JP7482816B2 - Work Machine - Google Patents

Description

The present invention relates to a work machine such as a hydraulic excavator equipped with a device for collecting particulate matter.

Hydraulic excavators equipped with aftertreatment devices that incorporate a catalyzed soot filter (CSF) as a trap for particulate matter (hereinafter referred to as "PM") contained in engine exhaust gases have been known.

Patent Document 1, which shows a hydraulic excavator equipped with a CSF, discloses a technology that performs a regeneration process to burn PM accumulated in the CSF by post-injecting fuel, and judges whether the fuel supplied to the engine is good or bad based on the fluctuation in the differential pressure before and after the CSF after the regeneration process has been performed.

JP 2015-52297 A

However, factors that cause the pressure difference before and after the CSF to fluctuate include not only the quality of the fuel, but also the operating conditions of the work machine and the accumulation of ash in the CSF. Therefore, in Patent Document 1, it may not be possible to accurately determine whether the fuel is good or bad.

The present invention was made in consideration of the above-mentioned circumstances, and its purpose is to provide a work machine that can more accurately determine whether the fuel supplied to the engine is good or bad.

In order to achieve the above object, the present invention provides a work machine including an engine, an aftertreatment device having an internal filter for collecting particulate matter contained in exhaust gas from the engine, a differential pressure sensor for detecting the differential pressure of exhaust gas before and after the filter, and a controller capable of executing a differential pressure regeneration process for regenerating the filter by post-injection of fuel when the differential pressure detected by the differential pressure sensor is equal to or greater than a predetermined pressure, and a time regeneration process for regenerating the filter by post-injection of fuel when a predetermined time has elapsed, the controller controls the executed differential pressure regeneration process and time regeneration process as regeneration processes. The device is characterized in that it has a memory for storing the differential pressure, and when both a first condition indicating that the latest regeneration process stored in the memory is the differential pressure regeneration process and a second condition indicating that the elapsed time from the time when the latest differential pressure regeneration process stored in the memory was performed is a predetermined time or more are satisfied, it executes a new differential pressure regeneration process, and when the differential pressure detected by the differential pressure sensor is the predetermined pressure or more, it executes a first notification process that notifies the possibility that inferior fuel is being supplied to the engine when the differential pressure detected by the differential pressure sensor is the predetermined pressure or more, it satisfies the first condition but does not satisfy the second condition.

According to the present invention, in a work machine equipped with a filter that collects particulate matter, it is possible to more accurately determine whether the fuel supplied to the engine is good or bad. Note that problems, configurations, and effects other than those described above will become clear from the description of the embodiment below.

FIG. 2 is a side view of the hydraulic excavator. FIG. 2 is a diagram showing a drive circuit of a hydraulic excavator. FIG. 2 is a hardware configuration diagram of a hydraulic excavator. 3A to 3C are diagrams illustrating examples of data structures of various information stored in a memory. 13 is a flowchart of a playback control process. 13 is a flowchart of a condition determination process. FIG. 11 is a diagram illustrating an example of a relationship between a predetermined pressure and a predetermined time.

An embodiment of a hydraulic excavator 1 (working machine) according to the present invention will be described with reference to the drawings. Note that specific examples of the working machine are not limited to the hydraulic excavator 1, and may be wheel loaders, cranes, dump trucks, etc. Furthermore, unless otherwise specified, the terms front, back, left, right, and front in this specification are based on the viewpoint of an operator who is riding on and operating the hydraulic excavator 1.

Figure 1 is a side view of a hydraulic excavator 1. As shown in Figure 1, the hydraulic excavator 1 includes a lower traveling body 2 and an upper rotating body 3 supported by the lower traveling body 2. The lower traveling body 2 and the upper rotating body 3 are examples of a vehicle body.

The lower traveling body 2 is equipped with a pair of left and right crawlers 8 that are endless tracks. The pair of left and right crawlers 8 rotate independently when driven by a traveling motor (not shown). As a result, the hydraulic excavator 1 travels. However, the lower traveling body 2 may be of a wheeled type instead of the crawlers 8.

