KR20090110220A - Engine controller for work vehicle - Google Patents

Abstract

PURPOSE: An engine control apparatus for a work vehicle is provided to operate a fuel injection control unit based on the torque curve characteristic that engine rpm changes according to the change of torque. CONSTITUTION: An engine control apparatus for a work vehicle comprises first and second mode controllers(81,82), a control mode managing unit(94), a differential computing unit(95), and first and second engine load estimating units(81a,82a). The first and second mode controllers execute first and second mode control for determining the fuel injection amount of an engine based on first and second torque-engine rpm characteristics. The control mode managing unit selects the first or the second mode control. The differential computing unit calculates the difference between the unloaded engine rpm corresponding to an operating position detected by an operating position sensor(75) and the engine rpm detected by an rpm sensor(72). The first and second engine load estimating units estimate the engine load based on the rpm in the first mode control and on the fuel injection amount in the second mode control.

Description

ENGINE CONTROLLER FOR WORK VEHICLE}

This invention is connected with the operation position detection sensor which detects the operation position of the accelerator operation tool artificially operated, the rotation speed sensor which detects the rotation speed of an engine, and the fuel injection control unit which controls the fuel injection quantity of the said engine. An engine control apparatus for a work vehicle.

A tractor, which is an example of a work vehicle, generally includes an artificially operated accelerator operation tool (hand accelerator lever or accelerator pedal), a fuel injection control unit for controlling the fuel injection amount of the engine, and a rotation speed sensor for detecting the engine speed. Doing. The engine control device operates the fuel injection control unit on the basis of the torque curve characteristic in which the rotation speed of the engine fluctuates with the fluctuation of the torque. This engine control device has an all-speed governor function, a load control function, and a droop control function.

The torque curve characteristic is previously requested and tabulated as a relationship between the engine speed and the torque as a parameter for calculating the control amount sent to the fuel injection control unit. From this table, the relationship between the torque for each operation position of the accelerator operation tool and the engine speed can be extracted. As a result, when the accelerator operating tool is operated at a predetermined operation position, the torque curve characteristic is based on the torque value corresponding to this operation position and the detected value of the rotation speed sensor (actual engine speed) at that time. The control amount for the fuel injection control unit of the engine is calculated by this. Based on this control amount, the fuel injection control unit controls the fuel injection mechanism so that the required fuel injection amount is realized.

As mentioned above, the tractor equipped with the control apparatus which employ | adopted the control technique is known from Unexamined-Japanese-Patent No. 8-244488. The control device of the tractor has a difference between the rotational speed (defined for each operation position) of the engine in the no-load state corresponding to the operation position of the accelerator operation tool and the detected value of the rotational speed sensor (actual engine speed). Is calculated, and the difference in the rotational speed is estimated as the load on the engine. And when operating the transmission for driving, this rotation speed difference and consequently engine load are used (specifically, based on the difference of rotation speed, the predetermined low pressure P3 of a hydraulic clutch is determined ( Paragraphs [0045], [0046], [0047], FIGS. 6 and 7 of Japanese Patent Application Laid-Open No. Hei 8-244488).

Recently, an engine having a control function, i.e., an isochronous control function, based on a torque curve characteristic having a small fluctuation in the engine speed with respect to a torque fluctuation, or a torque curve characteristic in which the engine speed does not change with respect to the torque fluctuation. It has been proposed to apply a control device for operating a fuel injection control unit to a work vehicle. When this isochronous control function is realized, the engine can be used as a driving source, and a work device (for example, a roll baler for grass, etc.) that can not exhibit a predetermined performance when the engine speed is changed can be equipped.

In order to realize a plurality of control functions that are completely different in form of control such as a droop control function and an isochronous control function, it is important to appropriately determine the load on the engine.

Therefore, an engine control apparatus for controlling a fuel injection control unit in a plurality of control modes, which has a function of properly estimating a load on an engine, is expected.

Engine control for a work vehicle connected with an operation position detection sensor that detects an operation position of an artificially operated accelerator operating tool, a rotation speed sensor that detects the rotation speed of the engine, and a fuel injection control unit that controls the fuel injection amount of the engine An engine control apparatus comprising: a first mode control unit configured to perform first mode control for calculating a fuel injection amount of the engine based on a first torque-engine rotational speed characteristic, the first torque-engine rotational speed A second mode control unit for executing a second mode control for calculating the fuel injection amount based on a second torque-engine rotational speed characteristic in which variation in rotational speed with respect to a variation in torque is small compared to the characteristic; and the first mode control; A control mode manager is provided to select the second mode control. Further, a difference calculating section for calculating a speed difference between the no-load engine speed corresponding to the operation position detected by the operation position detection sensor and the engine speed from the speed sensor is provided, and the first mode control unit further includes: And a first engine load estimator for estimating engine load based on the rotation speed difference when the first mode control is executed, and wherein the second mode control unit measures the fuel injection amount when the second mode control is executed. A second engine load estimating section for estimating engine load on the basis is provided.

In this configuration, the first mode control is set in the case of normal road running or work running. In the first mode control, the first torque-engine rotational speed characteristic corresponding to the operation position of the accelerator operating tool is set, and the engine is changed with respect to the change in torque based on the detected value of the rotational speed sensor (the actual engine speed). The first torque-engine revolution characteristic in which the rotational speed of the engine changes, the fuel injection amount of the engine is controlled.

