WO2011108444A1 - Engine control device and engine control method for working vehicle - Google Patents

Engine control device and engine control method for working vehicle Download PDF

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Publication number
WO2011108444A1
WO2011108444A1 PCT/JP2011/054198 JP2011054198W WO2011108444A1 WO 2011108444 A1 WO2011108444 A1 WO 2011108444A1 JP 2011054198 W JP2011054198 W JP 2011054198W WO 2011108444 A1 WO2011108444 A1 WO 2011108444A1
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WO
WIPO (PCT)
Prior art keywords
engine
engine speed
output torque
value
work vehicle
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PCT/JP2011/054198
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French (fr)
Japanese (ja)
Inventor
芳明 齋藤
周 武田
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株式会社小松製作所
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Application filed by 株式会社小松製作所 filed Critical 株式会社小松製作所
Publication of WO2011108444A1 publication Critical patent/WO2011108444A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/0205—Circuit arrangements for generating control signals using an auxiliary engine speed control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2250/00—Engine control related to specific problems or objectives
    • F02D2250/18—Control of the engine output torque
    • F02D2250/26—Control of the engine output torque by applying a torque limit
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D31/00—Use of speed-sensing governors to control combustion engines, not otherwise provided for
    • F02D31/001—Electric control of rotation speed
    • F02D31/007—Electric control of rotation speed controlling fuel supply

Definitions

  • the present invention relates to an engine control device and an engine control method for a work vehicle.
  • Construction machines such as wheel loaders operate a work machine by rotating a variable displacement hydraulic pump connected to an output rotation shaft of an engine and driving a hydraulic actuator by pressure oil discharged from the hydraulic pump. .
  • the engine speed does not fluctuate greatly due to fluctuations in the work load so that the hydraulic actuator is stably driven regardless of the work load.
  • construction machinery employs an all-speed governor in which fluctuations in engine speed with respect to fluctuations in work load are small as an electronic governor that electrically controls the fuel injection amount of the engine.
  • FIG. 8 is a diagram showing the relationship between the engine speed and the engine output torque when the fuel injection amount of the engine is controlled by the all speed governor when the construction machine is running stably.
  • the stable running means that the construction machine is running in a state where the engine speed within a predetermined time is within a predetermined range.
  • symbol AL indicates an absorption torque curve of a traveling system for traveling a construction machine
  • symbol RL indicates a regulation line that determines the upper limit of the engine output corresponding to the accelerator pedal operation amount of the operator.
  • FIG. 9 is a diagram showing a change over time in the fuel injection amount when the fuel injection amount of the engine is controlled by the all speed governor when the construction machine is running stably.
  • the engine output is controlled so that the absorption torque absorbed by the traveling system matches the engine output.
  • the absorption torque absorbed by the traveling system changes as shown by a curve AL shown in FIG. 8 at a certain speed ratio of the torque converter.
  • the speed ratio is low during acceleration immediately after the construction machine starts, and is high during stable running.
  • a curve AL ′ in FIG. 8 indicates the absorption torque during acceleration, and is, for example, a speed ratio of 0.3.
  • a curve AL in FIG. 8 indicates the absorption torque during stable running, and is, for example, 0.8 in speed ratio. As the speed ratio increases, the curve AL ′ moves from the high torque side to the low torque side to become the curve AL.
  • the absorption torque absorbed by the traveling system is large during acceleration and gradually decreases.
  • the absorbed torque absorbed by the traveling system is substantially constant at a low value during stable traveling. For this reason, the engine speed at which the engine can output the absorption torque absorbed by the traveling system is constant on the regulation line RL.
  • the intersection of the absorption torque curve AL and the regulation line RL is called a matching point.
  • the engine speed is within a predetermined range ⁇ R centering on the engine speed R0 corresponding to the matching point M between the absorption torque curve AL and the regulation line RL of the traveling system.
  • the all speed governor increases or decreases the fuel injection amount with respect to the fuel injection amount F 0 corresponding to the engine speed R 0 , as shown in FIG. Let That is, when the load increases and the engine speed decreases, the all speed governor increases the fuel injection amount according to the regulation line RL so that an output that matches the decreased engine speed is generated.
  • the all speed governor decreases the fuel injection amount according to the regulation line RL. That is, in the all speed governor, even when the construction machine is running stably and the engine speed is not set to the target speed, the engine output torque along the regulation line RL as shown in FIG. Increase or decrease the engine output torque within the range of T max to T min .
  • the regulation line RL exists for each accelerator opening, a matching point also exists for each accelerator opening.
  • the present invention has been made in view of the above, and an object thereof is to provide an engine control device and an engine control method for a work vehicle that can reduce fuel consumption during stable running.
  • an engine control device for a work vehicle is an engine control device for a work vehicle that controls the fuel injection amount of the engine with an all-speed governor, and the engine speed is Based on the engine speed detected by the engine speed detecting means and the engine speed detected by the engine speed detecting means, it is determined whether or not the fluctuation of the engine speed within a predetermined time is within a predetermined range.
  • the determination means for determining that the work vehicle is in a stable running state and the determination means determine that the work vehicle is in a stable running state, and detecting the engine speed
  • the engine speed detected by the means is below a predetermined value, the engine fuel is limited so as to limit the engine output torque.
  • a control means for controlling the injection amount, the.
  • an engine control method for a work vehicle is an engine control method for a work vehicle that controls the fuel injection amount of the engine by an all-speed governor, the engine speed being Based on the detection step for detecting the engine speed and the engine speed detected in the detection step, it is determined whether or not the fluctuation of the engine speed within a predetermined time is within a predetermined range, and the engine speed within the predetermined time is determined.
  • a determination step for determining that the work vehicle is in a stable running state and a determination step determines that the work vehicle is in a stable running state, and the engine speed detected in the detection step is predetermined. If the value is less than the value, a control step for controlling the fuel injection amount of the engine so as to limit the engine output torque. And, including the.
  • the engine control device and the engine control method for a work vehicle since the output torque of the engine is limited at the time of stable traveling, it is possible to suppress wasteful consumption of fuel at the time of stable traveling, Fuel consumption can be reduced.
  • FIG. 1 is a schematic side view showing the overall configuration of a wheel loader according to an embodiment of the present invention.
  • FIG. 2 is a block diagram showing a configuration of an engine control device that controls the operation of the engine of the wheel loader shown in FIG.
  • FIG. 3 is a flowchart showing a flow of engine control processing by the engine control apparatus shown in FIG.
  • FIG. 4 is a diagram illustrating an example of an engine output torque limit line map.
  • FIG. 5 is a diagram for explaining the engine control process when the engine speed is within a predetermined range.
  • FIG. 6 is a diagram for explaining the engine control process when the engine speed is out of the predetermined range.
  • FIG. 7 is a diagram showing a change with time of the fuel injection amount by the engine control process shown in FIG. FIG.
  • FIG. 8 is a diagram showing the relationship between the engine speed and the output torque when the fuel injection amount of the engine is controlled by the all speed governor when the construction machine is running stably.
  • FIG. 9 is a diagram illustrating a change over time in the fuel injection amount when the fuel injection amount of the engine is controlled by the all speed governor when the construction machine is running stably.
  • FIG. 10 is a flowchart showing a modification of the engine control process shown in FIG.
  • FIG. 1 is a schematic side view showing the overall configuration of a wheel loader according to an embodiment of the present invention.
  • a wheel loader 1 according to an embodiment of the present invention includes a work machine 2, a frame unit 3, and a vehicle body 4.
  • the work machine 2 includes a lift arm 5.
  • the lift arm 5 is attached to the frame portion 3 with a base end portion freely swingable.
  • the frame portion 3 and the lift arm 5 are connected by a pair of lift cylinders 6.
  • the lift arm 5 swings as the lift cylinder 6 expands and contracts according to the operation of the work implement lever by the operator.
  • the bucket 7 is attached to the tip of the lift arm 5 and the bell crank (tilt lever) 8 is swingably attached to the substantially central part.
  • One end portion of the bell crank 8 and the frame portion 3 are connected by a tilt cylinder 9.
  • the other end of the bell crank 8 and the bucket 7 are connected by a tilt rod 10.
  • the bucket 7 swings as the tilt cylinder 9 expands and contracts according to the operation of the work implement lever by the operator.
  • the vehicle body 4 is equipped with a traveling device for traveling the wheel loader 1 and an engine 11 for supplying drive output to the traveling device.
  • the traveling device includes a PTO mechanism 12, a torque converter (T / C) 13, a transmission 14 that can be switched forward and backward and a plurality of shift speeds, a transfer 15, and a speed reducer 18 that drives a front wheel 16 and a rear wheel 17. Is provided.
  • the drive output of the engine 11 is transmitted to the transfer 15 via the PTO mechanism 12, the T / C 13, and the transmission 14 in order, and is transmitted to the speed reducer 18 on the front wheel 16 and rear wheel 17 side by the transfer 15.
  • the speed reducer 18 transmits the driving output of the engine 11 transmitted by the transfer 15 to the front wheels 16 and the rear wheels 17.
  • the vehicle body 4 is equipped with a variable displacement hydraulic pump 20 that supplies pressure oil to the lift cylinder 6 and the tilt cylinder 9 via a work machine control valve (not shown).
  • the hydraulic pump 20 is connected to the engine 11 via the PTO mechanism 12 and is driven using a part of the drive output of the engine 11.
  • the pump capacity of the hydraulic pump 20 is variably controlled by changing the inclination angle of the swash plate of the hydraulic pump 20 by a controller (not shown).
  • a driver's cab 21 is provided in the upper part of the vehicle body 4.
  • a driving operation device 22 including a transmission shift lever, an accelerator pedal, a brake pedal, and a work implement lever for operating the work implement 2 operated by the driver is provided in the cab 21.
  • the driver can operate the driving operation device 22 to perform forward / reverse switching of the wheel loader 1, adjustment of traveling speed (acceleration and deceleration), and operation of the work machine 2.
  • FIG. 2 is a block diagram showing a configuration of an engine control device that controls the operation of the engine 11 of the wheel loader 1 shown in FIG.
  • the engine control apparatus 100 includes an engine speed sensor 101, an engine output torque sensor 102, a speed stage sensor 103, a work implement lever sensor 104, an accelerator pedal sensor 105, a transmission controller 106, an engine controller 107, and A work machine controller 111 is provided.
  • the engine rotation speed sensor 101 is attached to the output rotation shaft of the engine 11 and detects the rotation speed of the engine 11.
  • the engine speed sensor 101 inputs an electric signal indicating the speed of the engine 11 to the transmission controller 106.
  • the engine speed sensor 101 functions as engine speed detection means according to the present invention.
  • the engine output torque sensor 102 is attached to the output rotation shaft of the engine 11 and detects the output torque of the engine 11.
  • the engine output torque sensor 102 inputs an electric signal indicating the output torque of the engine 11 to the transmission controller 106.
  • the speed stage sensor 103 detects the position of the speed stage lever 108 for switching the speed stage of the wheel loader 1 and inputs an electric signal indicating the detected position to the transmission controller 106.
  • the work implement lever sensor 104 detects an operation amount of the work implement lever 109 for operating the lift cylinder 6 and the tilt cylinder 9 and inputs an electric signal indicating the detected operation amount to the work implement controller 111.
