JP2013113263A - Working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency in the regeneration of a diesel particulate filter (DPF) provided in a discharge passage of exhaust gas.SOLUTION: In a working vehicle in which a diesel engine is mounted, which includes a DPF (46b) for catching particulate materials (PMs) in exhaust gas, when the quantity of PM deposited in the DPF (46b) becomes equal to or more than a prescribed quantity (P), an ECU (100) outputs a signal for automatically regenerating the DPF (46b). If the automatic regeneration cannot be executed. automatic regeneration execution is outputted continuously. If the automatic regeneration cannot be started even after automatic regeneration execution is outputted a plurality of times, the ECU (100) outputs a signal for performing manual regeneration.

Description

  The present invention relates to a work vehicle equipped with a diesel engine equipped with a diesel particulate filter (DPF).

  When the diesel particulate filter (DPF) is regenerated, it is configured to select and switch between execution in automatic regeneration or execution in manual regeneration with a selection unit (see, for example, Patent Document 1).

JP 2010-84686 A

  In the above-described technique, when automatic regeneration is selected, if automatic regeneration is not performed due to work conditions, for example, conditions such as low exhaust gas temperature, and the situation continues as it is, the DPF is immediately accumulated without being regenerated. The tolerance is reached. The subject of this invention is providing the work vehicle carrying the diesel engine which eliminates the above malfunctions.

The above object of the present invention is achieved by the following configuration.
That is, according to the first aspect of the present invention, in a work vehicle equipped with a diesel engine equipped with a DPF (46b) that collects particulate matter (PM) in exhaust gas, the amount of PM deposited in the DPF (46b) When the predetermined amount (P) or more is reached, the ECU (100) outputs a signal for performing automatic regeneration of the DPF (46b). When this automatic regeneration cannot be performed, the automatic regeneration is continuously output and automatic regeneration is performed. The ECU (100) is configured to output a signal for performing manual regeneration when automatic regeneration cannot be started even if execution is output a plurality of times.

  According to the first aspect of the present invention, when the PM accumulation amount in the DPF (46b) becomes equal to or larger than the predetermined amount (P), the ECU (100) outputs a signal for automatically regenerating the DPF (46b). When this automatic reproduction cannot be executed, the automatic reproduction execution is continuously output. If the automatic regeneration cannot be started even if the automatic regeneration execution is performed a plurality of times, the ECU (100) outputs a signal for performing the manual regeneration.

  According to a second aspect of the present invention, the manual regeneration execution content output from the ECU (100) is displayed on the liquid crystal display unit (68) of the driving unit. This is a working vehicle.

The operation of the second aspect displays the content of the manual regeneration output output from the ECU (100) on the liquid crystal display unit (68) of the driving unit.
According to a third aspect of the present invention, when the manual regeneration is not executed for a predetermined time (Q) after the display for prompting the manual regeneration on the liquid crystal display unit (68), a signal for performing automatic regeneration again from the ECU (100). The work vehicle according to claim 2, wherein the work vehicle is configured to output.

  According to the third aspect of the present invention, when manual regeneration is not executed for a predetermined time (Q) after the display for prompting manual regeneration on the liquid crystal display unit (68), a signal for performing automatic regeneration is output again from the ECU (100). To do.

  Since the present invention is configured as described above, according to the first aspect of the present invention, when the automatic reproduction cannot be executed, the automatic reproduction execution is continuously output, so that the automatic reproduction can be started immediately if the conditions are satisfied. Further, when automatic regeneration cannot be started even if the automatic regeneration execution is output a plurality of times, a signal for performing manual regeneration is output, so that it is possible to prevent the PM accumulation amount of the DPF (46b) from reaching an allowable amount.

