JP2011127473A - Engine control device for work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely perform fuel-efficient operation by automatically performing troublesome switching of output modes of an engine in detecting the vertical movement of a working machine. <P>SOLUTION: In this engine control device for a work vehicle, a plurality of output modes of the engine 2 are provided, an engine mode selection means 97 is provided for selecting each output mode of the engine 2, and a vertical movement detection means 68 is provided for detecting the vertical movement of the working machine mounted on the work vehicle. When the upward-moving the operation is detected by the vertical movement detection means 68 during traveling with a power mode P selected by the engine mode selection means 97, the output mode of the engine is switched to an energy-saving mode S. When the downward movement of the working machine is detected by the vertical movement detection means 68, the output mode of the engine is switched to the power mode P. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine control device for a work vehicle on which a work machine is mounted so as to be movable up and down.

  In a working vehicle such as a construction machine, as described in Japanese Patent Application Laid-Open No. 2007-231849, an engine output torque curve in a standard mode that secures predetermined power and a fuel consumption reduction mode that reduces fuel consumption from the standard mode. There is a technology for switching an engine output torque curve with a switch provided in a driver's seat.

  Japanese Patent Application Laid-Open No. 2009-57978 determines whether excavation is being performed based on the selected speed stage of the transmission, the position or orientation of the work implement, and the traveling speed of the vehicle. In addition, it is determined whether uphill traveling is performed based on the vehicle front-rear inclination angle, traveling speed, accelerator pedal opening, and traveling acceleration, and excavation or uphill traveling is performed. A wheel loader is described in which the engine is operated with a high power output capability when running and at a low power output capability otherwise.

JP 2007-231849 A JP 2009-57978 A

  It is troublesome to switch the engine from the standard mode to the fuel consumption reduction mode with the switch provided in the driver's seat as needed, and switch to the standard mode when judging that the output is insufficient during use in the fuel consumption reduction mode. However, there is not much switching from the standard mode to the fuel consumption reduction mode.

In addition, the control for automatically switching to the fuel consumption reduction mode at the time of light work is troublesome and inaccurate in determining light work.
Therefore, an object of the present invention is to provide a tractor that can reliably perform work with low fuel consumption by automatically switching troublesome engine output modes by detecting the elevation of the work implement.

The problems of the present invention are solved by the following technical means.
According to the first aspect of the present invention, a plurality of output modes of the engine (2) are provided, and an engine mode selection means (97) for selecting the output mode of the engine (2) is provided so that the working machine mounted on the work vehicle can be moved up and down. When the elevating detection means (68) detects an increase in work while driving by selecting the power mode (P) by the engine mode selection means (97), an engine output is detected. The working vehicle is characterized in that the mode is switched to the energy saving mode (S), and the engine output mode is switched to the power mode (P) when the lifting detection means (68) detects the lowering of the work implement. This is an engine control device.

  The invention according to claim 2 is provided with an isochronous mode for maintaining a constant rotation of the engine (2) and a droop mode in which the rotation fluctuates according to a load, and the droop mode when the work machine is lifted during work traveling in the isochronous mode. The engine control device for a work vehicle according to claim 1, wherein when the work machine is lowered, the operation vehicle is returned to the isochronous mode.

  According to the first aspect of the present invention, since the high load state in which the work implement is used and the light load state in which the work implement is not used are determined by the lift detection means (68) of the work implement, the determination is simple and accurate. To automatically switch to fuel-saving work. In particular, even if the power mode (P) is selected by the engine mode selection means (97), since the construction is switched to the energy saving mode (S) when the work implement is lifted, the fuel consumption state is further reduced.

  In addition to the effect of the first aspect, when the work machine is lowered and used, the work according to the second aspect can continue the work to withstand heavy loads in the isochronous mode, and when the work machine is not used, In droop mode, the engine speed can be reduced and fuel consumption can be reduced.

It is a whole side view of a tractor of a present Example. It is an expansion perspective view around the cockpit of a tractor. It is a front view of a switch box. It is a power transmission diagram of a mission case. It is a block diagram of control. It is an output diagram of an engine. It is a flowchart figure of control. It is a flowchart figure of control. It is an electric tractor and a side view. It is a transmission mechanism figure of an electric tractor.