The upper rotating body 3 is supported on the lower running body 2 so that it can rotate by a rotating motor (not shown). The upper rotating body 3 mainly comprises a rotating frame 5 that serves as a base, a front work machine 4 (working device) that is attached to the front center of the rotating frame 5 so that it can rotate in the vertical direction, a cab (operator's seat) 7 that is located on the front left side of the rotating frame 5, and a counterweight 6 that is located at the rear of the rotating frame 5.

The front work implement 4 includes a boom 4a supported on the upper rotating body 3 so that it can be raised and lowered, an arm 4b supported rotatably at the tip of the boom 4a, a bucket 4c supported rotatably at the tip of the arm 4b, a boom cylinder 4d that drives the boom 4a, an arm cylinder 4e that drives the arm 4b, and a bucket cylinder 4f that drives the bucket 4c. The counterweight 6 is used to balance the weight of the front work implement 4, and is a heavy object that has an arc shape when viewed from above.

The cab 7 defines an internal space in which an operator who operates the hydraulic excavator 1 sits. The internal space of the cab 7 also contains a seat on which the operator sits, and operating devices that are operated by the operator seated in the seat.

The operating device receives operations from an operator to operate the hydraulic excavator 1. When the operator operates the operating device, the lower traveling body 2 travels, the upper rotating body 3 rotates, and the front working machine 4 operates. Specific examples of the operating device include a lever, a steering wheel, an accelerator pedal, a brake pedal, a switch, etc.

The cab 7 is also provided with a monitor 9 (see FIG. 3). The monitor 9 displays information (text, images) under the control of the controller 20. The monitor 9 is an example of an alarm device that notifies the operator of the cab 7 of information. However, specific examples of the alarm device are not limited to the monitor 9, and may be a speaker, an LED lamp, etc.

Figure 2 is a diagram showing the drive circuit of the hydraulic excavator 1. As shown in Figure 2, the hydraulic excavator 1 mainly comprises an engine 10, a hydraulic pump 11, an exhaust pipe 12, an aftertreatment device 130 that has an internal CSF (Catalyzed Soot Filter) 13, which is an example of a filter, and also functions as a silencer, a differential pressure sensor 14, and a temperature sensor 15.

The engine 10 generates driving force to rotate the hydraulic pump 11 by mixing and burning air taken in from outside the hydraulic excavator 1 with fuel injected from an injector 16 (see FIG. 3), and discharges exhaust gas into an exhaust pipe 12. The engine 10 is, for example, a diesel engine that uses diesel as fuel.

More specifically, the engine 10 generates driving force by repeating the following strokes: an intake stroke in which the piston descends to draw air into the cylinder; a compression stroke in which the piston ascends to top dead center to compress the air in the cylinder; a combustion stroke in which fuel is injected from the injector 16 into the compressed high-temperature, high-pressure air and ignites it; and an exhaust stroke in which the air expands due to combustion, forcing the piston down to bottom dead center and discharging exhaust gas into the exhaust pipe 12.

The hydraulic pump 11 is connected to the output shaft of the engine 10. The hydraulic pump 11 supplies hydraulic oil stored in a hydraulic oil tank (not shown) to the hydraulic actuators (travel motor, swing motor, boom cylinder 4d, arm cylinder 4e, and bucket cylinder 4f) using the driving force generated by the engine 10.

The exhaust pipe 12 extends from the engine 10 to the outside of the hydraulic excavator 1. The exhaust pipe 12 forms a passage through which exhaust gas discharged from the engine 10 is discharged to the outside of the hydraulic excavator 1. The post-treatment device 130, which has a CSF 13 inside, is disposed midway through the exhaust pipe 12. The CSF 13 collects PM from the exhaust gas passing through the exhaust pipe 12. The CSF 13 is configured to be detachable from the exhaust pipe 12.

