JP2008057391A - Work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To execute appropriate engine control according to the turning condition of a work vehicle. <P>SOLUTION: In the work vehicle equipped with a common rail type diesel engine 1, steering angle of a steering wheel by a driver is detected by a detection means in turning during work, and an engine control change over means changing engine control to isochronus control from speed droop control and lowering engine speed according to magnitude of steering angle when steering angle gets to predetermined angle or greater, and changing engine control to original speed droop control again when steering angle is returned to roughly straight travel condition of the work vehicle. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a work vehicle, and belongs to the field of switching engine control contents mainly based on the turning behavior of the work vehicle.

Conventionally, the steering direction and the steering angular velocity by the driver are detected, and when the steering in the direction in which the turning degree of the vehicle is reduced, the engine output adjustment amount is reduced and corrected based on the magnitude of the steering angular velocity. By quickly recovering from a state where the output torque of the engine has decreased, the driver does not feel the drag feeling of the behavior control. Further, when the steering direction and the steering angular velocity by the driver are detected and the steering in the direction in which the degree of turning of the vehicle is reduced, the braking force adjustment amount of the wheel is reduced and corrected based on the magnitude of the steering angular velocity. Further, it is disclosed whether the driver does not feel the drag feeling of the behavior control by quickly releasing the braking force applied to the wheel. (For example, see Patent Document 1)
JP 2001-82200 A

  However, as described above, when steering is performed in a direction in which the degree of turning of the vehicle is reduced, the steering output is limited to correction for reducing the engine output adjustment amount and the wheel braking force adjustment amount based on the magnitude of the steering angular velocity. Without changing the speed of a work vehicle, especially an agricultural machine, there are two types of engines: a case where the rotational speed is changed due to a load change, and a case where the rotational speed is constant and the output is changed according to the load even if the load changes. It is necessary to control.

  Therefore, in the present invention, these two types of engine control are intended to be appropriately changed according to the steering angle state of the steering wheel and the lifting / lowering state of the work implement.

  According to the first aspect of the present invention, in a work vehicle equipped with a common rail diesel engine (1), the steering angle of the steering wheel (2) by the driver is detected by the detecting means when turning during the work, and the steering angle is equal to or greater than a predetermined angle. Then, the engine control is switched from droop control to isochronous control, the engine speed is reduced according to the magnitude of the steering angle, and when the steering angle returns so that the work vehicle is substantially straight, the engine control is again performed. An engine control switching means for switching to the original droop control is provided.

  With such a configuration, the work vehicle is turned by operating the steering wheel (2) of the driver at the time of working. The steering angle at this time is detected by the detecting means, and when the detected value is a predetermined angle or more, turning is performed. Based on the judgment that it is performed, the engine control in the common rail diesel engine (1) is output from the droop control in which the output also fluctuates due to the fluctuation of the engine speed by the switching means. In addition to switching to isochronous control that changes according to the load, it is likely to cause inconvenience unless the turning speed is reduced as the steering angle increases, so control is performed to automatically reduce the engine speed according to the magnitude of the steering angle. .

  In such an isochronous control state, when the detected value of the steering angle returns to a steering angle at which the work vehicle is substantially straight, the engine control is again performed based on the determination that the turning of the work vehicle is almost completed. Is switched to the original droop control by the switching means, and the engine speed is automatically returned to the original control.

  According to the invention of claim 2, in a work vehicle equipped with a common rail type diesel engine (1), the raising / lowering state of the work machine (3) is detected by the detecting means when turning during work, and the work machine (3) is in the raised state. In some cases, the engine control is switched from droop control to isochronous control, the engine speed is reduced according to the magnitude of the left-right rotation difference of the drive wheels (4), and the engine is operated when the work implement (3) is in the lowered state. An engine control switching means for switching the control back to the original droop control is provided.

  With such a configuration, when turning is performed during work on the work vehicle, the raising / lowering state of the work machine (3) is detected by the detection means, and it is determined that the work machine (3) is in the raised state based on the detected value. When the engine control in the common rail type diesel engine (1) is switched by the switching means, the engine speed is constant even when the load fluctuates, and the output is changed according to the load. In addition to switching to the changed isochronous control, the greater the difference between the left and right rotations of the drive wheels (4), the more likely it will be inconvenient if the turning speed is reduced. Therefore, the engine speed is automatically reduced according to the magnitude of the difference in left and right rotations. Let control take place.