In the first mode control, between the rotational speed (defined for each operation position) of the engine in the no-load state corresponding to the operation position of the accelerator operation tool and the detected value of the rotational speed sensor (actual engine speed) This difference is detected as a load on the engine (e.g., when the difference in the number of revolutions is large, it can be determined that the load on the engine is large, and when the difference in the number of revolutions is small, The load is small).

In addition, when using the working apparatus (for example, the roll baler for grass | grasslands etc.) which cannot exhibit predetermined | prescribed performance when the rotation speed of an engine changes, 2nd mode control is set. In the second mode control, the first torque is based on the rotation speed of the engine in the no-load state corresponding to the operation position of the accelerator operation tool (so that the engine speed at no load corresponding to the operation position of the accelerator operation tool is maintained). The second torque-engine rotational speed characteristic, in which the variation in the rotational speed with respect to the torque variation compared to the engine rotational speed characteristic, is controlled, and the fuel injection amount of the engine is controlled.

In the second mode control, the difference in the rotation speed hardly occurs between the rotational speed of the engine in the no-load state corresponding to the operation position of the accelerator operation tool and the detected value of the rotational speed sensor (the actual engine speed), This car cannot be detected as a load on the engine. However, in the second mode control, since the fuel injection amount changes, the load applied to the engine is detected based on the fuel injection amount (for example, if the fuel injection amount is large, it can be determined that the load on the engine is large and the fuel injection amount is increased). Less, it can be judged that the load on the engine is small).

In order to make the above-mentioned effects more effective, the isochronous control may be performed based on the torque-engine rotational speed characteristic in which the engine speed does not decrease between the torque and the maximum torque at no load. As a result, the operation of the transmission for traveling based on the load on the engine can be performed more appropriately.

In general, in the second mode control, for example, isochronous control operates stably in a state in which the accelerator operation tool is not operated very much, and in a state where the accelerator operation tool is operated relatively frequently, for example, in road driving, Can't work stably. In contrast, the first mode control can operate in response to this even when the accelerator operating tool is operated relatively frequently.

In view of this, as one of the preferred embodiments of the present invention, an operation behavior calculation unit for calculating the operation behavior of the accelerator operation tool is provided from the detection signal of the operation position detection sensor, and the operation behavior calculation unit is provided per unit time of the accelerator operation tool. When it is determined that the amount of manipulation is large, the control by the first mode control unit is forcibly selected, and when the operation behavior calculation unit calculates that the amount of operation per unit time of the accelerator operating tool is small, it is forced by the second mode control unit. The control is selected.

According to this configuration, for example, if the operation amount per unit time of the accelerator operation tool is large, the operation behavior calculation unit judges that the accelerator operation tool is operated relatively frequently, and the first mode control is automatically set. On the contrary, if the operation amount per unit time of the accelerator operation tool is small, it is determined that the accelerator operation tool is not operated very much, and the second mode control is automatically set. In this way, the first mode control or the second mode control is automatically appropriately set in accordance with the operation state of the accelerator operating tool.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of this invention is described based on an accompanying drawing. Features of one embodiment may be combined with features of another embodiment, and such combinations are included in the scope of the present invention unless a contradiction occurs.

FIG. 1 shows a power transmission system built in the mission case 8 of a four wheel drive tractor, which is an example of a work vehicle, in which the power of the engine 1 is a forward clutch 5 or a reverse clutch 6. ), Cylindrical shaft 7, first peripheral gear device 10 (corresponding to a traveling transmission device), second peripheral gear device 11, sub transmission device 12, and rear differential gear device 13 It is transmitted to the rear wheel 14 through. Power diverged from immediately before the rear wheel differential gear device 13 is transmitted to the front wheel 19 through the transmission shaft 15, the front wheel transmission 16 of the hydraulic clutch type, the front wheel transmission shaft 17, and the front wheel differential gear device 18. Is passed). Power of the engine 1 is transmitted to the PTO shaft 4 via the transmission shaft 2, the hydraulic multi-plate PTO clutch 3, and the PTO transmission 9.

As shown in FIG. 1, the forward clutch 5 and the reverse clutch 6 are hydraulic multi-plate type in which a friction plate (not shown) and a piston (not shown) are combined, and are pressed in a shut-off state. It is operated in the electric state by supplying. When the forward clutch 5 is operated in the electric state, the power of the engine 1 is transmitted directly from the forward clutch 5 to the cylindrical shaft 7 so that the machine main body advances. When the reverse clutch 6 is operated in the electric state, the power of the engine 1 is transmitted to the cylindrical shaft 7 in the reverse rotation state through the reverse clutch 6 and the electric shaft 20 and the machine main body reverses.

As shown in FIG. 1, the first peripheral gear 10 includes four hydraulic multi-plate type 1 speed clutch 21, 2 speed clutch 22, 3 speed clutch 23 and 4 speed clutch 24. Can be shifted in four stages by arranging them in parallel, and by operating one of the first to fourth speed clutches 21 to 24 in an electric state, the power of the cylindrical shaft 7 is shifted to four stages and the transmission shaft 25 Is passed). The first to fourth speed clutches 21 to 24 are pressed in a shut-off state and operated in an electric state by supplying hydraulic oil.