The differential pressure sensor 14 is connected to the exhaust pipe 12 upstream of the CSF 13 in the exhaust gas flow and downstream of the CSF 13 in the exhaust gas flow. The differential pressure sensor 14 detects the pressure difference (differential pressure ΔP) before and after the CSF 13 and outputs a differential pressure signal indicating the detection result to the controller 20.

The temperature sensor 15 is installed in the exhaust pipe 12, upstream of the CSF 13 in the flow of exhaust gas. The temperature sensor 15 detects the temperature of the exhaust gas flowing through the exhaust pipe 12, and outputs a temperature signal indicating the detection result to the controller 20.

Figure 3 is a hardware configuration diagram of the hydraulic excavator 1. Figure 4 is a diagram showing an example of the data structure of the information stored in the memory 22 (operation information 23, playback history information 24, and maintenance information 25).

As shown in FIG. 3, the hydraulic excavator 1 includes a controller 20. The controller 20 includes, for example, a CPU (Central Processing Unit) 21 and a memory 22. The controller 20 realizes the processing described below by the CPU 21 reading and executing program code stored in the memory 22.

However, the specific configuration of the controller 20 is not limited to this, and may be realized by hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

The controller 20 may also include an engine controller that controls the operation of the engine 10, and a control controller that controls other components of the hydraulic excavator 1 (e.g., the hydraulic pump 11, the monitor 9, etc.). However, in this embodiment, the engine controller and the control controller are not distinguished and are referred to as "controller 20."

The controller 20 controls the overall operation of the hydraulic excavator 1. More specifically, the controller 20 acquires a differential pressure signal output from the differential pressure sensor 14 and a temperature signal output from the temperature sensor 15, and controls the monitor 9 and the injector 16 based on the acquired various signals. The controller 20 also includes a system clock that outputs the current time. Furthermore, the memory 22 stores operation information 23, regeneration history information 24, and maintenance information 25.

As shown in FIG. 4A, the operation information 23 includes multiple sets of detection times and exhaust temperatures that are associated with each other. The controller 20 repeatedly executes a process of associating the temperature detected by the temperature sensor 15 (exhaust temperature) with the detection time of the exhaust temperature by the temperature sensor 15 and adding the associated temperature to the operation information 23 at a predetermined time interval.

The operation information 23 indicates the operating status of the hydraulic excavator 1. That is, a time period when the exhaust temperature is relatively high is a time period when the hydraulic excavator 1 is performing high-load operations (e.g., traveling at high speeds, driving the front work implement 4). On the other hand, a time period when the exhaust temperature is relatively low is a time period when the hydraulic excavator 1 is performing low-load operations (e.g., idling).

As shown in FIG. 4B, the regeneration history information 24 includes regeneration times and regeneration types that are associated with each other. When the controller 20 executes a differential pressure regeneration process or a time regeneration process (hereinafter, these are collectively referred to as "regeneration processes") described below, the controller 20 updates the regeneration history information 24 with the time at which the regeneration process was executed (regeneration time) and whether the differential pressure regeneration process or the time regeneration process was executed (regeneration type). That is, the regeneration history information 24 is information indicating the regeneration process executed immediately before, out of the differential pressure regeneration process and the time regeneration process. In other words, the regeneration history information 24 is information indicating the latest regeneration process. Note that in this embodiment, an example will be described in which the regeneration history information 24 is updated (overwritten) in steps S14 and S26 described below, but a configuration in which a record is added each time a regeneration process is executed may also be used.

As shown in FIG. 4(C), the maintenance information 25 includes a cleaning time, which is the most recent time when the CSF 13 was cleaned. That is, the controller 20 updates the maintenance information 25 with the time (cleaning time) when an operation indicating that the CSF 13 has been cleaned was performed on the operating device. Note that, in this embodiment, an example is described in which the maintenance information 25 is updated (overwritten) when the CSF 13 is cleaned, but a configuration in which a record is added each time the CSF 13 is cleaned may also be used.

