JP2012137042A - Working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that when outside air temperature is extremely low, regeneration of a DPF (Diesel Particulate Filter) fails because the temperature of the DPF itself decreases regardless of stopping driving of a fan affecting the DPF.SOLUTION: A working vehicle mounts a diesel engine E and a diesel particulate filter 46b that captures a particulate matter PM in exhaust gas, and is configured to control regeneration for removing the particulate matter PM in the diesel particulate filter 46b. The vehicle includes an outside air temperature sensor 70 detecting outside air temperature, and determines an engine speed during controlling regeneration of the diesel particulate filter 46b in accordance with a detection value of the outside air temperature sensor 70. The vehicle is configured to increase an engine speed under the condition of a lower outside air temperature than an engine speed under the condition of a higher outside temperature indicated by detection values of the outside air temperature sensor 70 based on a predetermined threshold M.

Description

  The present invention relates to a work vehicle equipped with a diesel engine equipped with a diesel particulate filter (DPF) for removing particulate matter (PM) in an exhaust system.

  When granulated material (PM) accumulates inside the DPF, it is necessary to remove (regenerate) by raising the exhaust gas temperature. However, if the temperature of the DPF itself is low, regeneration is not performed efficiently and regeneration is poor. Therefore, the vehicle is provided with an outside air temperature sensor, and when the outside air temperature detected by the outside air temperature sensor is equal to or lower than a predetermined temperature, the fan that affects the temperature drop of the DPF is not operated. Thus, when the outside air temperature is low, the wind generated by the fan is prevented from hitting the DPF, and the temperature of the DPF itself is prevented from lowering and the DPF is regenerated favorably (for example, Patent Document 1). reference.).

JP 2008-157099 A

  In the known technique, when the outside air temperature is low, the fan (capacitor) that affects the DPF is not driven, so that the temperature of the DPF itself does not decrease excessively and the regeneration failure of the DPF is prevented. is there.

However, when the outside air temperature is extremely low, the temperature of the DPF itself is lowered even if the driving of the fan is stopped, and a regeneration failure of the DPF occurs.
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, in the invention according to claim 1, the diesel particulate filter (46b) and the diesel engine (E) for collecting the particulate matter (PM) in the exhaust gas are mounted, and the diesel particulate filter (46b) In a work vehicle configured to perform regeneration control to remove the particulate matter (PM), an outside air temperature sensor (70) for detecting the outside air temperature is provided, and a diesel particulate filter (in accordance with a detection value of the outside air temperature sensor (70)). 46b) is configured to determine the engine speed at the time of regeneration control, and the detected value of the outside air temperature sensor (70) is lower than the state in which the outside air temperature is high based on the preset threshold (M) Is a work vehicle characterized in that the engine speed is increased.

  The engine speed during regeneration control of the diesel particulate filter (46b) is determined according to the detected value of the outside air temperature sensor (70). Then, the engine speed is set to be higher in the state where the detected value of the outside air temperature sensor (70) is lower than the state where the outside air temperature is high with reference to the preset threshold value (M).

  According to the second aspect of the present invention, the work vehicle is provided with the humidity sensor (71), and the regeneration control of the diesel particulate filter (46b) is not executed when the detected value by the humidity sensor (71) is equal to or smaller than the predetermined value. The work vehicle according to claim 1, wherein the work vehicle is configured as described above.

When the detected value by the humidity sensor (71) is less than or equal to the predetermined value, regeneration control of the diesel particulate filter (46b) is not executed.
According to a third aspect of the present invention, a manual regeneration switch (72) for performing manual regeneration of the diesel particulate filter (46b) is provided, and when the manual regeneration switch (72) is in the on state, the engine key switch (73) is depressed. 3. The work vehicle according to claim 1, wherein the work vehicle is configured to restrain the engine stop even if it is turned off.

  When the manual regeneration switch (72) for performing manual regeneration of the diesel particulate filter (46b) is in the on state, the engine is stopped even if the engine key switch (73) is turned off.