As shown in FIG. 1, the second peripheral gear 11 includes two hydraulic multi-plate low-speed clutches 26 (corresponding to driving hydraulic clutches), and high-speed clutch 27 (running hydraulic pressures). Clutches) are arranged in parallel, and by operating one of the low-speed and high-speed clutches 26 and 27 in an electric state, the power of the transmission shaft 25 is shifted in two stages so that the auxiliary transmission 12 Is passed to. The low speed and high speed clutches 26 and 27 are pressed in the shut-off state and operated in the electric state by supplying hydraulic oil.

The sub transmission device 12 is configured in a synchronized mesh format for sliding the shift member 53 and can be shifted in two stages, and is mechanically operated by the shift lever 28 shown in FIG. 2.

Next, the hydraulic circuits for the forward and reverse clutches 5 and 6 and the first and second peripheral gear devices 10 and 11 will be described.

As shown in FIG. 3, the electromagnetic proportional valve 35 for the forward and backward clutches 5 and 6 and the pilot operated switching valves 36a and 37a are provided in the flow path 30 from the pump 29. Pilot operated switching valves 31a, 32a, 33a, 34a for the first to fourth speed clutches 21 to 24, electromagnetic proportional valves 38 and 39 for the low speed clutch 26 and the high speed clutch 27; Is connected.

As shown in FIG. 3, a pilot operation type for the hydraulic clutch 41 for differential lock operation in the front wheel differential gear device 18 is provided in the flow path 40 branched from the flow path 30. Standard valve 45 of the pilot operated switching valve 44a and the front wheel transmission 16 to the hydraulic clutch 43 for differential lock operation in the rear differential gear device 13. And the pilot operated switching valves 47a and 48a for the speed increasing clutch 46 are connected. The switching valves 31a to 34a, 36a, 37a, 42a, 44a, 47a, 48a are pressed to the oil drainage position (blocked state) by a spring, and operated at the supply position (electric state) by supplying the pilot pressure. do.

As shown in FIG. 3, the pilot flow path 50 branches from the flow path 30 via the pressure-reducing valve 49, and the pilot flow path 50 switches the switching valves 31a to 34a, 36a, 37a, 42a, 44a, It is connected to the operation part of 47a, 48a, and the electromagnetic operation valve 31b, 32b, 33b, 34b, 36b, 37b, 42b, 44b, 47b, 48b is connected to the operation part. The electromagnetic operation valves 31b to 34b, 36b, 37b, 42b, 44b, 47b, 48b are pressed to the oil discharge position (blocked state) by a spring, and the electromagnetic operation valves 31b to 34b, 36b, 37b, 42b, 44b, When 47b and 48b are operated to a supply position, pilot pressure is supplied to the operation part of switching valves 31a-34a, 36a, 37a, 42a, 44a, 47a, 48a, and switching valves 31a-34a, 36a, 37a, 42a, 44a, 47a, 48a are operated to the supply position (electric state).

2, the electromagnetic proportional valve 35, the electromagnetic operating valves 31b to 34b, 36b, 37b, 42b, 44b, 47b and 48b and the electromagnetic proportional valves 38 and 39 are control devices. The control signal from 76 is operated.

Next, the structure of the operation part of the forward and backward clutches 5 and 6 and the 1st and 2nd main gear apparatuses 10 and 11 is demonstrated.

As shown in FIG. 3, the opening / closing valve 51 which can distribute pilot pressure from the operation part of switching valve 36a, 37a is provided, and the opening / closing valve 51 is urged to a closed position by a spring, A clutch pedal 52 for operating 51 in the open position is provided. As shown in FIG. 2, the base of the steering wheel 58 of the front wheel 19 is provided with the forward and backward lever 59 operable in the forward position F, the reverse position R, and the neutral position N, and the forward and backward lever ( The operation position of 59 is input to the control device 76 (as a forward lever position signal).

As typically shown in FIG. 2, a shift for sliding the shift lever 28 and the shift member 53 of the sub transmission 12 that is pivotally supported around the center of the transverse axis of the control part of the machine main body. The shaft 54 is mechanically linked by the linkage mechanism 55. By operating the shift lever 28 in the neutral position N, the low speed position L, and the high speed position H, the sub transmission 12 (shift member 53) is operated in the neutral position, the low speed position, and the high speed position. The position sensor 70 which detects the operation position of the shift lever 28 is provided, and the detection signal (shift lever position signal) of this position sensor 70 is input to the control apparatus 76. As shown in FIG.

As shown in FIG. 2, the lock pin 56 which can be pulled out and provided to the horizontal side part of the shift lever 28 is provided, and the operation button 57 which carries out the retraction operation of the lock pin 56 is carried out of the shift lever 28. As shown in FIG. It is provided in the upper part, and the operation position of the operation button 57 (as an operation button position signal) is input to the control apparatus 76. The lock pin 56 is pressed on the protruding side (paper surface right direction in Fig. 2) by a spring (not shown) (operation button 57 is also pressed on the protruding side in the paper surface left direction in Fig. 2), By coupling the lock pin 56 to the guide plate 60 of the fixing portion, the shift lever 28 is held in the neutral position N, the low speed position L and the high speed position H. When the operation button 57 is pushed and operated, the lock pin 56 is moved out, and the shift lever 28 can be operated to the neutral position N, the low speed position L, and the high speed position H. As shown in FIG.

