JP2013011256A - Tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase efficiency in regenerating a diesel particulate filter arranged in an exhaust passage of exhaust gas.SOLUTION: This tractor is mounted with a diesel engine E having the diesel particulate filter 46b for collecting particulate matter PM in the exhaust gas. A constitution of the tractor is characterized by constituting so as to drive a hydraulic system 68 for a working machine for driving the working machine installed in the tractor when regenerating the diesel particulate filter 46b. The constitution of the tractor is characterized by constituting so as to cool oil of the hydraulic system 68 for the working machine by an oil cooler 69 when regenerating the diesel particulate filter 46b by driving the hydraulic system 68 for the working machine.

Description

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

  In regenerating the diesel particulate filter (DPF), exhaust gas temperature raising means (heater) is provided on the upstream side of the DPF (for example, see Patent Document 1).

JP 2007-132306 A

  The above-described technique, that is, a configuration in which only a heater is provided on the upstream side of the DPF has a drawback that the exhaust gas temperature cannot be quickly raised. Furthermore, it takes time to raise the temperature at a low temperature.

  The subject of this invention is providing the tractor 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 tractor equipped with a diesel engine (E) equipped with a diesel particulate filter (46b) that collects particulate matter (PM) in exhaust gas, a diesel particulate filter ( 46b) is a tractor characterized by being configured to drive a working machine hydraulic system (68) that drives a working machine to be mounted on the tractor.

  According to the first aspect, when the diesel particulate filter (46b) is regenerated, a load is applied to the engine by driving the working machine hydraulic system (68), and the exhaust temperature quickly rises due to this load.

  According to the second aspect of the present invention, when the working machine hydraulic system (68) is driven to regenerate the diesel particulate filter (46b), oil in the working machine hydraulic system (68) is supplied to an oil cooler (69). The tractor according to claim 1, wherein the tractor is cooled in step).

According to the second aspect of the present invention, the oil can be protected by cooling the oil of the hydraulic system for work implement (68) with the oil cooler (69).
According to the third aspect of the present invention, a heater (72) is provided in the intake system to the cylinder chamber (5) of the diesel engine (E), and the heater (72) is energized during regeneration of the diesel particulate filter (46b). The tractor according to claim 1 or 2, wherein the intake air temperature is increased.

In claim 3, the exhaust gas temperature rises by energizing the heater (72) of the intake system to raise the intake air temperature.
In the invention according to claim 4, a heater (73) is provided in the exhaust system upstream of the diesel particulate filter (46b), and when the diesel particulate filter (46b) is regenerated, the heater (73) is energized to exhaust the exhaust temperature. The tractor according to claim 1, wherein the tractor is configured to rise.

  According to the fourth aspect of the present invention, the exhaust gas temperature is raised by energizing the heater (73) of the exhaust system.

  Since the present invention is configured as described above, according to the first aspect of the present invention, the exhaust gas temperature rapidly rises during regeneration of the diesel particulate filter (46b), so that it can be efficiently regenerated in a short time.

According to the second aspect of the present invention, it is possible to protect the oil of the working machine hydraulic system (68) that is driven when the diesel particulate filter (46b) is regenerated.
In Claims 3 and 4, the exhaust gas temperature rises quickly, and the diesel particulate filter (46b) can be efficiently regenerated.

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 Schematic diagram of intake and exhaust systems Schematic diagram of intake and exhaust systems Schematic diagram of intake and exhaust systems Exhaust gas temperature rise time chart Mission oil system diagram Schematic diagram of part of the exhaust system Cross section of DPF outlet Side and front view of DPF assembly plate

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. 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 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.

FIG. 6 shows a construction in which a working machine hydraulic system 68 for driving a working machine mounted on the tractor is added to FIG.
In contrast to the automatic regeneration in which the DPF 46b is regenerated while the vehicle is running, regeneration that is performed with the vehicle body stopped is called forced regeneration (manual regeneration). This is a case where the number of deposits is not acceptable. During such forced regeneration, it is necessary to quickly raise the exhaust gas temperature. Therefore, a working machine hydraulic system 68 that drives the working machine of the tractor is used.