FIG. 1 shows a tractor 1 that is an agricultural machine as a work vehicle in which the present invention is implemented.
The tractor 1 has an engine 2 mounted in a bonnet at the front of the airframe, transmits the rotational power of the engine 2 to a transmission in the transmission case 3, and the rotational power reduced by the transmission is transmitted to the front wheels 4 and the rear wheels 5. To tell. The area around the cockpit 6 on the fuselage is covered with a cabin 7.

  As shown in FIGS. 2 and 3, a steering handle 8 is erected on the front side of the cockpit 6 inside the cabin 7, and a forward / reverse lever 9 is provided on the lower left side thereof. On the left side of the cockpit 6, a parking brake lever 10 and a first PTO transmission lever 11 and a second PTO transmission lever 12 for shifting the PTO shaft that outputs power to the work implement are arranged.

  The lower floor of the steering handle 8 is provided with a left brake pedal 56 that brakes the left and right front and rear wheels 4 and 5, a right brake pedal 57, and an all brake pedal 58 that brakes all the wheels at once. An accelerator pedal 13 is provided for controlling the rotation. This accelerator pedal 13 is used to adjust the traveling speed.

  When the accelerator pedal 13 is depressed to accelerate, it is used in the droop control of the normal work mode B, and the engine 2 is controlled by the droop control of the traveling mode A otherwise. Further, when the accelerator pedal 13 is depressed during traveling in the energy saving mode, the operation is switched to the normal operation mode B to accelerate.

  When the left brake pedal 56 and the right brake pedal 57 are depressed simultaneously, the brake is braked and the main gear shift stage is shifted to the low speed side to cause the engine brake to act. Further, when the left brake pedal 56 and the right brake pedal 57 are depressed more than a predetermined limit depression amount, the engine speed is decreased. At this time, if the left brake pedal 56 and the right brake pedal 57 are depressed and restored, the engine rotation is restored, and the power transmission to the front and rear wheels 4 and 5 and the power transmission to the PTO output shaft are restored. Try to release the brake.

  A front panel 14 on which a meter panel 72 (FIG. 5) for displaying the traveling speed and an operation panel 73 (FIG. 5) for displaying the usage status of the work implement are provided on the front side of the steering handle 8.

  When the throttle lever 15 is erected on the right side of the cockpit 6 and is tilted forward from the foremost idling position, the rotation of the engine 2 increases. The throttle lever 15 is used to set the engine speed during operation. Reference numeral 16 denotes a seesaw-type first engine rotation storage switch. When the switch is tilted upward, the first stored rotational speed is obtained. When the switch is tilted downward, the second stored rotational speed is obtained. When the finger is released, the position returns to the neutral position. Reference numeral 17 denotes a seesaw-type second engine rotation memory switch that has a configuration in which the number of rotations increases when the switch is tilted upward, and the number of rotations decreases when the switch is tilted downward, and the number of rotations when the switch is released is stored.

  The rotation speed of the engine 2 is set by turning the first engine rotation storage switch 16 upward or downward and tilting the second engine rotation storage switch 17 upward or downward to increase or decrease the rotation speed. , 17 is released, the rotation speed at that time is stored as the set rotation speed of the first engine rotation storage switch 16.

  Next to the throttle lever 15, an auxiliary transmission lever 18 is erected. The sub-shift lever 18 has three speeds of low speed, medium speed, and high speed and a shift position for traveling on the road, and the mechanical speed changer in the transmission case 3 is operated at low speed, medium speed, and high speed at three speeds of low speed, medium speed, and high speed. -Shifts at a high speed and the main shift can be shifted to eight stages, and at the road running position, the main gear can be shifted using a gear stage with three or more speeds at a high speed and the speed is suitable for road driving.

  The main shift is a combination of high and low two-speed shifts by hydraulic control, as in the case of four-speed shifts by hydraulic control, and has a total of eight shift stages. The average vehicle speed by these shift stages is the low / medium of the sub-shift lever 18. Combined with high speed and high speed, there are a total of 24 shift stages. The shift stage of the main shift is changed by a travel shift increase switch 33 and a travel shift decrease switch 34 which will be described later.

  Reference numerals 19 and 20 are sub-control levers for taking out external hydraulic pressure, and are used when hydraulic oil is supplied to a hydraulic cylinder or the like of the working machine. 21 and 22 are spare sub-control lever mounting grooves. 23 is a draft ratio adjustment dial, which turns to the left when turned to the position side, reduces the amount of change in the working machine's lifting with respect to the load, reduces the tilling depth, and conversely turns to the right to become the draft side. The amount of change in the lifting and lowering of the work implement with respect to increases the plowing depth.