As shown in FIG. 2, the shift up button 61 and the shift down button 62 are arrange | positioned up and down on the left and right side surface of the shift lever 28, and the shift up button 61 and the shift down button 62 are shown. When an operation signal (a shift up operation signal and a shift down operation signal) is input to the control device 76 and the shift up button 61 and the shift down button 62 are pressed and operated, the control device ( The first and second peripheral gear devices 10 and 11 are operated based on the control signal from 76.

As shown in FIG. 2, the seven-segment shift display unit 64, the forward clutch 5, and the reverse, which display shift positions (1 to 8 speeds) of the first and second peripheral gear devices 10 and 11. The forward ramp 65 and the reverse ramp 66, the shift lever 28, or the forward and backward lever 59, which indicate which of the clutches 6 are operated in the electric state, are shown operated in the neutral position N. FIG. A neutral lamp 67 is connected to the control device 76. These output devices are not shown but are provided in the tractor control unit. As shown in Figs. 2 and 3, a buzzer 71 and a pressure sensor 74 for detecting operating pressures of the forward and backward clutches 5 and 6 are provided, and the detection signal of the pressure sensor 74 is controlled. Input to device 76. Based on this, the shift display part 64, the forward clutch 5 and the reverse clutch 6, the neutral ramp 67, and the buzzer 71 are operated by the control signal from the control apparatus 76. FIG.

The control device 76 also generates and outputs a control amount for the fuel injection control unit 68 that controls the fuel injection amount of the engine 1.

The control apparatus 76 is comprised by the computer unit as a core member, hardware or software, or both. The main function made there is shown typically in FIG. First, the control part 80 which is a pivotal function of this control apparatus 76 carries out the 1st mode control part 81 which performs the 1st mode control which calculates the fuel injection quantity of the said engine based on a 1st torque-engine rotation speed characteristic. And second mode control for estimating the fuel injection amount based on the second torque-engine rotational speed characteristic in which the variation in the rotational speed with respect to the torque variation is small compared to the first torque-engine rotational speed characteristic. A fuel injection control amount calculation unit 83 for outputting a control amount to the second mode control unit 82 and the fuel injection control unit 68 is constructed. In addition, the first mode control unit 81 includes a first engine load estimating unit 81a for estimating an engine load based on the rotation speed difference when the first mode control is executed, and the second mode control unit ( 82 is provided with the 2nd engine load estimation part 82a which estimates an engine load based on the said fuel injection quantity at the time of performing the said 2nd mode control. In this embodiment, the second mode control is isochronous control based on a torque-engine rotational speed characteristic in which the engine rotational speed does not decrease between the torque and the maximum torque at no load.

Examples of the input signal processing system include an accelerator operation behavior calculation unit 91, an engine rotation speed acquisition unit 92, a no-load rotation speed calculation unit 93, and a control mode management unit 94. The accelerator operation behavior calculation unit 91 calculates the operation behavior of the accelerator operation tool 73 from the detection signal of the operation position detection sensor 75. The engine speed acquiring unit 92 calculates the engine speed based on the signal from the speed sensor 72. The no-load rotational speed calculation unit 93 calculates the no-load engine rotational speed corresponding to the operation position detected by the operation position detection sensor 75. The control mode manager 94 selects control by the first mode controller and control by the second mode controller.

Moreover, the difference calculating part 95 and the valve control part 96 are built in the control apparatus 76. FIG. The difference calculating unit 95 calculates a rotation speed difference between the engine speed calculated by the engine speed obtaining unit 92 and the no-load engine speed calculated by the no-load speed calculating unit 93. The valve control unit 96 operates the aforementioned various valve groups based on the control signals from the pressure sensors 63 and 74 and the control unit 80.

Although the control apparatus comprised in this way can perform various control, the typical control process is listed below.

(1) When the operation behavior calculation unit 91 calculates that the operation amount per unit time of the accelerator operation tool 73 is large, the control by the first mode control unit 81 is forcibly selected.

(2) When the operation behavior calculation unit 91 calculates that the operation amount per unit time of the accelerator operation tool 73 is small, the control by the second mode control unit 82 is forcibly selected.

(3) When sudden acceleration / deceleration is determined at the time of execution of the second mode control, the engine load estimation by the first engine load estimating unit 81a is executed.

(4) When the fuel injection amount enters the maximum area at the time of execution of the second mode control, the engine load estimation by the first engine load estimating unit 81a is executed.

(5) In the case where an artificially operated mode setter 69 is provided, the control mode managing unit 94 is controlled by the first mode control unit 81 based on the mode setting information from the mode setter 69. The control and the control by the second mode control unit 82 are selected.

Next, the operation of the forward and backward lever 59 will be described based on the flowchart in FIG. 5.

