JP2013113290A - Working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an increase in accumulation amount of particulate matter (PM accumulation amount) deposited on a DPF when an operator is not aboard a working machine (the operator has gotten off the working machine).SOLUTION: A working machine includes: an exhaust emission control device 31 provided with a filter 41 for collecting particulate matter contained in exhaust emission gas discharged from a diesel engine 9; a filter regeneration means 50 that removes particulate matter deposited on the filter 41 of the exhaust emission control device 31 by combusting the particulate matter; a getting-on/off confirmation means 53 for confirming getting-on or getting-off; and an engine rotation control means 32 that automatically lowers the rotational frequency of an engine 9 when the engine 9 is operated in a state that the getting-off is confirmed by the getting-on/off confirmation means 53 and the accumulation amount of particulate matter deposited on the filter 41 exceeds a predetermined value.

Description

  The present invention relates to a work machine such as a backhoe, a wheel loader, and a tractor provided with a diesel particulate filter (DPF).

In order to improve and solve environmental problems in recent years, exhaust gas regulations for diesel engines and the like have been strengthened. In working machines such as construction machines and agricultural machines, various techniques for reducing particulate matter (particulates) contained in exhaust gas have been developed in order to cope with such exhaust gas regulations.
In general, diesel engines are provided with an exhaust gas purification device that collects particulate matter contained in the exhaust gas. The exhaust gas purification device collects particulate matter by passing the exhaust gas through a diesel particulate filter (DPF) provided therein. Since the collected particulate matter gradually accumulates in the DPF of the exhaust gas purification device, the particulate matter is appropriately removed to prevent the DPF from becoming clogged and increasing the air resistance of the exhaust system. I have to play it.

As techniques relating to such DPF regeneration, there are techniques shown in Patent Document 1 and Patent Document 2.
Japanese Patent Application Laid-Open No. 2005-228561 is a technology for automatically stopping an engine when regeneration is completed by performing throttle of an intake throttle (throttle of an intake / exhaust valve) or post injection in a DPF regeneration process in a common rail type diesel engine.

  Patent Document 2 is a technique for determining the clogging of the DPF based on the operating state of the engine during the operation of the construction machine and regenerating the DPF without stopping the engine when the DPF is clogged.

JP 2010-127253 A JP 2010-270611 A

  Patent Document 1 and Patent Document 2 also operate the engine to regenerate the DPF, but these techniques reduce the amount of DPF accumulated (PM accumulated) in the DPF regeneration processing (regeneration operation). This is a technology that focuses only on this. In other words, in these technologies, although the process of reducing the PM deposition amount once increased by the regeneration operation of the DPF is actively performed, it is originally considered that the processing is performed so that the PM deposition amount does not increase. The situation is not being done.

  Accordingly, the present invention provides a working machine capable of suppressing an increase in the amount of particulate matter deposited (PM deposition amount) deposited on the DPF even when the operator is not in the vehicle (alighting state). The purpose is to provide.

In order to achieve the above object, the present invention has taken the following measures.
That is, the technical means for solving the problems in the present invention is an exhaust gas equipped with a filter that collects particulate matter contained in exhaust gas discharged from a diesel engine according to the working machine according to claim 1. A purification device; filter regeneration means for burning and removing particulate matter deposited on the filter of the exhaust gas purification device; and boarding / alighting confirmation means for confirming whether to get on or off the vehicle. Engine rotation control means for automatically reducing the engine speed when the engine operates in a state where the accumulated amount of particulate matter deposited on the filter is equal to or greater than a predetermined value. It is characterized by.

According to the work machine of the second aspect, the engine rotation control means reduces the engine rotation speed to zero when the engine rotation speed in the dismounting state is the idling rotation speed and the accumulation amount is a predetermined value or more. It is characterized by.
According to the work machine of the third aspect, the engine rotation control means sets the engine rotation speed to idling rotation when the engine rotation speed when getting off is equal to or higher than the idling rotation speed and the accumulation amount is equal to or greater than a predetermined value. It is characterized by being gradually lowered to a number to zero.

According to the work machine according to claim 4, when the engine is operated in a state where the boarding is confirmed by the boarding / alighting confirmation unit, and the accumulation amount of the particulate matter deposited on the filter is a predetermined value or more. Comprises an output limiting means for limiting the output of the engine while allowing the engine speed to increase or decrease.
According to a fifth aspect of the present invention, when the engine speed is lowered by the engine speed control means, the work machine is provided with notifying means for notifying that the engine speed is to be lowered.

According to the first aspect, for example, it is possible to suppress an increase in the amount of accumulated PM when the worker leaves the engine for a long time with the engine running for a break or temporarily interrupting the work.
According to the second and third aspects, an increase in the amount of accumulated PM due to idling rotation can be reliably suppressed.

According to the fourth aspect, in the state where the operator is on board, an increase in the amount of accumulated PM can be suppressed by limiting the output of the engine.
According to the fifth aspect, for example, it is possible to notify the worker away from the working machine that the PM accumulation amount is increasing.