  • the work machine controller 111 controls the transmission controller 106 and the engine controller 107 based on the electrical signal input from the work machine lever sensor 104.
  • the accelerator pedal sensor 105 detects an operation amount of the accelerator pedal 110 and inputs an electric signal indicating the detected operation amount to the transmission controller 106.
  • the transmission controller 106 is realized by a microcomputer including a CPU, a RAM, a ROM, an input / output circuit, and the like.
  • a control program and an engine output torque limit line map indicating the relationship between the engine speed and the engine output torque limit value are stored in advance. Details of the engine output torque limit line map will be described later.
  • the CPU in the transmission controller 106 loads the control program into the RAM, and executes the control program loaded into the RAM, whereby the engine speed sensor 101, the engine output torque sensor 102, the speed stage sensor 103, the accelerator pedal.
  • a control signal for controlling the operation of the engine 11 is output to the engine controller 107 in accordance with an electrical signal input from the sensor 105 and the work machine controller 111.
  • the transmission controller 106 functions as determination means and control means according to the present invention.
  • the engine controller 107 is realized by a microcomputer including a CPU, a RAM, a ROM, an input / output circuit, and the like.
  • a control program is stored in advance in the engine controller 107.
  • the CPU in the engine controller 107 loads the control program into the RAM, and executes the control program loaded into the RAM, so that the engine 11 operates in accordance with control signals input from the transmission controller 106 and the work machine controller 111. Control the behavior. Specifically, the CPU in the engine controller 107 controls the operation of the all speed governor 11 a that controls the fuel injection amount of the engine 11 in accordance with a control signal input from the transmission controller 106.
  • the transmission controller 106 and the engine controller 107 are configured separately, but the transmission controller 106 and the engine controller 107 may be configured integrally.
  • the control program and engine output torque limit line map stored in the transmission controller 106 and engine controller 107 are files in an installable or executable format, such as CD-ROM, flexible disk, CD-R, DVD, etc. It may be configured to be recorded and provided on a computer-readable recording medium.
  • the control program and the engine output torque limit line map may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Further, the control program and the engine output torque limit line map may be provided or distributed through a telecommunication line such as the Internet.
  • the controller to which electrical signals from various sensors are input is an example, and the electrical signals from various sensors may be input to controllers other than those described above.
  • the engine output torque is detected by the engine output torque sensor 102.
  • the engine output torque may be obtained by calculation from the engine speed, the fuel injection amount, the atmospheric pressure, or the like.
  • FIG. 3 is a flowchart showing the flow of engine control processing by the engine control apparatus 100.
  • the engine control process by the engine control device 100 starts at the timing when the ignition switch of the wheel loader 1 is switched from the off state to the on state, and proceeds to the process of step S1.
  • step S1 the transmission controller 106 detects the engine speed and the engine output torque using the engine speed sensor 101 and the engine output torque sensor 102, and detects them within a predetermined time (for example, 5 seconds). The stored engine speed and engine output torque are temporarily stored. Thereby, the process of step S1 is completed and the engine control process proceeds to the process of step S2.
  • the transmission controller 106 determines whether or not the wheel loader 1 is in a stable travel state based on the engine speed stored in the process of step S1. Specifically, the transmission controller 106 determines whether or not the fluctuation of the engine speed within a predetermined time is within a predetermined range. Note that the value of the predetermined time is about 5 [sec] in order to reliably detect that the wheel loader 1 is in a stable running state and suppress occurrence of hunting in which engine control is frequently switched. It is desirable to set.
  • the value in the predetermined range is a value set in advance in consideration of the fluctuation value of the engine speed that may be caused by the fluctuation of the traveling load when the wheel loader 1 is traveling on the road surface. That is, the engine speed varies due to some unevenness on the road surface. Therefore, it is desirable that the value in the predetermined range is a value that does not cause frequent switching of engine control even under the influence of road surface unevenness. Specifically, the value in the predetermined range is a value of about 10 [rpm].
  • the transmission controller 106 determines that the wheel loader 1 is in a stable running state, and advances the engine control process to the process of step S3.
  • the transmission controller 106 determines that the wheel loader 1 is not in a stable running state, and returns the engine control process to the process of step S1.
  • step S3 the transmission controller 106 stores the maximum value N_eng_max and the minimum value N_eng_min of the engine speed among the engine speeds stored in the process of step S1 in the storage unit 106a. Thereby, the process of step S3 is completed and the engine control process proceeds to the process of step S4.
  • step S4 the transmission controller 106 calculates the average value N_eng_ave of the engine speed and the average value T_eng_ave of the engine output torque within the predetermined time stored by the process of step S1, and the calculated engine speed.
  • the average value N_eng_ave and the average value T_eng_ave of the engine output torque are stored in the storage unit 106a.
  • step S5 the transmission controller 106 detects the engine speed using the engine speed sensor 101, and the detected engine speed is an average value N_eng_ave of the engine speeds calculated by the process of step S4. It is determined whether or not: As a result of the determination, if the engine speed is equal to or lower than the average engine speed N_eng_ave, the transmission controller 106 advances the engine control process to the process of step S6. On the other hand, when the engine speed is larger than the average engine speed N_eng_ave, the transmission controller 106 advances the engine control process to step S7.
  • the transmission controller 106 detects the engine speed detected by the process of step S5 based on the average value N_eng_ave of the engine speed calculated by the process of step S4 and the average value T_eng_ave of the engine output torque.
  • the engine output torque limit value corresponding to is calculated, and the calculated engine output torque limit value is output to the engine controller 107 as an engine output torque command value.
  • the engine controller 107 controls the all speed governor 11a according to the engine output torque command value, and the all speed governor 11a controls the fuel injection amount of the engine 11 so as to output the engine output torque corresponding to the engine output torque limit value.
  • FIG. 4 is a diagram illustrating an example of an engine output torque limit line map stored in advance in the storage unit 106 a of the transmission controller 106.
  • the engine output torque limit line map shows engine output torque limit lines LL1 to LL1 indicating the relationship between the engine speed and the engine output torque for each of a plurality of engine output torque ratios, with the maximum output torque being 100%. It is configured by LL6.
  • the value of the engine output torque ratio shown in FIG. 4 does not indicate a strict ratio with respect to the maximum output torque. That is, the value of the engine output torque ratio is quantified for convenience in order to reduce the engine output torque to some extent, that is, to limit the fuel injection amount.
  • the transmission controller 106 controls the output torque of the engine 11 according to the engine output torque limit line LL2. That is, the transmission controller 106 controls the fuel injection amount so as not to exceed the engine output torque limit line LL2.
  • the transmission controller 106 outputs the output torque of the engine 11 according to the engine output torque limit line LL6.
  • a curve RL1 indicates a regulation line when the throttle opening is 0 [%].
  • an engine output torque limit line corresponding to an unspecified engine output torque ratio between engine output torque ratios defined in the engine output torque limit line map shown in FIG. 4 is obtained by interpolation processing. Specifically, when obtaining an engine output torque limit line having an engine output torque ratio of 50%, the transmission controller 106 sets the engine output torque limit line LL3 corresponding to the engine output torque ratio 40% and the engine output torque ratio 60%. An engine output torque limit line having an engine output torque ratio of 50% is obtained by interpolation using the corresponding engine output torque limit line LL4. Further, the engine output torque limit line may be horizontal without an inclination as shown in FIG. That is, the engine output torque limit line only needs to be configured to suppress a rapid decrease in the engine speed due to an increase in load, and may be a curved line instead of a straight line as shown in FIG.
  • the transmission controller 106 calculates an engine output torque limit line LL that passes through the coordinate values (N_eng_ave, T_eng_ave) from the engine output torque limit line map. Then, the transmission controller 106 specifies the position on the engine output torque limit line LL corresponding to the engine speed detected by the process of step S5, and calculates the engine output torque at the specified position as the engine output torque limit value. . As a result, the output torque of the engine 11 is controlled according to the engine output torque limit line LL.
  • step S7 the transmission controller 106 uses the engine speed sensor 101 to detect the engine speed, and determines whether or not the detected engine speed is outside a predetermined range. Specifically, the transmission controller 106 stores the detected engine speed equal to or greater than a value obtained by adding a predetermined value to the maximum engine speed N_eng_max stored in the process of step S4, or stored in the process of step S4. It is determined whether or not the value is equal to or less than a value obtained by subtracting a predetermined value from the minimum value N_eng_min of the engine 11 rotation speed. The predetermined value added or subtracted here corresponds to the second predetermined value according to the present invention.
  • the value added or subtracted to the maximum value N_eng_max and the minimum value N_eng_min of the engine 11 takes into account the fluctuation value of the engine 11 that may occur when the wheel loader 1 is traveling on the road surface. It is a preset value, for example, a value of about 10 rpm. This is in order to avoid frequent hunting of the control by deviating from the control of the present invention as soon as the stored maximum value N_eng_max or minimum value N_eng_min of the engine speed is exceeded.
  • the transmission controller 106 advances the engine control process to the process of step S8.
  • the transmission controller 106 returns the engine control process to the process of step S5.
  • step S8 the transmission controller 106 determines that the engine speed maximum value N_eng_max and the minimum value N_eng_min, the engine speed average value N_eng_ave, and the engine output torque average value stored by the processes of step S3 and step S4.
  • the data T_eng_ave is deleted from the storage unit 106a.
  • step S9 the output torque restriction by the output torque restriction line LL is released.
  • FIG. 5 is a diagram for explaining the engine control process when the engine speed is within the predetermined range
  • FIG. 6 is a diagram for explaining the engine control process when the engine speed is outside the predetermined range
  • FIG. 7 is a diagram showing a change with time of the fuel injection amount by the engine control process shown in FIG.
  • the transmission controller 106 limits the output torque of the engine 11 along the engine output torque limit line LL as shown by the arrow B, and suppresses unnecessary fuel injection.
  • the transmission controller 106 sets the regulation line RL as indicated by an arrow A so that unnecessary fuel injection is not performed. Along with this, the output torque of the engine 11 is controlled.
  • the transmission controller 106 controls the fuel injection amount along the regulation line RL.
  • R max indicates a value obtained by adding a predetermined value to the maximum engine speed N_eng_max stored in step S4
  • R min indicates the minimum engine speed N_eng_min stored in step S4. Indicates a value obtained by subtracting a predetermined value from. Note that the value of R max may coincide with the maximum value N_eng_max.
  • the transmission controller 106 limits the output torque of the engine 11 when the rotational speed of the engine 11 fluctuates within a minute range while the wheel loader 1 is traveling stably.
  • the fuel injection amount that is equal to or greater than the fuel injection amount F 0 required to output the engine output torque necessary for stable running is limited.
  • the fuel injection amount by the conventional engine control process shown in FIG. 9 it is possible to suppress unnecessary fuel injection during stable running and improve fuel efficiency during stable running.
  • the transmission controller 106 determines whether or not the wheel loader 1 is in a stable running state based on the engine speed, so that the wheel loader 1 is stable. It is not necessary for the operator to perform setting operation to be in the running state, and the operator's labor can be reduced.
  • the engine output torque is limited when the engine speed is equal to or lower than the average engine speed N_eng_ave.
  • the engine output torque may be limited when the engine speed is equal to or lower than the engine speed (steps S15 and S16).
  • a matching point exists for each accelerator opening. The engine speed of the matching point can be obtained by referring to the map or by calculating.
