JP5147613B2 - Farm tractor - Google Patents

Description

The present invention relates to a tractor for agricultural.

  2. Description of the Related Art Conventionally, a tractor as a work vehicle includes a traveling machine body equipped with a diesel engine having an electronic governor type fuel injection device, a work machine such as a front loader mounted on the traveling body so as to be movable up and down, and the power of the diesel engine. A hydraulic pump for supplying hydraulic oil to a hydraulic cylinder for the working machine, and a working machine operation lever for moving the working machine up and down.

  Conventionally, in a tractor which is an example of a work vehicle, an input system device (for example, a sensor or a setting device) for transmitting a control amount signal as a control target to a control means or detecting an operation amount of a control target. And an output system device (for example, various actuators) for driving the controlled object in accordance with a signal from the input system device. These input / output devices are usually controlled by control means such as a microcomputer.

Recently, a display unit such as a liquid crystal monitor is provided in the control unit of the tractor (see, for example, Patent Document 1). During road driving and various operations, tractor state information (for example, engine speed, vehicle speed, etc.) is displayed on the screen of the display means. Therefore, the operator can visually recognize the state of each part of the tractor by looking at the screen of the display means.
Japanese Patent Laid-Open No. 2001-37302

  By the way, during actual farm work, the function of each part of the tractor is often adjusted or inspected in accordance with the phenomenon / situation occurring in the tractor. When performing such maintenance work, it is necessary for the operator to understand the structure of the agricultural machine to some extent and to become familiar with the maintenance method. And until you become proficient, you will perform maintenance work while looking at the instruction manual of the tractor.

  However, it is extremely rare to bring instruction manuals to the field during farm work, and in many cases, the operator does not know which part should be inspected and how to perform maintenance work effectively. There was a problem. Among them, in particular, the engine inspection cannot be easily performed because an operator who understands the structure to some extent needs to use a dedicated diagnostic device.

  Accordingly, the present invention has been made to solve the above problems, and among them, it is a technical problem to make it possible to easily check the driving state of the engine.

The invention according to claim 1 is a traveling machine body on which a diesel engine having a common rail fuel injection device is mounted, an injection amount detecting means for detecting an injection amount of the common rail fuel injection device, and a rotational speed for detecting the engine rotational speed. A tractor for farm work comprising a detecting means and a plurality of control means for controlling various input / output devices, wherein the control means are electrically connected to each other, and the driving state of the diesel engine A test sequence for checking the vehicle is stored in advance, and one of the plurality of control units shifts to a diagnosis mode by a specific operation of an operation unit provided in the traveling machine body. and the traveling machine body is configured to execute the test sequence stored in said storage means in a state of being stopped, the test sequence, e The common rail type fuel so as to have an engine speed of the test pattern and a test pattern of the gin rotational speed and an allowable fluctuation region including a theoretical injection pattern of an injection amount corresponding to the test pattern. The injection amount of the injection device is changed, and the measurement result of the injection amount is compared with the allowable fluctuation region. The allowable fluctuation region of the test sequence is a value where the injection amount with respect to the engine speed is a normal value. A normal area and a caution area corresponding to a boundary between the normal area and the abnormal area, and during the execution of the test sequence, the running system operating means or the work machine system operating means among the operating means. Is manually operated, the value of the abnormal region is detected, or the value of the attention region is detected a predetermined number of times or more, the test Abort sequence, said once an engine speed of the diesel engine and is lowered to the idling rotational speed to stop the vehicle body, then, is that the is configured to stop the diesel engine.

  According to the present invention, a test sequence for checking a driving state of a diesel engine with a common rail fuel injection device is stored in advance, and one of the plurality of control means is a traveling machine body. The operation mode of the diesel engine is configured to execute the test sequence stored in the storage unit in a state where the traveling machine body is stopped in a state where the traveling machine body is stopped. Even an operator who does not know the mechanism can easily check the driving state of the diesel engine without using a dedicated diagnostic device.

  Hereinafter, an embodiment in which the present invention is embodied will be described with reference to the drawings when applied to a tractor as an example of a work vehicle. In FIG. 2, the cabin is not shown for convenience.

(1). First, an outline of a tractor will be described with reference to FIGS. 1 and 2.

  The traveling machine body 2 of the tractor 1 in the first embodiment is supported by a pair of left and right rear wheels 4 as well as a pair of left and right front wheels 3 as a traveling unit. The tractor 1 is configured to travel forward and backward by driving the rear wheels 4 and the front wheels 3 with a diesel engine 5 (hereinafter simply referred to as an engine) mounted on the front portion of the traveling machine body 2. The engine 5 is covered with a bonnet 6.

  A cabin 7 is installed on the upper surface of the traveling machine body 2, and a steering seat 8 and a steering handle 9 that moves the steering direction of the front wheel 3 to the left and right by steering are disposed in the cabin 7. Has been. A fuel tank 11 that supplies fuel to the engine 5 is provided below the bottom of the cabin 7.

  The steering handle 9 in the cabin 7 is provided on a steering column 25 erected in front of the steering seat 8. On the upper surface of the steering column 25, an instrument panel 26 indicating various information of the tractor 1 is disposed. A liquid crystal monitor 124 (see FIGS. 6 and 12) as a display means is provided below the instrument panel 26. On the right side of the steering column 25, there are disposed a throttle lever 30 for setting and maintaining the output rotational speed of the engine 5 and a pair of left and right brake pedals 31 for braking the left and right rear wheels 4. On the left side of the steering column 25, a forward / reverse switching lever 32 for switching the traveling direction of the traveling machine body 2 between forward and reverse, and a clutch pedal 33 for disengaging a main clutch (not shown) are arranged. Has been. A parking brake lever 34 is disposed on the back side of the steering column 25 to hold the left and right brake pedal 31 in the depressed position.

  On the right side of the steering column 25 in the floor plate 28 in the cabin 7 is an accelerator operating means for increasing and decelerating the engine speed in a range higher than the engine speed set by the throttle lever 30 as the minimum engine speed. The accelerator pedal 35 is arranged.

  On the left side of the control seat 8, a sub-transmission lever 40 as mode switching means for switching an output range from a mission case 17 described later between a low speed (work mode) and a high speed (travel mode), and driving of a PTO shaft 23 described later. A PTO speed change lever 36 for switching the speed is disposed. Here, among the modes selected by the auxiliary transmission lever 40, the work mode is a mode suitable for low-speed traveling such as during farm work. The traveling mode is a mode suitable for high speed traveling such as when traveling on the road. The mode switching means is not limited to the lever type, and may be a switch type.