According to the second aspect of the present invention, the manual regeneration execution content output from the ECU (100) is displayed on the liquid crystal display section (68) of the operation section, so that if there is an opportunity, manual regeneration can be performed immediately.
In the third aspect of the invention, when the manual regeneration is not executed for a predetermined time (Q) after the display for prompting the manual regeneration on the liquid crystal display unit (68), the signal for performing the automatic regeneration again from the ECU (100). Since the automatic regeneration can be performed immediately after the conditions are satisfied, it is possible to prevent the PM deposition amount of the DPF (46b) from reaching the allowable amount.

Overall configuration diagram of accumulator fuel injection system Diagram showing the relationship between engine speed and output torque in control mode Left side view of tractor Top view of tractor Schematic diagram of intake and exhaust systems Flow chart of playback Flow chart of playback Flow chart of playback Schematic diagram of engine and exhaust system Schematic diagram of engine intake and exhaust systems Radiator front view (A) Front view of tractor, (b) Side view of tractor, (c) Cross section of duct, (d) Cross section of duct Relationship diagram between work implement hydraulic operation and fuel injection amount

The best mode for carrying out the present invention will be described.
FIG. 1 is an overall configuration diagram of a pressure accumulation type fuel injection device. The accumulator type fuel injection device is applied to, for example, a multi-cylinder diesel engine, but may be a gasoline engine. The accumulator fuel injection device pressurizes the common rail 1 that accumulates high-pressure fuel corresponding to the injection pressure, the pressure sensor 2 attached to the common rail 1, and the fuel pumped up from the fuel tank 3, and pumps the fuel to the common rail 1. A high-pressure pump 4, a fuel injection nozzle 6 for injecting high-pressure fuel accumulated in the common rail 1 into the cylinder 5 of the engine E, a control device (ECU) for controlling the operation of the high-pressure pump 4, the fuel injection nozzle 6 and the like Consists of ECU is an abbreviation for engine control unit.

Thus, the common rail 1 injects fuel to each cylinder 5 of the engine E, and makes the fuel supply a required pressure.
The fuel in the fuel tank 3 is sucked into the high-pressure pump 4 driven by the engine E through the fuel filter 7 through the suction passage, and the high-pressure fuel pressurized by the high-pressure pump 4 is guided to the common rail 1 through the discharge passage 8. Stored.

  The high-pressure fuel in the common rail 1 is supplied to the fuel injection nozzles 6 for the number of cylinders through the high-pressure fuel supply passages 9, and the fuel injection nozzles 6 are operated to the cylinders based on commands from the ECU 100. The surplus fuel (return fuel) from each fuel injection nozzle 6 is guided to a common return passage 10 by each return passage 10 and returned to the fuel tank 3 by this return passage 10.

  In addition, a pressure control valve 11 is provided in the high-pressure pump 4 to control the fuel pressure (common rail pressure) in the common rail 1. The pressure control valve 11 is connected to the fuel tank 3 from the high-pressure pump 4 by a duty signal from the ECU 100. The flow area of the return passage 10 for surplus fuel to the fuel is adjusted, whereby the amount of fuel discharged to the common rail 1 side can be adjusted to control the common rail pressure.

  Specifically, the target common rail pressure is set according to the engine operating conditions, and the common rail pressure is feedback-controlled through the pressure control valve 11 so that the common rail pressure detected by the rail pressure sensor 2 matches the target common rail pressure. It is configured.

  As shown in FIG. 2, the ECU 100 of the diesel engine E having the common rail 1 in the work vehicle (agricultural work machine) has three types of modes, a travel mode A, a normal work mode B, and a heavy work mode C in relation to the rotational speed and the output torque. The configuration has a control mode.

  The traveling mode A is droop control in which the output also varies with the variation of the engine speed. It is used when traveling without farming. For example, when the traveling speed is reduced or stopped by applying a brake, the engine speed decreases with an increase in the traveling load, so that the traveling speed can be safely reduced or stopped.

  The normal work mode B is isochronous control in which the engine speed is constant and the output is changed according to the load even when the load varies. It is used for normal farm work. For example, if it is a tractor, it is when the cultivated land is hard during plowing work and resistance is applied to the plowing blade, and if it is a combine, the output fluctuates to maintain the rotation speed even when the harvest is heavy and the load increases during harvesting Is the time.