  Reference numeral 24 denotes a lifting adjustment dial. When the dial 24 is turned counterclockwise, the rising height of the three-point link is lowered. Depending on the working machine, when it is raised to the highest level, when it hits the tractor body or when it is more efficient to continue the work if it is not raised too much, adjustment is made with this raising adjustment dial 24. Reference numeral 25 denotes a tilt adjustment dial. When the dial is turned counterclockwise, the work implement rises to the right.

  26 is a four-WD changeover switch, which has a travel loader, a super full turn, and a two-WD turn position, and the travel loader automatically switches to four WD when it becomes a muddy, steep hill or uneven road, usually with two WD, Even if the brake is applied or stopped during operation, the state becomes four WD. Two-WD is a rear-wheel two-wheel drive, and four-WD is a front-rear four-wheel drive. In the super full turn, the speed of the front wheel is increased by turning at the 4WD, and quick turning is possible, and in the 2WD turn, the driving of the front wheel is removed by turning at the 4WD and the rear wheel is turned by one brake. Quick and smooth turn in hard fields.

  Reference numeral 27 denotes a horizontal cylinder raising / lowering switch which can move the horizontal cylinder of the three-point link and is used for attaching / detaching the work machine. Reference numeral 28 denotes a PTO switch. When the switch is pushed and turned to the right, the PTO clutch is engaged. Reference numeral 29 denotes a PTO automatic switch, which is manually operated when turned to the left and the PTO shaft is always rotated when the PTO clutch is engaged, and is automatically turned when turned to the right and stops rotating when the travel clutch is stepped on or the three-point link is raised. This PTO automatic switch 29 is mainly used during paddy field work.

Reference numeral 30 denotes a diff lock switch. When it is pushed outward once, it becomes diff lock, and when it is pushed outward again, the diff lock is released. It cannot be pushed inward, but switches each time it is pushed outward.
31 is a working machine raising / lowering lever, the front side descends and the rear side rises. Reference numeral 32 denotes a work implement lifting switch, which is raised to the uppermost position set by the raising adjustment dial 24 by pushing the rear side once, and lowered to the position set by the work implement raising / lowering lever 31 when the front side is pushed once.

  Reference numeral 33 denotes a travel shift increase switch, 34 a travel shift decrease switch, and a switch for setting a start shift stage. Each time the travel shift increase switch 33 is pressed once, the start shift stage is shifted up, and the travel shift decrease switch 34 is set to 1. Every time the switch is pressed, the starting gear is shifted down. The travel shift increase switch 33 and the travel shift decrease switch 34 change the start shift stage up and down in the same manner when the sub-shift lever 18 is driven on the road and the sub-shift is at a high speed and the main shift is at the third speed. To do.

  Reference numeral 36 denotes a switch box. When the lid is opened, various adjustment switches shown in FIG. 3 are arranged. In the switch box 36, reference numeral 37 denotes a work machine ascent / descent monitor lamp which is lit and displayed when the work machine is raised and lowered. Reference numeral 38 denotes an AT shift sensitivity dial which changes the sensitivity for increasing or decreasing the vehicle speed when the AT shift work switch 42 is pressed to perform automatic shifting.

  No. 39 is a descent speed dial that adjusts the descent speed of the work implement. When it is turned to the right, the work implement descends quickly, so it is used for light work implements. Conversely, turning it counterclockwise lowers the work implement slowly, so it is heavy. Used for work machines.

Reference numeral 40 denotes a travel brake adjustment dial, which adjusts the degree of application of the turning brake that acts when the auto brake on / off switch 48 is turned on.
The AT shift road switch 41 automatically shifts the main shift when traveling on the road, that is, the sub-shift is at a high speed, and the AT shift work switch 42 automatically shifts the main shift when traveling, that is, the sub-shift is at the middle / low speed, When the switch is turned on, the main shift is automatically shifted to the shift stage that has been used the longest last time according to the shift position of the sub shift lever 18, and when it is turned off, it is arbitrarily set according to the shift position of the sub shift lever 18 The gear shifts to the main gear.