  In such an isochronous control state, when it is determined that the work implement (3) is in the lowered state based on the detected value of the lift state of the work implement (3), the engine control is again switched to the original droop control by the switching means. In addition, the engine speed is automatically returned to the original value.

  In the first aspect of the invention, as described above, the driver turns the vehicle by operating the steering wheel (2) during work. When the detected value of the steering angle at this time is equal to or greater than a predetermined angle, the engine control is changed from the droop control. When switching to isochronous control, the engine speed is automatically reduced according to the magnitude of the steering angle, and when the detected value of the steering angle returns to the steering angle at which the work vehicle is substantially straight, Since engine control is switched to the original droop control and the engine speed is also automatically restored, when turning on a work vehicle, for example, on a farm field, a large output is required around the undercarriage. By switching the normal engine control from normal droop control to isochronous control, it becomes possible to perform powerful turning even if the load increases during turning. In addition, smooth and lossless turning can be performed by reducing the engine speed and decreasing the vehicle speed according to the magnitude of the steering angle.

  According to the second aspect of the present invention, as described above, when turning is performed during work, when the work implement (3) is in the raised state, the engine control is switched from droop control to isochronous control, and the drive wheel (4) is rotated left and right. The engine speed is automatically reduced according to the magnitude of the difference, and when the work implement (3) is in the lowered state, the engine control is switched again to the original droop control, and the engine speed is also automatically restored. Since it is to be returned, when turning on a work vehicle, for example, in a farm field or the like, a large output is required for the undercarriage, so by switching the engine control at this time from normal droop control to isochronous control, Even if the load increases during turning, powerful turning can be performed, and the smaller the turning difference between the left and right drive wheels (4) due to one brake, etc., the smaller the turning. Because, by dropping the speed to reduce the engine speed in accordance with the rotational difference, it is possible to perform turning without smooth and loss.

  In a work vehicle equipped with the common rail type diesel engine 1, the steering angle of the steering wheel 2 by the driver is detected by the detecting means when turning during operation, and when the steering angle is greater than a predetermined accuracy (0 degree or more), the engine control is droop controlled. Switch to isochronous control to reduce the engine speed according to the steering angle, and provide engine control switching means to switch the engine control back to the original droop control when the steering angle returns to approximately 0 degrees ing.

  Further, in the work vehicle, when the work machine 3 is turned during the turn, the raising / lowering state of the work machine 3 is detected by the detecting means. When the work machine 3 is in the raised state, the engine control is switched from droop control to isochronous control. An engine control switching means is provided for reducing the engine speed according to the magnitude of the rotation difference and switching the engine control to the original droop control again when the work implement 3 is in the lowered state.

Embodiments of the present invention will be described below with reference to the drawings.
An outline of the common rail diesel engine 1 will be described with reference to a system diagram as shown in FIG. The common rail type (accumulation type fuel injection) is performed via a common rail 10 (accumulation chamber) having a required pressure for fuel supply to a fuel injection device that injects fuel into each cylinder.

  The fuel in the fuel tank 11 is sucked into the high pressure pump 13 driven by the engine 1 through the fuel filter 12 through the suction passage, and the high pressure fuel pressurized by the high pressure pump 13 is guided to the common rail 10 through the discharge passage 14. It is stored.

  The high-pressure fuel in the common rail 10 is supplied to the fuel injection valves 17 corresponding to the number of cylinders through the high-pressure fuel supply passages 16, and the fuel injection valves 17 for each cylinder based on commands from the engine control unit 18 (hereinafter referred to as ECU). Is opened, high pressure fuel is injected and supplied into each combustion chamber of the engine, and surplus fuel (return fuel) in each fuel injection valve 17 is led to a common return passage 20 by each return passage 19, and this return It is returned to the fuel tank 11 by the passage 20.

  Further, a pressure control valve 21 is provided in the high-pressure pump 13 for controlling the fuel pressure (common rail pressure) in the common rail 10, and this pressure control valve 21 is sent from the high-pressure pump 13 to the fuel tank 11 by a duty signal from the ECU 18. The flow area of the return passage 20 for surplus fuel to the fuel is adjusted, and thereby the fuel discharge amount to the common rail 10 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 21 so that the common rail pressure detected by the rail pressure sensor 22 matches the target common rail pressure. .

  As shown in FIG. 2, the ECU 18 of the common rail diesel engine 1 in the work vehicle (agricultural work machine) has three types of control modes, that is, a travel mode M1, a normal work mode M2, and a heavy work mode M3 in relation to the rotational speed and the output torque. Provided.