It is a figure which shows the structure of the exhaust gas purification apparatus in 1st Embodiment. It is a figure which shows transition (change) of PM deposition amount. It is explanatory drawing explaining the fall of the engine speed in 1st Embodiment. It is a figure which shows the structure of the exhaust gas purification apparatus in 2nd Embodiment. It is explanatory drawing explaining the fall of the engine speed in 2nd Embodiment. It is explanatory drawing explaining the fall of the engine speed in 2nd Embodiment. It is the whole backhoe side view.

Embodiments of the present invention will be described below with reference to the drawings.
[First embodiment]
The work machine of the present invention includes a diesel particulate filter (DPF) and a means for burning and removing particulate matter deposited on the DPF. Such work machines include construction machines such as backhoes and compact truck loaders (CTLs), and agricultural machines such as tractors. As described below, backhoes will be described as examples of work machines.

FIG. 7 is a side view showing the overall configuration of the backhoe 1. As shown in FIG. 7, the backhoe 1 includes a lower traveling device 2 and an upper swing body 3.
The traveling device 2 is a crawler traveling device including a pair of left and right traveling bodies 4 each having a rubber cover. The traveling device 2 is provided with a hydraulic motor M that causes the crawler to travel with the power output from the diesel engine 9, and a dozer 5 is provided at the front.

  The swivel body 3 includes a swivel base 7 supported on the traveling device 2 via a swivel bearing 6 so as to be turnable left and right around a swivel axis in the vertical direction, and a working device 8 (excavation) provided at the front of the swivel base 7. Device). On the swivel base 7, a diesel engine 9, a radiator, a driver's seat 10, a fuel tank, a hydraulic oil tank, a control valve for controlling hydraulic oil from the hydraulic oil tank, and the like are provided. Around the driver's seat 10, a display device 11 that displays various information about the backhoe 1 is provided. The driver's seat 10 is surrounded by a cabin 12 provided on the turntable 7.

The work device 8 includes a swing bracket 14 supported by a support bracket 13 provided at the front portion of the swivel base 7 so as to be swingable left and right, and a boom having a base side supported by the swing bracket 14 so as to be swingable up and down. 15. An arm 16 is supported on the front end side of the boom 15 so as to be swingable back and forth, and a bucket 17 is provided on the front end side of the arm 16 so that a squeeze / dump operation can be performed.

  The swing bracket 14 is swung by expansion and contraction of a swing cylinder provided in the swivel base 12. The boom 15 is swung by the expansion and contraction of a boom cylinder 18 interposed between the boom 15 and the swing bracket 14. The arm 16 is swung by the expansion and contraction of an arm cylinder 19 interposed between the arm 16 and the boom 15. The bucket 17 is squeezed and dumped by expansion and contraction of the bucket cylinder 20 interposed between the bucket 17 and the arm 16.

Each of the swing cylinder, the boom cylinder 18, the arm cylinder 19, and the bucket cylinder 20 is configured to expand and contract with hydraulic oil whose flow rate is controlled by a control valve.
FIG. 1 shows the structure of a diesel engine and the exhaust system of the diesel engine. The exhaust system of the diesel engine will be described. Although the diesel engine 9 is often a multi-cylinder engine having a plurality of cylinders (cylinders), FIG. 1 shows and describes the configuration of only one of the cylinders 34.

  As shown in FIG. 1, the diesel engine 9 provides power to various devices (for example, a hydraulic motor M, a hydraulic pump, etc.) mounted on the backhoe 1. An intake port 35 that is an opening for introducing air into the cylinder 34 is formed, and an exhaust port 36 that is an opening for discharging the gas after combustion (combustion gas) from the cylinder 34 is formed. . Further, an intake valve 37 for opening and closing the intake port 34 and an exhaust valve 38 for opening and closing the exhaust port 36 are provided at the upper part of the cylinder 34.

  The intake port 35 is connected to a tubular intake manifold 39 that serves as a flow path for air introduced into the cylinder 34. The exhaust port 36 is connected to a tubular exhaust manifold 30 serving as a flow path for combustion gas discharged from the cylinder 34. A silencer 40 for reducing exhaust noise is provided at the end of the exhaust manifold 30, and the combustion gas passes through the silencer 40 and is discharged into the environment.

  In the exhaust manifold 30, an exhaust gas purification device 31 is provided between the exhaust port 36 and the silencer 40. The exhaust gas purification device 31 collects and purifies particulate matter (PM) contained in the exhaust gas passing therethrough. That is, the combustion gas discharged from the cylinder 34 through the exhaust port 36 becomes exhaust gas, passes through the exhaust manifold 30, is purified by the exhaust gas purification device 31, and reaches the silencer 40.

