working machine to be mounted with the engine 70.

  The mode selection switch 45 is a rocker (seesaw) type switch. When one end side (left side in FIG. 7) is pressed, the automatic auxiliary regeneration mode is executed according to the clogged state of the DPF 50, and the other end side (see FIG. 7 is configured to execute a reset regeneration mode in accordance with the clogged state of the DPF 50. As will be described in detail later, while the operator operates the fork lift lever 235 or the tilt lever 236, the current driving state of the engine 70 is maintained and execution of the automatic auxiliary regeneration mode and the reset regeneration mode is prohibited. Is configured to do. That is, while the operator operates the fork lift lever 235 or the tilt lever 236, the engine 70 is not forcedly driven and post-injected so that the exhaust gas temperature rises.

  In the EEPROM 33 of the ECU 11, an output characteristic map M (see FIG. 6) indicating the relationship between the rotational speed N of the engine 70 and the torque T (load) is stored in advance. The output characteristic map M is obtained by experiments or the like. In the output characteristic map M shown in FIG. 6, the rotational speed N is taken on the horizontal axis and the torque T is taken on the vertical axis. The output characteristic map M is a region surrounded by a solid line Tmx drawn upwardly. A solid line Tmx is a maximum torque line representing the maximum torque for each rotational speed N. In this case, if the model of the engine 70 is the same, the output characteristic maps M stored in the ECU 11 are all the same (common). As shown in FIG. 6, the output characteristic map M is divided vertically by a boundary line BL representing the relationship between the rotational speed N and the torque T when the exhaust gas temperature is the regeneration boundary temperature (about 300 ° C.). . The upper region across the boundary line BL is a reproducible region in which PM deposited on the soot filter 54 can be oxidized and removed (the oxidizing action of the oxidation catalyst 53 works), and the lower region is not oxidized and removed of PM. This is a non-reproducible region that accumulates on the soot filter 54.

  The ECU 11 basically calculates the torque T based on the output characteristic map M, the rotational speed N detected by the engine speed sensor 14, and the throttle position detected by the throttle position sensor 16 and performs target fuel injection. The fuel injection control for obtaining the amount and operating the common rail system 117 based on the calculation result is executed. Here, the fuel injection amount is adjusted by adjusting the valve opening period of each fuel injection valve 119 and changing the injection period to each injector 115.

(4). Next, an example of DPF 50 regeneration control by the ECU 11 will be described with reference to the flowcharts of FIGS. By the way, as the control mode of the engine 70 in the embodiment (control format related to DPF 50 regeneration), at least the normal operation mode for running on the road and various operations, and the exhaust gas temperature automatically when the clogged state of the DPF 50 exceeds a specified level An automatic auxiliary regeneration mode for raising, a reset regeneration mode for supplying fuel into the DPF 50 by post-injection E (which may be referred to as a forced regeneration mode), and setting the engine 70 to a minimum necessary driving state (in the working machine) There is a limp home mode that ensures the minimum required driving function.

  In the automatic auxiliary regeneration mode, the intake amount and the exhaust amount are limited by closing at least one of the intake throttle device 81 and the exhaust throttle device 82 to a predetermined opening based on the detection information of the differential pressure sensor 68. Then, since the engine 70 load increases, the engine 70 output is increased by the increase of the engine load in conjunction with this, and the exhaust gas temperature from the engine 70 is raised. As a result, PM in the DPF 50 (soot filter 54) can be burned and removed.

  In the reset regeneration mode (forced regeneration mode), when the automatic auxiliary regeneration mode is executed, the clogged state of the DPF 50 is not improved (PM remains), or the accumulated drive time Te of the engine 70 is set to a set time T0 (for example, about 100 hours). It is executed when the degree is exceeded. In the reset regeneration mode, fuel is supplied into the DPF 50 by the post-injection E, and the fuel is combusted by the diesel oxidation catalyst 53, thereby raising the exhaust gas temperature in the DPF 50 (about 560 ° C.). As a result, the PM in the DPF 50 (soot filter 54) can be forcibly burned and removed.