  On the right side of the control seat 8, a main shift lever 38 for shifting operation, a loader lever 41 for operating a front loader 51 described later, and a tiller for manually changing and adjusting the height position of a rotary tiller 15 described later. An operation lever 39 is arranged. A differential lock pedal 37 for executing an operation of rotating the left and right rear wheels 4 at a constant speed is disposed below the control seat 8.

  The throttle lever 30, the forward / reverse switching lever 32, the accelerator pedal 35, the auxiliary transmission lever 40, and the main transmission lever 38 of the embodiment correspond to traveling system operation means related to the traveling operation of the traveling machine body 2. Further, the PTO transmission lever 36, the loader lever 41 and the tillage operation lever 39 correspond to work machine operation means related to the driving operation of the front loader 51 and the rotary tiller 39.

  On the other hand, the traveling machine body 2 includes an engine frame 14 having a front bumper 12 and a front axle case 13 and left and right machine body frames 16 that are detachably fixed to the rear portion of the engine frame 14 with bolts. A transmission case 17 is mounted on the rear part of the body frame 16 to transmit the rotational power from the engine 5 to the front and rear four wheels 3, 3, 4, 4 as appropriate. The rear wheel 4 is attached to the mission case 17 via a rear axle case 18 mounted so as to protrude outward from the outer surface of the mission case 17. Upper portions of the left and right rear wheels 4 are covered with a fender 19 fixed to the body frame 16.

  A hydraulic lifting mechanism 20 for lifting and lowering a rotary tiller 15 as a rear working machine is detachably attached to the rear upper surface of the mission case 17. The rotary cultivator 15 is connected to the rear portion of the mission case 17 via a three-point link mechanism including a pair of left and right lower links 21 and a top link 22. On the rear side surface of the mission case 17, a PTO shaft 23 for transmitting a PTO driving force to the rotary cultivator 15 protrudes backward.

  The hydraulic lift mechanism 20 is provided with a pair of left and right rear arms 46 that can be turned up and down by a single-acting lift control hydraulic cylinder 45 (see FIG. 3). The lower link 21 and the rear arm 46 on the left side in the traveling direction are connected via a left lift rod 47. The lower link 21 on the right side in the traveling direction and the rear arm 46 are connected to each other via a double-acting tilt control hydraulic cylinder 48 as a right lift rod and a piston rod 49.

  In this case, by manually operating the tillage control lever 39 on the right side of the control seat 8, the lift control hydraulic cylinder 45 is driven to extend and retract, so that the left and right rear arms 46 are turned up and down. The rotary cultivator 15 will move up and down.

  A front loader 51 as a front work machine is provided at the front of the traveling machine body 2. The front loader 51 includes loader posts 52 disposed on both left and right sides of the bonnet 6, a pair of left and right lift arms 53 connected to the upper ends of the loader posts 52 so as to be swingable up and down, and tips of the lift arms 53. And a bucket 54 connected to the portion so as to be swingable up and down.

  Each of the left and right loader posts 52 is erected on a post support member 55 that protrudes left and right outward from a midway portion of the body frame 16. Between one of the left and right loader posts 52 and the corresponding lift arm 53, a lift cylinder 56 for vertically swinging the lift arm 53 is provided. A bucket cylinder 58 for swinging the bucket 54 up and down is provided between the lateral frame 57 and the bucket 54 that connect between the longitudinal middle portions of the lift arms 53.

  In this case, by operating the loader lever 41 on the right side of the control seat 16 to expand and contract the lift cylinder 56 and the bucket cylinder 58, both the lift arms 53 and the bucket 54 swing up and down. When the rotary tiller 15 is used, the front loader 51 is removed because it is not used.

(2). Next, the hydraulic circuit structure of the tractor will be described with reference to FIG.

  The hydraulic circuit 60 of the tractor 1 includes a work machine hydraulic pump 61 as a hydraulic supply device that is driven by the rotational power of the engine 5, a lift control hydraulic cylinder 45 and a tilt control hydraulic cylinder 48 in the hydraulic lift mechanism 20. It has. The work machine hydraulic pump 61 is for supplying hydraulic oil to a lift control hydraulic cylinder 45, a tilt control hydraulic cylinder 48, a lift cylinder 56 and a bucket cylinder 58 as hydraulic actuators. In this case, the mission case 17 also functions as a hydraulic oil tank, and the hydraulic oil in the mission case 17 is supplied to the work machine hydraulic pump 61.

  The suction side of the work machine hydraulic pump 61 is connected to a strainer 62 disposed in the mission case 17 as a hydraulic oil tank. The discharge side of the work machine hydraulic pump 61 supplies the hydraulic oil to the ascending hydraulic solenoid valve 63 and the descending hydraulic electromagnetic valve 64 for controlling the supply of the hydraulic oil to the elevation control hydraulic cylinder 45 and the inclination control hydraulic cylinder 48. A tilt control electromagnetic valve 65 for control is connected via a first diversion valve 66.

  The ascending hydraulic solenoid valve 63 and the descending hydraulic solenoid valve 64 are automatically switched by driving the electromagnetic solenoid corresponding to the amount of manual operation of the tillage operation lever 39 and detection information such as a lift angle sensor 120 described later. It is configured. The inclination control electromagnetic valve 65 is automatically switched by driving an electromagnetic solenoid corresponding to detection information of a rolling sensor (not shown) and a work machine position sensor (not shown) arranged on the upper surface of the hydraulic lifting mechanism 20. It is configured to operate.

  When the ascending / descending hydraulic solenoid valves 63 and 64 are automatically switched in response to the manual operation amount of the tillage operation lever 39 and the detection information of the lift angle sensor 120, the elevating control hydraulic cylinder 45 is driven to expand and contract, The rear arm 46 is turned up and down. As a result, the rotary tiller 15 moves up and down via the left and right lower links 21.

  Further, when the tilt control electromagnetic valve 65 is automatically switched based on the detection information of the rolling sensor and the work machine position sensor, the tilt control hydraulic cylinder 48 is expanded and contracted, and the length of the piston rod 49 changes. As a result, the rotary cultivator 15 tilts left and right via the left and right lower links 21.