Next, the processing of the controller 20 will be described with reference to Figures 5 to 7. Figure 5 is a flowchart of the regeneration control processing. Figure 6 is a flowchart of the condition determination processing. Figure 7 is a diagram showing an example of the relationship between the predetermined pressure _Pth and the predetermined time _tDPR . The controller 20 repeatedly executes the regeneration control processing at predetermined time intervals while the engine 10 is running.

The time when the playback control process starts is designated as tx, and the operation information 23, playback history information 24, and maintenance information 25 shown in FIG. 4 are stored in the memory 22. Also, it is assumed that a timer with a predetermined time is set at the timing when the playback process was executed immediately before (S14, S26).

First, the controller 20 waits to execute the following process until the timer times out or the differential pressure ΔP detected by the differential pressure sensor 14 becomes equal to or greater than a predetermined pressure _Pth (S11: No & S12: No). The timer times out indicates that a predetermined time has elapsed since the previous regeneration process was executed. The differential pressure ΔP becomes equal to or greater than the predetermined pressure _Pth indicates that PM has accumulated on the surface of the CSF 13, causing a decrease in the flow rate of exhaust gas passing through the CSF 13 (deterioration in the performance of the CSF 13).

If the timer times out (S11: Yes) before the pressure difference ΔP becomes equal to or greater than the predetermined pressure _Pth (S12: No), the controller 20 executes a time-based regeneration process (S13). The time-based regeneration process is a process for regenerating the CSF 13 every time a predetermined time has elapsed.

"Regeneration of CSF 13" is a process for burning PM accumulated in CSF 13 by increasing the exhaust temperature. The controller 20 forcibly increases the temperature of the exhaust gas by having the injector 16 perform post-injection. More specifically, the controller 20 causes the injector 16 to inject fuel (post-injection) during the exhaust stroke in addition to the combustion stroke during the time regeneration process.

Next, the controller 20 updates the playback history information 24 by setting the playback time to "current time" and the playback type to "time playback," and sets a timer with a predetermined time (S14), and ends the playback control process.

On the other hand, if the differential pressure ΔP detected by the differential pressure sensor 14 becomes equal to or greater than a predetermined pressure _Pth (S12: Yes) before the timer times out (S11: No), the controller 20 determines whether or not an abnormality has occurred in the engine 10 (S15). If the detection results of a plurality of sensors (e.g., the temperature sensor 15, the rotation speed sensor, etc.) are outside the normal range, the controller 20 determines that an abnormality has occurred in the engine 10. The process of step S15 is already well known, so a detailed description thereof will be omitted.

If the controller 20 determines that an abnormality has occurred in the engine 10 (S15: Yes), it causes the monitor 9 to display the abnormality in the engine 10 (S16). Displaying on the monitor 9 is one example of a notification. However, the specific method of notification is not limited to displaying information on the monitor 9, and may be turning on an LED lamp, outputting a guide voice from a speaker, transmitting information to an external device via a communication network, etc. The same applies to steps S27 and S28 described below.

On the other hand, if the controller 20 determines that no abnormality has occurred in the engine 10 (i.e., the engine 10 is operating normally) (S15: No), the controller 20 executes the condition determination process shown in FIG. 6 (S17). The condition determination process is a process for determining whether or not the conditions for executing the differential pressure regeneration process are satisfied.

As shown in FIG. 6, the controller 20 determines whether the first condition (S21), the second condition (S22), the third condition (S23), and the fourth condition (S24) are satisfied. The first to fourth conditions are conditions for determining whether to execute the differential pressure regeneration process (S25), the first notification process (S27), or the second notification process (S28).

