JP2011074787A - Tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively use a low fuel consumption mode and a standard mode in a tractor of an agricultural machine. <P>SOLUTION: In the tractor which comprises an engine E containing a common rail 1, an ECU 100 controlling the engine E and a working machines 21, a performance curve indicating a relationship between engine rotation speed and torque is constituted of at least a standard mode line L1 and a low fuel consumption mode line L2 in the ECU 100. Switching between the standard mode line L1 and the low fuel consumption mode line L2 is performed by a fuel consumption mode changing means 36. When selecting the low fuel consumption mode line L2, the vehicle speed control of the tractor is carried out so as to maintain an engine load within a given range. When the engine load exceeds a given range in spite of the vehicle speed control, the mode is automatically switched to the standard mode line L1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tractor that is an agricultural machine.

  A configuration in which the output of the engine is switched to the standard mode or the energy saving mode depending on the state of a load acting on the engine is known (for example, see Patent Document 1).

JP 2007-231848 A

  In the above-described known technology, the engine performance curve is changed to the standard mode or the energy saving mode (low fuel consumption mode) depending on the state of the load acting on the engine. However, neither the vehicle speed control of the aircraft when the energy saving mode (low fuel consumption mode) is selected nor the technology for automatically shifting to the energy saving mode is disclosed, and thus there is a disadvantage that it cannot cope with an increase in engine load. .

  An object of the present invention is to eliminate the above-described problems.

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 an engine (E) having a common rail (1), an ECU (100) for controlling the engine (E), and a work implement (21), an ECU ( 100) includes at least a standard mode line (L1) and a low fuel consumption mode line (L2), and the standard mode line (L1) and the low fuel consumption mode line. Switching to (L2) is performed by the fuel consumption mode changing means (36), and when the low fuel consumption mode line (L2) is selected, the vehicle speed control of the tractor is performed so that the engine load is within a certain range. When the engine load exceeds a certain level in spite of the vehicle speed control, the standard mode line (L1) is automatically changed. It is obtained by a tractor, characterized in.

  Switching between the standard mode line (L1) and the low fuel consumption mode line (L2) is performed by the fuel consumption mode changing means (36). When the fuel efficiency mode line (L2) is selected, vehicle speed control is performed so that the engine load is within a certain range. In spite of this vehicle speed control, when the engine load becomes a certain level or higher, the mode is automatically switched to the standard mode line (L1).

  Since the present invention is configured as described above, in the first aspect of the present invention, when the low fuel consumption mode line (L2) (low output curve) is selected, the load factor is within a certain range so as to be constant. Since the vehicle speed of the HST is controlled by this, the fuel efficiency is improved. In addition, even if the vehicle speed control is performed, the engine is automatically switched to the standard mode line (L1) (high torque) when the load factor exceeds a certain value, so that a decrease in engine rotation can be reduced. The work can be continued.

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 Diagram showing the relationship between engine speed and output Flow chart when fuel efficient mode is selected Schematic diagram around the engine Side view around the engine Plan view showing the work process of the tractor (A) Side view of engine, (b) Rear view of engine Cross section of post-processing equipment Cross section of supercharger and aftertreatment device Cross section of supercharger and aftertreatment device

A 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 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 and the fuel injection nozzle 6, etc. Consists of ECU is an abbreviation for engine control unit.

As described above, the common rail 1 injects fuel to each cylinder 5 of the engine E, and supplies the fuel with 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, in the case of a tractor, the cultivated land is hard at the time of tillage work, and when the resistance is applied to the tillage 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 35 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 / lowers the working machine 21.

  The ECU 100 shown in FIG. 1 is connected to a control device 200 on the machine side. This control device 200 includes a plowing depth setting means (automatic plowing depth lever) 30 for automatically setting the plowing depth of the field, an automatic plowing depth switch 30a for turning on the functions of the plowing depth setting means 30, and a plowing depth. A selection switch (30b) for selecting either priority or vehicle speed priority and a monitor (M) are connected. FIG. 4 shows these arrangement positions.