  A second diversion valve 67 is provided in the oil passage between the first diversion valve 66 and the rising hydraulic solenoid valve 63. A loader hydraulic circuit 70 is connected to the second branch valve 67 via a hydraulic coupler 68. The loader hydraulic circuit 70 includes a lift cylinder 56 and a bucket cylinder 58 for the front loader 51. In the embodiment, the discharge side of the hydraulic coupler 68 has a lift control electromagnetic valve 71 for controlling the supply of hydraulic oil to the lift cylinder 56 and a bucket control electromagnetic valve for controlling the supply of hydraulic oil to the bucket cylinder 58. 72 is branched and connected.

  The lift control electromagnetic valve 71 is configured to automatically perform switching operation by driving an electromagnetic solenoid corresponding to the forward / backward tilting operation of the loader lever 41. Further, the bucket control electromagnetic valve 72 is configured to automatically perform a switching operation by driving an electromagnetic solenoid corresponding to a left / right tilting operation of the loader lever 41.

  When the lift control solenoid valve 71 is automatically switched in response to the forward / backward tilting operation of the loader lever 41, the lift cylinder 56 is expanded and contracted to move the left and right lift arms 53 up and down, resulting in the bucket 54 moving up and down. become. Further, when the bucket control solenoid valve 72 is automatically switched in response to the left / right tilting operation of the loader lever 41, the bucket cylinder 58 is expanded and contracted to rotate the bucket 54 upward and perform a tilting operation for crushing soil or the like. Or a dumping operation of rotating the bucket 54 downward to drop soil or the like. The hydraulic circuit 60 and the loader hydraulic circuit 70 are also provided with a relief valve, a flow rate adjusting valve, a check valve, and the like.

(3). Next, the structure of the engine and its surroundings will be described with reference to FIGS.

  The engine 5 of the tractor 1 in the embodiment includes a cylinder block (not shown) having a cylinder head 74 fastened to an upper surface, and an exhaust manifold 75 is connected to one side surface of the cylinder head 74. The exhaust pipe 76 connected to the front end side of the exhaust manifold 75 is provided with a particulate filter 77 (hereinafter referred to as DPF) and a NOx catalyst 78 as a post-processing device. Exhaust gas discharged from each cylinder of the engine 5 to the exhaust manifold 75 is purified through the DPF 77 and the NOx catalyst 78 and then released to the outside.

  The DPF 77 is for collecting particulate matter (PM) and the like in the exhaust gas. Although not shown in detail, the DPF 77 of the embodiment has a structure in which an oxidation catalyst such as platinum and a honeycomb structure are arranged in series in a substantially cylindrical filter case in a casing made of a heat-resistant metal material. It has become.

  The NOx catalyst 78 is for reducing and detoxifying nitrogen oxides (NOx) in the exhaust gas. As the NOx catalyst 78 of the embodiment, a selective catalytic reduction catalyst using urea water as a reducing agent is adopted. doing. In this case, a urea supply device 79 for injecting an aqueous urea solution is connected between the DPF 77 and the NOx catalyst 78 in the exhaust pipe 76.

  As shown in FIG. 4, the engine 5 is associated with a common rail fuel injection device 80 as fuel supply means. The common rail fuel injection device 80 includes a plurality of injectors 81 (fuel injection valves) that inject high pressure fuel into each cylinder of the engine 5, a common rail 82 (pressure accumulation chamber) that accumulates high pressure fuel and distributes the fuel to each injector 81, A supply pump 83 that pressurizes the fuel sucked from the fuel tank 11 through the fuel filter 84 to a high pressure and then feeds the fuel to the common rail 82 is provided.

  Each injector 81 is connected to a common rail 82 via an individual high-pressure pipe 85, and the high-pressure fuel pumped from the common rail 82 is supplied to the combustion chamber of each cylinder while being opened and operated by a command from an engine controller 102 described later. It is comprised so that it may inject toward. A pressure sensor 86 for detecting the internal pressure (fuel pressure in the common rail 82) is attached to the common rail 82.

  The supply pump 83 is configured to be driven by the rotational power of the engine 5, and has a pressure control electromagnetic valve 87 for adjusting the fuel pumping amount to the common rail 82. The pressure control solenoid valve 87 controls the common rail internal pressure by adjusting the fuel pumping amount to the common rail 82 by increasing / decreasing the fuel return amount from the supply pump 83 to the fuel tank 11 according to the command of the engine controller 102. It is configured. The high pressure fuel injection pressure from each injector 81 is substantially equal to the common rail internal pressure. For this reason, the injection pressure of each injector 81 is indirectly controlled by the control of the common rail internal pressure by the pressure control electromagnetic valve 87.

  Each injector 81, common rail 82 and supply pump 83 are connected to the fuel tank 11 via a return pipe 88. A pressure limiter valve 89 is provided between the common rail 82 and the return pipe 88 to prevent the common rail internal pressure from increasing more than necessary. The aforementioned pressure control electromagnetic valve 87 is provided between the supply pump 83 and the return pipe 88. Excess fuel in each injector 81, common rail 82, and supply pump 83 is returned to the fuel tank 11 through the return pipe 88.

  As shown in FIG. 5, the common rail fuel injection device 80 is configured to execute the main injection A in the vicinity of the top dead center (TDC). In addition to the main injection A, the common rail fuel injection device 80 performs a small amount of pilot injection B for the purpose of reducing NOx and noise at the time of the crank angle θ1 that is about 60 ° before the top dead center. The pre-injection C is executed for the purpose of noise reduction at the crank angle θ2 just before the top dead center, or the particulate matter is reduced and the exhaust gas is purified at the crank angles θ3 and θ4 after the top dead center. For the purpose of promotion, after injection D and post injection E are executed.

(4). Configuration for Controlling Overall Operation of Tractor Next, a configuration for controlling overall operation of the tractor will be described with reference to FIG.

  The tractor 1 is equipped with a main machine controller 100, a work machine controller 101, and an engine controller 102 (engine control means) as control means. The controllers 100 to 102 control the overall operation of the tractor 1 and execute fuel injection control and mode switching control, which will be described later, display control of the liquid crystal monitor 124, and the like. These controllers 100 to 102 include CPUs 100a to 102a for executing various arithmetic processes and controls, PROMs 100b to 102b as storage means for storing control programs and data, and RAMs 100c to 100b for temporarily storing control programs and data. 102c, an input / output interface, and the like. The machine controller 100, the work machine controller 101, and the engine controller 102 are electrically connected to each other via a CAN communication bus 99.