  The limp home mode is executed when the clogged state of the DPF 50 is not improved even when the reset regeneration mode is executed, and the PM is over-deposited (a state in which the PM is likely to runaway). . In the limp home mode, the upper limit of the engine 70 output (the rotational speed N and the torque T) and the driveable time of the engine 70 are limited, so that the engine 70 is maintained in the minimum necessary driving state. As a result, the work machine (forklift car 220) can be removed from the work place or moved to a store / service center, for example. That is, the minimum necessary traveling function can be secured in the work machine (forklift car 220).

  As can be understood from the description regarding the above modes, for example, the engine 70, the intake throttle device 81, the exhaust throttle device 82, the common rail system 117, and the like are members involved in the DPF 50 regeneration operation. These 70, 81, 82, and 117 constitute a regeneration device for burning and removing PM in the DPF 50.

  As shown in FIG. 8, each of the above modes is executed based on a command from the ECU 11. That is, the algorithm shown in the flowchart of FIG. 8 is stored in the EEPROM 33. Each mode described above is executed by calling the algorithm to the RAM 34 and then processing the CPU 31.

  As shown in the flowchart of FIG. 8, in the DPF 50 regeneration control, first, it is determined whether or not the cumulative drive time Te of the engine 70 is equal to or longer than the set time T0 (S01). At this stage, the normal operation mode is executed. The set time T0 of the embodiment is set to about 100 hours, for example. The accumulated driving time Te of the engine 70 is measured using the time information of the timer 35 in the ECU 11 while the engine 70 is being driven, and is stored and accumulated in the EEPROM 33.

  If the cumulative drive time Te is equal to or longer than the set time T0 (S01: YES), the process proceeds to step S12 described later. If the cumulative drive time Te is less than the set time T0 (S01: NO), then, the PM accumulation amount in the DPF 50 is estimated based on the detection result from the differential pressure sensor 68, and the estimation result is a specified amount (specified level). It is determined whether or not this is the case (S02). When it is determined that the PM accumulation amount is less than the prescribed amount (S02: NO), the process returns to step S01 and the normal operation mode is continued. The prescribed amount in the embodiment is set to 8 g / l, for example. When it is determined that the PM accumulation amount is equal to or greater than the specified amount (S02: NO), it is determined which mode is selected by the mode selection switch 45 (S03). When the selected mode is the reset playback mode, the process proceeds to step S12 described later. If the selected mode is the automatic auxiliary regeneration mode, the regeneration lamp 24 is blinked at a low speed (S04) to notify the operator of the DPF 50 regeneration operation (automatic auxiliary regeneration mode). In this case, the blinking frequency of the regeneration lamp 24 is set to 1 Hz, for example.

  Next, it is determined whether or not at least one of the fork raising / lowering lever 235 and the tilting lever 236 is being operated (S05). If it is being operated (S05: YES), the regeneration prohibiting lamp 28 is turned on (S05). Return to S04. For this reason, in the steps S04 to S06, the control mode of the engine 70 remains in the normal operation mode even though the PM accumulation amount is not less than the specified amount, and the current driving state of the engine 70 is maintained. become. That is, the transition to the automatic auxiliary regeneration mode (which may be referred to as the DPF 50 regeneration operation or the operation of the regeneration device) is prohibited. Further, while operating at least one of the levers 235 and 236, the regeneration prohibiting lamp 28 is lit to appeal to the operator's vision that the DPF 50 regeneration operation (automatic auxiliary regeneration mode) is prohibited. This ensures the operator's attention.