  • the running torque based on the speed stage is stored, and the engine speed of the matching point can be calculated for each accelerator opening.
  • the traveling torque can be calculated from the actual load state, road surface state, and operating state of the traveling device, and the engine speed at the matching point can be calculated for each accelerator opening.
  • the transmission controller 106 limits the output torque of the engine 11 based on the average value T_eng_ave of the engine output torque.
  • the present invention is not limited to this embodiment.
  • the engine output torque The output torque of the engine 11 may be limited based on a value equal to or less than the average value T_eng_ave.
  • the fuel efficiency during stable running can be further reduced, but the engine speed is drastically decreased.
  • the engine operating state may become unstable. Therefore, it is desirable to limit the output torque of the engine 11 based on the most probable average value T_eng_ave as the output required during stable running.
  • other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.
  • the construction machine has been described as an example.
  • the present invention can be applied to general work vehicles including industrial vehicles such as forklifts and agricultural machinery such as tractors that control the fuel injection amount of the engine by an all-speed governor. it can.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Control Of Vehicle Engines Or Engines For Specific Uses (AREA)

Abstract

If the rotational speed of an engine is within the range Rmin to Rmax and falls below the average value for the rotational speed of the engine within a prescribed period of time, a transmission controller limits the output torque of the engine in conformity with an engine output torque limit line (LL) and suppresses unnecessary fuel injection. As a result, the output torque of the engine is limited when travelling stably, thus limiting the unnecessary consumption of fuel and improving fuel efficiency.

Description

作業車両のエンジン制御装置及びエンジン制御方法Engine control apparatus and engine control method for work vehicle
　本発明は、作業車両のエンジン制御装置及びエンジン制御方法に関する。 The present invention relates to an engine control device and an engine control method for a work vehicle.
　ホイールローダ等の建設機械は、エンジンの出力回転軸に連結された可変容量型の油圧ポンプを回転駆動し、油圧ポンプから吐出される圧油によって油圧アクチュエータを駆動することにより、作業機を動作させる。このため、建設機械では、油圧アクチュエータが作業負荷によらず安定的に駆動されるように、エンジン回転数が作業負荷の変動によって大きく変動しないことが求められる。このような背景から、建設機械では、エンジンの燃料噴射量を電気的に制御する電子ガバナとして、作業負荷の変動に対するエンジン回転数の変動が小さいオールスピードガバナが採用されている。 Construction machines such as wheel loaders operate a work machine by rotating a variable displacement hydraulic pump connected to an output rotation shaft of an engine and driving a hydraulic actuator by pressure oil discharged from the hydraulic pump. . For this reason, in the construction machine, it is required that the engine speed does not fluctuate greatly due to fluctuations in the work load so that the hydraulic actuator is stably driven regardless of the work load. Against this background, construction machinery employs an all-speed governor in which fluctuations in engine speed with respect to fluctuations in work load are small as an electronic governor that electrically controls the fuel injection amount of the engine.
特開２００４－９２５４４号公報JP 2004-92544 A
　しかしながら、上述したオールスピードガバナの燃料噴射方式には、以下に説明するような問題がある。以下、図８，９を参照して、オールスピードガバナの燃料噴射方式の問題点について説明する。 However, the above-described all-speed governor fuel injection system has the following problems. Hereinafter, the problem of the fuel injection system of the all speed governor will be described with reference to FIGS.
　図８は、建設機械が安定走行している時にオールスピードガバナによってエンジンの燃料噴射量を制御した場合における、エンジン回転数とエンジン出力トルクとの関係を示す図である。ここで、安定走行とは、所定時間内におけるエンジン回転数が所定の範囲内におさまっている状態で建設機械が走行していることを意味する。図８中、符号ＡＬは、建設機械を走行させるための走行系の吸収トルク曲線を示し、符号ＲＬは、オペレータのアクセルペダル操作量に対応し、エンジン出力の上限を決定するレギュレーションラインを示す。図８中では、レギュレーションラインＲＬは１本しか存在しないが、実際には、レギュレーションラインＲＬはアクセルペダル操作量（アクセル開度）毎に存在する。また、図９は、建設機械が安定走行している時にオールスピードガバナによってエンジンの燃料噴射量を制御した場合における、燃料噴射量の時間変化を示す図である。 FIG. 8 is a diagram showing the relationship between the engine speed and the engine output torque when the fuel injection amount of the engine is controlled by the all speed governor when the construction machine is running stably. Here, the stable running means that the construction machine is running in a state where the engine speed within a predetermined time is within a predetermined range. In FIG. 8, symbol AL indicates an absorption torque curve of a traveling system for traveling a construction machine, and symbol RL indicates a regulation line that determines the upper limit of the engine output corresponding to the accelerator pedal operation amount of the operator. In FIG. 8, there is only one regulation line RL, but actually there is a regulation line RL for each accelerator pedal operation amount (accelerator opening). FIG. 9 is a diagram showing a change over time in the fuel injection amount when the fuel injection amount of the engine is controlled by the all speed governor when the construction machine is running stably.
　建設機械が走行する際に、エンジン出力は、走行系で吸収される吸収トルクとエンジン出力とが一致するように制御される。走行系で吸収される吸収トルクは、ある一定のトルクコンバータの速度比において、図８に示す曲線ＡＬのように変化する。速度比は、建設機械の発進直後の加速中に低く、安定走行時には高い。図８中の曲線ＡＬ’は、加速中の吸収トルクを示し、例えば速度比で０．３である。一方、図８中の曲線ＡＬは、安定走行時の吸収トルクを示し、例えば速度比で０．８である。速度比が高くなると、曲線ＡＬ’は高トルク側から低トルク側に移動し、曲線ＡＬとなる。すなわち、走行系で吸収される吸収トルクは、加速中は、大きく、徐々に減少する。そして、走行系で吸収される吸収トルクは、安定走行中は、低い値でほぼ一定となる。このため、走行系で吸収される吸収トルクを、エンジンによって出力することができるエンジン回転数は、レギュレーションラインＲＬ上で一定となる。吸収トルク曲線ＡＬとレギュレーションラインＲＬとの交点をマッチング点という。 When the construction machine travels, the engine output is controlled so that the absorption torque absorbed by the traveling system matches the engine output. The absorption torque absorbed by the traveling system changes as shown by a curve AL shown in FIG. 8 at a certain speed ratio of the torque converter. The speed ratio is low during acceleration immediately after the construction machine starts, and is high during stable running. A curve AL ′ in FIG. 8 indicates the absorption torque during acceleration, and is, for example, a speed ratio of 0.3. On the other hand, a curve AL in FIG. 8 indicates the absorption torque during stable running, and is, for example, 0.8 in speed ratio. As the speed ratio increases, the curve AL ′ moves from the high torque side to the low torque side to become the curve AL. That is, the absorption torque absorbed by the traveling system is large during acceleration and gradually decreases. The absorbed torque absorbed by the traveling system is substantially constant at a low value during stable traveling. For this reason, the engine speed at which the engine can output the absorption torque absorbed by the traveling system is constant on the regulation line RL. The intersection of the absorption torque curve AL and the regulation line RL is called a matching point.
　ここで、建設機械が安定走行している時に、エンジンの回転数が、走行系の吸収トルク曲線ＡＬとレギュレーションラインＲＬとのマッチング点Ｍに対応するエンジン回転数Ｒ０を中心に、所定範囲ΔＲ内で増減した場合を考える。なお、このようなエンジン回転数の変動は、路面の形状や走行抵抗の変化等の走行負荷の変化に起因する。この場合、オールスピードガバナは、作業負荷の変動によってエンジン回転数が増減した時と同様、図９に示すように、エンジン回転数Ｒ０に対応する燃料噴射量Ｆ０に対し燃料噴射量を増減させる。つまり、負荷が増加し、エンジン回転数が低下した場合、オールスピードガバナは、その低下したエンジン回転数に一致する出力がでるようにレギュレーションラインＲＬに従って燃料噴射量を増加させる。一方、負荷が減少し、エンジン回転数が上昇した場合には、オールスピードガバナは、レギュレーションラインＲＬに従って燃料噴射量を減少させる。すなわち、オールスピードガバナは、建設機械が安定走行しており、エンジン回転数を目標回転数に設定していない時であっても、図８に示すように、レギュレーションラインＲＬに沿ってエンジン出力トルクＴｍａｘ～Ｔｍｉｎの範囲内でエンジン出力トルクを増減させる。なお、上述したように、レギュレーションラインＲＬはアクセル開度毎に存在するので、マッチング点もアクセル開度毎に存在することになる。 Here, when the construction machine is traveling stably, the engine speed is within a predetermined range ΔR centering on the engine speed R0 corresponding to the matching point M between the absorption torque curve AL and the regulation line RL of the traveling system. Let's consider the case of increasing or decreasing. Note that such fluctuations in engine speed are caused by changes in travel load such as changes in road surface shape and travel resistance. In this case, the all speed governor increases or decreases the fuel injection amount with respect to the fuel injection amount F 0 corresponding to the engine speed R 0 , as shown in FIG. Let That is, when the load increases and the engine speed decreases, the all speed governor increases the fuel injection amount according to the regulation line RL so that an output that matches the decreased engine speed is generated. On the other hand, when the load decreases and the engine speed increases, the all speed governor decreases the fuel injection amount according to the regulation line RL. That is, in the all speed governor, even when the construction machine is running stably and the engine speed is not set to the target speed, the engine output torque along the regulation line RL as shown in FIG. Increase or decrease the engine output torque within the range of T max to T min . As described above, since the regulation line RL exists for each accelerator opening, a matching point also exists for each accelerator opening.
　このため、オールスピードガバナによる燃料噴射方式では、建設機械が安定走行している場合であっても、走行負荷の変動に対するエンジン回転数の変動を小さくするためにエンジン出力トルクが増減されることによって、燃料が無駄に消費され、燃費が悪化する要因となる。以上のことから、安定走行時の燃費を向上可能な作業車両のエンジン制御装置及びエンジン制御方法の提供が望まれている。 For this reason, in the fuel injection method using the all speed governor, even when the construction machine is running stably, the engine output torque is increased or decreased in order to reduce the fluctuation of the engine speed relative to the fluctuation of the running load. , Fuel is wasted, causing fuel consumption to deteriorate. In view of the above, it is desired to provide an engine control device and an engine control method for a work vehicle that can improve fuel efficiency during stable running.
　本発明は、上記に鑑みてなされたものであって、安定走行時の燃費を低減可能な作業車両のエンジン制御装置及びエンジン制御方法を提供することを目的とする。 The present invention has been made in view of the above, and an object thereof is to provide an engine control device and an engine control method for a work vehicle that can reduce fuel consumption during stable running.