  The controller 100 is connected to a battery 109 via a key switch 108 for applying power. The key switch 108 is configured to be connectable to a starter 110 for starting the engine 5.

  This machine controller 100 includes, as input / output devices, a main transmission potentiometer 111 that detects the operation position of the main transmission lever 38, a forward / reverse potentiometer 112 that detects the operation position of the forward / reverse switching lever 32, and the front and rear wheels 3 and 4. A vehicle speed sensor 113 for detecting the rotational speed (traveling speed), a parking brake sensor 114 for detecting the on / off state of the parking brake lever 34, an auxiliary transmission sensor 115 for detecting the operation position of the auxiliary transmission lever 40, and an operation position of the PTO transmission lever 36 Are connected to a PTO lever sensor 122 for detecting the above, a mode changeover switch 123 for activating a diagnostic mode to be described later, a liquid crystal monitor 124 as a display means, and the like.

  The work machine controller 101 includes, as input devices, a loader lever sensor 116 that detects the operation position of the loader lever 41, a lift sensor 117 that detects the vertical swing angle of the left and right lift arms 53, and the vertical swing angle of the bucket 54. Bucket sensor 118 to detect, tiller lever sensor 119 to detect the operation position of the tillage operation lever 39, lift angle sensor 120 to detect the rotation angle of the left and right rear arms 46, and the rotary tiller 15 are forcibly raised and lowered to a predetermined height. For this purpose, an automatic lift switch 121 and the like are connected.

  Further, the working machine controller 100 supplies hydraulic oil to an ascending hydraulic solenoid valve 63 and a descending hydraulic electromagnetic valve 64 and an inclination control hydraulic cylinder 48 for controlling the supply of hydraulic oil to the elevation control hydraulic cylinder 45 as output system equipment. A tilt control solenoid valve 65 for controlling, a lift control solenoid valve 71 for controlling supply of hydraulic fluid to the lift cylinder 56, a bucket control solenoid valve 72 for controlling supply of hydraulic fluid to the bucket cylinder 58, etc. are connected. Has been.

  The engine controller 102 operates the pressure control electromagnetic valve 87 based on the detection information of the pressure sensor 86 so as to obtain an appropriate common rail internal pressure corresponding to the driving state of the engine 5, and an appropriate value corresponding to the driving state of the engine 5. The fuel injection control is performed to open and close each injector 81 so that the injection timing and the injection amount are obtained.

  The engine controller 102 includes injectors 81 constituting the common rail fuel injection device 80, a pressure sensor 86 for detecting the common rail internal pressure, a pressure control solenoid valve 87 for adjusting the fuel pumping amount to the common rail 82, and the engine speed. An engine speed sensor 103 as a rotational speed detection means for detecting, an accelerator sensor 104 for detecting the depression amount of the accelerator pedal 35, a throttle potentiometer 105 for detecting an operation position of the throttle lever 30, and the like are connected.

  In principle, when the traveling machine body 2 is stopped, the engine controller 102 determines the high pressure from each injector 81 so that the actual engine speed detected by the engine speed sensor 103 matches the preset idling speed. The fuel injection pressure, the injection timing, and the injection amount (hereinafter referred to as a target injection pattern) are feedback-controlled. When the engine controller 102 is not in the stop state, the engine controller 102 feedback-controls the target injection pattern so that the actual engine speed matches the reference speed corresponding to the operation position of the throttle lever 30 (detection information of the throttle potentiometer 105). doing.

  Here, although not shown, the relationship between the engine speed and the target injection pattern is stored in advance in the engine controller 102 (for example, PROM 102b) in a map format or a function table format, for example. These relationships may be stored in the machine controller 100 or the work machine controller 101 in advance. Further, the combination data of the engine speed and the target injection pattern may be stored in the machine controller 100, the work machine controller 101, or the engine controller 102 as a table map.

  In the embodiment, the engine controller 102 determines the injection amount of the common rail fuel injection device 80 (the injection amount of the entire injector 81) based on the opening and opening time of each injector 81 and the injection pressure detected by the pressure sensor 86. ) Is calculated. That is, the engine controller 102 serves as an injection amount detection means for detecting the injection amount of the common rail fuel injection device 80.

(5). Description of Fuel Injection Control Next, an example of fuel injection control will be described with reference to the flowcharts shown in FIGS.

  As an example of fuel injection control, the engine controller 102 according to the embodiment performs common rail fuel injection according to the mode selected by the auxiliary transmission lever 40 and the state of the traveling vehicle body 2 when the accelerator pedal 35 is depressed. The apparatus 80 is configured to execute injection speed switching control for switching the injection speed of the main injection.

  The flow of the injection speed switching control will be described using the flowchart shown in FIG. In this case, it is assumed that the front loader 51 is attached to the front portion of the traveling machine body 2 and the rotary tiller 15 is removed. First, following the start of the injection speed switching control, the detected value of the engine rotation sensor 103, the detected value of the pressure sensor 86 on the common rail 82, the detected value of the accelerator sensor 104 corresponding to the operation amount of the accelerator pedal 35, The detection value of the shift sensor 115 is read (step S1).

  Next, it is determined from the detection value of the accelerator sensor 104 whether or not the operator is depressing the accelerator pedal 35 (step S2). If the accelerator pedal 35 is not depressed (S2: NO), the process returns. If the accelerator pedal 35 is depressed (S2: YES), the operation of the accelerator pedal 35 is performed based on the detected values read in step S1 and the map or function table stored in advance in the engine controller 102. A target engine speed corresponding to the amount and a target injection amount of each injector 81 in main injection corresponding to the target engine speed are calculated (step S3).

  Next, it is determined from the detection value of the auxiliary transmission sensor 115 whether the mode selected by the auxiliary transmission lever 40 is the work mode or the traveling mode (step S4). When the travel mode is selected (S4: travel), high pressure fuel corresponding to the target injection amount calculated in step S3 is injected from each injector 81 over time as appropriate during main injection, and the engine rotation The number is gradually increased to the target engine speed (step S5).

  When the operation mode is selected by the auxiliary transmission lever 40 (S4: operation), the detection value of the forward / reverse potentiometer 112, the detection value of the vehicle speed sensor 113, and the detection value of the parking brake sensor 114 are read (step S6), it is determined from these detection values whether the traveling machine body 2 is in a stopped state (step S7).