  In step S05, if both levers 235 and 236 are not being operated (S05: NO), it is determined whether or not a predetermined time has passed in a state where both levers 235 and 236 have not been operated (S07). If the predetermined time has not elapsed (S07: NO), the process directly returns to step S04. When the predetermined time has elapsed (S07: YES), the regeneration prohibiting lamp 28 is turned off, while the regeneration lamp 24 that has been blinking at a low speed is turned on (S08), and then the automatic auxiliary regeneration mode is executed (S09).

  In the automatic auxiliary regeneration mode, as described above, the load on the engine 70 is increased by restricting the intake air amount and the exhaust air amount using at least one of the intake air throttle device 81 and the exhaust air throttle device 82, and accordingly, the engine 70 output is increased. Increase the exhaust gas temperature. As a result, the PM in the DPF 50 is burned and removed, and the PM collection capability of the DPF 50 is restored. The automatic auxiliary regeneration mode of the embodiment is executed, for example, for about 20 minutes, and after the elapse of the time, the opening degree of the intake throttle device 81 and the exhaust throttle device 82 returns to the original state before narrowing.

  After the execution of the automatic auxiliary regeneration mode, the PM accumulation amount in the DPF 50 is estimated again based on the detection result from the differential pressure sensor 68, and it is determined whether or not the estimation result is less than the allowable amount (S10). When it is determined that the PM accumulation amount is equal to or less than the allowable amount (S10: YES), the regeneration lamp 24 is turned off to notify the end of the automatic auxiliary regeneration mode (S11), and the routine returns to step S01 to execute the normal operation mode. The allowable amount of the embodiment is set to 4 g / l, for example. When it is determined that the PM accumulation amount exceeds the allowable amount (S10: NO), PM in the DPF 50 is not sufficiently removed despite the execution of the automatic auxiliary regeneration mode (the clogging state does not improve). ) State, the regeneration lamp 24 blinks at high speed (S12), and the operator is notified of the execution of the DPF 50 regeneration operation (reset regeneration mode). In this case, the blinking frequency of the regeneration lamp 24 is set to a frequency different from that in the automatic auxiliary regeneration mode. For example, the blinking frequency of the regeneration lamp 24 for reset regeneration mode notification is set to 2 Hz.

  Next, it is determined whether or not at least one of the fork lift lever 235 and the tilt lever 236 is being operated (S13). If it is being operated (S04: YES), the regeneration prohibiting lamp 28 is turned on (S14), and then the step is performed. Return to S12. Therefore, in the steps S12 to S14, the current driving state of the engine 70 is maintained and the shift to the reset regeneration mode is prohibited although the clogged state of the DPF 50 is not improved. Also in this case, while operating at least one of the levers 235 and 236, the regeneration prohibition lamp 28 is lit to appeal to the operator's vision that the DPF 50 regeneration operation (reset regeneration mode) is prohibited. The operator's attention is surely raised.

  In step S13, if both levers 235 and 236 are not being operated (S13: NO), it is determined whether or not a predetermined time has passed in a state where both levers 235 and 236 have not been operated (S15). If the predetermined time has not elapsed (S15: NO), the process directly returns to step S12. When the predetermined time has elapsed (S15: YES), the regeneration prohibiting lamp 28 is turned off, while the regeneration lamp 24 that has been flashing at high speed is turned on (S16), and the reset regeneration mode is executed (S17).

  In the reset regeneration mode, as described above, fuel is supplied into the DPF 50 by the post-injection E of the common rail system 117, and the fuel is combusted by the diesel oxidation catalyst 53, whereby the exhaust gas temperature in the DPF 50 is raised. As a result, the PM in the DPF 50 is forcibly burned and removed, and the PM collection capability of the DPF 50 is restored. The reset regeneration mode of the embodiment is executed for about 30 minutes, for example, and the common rail system 117 does not perform the post injection E after the lapse of the time. When the reset regeneration mode is executed, the cumulative driving time Te of the engine 70 is once reset and newly measured using the time information of the timer 35.