When the forward and backward lever 59 is operated to the forward position F (step S1), the operation current is supplied to the electromagnetic operation valve 36b so that the switching valve 36a is operated to the supply position, and the forward clutch 5 is in an electric state. Is operated (step S2), the forward lamp 65 is turned on (step S3). When the forward and backward lever 59 is operated in the reverse position R (step S1), the operation current is supplied to the electromagnetic operation valve 37b to operate the switching valve 37a to the supply position, and the reverse clutch 6 is driven. It is operated in the state (step S4), the reverse lamp 66 is lighted (step S5), and the buzzer 71 operates intermittently (step S6).

When the forward and backward lever 59 is operated at the neutral position N (step S1), the operating current to the electromagnetic operation valves 36b and 37b is cut off, and the switching valves 36a and 37a are operated to the oil draining position so that the forward and backward clutches can be operated. (5, 6) is operated in a cutoff state (step S7), and the neutral lamp 67 is turned on (step S8). When the clutch pedal 52 is stepped on, the on-off valve 51 is operated to the open position, the switching valves 36a and 37a are operated to the oil draining position, and the forward and reverse clutches 5 and 6 are operated to the shut-off state. The neutral lamp 67 lights up. When both the forward and backward clutches 5 and 6 are operated in the blocked state in this way, the power is cut off in the forward and reverse clutches 5 and 6, and the machine main body is stopped.

Next, the first mode control unit 81 (to realize the all-speed governor mode, the load control mode, the droop control mode) and the second operating the fuel injection control unit 68 for controlling the fuel injection amount of the engine 1 and the second The mode control unit 82 (realizing the isochronous control mode) will be described.

As shown in Fig. 2, the control system has an openness sensor of a potentiometer type that detects an operation position of a hand accelerator lever 73 (corresponding to an accelerator operation tool) and a hand accelerator lever 73 that are artificially operated. (Operation position detection sensor) 75, the rotation speed sensor 72 which detects rotation speed N2 of the actual engine 1, and the detection value of the opening degree sensor 75 and the rotation speed sensor 72 is It is input to the control device 76.

As shown in FIG. 6, the 1st mode control part 81 shows the 1st torque-engine rotational speed characteristic represented by the 1st torque-engine rotational speed curve G1 by which the rotational speed of the engine 1 changes with respect to a torque change. The first mode control unit 81 operates the fuel injection control unit 68 via the fuel injection control amount calculation unit 83 based on the first torque-engine rotational speed characteristic. The first torque-engine rotational speed curve G1 is set in advance as a relation between the rotational speed of the engine 1 and the operation position (torque) of the fuel injection control unit 68, and is set for each hand accelerator operation position.

As shown in FIG. 7, the 2nd torque engine speed with which the fluctuation of the rotation speed of the engine 1 is smaller than the 1st torque engine speed characteristic (1st torque engine speed curve G1) with respect to the fluctuation of torque. A second torque-engine rotational speed characteristic expressed as a second torque-engine rotational speed curve G2 in which the rotational speed of the engine 1 does not change with respect to a curve G2 or a change in torque is set in the second mode control unit 82. The second mode control unit 82 (isochronous control unit) operates the fuel injection control unit 68 through the fuel injection control amount calculation unit 83 based on the second torque-engine rotational speed characteristic. The second torque-engine rotational speed curve G2 is set in advance as a relation between the rotational speed of the engine 1 and the operation position (torque) of the fuel injection control unit 68, and the operation position of the hand accelerator lever 73. It is set every time.

The flow of the control mode based on the signal from the artificial operation mode setter 69 and the signal from the shift lever 28 will be described using the flowcharts of FIGS. 8 and 9.

As shown in FIG. 8, when the setting switch (mode setter) 69 is operated to a 1st position (step S11), the hand accelerator lever 73 is operated and the hand accelerator lever 73 is not operated. Regardless of the state, the first mode control unit 81 operates, the second mode control unit 82 (isochronous control unit) stops, and "1" is displayed in the flag M-Flag in order to remember that the first mode is selected. It is set (step S12).

Here, the first torque-engine rotational speed curve G1 corresponding to the operation position of the hand accelerator lever 73 is set and is based on the detected value of the rotational speed sensor 72 (the actual rotational speed of the engine 1). The control amount for the fuel injection control unit 68 is calculated with reference to the first torque-engine revolution curve G1, and the fuel injection control unit 68 operates based on the calculated control amount.

When the setting switch 69 is operated to the second position (step S11), the second mode control unit 82 (isochronous control unit) operates, the first mode control unit 81 stops, and remembers that the second mode is selected. In order to do this, "2" is set in the flag M-Flag (step S14). Here, the second torque engine speed curve G2 corresponding to the operation position of the hand accelerator lever 73 is set, so that the control amount for the fuel injection control unit 68 with reference to the second torque engine speed curve G2 is set. The fuel injection control unit 68 is operated based on the calculated control amount.

That is, when the setting switch 69 is operated to the second position (step S11), the hand accelerator lever 73 is not operated (the operation amount per unit time of the hand accelerator lever 73 is smaller than the set value). ), The process proceeds to step S14, where the second mode control unit 82 (isochronous control unit) is operated, and the first mode control unit 81 stops.

If the hand accelerator lever 73 is operated (the amount of operation per unit time of the hand accelerator lever 73 is larger than the set value) (step S13), the flow advances to step S12, where the first mode control unit ( 81 is activated, and the second mode control unit 82 (isochronous control unit) stops.