According to a fourth aspect of the present invention, the work vehicle working vehicle according to the third aspect is provided with an emergency stop switch (73a) that enables the engine to be stopped.
In case of emergency, the engine is stopped by the emergency stop switch (73a).

  Since the present invention is configured as described above, according to the first aspect of the present invention, when the outside air temperature is low, the exhaust gas temperature rises by increasing the engine speed, thereby reducing the temperature of the DPF (46b) itself. Since it can suppress, reproduction | regeneration of DPF (46b) can be performed favorably.

  In the invention according to claim 2, in addition to the effect of claim 1, when the detection value by the humidity sensor (71) is equal to or less than the predetermined value, regeneration control of the DPF (46b) is not executed. Can prevent the risk of fire.

  In the invention of claim 3, in addition to the effect of claim 1 or 2, when the manual regeneration switch (72) for performing manual regeneration of the DPF (46b) is in the on state, the engine key switch (73) is turned off. However, since the engine is stopped, the regeneration of the DPF (46b) can be performed satisfactorily.

  In the invention of claim 4, in addition to the effect of claim 3, in the case of emergency, the engine is stopped by the emergency stop switch (73a).

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 Playback block diagram Cross section of exhaust pipe Block diagram of flywheel control Cross section of DPF Block diagram of burner combustion control (A) Cross section of DPF, (b) Cross section of conventional DPF Cross section of tractor engine room Cross section of tractor engine room

The best mode for carrying out the present invention will be described.
In addition, although each Example described later is illustrated or described separately or mixed for easy understanding, these can be combined in various ways, and can be configured according to their description order and expression. -The action and the like are not limited, and there are of course cases where a synergistic effect is produced.

  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 accumulating 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 respective 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. 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. As a result, the flow rate of the exhaust gas is increased, so that the maximum temperature is lowered and damage to the DPF 46b can be prevented. 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 supercharger 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.

  As described above, when the DPF 46b is regenerated, the engine speed during regeneration is changed according to the outside air temperature. Specifically, the engine rotational speed is configured to be higher in a state where the detected value of the outside air temperature sensor (70) is lower than the state where the outside air temperature is high with reference to a preset threshold value (M). .

  When the threshold value M is 15 degrees Celsius, the engine speed is set to about 1100 rpm in a normal temperature range exceeding 15 degrees Celsius. When the threshold value M is 0 to 15 degrees Celsius, the engine speed is set to about 1200 rpm. When the threshold value M is about 0 to -20 degrees Celsius, the engine speed is set to around 1500 rpm. When the threshold value M is −20 degrees Celsius or less, the engine speed is set to about 2000 rpm.

  When the DPF 46b is regenerated, an external load is normally required. However, if there is no external load, the exhaust temperature is insufficient during regeneration, and white smoke and irritating odors become a problem. In order to prevent such a problem, if the number of rotations is increased unnecessarily, noise will increase.

  Therefore, the engine speed during regeneration is changed according to the outside air temperature. The outside air temperature sensor 70 may be connected to the ECU 100 or may be connected to a control device (CPU) 200 on the vehicle (tractor) side. ECU 100 and CPU 200 are connected by CAN communication and exchange information. The engine speed is changed by controlling the high-pressure pump 4 and the amount of fuel sent to the fuel injection nozzle 6 based on information from the outside air temperature sensor 70 (FIG. 1).

As a result, the exhaust temperature rises at a low temperature, so that regeneration is performed without delay. Also, noise can be suppressed by suppressing the engine speed at room temperature.
Reference numeral 71 denotes a humidity sensor. However, when the detected value of the humidity sensor 71 is a predetermined value or less (about 40%), the DPF 46b is not regenerated. That is, even if there is a request for regeneration, the content related to regeneration such as post injection is not performed. In particular, in agricultural machines such as tractors and combines, it becomes easy to burn if there is soot near the exhaust system or the exhaust pipe, but it is possible to prevent such problems. In addition, when the DPF 46b is intentionally reproduced by turning on a switch or the like, the fact that the reproduction is not performed is notified by lighting a lamp or a buzzer.