　上記課題を解決し、目的を達成するために、本発明に係る作業車両のエンジン制御装置は、オールスピードガバナによってエンジンの燃料噴射量を制御する作業車両のエンジン制御装置であって、エンジン回転数を検出するエンジン回転数検出手段と、エンジン回転数検出手段によって検出されたエンジン回転数に基づいて、所定時間内におけるエンジン回転数の変動が所定範囲内にあるか否かを判別し、所定時間内におけるエンジン回転数の変動が所定範囲内にある場合、作業車両が安定走行状態であると判定する判定手段と、判定手段によって作業車両が安定走行状態であると判定され、前記エンジン回転数検出手段によって検出されたエンジン回転数が所定値以下である場合、エンジンの出力トルクを制限するようにエンジンの燃料噴射量を制御する制御手段と、を備える。 In order to solve the above problems and achieve the object, an engine control device for a work vehicle according to the present invention is an engine control device for a work vehicle that controls the fuel injection amount of the engine with an all-speed governor, and the engine speed is Based on the engine speed detected by the engine speed detecting means and the engine speed detected by the engine speed detecting means, it is determined whether or not the fluctuation of the engine speed within a predetermined time is within a predetermined range. When the fluctuation of the engine speed is within a predetermined range, the determination means for determining that the work vehicle is in a stable running state and the determination means determine that the work vehicle is in a stable running state, and detecting the engine speed When the engine speed detected by the means is below a predetermined value, the engine fuel is limited so as to limit the engine output torque. And a control means for controlling the injection amount, the.
　上記課題を解決し、目的を達成するために、本発明に係る作業車両のエンジン制御方法は、オールスピードガバナによってエンジンの燃料噴射量を制御する作業車両のエンジン制御方法であって、エンジン回転数を検出する検出ステップと、検出ステップにおいて検出されたエンジン回転数に基づいて、所定時間内におけるエンジン回転数の変動が所定範囲内にあるか否かを判別し、所定時間内におけるエンジン回転数の変動が所定範囲内にある場合、作業車両が安定走行状態であると判定する判定ステップと、判定ステップにおいて作業車両が安定走行状態であると判定され、検出ステップにおいて検出されたエンジン回転数が所定値以下である場合、エンジンの出力トルクを制限するようにエンジンの燃料噴射量を制御する制御ステップと、を含む。 In order to solve the above problems and achieve the object, an engine control method for a work vehicle according to the present invention is an engine control method for a work vehicle that controls the fuel injection amount of the engine by an all-speed governor, the engine speed being Based on the detection step for detecting the engine speed and the engine speed detected in the detection step, it is determined whether or not the fluctuation of the engine speed within a predetermined time is within a predetermined range, and the engine speed within the predetermined time is determined. When the fluctuation is within a predetermined range, a determination step for determining that the work vehicle is in a stable running state, and a determination step determines that the work vehicle is in a stable running state, and the engine speed detected in the detection step is predetermined. If the value is less than the value, a control step for controlling the fuel injection amount of the engine so as to limit the engine output torque. And, including the.
　本発明に係る作業車両のエンジン制御装置及びエンジン制御方法によれば、安定走行時にはエンジンの出力トルクが制限されるので、安定走行時に燃料が無駄に消費されることを抑制し、安定走行時の燃費を低減させることができる。 According to the engine control device and the engine control method for a work vehicle according to the present invention, since the output torque of the engine is limited at the time of stable traveling, it is possible to suppress wasteful consumption of fuel at the time of stable traveling, Fuel consumption can be reduced.
図１は、本発明の一実施形態であるホイールローダの全体構成を示す側面概略構成図である。FIG. 1 is a schematic side view showing the overall configuration of a wheel loader according to an embodiment of the present invention. 図２は、図１に示すホイールローダのエンジンの動作を制御するエンジン制御装置の構成を示すブロック図である。FIG. 2 is a block diagram showing a configuration of an engine control device that controls the operation of the engine of the wheel loader shown in FIG. 図３は、図２に示すエンジン制御装置によるエンジン制御処理の流れを示すフローチャートである。FIG. 3 is a flowchart showing a flow of engine control processing by the engine control apparatus shown in FIG. 図４は、エンジン出力トルク制限ラインマップの一例を示す図である。FIG. 4 is a diagram illustrating an example of an engine output torque limit line map. 図５は、エンジン回転数が所定範囲内にある場合のエンジン制御処理を説明するための図である。FIG. 5 is a diagram for explaining the engine control process when the engine speed is within a predetermined range. 図６は、エンジン回転数が所定範囲外になった場合のエンジン制御処理を説明するための図である。FIG. 6 is a diagram for explaining the engine control process when the engine speed is out of the predetermined range. 図７は、図５に示すエンジン制御処理による燃料噴射量の経時変化を示す図である。FIG. 7 is a diagram showing a change with time of the fuel injection amount by the engine control process shown in FIG. 図８は、建設機械が安定走行している時にオールスピードガバナによってエンジンの燃料噴射量を制御した場合における、エンジンの回転数と出力トルクとの関係を示す図である。FIG. 8 is a diagram showing the relationship between the engine speed and the output torque when the fuel injection amount of the engine is controlled by the all speed governor when the construction machine is running stably. 図９は、建設機械が安定走行している時にオールスピードガバナによってエンジンの燃料噴射量を制御した場合における、燃料噴射量の時間変化を示す図である。FIG. 9 is a diagram illustrating a change over time in the fuel injection amount when the fuel injection amount of the engine is controlled by the all speed governor when the construction machine is running stably. 図１０は、図２に示すエンジン制御処理の変形例を示すフローチャートである。FIG. 10 is a flowchart showing a modification of the engine control process shown in FIG.
　以下、図面を参照して、本発明の一実施形態であるホイールローダの構成及びそのエンジン制御処理の流れについて説明する。 Hereinafter, a configuration of a wheel loader according to an embodiment of the present invention and a flow of an engine control process thereof will be described with reference to the drawings.
〔ホイールローダの全体構成〕
　始めに、図１を参照して、本発明の一実施形態であるホイールローダの全体構成について説明する。 [Wheel loader overall configuration]
First, an overall configuration of a wheel loader that is one embodiment of the present invention will be described with reference to FIG.
　図１は、本発明の一実施形態であるホイールローダの全体構成を示す側面概略構成図である。図１に示すように、本発明の一実施形態であるホイールローダ１は、作業機２，フレーム部３，及び車体４を備える。 FIG. 1 is a schematic side view showing the overall configuration of a wheel loader according to an embodiment of the present invention. As shown in FIG. 1, a wheel loader 1 according to an embodiment of the present invention includes a work machine 2, a frame unit 3, and a vehicle body 4.
　作業機２は、リフトアーム５を備える。リフトアーム５は、基端部を揺動自在にしてフレーム部３に取り付けられている。フレーム部３とリフトアーム５とは、一対のリフトシリンダ６によって連結されている。リフトアーム５は、オペレータによる作業機レバーの操作に応じてリフトシリンダ６が伸縮することによって、揺動する。 The work machine 2 includes a lift arm 5. The lift arm 5 is attached to the frame portion 3 with a base end portion freely swingable. The frame portion 3 and the lift arm 5 are connected by a pair of lift cylinders 6. The lift arm 5 swings as the lift cylinder 6 expands and contracts according to the operation of the work implement lever by the operator.
　リフトアーム５の先端部にはバケット７が、略中央部にはベルクランク（チルトレバー）８が揺動自在に取り付けられている。ベルクランク８の一端部とフレーム部３とは、チルトシリンダ９によって連結されている。ベルクランク８の他端部とバケット７とは、チルトロッド１０によって連結されている。バケット７は、オペレータによる作業機レバーの操作に応じてチルトシリンダ９が伸縮することによって、揺動する。 The bucket 7 is attached to the tip of the lift arm 5 and the bell crank (tilt lever) 8 is swingably attached to the substantially central part. One end portion of the bell crank 8 and the frame portion 3 are connected by a tilt cylinder 9. The other end of the bell crank 8 and the bucket 7 are connected by a tilt rod 10. The bucket 7 swings as the tilt cylinder 9 expands and contracts according to the operation of the work implement lever by the operator.
　車体４には、ホイールローダ１を走行させるための走行装置と、走行装置に駆動出力を供給するエンジン１１とが搭載されている。走行装置は、ＰＴＯ機構１２，トルクコンバータ（Ｔ／Ｃ）１３，前後進切替及び複数段の変速段切替が可能なトランスミッション１４，トランスファ１５，及び前輪１６と後輪１７とを駆動する減速機１８を備える。エンジン１１の駆動出力は、ＰＴＯ機構１２，Ｔ／Ｃ１３，及びトランスミッション１４を順に介してトランスファ１５に伝達され、トランスファ１５によって前輪１６及び後輪１７側の減速機１８に伝達される。減速機１８は、トランスファ１５によって伝達されたエンジン１１の駆動出力を前輪１６及び後輪１７に伝達する。 The vehicle body 4 is equipped with a traveling device for traveling the wheel loader 1 and an engine 11 for supplying drive output to the traveling device. The traveling device includes a PTO mechanism 12, a torque converter (T / C) 13, a transmission 14 that can be switched forward and backward and a plurality of shift speeds, a transfer 15, and a speed reducer 18 that drives a front wheel 16 and a rear wheel 17. Is provided. The drive output of the engine 11 is transmitted to the transfer 15 via the PTO mechanism 12, the T / C 13, and the transmission 14 in order, and is transmitted to the speed reducer 18 on the front wheel 16 and rear wheel 17 side by the transfer 15. The speed reducer 18 transmits the driving output of the engine 11 transmitted by the transfer 15 to the front wheels 16 and the rear wheels 17.
　車体４には、図示しない作業機用制御弁を介してリフトシリンダ６とチルトシリンダ９とに圧油を供給する可変容量型の油圧ポンプ２０が搭載されている。油圧ポンプ２０は、ＰＴＯ機構１２を介してエンジン１１に連結され、エンジン１１の駆動出力の一部を使って駆動される。油圧ポンプ２０のポンプ容量は、図示しないコントローラが油圧ポンプ２０の斜板の傾斜角を変更することによって可変制御される。 The vehicle body 4 is equipped with a variable displacement hydraulic pump 20 that supplies pressure oil to the lift cylinder 6 and the tilt cylinder 9 via a work machine control valve (not shown). The hydraulic pump 20 is connected to the engine 11 via the PTO mechanism 12 and is driven using a part of the drive output of the engine 11. The pump capacity of the hydraulic pump 20 is variably controlled by changing the inclination angle of the swash plate of the hydraulic pump 20 by a controller (not shown).
　車体４の上部には、運転室２１が設けられている。運転室２１内には、運転者によって操作される変速機シフトレバー，アクセルペダル，ブレーキペダル，及び作業機２を操作するための作業機レバー等を含む運転操作装置２２が設けられている。運転者は、運転操作装置２２を操作することにより、ホイールローダ１の前後進の切り替え，走行速度の調節（加速と減速），及び作業機２の操作を行うことができる。 A driver's cab 21 is provided in the upper part of the vehicle body 4. A driving operation device 22 including a transmission shift lever, an accelerator pedal, a brake pedal, and a work implement lever for operating the work implement 2 operated by the driver is provided in the cab 21. The driver can operate the driving operation device 22 to perform forward / reverse switching of the wheel loader 1, adjustment of traveling speed (acceleration and deceleration), and operation of the work machine 2.
〔エンジン制御装置の構成〕
　次に、図２を参照して、ホイールローダ１のエンジン制御装置の構成について説明する。 [Configuration of engine control unit]
Next, the configuration of the engine control device of the wheel loader 1 will be described with reference to FIG.