  The traveling mode M1 is used when traveling without farming as droop control in which the output fluctuates due to fluctuations in the rotational speed. For example, when the traveling speed is reduced or stopped by applying a brake, As the traveling load increases, the engine speed decreases, so the traveling speed can be reduced or stopped safely.

  The normal work mode M2 is used when performing normal farm work as isochronous control in which the rotation speed is constant even when the load fluctuates and the output is changed according to the load. Sometimes, when the cultivated land is hard and resistance is applied to the cultivator blade, the combine makes it easy for the operator to control the output and maintain the rotational speed even when the harvest is heavy and the load increases during harvesting operations.

  In the heavy work mode M3, as in the normal work mode M2, the isochronous control that changes the output according to the load at a constant rotation speed even when the load fluctuates, and when the load limit is approached, the rotation speed is increased to increase the output. Control with heavy load control, especially used when farming near the load limit.For example, when plowing with a tractor, engine output even when encountering hard cultivated land Increases beyond the normal limit, so work is not interrupted.

  These work modes M1, M2, and M3 are configured to be switched by an operation of a work mode changeover switch, a shift operation of a travel shift lever, an operation of turning on and off a work clutch, or the like.

  Conventionally, in a diesel engine, it is known to perform pilot injection that injects a small amount of fuel in a pulse manner prior to main injection, thereby shortening the ignition delay and reducing the so-called knocking noise peculiar to the diesel engine. .

  This pilot injection is performed once or twice before the main injection. However, by using the system of the common rail 10, the state of the pilot injection is changed according to the state of the engine. The generation of white smoke or black smoke due to noise reduction or incomplete combustion can be suppressed.

  The tractor 5 equipped with the common rail type diesel engine 1 is turned by operating the driver's handle 2 during work. A steering angle sensor 6 is provided as a detecting means for detecting the steering angle at this time. When the detected value by the sensor 6 is 0 degree or more, the engine control is switched from droop control to isochronous control, the engine speed is decreased according to the magnitude of the steering angle, and when the detected value returns to 0 degree, the engine A control switching device 7 as engine control switching means for switching the control to the original droop control is provided in the ECU 18 and configured.

  With such a configuration, as shown in the flowchart of FIG. 3, the turning steering angle by the driver's steering wheel 2 operation is detected by the steering angle sensor 6 during work, and the turning is performed when the detected value is 0 degree or more. Based on the determination, the engine control in the engine 1 is switched from droop control to isochronous control by the control switching device 7, and if the turning speed is reduced as the steering angle increases, the smoothness and loss are likely to occur. As shown in FIG. 4, smooth turning can be performed by automatically reducing the engine speed in accordance with the magnitude of the steering angle.

  In this isochronous control state, when the detected value by the steering angle sensor 6 returns to 0 degrees, the engine control is switched again to the original droop control by the control switching device 7 based on the determination that the turn is completed. The number is automatically restored.

  Further, in the tractor 5, the engine control is switched to isochronous control when turning at the time of work, and the speed change state in the speed change device that performs the traveling speed change, and the turning steering angle when the driver's handle 2 is operated by the steering angle sensor 6. Accordingly, the engine speed is decreased to reduce the vehicle speed. As shown in the diagram of FIG. 5, when the vehicle speed is high, the engine speed starts to decrease by a decrease start line a from a shallower steering angle stage. As the steering angle increases, the vehicle gradually decreases linearly in the isochronous control region, thereby making it possible to perform a smooth turn with little loss according to the vehicle speed.

  Further, as shown in the diagram of FIG. 6, a factor b for correcting the set rotational speed of the isochronous control is obtained from the amount and change rate of the turning steering angle when the steering wheel 2 is operated by the steering angle sensor 6, and the isochronous set rotation is obtained. The number of times is multiplied by a factor b to correct the rotational speed. Conventionally, however, the rotational speed is corrected automatically by automatically correcting the accelerator opening in accordance with the turning steering angle. Although there is accelerator control, automatic accelerator control by isochronous control is not found.

  Further, in the tractor 5, when the work implement 3 is turned, the lift state of the work implement 3 is detected by a work implement lift sensor 8 as a detecting means. The control is performed as a switching means for engine control that switches the engine control to the original droop control when the work equipment 3 is in the lowered state while switching and reducing the engine speed according to the magnitude of the left-right rotation difference of the drive wheels 4. A switching device 7 is provided and configured.

