JP2012159019A - Working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently regenerate a DPF in an engine with a supercharger.SOLUTION: In the working vehicle having a constitution in which the diesel particulate filter 46b for collecting particulate matter PM in an exhaust gas and the diesel engine E are mounted to the vehicle, and which performs regeneration control for removing the particulate matter PM in the diesel particulate filter 46b, a normal exhaust passage 72 having the supercharger TB at the upstream side of the diesel particulate filter 46b is formed, an exhaust bypass passage 70 which bypasses the normal exhaust passage 72 is formed, a first valve 71 is arranged at the exhaust bypass passage 70, and the first valve 71 is opened at the regeneration of the diesel particulate filter 46b.

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, a burner combustion chamber having a fuel injection nozzle and an ignition plug is provided on the upstream side of the DPF. When the amount of PM in the DPF increases, the burner is ignited to raise the exhaust gas temperature, and the PM in the DPF is heated at a high exhaust gas temperature. It is the structure which burns away (for example, refer patent document 1).

JP-A-8-260944

  In the known technology, if a high load acts on the engine and the exhaust gas temperature becomes too high, the fuel injection nozzle for DPF regeneration may be damaged by heat from the exhaust gas. Further, since the fuel injection nozzle for regenerating the DPF is provided, it becomes expensive and a lot of fuel is consumed.

  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 particulate matter (PM), a normal exhaust path (72) having a supercharger (TB) is configured upstream of a diesel particulate filter (46b), and the normal An exhaust bypass path (70) that bypasses the exhaust path (72) is configured, a first valve (71) is provided in the exhaust bypass path (70), and when the diesel particulate filter (46b) is regenerated, the first valve (71 ) Is a work vehicle characterized by being configured to open.

  During regeneration of the diesel particulate filter (46b), the first valve (71) is opened. The exhaust gas passes through both the normal exhaust path (72) and the exhaust bypass path (70). Since the amount of exhaust gas passing through the normal exhaust path (72) with the supercharger (TB) is reduced, it is possible to prevent the exhaust gas temperature from decreasing due to the resistance of the supercharger (TB).

  The invention according to claim 2 is characterized in that a second valve (73) is provided in the normal exhaust path (72), and the second valve (73) is closed when the diesel particulate filter (46b) is regenerated. The work vehicle according to claim 1 is provided.

  The second valve (73) is closed during regeneration of the diesel particulate filter (46b). Since the exhaust gas passes only through the exhaust bypass path (70), it does not receive the resistance of the supercharger (TB). For this reason, the fall of exhaust gas temperature can be prevented further.

  In a third aspect of the present invention, a temperature sensor (74) is provided upstream of the diesel particulate filter (46b), and when the detected value of the temperature sensor (74) exceeds a predetermined value, the first valve (71) is turned on. The work vehicle according to claim 1 or 2, wherein the work vehicle is configured to be closed.

When the detected value of the temperature sensor (74) exceeds a predetermined value, the first valve (71) is closed.
In a fourth aspect of the invention, a temperature sensor (74a) is provided on the downstream side of the diesel particulate filter (46b), and when the detected value of the temperature sensor (74a) is equal to or less than a predetermined value, the first valve (71 ) Is configured so as not to be closed, and is a work vehicle according to claim 3.

  Even if the detected value of the temperature sensor (74) on the upstream side of the diesel particulate filter (46b) is not less than a predetermined value, the detected value of the temperature sensor (74a) on the downstream side of the diesel particulate filter (46b) is not more than the predetermined value. The first valve (71) does not close.

  Since the present invention is configured as described above, according to the first aspect of the present invention, since the amount of exhaust gas passing through the normal exhaust path (72) with the supercharger (TB) is reduced, the supercharger (TB) It is possible to prevent the exhaust gas temperature from decreasing due to the resistance. Thereby, regeneration of a diesel particulate filter (46b) can be carried out efficiently.

  In the second aspect of the invention, in addition to the effect of the first aspect, the second valve (73) is closed when the diesel particulate filter (46b) is regenerated. Accordingly, since the exhaust gas passes only through the exhaust bypass path (70), it does not receive the resistance of the supercharger (TB). For this reason, since the fall of exhaust gas temperature can be prevented further, regeneration of a diesel particulate filter (46b) can be performed efficiently in a short time.

  In the invention of claim 3, in addition to the effect of claim 1 or claim 2, when the detected value of the temperature sensor (74) on the upstream side of the diesel particulate filter (46b) exceeds a predetermined value, the first valve (71 ) Is closed, so that deterioration and damage of the diesel particulate filter (46b) due to abnormally high temperatures can be prevented.