  43 is a connection sensitivity shift switch for the main shift, which changes the connection feeling when the main shift is shifted, and when the switch is turned on, the monitor is turned on and a gentle shift is performed. When the connection sensitivity shift switch 43 is turned off and a traction system such as a plow is operated, the shift connection time of the main transmission is shortened, and the operation can be performed lightly.

  44 is a connection sensitivity PTO switch, which has a rotary, pasture 1 and pasture 2; when it is set to rotary, the connection of PTO becomes faster, and the rotary immediately turns with a rotational force that does not lose the resistance of soil. When it is set to 2, the connection of PTO becomes loose and it is used with pasture work machines and snow blowers.

Reference numeral 45 denotes a horizontal sensitivity switch, which changes the operation sensitivity of the automatic horizontal control device of the work machine.
46 is a backup on / off switch, and when it is turned on, the work machine is automatically raised when the vehicle moves backward. 47 is an auto lift on / off switch, and when it is turned on and the handle is turned, the working machine is automatically raised. 48 is an auto brake on / off switch, and when it is turned on and the handle is turned, only the rear wheel inside the turn is automatically braked.

  49 is a horizontal changeover switch. When the level is automatically leveled, the level of the work machine is automatically maintained by the level sensor. When the level is set manually, the tilt adjustment dial 25 can be adjusted. Is always kept parallel, and when tilted, the three-point link is held at a constant tilt angle with respect to the ground.

  Reference numeral 50 denotes a 3P changeover switch, which performs control changeover selection based on the lift cylinder mounting position to the three-point link. Reference numeral 51 denotes an auto accelerator switch. When the work machine is raised in the on state, the engine speed decreases to 1700 rpm.

FIG. 4 is a diagram showing a driving force transmission mechanism, and a power transmission configuration from the engine 2 to the front wheels 4 and the rear wheels 5 will be described.
A first gear 111 is fixed to an input shaft 110 directly connected to an output shaft of the engine 2 and a forward / reverse switching clutch 101 is mounted. One second gear 112 of the forward / reverse switching clutch 101 meshes with a third gear 114 fixed to the first transmission shaft 113 and decelerates, and the other fourth gear 115 of the forward / reverse switching clutch 101 is connected via a counter gear 117. The power is transmitted in reverse by meshing with the fifth gear 118 fixed to the first transmission shaft 113.

  That is, when the forward / reverse switching clutch 101 is placed (connected) on the second gear 112 side, the rotation of the input shaft 110 is transmitted in the reverse direction to the first transmission shaft 113, and when it is placed on the fourth gear 115 side, The rotation is transmitted to the first transmission shaft 113 in the forward direction, and the neutral state away from both the second gear 112 and the fourth gear 115 is the main clutch disengaged state where the power transmission is cut off. The clutch disengaged state can be maintained. That is, the forward / reverse switching clutch 101 operated by automatic control or the forward / reverse lever 9 functions as a main clutch.

  A first speed / three-speed switching first transmission clutch 102 and a second speed / four-speed switching second transmission clutch 103 are mounted on the first transmission shaft 113 on the lower transmission side of the forward / reverse switching clutch 101. The first speed / third speed switching first speed change clutch 102 and the second speed / fourth speed speed changing second speed clutch 103 are shifted by a travel speed change switch 33 and a travel speed change switch 34.

  The first clutch gear 120 and the second clutch gear 122 of the first transmission clutch 102 are engaged with a third clutch gear 121 and a fourth clutch gear 123 fixed to the second counter shaft 119, and are decelerated for the first speed or for the third speed. The rotation of the first transmission shaft 113 is transmitted to the second counter shaft 119 with a slight increase in speed. Further, the fifth clutch gear 124 and the sixth clutch gear 126 of the second transmission clutch 103 are engaged with the seventh clutch gear 125 and the eighth clutch gear 127 fixed to the second counter shaft 119, and are slightly increased for the second speed. The speed of the first speed change shaft 113 is transmitted to the second countershaft 119 by greatly increasing the speed for the fourth speed.

  A third counter shaft 129 is connected to the lower transmission side of the second counter shaft 119 by a coupling 128 to transmit the rotation as it is. A small gear 130 and a large gear 131 are fixed to the third counter shaft 129. The small gear 130 and the large gear 131 are engaged with the clutch large gear 133 and the clutch small gear 134 of the high / low speed switching clutch 107 mounted on the second transmission shaft 132, respectively, and the third counter shaft 129 rotates at a high speed or a low speed. It is transmitted to the two speed change shaft 132. A high / low speed switching clutch 107 that is automatically controlled or operated by a high / low speed shift lever 109 functions as a sub-clutch of the present invention.