  In the heavy work mode C, in addition to the isochronous control in which the engine speed is constant and the output is changed according to the load even when the load fluctuates in the same manner as the normal work mode B, the engine speed is increased when the load is close to the limit. This is a control with heavy load control that increases In particular, it is used when farming near the load limit. For example, when plowing with a tractor, the engine output increases beyond the normal limit even when encountering hard cultivated land, so work can be performed efficiently without interruption. .

  These work modes A, B, and C are operations of a work mode changeover switch that can switch between the work modes A, B, and C, or a shift operation of a traveling speed change lever of a farm vehicle (tractor, combine, rice transplanter, etc.) Alternatively, it is configured to be switched by an on / off operation or the like of a work clutch (rotary if it is a tractor, and mowing part or threshing part if it is a combine).

  In diesel engine E, pilot injection that injects a small amount of fuel in a pulse manner prior to main injection makes it possible to shorten the ignition delay, reduce the knocking noise peculiar to diesel engine E, and reduce noise It has a simple structure.

  This pilot injection is performed only once or twice before the main injection. By using the accumulator fuel injection device of the common rail 1, pilot injection is performed according to the situation of the engine E. Thus, it becomes possible to reduce the noise and the generation of white smoke or black smoke due to incomplete combustion. Further, by performing pilot injection in which a small amount of fuel is pulse-injected prior to main injection, the amount of nitrogen oxides in the exhaust gas is reduced.

  FIG. 3 shows a side view of a tractor equipped with a diesel engine having the common rail 1 as described above, and FIG. 4 shows a plan view thereof. In the plan view, the cabin 14 shown in FIG. 3 is omitted.

  The tractor includes front wheels 12 and 12 and rear wheels 13 and 13 at the front and rear portions of the fuselage, and the rotational power of the engine E mounted on the front portion of the fuselage is appropriately decelerated by a transmission in the transmission case T so that the front wheels 12 , 12 and the rear wheels 13, 13.

  A steering handle 16 is supported on the handle post 15 in the cabin 14 at the center of the body, and a seat 17 is provided behind the steering handle 16. A forward / reverse lever 18 is provided below the steering handle 16 to switch the advancing direction of the aircraft to the front / rear direction. When the forward / reverse lever 18 is moved to the front side, the aircraft moves forward, and when it is moved backward, the aircraft moves backward.

  An accelerator lever 25 for adjusting the engine speed is provided on the opposite side of the forward / reverse lever 18 with the handle post 15 in between, and an accelerator for similarly adjusting the engine speed is provided at the right corner of the step floor 19. The pedal 23 and left and right brake pedals 24L, 24R for operating the left and right rear wheels 13, 13 are provided. A clutch pedal 20 is provided at the left corner of the step floor 19.

  The main transmission lever 26 is located at the left front portion of the seat 17, the auxiliary transmission lever 27 capable of selecting any of the low speed, medium speed, high speed and neutral positions is located behind the main transmission lever 26, and further on the right side thereof is the PTO transmission lever 28. Is provided. Further, on the right side of the seat 17, a position lever 29 for setting the height of the working machine 21 (rotary or the like), an automatic tilling lever 30 for automatically setting the tilling depth of the field, and the working machine 21 after these levers. The right-up switch 31 and the right-down switch 32 are arranged, and then the automatic horizontal switch 33 and the backup switch 34 of the work machine 21 are arranged. The backup switch 34 automatically raises the work machine 21 when the machine moves backward. The work machine 21 has a configuration in which a link 22 is connected to the rear of the machine body. The tractor performs work such as tillage in the field by driving the work machine 21 and running the machine body. 21a is a hydraulic cylinder which raises and lowers the working machine 21.