Next, the overall operation processing of the first and second peripheral gear devices 10 and 11 by pressing the shift up button 61 or the shift down button 62 will be described.

As shown in FIG. 1, since the first peripheral gear device 10 is shiftable in four stages and the second peripheral gear device 11 is shiftable in two stages, the first and second peripheral gear devices 10 may be shifted. , 11) can be shifted to eight steps. In the state where the low speed clutch 26 is operated in the electric state, the 1 to 4 speed clutches 21 to 24 correspond to the 1 to 4 speed shift positions, and the high speed clutch 27 is operated in the electric state. In the state, the first to fourth speed clutches 21 to 24 correspond to the shift positions of the fifth to eighth speeds.

Pressure sensors 63 and 74 for detecting the working pressure are provided in the first to fourth speed clutches 21 to 24 and the low speed and high speed clutches 26 and 27, respectively. As a result, the shift positions (1 to 8 speeds) of the current first and second peripheral gear devices 10 and 11 are detected, and the detected shift positions are displayed on the shift display unit 64.

In the above state, it is assumed that the shift up button 61 or the shift down button 62 has been pressed (steps S15 and S16). As shown by the solid line A1 (view point B1) in FIG. 10, when the shift up button 61 is pressed (step S15), the 1 to 4 speed clutches 21 to 24 on the one-step high speed side from the current shift position are shown. Starts to be operated in the electric state by the electromagnetic operation valves 31b to 34b (starting the step-up operation from the operating pressure in the cutoff state) (step S17). When the shift-down button 62 is pressed down (step S16), the 1 to 4 speed clutches 21 to 24 on the one-step lower speed side than the current shift position are operated in the electric state by the electromagnetic operation valves 31b to 34b. (Step S18).

In this case, in the state where the shift lever 28 is operated at the low speed position L or the high speed position H (step S19), the first mode control unit 81 is operated in step S20 (M-Flag = "1"). The predetermined low pressure P3 is set by the following operation (step S24).

Of the engine 1 in a no-load state (a state in which the forward and reverse clutches 5 and 6 are operated in a shut-off state and the PTO clutch 3 is operated in a shut-off state so that no load is applied to the engine 1). The relationship between the rotational speed and the operation position of the hand accelerator lever 73 (detected value of the opening degree sensor 75) is obtained in advance.

Thereby, referring to the above relationship on the basis of the operation position (detected value of the openness sensor 75) of the hand accelerator lever 73, the rotation speed N1 of the engine 1 in the no-load state is obtained ( Step S21), on the one hand, the rotation speed N2 of the actual engine 1 is detected by the rotation speed sensor 72 (step S22), and the rotation speed N1 and the rotation speed sensor ( The difference (speed difference N3) of the detected value (speed N2 of the actual engine 1) of 72 is detected (step S23), and the predetermined low pressure P3 is set based on the speed difference N3 (step S24). For example, it is judged that the load on the engine 1 is large, so that the rotation speed difference N3 is large, and the predetermined low pressure P3 is set to the high pressure side. The smaller the rotation speed difference N3, the smaller the load on the engine 1 is determined, and the predetermined low pressure P3 is set on the low pressure side (see solid line A2 in FIG. 10)].

In a state where the shift lever 28 is operated at the low speed position L or the high speed position H (step S19), when the second mode control unit 82 (isochronous control unit) operates in step 20 (M-Flag = "2 &Quot;), the predetermined low pressure P3 is set by the following operation (step S25).

When the second mode control unit 82 (isochronous control unit) operates, the detected value of the rotational speed sensor 72 (the rotational speed N2 of the actual engine 1) hardly changes, and the engine 1 in the no-load state The difference between the rotational speed N1 and the detected value of the rotational speed sensor 72 (the rotational speed N2 of the actual engine 1) (the rotational speed difference N3) hardly occurs. However, since the fuel injection amount by the fuel injection control unit 68 changes in the state in which the second mode control unit 82 (isochronous control unit) operates, the load applied to the engine 1 is detected based on the fuel injection amount. .

Thereby, the predetermined low pressure P3 is set based on the fuel injection amount (step S25) [For example, when the fuel injection amount is large, it is determined that the load on the engine 1 is large, and the predetermined low pressure P3 is set to the high pressure side. If the fuel injection amount is small, it is determined that the load on the engine 1 is small, and the predetermined low pressure P3 is set on the low pressure side (see solid line A2 in FIG. 10).

Next, the second half of the operation of the first and second peripheral gear devices 10 and 11 by pressing the shift up button 61 or the shift down button 62 will be described.

As described above, when the predetermined low pressure P3 is set (steps S24 and S25), as shown in the solid line A2 (view point B1) in Fig. 10, the operating pressure of the low speed or high speed clutches 26 and 27 operated in the electric state. The electromagnetic proportional valves 38 and 39 perform pressure reduction operation from the operating pressure P2 in the electric state to the predetermined low pressure P3 (step S26). In this case, at the time of the operation from the 4th speed shift position to the 5th speed shift position, the operating pressure of the low speed clutch 26 is decompressed to 0, and the operating pressure of the high speed clutch 27 is increased from 0 to the predetermined low pressure P3. do. On the contrary, at the time of the operation from the 5th speed shift position to the 4th speed shift position, the operating pressure of the high speed clutch 27 is decompressed to 0, and the operating pressure of the low speed clutch 26 is increased from 0 to a predetermined low pressure P3.