  The sixth gear 136 is fixed to the lower transmission side end portion of the second transmission shaft 132, and the sixth gear 136 and the large gear portion 138 of the large and small gear 152 pivotally supported by the third drive shaft 143 are engaged with each other. Is decelerating.

  The small gear portion 139 of the large and small gears 152 meshes with the seventh gear 137 of the double auxiliary transmission clutch 135 that is pivotally supported by the bevel gear shaft 142 and is transmitted at a reduced speed. Further, the eighth gear 141 provided integrally with the seventh gear 137 is engaged with the second large gear 144 fixed to the fifth counter shaft 216 for transmission at a reduced speed.

  A second small gear 145 is further fixed to the fifth counter shaft 216, and the second small gear 145 meshes with the third large gear 140 of the bevel gear shaft 142 to further reduce the transmission. Accordingly, the rotation of the second transmission shaft 132 is the sixth gear 136 → the large gear portion 138 → the small gear portion 139 → the seventh gear 137 → the eighth gear 141 → the second large gear 144 → the second small gear 145 → the third large gear. The gear 140 is transmitted while being sequentially decelerated.

  The first shifter 217 and the second shifter 218 of the double sub-shift clutch 135 operated by the auxiliary transmission lever 18 are slidably engaged with the bevel gear shaft 142 in the axial direction, and the first shifter 217 is engaged with the seventh gear 137. When the second shifter 218 slides and engages with the eighth gear 141, the rotation of the eighth gear 141 is transmitted to the bevel gear shaft 142. Accordingly, the bevel gear shaft 142 is sequentially decelerated and rotates at a low speed.

  The rotation of the bevel gear shaft 142 is transmitted to the differential gear 219 via the first bevel gear 148 and the second bevel gear 149, and is transmitted from the differential gear 219 to the rear wheel 5 via the axle 150 and the planetary gear 151.

  To summarize the above description, the rotation of the input shaft 110 is first switched to forward rotation or reverse rotation by the forward / reverse switching clutch 101, and the first speed / three-speed switching first shift clutch 102 and the second / fourth-speed switching first gear 102 are switched. The speed is changed from the first speed to the fourth speed by the two speed clutch 103, the speed is changed to the high speed and the low speed by the high / low speed switching clutch 107, and the high speed, the middle speed and the low speed are further increased by the double sub-shift clutch 135. And is transmitted to the bevel gear shaft 142. That is, the rotation of the input shaft 110 is shifted to 4 × 2 × 3 = 24 speeds and transmitted to the axle 150.

  For driving force transmission to the front wheel 4, the ninth gear 147 is fixed to the bevel gear shaft 142, the ninth gear 147 is meshed with the relay gear 190, and further meshed with the tenth gear 146 fixed to the third drive shaft 143. The third drive shaft 143 is driven. The third drive shaft 143 is connected by a second coupling 170 to a transmission shaft 160 to which a front wheel speed increasing clutch 163 is attached. The eleventh gear 167 and the twelfth gear 168 of the front wheel speed increasing clutch 163 are engaged with the thirteenth gear 165 and the fourteenth gear 166 fixed to the seventh counter shaft 164, so that the front wheel speed increases from the normal front wheel drive. To switch to. When the front wheel acceleration clutch 163 is neutral, the driving of the front wheels 4 is cut off and only the rear wheels are driven.

  The seventh counter shaft 164 is connected to the front wheel drive shaft 169 by a third coupling 191, and is further connected to the front wheel drive bevel shaft 171 by a fourth coupling 192, an extension shaft 194 and a fifth coupling 193.

  The power of the front wheel drive bevel shaft 171 is as follows: front first bevel gear 172, front second bevel gear 173, front differential gear 174, front third bevel gear 175, front fourth bevel gear 176, vertical shaft 177, front fifth bevel gear 178, front sixth The front wheel 4 is driven via the bevel gear 179 and the front planetary gear 180.