  FIG. 5 is a schematic diagram of intake and exhaust into the cylinder 5 of the engine, which is an embodiment of a four-cycle diesel engine. The air supercharged by the intake turbine 36 of the supercharger TB passes through the intake turbine 36 and the intercooler 37 from the air cleaner 35 and is sent from the intake manifold 38 into the cylinder 5. Reference numeral 39 is an intake valve, and 40 is a piston. A cam 48 opens and closes the intake and exhaust valves 39 and 41 via a rocker arm 49.

The exhaust gas combusted in the cylinder 5 passes through the exhaust manifold 42 from the exhaust valve 41 and is then discharged by driving the supercharger TB with the exhaust turbine 45 of the supercharger TB.
The diesel engine has an EGR (exhaust gas recirculation device) circuit 44 for mixing a part of the exhaust gas into the intake side. In the EGR circuit, a part of the exhaust gas is mixed into the intake side to reduce the amount of oxygen (O2), thereby reducing the generation of nitrogen oxide Nox. However, if the EGR rate increases too much, the amount of oxygen decreases and incomplete combustion occurs. Therefore, it is necessary to adjust the EGR rate according to the combustion state. This adjustment is performed by the EGR valve 43. The EGR circuit 44 connects between an exhaust pipe 55 on the downstream side of a post-processing device 46 described later and an intake pipe 56 on the upstream side of the intake turbine 36 of the supercharger TB. In addition, an EGR cooler 57 is provided in the middle of the EGR circuit 44. The amount of exhaust gas reduced into the cylinder 5 varies depending on how the EGR valve 43 is opened and closed.

  The exhaust gas that has passed through the exhaust turbine 45 passes through the aftertreatment device 46 and is discharged from the muffler 50 into the atmosphere. The post-processing device 46 includes an oxidation catalyst (DOC) 46a and a diesel particulate filter (DPF) 46b.

  The oxidation catalyst (DOC) burns the incombustible chamber, and the diesel particulate filter (DPF) is for collecting the particulate matter (PM). The EGR valve 43 and the throttle valve 47 are controlled by the ECU 100. The post-processing device 46 may be composed of only a diesel particulate filter (DPF) 46b. If an oxidation catalyst (DOC) is provided, the non-combustible material burns, resulting in cleaner exhaust gas.

  When the state of the exhaust gas is low (low load) continues for a long time, the DPF 46b has a concern that PM will accumulate and the capacity may be reduced. Therefore, a throttle valve 47 is provided on the lower side of the post-processing device 46, and when the throttle valve 47 is throttled, the pressure in the DPF 46b is kept high, so the temperature also rises. This makes it possible to regenerate the DPF 46b due to the influence of a high temperature. That is, when exhaust gas having a high temperature passes through the DPF 46b, the DPF 46b is regenerated by burning off the PM present in the DPF 46b.

  In the DPF regeneration operation for regenerating the DPF 46b, both the EGR valve 43 and the throttle valve 47 are throttled. Then, the gas temperature in the DPF 46b is raised together with the retard (retard) of the fuel injection timing so that the DPF 46b starts to be regenerated. This eliminates the need for fuel after-injection (in order to increase the exhaust gas temperature) or reduces the number of after-injections, so that the amount of fuel consumption can be suppressed and the environment is good.

  As a condition for performing such a DPF regeneration operation, the pressure sensor 52 is provided on the upper side of the post-processing device 46, the pressure sensor 53 is provided on the lower side of the post-processing device 46, and this pressure difference is a predetermined value or more. Then, since PM accumulates in the DPF 46b and becomes a resistance, the DPF regeneration operation is performed. Moreover, it is good also as a structure which provides the pressure sensor 58 between DOC46a and DPF46b instead of the pressure sensor 52. FIG.

  Further, if the state in which the DPF regeneration operation is started continues for a long time, the DPF 46b is damaged due to an overheating state. Therefore, a temperature sensor 59 is provided on the lower side of the post-processing device 46, and when the value of the temperature sensor 59 exceeds a predetermined value, the DPF regeneration operation is stopped and the normal operation is resumed.

  In normal operation, the EGR valve 43 and the throttle valve 47 are simultaneously controlled to appropriately control the EGR amount. In particular, by having the throttle valve 47, the gas temperature in the DPF 46b can be kept high.