　図２は、図１に示すホイールローダ１のエンジン１１の動作を制御するエンジン制御装置の構成を示すブロック図である。図２に示すように、エンジン制御装置１００は、エンジン回転数センサ１０１，エンジン出力トルクセンサ１０２，速度段センサ１０３，作業機レバーセンサ１０４，アクセルペダルセンサ１０５，トランスミッションコントローラ１０６，エンジンコントローラ１０７，及び作業機コントローラ１１１を備える。 FIG. 2 is a block diagram showing a configuration of an engine control device that controls the operation of the engine 11 of the wheel loader 1 shown in FIG. As shown in FIG. 2, the engine control apparatus 100 includes an engine speed sensor 101, an engine output torque sensor 102, a speed stage sensor 103, a work implement lever sensor 104, an accelerator pedal sensor 105, a transmission controller 106, an engine controller 107, and A work machine controller 111 is provided.
　エンジン回転数センサ１０１は、エンジン１１の出力回転軸に付設され、エンジン１１の回転数を検出する。エンジン回転数センサ１０１は、エンジン１１の回転数を示す電気信号をトランスミッションコントローラ１０６に入力する。エンジン回転数センサ１０１は、本発明に係るエンジン回転数検出手段として機能する。エンジン出力トルクセンサ１０２は、エンジン１１の出力回転軸に付設され、エンジン１１の出力トルクを検出する。エンジン出力トルクセンサ１０２は、エンジン１１の出力トルクを示す電気信号をトランスミッションコントローラ１０６に入力する。 The engine rotation speed sensor 101 is attached to the output rotation shaft of the engine 11 and detects the rotation speed of the engine 11. The engine speed sensor 101 inputs an electric signal indicating the speed of the engine 11 to the transmission controller 106. The engine speed sensor 101 functions as engine speed detection means according to the present invention. The engine output torque sensor 102 is attached to the output rotation shaft of the engine 11 and detects the output torque of the engine 11. The engine output torque sensor 102 inputs an electric signal indicating the output torque of the engine 11 to the transmission controller 106.
　速度段センサ１０３は、ホイールローダ１の速度段を切り替えるための速度段レバー１０８の位置を検出し、検出された位置を示す電気信号をトランスミッションコントローラ１０６に入力する。作業機レバーセンサ１０４は、リフトシリンダ６とチルトシリンダ９とを動作させるための作業機レバー１０９の操作量を検出し、検出された操作量を示す電気信号を作業機コントローラ１１１に入力する。作業機コントローラ１１１は、作業機レバーセンサ１０４から入力された電気信号に基づいて、トランスミッションコントローラ１０６及びエンジンコントローラ１０７を制御する。アクセルペダルセンサ１０５は、アクセルペダル１１０の操作量を検出し、検出された操作量を示す電気信号をトランスミッションコントローラ１０６に入力する。 The speed stage sensor 103 detects the position of the speed stage lever 108 for switching the speed stage of the wheel loader 1 and inputs an electric signal indicating the detected position to the transmission controller 106. The work implement lever sensor 104 detects an operation amount of the work implement lever 109 for operating the lift cylinder 6 and the tilt cylinder 9 and inputs an electric signal indicating the detected operation amount to the work implement controller 111. The work machine controller 111 controls the transmission controller 106 and the engine controller 107 based on the electrical signal input from the work machine lever sensor 104. The accelerator pedal sensor 105 detects an operation amount of the accelerator pedal 110 and inputs an electric signal indicating the detected operation amount to the transmission controller 106.
　トランスミッションコントローラ１０６は、ＣＰＵ，ＲＡＭ，ＲＯＭ，入出力回路等を含むマイクロコンピュータによって実現される。トランスミッションコントローラ１０６の記憶部１０６ａ内には、制御プログラムと、エンジン１１の回転数とエンジン出力トルク制限値との関係を示すエンジン出力トルク制限ラインマップとが予め記憶されている。エンジン出力トルク制限ラインマップの詳細については後述する。トランスミッションコントローラ１０６内のＣＰＵは、制御プログラムをＲＡＭ内にロードし、ＲＡＭ内にロードされた制御プログラムを実行することによって、エンジン回転数センサ１０１，エンジン出力トルクセンサ１０２，速度段センサ１０３，アクセルペダルセンサ１０５，及び作業機コントローラ１１１から入力される電気信号に従って、エンジン１１の動作を制御する制御信号をエンジンコントローラ１０７に出力する。トランスミッションコントローラ１０６は、本発明に係る判定手段及び制御手段として機能する。 The transmission controller 106 is realized by a microcomputer including a CPU, a RAM, a ROM, an input / output circuit, and the like. In the storage unit 106a of the transmission controller 106, a control program and an engine output torque limit line map indicating the relationship between the engine speed and the engine output torque limit value are stored in advance. Details of the engine output torque limit line map will be described later. The CPU in the transmission controller 106 loads the control program into the RAM, and executes the control program loaded into the RAM, whereby the engine speed sensor 101, the engine output torque sensor 102, the speed stage sensor 103, the accelerator pedal. A control signal for controlling the operation of the engine 11 is output to the engine controller 107 in accordance with an electrical signal input from the sensor 105 and the work machine controller 111. The transmission controller 106 functions as determination means and control means according to the present invention.
　エンジンコントローラ１０７は、ＣＰＵ，ＲＡＭ，ＲＯＭ，入出力回路等を含むマイクロコンピュータによって実現される。エンジンコントローラ１０７内には、制御プログラムが予め記憶されている。エンジンコントローラ１０７内のＣＰＵは、制御プログラムをＲＡＭ内にロードし、ＲＡＭ内にロードされた制御プログラムを実行することによって、トランスミッションコントローラ１０６及び作業機コントローラ１１１から入力される制御信号に従って、エンジン１１の動作を制御する。具体的には、エンジンコントローラ１０７内のＣＰＵは、トランスミッションコントローラ１０６から入力される制御信号に従ってエンジン１１の燃料噴射量を制御するオールスピードガバナ１１ａの動作を制御する。 The engine controller 107 is realized by a microcomputer including a CPU, a RAM, a ROM, an input / output circuit, and the like. A control program is stored in advance in the engine controller 107. The CPU in the engine controller 107 loads the control program into the RAM, and executes the control program loaded into the RAM, so that the engine 11 operates in accordance with control signals input from the transmission controller 106 and the work machine controller 111. Control the behavior. Specifically, the CPU in the engine controller 107 controls the operation of the all speed governor 11 a that controls the fuel injection amount of the engine 11 in accordance with a control signal input from the transmission controller 106.
　なお、本実施形態では、トランスミッションコントローラ１０６とエンジンコントローラ１０７とを別体により構成したが、トランスミッションコントローラ１０６とエンジンコントローラ１０７とを一体によって構成してもよい。また、トランスミッションコントローラ１０６やエンジンコントローラ１０７内に格納される制御プログラムやエンジン出力トルク制限ラインマップは、インストール可能な形式又は実行可能な形式のファイルでＣＤ－ＲＯＭ，フレキシブルディスク，ＣＤ－Ｒ，ＤＶＤ等のコンピュータが読み取り可能な記録媒体に記録して提供するように構成してもよい。また、制御プログラムやエンジン出力トルク制限ラインマップは、インターネット等のネットワークに接続されたコンピュータ上に格納し、ネットワーク経由でダウンロードさせることによって提供するように構成してもよい。また、制御プログラムやエンジン出力トルク制限ラインマップをインターネット等の電気通信回線を介して提供又は配布するように構成してもよい。また、各種センサからの電気信号が入力されるコントローラは一例であり、上記以外のコントローラに各種センサからの電気信号を入力するように構成してもよい。また、本実施形態では、エンジン出力トルクセンサ１０２によってエンジンの出力トルクを検出しているが、エンジン回転数や燃料噴射量、大気圧等からエンジンの出力トルクを計算により求めてもよい。 In the present embodiment, the transmission controller 106 and the engine controller 107 are configured separately, but the transmission controller 106 and the engine controller 107 may be configured integrally. The control program and engine output torque limit line map stored in the transmission controller 106 and engine controller 107 are files in an installable or executable format, such as CD-ROM, flexible disk, CD-R, DVD, etc. It may be configured to be recorded and provided on a computer-readable recording medium. The control program and the engine output torque limit line map may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Further, the control program and the engine output torque limit line map may be provided or distributed through a telecommunication line such as the Internet. Moreover, the controller to which electrical signals from various sensors are input is an example, and the electrical signals from various sensors may be input to controllers other than those described above. In this embodiment, the engine output torque is detected by the engine output torque sensor 102. However, the engine output torque may be obtained by calculation from the engine speed, the fuel injection amount, the atmospheric pressure, or the like.
〔エンジン制御処理〕
　このような構成を有するホイールローダ１では、エンジン制御装置１００が、以下に示すエンジン制御処理を実行することにより、建設機械が安定走行している時の燃費を低減する。以下、図３に示すフローチャートを参照して、エンジン制御装置１００によるエンジン制御処理の流れについて説明する。 [Engine control processing]
In the wheel loader 1 having such a configuration, the engine control apparatus 100 executes the engine control process described below, thereby reducing fuel consumption when the construction machine is traveling stably. Hereinafter, the flow of engine control processing by the engine control apparatus 100 will be described with reference to the flowchart shown in FIG.
　図３は、エンジン制御装置１００によるエンジン制御処理の流れを示すフローチャートである。エンジン制御装置１００によるエンジン制御処理は、ホイールローダ１のイグニッションスイッチがオフ状態からオン状態に切り替えられたタイミングで開始となり、ステップＳ１の処理に進む。 FIG. 3 is a flowchart showing the flow of engine control processing by the engine control apparatus 100. The engine control process by the engine control device 100 starts at the timing when the ignition switch of the wheel loader 1 is switched from the off state to the on state, and proceeds to the process of step S1.
　ステップＳ１の処理では、トランスミッションコントローラ１０６が、エンジン回転数センサ１０１とエンジン出力トルクセンサ１０２とを利用して、エンジン回転数とエンジン出力トルクとを検出し、所定時間（例えば５秒）内に検出されたエンジン回転数とエンジン出力トルクとを一時記憶する。これにより、ステップＳ１の処理は完了し、エンジン制御処理はステップＳ２の処理に進む。 In step S1, the transmission controller 106 detects the engine speed and the engine output torque using the engine speed sensor 101 and the engine output torque sensor 102, and detects them within a predetermined time (for example, 5 seconds). The stored engine speed and engine output torque are temporarily stored. Thereby, the process of step S1 is completed and the engine control process proceeds to the process of step S2.
　ステップＳ２の処理では、トランスミッションコントローラ１０６が、ステップＳ１の処理により記憶されたエンジン回転数に基づいて、ホイールローダ１が安定走行状態にあるか否かを判別する。具体的には、トランスミッションコントローラ１０６は、所定時間内におけるエンジン回転数の変動が所定範囲内にあるか否かを判別する。なお、所定時間の値は、ホイールローダ１が安定走行状態にあることを確実に検出して、エンジン制御が頻繁に切り替わるハンチングが発生することを抑制するために、５［ｓｅｃ］程度の時間に設定することが望ましい。 In the process of step S2, the transmission controller 106 determines whether or not the wheel loader 1 is in a stable travel state based on the engine speed stored in the process of step S1. Specifically, the transmission controller 106 determines whether or not the fluctuation of the engine speed within a predetermined time is within a predetermined range. Note that the value of the predetermined time is about 5 [sec] in order to reliably detect that the wheel loader 1 is in a stable running state and suppress occurrence of hunting in which engine control is frequently switched. It is desirable to set.