  Then, when the automatic plowing depth switch 30a is in the on state, when the working switch 21 is driven in the state where either the plowing depth priority or the vehicle speed priority is selected by the selection switch 30b, the work traveling is started. The ECU 100 detects the engine load factor and transmits it to the control device 200 on the machine side. The control device 200 calculates the vehicle speed for maintaining the plowing depth or the plowing depth for maintaining the vehicle speed to the monitor M. It is configured to display. The engine load state is detected from the fuel injection state and the engine speed sensor E1, but other means may be used.

  As a result, an appropriate vehicle speed for maintaining the plowing depth or an appropriate plowing depth for maintaining the vehicle speed is displayed on the monitor M, so that good work can be performed without increasing the load on the engine E. In addition, excessive consumption of fuel can be suppressed. In particular, since the common rail 1 is mounted on the engine, fuel injection control for maintaining an appropriate vehicle speed can be performed with high accuracy, and fuel efficiency is improved.

  Further, the load state of the engine E is displayed on the monitor M when the automatic tilling switch 30a is in the cut state. Thus, when the automatic tilling switch 30a is in the off state, the load state of the engine E is displayed on the monitor M, so that the operator can easily check the load state of the engine E, and depending on the situation, the automatic tilling depth With the switch 30a and the selection switch 30b turned on, it is possible to quickly grasp the appropriate vehicle speed for maintaining the tilling depth or the appropriate tilling depth for maintaining the vehicle speed.

FIG. 5 is a performance curve showing the relationship between engine speed and output. Line L1 is the standard mode, and line L2 is the low fuel consumption mode.
Switching between the low fuel consumption mode line L2 and the standard mode line L1 is performed by the fuel consumption mode dial (fuel consumption mode changing means) 36, but a switch system may be used. The transition from the low fuel consumption mode line L2 to the standard mode line L1 is performed when a load acts on the vehicle. When the standard mode line L1 is used, the fuel injection timing is not advanced, but when the low fuel consumption mode line L2 is used, the fuel injection timing is advanced.

  Thus, when the load factor is low, the fuel efficiency is improved by using the low fuel consumption mode line L2 (low output curve), and when the load factor is high, the standard mode line L1 (high output curve) is used. Work is possible without reducing work efficiency. In particular, when using the low fuel consumption mode line L2 (low output curve), the combustion efficiency is further increased and the fuel consumption is improved by advancing the injection timing.

  FIG. 6 is a flowchart when the low fuel consumption mode line L2 (low output curve) is selected. When the low fuel consumption mode line L2 (low output curve) is selected (step S1), the load factor is confirmed in step S2. If the load factor is less than 80% in step S3, vehicle speed control by HST is performed in step S4, and control is performed so that the load factor falls within a certain range. If the load factor is 80% or more in step S3, the process proceeds to step S5 and automatically shifts to the standard mode line L1.

  As described above, when the low fuel consumption mode line L2 (low output curve) is selected, the HST vehicle speed is controlled within a certain range so that the load factor is constant. In addition, even if the vehicle speed control is performed, when the load factor exceeds a certain value, the mode is automatically switched to the standard mode line L1 (high torque), so that the engine rotation can be reduced and the operation can be reduced. Can be continued.

  In step S4 of FIG. 6 described above, the load factor is controlled to be within a certain range by the vehicle speed control by HST. However, in the tractor, the load factor is maintained within a certain range by plowing depth control for plowing the field. You may comprise. Further, the load factor may be controlled by shifting the sub-shift.

  FIG. 7 is a schematic diagram of the engine E. Reference numeral 38 denotes an air cleaner, 39 denotes an intercooler, 40 denotes a sub air cleaner, and 41 denotes a pressure accumulation tank. A supercharger 42 includes an intake turbine 42a and an exhaust turbine 42b. 43 is a switching valve and 44 is a check valve. 48 is an intake manifold and 49 is an exhaust manifold. 47 is a post-processing apparatus.