  With the configuration as described above, an intake throttle is not required. In other words, since the intake side pressure is high in an engine with a supercharger, an exhaust throttle valve or an intake throttle is required to secure the amount of EGR gas, and control in conjunction with the EGR valve is required, but such a system is unnecessary. It becomes.

  Further, since the exhaust gas downstream of the DPF 46b is taken out, it is possible to prevent the performance deterioration caused by the dirt of the supercharger TB. And since EGR gas is cooled by the EGR cooler 57, an effect becomes large with respect to NOx reduction.

  As described above, in the DPF forced regeneration mode in which the regeneration operation of the DPF is performed, the exhaust throttle valve 47 is throttled and the EGR valve 43 is fully closed by ON-OFF control. Therefore, NO is increased because the exhaust gas is not reduced, and this NO is converted to NO2 by the oxidation catalyst (DOC) 46a, and regeneration of the DPF 46b is promoted.

  Further, when the engine rotation shifts to low idle during the forced regeneration of the DPF 46b, the EGR valve 43 is fully opened. Since the temperature sensor 59 is provided on the downstream side of the DPF 46b, it may be added to the condition that the detection value by the temperature sensor 59 has risen to a predetermined value or more.

  When the DPF 46b is forcibly regenerated by restricting the throttle valve 47, the engine speed is reduced to increase the supply oxygen amount, and the exhaust gas flow rate is decreased to increase the temperature easily. However, when the engine speed is changed to low idle or in the vicinity thereof during regeneration, soot burns rapidly due to an increase in the amount of supplied oxygen and a decrease in the flow velocity. As a result, the temperature may rise rapidly and the DPF 46b may be damaged. Therefore, it is necessary to manage the soot that the maximum temperature does not exceed the allowable temperature.

  For this reason, when the temperature sensor 59 exceeds a predetermined value, the engine speed is increased to a medium speed range. Accordingly, the flow rate of the exhaust gas is increased, so that the maximum temperature is lowered and the DPF 46b can be prevented from being damaged. Further, when the predetermined value of the temperature sensor 59 is controlled in the vicinity of the limit value, the DPF 46b can be efficiently regenerated.

  In order to increase the engine speed to the middle speed range, it may be configured to once increase to the maximum speed and then decelerate to the middle speed range, so that the exhaust gas once flows at the maximum speed. For example, it is possible to prevent the DPF 46b from being heated and exceeding the threshold temperature.

  Further, during the forced regeneration of the DPF 46b, when the engine speed is shifted to low idle as described above, the post-injection is interrupted, and then the engine speed is increased to the maximum speed and shifted to the medium speed range. Then, post-injection is resumed. Thereby, since the rapid rise in the exhaust gas temperature can be suppressed, damage to the DPF 46b can be prevented.

  When the differential pressure across the DPF 46b exceeds a predetermined value, the driver selects the regeneration mode of the DPF 46b after the operation with the selection switch 67, so that the DPF 46b is automatically regenerated. After the DPF 46b is regenerated, the engine is automatically stopped. To be configured. The differential pressure across the DPF 46b is monitored by pressure sensors 58 and 53. If the differential pressure across the DPF 46b immediately before the engine stops is equal to or greater than a predetermined value, a warning lamp or alarm notifies the driver, and the driver operates a switch (not shown) for regenerating the DPF 46b.

  Even when the engine key is in the cut position, since the regeneration mode is selected, the engine keeps rotating in the idling state and performs regeneration of the DPF 46b. When the differential pressure before and after the DPF 46b falls below a predetermined value, the engine is automatically stopped.

Thus, even after the work is completed, the DPF 46b can be automatically regenerated and the engine can be stopped, so that the driver can leave the machine and perform other work.
When the DPF 46b is regenerated, the intake side air may be sent from the pipe 61 to the upstream side of the DPF 46b as shown in FIG. That is, when the DPF 46b is regenerated, the valve 60 may be opened so that the intake air on the upstream side of the turbocharger TB having a large amount of oxygen is sent to the upstream side of the DPF 46b. Thereby, the reproduction efficiency is improved.