　また、所定範囲の値は、ホイールローダ１が路面を走行している際に走行負荷の変動によって生じ得るエンジン回転数の変動値を考慮して予め設定される値である。すなわち、エンジン回転数は路面の多少の凹凸によって変動する。従って、所定範囲の値は、路面の凹凸の影響を受けてもエンジン制御が頻繁に切り替わらない程度の値であることが望ましい。具体的には、所定範囲の値は１０［ｒｐｍ］程度の値である。判別の結果、所定時間内におけるエンジン回転数の変動が所定範囲内にある場合、トランスミッションコントローラ１０６は、ホイールローダ１は安定走行状態にあると判断し、エンジン制御処理をステップＳ３の処理に進める。一方、所定時間内におけるエンジン回転数の変動が所定範囲内にない場合には、トランスミッションコントローラ１０６は、ホイールローダ１は安定走行状態ではないと判断し、エンジン制御処理をステップＳ１の処理に戻す。 Further, the value in the predetermined range is a value set in advance in consideration of the fluctuation value of the engine speed that may be caused by the fluctuation of the traveling load when the wheel loader 1 is traveling on the road surface. That is, the engine speed varies due to some unevenness on the road surface. Therefore, it is desirable that the value in the predetermined range is a value that does not cause frequent switching of engine control even under the influence of road surface unevenness. Specifically, the value in the predetermined range is a value of about 10 [rpm]. As a result of the determination, if the fluctuation of the engine speed within the predetermined time is within the predetermined range, the transmission controller 106 determines that the wheel loader 1 is in a stable running state, and advances the engine control process to the process of step S3. On the other hand, if the fluctuation of the engine speed within the predetermined time is not within the predetermined range, the transmission controller 106 determines that the wheel loader 1 is not in a stable running state, and returns the engine control process to the process of step S1.
　ステップＳ３の処理では、トランスミッションコントローラ１０６が、ステップＳ１の処理によって記憶された所定時間内のエンジン回転数のうち、エンジン回転数の最大値N_eng_maxと最小値N_eng_minとを記憶部１０６ａに記憶する。これにより、ステップＳ３の処理は完了し、エンジン制御処理はステップＳ４の処理に進む。 In the process of step S3, the transmission controller 106 stores the maximum value N_eng_max and the minimum value N_eng_min of the engine speed among the engine speeds stored in the process of step S1 in the storage unit 106a. Thereby, the process of step S3 is completed and the engine control process proceeds to the process of step S4.
　ステップＳ４の処理では、トランスミッションコントローラ１０６が、ステップＳ１の処理によって記憶された所定時間内のエンジン回転数の平均値N_eng_aveとエンジン出力トルクの平均値T_eng_aveとを算出し、算出されたエンジン回転数の平均値N_eng_aveとエンジン出力トルクの平均値T_eng_aveとを記憶部１０６ａに記憶する。これにより、ステップＳ４の処理は完了し、エンジン制御処理はステップＳ５の処理に進む。 In the process of step S4, the transmission controller 106 calculates the average value N_eng_ave of the engine speed and the average value T_eng_ave of the engine output torque within the predetermined time stored by the process of step S1, and the calculated engine speed. The average value N_eng_ave and the average value T_eng_ave of the engine output torque are stored in the storage unit 106a. Thereby, the process of step S4 is completed, and the engine control process proceeds to the process of step S5.
　ステップＳ５の処理では、トランスミッションコントローラ１０６が、エンジン回転数センサ１０１を利用して、エンジン回転数を検出し、検出されたエンジン回転数がステップＳ４の処理によって算出されたエンジン回転数の平均値N_eng_ave以下であるか否かを判別する。判別の結果、エンジン回転数がエンジン回転数の平均値N_eng_ave以下である場合、トランスミッションコントローラ１０６は、エンジン制御処理をステップＳ６の処理に進める。一方、エンジン回転数がエンジン回転数の平均値N_eng_aveより大きい場合には、トランスミッションコントローラ１０６は、エンジン制御処理をステップＳ７の処理に進める。 In the process of step S5, the transmission controller 106 detects the engine speed using the engine speed sensor 101, and the detected engine speed is an average value N_eng_ave of the engine speeds calculated by the process of step S4. It is determined whether or not: As a result of the determination, if the engine speed is equal to or lower than the average engine speed N_eng_ave, the transmission controller 106 advances the engine control process to the process of step S6. On the other hand, when the engine speed is larger than the average engine speed N_eng_ave, the transmission controller 106 advances the engine control process to step S7.
　ステップＳ６の処理では、トランスミッションコントローラ１０６が、ステップＳ４の処理によって算出されたエンジン回転数の平均値N_eng_aveとエンジン出力トルクの平均値T_eng_aveとに基づいて、ステップＳ５の処理によって検出されたエンジン回転数に対応するエンジン出力トルク制限値を算出し、算出されたエンジン出力トルク制限値をエンジン出力トルク指令値としてエンジンコントローラ１０７に出力する。エンジンコントローラ１０７は、エンジン出力トルク指令値に従ってオールスピードガバナ１１ａを制御し、オールスピードガバナ１１ａは、エンジン出力トルク制限値に対応するエンジン出力トルクを出力するようにエンジン１１の燃料噴射量を制御する。これにより、ステップＳ６の処理は完了し、エンジン制御処理はステップＳ７の処理に進む。 In the process of step S6, the transmission controller 106 detects the engine speed detected by the process of step S5 based on the average value N_eng_ave of the engine speed calculated by the process of step S4 and the average value T_eng_ave of the engine output torque. The engine output torque limit value corresponding to is calculated, and the calculated engine output torque limit value is output to the engine controller 107 as an engine output torque command value. The engine controller 107 controls the all speed governor 11a according to the engine output torque command value, and the all speed governor 11a controls the fuel injection amount of the engine 11 so as to output the engine output torque corresponding to the engine output torque limit value. . Thereby, the process of step S6 is completed and the engine control process proceeds to the process of step S7.
　ここで、図４を参照して、エンジン出力トルク制限値の算出方法について説明する。図４は、トランスミッションコントローラ１０６の記憶部１０６ａ内に予め記憶されているエンジン出力トルク制限ラインマップの一例を示す図である。図４に示すように、エンジン出力トルク制限ラインマップは、最大出力トルクを１００％として、複数のエンジン出力トルク割合別のエンジン回転数とエンジン出力トルクとの関係を示すエンジン出力トルク制限ラインＬＬ１～ＬＬ６により構成されている。なお、図４に示すエンジン出力トルク割合の値は最大出力トルクに対する厳密な割合を示すものではない。すなわち、エンジン出力トルク割合の値は、エンジン出力トルクをある程度低下させるために、つまり燃料噴射量を制限するために、便宜的に数値化したものである。 Here, a method of calculating the engine output torque limit value will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of an engine output torque limit line map stored in advance in the storage unit 106 a of the transmission controller 106. As shown in FIG. 4, the engine output torque limit line map shows engine output torque limit lines LL1 to LL1 indicating the relationship between the engine speed and the engine output torque for each of a plurality of engine output torque ratios, with the maximum output torque being 100%. It is configured by LL6. Note that the value of the engine output torque ratio shown in FIG. 4 does not indicate a strict ratio with respect to the maximum output torque. That is, the value of the engine output torque ratio is quantified for convenience in order to reduce the engine output torque to some extent, that is, to limit the fuel injection amount.
　具体的には、トランスミッションコントローラによる処理でエンジン１１の出力トルクを２０％に制限するように決定した場合、トランスミッションコントローラ１０６はエンジン出力トルク制限ラインＬＬ２に従ってエンジン１１の出力トルクを制御する。つまり、トランスミッションコントローラ１０６は、エンジン出力トルク制限ラインＬＬ２を越えないように燃料噴射量を制御する。一方、トランスミッションコントローラ１０６による処理でエンジン１１の出力トルクを制限しない場合、すなわちエンジン出力トルクの割合を１００％とする場合には、トランスミッションコントローラ１０６は、エンジン出力トルク制限ラインＬＬ６に従ってエンジン１１の出力トルクを制御する。なお、曲線ＲＬ１は、スロットル開度が０［％］の時のレギュレーションラインを示す。 Specifically, when it is determined by the processing by the transmission controller that the output torque of the engine 11 is limited to 20%, the transmission controller 106 controls the output torque of the engine 11 according to the engine output torque limit line LL2. That is, the transmission controller 106 controls the fuel injection amount so as not to exceed the engine output torque limit line LL2. On the other hand, when the output torque of the engine 11 is not limited by the processing by the transmission controller 106, that is, when the ratio of the engine output torque is 100%, the transmission controller 106 outputs the output torque of the engine 11 according to the engine output torque limit line LL6. To control. A curve RL1 indicates a regulation line when the throttle opening is 0 [%].
　なお、図４に示すエンジン出力トルク制限ラインマップに規定されているエンジン出力トルク割合間の明記されていないエンジン出力トルク割合に対応するエンジン出力トルク制限ラインは補間処理によって求められる。具体的には、エンジン出力トルク割合が５０％のエンジン出力トルク制限ラインを求める場合、トランスミッションコントローラ１０６は、エンジン出力トルク割合４０％に対応するエンジン出力トルク制限ラインＬＬ３とエンジン出力トルク割合６０％に対応するエンジン出力トルク制限ラインＬＬ４とを用いた補間処理によってエンジン出力トルク割合５０％のエンジン出力トルク制限ラインを求める。また、エンジン出力トルク制限ラインは、図４に示すような傾きを持たずに水平であってもよい。つまり、エンジン出力トルク制限ラインは、負荷増大によるエンジン回転数の急激な低下を抑制するように構成されていればよく、図４に示すような直線状ではなく曲線状であってもよい。 Note that an engine output torque limit line corresponding to an unspecified engine output torque ratio between engine output torque ratios defined in the engine output torque limit line map shown in FIG. 4 is obtained by interpolation processing. Specifically, when obtaining an engine output torque limit line having an engine output torque ratio of 50%, the transmission controller 106 sets the engine output torque limit line LL3 corresponding to the engine output torque ratio 40% and the engine output torque ratio 60%. An engine output torque limit line having an engine output torque ratio of 50% is obtained by interpolation using the corresponding engine output torque limit line LL4. Further, the engine output torque limit line may be horizontal without an inclination as shown in FIG. That is, the engine output torque limit line only needs to be configured to suppress a rapid decrease in the engine speed due to an increase in load, and may be a curved line instead of a straight line as shown in FIG.
　ステップＳ６の処理においてエンジン出力トルク制限値を算出する際、トランスミッションコントローラ１０６は、エンジン出力トルク制限ラインマップから座標値（N_eng_ave，T_eng_ave）を通るエンジン出力トルク制限ラインＬＬを算出する。そして、トランスミッションコントローラ１０６は、ステップＳ５の処理によって検出されたエンジン回転数に対応するエンジン出力トルク制限ラインＬＬ上の位置を特定し、特定した位置のエンジン出力トルクをエンジン出力トルク制限値として算出する。これにより、エンジン１１の出力トルクは、エンジン出力トルク制限ラインＬＬに従って制御されるようになる。 When calculating the engine output torque limit value in the process of step S6, the transmission controller 106 calculates an engine output torque limit line LL that passes through the coordinate values (N_eng_ave, T_eng_ave) from the engine output torque limit line map. Then, the transmission controller 106 specifies the position on the engine output torque limit line LL corresponding to the engine speed detected by the process of step S5, and calculates the engine output torque at the specified position as the engine output torque limit value. . As a result, the output torque of the engine 11 is controlled according to the engine output torque limit line LL.