  The post-processing device 47 will be described. The exhaust gas discharged from the engine cylinder passes through the aftertreatment device 47 and is discharged from the muffler into the atmosphere. The post-treatment device 47 includes an oxidation catalyst (DOC) 45 and a diesel particulate filter (DPF) 46.

The oxidation catalyst (DOC) 45 burns the incombustible material chamber, and the diesel particulate filter (DPF) 46 is for collecting particulate matter (PM).
When the temperature of the exhaust gas is low (low load) continues for a long time, the DPF 46 has a concern that the granulated material (PM) accumulates and the capacity is lowered. Therefore, a configuration is adopted in which control for regenerating the DPF 46 is performed. When the pressure difference between the pressure sensors provided before and after the post-processing device 47 increases, it is determined that PM is clogged, and a warning is issued to the driver to prompt the regeneration of the DPF 46. In the regeneration of the DPF 46, the airframe is stopped, the engine is idled, the exhaust gas temperature is raised to a specified temperature, and the PM in the DPF 46 is burned off. As a result, excessive accumulation of PM in the DPF 46 can be prevented.

  At the time of manual regeneration of the DPF 46, the switching valve 43 provided on the downstream side of the intercooler 39 is operated to fill the pressure accumulating tank 41 without supplying the compressed air downstream of the supercharger 42 to the engine. The intake air to the engine E is supplied through the sub air cleaner. Although the engine E is driven by natural intake air, since the air charge to the accumulator tank 41 is added as a load to the engine via the compressor of the supercharger 42, the fuel injection amount and the unburned fuel amount increase early. The DPF 46 can be regenerated.

  It goes without saying that control is performed so that the pressure in the pressure accumulating tank 41 does not become excessive. And after DPF46 reproduction | regeneration, the path | route to the pressure accumulation tank 41 side is closed. The intake air pressurized by the compressor by the check valve 44 is configured not to flow back to the sub air cleaner 40 side. The compressed air accumulated in the pressure accumulation tank 41 can be used for other purposes. For example, a nozzle may be attached and used for cleaning the machine body.

  As shown in FIG. 8, a radiator fan 51, a radiator 50, an intercooler 39, and a shutter 52 are arranged in front of the engine E. As described above, when the DPF 46 is regenerated, the shutter 52 in front of the intercooler 39 is closed so that intake air is not cooled. By not cooling the intake air, the exhaust temperature rises and the regeneration of the DPF 46 can be completed quickly. Also, by not cooling the intake air, the temperature in the cylinder of the engine rises and the fuel that has undergone post injection evaporates, thereby preventing white smoke and irritating odors.

  Further, the blade angle of the radiator fan 51 itself can be freely changed by a motor or the like. In the regeneration mode of the DPF 46, the fan blade angle of the radiator fan 51 is changed based on the difference between the target exhaust gas temperature and the actual exhaust gas temperature. That is, when the actual exhaust gas temperature is lower than the target exhaust gas temperature, control is performed so that the blown air amount is reduced. As a result, the regeneration time of the DPF 46, in which the temperature rise time of the exhaust gas temperature is shortened, is improved.

  The tractor has various engine operating conditions such as road driving, tilling work, 4WD driving, and loader work. For example, in the running state, the PM discharge amount increases although the load is small. On the other hand, in tillage work, although the load increases, the PM emission amount decreases. As described above, the PM discharge changes depending on the state. Therefore, the PM accumulation amount calculation correction map is provided for each work mode, and the PM accumulation amount calculation is corrected according to the operation mode. Thereby, it is possible to perform appropriate DPF regeneration according to the work mode.

  FIG. 9 shows a schematic diagram of the reciprocating work process of the tractor. As described above, normally, when the PM is accumulated to some extent in the DPF 46, the DPF 46 is regenerated. However, this regeneration time may be troublesome during the agricultural season. Therefore, as shown in the drawing, the DPF 46 is automatically regenerated by turning left and right twice each time during the tilling work in the field. Thus, by performing frequent regeneration, it is not necessary to spend time to regenerate the DPF 46. Further, since the DPF 46 is automatically regenerated when the left and right turns are performed twice and the next turn, the temperature rises quickly.