Next, the flow of the control signal will be described with reference to the control block diagram of FIG.
First, a mode signal is input to the engine controller 60 from an engine mode selection switch 97 that selects the travel mode A, the normal work mode B, and the heavy work mode C, and the exhaust gas temperature is input from the engine exhaust temperature sensor 61. The engine speed is input from the sensor 62, the pressure of the engine lubricating oil is input from the engine oil pressure sensor 63, the temperature of the cooling water is input from the engine water temperature sensor 64, the pressure of the common rail is input from the rail pressure sensor 55, and the auto accelerator switch 51 , The energy saving or power operation mode is entered, the output speed of the output shaft is entered from the engine revolution sensor 62 of the engine 2, and the output torque is entered from the output torque sensor 100.

From the engine controller 60, a drive signal is output to the high-pressure fuel pump 66, and a fuel supply adjustment control signal is output to the high-pressure injector 65.
The energy saving mode S switched by the auto accelerator switch 51 is an output torque mode in which the fuel supply is reduced in the travel mode A, the normal work mode B, and the heavy work mode C, as shown in FIG. Thus, the driving torque is lower than that in the normal power mode P.

  The engine controller 60 calculates the ratio of the output torque for each mode to the theoretical output torque as the engine load factor in the operating mode (power mode P or energy saving mode S).

  It is also possible to determine the traveling state and automatically change to the energy saving mode S when the vehicle is in steady traveling so that the vehicle can travel with as low fuel consumption as possible. The determination of steady running is made when there is little change in the operation of the accelerator pedal 13 and the load factor is within the specified range or the engine speed is within the specified range.

  The auto accelerator switch 51 switches to the power mode P or the energy saving mode S. When the engine load factor is lower than the specified load factor during operation in the power mode P, the auto accelerator switch 51 automatically switches to the energy saving mode S. When the engine load factor becomes higher than the specified load factor during operation in the energy saving mode S, the mode is automatically switched to the power mode P.

  In addition, as will be described in detail later, when the work implement is raised, it automatically switches to the energy saving mode S, and when the work implement is lowered, it switches to the original setting operation mode, thereby improving the fuel efficiency when not working. Plan.

  The engine controller 60 of the diesel engine 2 having a common rail has three kinds of control modes of a traveling mode A, a normal working mode B, and a heavy working mode C that are switched by the engine mode selection switch 97 in the relationship between the rotational speed and the output torque. It is configured.

  The traveling mode A is droop control in which the output also varies with the variation of the engine speed. It is used when traveling without farming. For example, when the traveling speed is reduced or stopped by applying a brake, the engine speed decreases with an increase in the traveling load, so that the traveling speed can be safely reduced or stopped.

  The normal work mode B is isochronous control in which the engine speed is constant and the output is changed according to the load even when the load varies. It is used for normal farm work. For example, when cultivated land is hard during plowing work and resistance is applied to the plowing blade, and when the output fluctuates and the rotation speed is maintained.

  In the heavy work mode C, in addition to the isochronous control in which the engine speed is constant and the output is changed according to the load even when the load fluctuates in the same manner as the normal work mode B, the engine speed is increased when the load is close to the limit. This is a control with heavy load control that increases In particular, it is used when farming near the load limit. For example, when plowing work with a tractor, the engine output increases beyond the normal limit even when encountering hard cultivated land, so work can be done efficiently without interruption. Become.

  The work implement lift controller 67 includes an operation signal of the work implement lift sensor 59 provided on the work implement lift lever 31, a lift signal of the lift arm sensor 68, a lift position restriction signal of the lift adjustment dial 24, and a drop speed of the drop speed adjustment dial 39. Each of the setting signals is input, and a work implement lift signal is output to the main lift solenoid 69 and the main drop solenoid 70 to operate the work lift cylinder 71.

  The engine controller 60, the work implement elevating controller 67, and a travel system controller 87, which will be described later, communicate with each other, and the engine panel, the elevating state of the work implement, the travel speed of the travel device, and the like are displayed on the meter panel 72. The operation position of each lever and pedal is displayed on the panel 73.

  The travel system controller 87 receives a clutch engagement signal, that is, a gear position from the transmission 1 clutch pressure sensor 74, the transmission 2 clutch pressure sensor 75, the transmission 3 clutch pressure sensor 76, and the transmission 4 clutch pressure sensor 77, and A shift position is input from the low speed clutch pressure sensor 79, and forward / neutral / reverse of the main clutch B is input from the forward clutch pressure sensor 80 and the reverse clutch pressure sensor 81.