The first condition is that the regeneration history information 24 indicates differential pressure regeneration processing (in other words, the most recent regeneration processing is a differential pressure regeneration processing). That is, the controller 20 refers to the regeneration history information 24 and determines whether or not the regeneration type is set to "differential pressure regeneration" (S21). Then, if the regeneration type is set to "differential pressure regeneration", the controller 20 determines that the first condition is met (S21: Yes). On the other hand, if the regeneration type is set to "time regeneration", the controller 20 determines that the first condition is not met (S21: No).

The second condition is that the elapsed time Δt from the time when the latest differential pressure regeneration process was performed is equal to or greater than a predetermined time t _DPR . That is, the controller 20 calculates the difference between the current time tx obtained from the system clock and the regeneration time tn of the regeneration history information 24 as the elapsed time Δt, and compares it with the predetermined time t _DPR (S22). Then, the controller 20 determines that the second condition is met if the calculated elapsed time Δt is equal to or greater than the predetermined time t _DPR (S22: Yes). On the other hand, the controller 20 determines that the second condition is not met if the calculated elapsed time Δt is less than the predetermined time t _DPR (S22: No).

The predetermined time t _DPR is set to a time required for the differential pressure ΔP detected by the differential pressure sensor 14 to increase from 0 to the predetermined pressure _Pth when the engine 10 is driven using fuel with predetermined properties, as shown in Fig. 7. This predetermined time t _DPR is determined by experiments or simulations, and is stored in the memory 22 in advance.

The third condition is that the exhaust temperature T detected by the temperature sensor 15 during the elapsed time Δt is less than the predetermined temperature T _PM . That is, the controller 20 compares each of the exhaust temperatures T included in the comparison period going back from the current time tx by the elapsed time Δt, among the multiple exhaust temperatures included in the operation information 23, with the predetermined temperature T _PM (S23). Then, the controller 20 determines that the third condition is satisfied when all the exhaust temperatures T included in the comparison period are less than the predetermined temperature T _PM (S23: Yes). On the other hand, the controller 20 determines that the third condition is not satisfied when some of the exhaust temperatures T included in the comparison period are less than the predetermined temperature T _PM (S23: No).

The predetermined temperature T _PM is set to a temperature of the exhaust gas (e.g., 250° C.) sufficient to combust the PM accumulated in the CSF 13. The temperature of the exhaust gas discharged from the engine 10 becomes higher as the hydraulic excavator 1 operates under a higher load, and becomes lower as the hydraulic excavator 1 operates under a lower load.

When the hydraulic excavator 1 continues to operate under high load, the resulting high-temperature exhaust gas naturally regenerates the CSF 13 (self-regeneration). Hereinafter, the time regeneration process and differential pressure regeneration process, which perform post-injection to forcibly regenerate the CSF 13, will be referred to as "forced regeneration" to distinguish them from self-regeneration.

The fourth condition is that the usage time t _USE since the last cleaning of the CSF 13 is less than the maintenance time t _REC . That is, the controller 20 calculates the difference between the current time tx obtained from the system clock and the cleaning time ta in the maintenance information 25 as the usage time t _USE , and compares it with the maintenance time t _REC (S24). Then, the controller 20 determines that the fourth condition is met if the calculated usage time t _USE is less than the maintenance time t _REC (S24: Yes). On the other hand, the controller 20 determines that the fourth condition is not met if the calculated usage time t _USE is equal to or greater than the maintenance time t _REC (S24: No).

The maintenance time t _REC is set to, for example, the time until impurities (e.g., metal-derived ash, etc.) that cannot be removed by the regeneration process accumulate and the performance of the CSF 13 deteriorates. In other words, the maintenance time t _REC is set to the limit time until the CSF 13 can be regenerated by the regeneration process.

When the controller 20 determines that the first condition is not satisfied (S21: No), it executes the differential pressure regeneration process regardless of the determination results of the second to fourth conditions (S25). The differential pressure regeneration process executes post-injection like the time regeneration process. That is, the time regeneration process and the differential pressure regeneration process are common in that they both execute post-injection. On the other hand, the differential pressure regeneration process differs from the time regeneration process, which is executed when a predetermined time has elapsed, in that it is executed when the differential pressure ΔP becomes equal to or greater than a predetermined pressure _Pth .