  If the traveling machine body 2 is not in the stopped state (S7: NO), the process proceeds to step S5 described above, and the engine speed is gradually increased to the target engine speed. If the traveling machine body 2 is in a stopped state (S7: YES), high pressure fuel corresponding to the target injection amount calculated in step S3 is injected at once from each injector 81 at the time of main injection, and the engine The engine speed is instantaneously increased to the target engine speed (step S8).

  In the work mode, when the traveling machine body 2 is stopped and the accelerator pedal 35 is depressed, the operator usually wants to increase the engine output in order to raise the front loader 51. In such a situation, as shown in step S8, the injection amount of the main injection is instantaneously increased and the engine speed is instantaneously increased to the target engine speed, so that the working machine driven by the rotational power of the engine 5 is used. The hydraulic oil discharge amount of the hydraulic pump 61 can be secured quickly and sufficiently. For this reason, after that, the operation responsiveness when the front loader 51 is moved upward by operating the loader lever 41 becomes reliable and quick, thereby contributing to the improvement of work efficiency.

  Further, when the accelerator pedal 35 is depressed in the work mode except for the state where the traveling machine body 2 is stopped, as shown in step S7, the injection amount of the main injection is increased appropriately over time, Since the engine speed is gradually increased to the target engine speed, the engine speed does not change abruptly even when the accelerator pedal 35 is depressed suddenly, for example, when traveling on the road. For this reason, it is possible to avoid a sudden speed change (rapid start / acceleration) of the traveling machine body 2 to ensure safety, and to improve the operational feeling and ride comfort.

  By the way, the engine controller 102 of the embodiment, as another example of the fuel injection control, performs the main injection of the common rail fuel injection device 80 while interlocking with the automatic lifting and lowering of the rotary tiller 15 mounted on the rear portion of the traveling machine body 2. It is comprised so that the raising / lowering interlocking control which increases / decreases an injection amount may be performed. Here, the set rotational speed, which will be described later, is set to a value (for example, about 1500 rpm) between a reference rotational speed corresponding to the operation position of the throttle lever 30 and the idling rotational speed, and is stored in advance in the engine controller 102 or the like. ing.

  The flow of the ascending / descending interlock control will be described using the flowchart shown in FIG. In this case, it is assumed that the rotary tiller 15 is attached to the rear portion of the traveling machine body 2 and the front loader 51 is removed. First, following the start of the lift interlock control, the detection value of the engine rotation sensor 103, the detection value of the pressure sensor 86 in the common rail 82, the set rotational speed stored in advance in the engine controller 102, and the detection value of the auxiliary transmission sensor 115 Is read (step S9), and it is determined from the detection value of the auxiliary transmission sensor 115 whether the mode selected by the auxiliary transmission lever 40 is the work mode or the traveling mode (step S10).

  When the traveling mode is selected (S10: traveling), it means that the tractor is not plowing, and the process returns as it is. When the work mode is selected (S10: work), it is next determined whether or not the automatic elevating switch 121 has been raised (step S11).

  The time when the automatic elevating switch 121 is raised is when, for example, the tractor 1 during the plowing operation reaches the vicinity of the headland in the field and tries to change the direction by 180 °. If the automatic elevating switch 121 has not been raised (S11: NO), the process returns. If the automatic elevating switch 121 is raised (S11: YES), the raising / lowering hydraulic cylinder 45 is shortened by switching operation of the raising hydraulic solenoid valve 63, and the rotary tiller 15 is forcibly raised to a predetermined height. (Step S12).

  Then, based on the set rotation speed read in step S9 and the map or function table stored in advance in the engine controller 102, the reduced injection amount of each injector 81 in the main injection corresponding to the set rotation speed is calculated. Calculation (step S13), high pressure fuel corresponding to the reduced injection amount is injected at once from each injector 81 at the time of main injection, and the engine speed is instantaneously lowered to the set speed (step S14). ).

  Next, it is determined whether or not the automatic lift switch 121 has been lowered (step S15). The time when the automatic elevating switch 121 is lowered is when, for example, the tractor 1 near the headland finishes changing the direction by 180 ° and moves forward. If the automatic elevating switch 121 has not been lowered (S15: NO), the process returns. If the automatic elevating switch 121 has been lowered (S15: YES), the elevating control hydraulic cylinder 45 is driven to extend by switching operation of the lowering hydraulic solenoid valve 64, and the rotary tiller 15 is forced to the original tillage height. Lower (step S16).

  Next, based on the original engine speed read in step S9 (before the upward movement) and a map or function table stored in advance in the engine controller 102, the main injection speed corresponding to the original engine speed is determined. The increased injection amount of each injector 81 is calculated (step S17), and high pressure fuel corresponding to the increased injection amount is injected at once from each injector 81 at the time of main injection, and the engine speed is not increased. The number of revolutions is instantaneously increased to (step S18).

  According to the above control, after the rotary tiller 15 moves up during the execution of the work mode, the injection amount of the main injection is instantaneously reduced and the engine speed is instantaneously lowered to the set speed. When the traveling machine body 2 reaches the headland near the farm and tries to change the direction by 180 °, the vehicle speed of the traveling machine body 2 can be quickly reduced. Therefore, the direction change operation of the traveling machine body 2 can be simplified while ensuring the safety during the direction change, and the operation burden on the operator can be reduced. Further, since the injection amount of the main injection is decreased after the rotary tiller 15 is moved up, there is no problem in securing the hydraulic oil discharge amount in the working machine hydraulic pump 61, and engine stall can be suppressed.

  Furthermore, when the rotary tiller 15 once moved up during the work mode is lowered, the injection amount of the main injection is increased instantaneously, and the engine speed is instantaneously changed to the engine speed before the upward movement. Therefore, for example, when the traveling machine body 2 near the headland finishes changing the direction of 180 ° and moves forward, the vehicle speed of the traveling machine body 2 can be quickly restored. Therefore, it is possible to smoothly shift to the subsequent cultivation work after the direction change, and the cultivation work for reciprocating the tractor 1 can be efficiently performed.

  The flowchart of FIG. 9 is another example of injection amount increase / decrease control. In this case, the engine controller 102 interlocks with the automatic raising / lowering of the rotary tiller 15 when switching the forward / backward traveling of the traveling machine body 2, and back-up / down interlocking control for increasing / decreasing the injection amount of the main injection in the common rail fuel injection device 80. Is configured to run. Also in this case, the set rotational speed is set to a value (for example, about 1500 rpm) between the reference rotational speed corresponding to the operation position of the throttle lever 30 and the idling rotational speed, and is stored in advance in the engine controller 102 or the like. Yes.