  A shift operation position signal is input from the forward / reverse lever operation position sensor 82 and the sub-shift lever operation position sensor 83, the mission oil temperature is input from the mission oil temperature sensor 85, and the brake pedal is depressed from the brake pedal operation position sensor 86. A signal is inputted, a mode switching signal is inputted from the engine power selection switch 84, a set gear stage signal is inputted from the traveling shift increase switch 33 and the traveling shift decrease switch 34, and the upper and lower limit rotations of the engine are transmitted from the accelerator shift setting switch 52. A number is input, and an accelerator instruction signal is input from the accelerator sensor 54 of the throttle lever 15.

  Further, a shift signal is input to the traveling system controller 87 from the AT shift road switch 41 and the AT shift work switch 42. As for the output from the traveling system controller 87, a switching signal for the forward / reverse switching clutch 101 is output to the forward / reverse switching solenoid 88, and a hydraulic relief pressure adjustment signal for driving the forward / reverse switching solenoid 88 is output to the linear boost solenoid 89. The clutch engagement shock is reduced, an on / off signal is output to the clutch solenoid 90, and the first to third switching solenoid 91 of the hydraulic cylinder that drives the first speed / three-speed switching first shift clutch 102 is driven to the first or third speed. A fast input signal is output.

  A hydraulic relief pressure adjustment signal for driving the 1st / 3rd speed clutch is output to the 1st-3 step-up solenoid 92 to reduce the shock of clutch connection, and the 2nd speed / fourth speed switching second speed change clutch 103 is driven. A second-speed or fourth-speed input signal is output to the shift 2-4 switching solenoid 93 of the hydraulic cylinder, and a hydraulic relief pressure adjustment signal for driving the second-speed / four-speed clutch is output to the shift 2-4 boost solenoid 94. The high-speed clutch input signal and the low-speed clutch input signal are output to the high-speed clutch switching solenoid 95 and the low-speed clutch switching solenoid 96 that operate the hydraulic cylinder that drives the high / low speed switching clutch 107 to reduce the shock of clutch connection.

  FIG. 7 is an automatic control flowchart for automatically switching between the energy saving mode S for reducing the fuel consumption rate and the power mode P for maximizing the output torque in the traveling mode A, the normal working mode B, and the heavy working mode C. Control is performed by turning on the switch 51.

In step S1, each sensor and operation switches are read, and in step S2, an engine control mode by the auto accelerator switch 51 is determined.
If it is the energy saving mode S, the on / off state of the PTO switch 28 is determined in step S3, and if it is on (YES), the traveling mode A (droop control) is performed in the energy saving S in step S4 and the process returns.

  If the determination in step S3 is OFF (NO), the travel mode A (droop control) is performed in step S5, the accelerator shift is determined in step S6, and if the shift is not in progress (NO), the process returns as it is. If it is medium (YES), it is determined during the acceleration operation in step S7, and if it is during the acceleration operation (YES), the normal operation mode B (isochronous control) in the power mode P is performed in step S8 and the process returns. If the acceleration operation is not in progress (NO), the routine proceeds to the determination of steady operation in step S9.

  If the determination in step S9 is steady operation (YES), control is returned in the driving mode A (droop control) in step S10, and if it is not steady operation (NO), the operation mode is determined again in step S11. If it is energy saving mode S, it will transfer to step S10, and it will control and return by driving mode A (droop control) by energy saving, and if it is power mode P, it will be controlled by driving mode A (droop control) and return in step S12. To do.

  If it is determined in step S2 that the power mode is P, it is determined in step S13 that the PTO switch 28 is turned on. If the switch is turned on (YES), the normal operation mode B (isochronous control) in the power mode P is executed in step S14. If the control is returned and the switch is turned off (NO), the control is performed in the driving mode A (droop control) in the power mode P in step S15, and the process proceeds to the determination in step S6.

FIG. 8 is a flowchart of automatic control in which the auto accelerator switch 51 is turned on and the power mode P and the energy saving mode S are automatically selected as the work implement is moved up and down.
In step S20, each sensor and operation switches are read. In step S21, it is determined whether the currently selected engine control mode is power mode P. If the determination is not power mode P (NO), energy saving is performed in step S35. Select mode S and return. If the determination in step S21 is the power mode P (YES), it is determined in step S22 whether the load factor is 80% or less. If the determination is (YES) below, the energy saving mode S is selected in step S23. If the determination is 80% or more (NO), the power mode P is selected in step S24, and it is determined whether the work implement raising operation is being performed in step S25.