  With this configuration, as shown in the flowchart of FIG. 7, when turning is performed at the time of work, the working machine 3 is detected by the working machine lifting sensor 8 and the working machine 3 is in the raised state by the detected value. If it is determined that the engine control in the engine 1 is switched from droop control to isochronous control by the control switching device 7, and if the turning speed is decreased as the left-right rotation difference of the drive wheel 4 increases, non-smooth and loss occurs. Therefore, as shown in the diagram of FIG. 8, smooth turning can be performed by automatically reducing the engine speed in accordance with the magnitude of the left-right rotation difference.

  In this isochronous control state, when it is determined that the work implement 3 is in the lowered state based on the detection value of the work implement lift sensor 8, the engine switching is again switched to the original droop control by the control switching device 7, and the engine rotation is performed. The number is automatically restored.

  As described above, when it is determined that the work implement 3 is in the ascending state when the tractor 5 is turning, the engine 1 in the engine 1 is switched from droop control to isochronous control. When a full turn is made, the greater the difference in rotational distance between the front and rear wheels, the more smooth and loss is likely to occur unless the turning speed is reduced. Therefore, as shown in the diagram of FIG. By automatically reducing the rotational speed, the vehicle speed can be reduced and smooth turning can be performed.

  Further, in a combine equipped with the common rail diesel engine 1, the engine speed is reduced while performing isochronous control according to the vehicle speed during each turn by mild turn, brake turn, and spin turn as shown in the diagram of FIG. Therefore, as the vehicle turns deeper, such as a spin turn, or the vehicle speed increases, the rate of decrease in the engine speed increases. Therefore, the engine speed is changed linearly by isochronous control according to the type of turning. By slowing down the vehicle speed, it is possible to make a smooth turn with little loss.

  In the combine, when turning at the time of work, the engine control is switched to isochronous control, and as shown in the diagram of FIG. 11, the rotation difference between the left and right traveling crawlers becomes smaller as the vehicle speed turns faster. The engine rotation speed starts to decrease from the decrease start line c, and according to the vehicle speed, the engine speed is gradually decreased linearly and the vehicle speed is reduced by the isochronous control area as the traveling crawler rotation difference increases. Smooth turning with little loss can be performed.

  Further, in the above combine, when the direction is changed to the left and right when traveling at high speed compared to when traveling at low speed, the shock of the vehicle body becomes large and the driver feels uncomfortable even if the direction is corrected slightly. As shown in the diagrams (a) and (b), when the direction of the vehicle is changed at a high speed, the engine control is switched to isochronous control, and the engine speed is adjusted to the detected value of the rotation difference between the left and right traveling crawlers. Is temporarily reduced from the lowering start line d, and the engine speed is changed in accordance with the rotational difference of the traveling crawler, thereby making it possible to smoothly correct a small direction during high-speed traveling and to give the driver Shock can be reduced.

  In the isochronous control, when the load factor exceeds 100%, the engine speed suddenly decreases and the feeling to the driver becomes worse. Therefore, as shown in the flowchart of FIG. 13, when the load factor exceeds 75% It automatically switches to droop control, and when the load factor falls below 75%, engine control is performed to return to the original isochronous control. Since it is possible to recognize that the load factor is high, even if the engine speed is reduced exceeding 100% load, the impression is not deteriorated.

  In the rail pressure control at the time of engine acceleration by the common rail 10, the rail pressure at the conventional start cycle varies depending on the engine speed, and black smoke is observed at the time of acceleration. Therefore, as shown in the diagram of FIG. According to the rate of change of the number, it is classified into a constant rotation region, an acceleration region, a constant speed region, and a deceleration region, and the acceleration region is discriminated from the conventional rail pressure e as shown in the flowchart of FIG. In order to promote atomization and suppress the generation of black smoke during acceleration, the rail pressure is increased to the specified rail pressure g. The rail pressure can be controlled in advance.

  Further, when the engine is accelerated, a response delay of the main injection timing is likely to occur. In particular, when the injection timing is advanced or generation of white smoke is observed at a low temperature, the engine is shown in the diagram of FIG. As shown in the flowchart of FIG. 17, the acceleration region is classified into a constant rotation region, an acceleration region, a constant speed region, and a deceleration region according to the rate of change of the rotation number. In order to suppress the generation of white smoke during acceleration by reducing the advance amount of the injection timing to the prescribed injection timing k when the constant velocity region is determined next, the advanced injection timing j is determined. The main injection timing can be controlled in advance.