As shown by the solid line A1 (view point B2 to view point B3) in FIG. 10, the operating pressures of the first to fourth speed clutches 21 to 24 on the one-step high speed side or the one-step low speed side are the electromagnetic operating valves 31b to 34b. ), And the pressure-operating operation is started at the operating pressure P1 in the electric state (by the steps S17 and S18 being continued). At the same time, as shown in the dashed-dotted line A3 (view point B2 to view point B3) in FIG. 10, the first to fourth speed clutches 21 to 24 before the pressing operation of the shift up button 61 or the shift down button 62. (Operating pressure of the first to fourth speed clutches 21 to 24 that were operated in the electric state before the operation of pressing the shift up button 61 or the shift down button 62) is applied to the electromagnetic operation valves 31b to 34b. By this, pressure reduction operation to 0 is started from the operating pressure P1 in the electric state (step S27).

With the shift lever 28 operated to the low speed position L or the high speed position H (step S28), as shown in the solid line A2 (view point B3 to point B4) in FIG. 10, the low speed clutch 26 or the high speed clutch ( The operating pressure of 27 is gradually boosted and operated from the predetermined low pressure P3 by the electromagnetic proportional valves 38 and 39 (step S29). As a result, the power of the first to fourth speed clutches 21 to 24 on the first stage high speed side or the first stage low speed side starts to be transmitted through the low speed clutch 26 or the high speed clutch 27.

As shown in the time point B4 of the solid line A2 in FIG. 10, when the pressure sensor 63 detects that the operating pressure of the low speed clutch 26 or the high speed clutch 27 reaches the operating pressure P2 in the electric state (step) It is determined that the shift operation by the pressing operation of the shift up button 61 or the shift down button 62 is finished, and the shift position after the shift operation is displayed on the shift display unit 64 (step S31), and the buzzer ( 71) operates only once, and the operator is notified of the end of the shift operation (step S32). This shifts to step S11, and the shift operation by the next pushing operation of the shift up button 61 or the shift down button 62 becomes possible.

When the shift lever 28 is operated to the neutral position N, since the sub transmission 12 (shift member 53) is operated to the neutral position, the machine main body is stopped. When the shift lever 28 is operated to the neutral position N, when the shift up button 61 or the shift down button 62 is pressed (steps S15 and S16), as described above, the first and the second Peripheral gear devices 10 and 11 (1 to 4 speed clutches 21 to 24, low speed and high speed clutches 26 and 27) are operated on the one-step high speed side or the one-step low speed side (steps S17, S18, S27), the shift position after the shift operation is displayed on the shift display portion 64 (step S31), and the buzzer 71 operates only once (step S32).

In this case, since the main body of the machine is stopped, the decompression operation to the predetermined low pressure P3 of the low or high speed clutches 26 and 27, such as steps S20 to S26 and S29, and the step-up operation to the operating pressure P2 in the electric state are performed. It does not fall (step S19, S28).

Next, operation of the sub transmission device 12 by the shift lever 28 will be described.

As shown in FIG. 2, when the shift lever 28 is operated to the neutral position N, the sub transmission 12 (shift member 53) is operated to the neutral position. When the shift lever 28 is operated at the low speed position L, the sub transmission 12 (shift member 53) is operated at the low speed position, and when the shift lever 28 is operated at the high speed position H, the sub transmission device ( 12) [Shift member 53] is operated to the high speed position.

For example, the forward and backward lever 59 is operated to the forward position F (the forward clutch 5 is operated to the electric state, and the reverse clutch 6 is operated to the shutoff state), the shift lever 28 Is operated in the low speed position L (high speed position H) (the state in which the shift lever 28 is held in the low speed position L (high speed position H) by the operation button 57 and the lock pin 56), When the operation button 57 is pressed and the lock pin 56 is retracted from the guide plate 60, the switching valve 36a is operated to the oil drain position by the electromagnetic operation valve 36b, and the forward clutch 5 is operated. Is operated in the blocked state.

In this state, the shift lever 28 is operated from the low speed position L (high speed position H) to the neutral position N and the high speed position H (low speed position L) while the operation button 57 is pressed, and the operation button 57 is operated. ), The shift lever 28 is held in the neutral position N and the high speed position H (low speed position L) by the lock pin 56.

In this case, when the operation button 57 is returned and operated in the neutral position N of the shift lever 28, the switching valve 36a is operated to the supply position by the electromagnetic operation valve 36b, and the electromagnetic proportional valve 35 By this, the forward clutch 5 is immediately operated in the electric state. When the operation button 57 is returned and operated at the high speed position H (low speed position L) of the shift lever 28, the switching valve 36a is operated to the supply position by the electromagnetic operation valve 36b, and the electromagnetic proportional valve ( The forward clutch 5 is gradually operated in the electric state by the 35).

In the state where the forward and backward lever 59 is operated in the reverse position R (the state in which the reverse clutch 6 is operated in the electric state and the forward clutch 5 is operated in the blocked state), the shift lever as described above. When pressing and returning the operation button 57 of (28), the reverse clutch 6 is operated in the interruption | blocking and transmission state as mentioned above.