  If the lifting / lowering signal from the lift arm sensor 68 determines that the work implement raising (lowering) operation is being performed, and the determination in step S25 is that the work implement raising operation is being performed (YES), the engine rotation speed is reduced to the specified rotation speed in step S26. In step S27, the droop control in the energy saving mode S is selected and the process returns.

  If the determination in step S25 is not during the work implement raising operation (NO), the reverse determination of the forward / reverse lever 9 is performed in step S28, and if reverse (YES), the process proceeds to step S26 and is not reverse (NO). ), The process proceeds to step S29 to determine whether the work implement is being lowered. If the determination that the work implement lowering operation is being performed in step S29 is a lowering operation (YES), the process proceeds to step S30, and if the lowering operation is not being performed (NO), the process returns.

  Further, in step S30, it is determined whether the power mode P was immediately before the raising operation. If the power mode P (YES), isochronous control in the power mode P is selected in step S31, and it is determined in step S32 that both brakes are being operated. If the determination is that both brakes are not being operated (NO), it is determined in step S33 whether the sub-shift position is traveling on the road. If the determination is not on the road (NO), the engine speed is restored in step S34 and the process returns.

  If the determination in step S30 is NO, the determination in step S32 is YES, or if the determination in step S33 is YES, the process proceeds to step S26, where the engine speed is reduced to the specified speed, and in step S27. Select energy saving mode S and return.

  The automatic control described above is a control in the case where the auto accelerator switch 51 is switched to save energy. When the auto accelerator switch 51 is switched to power at any stage of the control, switching to the energy saving mode S is not performed.

The tractor 1 shown in FIG. 9 and FIG. 10 is an electric tractor having the same basic configuration as that of a conventional tractor and driving each rotating part by a motor.
In contrast to a single front wheel drive motor 223 that drives the left and right front wheels 4, 4 and a transmission case 224 that outputs driving force to the left and right rear wheels 5, 5 and the PTO shaft 227, a small first motor 221 and a large first The two motors 222 are mounted, and a lifting motor 225 is mounted for lifting and lowering a three-point link for mounting the work machine. Each motor 221, 222, 223, 225 is supplied with electric power from a battery 220 mounted in the hood 226.

  The front wheel drive motor 223, the first motor 221 and the second motor 222 are attached to the vehicle body below the floor of the cabin 7. The large second motor 222 is located at the center of the left and right rear wheels 5, 5.

  The front wheel drive motor 223 is configured to send regenerative power to the battery 220 as a generator in a state where travel resistance is not so much when driving with two WDs. Further, the front wheel drive motor 223, the first motor 221 and the second motor 222 are configured to send regenerative power to the battery 220 as a generator during downhill traveling and traveling braking. The first motor 221 and the second motor 222 send regenerative power to the battery 220 even when the rotation of the PTO shaft 227 is stopped.

  The first motor 221 and the second motor 222 mounted on the mission case 224 share the traction and the drive of the PTO shaft 227 via the mission case 224 that performs drive switching with a hydraulic clutch, so that a large driving force depends on the working state. The large-sized second motor 222 shares the drive on the side that requires the motor. For example, when the traction switch is pressed, the second motor 222 shares the traveling drive. In addition, in the case where the tow is performed solely even when the PTO switch is turned off, the small first motor 221 also assists the traveling drive.

2 Engine 68 Elevation detection means (lift arm sensor)
97 Engine mode selection means P Power mode S Energy saving mode

Claims (2)

  A plurality of output modes of the engine (2) and an engine mode selection means (97) for selecting the output mode of the engine (2) are provided, and a lift detection means (68) for detecting the lift of the work implement mounted on the work vehicle. When the elevating detection means (68) detects an increase in work while driving with the engine mode selection means (97) selecting the power mode (P), the engine output mode is switched to the energy saving mode (S). An engine control device for a work vehicle, wherein the engine output mode is switched to a power mode (P) when the lift detection means (68) detects the lowering of the work implement.   An isochronous mode that maintains constant rotation of the engine (2) and a droop mode in which the rotation fluctuates according to the load are provided. When the work equipment rises during operation in isochronous mode, it switches to droop mode, and when the work equipment descends, isochronous The engine control device for a work vehicle according to claim 1, wherein the engine control device is configured to return to the mode.

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