Next, the controller 20 updates the regeneration history information 24 by setting the regeneration time to "current time" and the regeneration type to "differential pressure regeneration", resets the timer that has been set to a predetermined time (S26), and ends the condition determination process. That is, in step S26, the timer is canceled and then started again. Also, if the controller 20 determines that all of the first condition, second condition, and third condition are satisfied (S21: Yes & S22: Yes & S23: Yes), it executes the processes of steps S25 and S26.

The second and third conditions are both satisfied when the hydraulic excavator 1 continues to operate at a low load and is estimated not to be performing self-regeneration. In such a case, PM also continues to accumulate in the CSF 13, so it is quite conceivable that the differential pressure ΔP will reach or exceed the predetermined pressure _Pth before the timer times out (S11: No & S12: Yes). Therefore, even if the latest regeneration process is a differential pressure regeneration process (S21: Yes), it is desirable to execute the differential pressure regeneration process (S25).

In addition, when the controller 20 determines that the first condition is satisfied but at least one of the second condition and the third condition is not satisfied (S21: Yes & S22: No/S23: No), it determines whether the fourth condition is satisfied (S24) instead of performing the differential pressure regeneration process (S25).

The first condition is satisfied but the second condition is not satisfied when the elapsed time Δt from the last execution of the differential pressure regeneration process until the differential pressure ΔP becomes equal to or greater than the predetermined pressure _Pth is extremely short.The third condition is not satisfied when a high-load operation has been executed between the last regeneration process and the present, and it is estimated that self-regeneration of the CSF 13 is being performed.

In such a case, poor quality fuel may be supplied to the engine 10, causing a very high PM content in the exhaust gas, or impurities (e.g., ash) that cannot be removed by the regeneration process may have accumulated in the CSF 13, and it is believed that the CSF 13 will not be regenerated even if the differential pressure regeneration process is performed.

The fourth condition is met when PM accumulates in the CSF 13 before the maintenance time _tREC has elapsed, and therefore there is a possibility that inferior fuel is being supplied to the engine 10. When the fourth condition is met (S24: Yes), the controller 20 displays a message on the monitor 9 indicating the possibility that inferior fuel is being supplied to the engine 10 (S27), and ends the condition determination process. The process of step S27 is an example of a first notification process.

On the other hand, the fourth condition is not satisfied after the maintenance time _tREC has elapsed, and therefore impurities that cannot be removed by the regeneration process may have accumulated in the CSF 13. Therefore, when the fourth condition is not satisfied (S24: No), the controller 20 displays a message on the monitor 9 prompting the user to clean the CSF 13 (S28) and ends the condition determination process. The process of step S28 is an example of a second notification process.

Then, upon seeing the message displayed in step S28, the operator removes the CSF 13, cleans it (for example, by washing it with water), reattaches the cleaned CSF 13, and performs an operation on the operation device indicating that the CSF 13 has been cleaned. The controller 20 also updates the cleaning time in the maintenance information 25 with the time when the operation was performed by the operator.

According to the above embodiment, if the differential pressure regeneration process is repeatedly executed before the predetermined time t _DPR has elapsed (S21: Yes & S22: No), it is determined that there is a possibility that inferior fuel is being used. In this way, by combining the first condition and the second condition, it is possible to more accurately determine whether the fuel supplied to the engine 10 is good or bad.

In addition, according to the above embodiment, if the differential pressure regeneration process is repeatedly executed even though self-regeneration is being performed (S21: Yes & S23: No), it is determined that there is a possibility that inferior fuel is being used. In this way, by combining the third condition with the first and second conditions, it is possible to more accurately determine whether the fuel supplied to the engine 10 is good or bad.