  As shown in the flowchart of FIG. 9, first, following the start of the back up / down interlock control, the detected value of the engine rotation sensor 103, the detected value of the pressure sensor 86 in the common rail 82, the set rotation speed stored in advance in the engine controller 102, Then, the detection value of the auxiliary transmission sensor 115 is read (step S19), and it is determined from the detection value of the auxiliary transmission sensor 115 whether the mode selected by the auxiliary transmission lever 40 is the work mode or the traveling mode (step S20).

  When the traveling mode is selected (S20: traveling), it means that the tractor is not plowing, and the process returns as it is. When the work mode is selected (S20: work), it is then determined whether or not the forward / reverse switching lever 32 has been operated backward based on the detection information of the forward / reverse potentiometer 112 (step S21).

  If the forward / reverse switching lever 32 is not operated backward (S21: NO), the process returns. If the forward / reverse switching lever 32 is operated backward (S21: YES), the lifting hydraulic cylinder 45 is shortened by switching operation of the rising hydraulic solenoid valve 63, and the rotary tiller 15 is forcibly raised to a predetermined height. (Step S22).

  Then, based on the set rotational speed read in step S19 and the map or function table stored in advance in the engine controller 102, the reduced injection amount of each injector 81 in the main injection corresponding to the set rotational speed is determined. Calculation (step S23), high pressure fuel corresponding to the reduced injection amount is injected at once from each injector 81 at the time of the main injection, and the engine speed is instantaneously lowered to the set speed (step S24). ).

  Next, it is determined whether or not the forward / reverse switching lever 32 has been operated forward (step S25). If the forward / reverse switching lever 32 is not operated forward (S25: NO), the process returns. If the forward / reverse switching lever 32 is operated forward (S25: YES), the lifting control hydraulic cylinder 45 is driven to extend by switching operation of the lowering hydraulic solenoid valve 64, and the rotary tiller 15 is forced to the original tillage height. (Step S26).

  Next, based on the original engine speed read before step S19 and the map or function table stored in advance in the engine controller 102, the main injection speed corresponding to the original engine speed is determined. The increased injection amount of each injector 81 is calculated (step S27), and high pressure fuel corresponding to the increased injection amount is injected at once from each injector 81 at the time of main injection, and the engine speed is not increased. The number of revolutions is instantaneously increased to (step S28).

  According to the above control, during the execution of the work mode, after the rotary tiller 15 moves up before the traveling machine body 2 moves backward, the injection amount of the main injection is instantaneously reduced, and the engine speed is set and rotated. The vehicle speed of the traveling machine body 2 can be quickly decelerated when the traveling machine body 2 moves backward. Accordingly, the backward operation of the traveling machine body 2 can be simplified while ensuring the safety during reverse travel, and the operation burden on the operator can be reduced. Further, since the injection amount of the main injection is decreased after the rotary tiller 15 is moved up, there is no problem in securing the hydraulic oil discharge amount in the working machine hydraulic pump 61, and engine stall can be suppressed.

  Furthermore, when the rotary tiller 15 once moved up before the traveling machine body 2 moves forward during the execution of the work mode, the injection amount of the main injection is increased instantaneously, and the engine speed is increased. Since the engine speed before the ascending movement is instantaneously restored, the vehicle speed of the traveling machine body 2 can be quickly returned to the original when the traveling machine body 2 is switched to the forward movement. Therefore, it is possible to smoothly shift to the subsequent tilling work after the forward / reverse switching, and the tilling work for reciprocating the tractor 1 can be performed efficiently.

  Note that the back up / down interlocking control described above can be executed even when the function of the forward / reverse switching lever 32 is replaced with a forward / reverse pedal.

(6). Details of Engine Diagnosis Control Next, details of engine diagnosis control will be described with reference to FIGS. 6 and 10 to 14.

  Now, as a mode (operation state) of the tractor 1, an initial mode, a normal mode (including the above-described work mode and travel mode) for executing road traveling and various farming operations, and a driving state of the engine 5 are checked. And a diagnostic mode for executing the test sequence TS.

  The work machine controller 101 shifts to a diagnosis mode by a specific operation of operating means (in the embodiment, the mode changeover switch 123 and the key switch 108) provided in the traveling machine body 2, and for engine diagnosis in a state where the traveling machine body 2 is stopped. The test sequence TS is executed. In the embodiment, the work machine controller 100 executes the diagnosis mode by a specific operation in which the key switch 108 is turned on while the mode switch 123 is pressed.

  In the diagnostic mode, since the driving state of the engine 5 is checked by executing the test sequence TS, the diagnostic mode is prohibited from starting in consideration of safety unless the specific operation procedure described above is performed. Further, in the diagnosis mode, unless the key switch is once turned off, returning to another mode such as the normal mode is also prohibited.

  The engine diagnosis test sequence TS is stored in advance in the PROM 101b of the work machine controller 101. The test sequence TS includes an engine speed test pattern Pr (see FIG. 10) and an injection amount allowable variation area Ar (see FIG. 11) corresponding to the test pattern Pr. The engine speed of the test pattern Pr Thus, the control program governs engine diagnostic control in which the injection amount of the common rail fuel injection device 80 is varied and the actual variation result is compared with the allowable variation region Ar.

  The engine speed test pattern Pr and the injection amount allowable variation area Ar corresponding to the test pattern Pr are stored in advance in the PROM 101b of the work machine controller 101 in a map format or a function table format, for example. 10 and 11 show a part of the test pattern Pr stored in the PROM 101b and a part of the allowable variation area Ar in a graph. In the graph of the test pattern Pr shown in FIG. 10, the time is taken on the horizontal axis and the engine speed is taken on the vertical axis. In the graph of the allowable fluctuation region Ar shown in FIG. 11, time is taken on the horizontal axis, and the injection amount of the common rail fuel injection device 80 (the injection amount of the injector 81 as a whole) is taken on the vertical axis.