  Alternatively, the temperature of the DPF 46b may be monitored by the temperature sensors 62 and 59, and the temperature increase during regeneration may be confirmed in three steps. First, the intake is throttled (not shown), and the temperature rise in the throttled state of intake is confirmed. Next, the first post injection is performed to check the temperature rise. At this time, if the temperature before and after the DPF 46b does not reach 250 degrees, further temperature rise cannot be expected even if the second post-injection is performed. Therefore, the regeneration is temporarily interrupted. Of course, if it is 250 degrees or more, the second post injection is performed to regenerate the DPF 46b.

  As shown in FIG. 5, an air-fuel ratio sensor 63 is provided on the downstream side of the DPF 46b. When the post-injection is performed to regenerate the DPF 46b, if the fuel injection amount is too large, the fuel consumption is deteriorated. If the fuel injection amount is small, the temperature does not increase and the regeneration cannot be performed. Therefore, the injection amount is determined by feeding back the value of the air-fuel ratio sensor 63 to the ECU 100. As a result, the fuel consumption becomes appropriate and the DPF 46b can be regenerated. Further, instead of the air-fuel ratio sensor 63, a pressure value in the intake manifold may be fed back.

  When regenerating the DPF 46b as described above, in the case of a plurality of cylinders, the combustion of some cylinders may be stopped. Thus, by stopping the combustion of some cylinders, the exhaust temperature may be increased by increasing the load per cylinder even if the engine friction is the same.

  The flowchart shown in FIG. 6 shows a coping method when automatic reproduction fails. When the amount of PM in the DPF 46b exceeds the predetermined amount P, automatic regeneration is started. However, the exhaust temperature does not rise depending on the work situation, and automatic regeneration may not be possible. In such a case, the automatic regeneration is continued and tried again. However, if automatic regeneration is not possible even if the automatic regeneration is tried a plurality of times (for example, 5 times), the ECU 100 permits the manual regeneration. . And it is set as the structure which displays the permission content of manual reproduction | regeneration on the liquid crystal display part 68 of a driving | operation part. At this time, it may be notified by voice.

  When manual regeneration is not executed for a predetermined time Q after the display for prompting manual regeneration is displayed on the liquid crystal display unit 68 of the operation unit, the ECU 100 is configured to output a signal for performing automatic regeneration again, and similarly, automatic regeneration cannot be performed. In some cases, the automatic regeneration is continued and tried again. However, if automatic regeneration is not possible even if automatic regeneration is attempted a plurality of times (for example, 5 times), the ECU 100 permits the manual regeneration. This cycle is repeated, but when the amount of PM in the DPF 46b approaches the limit value, the driving is forcibly stopped and manual regeneration is promoted. To forcibly stop traveling, the traveling hydraulic clutch in the transmission case is disengaged.

  When the manual regeneration is completed, the PM amount in the DPF 46b can be calculated by calculating the PM amount theoretical value V1. Although there are various methods for calculating the PM amount theoretical value V1, the details thereof will be omitted, but basically, the PM amount to be removed is estimated from the exhaust gas temperature during regeneration and the regeneration time. The estimated amount to be removed is slightly different from the type and size of the DPF and the internal structure, but is not so problematic.

  Further, when the manual regeneration is completed, an actual measurement value V2 of the PM amount in the DPF 46b is obtained. In the embodiment, the PM amount actual measurement value V2 in the DPF 46b is obtained from the differential pressure between the upstream pressure sensor 58 and the downstream pressure sensor 53 of the DPF 46b.

In the relationship between the PM amount theoretical value V1 and the PM amount actual measurement value V2,
PM amount theoretical value V1 <PM amount actual measurement value V2
When the above is established, the manual regeneration is continued again. “◯ kPa” described in the flowchart of FIG. 7 is a theoretical value of the PM amount in the DPF 46b when the manual regeneration at that time is completed, and indicates the PM amount theoretical value V1.