In addition, according to the above embodiment, whether poor quality fuel is being used or whether ash or the like has accumulated in the CSF 13 is determined based on whether the fourth condition is met. This makes it possible to more accurately determine whether the fuel supplied to the engine 10 is good or bad.

Furthermore, according to the above embodiment, by determining whether the engine 10 is operating normally (S15) prior to determining the first to fourth conditions, it is possible to more accurately determine whether the fuel supplied to the engine 10 is good or bad.

In step S23, instead of all exhaust temperatures T included in the comparison period, an average value of the exhaust temperatures T during the comparison period may be compared with the predetermined temperature _TPM . In addition, in the condition determination process, one of steps S22 and S23 may be omitted. Furthermore, in the condition determination process, steps S24 and S28 may be omitted.

The above-described embodiments are illustrative examples of the present invention, and are not intended to limit the scope of the present invention to these embodiments. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the present invention.

REFERENCE SIGNS LIST 1 Hydraulic excavator 2 Lower travel unit 3 Upper rotating unit 4 Front work unit 4a Boom 4b Arm 4c Bucket 4d Boom cylinder 4e Arm cylinder 4f Bucket cylinder 5 Swivel frame 6 Counterweight 7 Cab 8 Crawler 9 Monitor 10 Engine 11 Hydraulic pump 12 Exhaust pipe 14 Differential pressure sensor 15 Temperature sensor 16 Injector 20 Controller 22 Memory 23 Operation information 24 Regeneration history information 25 Maintenance information 130 Aftertreatment device

Claims (5)

The engine,
an aftertreatment device having a filter therein for collecting particulate matter contained in exhaust gas from the engine;
a differential pressure sensor that detects a differential pressure of exhaust gas before and after the filter;
a controller capable of executing a differential pressure regeneration process for regenerating the filter by post-injection of fuel when the differential pressure detected by the differential pressure sensor is equal to or higher than a predetermined pressure, and a time regeneration process for regenerating the filter by post-injection of fuel when a predetermined time has elapsed,
The controller:
a memory for storing the executed differential pressure regeneration process and the executed time regeneration process as regeneration processes;
executes a new differential pressure regeneration process when the differential pressure detected by the differential pressure sensor is equal to or greater than the predetermined pressure and satisfies both a first condition indicating that the latest regeneration process stored in the memory is the differential pressure regeneration process and a second condition indicating that the elapsed time from the time when the latest differential pressure regeneration process stored in the memory was executed is equal to or greater than a predetermined time;
a first notification process is executed to notify a possibility that inferior fuel is being supplied to the engine when the differential pressure detected by the differential pressure sensor is equal to or greater than the specified pressure, thereby satisfying the first condition, but not satisfying the second condition. 2. The work machine according to claim 1,
A temperature sensor is provided to detect the temperature of the exhaust gas.
The controller:
executes the differential pressure regeneration process when all of the first condition, the second condition, and a third condition indicating that the temperature detected by the temperature sensor during the elapsed time is lower than a predetermined temperature are satisfied;
A work machine comprising: a work machine that executes the first notification process when the first condition is satisfied and at least one of the second condition and the third condition is not satisfied. 3. The work machine according to claim 2,
the memory stores maintenance information indicating the last time the filter was cleaned;
When the first condition is satisfied and at least one of the second condition and the third condition is not satisfied, the controller:
execute the first notification process when a fourth condition is satisfied, that is, the usage time from the time indicated in the maintenance information to the present is less than the maintenance time;
a second notification process for notifying a user to clean the filter when the fourth condition is not satisfied; 2. The work machine according to claim 1,
a predetermined time period that is a time period required for a differential pressure detected by the differential pressure sensor to increase from 0 to the predetermined pressure when the engine is driven using fuel having predetermined properties. 2. The work machine according to claim 1,
The working machine is characterized in that the controller determines whether or not the first condition and the second condition are satisfied when the differential pressure detected by the differential pressure sensor is equal to or greater than the predetermined pressure and the engine is operating normally.

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