  Conventionally, all-speed governors used for off-road vehicles tend to discharge the fuel injection amount at full load depending on the engine load even when the accelerator opening is small. The increase in engine speed could not catch up with the opening, and a fake load was applied, causing a large amount of fuel near the full load to be injected and black smoke to be generated.

  Therefore, as shown in the diagram of FIG. 18, when the increase rate of the engine speed per unit time due to the accelerator opening is determined to be a free accelerator state by ΔNe / Δt, the engine speed control governor is displayed. By changing from the all speed governor control p to the limit speed governor control q, it is possible to limit the fuel injection amount with respect to the apparent load during acceleration and suppress the generation of black smoke.

  In the all-speed governor for off-road vehicles, as shown in the diagram of FIG. 19, the rate of increase in engine speed per unit time according to the accelerator opening is determined to be a free accelerator state based on ΔNe / Δt. When the engine speed control governor is set, the engine speed control governor is provided with a limiter r for the full load characteristic by the all speed governor control p, thereby limiting the apparent fuel injection amount during acceleration and suppressing the generation of black smoke. be able to.

  In the all-speed governor for off-road vehicles, as shown in the diagram of FIG. 20, the rate of increase in the engine speed per unit time according to the accelerator opening is determined to be a free accelerator state based on ΔNe / Δt. When this is done, the accelerator opening instruction can be changed from the requested accelerator instruction value s to the restrained accelerator instruction value t, so that the fuel control u without the instruction change can be changed to the fuel control v by the restraining instruction. The amount of fuel injection with respect to the apparent load during acceleration can be limited to suppress the generation of black smoke.

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

The system figure which shows the pressure accumulation type fuel injection diesel engine by a common rail. The diagram which shows the relationship between the engine speed and output torque by three types of control modes. The flowchart which shows the switching procedure of the engine control by a steering wheel steering angle. The diagram which shows the state of the fall of the engine speed according to the magnitude | size of a steering wheel steering angle. The diagram which shows the state which reduces an engine speed from a shallow steering angle, so that high-speed vehicle speed. The diagram which shows the factor for correction | amendment of the setting rotation speed by the change rate of a steering wheel steering angle. The flowchart which shows the switching procedure of the engine control by a working machine raising / lowering state. The diagram which shows the state which reduces an engine speed according to the left-right rotation difference of a driving wheel. The diagram which shows the state which reduces an engine speed according to the rotation distance difference of a front-and-back wheel. The diagram which shows the state of the engine speed reduction rate in the various turns of a combine. The diagram which shows the fall start line of an engine speed by the driving wheel rotation difference at the time of work turning. (A) The diagram which shows the engine speed fall start line by minute direction correction at the time of high speed.

(B) The diagram which shows the temporary reduction state of the engine speed by fine direction correction at the time of high speed.
The flowchart which shows the procedure which switches engine control by a load factor change. The diagram which shows the rail pressure increase state of the area | region classification by the change rate of an engine speed. The flowchart which shows the procedure of rail pressure increase / decrease in each area | region of engine speed. The diagram which shows the injection timing advance state of the area | region classification by the change rate of an engine speed. The flowchart which shows the procedure of the injection timing advance / delay in each area | region of engine speed. The diagram which shows the state which switches governor control in a free accelerator state. The diagram which shows the state of the limiter for governor control in a free accelerator state. The diagram which shows the state of an accelerator instruction | indication and fuel control in a free accelerator state. The schematic side view which shows the whole structure in a tractor.

Explanation of symbols

1. Common rail diesel engine Handle 3. Working machine 4. Driving wheel

Claims (2)

  In a work vehicle equipped with a common rail type diesel engine (1), the steering angle of the steering wheel (2) by the driver is detected by the detecting means when turning during operation, and when the steering angle exceeds a predetermined angle, engine control is started from droop control. An engine that switches to isochronous control, lowers the engine speed according to the magnitude of the steering angle, and switches the engine control back to the original droop control when the steering angle returns so that the work vehicle is almost straight ahead A work vehicle comprising a control switching means.   In a work vehicle equipped with a common rail type diesel engine (1), the lifting / lowering state of the work machine (3) is detected by the detecting means when turning during work, and when the work machine (3) is in the raised state, the engine control is droop controlled. Is switched to isochronous control, and the engine speed is reduced according to the magnitude of the left-right rotation difference of the drive wheel (4). When the work machine (3) is in the lowered state, the engine control is again controlled by the original droop control. An engine control switching means for switching to a work vehicle is provided.

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