  The PM accumulation amount in the DPF 46 is determined from the differential pressure of the pressure sensors before and after the DPF 46, and the like. However, it is possible to prevent damage to the DPF 46 by estimating the PM accumulation amount with higher accuracy.

  Therefore, by program control, the engine is swept from intentional low idle to high idle, and the exhaust resistance and DPF differential pressure at high idle are measured, so the PM accumulation amount of DPF can be easily calculated and the load acts Even when it is not, it is configured to diagnose whether there is a risk of PM accumulation during high idle. As a result, it is possible to determine whether or not the danger zone has been reached at any pressure, so that it is possible to prevent damage to the DPF, fire, and the like.

  FIG. 10 shows a configuration in which the post-processing device 47 is attached to the engine E. In this embodiment, only the oxidation catalyst (DOC) 45 is used, but the DPF 46 may be provided on the downstream side of the DOC 45. The DOC 45 is obtained by supporting an oxidation catalyst on a ceramic honeycomb carrier. The cylindrical case 53 of the post-processing device 47 is assembled to the exhaust manifold 49 with bolts 55.

  As shown in FIG. 11, the post-processing device 47 has a configuration in which the DOC 45 is canned into the cylindrical case 53 having both ends opened and inserted into the cylindrical case 53. In this case, a mat 56 is interposed between the cylindrical case 53 and the DOC 45. The supercharger 42 is also assembled to the exhaust manifold 49, and the outlet of the supercharger 42 is assembled to one end of the cylindrical case 53 directly or via a spacer.

  The exhaust gas that is emitted by turning the turbine of the supercharger 42 has a swirling component, and enters the post-processing device 47 before it is attenuated, so that the gas can be rotated to the outer periphery even at a rapidly expanding portion of the cross section. . By disposing the aftertreatment device 47 in the immediate vicinity of the supercharger 42, it is possible to prevent the exhaust gas temperature from decreasing. In addition, the number of piping parts is reduced, and the mountability is light and compact. Further, the post-processing device 47 does not require complicated canning, and it is easy to set the size and the amount of precious metal supported in accordance with the engine specifications, and the cost can be reduced.

  The cylindrical case 53 may be integrated with the exhaust manifold 49. That is, the exhaust manifold 49 and the cylindrical case 53 are integrally formed of aluminum die casting, so that no mounting bolts or the like are required.

  FIG. 12 shows a connection configuration between the cylindrical case 53 of the post-processing device 47 and the supercharger 42. The cylindrical case 53 is connected to the turbine housing 42c of the supercharger 42 with a stud bolt 57 or the like. Thereby, the supercharger 42 and the post-processing device 47 can be stably supported. As shown in FIG. 13, a connecting flange 58 is provided between the turbine housing 42 c of the supercharger 42 and the cylindrical case 53 of the aftertreatment device 47, and the cylindrical case 53 is overloaded via the connecting flange 58. You may comprise so that it may attach to the feeder 42. FIG. Thereby, the further attachment strength comes to improve.

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

DESCRIPTION OF SYMBOLS 1 Common rail 21 Work machine 36 Fuel consumption mode change means 100 ECU
E Engine L1 Standard mode line L2 Low fuel consumption mode line

Claims (1)

  In a tractor equipped with an engine (E) having a common rail (1), an ECU (100) for controlling the engine (E), and a work implement (21), the engine speed and torque are included in the ECU (100). The performance curve indicating the relationship between the standard mode line (L1) and the low fuel consumption mode line (L2) is composed of at least the standard mode line (L1) and the low fuel consumption mode line (L2). Means (36), and when the low fuel consumption mode line (L2) is selected, the vehicle speed of the tractor is controlled so that the engine load is within a certain range. Regardless, the tractor is configured to automatically change to the standard mode line (L1) when the engine load exceeds a certain level.

Images