  After execution of the reset regeneration mode, the PM accumulation amount in the DPF 50 is estimated based on the detection result from the differential pressure sensor 68, and it is determined whether or not the estimation result is equal to or less than an allowable amount (S18). When it is determined that the PM accumulation amount is equal to or less than the allowable amount (S18: YES), the regeneration lamp 24 is turned off to notify the end of the reset regeneration mode (S11), and the routine returns to step S01 to execute the normal operation mode. If it is determined that the PM accumulation amount exceeds the allowable amount (S18: NO), it is considered that the PM is in an over-deposition state where the clogged state of the DPF 50 is not improved even though the reset regeneration mode is executed. . In this case, since there is concern about the possibility of PM runaway combustion, the limp home mode is executed (S19). In the limp home mode, as described above, the upper limit value of the output of the engine 70 (rotational speed N and torque T) and the drivable time of the engine 70 are limited to keep the engine 70 in the minimum necessary driving state. As a result, the minimum necessary traveling function can be ensured in the work machine (forklift car 220).

  Now, the ECU 11 of the embodiment is configured to execute the interrupt process shown in FIG. 9 during the execution of the DPF 50 regeneration control. The interruption process is to check the detection result of the DPF temperature sensor 26 at appropriate time intervals. In this case, as shown in the flowchart of FIG. 9, it is determined whether or not a predetermined time has elapsed when the exhaust gas temperature TP in the DPF 50 is equal to or lower than the specified temperature TP0 (S21). If so (S21: YES), the exhaust temperature warning lamp 23 blinks (S22), and the operator is notified of the execution of the DPF 50 regeneration operation (automatic auxiliary regeneration mode). The specified temperature TP0 is lower than the regeneration boundary temperature (for example, about 300 ° C.). That is, as the specified temperature TP0, a non-renewable temperature at which PM is deposited on the soot filter 54 without being oxidized and removed is employed. The specified temperature TP0 of the embodiment is set to about 250 ° C., for example. The blinking frequency of the exhaust temperature warning lamp 23 is set to 1 Hz, for example.

  Next, it is determined whether or not at least one of the fork lift lever 235 and the tilt lever 236 is being operated (S23). If it is being operated (S23: YES), the regeneration prohibiting lamp 28 is turned on (S24), and then the step Return to S22. If both levers 235 and 236 are not being operated (S23: NO), it is determined whether or not a predetermined time has passed in a state where both levers 235 and 236 have not been operated (S25). If the predetermined time has not elapsed (S25: NO), the process directly returns to step S22. When the predetermined time has elapsed (S25: YES), the regeneration prohibiting lamp 28 is turned off (S26), the automatic auxiliary regeneration mode is executed (S27), and then the process returns.

  The automatic auxiliary regeneration mode in this case has a shorter execution time than the automatic auxiliary regeneration mode of step S09 because PM does not necessarily accumulate in the DPF 50. In the embodiment, the execution time of the automatic auxiliary reproduction mode of step S09 is about 20 minutes, for example, while the execution time of the automatic auxiliary reproduction mode of step S27 is about ¼, for example, about 5 minutes. After the elapse of the time, the opening degree of the intake throttle device 81 and the exhaust throttle device 82 returns to the original state before narrowing them.

(5). Summary As is apparent from the above description and FIGS. 3, 7 and 8, the common rail 120 type engine 70 mounted on the work machine 220, and the exhaust gas purification device 50 disposed in the exhaust system 77 of the engine 70, , And at least one of an intake throttle device 81 and an exhaust throttle device 82 disposed in the intake and exhaust systems 76 and 77 of the engine 70, and operating the at least one throttle device 81, 82 to operate the engine The auxiliary regeneration mode in which the exhaust gas temperature from 70 is raised and the forced regeneration mode in which fuel is supplied into the exhaust gas purification device 50 by post injection E can be executed, and the exhaust gas purification device 50 Select whether to execute the auxiliary regeneration mode or the forced regeneration mode when the clogged state of the battery exceeds a specified level Mode selection input means 45 is provided, so that by operating the mode selection input means 45, the operator can select the control mode of the engine 70 (control format relating to regeneration of the exhaust gas purifying device 50) according to the working state. become. For this reason, it is possible to suppress the loss of work time due to the time required for regeneration of the exhaust gas purification device 50 by the expansion devices 81 and 82, and the effect of improving work efficiency can be achieved.