  When the DPF 46b is forcibly regenerated, the working machine hydraulic system 68 is driven to apply a load to the engine. When a load is applied to the engine, the exhaust gas temperature rises quickly, so that the forced regeneration time can be shortened.

  In addition, since the oil cooler 69 for cooling the oil of the working machine hydraulic system 68 is provided, the oil can be protected. The cooling fan 70 of the engine radiator 75 is driven by an electric motor 71. Even when the engine is at idling speed during forced regeneration of the DPF 46b, high rotation can be obtained by passing a high current through the electric motor 71. It becomes possible. In order to obtain a high current, a load is applied to the generator, and the exhaust gas temperature quickly rises even with this load.

  Further, although the heater 72 is provided in the intake system for improving engine startability at low temperatures, the intake air temperature is raised by energizing the heater 72 even during the forced regeneration of the DPF 46b. As a result, the exhaust gas temperature rises quickly. Further, since a load is applied to the generator in order to energize the heater 72, the exhaust gas temperature quickly rises even with this load.

  Further, a heater 73 may be provided on the upstream side of the DPF 46b, and the exhaust gas temperature may be directly increased by the heater 73. Even when the heater 73 is driven, a load is applied to the generator to energize the heater 73, so that the exhaust gas temperature quickly rises even at this load.

  The oil cooler 69 described with reference to FIG. 6 is an air-cooling type using the wind of the radiator fan 70, but FIG. 7 illustrates a water-cooling type configuration. In this case, the cooling fan 76 of the radiator 75 may be driven by an electric motor or may be configured to be driven by the driving force of the engine.

  Cooling water for cooling the engine flows in the radiator 75. Since the cooling water after flowing in the engine has a high temperature, the cooling water is sent to the radiator 75 and the temperature is lowered by the cooling fan 76. The cooling water whose temperature has been lowered flows again to the engine, but a part of the cooling water is configured to be sent to the oil cooler 74. Since oil flows from the working machine hydraulic system 68 to the oil cooler 74, heat is exchanged between the cooling water and the oil here to cool the oil. When the DPF 46b is regenerated, the working machine hydraulic system 68 is driven as described above, but the oil can be efficiently cooled using the cooling water.

  FIG. 8 shows another configuration of the configuration shown in FIG. The oil cooler 74 is attached to a cylinder block of the engine. This makes it possible to cool the oil efficiently without changing the basic configuration.

  Oil that is shared with or separate from the working machine hydraulic system 68 is contained in the transmission case T of the tractor. Some of the gears in the transmission case T may rotate even when the engine is idling, and some may not. When the DPF 46b is regenerated, if the oil temperature in the transmission case T is high (oil viscosity: low), no resistance is applied to the rotating gear. That is, since the load applied to the engine is reduced, the exhaust gas temperature rises slowly. Therefore, when the oil temperature in the transmission case T is high, the engine speed during regeneration of the DPF 46b is configured (automatically) to be higher than the idling speed. Thereby, exhaust gas temperature rises rapidly.

  Further, when the oil temperature in the transmission case T is lower than a predetermined value (oil viscosity: high), sufficient resistance is applied to the rotating gear, so that the engine speed during regeneration of the DPF 46b is lower than the idling speed. Configure (automatically) to be Thereby, the amount of fuel used can be suppressed. FIG. 9 specifically shows changes in engine speed, engine load, and exhaust gas temperature during regeneration of the DPF 46b, depending on the oil temperature (high, medium, and low) in the transmission case T.

  FIG. 10 is a system diagram of transmission oil. An oil tank 77 for temporarily storing the oil in the transmission case T is provided. The oil temperature is detected by the mission temperature sensor 80 after the engine is started, and when this value is lower than a predetermined value, the oil pump 78 is driven and a part of the oil is temporarily stored in the oil tank 77. At this time, it is necessary to carry out within a range that does not affect the gear or the like.