  This exhaust gas purification device 31 has a diesel particulate filter (DPF) 41 inside. The DPF 41 is a filter for collecting particulate matter (PM) contained in the exhaust gas. For example, the DPF 41 is made of ceramic and has a cross section having a honeycomb structure. In other words, a number of hexagonal column-shaped polygonal through holes are adjacent to each other along the longitudinal direction from one end to the other end of the DPF 41, and each through hole has a predetermined interval along the longitudinal direction of the DPF 41. A porous partition is provided. The DPF 41 having such a honeycomb structure is configured such that the position of the partition wall formed in the through hole in the longitudinal direction of the DPF 41 is different from the position of the partition wall formed in the adjacent through hole.

  The exhaust gas that has entered from one end of the DPF 41 flows toward the other end of the DPF 41 while passing through a porous partition formed in the through hole. Particulate matter contained in the exhaust gas is collected and deposited on the DPF 41 by adhering to the porous partition walls or adhering to the inner walls of the through holes. That is, since the DPF 41 has a structure that causes clogging when the amount of accumulated particulate matter increases, the DPF 41 must be appropriately cleaned so that the amount of particulate matter deposited does not become excessive.

In the present embodiment, this cleaning of the DPF 41 is referred to as “DPF regeneration”, and the operation for that purpose is referred to as “DPF regeneration operation”. In the regeneration of the DPF 41, the particulate matter deposited by burning the DPF 41 to a predetermined temperature or higher is combusted and gasified, and discharged into the environment together with the exhaust gas.
In addition to the DPF 41, the exhaust gas purification device 31 includes an oxidation catalyst for oxidizing the fuel in the particulate matter and the nitrogen oxide in the combustion gas, although not shown.

  An inlet side pressure sensor 42 that detects the exhaust pressure near the inlet of the exhaust gas cleaner 31 is provided on the inlet side of the exhaust gas cleaner 31, and an outlet pressure sensor that detects the exhaust pressure near the outlet on the outlet side. 43 is provided. The entry-side pressure sensor and the exit-side pressure sensor are general pressure sensors composed of, for example, piezoelectric elements. The inlet pressure sensor and the outlet pressure sensor are connected to a differential pressure sensor described below.

  The differential pressure sensor 44 is the difference between the exhaust pressure detected by the inlet pressure sensor and the exhaust pressure detected by the outlet pressure sensor. Is detected. In general, when the particulate matter is not deposited on the DPF 41 and is not clogged, the pressure loss due to the DPF 41 is small. Therefore, the difference between the exhaust pressure detected by the inlet pressure sensor and the outlet pressure sensor is small. The differential pressure detected by the is also a small value. However, when particulate matter accumulates on the DPF 41 and the degree of clogging increases, the pressure loss due to the DPF 41 increases, so the differential pressure detected by the differential pressure sensor also increases. Since the magnitude of the differential pressure corresponds to the degree of clogging of the DPF 41, the magnitude of the differential pressure can be converted into the degree of clogging of the DPF 41, that is, the amount of particulate matter accumulated in the DPF 41.

  As shown in FIG. 1, the exhaust manifold 30 that connects the diesel engine 9 and the exhaust gas purification device 31 detects the temperature (exhaust temperature) of the combustion gas that is exhausted from the diesel engine 9 and travels toward the exhaust gas purification device 31. An exhaust temperature sensor 45 is provided. The exhaust temperature sensor is composed of, for example, a thermistor. The differential pressure detected by the differential pressure sensor as described above and the exhaust temperature detected by the exhaust temperature sensor are sent to the control unit 46, and the control unit 46 performs control for regenerating the DPF. The DPF regeneration control will be described later.

  The control unit 46 controls the entire backhoe 1 in addition to control for regeneration of the DPF. This control part 46 is comprised from several control apparatus (ECU), for example, has engine ECU32 which controls the diesel engine 9, and main ECU33 which controls operation | movement of the backhoe 1 whole. The engine ECU 32 and the main ECU 33 are composed of, for example, a CPU.

  The engine ECU 32 obtains information from sensors installed at various locations of the diesel engine 9 and the power transmission system, calculates the optimal fuel injection amount, injection timing, and ignition timing according to the state of the diesel engine 9 to calculate the diesel engine 9. The control command is issued. As a matter of course, in the diesel engine 9, the engine speed can be increased or decreased by operating an accelerator (accelerator lever) provided around the driver's seat 10.

  Sensors that provide information to the engine ECU 32 include an accelerator opening sensor that detects an accelerator opening (amount of operation of an accelerator lever), a differential pressure sensor 44 that detects a differential pressure of the exhaust gas purification device 31, and an exhaust temperature. Exhaust temperature sensor 45, air flow meter for detecting intake air amount, crank position sensor for detecting engine speed, water temperature sensor for detecting coolant temperature, throttle for detecting valve opening There are position sensors. In addition to these, there are a cam position sensor for detecting the crank position, an oxygen concentration sensor for detecting the oxygen concentration in the intake air, and the like.