　ステップＳ７の処理では、トランスミッションコントローラ１０６が、エンジン回転数センサ１０１を利用して、エンジン回転数を検出し、検出されたエンジン回転数が所定範囲外の値であるか否かを判別する。具体的には、トランスミッションコントローラ１０６は、検出されたエンジン回転数が、ステップＳ４の処理によって記憶されたエンジン回転数の最大値N_eng_maxに所定値を加算した値以上、又は、ステップＳ４の処理によって記憶されたエンジン１１の回転数の最小値N_eng_minから所定値を減算した値以下であるか否かを判別する。ここで加算又は減算される所定値は、本発明に係る第２の所定値に対応する。 In step S7, the transmission controller 106 uses the engine speed sensor 101 to detect the engine speed, and determines whether or not the detected engine speed is outside a predetermined range. Specifically, the transmission controller 106 stores the detected engine speed equal to or greater than a value obtained by adding a predetermined value to the maximum engine speed N_eng_max stored in the process of step S4, or stored in the process of step S4. It is determined whether or not the value is equal to or less than a value obtained by subtracting a predetermined value from the minimum value N_eng_min of the engine 11 rotation speed. The predetermined value added or subtracted here corresponds to the second predetermined value according to the present invention.
　なお、エンジン１１の回転数の最大値N_eng_max及び最小値N_eng_minに加算又は減算される値は、ホイールローダ１が路面を走行している際に生じ得るエンジン１１の回転数の変動値を考慮して予め設定される値であり、例えば１０ｒｐｍ程度の値である。これは、記憶されたエンジン回転数の最大値N_eng_maxや最小値N_eng_minを超えた途端に本発明の制御から外れて、頻繁に制御のハンチングが発生することを避けるためである。 The value added or subtracted to the maximum value N_eng_max and the minimum value N_eng_min of the engine 11 takes into account the fluctuation value of the engine 11 that may occur when the wheel loader 1 is traveling on the road surface. It is a preset value, for example, a value of about 10 rpm. This is in order to avoid frequent hunting of the control by deviating from the control of the present invention as soon as the stored maximum value N_eng_max or minimum value N_eng_min of the engine speed is exceeded.
　判別の結果、エンジン１１の回転数が所定範囲外の値である場合、トランスミッションコントローラ１０６は、エンジン制御処理をステップＳ８の処理に進める。一方、エンジン１１の回転数が所定範囲外の値でない場合には、トランスミッションコントローラ１０６は、エンジン制御処理をステップＳ５の処理に戻す。 As a result of the determination, if the rotational speed of the engine 11 is a value outside the predetermined range, the transmission controller 106 advances the engine control process to the process of step S8. On the other hand, when the rotation speed of the engine 11 is not a value outside the predetermined range, the transmission controller 106 returns the engine control process to the process of step S5.
　ステップＳ８の処理では、トランスミッションコントローラ１０６が、ステップＳ３及びステップＳ４の処理によって記憶されたエンジン回転数の最大値N_eng_max及び最小値N_eng_minと、エンジン回転数の平均値N_eng_aveと、エンジン出力トルクの平均値T_eng_aveとのデータを記憶部１０６ａから消去する。その後、ステップＳ９の処理で、出力トルク制限ラインＬＬによる出力トルクの制限を解除する。これによって、上述した本エンジン制御処理は終了する。 In the process of step S8, the transmission controller 106 determines that the engine speed maximum value N_eng_max and the minimum value N_eng_min, the engine speed average value N_eng_ave, and the engine output torque average value stored by the processes of step S3 and step S4. The data T_eng_ave is deleted from the storage unit 106a. Thereafter, in the process of step S9, the output torque restriction by the output torque restriction line LL is released. As a result, the engine control process described above ends.
　最後に、図５乃至図７を参照して、このエンジン制御処理によって得られる技術的効果について説明する。図５は、エンジン回転数が所定範囲内にある場合のエンジン制御処理を説明するための図であり、図６は、エンジン回転数が所定範囲外になった場合のエンジン制御処理を説明するための図である。図７は、図５に示すエンジン制御処理による燃料噴射量の経時変化を示す図である。 Finally, the technical effect obtained by this engine control process will be described with reference to FIGS. FIG. 5 is a diagram for explaining the engine control process when the engine speed is within the predetermined range, and FIG. 6 is a diagram for explaining the engine control process when the engine speed is outside the predetermined range. FIG. FIG. 7 is a diagram showing a change with time of the fuel injection amount by the engine control process shown in FIG.
　図５に示すように、本発明の一実施形態であるエンジン制御処理では、エンジン１１の回転数が所定範囲Ｒｍｉｎ～Ｒｍａｘ内にある場合において、エンジン回転数が算出されたエンジン回転数の平均値N_eng_aveより低下した場合、トランスミッションコントローラ１０６が、矢印Ｂに示すように、エンジン出力トルク制限ラインＬＬに沿ってエンジン１１の出力トルクを制限し、不必要な燃料噴射を抑制する。 As shown in FIG. 5, in the engine control process according to an embodiment of the present invention, when the engine speed is within a predetermined range R min to R max , the calculated engine speed is calculated. When the average value N_eng_ave falls, the transmission controller 106 limits the output torque of the engine 11 along the engine output torque limit line LL as shown by the arrow B, and suppresses unnecessary fuel injection.
　一方、エンジン回転数が算出されたエンジン回転数の平均値N_eng_aveより増加した場合には、不必要な燃料噴射は行われないように、トランスミッションコントローラ１０６は、矢印Ａに示すようにレギュレーションラインＲＬに沿ってエンジン１１の出力トルクを制御する。エンジン出力トルク制限ラインＬＬを高回転側に延長した場合、燃料噴射量がレギュレーションラインＲＬより増加することになる。つまり不要な燃料噴射が行われることになる。このため、トランスミッションコントローラ１０６は、レギュレーションラインＲＬに沿って燃料噴射量を制御する。なお、Ｒｍａｘは、ステップＳ４の処理によって記憶されたエンジン回転数の最大値N_eng_maxに所定値を加算した値を示し、Ｒｍｉｎは、ステップＳ４の処理によって記憶されたエンジン回転数の最小値N_eng_minから所定値を減算した値を示す。なお、Ｒｍａｘの値は、最大値N_eng_maxと一致していてもよい。 On the other hand, when the engine speed increases from the calculated average engine speed N_eng_ave, the transmission controller 106 sets the regulation line RL as indicated by an arrow A so that unnecessary fuel injection is not performed. Along with this, the output torque of the engine 11 is controlled. When the engine output torque limit line LL is extended to the high rotation side, the fuel injection amount increases from the regulation line RL. That is, unnecessary fuel injection is performed. For this reason, the transmission controller 106 controls the fuel injection amount along the regulation line RL. R max indicates a value obtained by adding a predetermined value to the maximum engine speed N_eng_max stored in step S4, and R min indicates the minimum engine speed N_eng_min stored in step S4. Indicates a value obtained by subtracting a predetermined value from. Note that the value of R max may coincide with the maximum value N_eng_max.
　すなわち、トランスミッションコントローラ１０６は、ホイールローダ１が安定走行している状態においてエンジン１１の回転数が微小範囲内で変動した場合、エンジン１１の出力トルクを制限する。そして、このようなエンジン制御処理によれば、図７に示すように、安定走行に必要なエンジン出力トルクを出力するために必要な燃料噴射量Ｆ０以上の燃料噴射量が制限されるので、図９に示す従来のエンジン制御処理による燃料噴射量と比較して、安定走行時の不要な燃料噴射を抑制し、安定走行時の燃費を向上させることができる。 That is, the transmission controller 106 limits the output torque of the engine 11 when the rotational speed of the engine 11 fluctuates within a minute range while the wheel loader 1 is traveling stably. According to such an engine control process, as shown in FIG. 7, the fuel injection amount that is equal to or greater than the fuel injection amount F 0 required to output the engine output torque necessary for stable running is limited. Compared with the fuel injection amount by the conventional engine control process shown in FIG. 9, it is possible to suppress unnecessary fuel injection during stable running and improve fuel efficiency during stable running.
　また、図７と図９との比較から明らかなように、本発明の一実施形態であるエンジン制御処理によれば、従来のエンジン制御処理と比較して、不必要な燃料噴射を抑制しているので、燃料噴射量Ｆ０以上の燃料噴射量が減少する。また、過大な燃料噴射量が出たことにより、走行トルクが増大し、エンジン回転が加速され、過度に高回転になることも減少する。これにより、燃料噴射量の振動幅を小さくすることができる。また、本発明の一実施形態であるエンジン制御処理によれば、トランスミッションコントローラ１０６が、エンジン回転数に基づいてホイールローダ１が安定走行状態であるか否かを判別するので、ホイールローダ１が安定走行状態にあることをオペレータが設定操作する必要がなく、オペレータの労力を軽減することができる。 Further, as is clear from the comparison between FIG. 7 and FIG. 9, according to the engine control process which is one embodiment of the present invention, unnecessary fuel injection is suppressed as compared with the conventional engine control process. because there, the fuel injection amount F 0 or more fuel injection amount is reduced. Further, since the excessive fuel injection amount is generated, the running torque is increased, the engine rotation is accelerated, and the excessively high rotation is reduced. Thereby, the vibration width of the fuel injection amount can be reduced. Moreover, according to the engine control process which is one embodiment of the present invention, the transmission controller 106 determines whether or not the wheel loader 1 is in a stable running state based on the engine speed, so that the wheel loader 1 is stable. It is not necessary for the operator to perform setting operation to be in the running state, and the operator's labor can be reduced.
　また、本発明の一実施形態であるエンジン制御処理では、図６に示すように、エンジン１１の回転数が所定範囲外になった場合には、トランスミッションコントローラ１０６は、矢印Ｃに示すように、エンジン出力トルクの制限を解除し、レギュレーションラインＲＬに従ってエンジン出力トルクを増減させる。よって、エンジン１１の負荷が急激に高くなった場合にであっても、必要とされるエンジン出力トルクを応答性よく出力することができる。 In the engine control process according to the embodiment of the present invention, as shown in FIG. 6, when the rotational speed of the engine 11 is out of a predetermined range, the transmission controller 106 The restriction on the engine output torque is released, and the engine output torque is increased or decreased according to the regulation line RL. Therefore, even when the load on the engine 11 increases rapidly, the required engine output torque can be output with high responsiveness.