When manual regeneration is complete, manual regeneration is complete.
PM amount theoretical value V1> PM amount actual measurement value V2
When is established.

  As a result, the PM amount actual measurement value V2 is always smaller than the theoretical PM amount V1 obtained by the calculation when the manual regeneration is completed, so that it is possible to prevent the PM amount in the DPF 46b from being excessively accumulated.

  When manual regeneration cannot be continued due to work circumstances, the regeneration can be terminated by turning on the forced end switch 69. In this case, since the operator can recognize by continuing the display on the liquid crystal display unit 68 of the driving unit, manual regeneration can be quickly performed between work periods.

  An agricultural machine such as a tractor may not work for a long time in the off-season. Therefore, manual regeneration may be performed using this period so that the PM accumulation in the DPF 46b is made substantially zero. However, in the long-time operation of manual regeneration, there is a problem of exhaust heat and oil dilution (fuel leakage into the oil pan), so that only a dealer's serviceman can perform. Manual regeneration is possible for a long time (about 45 minutes) by an instruction from a service tool or the like that can be used only by service personnel. Since 45 minutes is the case of the average size DPF mounted on the tractor, it may be changed as appropriate for small and large sizes. When manual regeneration is performed for a long time, the PM accumulation amount in the DPF 46b becomes substantially zero. Therefore, the PM amount theoretical value V1 obtained by calculation at this time is forcibly reset to zero. In this way, since there is no deviation from the calculated value, it is possible to prevent PM from being excessively deposited in the actual DPF.

  In addition, as described above, when manual regeneration is performed for a long time, the display for prompting the oil change is displayed on the liquid crystal display of the operation unit in consideration of the effect of oil dilution (fuel leakage into the oil pan). The display is made on the unit 68. The series of configurations described above is shown in the flowchart of FIG.

  As shown in FIG. 9, a generator 70 is mounted on the engine, and the generator 70 is driven by a belt 71. The ECU 100 controls on / off of the generator 70. Then, power generation is not performed when the PM accumulation amount in the DPF 46b is small, and power generation is performed when the PM accumulation amount in the DPF 46b is large. As a result, when the load acts on the engine, the exhaust temperature rises and PM in the DPF 46b is removed. Accordingly, the interval between automatic regenerations can be increased, and fuel consumption associated with regeneration can be suppressed, and the influence of oil dilution (fuel leakage into the oil pan) can be reduced.

  In FIG. 10, a pressure sensor 74 is provided in the exhaust manifold 72 and a pressure sensor 75 is provided in the intake manifold 73. The ECU 100 measures the differential pressure of the pressure sensor 74 on the exhaust side and the pressure sensor 75 on the intake side. The turbo lag of the supercharger TB during transient operation is measured from the value of the exhaust side pressure sensor 74 and the differential pressure of the intake side pressure sensor 75, and the intake air amount is measured by the air flow sensor 76. Thus, the change in the intake air amount due to the turbo lag is grasped and used as a correction factor for PM amount calculation (estimated reduction in excess air ratio). Used for both acceleration and deceleration. As a result, the PM emission amount during the transient operation can be estimated to some extent.

  During regeneration of the DPF 46b, it is necessary to raise the exhaust gas temperature. As this method, as shown in FIG. 11, the amount of cooling water flowing in the radiator 77 is reduced under the control of the ECU 100. Specifically, the electromagnetic valve 78 is closed to cut the amount of cooling water flowing into the radiator 77 by 1/3. As a result, a load is also applied to the cooling water pump, and the exhaust temperature rises during regeneration of the DPF 46b, so that regeneration can be performed efficiently. However, when the temperature of the cooling water rises excessively and becomes overheated, the electromagnetic valve 78 needs to be opened.