The main ECU 33 controls various devices (traveling device, working device, etc.) provided in the backhoe 1 in cooperation with the engine ECU 32. For example, the main ECU 33 performs flow rate control and AI control.
The flow rate control is a control for supplying predetermined hydraulic oil to each cylinder such as the swing cylinder, the boom cylinder 18, the arm cylinder 19 and the bucket cylinder 20, and is an operation member (around the driver's seat 10). The hydraulic oil is controlled based on the operation amount of the operation lever 47. Specifically, in the flow rate control, when the operation lever 47 is swung to one side (left side) from the neutral position and an operation amount on the left side is input, the operated actuator (swing cylinder, boom cylinder 18, arm cylinder 19 and bucket cylinder 20). A current (actuation signal) of a predetermined value is output to the solenoid of the electromagnetic proportional valve corresponding to. Then, the electromagnetic proportional valve opens according to the current value, the pilot pressure of the control valve corresponding to the operated actuator is controlled, and the actuator operates in one direction. When the operation lever 4733 is swung from the neutral position to the opposite side to input the operation amount on the right side, the actuator is operated on the opposite side from the swinging to the left side. Thus, by operating the operation lever 47, the backhoe (working apparatus) 1 operates.

In the AI control, when the operation lever 47 is not operated, the engine speed is set to the idling speed, and when the operation lever 47 is operated, the engine speed corresponds to the accelerator.
Specifically, in the AI control, when an idle switch ON signal is input with the operation lever 47 in the neutral position, an idle signal for setting the engine speed to the idling speed is supplied to the auto idle motor regardless of the operation amount of the accelerator lever. Is output to drive the auto idle motor to set the engine speed to the idling speed. When the operation lever 47 is swung back and forth or left and right and an idle switch OFF signal is input, the engine idle speed is output to the auto idle motor based on the accelerator position signal to drive the auto idle motor. Operate the governor lever and set the engine speed to the speed corresponding to the accelerator lever.

In this manner, the backhoe 1 can be operated by controlling the diesel engine 9 by the engine ECU 32 and controlling various devices such as a work device by the main ECU 33. It should be noted that the control by the engine ECU 32 and the main ECU 33 is not limited to the above.
As described above, the control unit 46 also performs control for regenerating the DPF.

Hereinafter, the regeneration of the DPF will be described in detail.
The control unit 46 is provided with filter regeneration means 50 that regenerates the DPF 41 of the exhaust gas purification device 31. Specifically, the filter regeneration unit 50 is provided in the main ECU 33 that constitutes the control unit 46, and the filter regeneration unit 50 is configured by a program or the like stored in the main ECU 33.

When the amount of particulate matter deposited on the DPF 41 reaches a predetermined amount or more (referred to as PM deposition amount), the filter regeneration means 50 burns and removes the particulate matter deposited on the filter in order to burn off the diesel engine 9 and the exhaust. The gas purification device 31 is controlled to automatically perform processing (regeneration operation) for reducing the amount of deposition.
As shown in FIG. 2, when the PM accumulation amount is equal to or greater than the first threshold value, the filter regeneration unit 50 activates the automatic regeneration mode and starts control of regeneration of the DPF.

  In the automatic regeneration mode, the filter regeneration means 50 outputs a signal for narrowing the intake throttle of the diesel engine 9 to the engine ECU 32, and raises the exhaust temperature by narrowing the intake throttle under the control of the engine ECU 32. That is, in the automatic regeneration mode, “intake throttle throttling” is performed in which particulate matter is combusted by an increase in exhaust gas temperature due to throttling of the intake throttle. Further, in the automatic regeneration mode, the filter regeneration means 50 outputs a signal for injecting fuel to the burned gas to the engine ECU 32, and the exhaust temperature is increased by injecting fuel under the control of the engine ECU 32. That is, in the automatic regeneration mode, “post-injection” is performed in which particulate matter is combusted by an increase in exhaust gas temperature due to fuel injection.

As described above, when the PM accumulation amount is equal to or greater than the first threshold value, the filter regeneration unit 50 automatically performs throttle of the intake throttle and post injection to regenerate the DPF 41.
Now, the filter regeneration means 50 regenerates the DPF 41 and controls to reduce the PM accumulation amount. As shown in FIG. 2, for example, if the DPF 41 is used for a long period of time, the PM accumulation amount gradually increases. May increase. Since the DPF 41 may break down when the PM accumulation amount becomes large, the work machine (backhoe) 1 of the present invention takes measures to prevent the PM accumulation amount from increasing as much as possible.

Hereinafter, a countermeasure when the PM accumulation amount increases beyond the first threshold will be described in detail.
The work machine (backhoe) 1 is provided with means for increasing the rotational speed of the engine 9 during the regeneration operation in the automatic regeneration mode. Specifically, during the activation of the automatic regeneration mode, when the PM accumulation amount becomes equal to or greater than the second threshold value (condition A) greater than the first threshold value, or the PM accumulation amount becomes greater than the first threshold value. Guiding means 51 is provided for guiding the engine 9 to manually increase the rotational speed when a certain time (for example, 1800 seconds) or longer continues (condition B).