  As shown in FIG. 10, the test pattern Pr is represented by a solid line that changes in an upwardly convex step shape. The two-dot chain line shown in FIG. 11 represents the theoretical injection pattern Pi corresponding to the theoretical value of the injection amount corresponding to the test pattern Pr. A region surrounded by the first upper limit line U1 and the first lower limit line D1 that are positioned symmetrically with respect to the theoretical injection pattern Pi is a normal region Ar1 in which the injection amount with respect to the engine speed is a normal value. Yes. Of the region surrounded by the second upper limit line U2 and the second lower limit line D2 that are positioned vertically symmetrically across the theoretical injection pattern Pi, the region excluding the normal region Ar1 is a normal region Ar1 and an abnormal region Ar3 described later. Is a caution area Ar2 corresponding to the boundary. The region above the second upper limit line U2 and below the second lower limit line D2 is an abnormal region Ar3 where the injection amount with respect to the engine speed is an abnormal value. A region surrounded by the second upper limit line U2 and the second lower limit line D2 (a combination of the normal region Ar1 and the attention region Ar2) is an allowable variation region Ar.

  In the PROM 101b of the work machine controller 101, various types of information such as characters, symbols, and images displayed on the liquid crystal monitor 124 of the instrument panel 26 are stored in advance regarding the mode (operation state) of the tractor 1. Examples of this type of information include normal mode information (not shown) and message information 131 to 138 (see FIG. 12) regarding execution of the test sequence TS.

  The flow of engine diagnosis control will be described using the flowchart shown in FIG. First, when the key switch 108 is turned on with the mode changeover switch 123 being pressed, the work machine controller 100 executes the diagnosis mode. In this case, first, following the start, the detected values of the forward / reverse potentiometer 112, the PTO lever sensor 122 and the parking brake sensor 114 are read (step S29), and then the forward / reverse switching lever 32 is detected from the detected value of the forward / reverse potentiometer 112. Is in the neutral position (step S30).

  If the forward / reverse switching lever 32 is not in the neutral position (S30: NO), if the test sequence TS is executed as it is, the traveling machine body 2 may move inadvertently. Message information 131 is displayed (step S31), and then the process returns to step S29. If the forward / reverse switching lever 32 is in the neutral position (S30: YES), it is then determined from the detection value of the PTO lever sensor 122 whether the PTO speed change lever 36 is in the neutral position (step S32).

  If the PTO speed change lever 36 is not in the neutral position (S32: NO), if the test sequence TS is executed as it is, the rotary tiller 15 may be inadvertently driven. Message information 132 is displayed (step S33), and then the process returns to step S29. If the PTO speed change lever 36 is in the neutral position (S32: YES), it is then determined from the detection value of the parking brake sensor 114 whether the parking brake lever 34 is in the engaged state (step S34).

  If the parking brake lever 34 is in the off state (S34: NO), there is a risk that the traveling machine body 2 will inadvertently move when the test sequence TS is executed. Is displayed (step S35), and then the process returns to step S29. If the parking brake lever 34 is in the engaged state (S34: YES), message information 134 "Start engine diagnosis" is displayed on the liquid crystal monitor 124 (step S36).

  Next, the test sequence TS stored in the PROM 101b of the work controller 101 is read (step S37), and the injection per unit time in which the actual engine speed detected by the engine speed sensor 103 becomes the engine speed of the test pattern Pr. An amount of high-pressure fuel is injected from each injector 81 (step S38).

  Next, the engine controller 102 calculates the actual measurement result of the injection amount per unit time based on the opening and opening time of each injector 81 and the injection pressure detected by the pressure sensor 86 (step S39). Then, the calculated actual measurement result is compared with the allowable variation area Ar of the injection amount corresponding to the test pattern Pr, and it is determined whether or not the actual measurement result is within the normal area Ar1 (step S40).

  If the actual measurement result per unit time is within the normal region Ar1 (S40: YES), then whether or not the cumulative time t from the time of the first injection disclosure in the test sequence TS is equal to or greater than the preset test time T. It discriminate | determines (step S41). If the test time T has not been reached (S41: NO), the process returns to step S38 described above. If the test time T has elapsed (S41: YES), the process proceeds to step S48 described later.

  In step S40, if the actual measurement result per unit time deviates from the normal area Ar1 (S40: NO), it is determined whether or not the actual measurement result is in the attention area Ar2 (step S42). If the actual measurement result is within the attention area Ar2 (S42: YES), it is then determined whether or not the number n of detections of the value of the attention area Ar2 is equal to or greater than a preset number N (step S43).

  If the number of detections n of the value of the attention area Ar2 is less than the set number N (S43: NO), the process proceeds to step S41 described above. If the number of detections n of the value of the attention area Ar2 is equal to or greater than the set number N (S43: YES), the process proceeds to step S44 described later.

  In step S42, if the actual measurement result per unit time deviates from the attention area Ar2 (S42: NO), the actual measurement result is the value of the abnormal area Ar3. The message information 135 is displayed (step S44). “There is a possibility and there is a danger, so the diagnosis is stopped and the engine is stopped. Please contact the store where you purchased the product”. Then, the test sequence TS is stopped (step S45), the injection amount of the common rail fuel injection device 80 is instantaneously reduced, and the engine speed is once reduced to the idling speed (step S46). The high-pressure fuel injection by the injection device 80 is stopped, and the driving of the engine 5 is stopped (step S47).

  In step S41, the test time T has elapsed (S41: YES), the process proceeds to step S48, and it is determined whether or not the number n of detections of the value of the attention area Ar2 is 0 (zero). If the number n of detections of the value of the attention area Ar2 is 0 (S48: YES), since all the measurement results are within the normal area Ar1, message information 136 “Engine status is normal” is displayed on the liquid crystal monitor 124. Is displayed (step S49).

  If the number of detections n of the value of the attention area Ar2 is not 0 (S48: NO), the value of the attention area Ar2 is detected less than N times in the actual measurement result. There is a possibility that there is a problem. It is recommended to check at the store where the product was purchased as soon as possible. "The message information 137 is displayed (step S50). During execution of the test sequence TS (steps S37 to S50), an alarm buzzer (not shown) may be intermittently sounded to alert the operator.

  According to the above control, the work machine controller 101 shifts to the diagnosis mode by a specific operation of the operating means (in the embodiment, the mode changeover switch 123 and the key switch 108) provided in the traveling machine body 2, and the traveling machine body 2 stops. In this state, the test sequence TS for engine diagnosis is executed, so even an operator who is not familiar with the mechanism of the engine 5 can easily check the driving state of the engine 5 without using a dedicated diagnostic device. it can.