  As apparent from the above description and FIGS. 3 and 8, if the clogged state of the exhaust gas purification device 50 is not improved even after the auxiliary regeneration mode is executed, the mode selection input means 45 is involved in the selected state. Since the forced regeneration mode is executed, the operator does not need to re-operate the mode selection input means 45 to reselect the forced regeneration mode. It is possible to smoothly shift from the auxiliary regeneration mode to the forced regeneration mode in which particulate matter can be forcibly and efficiently burned and removed. Therefore, the particulate matter in the exhaust gas purifying device 50 is surely burned and removed in accordance with the situation where the clogged state of the exhaust gas purifying device 50 is not improved while saving the trouble of operating the mode selection input means 45. In other words, the exhaust gas purifying device 50 and the engine 70 can be prevented from malfunctioning due to the clogging of the particulate matter.

  As is apparent from the above description and FIGS. 3, 7, and 8, the exhaust gas purifying device 50 is in a clogged state because it includes the forced regeneration notice means 24 that operates before the forced regeneration mode is executed. In switching to the forced regeneration mode without improvement, the operator can grasp in advance the fact of shifting to the forced regeneration mode by the operation of the forced regeneration notice means 24, and the impact of the output fluctuation and the change in engine sound that occur thereafter. Can be assumed in advance. Therefore, there is an effect that the operator feels uncomfortable due to the regeneration operation of the exhaust gas purification device 50.

  As apparent from the above description and FIGS. 2, 3, and 8, the engine 70 mounted on the work machine 220, the exhaust gas purification device 50 disposed in the exhaust system 77 of the engine 70, and the exhaust gas Regenerators 70, 81, 82, and 117 for burning and removing particulate matter in the purification device 50, and during operation of the operating means 235 and 236 for the working unit 227 provided in the working machine 220. Since the regenerators 70, 81, 82, 117 are not operated regardless of the clogged state of the exhaust gas purifying device 50, the operation means 235, 236 for the working unit 227 is operated. Thus, the regeneration operation of the exhaust gas purification device 50 can be prohibited. That is, the regeneration operation of the exhaust gas purifying device 50 can be prohibited by the operator's intention according to the working state of the working machine 220 or the like. For this reason, while the regeneration control for recovering the particulate matter collecting ability of the exhaust gas purifying device 50 can be executed, it is possible to smoothly perform the precise work that the operator performs by relying on the engine sound. That is, it is possible to eliminate the drawbacks of the regeneration operation of the exhaust gas purifying device 50 that may hinder the precise operation.

  As is clear from the above description and FIGS. 3, 7 and 8, the regenerators 70, 81, 82 and 117 are not operated under the condition that the clogged state of the exhaust gas purifying device 50 is not less than a specified level. Therefore, while the operation means 235 and 236 for the working unit 227 is being operated, the exhaust gas purification device 50 is notified by the regeneration prohibition notification means 28. The fact that the reproduction operation is prohibited can be appealed to the operator's sight, and the operator's attention can be surely attracted. By confirming the state of the reproduction prohibition notification means 28, it can be easily confirmed whether or not reproduction is prohibited.

  As is clear from the above description and FIGS. 3 and 8, the exhaust gas purifying device 50 is in a non-operated state after the operation of the operating means 235 and 236 under the condition that the clogged state of the exhaust gas purifying device 50 is not less than a specified level. Since the prohibition of the operation of the regenerators 70, 81, 82, 117 is canceled when a predetermined time has elapsed, the exhaust gas purification is performed as soon as the operation of the operation means 235, 236 is finished. The device 50 regeneration operation is not executed (the exhaust gas purification device 50 regeneration operation is executed after a certain grace period). For this reason, there is an effect that it is possible to smoothly shift to the regeneration operation of the exhaust gas purifying device 50 while reducing the uncomfortable feeling to the operator as much as possible.