  In the invention of claim 4, in addition to the effect of claim 3, the downstream of the diesel particulate filter (46b) even if the detected value of the temperature sensor (74) on the upstream side of the diesel particulate filter (46b) is not less than a predetermined value. When the detected value of the temperature sensor (74a) on the side is equal to or lower than the predetermined value, the first valve (71) is not closed, and thus it 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 exhaust system Schematic diagram of exhaust system Engine perspective view Block Diagram Flow chart of post injection and exhaust temperature Flow chart of heater, post injection and exhaust temperature Schematic diagram of exhaust system Perspective view of DPF support Perspective view of engine and DPF support

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 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 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 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 will be described. The diagram shown in FIG. 6 is another embodiment of the schematic diagram of the intake system and the exhaust system, similar to the diagram shown in FIG.
An exhaust bypass path 70 is provided between the upstream side of the exhaust turbine 45 of the supercharger TB and the aftertreatment device 46, and a first valve 71 is provided in the exhaust bypass path 70.

  In the forced (manual) regeneration of the DPF 46b, the airframe is stopped, the engine speed is the idling speed, and post injection is performed after the main injection. The forced regeneration of the DPF 46b is performed in a state where the airframe is stopped because there is a possibility that the PM clogged state in the DPF 46b is saturated and the DPF 46b is damaged when the airframe is further driven.

  Thus, since manual regeneration of the DPF 46b is performed at the idling speed, it takes time to reach a reproducible temperature because the exhaust temperature is low. In particular, in an engine equipped with a supercharger TB, the exhaust turbine 45 becomes a resistance, so that it takes time to increase the exhaust temperature.

  Therefore, when performing manual regeneration of the DPF 46b, the first valve 71 of the exhaust bypass path 70 is fully opened. As a result, part of the exhaust gas does not pass through the exhaust turbine 45, so that the exhaust gas quickly rises to the regeneration temperature without causing a decrease in the exhaust temperature. When manual regeneration is not performed, the first valve 71 is fully closed.

  The second valve 73 is also provided in the normal exhaust path 72 on the exhaust turbine 45 side. When the manual regeneration of the DPF 46b is performed, the time for the regeneration temperature to reach is shortened by fully closing the second valve 73.

  Further, the temperature sensor 74 on the upstream side of the post-processing device 46 is configured to close the first valve 71 when the temperature becomes too high during manual regeneration. Thereby, the damage etc. of the post-processing apparatus 46 can be prevented.

  Further, a temperature sensor 74a is provided on the downstream side of the post-processing device 46, and the first valve 71 is not closed when the detected value is not more than a predetermined value. Thereby, the reproduction | regeneration of DPF46b becomes favorable.

  The first valve 71 and the second valve 73 are variably controlled in order to set the value of the temperature sensor 74 to an appropriate value. As a result, the exhaust gas temperature can be raised quickly and the exhaust gas temperature can be prevented from becoming too high.

  FIG. 7 is a simplified schematic diagram of an exhaust system, but an exhaust system having a valve 79, a blower 76, and a burner 75 is provided separately from the normal exhaust system 78. When the DPF 46b is regenerated, the burner 75 is ignited, the blower 76 is driven by the belt 77 from the engine E, and the valve 79 is opened. Thereby, since high temperature gas is sent to DPF46b, reproduction | regeneration of DPF46b becomes favorable.

  Further, a fuel injection device 83 is provided in the normal exhaust system 78. When the valve 79 is closed or the burner 75 is not provided and the DPF 46b is automatically regenerated, the fuel is oxidatively burned in the DOC 46a by injecting the fuel from the fuel injection device 83, and the high-temperature gas is generated. The flow of the DPF 46b improves the regeneration of the DPF 46b.

  FIG. 8 shows a method of regenerating the DPF 46b without starting the engine E. That is, the external introduction pipe 80 is connected to the upstream side of the DPF 46b, and the high-temperature gas generated from an external high-temperature generator (such as kerosene burner 81) is sent to the DPF 46b to regenerate the DPF 46b. As a result, the DPF 46b can be regenerated with low noise.

  Further, during manual regeneration of the DPF 46b, if it is a tractor, the work equipment 21 mounted on the rear part may be lifted and lowered continuously. Moreover, if it is a combine, you may raise / lower the mowing apparatus of the front part of a body continuously. As a result, a load is applied to the engine, so that the exhaust temperature rises quickly and the regeneration of the DPF 46b is improved.

  In addition, by intentionally applying a load to the engine in this way, it is possible to automatically reduce the engine speed after post injection. Therefore, it becomes possible to prevent a part of the fuel from being mixed into the oil.

  In the tractor, there is a light load work (scratching etc.) depending on the work. At this time, even if the DFP 46b is to be automatically regenerated, the DPF 46b may not be regenerated because the exhaust temperature rise is slow due to a small load. Therefore, as shown in FIG. 9, when the light load operation is performed, the light load mode switch 82 is intentionally turned on. As a result, the post injection amount is increased or the pump relieving load is applied, so that the exhaust temperature rises quickly and the regeneration of the DPF 46b can be performed satisfactorily.