  This guide means 51 is constituted by a program stored in the main ECU 33 as with the filter regeneration means 50. When the condition A or the condition B is established, the guide means 51 switches the screen of the display device 11 to a notification screen, and notifies the notification screen that the engine speed (hereinafter referred to as engine speed) is increased. Execute the display. For example, a message “Please increase the engine speed” is displayed on the notification screen.

  When the operator sees the notification screen, it is understood that the engine speed needs to be increased. Therefore, the operator manually operates the accelerator (accelerator lever) to increase the engine speed, thereby increasing the engine speed. Can be raised. When the engine speed is increased to a higher speed (for example, 1800 rpm or higher) than the idling speed (1000 rpm), the exhaust temperature rises and the regeneration of the DPF is promoted.

  Here, in order to increase the exhaust temperature efficiently, it is preferable to display the target value (1800 rpm) of the engine speed on the notification screen. For example, the notification screen displays “Please increase the engine speed by 1800 rpm or more”. When the target value of the engine speed is displayed on the notification screen, it is preferable that the target value can be arbitrarily set by operating the display device 11 or the like. Note that the target value of the engine speed is a value at which the exhaust temperature can be expected to rise due to the increase in the engine speed, and is preferably 1.5 times or more the idling speed, for example.

  In this way, the engine speed is not increased automatically but manually by the operator operating the accelerator lever. An operator can freely perform an acceleration operation (an increase in engine speed) that promotes the regeneration of the DPF automatically performed by the filter regeneration means 50, and the operation is disturbed by the regeneration of the DPF. Can be reduced.

  For example, when performing an acceleration operation (an increase in engine speed) for regeneration of the DPF, the operator first continues the operation using the operation lever 47 when the operation is performed using the operation lever 47, and the operation using the operation lever 47 is continued. After a moment, the engine speed can be increased by operating the accelerator lever, so that the operation of the operation lever 47 for the work is not disturbed by the regeneration of the DPF. The regeneration of the DPF can be promoted without deteriorating the properties.

Thus, if the operator operates the accelerator lever according to the notification screen and increases the engine speed, the PM accumulation amount is considered to be equal to or less than the first threshold value. However, when the operator does not notice the notification screen or does not operate the accelerator lever, the PM accumulation amount may further increase.
For this reason, the backhoe 1 is provided with an output limiting means 52 that limits the output of the engine during the playback operation in the automatic playback mode. The output limiting means 52 is configured by a program stored in the main ECU 33 as with the filter regeneration means 50.

  The output limiting means 52 limits the engine output while allowing the engine speed to increase or decrease when the PM accumulation amount becomes equal to or greater than a third threshold value that is greater than the second threshold value. For example, when the operation amount of the operation lever 47 is operated while the operator is in the vehicle, the load of the hydraulic pump that discharges the hydraulic oil changes according to the operation amount, and is linked to the change of the load of the hydraulic pump. The engine speed increases or decreases. The engine ECU 32 and the main ECU 33 perform fluctuations in the load on the hydraulic pump and increase / decrease in the engine speed.

The output limiting means 52 allows the engine speed to be increased or decreased by the operation lever 47 or the like (increase or decrease in the engine speed by flow control or the like) and can be freely changed. The engine ECU 32 is instructed to limit the output when the third threshold value is exceeded, and the engine ECU 32 adjusts the fuel injection time and the injection amount based on the output restriction command to thereby increase the maximum output (output) of the diesel engine 9. It is limited to a predetermined value or less (for example, 50% or less of normal output).

  In this way, by limiting the output of the diesel engine 9, an increase in the amount of PM deposited by the engine 9 is suppressed as much as possible. That is, the output limiting means 52 reduces the PM accumulation amount by the regeneration operation (decreases by combustion) and limits the output of the engine 9 (suppresses the amount of exhaust gas), thereby suppressing the increase in the PM accumulation amount. The increase in the total amount of PM deposition is suppressed.

Now, the increase of the engine speed and the engine output limitation are normally performed in a state where the operator is on board, and the reduction of the PM accumulation amount is promoted by these measures. However, there may be a situation where the operator is not on the work machine (backhoe) 1 and the engine is operating. In such a case, the PM deposition amount may increase.
Therefore, in the present invention, the boarding / alighting confirmation means 53 for confirming the boarding / alighting is confirmed, and the boarding / alighting of the operator is confirmed. On the other hand, if it is not in the boarding state (alighting state), while the “output restriction” is executed, the increase in the PM accumulation amount is suppressed by lowering the engine speed and stopping as described later.