  As apparent from the above description and FIGS. 3 and 9, the engine 70 mounted on the work machine 220, the exhaust gas purification device 50 disposed in the exhaust system 77 of the engine 70, and the intake and exhaust of the engine 70 And at least one of an intake throttle device 81 and an exhaust throttle device 82 arranged in the systems 76 and 77, and the exhaust gas temperature from the engine 70 is controlled by operating the at least one throttle device 81 or 82. When the exhaust gas temperature in the exhaust gas purification device 50 is equal to or lower than a preset specified temperature TP0, the auxiliary regeneration mode to be raised can be executed, regardless of the clogged state of the exhaust gas purification device 50. Since the auxiliary regeneration mode is executed, the exhaust gas purification device 50 is disposed away from the engine 70. As described above, even in a situation where the exhaust gas temperature tends to decrease, the exhaust gas temperature can be positively increased, and the accumulation of particulate matter in the exhaust gas purification device 50 is reduced and delayed. be able to. Even when the exhaust gas purification device 50 is arranged away from the engine 70, the purification function and the regeneration function of the exhaust gas purification device 50 can be maintained over a long period of time.

  As is apparent from the above description and FIGS. 3, 8, and 9, when the auxiliary regeneration mode is executed based on the exhaust gas temperature in the exhaust gas purification device 50, the normal operation mode is reached after a predetermined time has elapsed. Therefore, it is not necessary for the operator to perform, for example, a return operation for returning to the normal operation mode. Therefore, there is an effect that it is possible to reduce the operation burden on the operator by omitting the trouble of operation.

  As apparent from the above description and FIGS. 3 and 9, the execution time of the auxiliary regeneration mode based on the exhaust gas temperature in the exhaust gas purification device 50 is the auxiliary time based on the clogged state of the exhaust gas purification device 50. Since it is set to be shorter than the execution time of the regeneration mode, it is possible to suppress the loss of work time due to the exhaust gas temperature increase using the expansion devices 81 and 82 as much as possible. As a result, there is an effect of helping to improve work efficiency.

(6). Another Example when Engine is Mounted on Backhoe FIGS. 10 to 13 show another example when the engine 70 is mounted on a backhoe 141 as a work machine. In FIG. 11, the cabin 146 is not shown for convenience of explanation. The backhoe 141 includes a crawler type traveling device 142 having a pair of left and right traveling crawlers 143 (shown only on the left side in FIG. 10), and a swivel base 144 (airframe) provided on the traveling device 142. The swivel 144 is configured to be capable of horizontal swivel over all 360 ° directions with a swivel motor (not shown). An earth discharging plate 145 is attached to the front portion of the traveling device 142 so as to be rotatable up and down.

  On the swivel base 144, a cabin 146 as a control unit and a diesel four-cylinder type engine 70 are mounted. A working unit 150 having a boom 151, an arm 152, and a bucket 153 for excavation work is provided at the front of the swivel base 144. As shown in detail in FIG. 11, inside the cabin 146 is a control seat 148 on which an operator is seated, a throttle lever 166 as a throttle operation means for setting and maintaining the output rotational speed of the engine 70, and an operation means for the working unit 150. Lever / switch groups 167 to 170 (a turning operation lever 167, an arm operation lever 168, a bucket operation switch 169, and a boom operation lever 170) are arranged.