  Since the amount of oil in the transmission case T has decreased, the oil temperature rises faster. A thermostat 79 is provided at the end of the return circuit from the oil tank 77 into the transmission case T. When the oil temperature in the transmission case T rises, the thermostat 79 opens and the oil in the oil tank 77 is transferred to the transmission case. It is assumed that the configuration returns to T.

  Such a configuration is suitable for improving the warm-up performance in cold districts regardless of the manual regeneration of the DPF. The work performance can be secured by improving the warm-up performance. Further, the oil in the oil tank 77 gradually returns when the thermostat 79 is opened and closed, so that an appropriate oil temperature is obtained.

  FIG. 11 shows a configuration in which an exhaust valve 81 is provided in the exhaust pipe 55 on the downstream side of the DPF 46b. The ECU 100 is configured to input information on the accelerator opening, the vehicle speed, and the shift position (gear position) and control the exhaust valve 81 based on the information. By changing the exhaust valve opening according to the accelerator opening during vehicle travel, the temperature of the exhaust gas flowing into the DPF 46b is suppressed, and the temperature is maintained when DPF regeneration is performed during travel. Thereby, the change of the exhaust gas temperature which flows into DPF46b can be made small, and the reproducible temperature of DPF46b can be maintained. The pressure sensor 53 monitors whether there is a sudden pressure change.

  FIG. 12 shows a configuration in which the tail pipe 82 is connected to the downstream side of the DPF 46b. However, at the inlet portion P of the tail pipe 82, a resonance noise is generated due to pressure fluctuation. Therefore, a case 83 is formed on the outer periphery of the DPF 46b to form a space 84, and the space 84 and the inlet P are connected by a connecting passage 84a. As a result, the pressure fluctuation at the inlet P is reduced, and the resonance noise is also reduced.

  FIG. 13 shows an assembly plate 85 when the post-processing device 46 is mounted on the engine. FIG. 13A is a view of the engine as viewed from the side, and FIG. 13B is a view of the engine as viewed from the back. The assembly plate 85 is composed of a plate 85a, a plate 85b, and a plate 85c (welding or the like). The plate 85a is fixed to the rear plate of the engine E with bolts, and the plate 85b is fixed to the cylinder head with bolts. . The plate 85c has a through hole for a bolt, and the DPF 46b main body is fixed through the bolt through the flange portion F of the DPF 46b. Thereby, a heavy DPF can be firmly fixed.

  Each of the above-described embodiments is illustrated or described separately or mixed for easy understanding, but 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.

PM Granulated material E Diesel engine 5 Cylinder chamber 46b Diesel particulate filter (DPF)
68 Hydraulic System for Work Equipment 69 Oil Cooler 72 Intake System Heater 73 Exhaust System Heater

Claims (4)

  In a tractor equipped with a diesel engine (E) equipped with a diesel particulate filter (46b) that collects particulate matter (PM) in the exhaust gas, the operation of mounting the tractor on the regeneration of the diesel particulate filter (46b) A tractor configured to drive a working machine hydraulic system (68) for driving the machine.   When the working machine hydraulic system (68) is driven to regenerate the diesel particulate filter (46b), the oil in the working machine hydraulic system (68) is cooled by the oil cooler (69). The tractor according to claim 1.   A heater (72) is provided in the intake system to the cylinder chamber (5) of the diesel engine (E), and when the diesel particulate filter (46b) is regenerated, the heater (72) is energized to increase the intake air temperature. The tractor according to claim 1, wherein the tractor is configured.   A heater (73) is provided in the exhaust system upstream of the diesel particulate filter (46b), and when the diesel particulate filter (46b) is regenerated, the heater (73) is energized to increase the exhaust temperature. The tractor according to claim 1, wherein:

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