  The boarding / alighting confirmation means 53 has, for example, a lever 55 that is swingably supported on the side of the driver's seat 10, and when the lever 55 is laid down and the boarding opening is closed, the operator is on board. A signal indicating the boarding state is output to the main ECU 33. Further, the boarding / exiting confirmation means 53 raises the lever 55 (makes it stand up) to open the boarding port, sets the boarding / unloading state, and outputs a signal indicating the boarding state to the main ECU 33. The signals of the boarding state and the getting off state are also output to the engine ECU 32 via a vehicle communication network N such as a controller area network (CAN communication).

Here, if the engine is operating in the state of getting off and the PM accumulation amount is not less than the third threshold value which is larger than the second threshold value, the engine ECU 32 (engine rotation control means) automatically Reduce the speed.
Specifically, after the engine is started, when the operation lever 47 is not operated regardless of the boarding state or the getting off state, the engine speed becomes the idling speed by the AI control of the main ECU 33.

  As described above, when the signal indicating the getting-off state is input under the condition that the engine speed is controlled to the idling speed (idling getting-off situation), the engine speed control means 32 causes the PM accumulation amount to be third. If it is determined whether or not it is equal to or greater than the threshold value and is equal to or greater than the third threshold value, the engine speed is set to zero and the engine is stopped as shown in FIG. On the other hand, if the PM accumulation amount is less than the third threshold value even in the idling state, the engine speed control means 32 maintains the idling speed.

As described above, according to the present invention, when the engine operates in the state of getting off and the PM accumulation amount is equal to or greater than the third threshold value (predetermined value), the engine rotation control means 32 automatically reduces the engine speed. Therefore, the exhaust gas exhausted from the engine is eliminated, and the PM accumulation amount can be prevented from increasing when the operator is not on the vehicle.
For example, in order to warm up the backhoe 1 (warm-up operation), after the worker gets on the backhoe 1 and starts the engine 9, the worker gets off from the backhoe 1 and may take a break for a while. If the operator forgets to warm up the backhoe 1 and keeps operating the engine 9 at idling speed for a long time, the PM accumulation amount gradually increases and the PM accumulation amount becomes DPF41. The DPF 41 may need to be replaced beyond the limit.

However, in the present invention, even when the engine is operating at idling speed without the operator getting on, such as in warm-up operation, when the PM accumulation amount becomes the third threshold value or more, Since the engine is stopped by the engine rotation control means 32, it is possible to prevent in advance that the PM accumulation amount due to forgetting warm-up operation or the like (PM accumulation amount exceeds the limit of collection of the DPF 41). it can. As a matter of course, the third threshold value, that is, the predetermined value for automatically starting to decrease the engine speed is set lower than the limit value for collecting the DPF 41 (a value that must be replaced). .

In the embodiment described above, as shown in FIG. 3, the engine speed is zeroed when the PM accumulation amount becomes equal to or greater than the third threshold by the engine rotation control means 32, but the engine is thus stopped. In addition, it is preferable to provide the backhoe 1 with a notification means 54 that notifies the engine stop or the like.
For example, the notification unit 54 is configured by a speaker or the like provided in the display device 11 of the backhoe 1, and outputs sound or a buzzer from the speaker when the PM accumulation amount exceeds the second threshold and approaches the third threshold. Then, the stop of the engine is notified (notified) in advance. Note that the notification unit 54 may be configured by a lamp, and when the PM accumulation amount exceeds the second threshold and approaches the third threshold, for example, the stop of the engine may be notified by blinking the lamp.

As described above, according to the present invention, the engine is stopped when the PM accumulation amount becomes equal to or greater than the third threshold after the notification means 54 notifies the engine stop. Even if you forget that you are operating, you can notice that you are warming up before stopping the engine.
Further, according to the present invention, when the PM accumulation amount is equal to or greater than the third threshold value and the operator is on board, the PM accumulation is performed by performing “notification of increase in engine speed” or “engine output restriction”. The increase in the amount can be suppressed, and when the operator is not on board, the increase in the PM accumulation amount can be suppressed by “decreasing the engine speed to zero”. That is, in the backhoe 1 of the present invention, it is possible to suppress an increase in the amount of accumulated PM in both the riding state and the non-riding state (the state where the vehicle is not boarded).

There is a case where the engine is started under a situation where the PM accumulation amount is already equal to or greater than the third threshold value. At this time, when the operator is on board after starting the engine, the engine output is limited as described above, and when the operator gets off, the engine speed is decreased as described above.
Here, when the PM accumulation amount is equal to or more than the third threshold value and the PM accumulation amount is equal to or more than the fourth threshold value, the backhoe 1 is quickly put on the display device 11 in a safe place while the operator is on board ( Move to the place where maintenance can be performed), stop the engine, and display that the service call (maintenance request) is to be made to the manufacturer, sales company, maintenance company, etc. For example, the display device 11 displays “Please promptly park the work machine in a safe place, turn off the engine and make a service call”. The fourth threshold value is larger than the third threshold value and smaller than the limit value for collecting the DPF 41, and indicates that the PM deposition amount is close to the limit value. In other words, the fourth threshold value indicates a situation where the DPF 41 needs to be promptly maintained. For example, when the limit value of the PM estimation amount is 100%, the fourth threshold value is set to 80 to 90%, or the third threshold value is used as a reference. Then, it is set to 50% or more of the difference (remaining allowable deposition value) between the third threshold value and the limit value.