  On the other hand, in the automatic regeneration performed while traveling (work, on the road), the following problems occur. The calculated value (estimated from the engine operating time, fuel injection amount, and exhaust gas temperature or the memorized value by the experiment in the average use situation) used in the determination of the PM accumulation amount in the DPF 46b is an actual value. Deviation often occurs with respect to the amount of accumulated PM. Even memorized experimental values will be shifted depending on the engine usage. This deviation tends to increase each time reproduction is repeated.

  Accordingly, the PM amount threshold (α) in the DPF 46b for automatic regeneration is increased by a predetermined amount (δ) once every several times (for example, about 5 times). From the next time, when the amount of PM in the DPF 46b becomes (α + δ), the automatic regeneration is entered, so that the operation time until the automatic regeneration is entered becomes longer. Thus, by periodically correcting the PM amount threshold value in the DPF 46b, the regeneration time can be extended, and oil dilution (fuel leakage into the oil pan) associated with regeneration can be suppressed. This makes it possible to lengthen the interval between oil changes. In addition, fuel consumption accompanying regeneration can be suppressed.

12 (a) and 12 (b) show the configuration when the DPF 46b is mounted on the tractor.
The periphery of the DPF 46 b is configured to be covered with a duct 79. The air intake port 80 to the duct 79 is positioned in front of the airframe, and is configured to take in air sent from the radiator fan 81.

  A plurality of fins 82 are provided in the duct 79, and the air in the duct 79 is agitated by the fins 82 so that the air flow in the duct 79 is not biased. It is configured to be uniform (FIG. 12C). The air taken into the duct 79 passes through the DPF 46b and is discharged to the rear of the aircraft. Thereby, it can prevent that the inside of an engine room becomes high temperature with the heat of DPF46b, and can protect the equipment in an engine room. Further, since the DPF 46b is covered with the duct 79, it is possible to prevent dust such as waste straw from accumulating on the DPF 46b and igniting the dust.

  When regenerating the DPF 46b, as shown in FIG. 12D, the fins 82 are closed to prevent air from entering the duct 79 so that the DPF 46b is not cooled too much. However, when the temperature of the DPF 46b becomes excessively high, the fin 82 is opened to some extent to generate an air flow. The fin 82 is rotated by the motor 83 and controlled by the ECU 100.

  FIG. 13 shows the relationship between the working hydraulic pressure of the work implement and the fuel injection amount. The horizontal axis is the flow of time. When the hydraulic pressure of a work machine (rotary or the like) attached to the tractor is operating, the fuel injection amount is increased according to the hydraulic pressure. The increase in the fuel injection amount is up to a predetermined threshold value. Line L1 indicates a change in work implement hydraulic pressure, and line L2 indicates an increase in fuel injection amount. Line L3 is a threshold value of the fuel injection amount.

  As a result, by increasing the fuel injection amount in accordance with the increase in the hydraulic pressure of the work implement, it is possible to prevent a decrease in the engine speed and an engine stall and to continue the work comfortably.

  It can be used for farm vehicles such as tractors and combiners as well as general vehicles.

PM Granulated material 46b Diesel particulate filter (DPF)
68 Liquid crystal display unit 100 ECU

Claims (3)

  In a work vehicle equipped with a diesel engine equipped with a DPF (46b) that collects particulate matter (PM) in exhaust gas, if the amount of PM deposited in the DPF (46b) exceeds a predetermined amount (P), the ECU (100) is configured to output a signal for performing automatic regeneration of the DPF (46b). When this automatic regeneration cannot be executed, the automatic regeneration execution is continuously output and the automatic regeneration execution output is automatically performed a plurality of times. An ECU (100) configured to output a signal for performing manual regeneration when regeneration cannot be started.   2. The work vehicle according to claim 1, wherein the content of the manual regeneration output output from the ECU (100) is displayed on the liquid crystal display unit (68) of the driving unit. 3.   When manual regeneration is not executed for a predetermined time (Q) after the display for prompting manual regeneration on the liquid crystal display unit (68), the ECU (100) outputs a signal for performing automatic regeneration again. The work vehicle according to claim 2.

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