　以上、本発明者らによってなされた発明を適用した実施の形態について説明したが、本実施形態による本発明の開示の一部をなす記述及び図面により本発明は限定されることはない。例えば、本実施形態では、エンジン回転数がエンジン回転数の平均値N_eng_ave以下である場合にエンジン出力トルクを制限することとしたが、図１０に示すフローチャートのように、エンジン回転数がマッチング点のエンジン回転数以下である場合にエンジン出力トルクを制限するようにしてもよい（ステップＳ１５，１６の処理）。上述のように、マッチング点はアクセル開度毎に存在する。マッチング点のエンジン回転数はマップを参照する、又は、計算することによって求めることができる。本実施形態の場合、速度段に基づいた走行トルクを記憶しておき、アクセル開度毎にマッチング点のエンジン回転数を算出することができる。その他にも実際の積荷状態、路面状態、走行装置の稼働状態から走行トルクを算出し、アクセル開度毎にマッチング点のエンジン回転数を算出することもできる。 As mentioned above, although the embodiment to which the invention made by the present inventors is applied has been described, the present invention is not limited by the description and the drawings that form part of the disclosure of the present invention according to this embodiment. For example, in this embodiment, the engine output torque is limited when the engine speed is equal to or lower than the average engine speed N_eng_ave. However, as shown in the flowchart of FIG. The engine output torque may be limited when the engine speed is equal to or lower than the engine speed (steps S15 and S16). As described above, a matching point exists for each accelerator opening. The engine speed of the matching point can be obtained by referring to the map or by calculating. In the case of this embodiment, the running torque based on the speed stage is stored, and the engine speed of the matching point can be calculated for each accelerator opening. In addition, the traveling torque can be calculated from the actual load state, road surface state, and operating state of the traveling device, and the engine speed at the matching point can be calculated for each accelerator opening.
　また、本実施形態では、トランスミッションコントローラ１０６は、エンジン出力トルクの平均値T_eng_aveに基づいてエンジン１１の出力トルクを制限したが、本発明は本実施形態に限定されることはなく、例えばエンジン出力トルクの平均値T_eng_ave以下の値に基づいてエンジン１１の出力トルクを制限してもよい。但し、エンジン出力トルクの平均値T_eng_ave以下の値に基づいてエンジン１１の出力トルクを制限した場合には、安定走行時の燃費をより低減することができるが、エンジン回転数が急激に低下した場合、エンジンの運転状態が不安定になる可能性がある。従って、安定走行時に必要とされる出力として最も確からしい平均値T_eng_aveに基づいてエンジン１１の出力トルクを制限することが望ましい。このように、本実施形態に基づいて当業者等によりなされる他の実施形態、実施例、及び運用技術等は、全て本発明の範疇に含まれる。 In the present embodiment, the transmission controller 106 limits the output torque of the engine 11 based on the average value T_eng_ave of the engine output torque. However, the present invention is not limited to this embodiment. For example, the engine output torque The output torque of the engine 11 may be limited based on a value equal to or less than the average value T_eng_ave. However, when the output torque of the engine 11 is limited based on a value equal to or lower than the average value T_eng_ave of the engine output torque, the fuel efficiency during stable running can be further reduced, but the engine speed is drastically decreased. The engine operating state may become unstable. Therefore, it is desirable to limit the output torque of the engine 11 based on the most probable average value T_eng_ave as the output required during stable running. As described above, other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.
　なお、上述した実施形態では、建設機械を例にとって説明したが、オールスピードガバナによりエンジンの燃料噴射量を制御するフォークリフトなどの産業車両やトラクタなどの農業機械を含む作業車両全般に適用することができる。 In the above-described embodiment, the construction machine has been described as an example. However, the present invention can be applied to general work vehicles including industrial vehicles such as forklifts and agricultural machinery such as tractors that control the fuel injection amount of the engine by an all-speed governor. it can.
　１　ホイールローダ
　１１　エンジン
　１１ａ　オールスピードガバナ
　１００　エンジン制御装置
　１０１　エンジン回転数センサ
　１０２　エンジン出力トルクセンサ
　１０３　速度段レバーセンサ
　１０４　作業機レバーセンサ
　１０５　アクセルペダルセンサ
　１０６　トランスミッションコントローラ
　１０６ａ　記憶部
　１０７　エンジンコントローラ
　１０８　速度段切替レバー
　１０９　作業機レバー
　１１０　アクセルペダル
　１１１　作業機コントローラ DESCRIPTION OF SYMBOLS 1 Wheel loader 11 Engine 11a All speed governor 100 Engine control apparatus 101 Engine speed sensor 102 Engine output torque sensor 103 Speed stage lever sensor 104 Work machine lever sensor 105 Accelerator pedal sensor 106 Transmission controller 106a Memory | storage part 107 Engine controller 108 Speed stage switching Lever 109 Work implement lever 110 Accelerator pedal 111 Work implement controller

Claims (7)

  1. 　オールスピードガバナによってエンジンの燃料噴射量を制御する作業車両のエンジン制御装置であって、
    　エンジン回転数を検出するエンジン回転数検出手段と、
    　前記エンジン回転数検出手段によって検出されたエンジン回転数に基づいて、所定時間内におけるエンジン回転数の変動が所定範囲内にあるか否かを判別し、所定時間内におけるエンジン回転数の変動が所定範囲内にある場合、作業車両が安定走行状態であると判定する判定手段と、
    　前記判定手段によって作業車両が安定走行状態であると判定され、前記エンジン回転数検出手段によって検出されたエンジン回転数が所定値以下である場合、エンジンの出力トルクを制限するようにエンジンの燃料噴射量を制御する制御手段と、
    　を備えることを特徴とする作業車両のエンジン制御装置。     An engine control device for a work vehicle that controls the fuel injection amount of an engine by an all speed governor,
    An engine speed detecting means for detecting the engine speed;
    Based on the engine speed detected by the engine speed detecting means, it is determined whether or not the engine speed fluctuation within a predetermined time is within a predetermined range, and the engine speed fluctuation within the predetermined time is predetermined. A determination means for determining that the work vehicle is in a stable running state when within the range;
    When the determination means determines that the work vehicle is in a stable running state and the engine speed detected by the engine speed detection means is equal to or less than a predetermined value, the fuel injection of the engine is limited so as to limit the engine output torque. Control means for controlling the amount;
    An engine control device for a work vehicle, comprising:
  2. 　前記所定値は、前記所定時間内におけるエンジン回転数の平均値であることを特徴とする請求項１に記載の作業車両のエンジン制御装置。 2. The engine control device for a work vehicle according to claim 1, wherein the predetermined value is an average value of engine speeds within the predetermined time.
  3. 　前記制御手段は、前記エンジン回転数検出手段によって検出されたエンジン回転数が走行系の吸収トルク曲線とレギュレーションラインとのマッチング点に対応するエンジン回転数以下のエンジン回転数である場合に、エンジンの出力トルクを制限することを特徴とする請求項１に記載の作業車両のエンジン制御装置。 When the engine speed detected by the engine speed detecting means is an engine speed equal to or lower than the engine speed corresponding to the matching point between the absorption torque curve of the traveling system and the regulation line, the control means The engine control device for a work vehicle according to claim 1, wherein output torque is limited.
  4. 　前記制御手段は、前記所定時間内におけるエンジン回転数及び出力トルクの平均値を算出し、算出されたエンジン回転数及び出力トルクの平均値に基づいてエンジンの出力トルクの制限値を算出することを特徴とする請求項１又は請求項２に記載の作業車両のエンジン制御装置。 The control means calculates an average value of the engine speed and output torque within the predetermined time, and calculates a limit value of the engine output torque based on the calculated average value of the engine speed and output torque. The engine control device for a work vehicle according to claim 1, wherein the engine control device is a work vehicle.
  5. 　前記制御手段は、前記所定時間内におけるエンジン回転数の平均値を前記所定値としたとき、エンジンのトルクカーブ上のエンジン出力トルクをエンジンの出力トルクの制限値として算出することを特徴とする請求項１乃至請求項３のうち、いずれか１項に記載の作業車両のエンジン制御装置。 The control means calculates an engine output torque on an engine torque curve as a limit value of the engine output torque when an average value of engine speeds within the predetermined time is the predetermined value. The engine control device for a work vehicle according to any one of claims 1 to 3.
  6. 　前記制御手段は、前記エンジン回転数検出手段によって検出されたエンジン回転数が、前記所定範囲内におけるエンジン回転数の最大値に第２の所定値を加算した値以上になった場合、又は、前記所定範囲内におけるエンジン回転数の最小値から第２の所定値を減算した値以下になった場合、エンジンの出力トルクの制限を解除することを特徴とする請求項１乃至請求項５のうち、いずれか１項に記載の作業車両のエンジン制御装置。 The control means, when the engine speed detected by the engine speed detecting means is equal to or greater than a value obtained by adding a second predetermined value to the maximum value of the engine speed within the predetermined range, or The engine output torque restriction is canceled when the engine speed becomes equal to or smaller than a value obtained by subtracting the second predetermined value from the minimum value of the engine speed within the predetermined range. The engine control device for a work vehicle according to any one of the preceding claims.
  7. 　オールスピードガバナによってエンジンの燃料噴射量を制御する作業車両のエンジン制御方法であって、
    　エンジン回転数を検出する検出ステップと、
    　前記検出ステップにおいて検出されたエンジン回転数に基づいて、所定時間内におけるエンジン回転数の変動が所定範囲内にあるか否かを判別し、所定時間内におけるエンジン回転数の変動が所定範囲内にある場合、作業車両が安定走行状態であると判定する判定ステップと、
    　前記判定ステップにおいて作業車両が安定走行状態であると判定され、前記検出ステップにおいて検出されたエンジン回転数が所定値以下である場合、エンジンの出力トルクを制限するようにエンジンの燃料噴射量を制御する制御ステップと、
    　を含むことを特徴とする作業車両のエンジン制御方法。     An engine control method for a work vehicle that controls the fuel injection amount of an engine by an all speed governor,
    A detection step for detecting the engine speed;
    Based on the engine speed detected in the detection step, it is determined whether or not the fluctuation of the engine speed within a predetermined time is within a predetermined range, and the fluctuation of the engine speed within the predetermined time is within the predetermined range. If there is a determination step for determining that the work vehicle is in a stable traveling state;
    When it is determined in the determination step that the work vehicle is in a stable running state and the engine speed detected in the detection step is a predetermined value or less, the fuel injection amount of the engine is controlled so as to limit the engine output torque. A control step to
    An engine control method for a work vehicle characterized by comprising:
PCT/JP2011/054198 2010-03-01 2011-02-24 Engine control device and engine control method for working vehicle WO2011108444A1 (en)

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GB2585901A (en) * 2019-07-22 2021-01-27 Caterpillar Inc Method of reducing fuel consumption in loaders, excavators, backhoe loaders and the like
CN112282944A (en) * 2019-07-22 2021-01-29 卡特彼勒公司 Method for reducing fuel consumption in a loader, excavator, backhoe loader or the like

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WO2005014990A1 (en) * 2003-08-11 2005-02-17 Komatsu Ltd. Hydraulic driving control device and hydraulic shovel with the control device
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JP2004150306A (en) * 2002-10-29 2004-05-27 Komatsu Ltd Controller of engine
WO2005014990A1 (en) * 2003-08-11 2005-02-17 Komatsu Ltd. Hydraulic driving control device and hydraulic shovel with the control device
JP2005163605A (en) * 2003-12-02 2005-06-23 Komatsu Ltd Drive controller of hybrid working machine

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GB2585901A (en) * 2019-07-22 2021-01-27 Caterpillar Inc Method of reducing fuel consumption in loaders, excavators, backhoe loaders and the like
CN112282944A (en) * 2019-07-22 2021-01-29 卡特彼勒公司 Method for reducing fuel consumption in a loader, excavator, backhoe loader or the like

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