Instead of the humidity sensor 71, weather data may be obtained by a communication function, and regeneration of the DPF 46b may be prohibited when the outside air is in a dry state.
A manual regeneration switch 72 and an engine key switch 73 of the DPF 46b are connected to the ECU 100 (FIG. 6). Once the manual regeneration switch 72 is turned on and the regeneration is started, the engine key switch 73 is turned off to stop the engine even if the engine is stopped. That is, even when the engine key switch 73 is in the off position, the regeneration of the DPF 46b is continued without stopping the engine. The engine is automatically stopped when the reproduction is completed.

  In this case, even if the engine key is removed from the engine key switch 73, the reproduction is continued without stopping the engine, and the engine is automatically stopped when the reproduction is completed. Further, such a state is notified by lamp lighting, buzzer or the like.

  If the engine is stopped during manual regeneration of the DPF 46b, soot is left in the DPF 46b, and abnormal combustion may occur and the DPF 46b may be melted.

  However, in the case of an emergency, it is necessary to stop the engine even during regeneration. Therefore, an emergency stop switch 73a is provided, and the engine is stopped when the emergency stop switch 73a is pressed. As a result, it becomes possible to cope with the unexpected.

  Further, during manual regeneration of the DPF 46b, the left and right turn signal lamps 74L and 74R are blinked simultaneously, and when the reproduction is completed, the blinking is stopped and the horn 75 is sounded once. Thereby, it can be recognized that the DPF 46b is being regenerated and that the regeneration has been completed.

  In order to efficiently regenerate the DPF 46b, it is necessary to raise the exhaust temperature. For this reason, it is necessary to put a load on the engine. FIG. 7 shows an example of this. A valve 76 is provided at the outlet of the exhaust pipe 55. When the manual regeneration switch 72 is turned on, the motor 77 is driven by a signal from the ECU 100, and the outlet of the exhaust pipe 55 is driven by the valve 76. It is set as the structure which blocks some. As a result, the engine load increases and the DPF 46b can be efficiently regenerated.

  Further, by lowering the working machine 21 such as a rotary and pressing it against the ground, the engine load increases for driving the hydraulic pump for operating the lifting cylinder 78, so such a method may be used.

Alternatively, the air conditioner switch 79 may be forcibly turned on to operate the air conditioner compressor and apply a load to the engine.
Moreover, as shown in FIG. 8, it is set as the structure which provides the magnetic body 82 in the flywheel part 81 of an engine. The outer periphery of the flywheel portion 81 is covered with the housing 83 and the coil 84 is provided inside the housing 83.

When the manual regeneration switch 72 is turned on, a current is passed through the coil 84 to apply reverse torque to the flywheel unit 81.
As a result, a load can be applied to the engine, so that the DPF 46b can be efficiently regenerated.

  At the time of regeneration of the DPF 46b, it is necessary to raise the temperature in the DPF 46b early. Therefore, a part of the exhaust gas that has come out of the DPF 46b is discharged into the atmosphere from the exhaust pipe 55, and a part thereof is returned to the upstream side of the DPF 46b through the valve 86 (FIG. 9). Since the temperature sensor 62 is provided in the DPF 46b, the valve 86 is controlled so that the detected value of the temperature sensor 62 becomes an optimum value.

As a result, the temperature in the DPF 46b can be raised early, and the temperature in the DPF 46b can be optimally maintained, so that regeneration can be performed efficiently and regeneration time is shortened.
As shown in FIG. 10, when the manual regeneration switch 72 is turned on, the burner 88 is ignited and a flame is emitted from the injection nozzle 89 in the DPF 46b. As a result, the temperature in the DPF 46b rises at once, so that it is possible to reduce the amount of fuel used as compared with relatively performing after-injection or post-injection. Also in this case, efficient reproduction is possible by optimizing the detection value of the temperature sensor 62 in the DPF 46b.