  Further, when the engine load is less than or equal to a predetermined value, the above-described control is performed even if the light load mode switch 82 is not present or even if the light load mode switch 82 is forgotten to be turned on. You may comprise. The calculation of the load uses the maximum fuel injection amount that can maintain the set engine speed R as the denominator, and calculates the load factor using the current fuel injection amount that is used to actually maintain the engine speed as the numerator. calculate.

  In the tractor, the PTO rotation speed of the work machine (rotary) 21 can be selected. There are 1st speed, 2nd speed, 3rd speed, 4th speed, R speed and so on. The number of gears is determined according to the situation, but if the number of gears is low, the load acting on the engine is small. In such a case, since the exhaust temperature rise becomes dull, automatic regeneration of the DPF 46b cannot be performed satisfactorily. Thus, when the number of PTO gears is low, the post-injection fuel injection amount after the main injection is increased. As a result, the exhaust temperature rises, and the DPF 46b can be regenerated satisfactorily. FIG. 10 shows this flowchart.

  Further, a heater (not shown) may be wound around the DPF 46b, and when performing automatic regeneration of the DFP 46b, a current may be supplied from the storage battery to the heater to assist heating of the DPF 46b. FIG. 11 shows this flowchart.

  FIG. 12 shows a configuration in which a combustion chamber 84 is provided on the upstream side of the aftertreatment device 46. The fuel chamber 84 is provided with a first fuel injection valve 87 and an ignition glow plug 86. Further, the second fuel injection valve 88 is provided at a position away from the ignition glow plug 86. When the post-processing device 46 is regenerated, the fuel is injected from the first fuel injection valve 87 and the ignition glow plug 86 is energized to ignite the fuel. Accordingly, the high temperature exhaust gas flows into the post-processing device 46, so that the regeneration is good. Further, when fuel is injected from the second fuel injection valve 88 located away from the ignition glow plug 86, non-combustible fuel enters the DOC 46a and oxidizes and burns. As a result, further hot gas flows to the DPF 46b, so that regeneration can be performed quickly.

  Also, a hydraulic load device (not shown) is provided in the engine, and when the DPF 46b is regenerated, a load is applied to the engine by operating the hydraulic load device by driving the pump and the exhaust temperature rises quickly. I will do it.

  Further, when the drive of the work implement 21 is neutral and the traveling shift of the tractor is neutral, a load factor acting on the engine is calculated, and when the load factor is equal to or less than a predetermined value (idling of transmission). Is configured to automatically stop the engine after a certain time. As a result, fuel consumption is suppressed, and PM accumulation in the DPF 46b can be prevented. In addition, when the engine is stopped several times, the DPF 46b is forcibly regenerated.

  FIG. 13 shows a mounting support portion of the DPF 46b. A contact plate 90 is provided on the support plate 89, and the DPF 46 b is mounted on the engine or the like with a band 92 and a bolt 91. The DPF 46 b is in direct contact with the contact plate 90, and the contact plate 90 includes radiating fins 90 a. As a result, the heat release of the DPF 46b is moderately performed, so that an extreme temperature rise in the engine room can be prevented and deterioration of peripheral devices can be prevented.

  FIG. 14 shows a support structure of the DPF 46b. A pole 93 is provided on the engine, and the DPF 46 b is supported via the rotating portion 94. The rotating part 94 is fixed with bolts 95. At the time of inspection, the bolt 95 is removed and the DPF 46b is rotated in the direction of the arrow 96 with the rotating portion 94 as a fulcrum. Thereby, inspection maintenance becomes easy.

PM Granulated substance TB Supercharger E Diesel engine
46b Diesel particulate filter (DPF)
70 Exhaust bypass path 71 First valve 72 Normal exhaust path 73 Second valve 74 Upstream temperature sensor 74a Downstream temperature sensor

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 having a configuration for performing control, an exhaust path is configured to form a normal exhaust path (72) having a supercharger (TB) on the upstream side of the diesel particulate filter (46b) and bypass the normal exhaust path (72). A path (70) is configured, a first valve (71) is provided in the exhaust bypass path (70), and the first valve (71) is opened when the diesel particulate filter (46b) is regenerated. Work vehicle.   The second valve (73) is provided in the normal exhaust path (72), and the second valve (73) is closed when the diesel particulate filter (46b) is regenerated. Work vehicle.   A temperature sensor (74) is provided on the upstream side of the diesel particulate filter (46b), and the first valve (71) is closed when the detected value of the temperature sensor (74) exceeds a predetermined value. The work vehicle according to claim 1 or 2.   A temperature sensor (74a) is provided on the downstream side of the diesel particulate filter (46b), and the first valve (71) is not closed when the detected value of the temperature sensor (74a) is a predetermined value or less. The work vehicle according to claim 3.

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