[Another first embodiment of the invention]

In the above-mentioned [details for carrying out the invention], the sub transmission device 12 shown in FIG. 1 is the same as the second main gear device 11, and a hydraulic multi-plate type low speed clutch (not shown) and a high speed. A clutch (not shown) may be arranged in parallel, and an electromagnetic proportional valve (not shown) may be provided for each of the low speed and high speed clutches of the sub transmission 12. In this configuration, the shift positions of 1 to 16 speeds are set by the second peripheral gear device 11 and the sub transmission device 12, and the shift up button 61 and the shift down button 62 are pressure-operated. Operation to the shift positions of 1 to 16 speeds becomes possible.

[Other Second Embodiment of the Invention]

Although the first peripheral gear device 10 and the second peripheral gear device 11 shown in FIG. 1 are configured in the form of a hydraulic clutch, the first peripheral gear device 10 and the second peripheral gear device 11 are formed. Similarly to the sub transmission 12, the shift member (not shown) may be configured in a gear shifting type in which the hydraulic member (not shown) slides with a hydraulic cylinder (not shown).

The work vehicle in which the first peripheral gear device 10 and the second peripheral gear device 11 are shiftable in 10 or 6 steps, and the sub transmission device 12 are configured in three stages of a high speed position, a medium speed position, and a low speed position. The present invention can also be applied to a work vehicle configured to be shiftable.

According to the present invention, the difference between the rotation speed N1 of the engine 1 and the detected value of the rotation speed sensor 72 (the rotation speed N2 of the actual engine 1) in the no-load state (speed difference N3), or the fuel injection amount Based on the above, the first and second peripheral gear devices 10 and 11 can also be applied to a work vehicle that is automatically shifted.

1 is a schematic diagram showing an electric system of a mission case.

2 is a block diagram of a control system.

3 is a hydraulic circuit diagram of a forward and reverse clutch, first and second peripheral gears, and the like.

4 is a block diagram of an engine control device.

Fig. 5 is a flowchart showing the flow of control when the forward and backward lever is operated.

6 is a diagram showing a first torque-engine revolution characteristic.

7 is a diagram showing a second torque-engine revolution characteristic.

Fig. 8 is a flowchart showing the flow of the first half of the control immediately before the shift up button and the shift down button are pressed.

Fig. 9 is a flowchart showing the flow of the second half of the control when the shift up button and the shift down button are pressed.

Fig. 10 is a diagram showing the pressure states of the first to fourth speed clutches, the low speed and the high speed clutch when the shift up button and the shift down button are pressed;

<Explanation of symbols for the main parts of the drawings>

1: engine

5: forward clutch

7: cylindrical shaft

10: first peripheral device

12: sub transmission device

13: Rear wheel differential gear device

51: on-off valve

54: shift axis

58: steering wheel

59: forward and backward lever

Claims (6)

An operation position detection sensor 75 for detecting an operation position of the accelerator operation tool 73 artificially operated, a rotation speed sensor 72 for detecting the rotation speed of the engine, and a fuel injection for controlling the fuel injection amount of the engine In the engine control apparatus for a work vehicle connected with the control unit 68, A first mode control unit 81 that executes first mode control for calculating a fuel injection amount of the engine based on a first torque-engine rotational speed characteristic; A second mode for executing a second mode control for calculating the fuel injection amount based on the second torque-engine rotational speed characteristic in which the rotational speed fluctuation with respect to the torque variation is small compared to the first torque-engine rotational speed characteristic; The control unit 82, A control mode manager 94 for selecting the first mode control and the second mode control, A difference calculating unit 95 for calculating a speed difference between the no-load engine speed corresponding to the operation position detected by the operation position detection sensor 75 and the engine speed from the speed sensor 72 is provided. Also The first mode control section 81 includes a first engine load estimating section 81a for estimating an engine load on the basis of the rotation speed difference when the first mode control is executed, And the second mode control section 82 includes a second engine load estimating section 82a for estimating engine load on the basis of the fuel injection amount when the second mode control is executed. Engine control unit. The engine control apparatus for a work vehicle according to claim 1, wherein the second mode control is isochronous control. The operation behavior calculation unit 91 according to claim 1, further comprising an operation behavior calculation unit 91 for calculating an operation behavior of the accelerator operation tool 73 from a detection signal of the operation position detection sensor 75, When the operation behavior calculation unit 91 calculates that the operation amount per unit time of the accelerator operation tool 73 is large, the first mode control is forcibly selected, And the second mode control is forcibly selected when the operation behavior calculation unit (91) calculates that the operation amount per unit time of the accelerator operation tool (73) is small. The estimation of the engine load by the first engine load estimating section 81a is executed according to any one of claims 1 to 3, when a sudden acceleration / deceleration is determined at the time of performing the second mode control. Engine control device for work vehicle which becomes. The engine control apparatus for a work vehicle according to claim 1, wherein when the fuel injection amount enters the maximum region at the time of performing the second mode control, estimation of the engine load by the first engine load estimation unit 81a is executed. . 2. The work vehicle is provided with a mode setter 69 which is artificially operated, and the control mode manager 94 controls the first mode control based on the mode setting information from the mode setter. An engine control apparatus for a work vehicle for selecting a second mode control.

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