  The boom 151 which is a constituent element of the working unit 150 is formed in a shape that protrudes forward at the front end side and is bent in a letter shape in a side view. A base end portion of the boom 151 is pivotally attached to a boom bracket 154 attached to the front portion of the swivel base 144 so as to be swingable about a horizontal boom shaft 155. On the inner surface (front surface) side of the boom 151, a one-rod double-acting boom cylinder 156 for swinging it up and down is disposed. The cylinder side end of the boom cylinder 156 is pivotally supported by the front end of the boom bracket 154 so as to be rotatable. The rod side end of the boom cylinder 156 is pivotally supported by a front bracket 157 fixed to the front surface side (dent side) of the bent portion of the boom 151.

  A base end portion of a long-angle cylindrical arm 152 is pivotally attached to a distal end portion of the boom 151 so as to be swingable about a lateral arm shaft 159. A single-rod double-acting arm cylinder 160 for swinging and swinging the arm 152 is arranged on the front upper surface side of the boom 151. The cylinder side end of the arm cylinder 160 is pivotally supported by a rear bracket 158 that is fixed to the back side (protrusion side) of the bent portion of the boom 151. The rod side end portion of the arm cylinder 160 is pivotally supported by an arm bracket 161 fixed to the outer surface (front surface) of the base end side of the arm 152.

  A bucket 153 as an excavation attachment is pivotally attached to the distal end portion of the arm 152 so as to be swiveled around a lateral bucket shaft 162. On the outer surface (front surface) side of the arm 152, a one-rod double-acting bucket cylinder 163 for scooping and rotating the bucket 153 is disposed. The cylinder side end of the bucket cylinder 163 is pivotally supported by the arm bracket 161 so as to be rotatable. The rod side end of the bucket cylinder 163 is pivotally supported by the bucket 153 via a connection link 164 and a relay rod 165.

  The aspect of DPF regeneration control in another example is basically the same as that of the forklift car 220 described above. In this case, in steps S05 and S13 in FIG. 12 and in step S23 in FIG. 13, lever / switch groups 167 to 170 (the turning operation lever 167, the arm operation lever 168, the bucket operation switch are used as the operation means for the working unit 150. 169 and the boom operation lever 170) are different from the forklift car 220 described above in that it is determined whether or not at least one of the lever / switch groups 167 to 170 is being operated. As described above, although the operation means 167 to 170 to be discriminated are different, the regenerators 70, 81, and 82 are operated during operation of the operation means 167 to 170 with respect to the working unit 150 regardless of the clogged state of the exhaust gas purification device 50. , 117 is the same as that of the forklift car 220 described above. Even when such control is adopted, the same effects as those of the forklift car 220 described above can be obtained.

(7). Others The present invention is not limited to the above-described embodiment, and can be embodied in various forms. The configuration of each part is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

11 ECU
23 exhaust temperature warning lamp 24 regeneration lamp (forced regeneration notice means)
26 DPF temperature sensor 28 Regeneration prohibition lamp (regeneration prohibition notification means)
45 Mode selection switch (Mode selection input means)
50 DPF (Exhaust Gas Purifier)
70 Engine 81 Intake throttle device 82 Exhaust throttle device 117 Common rail system 120 Common rail

Claims (3)

An engine mounted on a work machine, an exhaust gas purification device disposed in an exhaust system of the engine, and a regeneration device for burning and removing particulate matter in the exhaust gas purification device. During the operation of the operating means for the working unit provided in the machine, the regeneration device is configured not to operate regardless of the clogged state of the exhaust gas purification device.
Exhaust gas purification system for work equipment. Regeneration prohibition notifying means that operates when the regeneration device is not operated under the condition that the clogged state of the exhaust gas purification device is not less than a specified level,
The exhaust gas purification system for a working machine according to claim 1. The configuration is such that the prohibition of operation of the regenerator is canceled when a predetermined time has elapsed after the operation of the operation means is completed after the operation means has been operated under a condition where the clogged state of the exhaust gas purification device is equal to or higher than a specified level. Being
An exhaust gas purification system for a working machine according to claim 1 or 2.

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