  Moreover, the test sequence TS has a test pattern Pr for engine speed and an allowable variation area Ar including a theoretical injection pattern Pi of an injection amount corresponding to the test pattern Pr, and the engine speed of the test pattern Pr The injection amount of the common rail fuel injection device 80 is changed so as to be a number, and the measurement result of the injection amount is set to be compared with the allowable fluctuation region Ar. The engine diagnosis conditions (test sequence TS) are unified, and there is no room for human error (blur) in the diagnosis results. Therefore, highly accurate engine diagnosis can be performed.

  Further, the allowable variation area Ar of the test sequence TS is configured by a normal area Ar1 in which the injection amount with respect to the engine speed is a normal value, and a caution area Ar2 corresponding to the boundary between the normal area Ar1 and the abnormal area Ar3. Therefore, the presence of the attention area Ar2 makes it easier to predict a failure of the engine 5.

  Furthermore, the work machine controller 101 displays information on the diagnosis mode (for example, message information 131 to 137) on the liquid crystal monitor 124 of the instrument panel 26 during execution of the diagnosis mode, so that the operator 5 is alerted and the engine 5 The driving state can be accurately transmitted to the operator. As a result, if there is a malfunction in the engine 5, it can be quickly dealt with by repairing or ordering parts.

  In the embodiment, when the value of the abnormal area Ar3 is detected or the value of the attention area Ar2 is detected for a preset number of times N or more during the execution of the test sequence TS, the test sequence TS is stopped. (See step S44), it is possible to reliably avoid driving the engine 5 under a situation that may have a serious problem. Particularly in this case, since the engine 5 is stopped after the engine speed is set to the idling speed (see steps S46 and S47), the possibility that the traveling machine body 2 starts suddenly is remarkably suppressed. The safety of time can be secured.

  By the way, when the operator manually operates the travel system operation means 30, 32, 35, 38, 40 or the work system operation means 36, 39, 41 during the execution of the test sequence TS (see steps S37 to S50) The work machine controller 101 is configured to execute the interrupt process shown in FIG.

  The work machine controller 101 starts an interrupt processing routine. First, the message “Lever or pedal has been operated during engine diagnosis, the diagnosis is stopped and the engine is stopped.” Is displayed on the liquid crystal monitor 124. Information 138 is displayed (see step S51, FIG. 12 (h)). Then, the test sequence TS is stopped (step S52), the injection amount of the common rail fuel injection device 80 is instantaneously reduced, and the engine speed is once reduced to the idling speed (step S53). The high-pressure fuel injection by the injection device 80 is stopped, and the driving of the engine 5 is stopped (step S54).

  If the operator manually operates the traveling system operating means 30, 32, 35, 38, 40 or the work machine operating means 36, 39, 41 during the execution of the test sequence TS, the engine diagnosis condition (test sequence TS ) Will change. For this reason, in the embodiment, by forcibly stopping the engine diagnosis under such a situation, there is no room for error (blur) in the diagnosis result. In addition, in this case as well, the engine 5 is stopped after the engine speed is set to the idling speed, so that safety when the engine is stopped can be ensured.

  The control unit for executing the diagnosis mode may be the main controller 100 or the engine controller 102 (engine control unit). However, if a control unit other than the engine controller 102 is used as in the embodiment, the control unit operates on the engine controller 102. This is preferable because the load to be reduced can be reduced.

  In particular, in the embodiment, since the work machine controller 101 for controlling the work machine such as the front loader 51 and the rotary tiller 15 is used as the control means for executing the diagnosis mode, the machine controller 100 and the engine controller 102 Without changing the setting, it is possible to incorporate a unique setting for each work machine mounted on the traveling machine body 2 in the test sequence TS.

(7). Others The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, the present invention is not limited to a tractor but can be applied to agricultural machines such as rice transplanters and combines, and special work vehicles such as wheel loaders. In addition, the structure of each part is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention.

It is a side view of a tractor. It is a top view of a tractor. It is a hydraulic circuit diagram of a tractor. It is an approximate account figure showing an engine and a common rail type fuel injection device. It is a figure explaining the injection timing of a high pressure fuel. It is a functional block diagram of this machine controller and an engine controller. It is a flowchart of injection speed switching control. It is a flowchart of a raising / lowering interlocking control. It is a flowchart of back raising / lowering interlocking control. It is explanatory drawing which shows the test pattern of an engine speed. It is explanatory drawing which shows the allowable fluctuation | variation area | region of injection amount. It is explanatory drawing which shows the message information displayed on the liquid crystal monitor. It is a flowchart of engine diagnostic control. It is a flowchart of an interruption process.

DESCRIPTION OF SYMBOLS 1 Tractor 2 Traveling machine body 5 Engine 11 Fuel tank 15 Rotary tiller 30 Throttle lever 31 Brake pedal 32 Forward / reverse switching lever 35 Accelerator pedal 40 Sub shift lever 51 Front loader 80 Common rail type fuel injection device 81 Injector 82 Common rail 83 Supply pump 86 Pressure Sensor 87 Pressure control solenoid valve 100 Machine controller 101 Work machine controller 102 Engine controller 124 LCD monitor

Claims (1)

A traveling machine body equipped with a diesel engine having a common rail fuel injection device, an injection amount detection means for detecting the injection amount of the common rail fuel injection device, a rotation speed detection means for detecting the engine speed, and various inputs and outputs A plurality of control means for controlling the equipment, and a farm tractor in which the control means are electrically connected to each other,
A test sequence for checking the driving state of the diesel engine has storage means in which a test sequence is stored in advance.
One of the plurality of control means shifts to a diagnosis mode by a specific operation of an operating means provided on the traveling machine body, and the test sequence stored in the storage means in a state where the traveling machine body is stopped It is configured to perform a,
The test sequence has an engine speed test pattern and an allowable fluctuation region including a theoretical injection pattern of an injection amount corresponding to the test pattern, and the engine speed is the test pattern. , The injection amount of the common rail fuel injection device is changed, and the measurement result of the injection amount is compared with the allowable fluctuation region,
The allowable variation area of the test sequence includes a normal area where the injection amount with respect to the engine speed is a normal value, and a caution area corresponding to a boundary between the normal area and the abnormal area,
During the execution of the test sequence, the traveling system operating means or the work machine operating means among the operating means is manually operated, the value of the abnormal area is detected, or the value of the caution area is preset. If the set number of times is detected, the test sequence is stopped, the engine speed of the diesel engine is temporarily reduced to the idling speed and the traveling body is stopped, and then the diesel engine is stopped. It is configured,
Agricultural tractor .

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