  FIG. 11A shows a cross-sectional view of the post-processing device 46. As described above, the upstream side is the oxidation catalyst (DOC) 46a, and the downstream side is the DPF 46b. The exhaust gas from the engine is input to the upstream side of the DOC 46a, but is input by the exhaust introduction pipe 90. In the conventional configuration of the exhaust introduction pipe 90, as shown in FIG. 11 (b), when the diameter of the outer portion of the post-processing device 46 is K2, the diameter in the post-processing device 46 is the same as K2.

  On the other hand, in FIG. 11A, when the diameter of the outer portion of the post-processing device 46 is K2, the diameter in the post-processing device 46 is K1, and K1 <K2. Thereby, since the length of the longitudinal direction of the post-processing apparatus 46 can be shortened, it becomes advantageous when mounting in vehicles, such as a tractor and a combine.

  FIG. 12 shows a configuration in which the post-processing device 46 is mounted on the tractor. It arrange | positions so that the longitudinal direction of the post-processing apparatus 46 may turn into the front-back direction of a body. In this configuration, the post-processing device 46 is mounted behind the space S between the engine E and the bonnet 91. In the case where the post-processing device 46 is mounted in such a narrow space, it is effective to make the post-processing device 46 compact. The post-processing device 46 may have both the DOC 46a and the DPF 46b, or only the DPF 46b.

  In FIG. 12, a heat shield plate 92 is provided between the engine E and the post-processing device 46. Since the DPF 46b has heat, if the fuel system is damaged and scattered in the DPF 46b, there is a possibility that it may ignite. Thus, the provision of the heat shield plate 92 can prevent the above-described problems. Further, the DPF 46b is not regenerated well when the temperature is low. In particular, there is a problem if the wind from the cooling fan 93 is constantly hit. Therefore, the heat shield plate 92 can prevent the wind from the cooling fan 93 from hitting.

  Although the bonnet is omitted in the drawing shown in FIG. 13, the post-processing device 46 is arranged in the same space S as in FIG. It arrange | positions so that the longitudinal direction of the post-processing apparatus 46 may turn into the left-right direction of a body. Also in this case, the heat shield plate 94 is provided. The exhaust pipe 55 connected to the post-processing device 46 passes below the step 95, passes through the inside of the tire cover 96, and is piped to the rear part of the machine body. While the DPF 46b is being regenerated, the exhaust gas temperature rises. However, as described above, the exhaust pipe 55 is extended to the rear of the fuselage, so that the length of the exhaust pipe 55 is increased. The gas temperature can be lowered.

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

PM Granulated material E Diesel engine
M Threshold value 46b Diesel particulate filter (DPF)
70 Outside temperature sensor 71 Humidity sensor 72 Manual regeneration switch 73 Engine key switch 73a Emergency stop switch

Claims (4)

  A diesel particulate filter (46b) that collects particulate matter (PM) in exhaust gas and a diesel engine (E) are installed, and regeneration that removes particulate matter (PM) in the diesel particulate filter (46b) is performed. In a work vehicle configured to perform control, an outside air temperature sensor (70) for detecting the outside air temperature is provided, and the engine speed at the time of regeneration control of the diesel particulate filter (46b) according to the detected value of the outside air temperature sensor (70). In which the detected value of the outside air temperature sensor (70) is lower than the state in which the outside air temperature is high with reference to the preset threshold value (M), so that the engine speed is higher. A working vehicle characterized by that.   A humidity sensor (71) is provided in the work vehicle, and when the detected value by the humidity sensor (71) is equal to or less than a predetermined value, the regeneration control of the diesel particulate filter (46b) is not executed. The work vehicle according to claim 1.   A manual regeneration switch (72) for performing manual regeneration of the diesel particulate filter (46b) is provided, and when the manual regeneration switch (72) is in the on state, the engine is stopped even if the engine key switch (73) is turned off. The work vehicle according to claim 1, wherein the work vehicle is configured as described above.   The work vehicle according to claim 3, further comprising an emergency stop switch (73a) that enables the engine to be stopped.

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