  According to this, since the PM accumulation amount exceeds the third threshold and further exceeds the fourth threshold that requires maintenance of the DPF 41, a service call is made to the display device 11, so the PM accumulation amount is the limit value. The DPF 41 can be serviced before greeting. In addition, in the previous stage where the PM accumulation amount exceeds the fourth threshold value, processing for automatically reducing the engine speed when the third threshold value is exceeded, processing for limiting the engine output, processing for increasing the engine speed when the second threshold value is exceeded, Since the process of performing automatic regeneration can be performed above the first threshold value and the increase in the PM deposition amount is suppressed at each stage, the DPF 41 can be used over a long period of time.

[Second Embodiment]
In the first embodiment, the main ECU 33 is provided with AI control, and when the operation lever 47 is not operated, control is performed to automatically set the engine speed to the idling speed. As shown in FIG. 2, in the second embodiment, a backhoe 1 (main ECU 33) that does not include AI control will be described.

In the first embodiment, when the operator is in the getting-off state, there is AI control, so the engine speed is always the idling speed, but in the second embodiment, when there is no AI control, The engine speed is the value set by the accelerator lever. For example, when the engine speed is set to 1600 with the accelerator lever, the engine speed is 1600 even if the operator is in the exit state.

  When a signal indicating an unloading state is input under such circumstances, the engine rotation control means 32 determines whether the PM accumulation amount is greater than or equal to a third threshold value and determines the third value. When the threshold value is exceeded, as shown in FIG. 5, the engine speed set by the accelerator lever starts to gradually decrease. The engine speed control means 32 gradually decreases the engine speed after starting to decrease the engine speed, and when the engine speed reaches the idling speed, the engine speed is reduced to zero at once.

  On the other hand, the notification means 54 notifies that the engine is to be stopped after the PM accumulation amount becomes equal to or greater than the third threshold value and the engine speed starts to decrease. Specifically, when the engine rotation control means 32 starts to reduce the engine speed, the notification means 54 starts to notify the engine stop, and the engine is notified by the notification means 54 when the engine speed becomes the idling speed. Terminate the stop notification.

  According to the second embodiment, for example, even when the engine speed is set to be equal to or higher than the idling speed and the warm-up operation of the backhoe 1 is performed, the engine speed is decreased to zero. , It is possible to suppress an increase in the PM deposition amount. The operator can know from the notification means 54 that the engine speed is gradually decreasing, and it is also understood that the PM accumulation amount is not less than the third threshold value. For this reason, after getting on the backhoe 1, the operator can operate the accelerator lever to increase the engine speed to a target value or higher, thereby suppressing an increase in the amount of accumulated PM. be able to.

In the second embodiment described above, the engine speed is set by the accelerator lever even when the vehicle is getting off, so the set value of the accelerator lever is set much higher than the idling speed. When the rotational speed is high, the PM deposition amount may not increase.
As a modification of the second embodiment, in the region where the engine speed is high and the exhaust temperature rises, even if the PM accumulation amount exceeds the third threshold, the engine speed control means 32 reduces the engine speed. It is preferable to provide the main ECU 33 with priority control means 56 that is not performed. The priority control means 56 includes a program stored in the main ECU 33.

Specifically, the priority control unit 56 determines that the PM accumulation amount is higher when the engine speed is equal to or higher than a target value (for example, 1800 or higher) of the engine speed displayed on the notification screen of the guide unit 51 in the getting-off state. Even if it is greater than or equal to the third threshold value, the engine speed control means 32 does not perform control to lower the engine speed.
When the priority control means 56 is provided, as shown in FIG. 5 (a), when the vehicle is getting off, when the engine speed is equal to or higher than the idling speed and less than the target value of the engine speed indicated by the guide means 51. When the engine speed is reduced by the engine speed control means 32 and the engine speed is equal to or higher than the target value of the engine speed indicated by the guide means 51 as shown in FIG. The means 56 stops the control for lowering the engine speed.

  Since the high engine speed is maintained by this priority control means 56, the exhaust temperature rises and it is possible to maintain the regeneration of the DPF in the automatic regeneration mode. That is, in the second embodiment, the PM accumulation amount during the warm-up operation can be suppressed (when the PM accumulation amount is equal to or more than the third threshold value in the getting-off state, the engine speed is reduced to zero). However, when the engine speed by the accelerator lever is high, the engine speed can be maintained to increase the exhaust temperature, and the regeneration of the DPF can be prioritized.

As shown in FIG. 5 (c), in a situation where the engine speed is automatically lowered by the engine speed control means 32, the operator gets on and operates the accelerator lever to guide the engine speed. When the engine speed control value 32 is equal to or greater than the target value of the engine speed indicated by 51, the engine speed control means 32 cancels the control for automatically reducing the engine speed and sets the engine speed to a value based on the operation amount of the accelerator lever. It is preferable to do. In this case, the PM accumulation amount during the warm-up operation can be suppressed, but by operating the accelerator lever, the engine speed can be immediately returned to a high state and the regeneration of the DPF can be promoted. .

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
In automatic regeneration, whether to perform “throttle throttle” or “post injection” may be set as appropriate, and is not limited to the above. For example, the intake throttle may be initially throttled and then post injection may be performed, or only post injection may be performed.

In the above-described embodiment, the boarding / exiting confirmation means 53 is constituted by a lever provided around the driver's seat 10 and is used for confirming the boarding state and the boarding state of the operator by this lever. A lever used in the lever lock structure may also be used as the above-described boarding / alighting confirmation means 53.
In the case of a working machine such as the backhoe 1, an actuator is inadvertently operated when the operation lever 47 is moved. Therefore, a lever lock structure is provided to prevent this. In this lever lock structure, a lever lock lever is provided for checking the ride by swinging in the same manner as the lever described above. When the lever lock lever is laid sideways and the vehicle is on the board, the working oil is supplied to the actuator. Supply of hot water to the actuator is permitted when the lever for locking the lever stands up and the vehicle is getting off. The lever for locking the lever used in this lever lock mechanism may be used as the above-described boarding / exit confirmation means 53.

  Further, a pressure sensor may be provided in the seat portion or the backrest portion of the driver's seat, and this pressure sensor may be used as the boarding / alighting confirmation means 53. In this case, when the pressure sensor is working to detect the pressure, the boarding state is entered, and when the pressure sensor is not detecting the pressure, the boarding state is entered. In addition, the boarding / alighting confirmation means 53 may confirm boarding with a camera other than a lever or a sensor.

  The control program for configuring the filter regeneration unit 50, the guide unit 51, the output limiting unit 53, the priority control unit 56, etc. may be stored in the engine ECU 32 or the main ECU 33, or the work machine You may store in the electronic equipment mounted in (backhoe 1). Further, the engine ECU 32 (engine rotation control means) and the main ECU 33 may be integrated.

DESCRIPTION OF SYMBOLS 1 Backhoe 2 Traveling device 3 Revolving body 4 Traveling body 5 Dozer 6 Swivel bearing 7 Swivel stand 8 Working device 9 Diesel engine 10 Driver's seat 11 Display device 12 Cabin 13 Support bracket 14 Swing bracket 15 Boom 16 Arm 17 Bucket 18 Boom cylinder 19 Arm Cylinder 20 Bucket cylinder 30 Exhaust manifold 31 Exhaust gas purification device 32 Engine ECU (engine rotation control means)
33 Main ECU
34 Cylinder 35 Intake port 36 Exhaust port 37 Intake valve 38 Exhaust valve 39 Intake manifold 40 Silencer 41 DPF
42 Inlet pressure sensor 43 Outlet pressure sensor 44 Differential pressure sensor 45 Exhaust temperature sensor 46 Control unit 47 Operation lever 50 Filter regeneration means 51 Guide means 52 Output restriction means 53 Getting in / out confirmation means 54 Notification means 55 Lever 56 Priority control means

Claims (5)

Exhaust gas purification device having a filter for collecting particulate matter contained in exhaust gas discharged from a diesel engine, and filter regeneration means for burning and removing particulate matter deposited on the filter of the exhaust gas purification device And boarding / alighting confirmation means for confirming boarding or getting off,
An engine that automatically reduces the engine speed when the engine is operated in a state where the getting-off confirmation means is confirmed to get off and the amount of particulate matter deposited on the filter is a predetermined value or more. A work machine comprising rotation control means.   2. The engine rotation control unit according to claim 1, wherein the engine rotation control means lowers the engine rotation speed to zero when the engine rotation speed in a dismounting state is an idling rotation speed and the accumulation amount is a predetermined value or more. The working machine described.   The engine rotation control means is configured to gradually reduce the engine rotation speed to the idling rotation speed to zero when the engine rotation speed in the getting-off state is equal to or higher than the idling rotation speed and the accumulation amount is equal to or greater than a predetermined value. The working machine according to claim 1, characterized in that:   When the engine is operating in a state where the boarding is confirmed by the boarding / alighting confirmation means, and the amount of particulate matter deposited on the filter is greater than or equal to a predetermined value, the engine speed is allowed to increase or decrease. The working machine according to any one of claims 1 to 3, further comprising output limiting means for limiting the output of the engine.   The work machine according to any one of claims 1 to 4, further comprising a notifying unit that notifies that the engine speed is to be lowered when the engine speed is lowered by the engine speed control means.

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