WO2006028042A1 - 作業車両のエンジンの負荷制御装置 - Google Patents
作業車両のエンジンの負荷制御装置 Download PDFInfo
- Publication number
- WO2006028042A1 WO2006028042A1 PCT/JP2005/016237 JP2005016237W WO2006028042A1 WO 2006028042 A1 WO2006028042 A1 WO 2006028042A1 JP 2005016237 W JP2005016237 W JP 2005016237W WO 2006028042 A1 WO2006028042 A1 WO 2006028042A1
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- WIPO (PCT)
- Prior art keywords
- engine
- hydraulic
- variable displacement
- speed
- absorption torque
- Prior art date
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/226—Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2246—Control of prime movers, e.g. depending on the hydraulic load of work tools
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2292—Systems with two or more pumps
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2296—Systems with a variable displacement pump
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
- F04B17/05—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by internal-combustion engines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/06—Control using electricity
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/06—Control using electricity
- F04B49/065—Control using electricity and making use of computers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16N—LUBRICATING
- F16N13/00—Lubricating-pumps
- F16N13/02—Lubricating-pumps with reciprocating piston
- F16N13/06—Actuation of lubricating-pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B2203/00—Motor parameters
- F04B2203/06—Motor parameters of internal combustion engines
- F04B2203/0603—Torque
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16N—LUBRICATING
- F16N2210/00—Applications
- F16N2210/16—Pumps
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S417/00—Pumps
Definitions
- the present invention relates to a load control device for an engine of a work vehicle.
- a wheel loader travels by driving wheels (wheels) driven by an engine as a drive source via a torque converter.
- the engine is also the driving source for working machines such as steering mechanisms and loaders.
- the steering hydraulic pump is driven by the engine and supplied to the hydraulic pressure steering hydraulic cylinder discharged from the steering hydraulic pump, and the steering mechanism is operated accordingly.
- the loader hydraulic pump is driven by the engine, and the pressure oil discharged from the loader hydraulic pump is supplied to the loader hydraulic cylinder, and the loader is operated accordingly.
- Fixed displacement hydraulic pumps with a constant capacity are used for steering hydraulic pumps and loader hydraulic pumps.
- the traveling speed of the wheel loader varies depending on the amount of depression of the accelerator pedal.
- the engine speed is changed according to the depression amount of the accelerator pedal, and the vehicle speed is changed accordingly.
- the target engine speed varies from a low idle speed to a high idle speed.
- the wheel loader has many opportunities to set the target engine speed to a low idle speed (idling state) as compared with other work vehicles such as hydraulic excavators.
- FIG. 3 shows the relationship between the engine speed N and the engine torque Te.
- the engine matches the hydraulic load on the regulation line FL corresponding to the low idle speed NL.
- the hydraulic load is low, the matching force at the low torque matching point V0 on the regulation line FL
- the operator suddenly operates the steering handle and the control lever, If the “high hydraulic load is applied suddenly by lifting the loader” is performed, the hydraulic load rises rapidly and the hydraulic load is switched to the line indicated by Tpl.
- the engine is subject to a sudden increase in hydraulic load as indicated by the force B at which the torque tends to increase to match this high hydraulic load Tpl (point VI on the regulation line FL). O The engine did not stop in time (a time delay occurred) and eventually the engine stopped.
- the engine idling speed is set to a higher value so that the torque increase during idling of the engine is accelerated, and the engine torque is increased rapidly when the high hydraulic load is increased. It is conceivable to keep up with the rise.
- the present invention has been made in view of such a situation, and in a working vehicle such as a wheel loader, a sudden increase in fuel efficiency, deterioration of vehicle body performance, waste of energy, etc. is caused without causing problems.
- the solution is to reliably prevent the engine from being stopped when the hydraulic load force S is applied.
- the first invention is a first invention.
- the absorption torque changing means (19, 22, 23) for changing the absorption torque For one or more variable displacement hydraulic pumps (7, 8, 9), the absorption torque changing means (19, 22, 23) for changing the absorption torque,
- the second invention is the first invention
- the predetermined threshold value is a rotational speed equal to or lower than a low idle rotational speed.
- a third invention is the first invention
- a fourth invention is the first invention
- the absorption torque changing means is means (19) for changing the maximum absorption torque of the hydraulic pump.
- the fifth invention is the first invention
- the absorption torque changing means is
- Capacity control means for controlling the capacity of the variable displacement hydraulic pump (8) so that the differential pressure between the discharge pressure of the variable displacement hydraulic pump (8) and the load pressure of the hydraulic actuator (14) becomes the set differential pressure (22 )When,
- a sixth invention is the first invention
- Pressure oil is supplied from multiple variable displacement hydraulic pumps (7, 8, 9) to multiple hydraulic actuators (13, 14, 15) via independent oil passages.
- the controller 18 determines that the engine speed Nr detected by the engine speed detection sensor la has dropped below the threshold value Nc, the controller 18 reduces the absorption torque of the variable displacement hydraulic pumps 7, 8, and 9. The control to be executed is executed.
- the controller 18 determines that the detected engine speed Nr has exceeded the threshold value Nc, the controller 18 ends the control for reducing the absorption torque of the variable displacement hydraulic pumps 7, 8, 9.
- the hydraulic load is a force that returns to the high-load line Tpl according to the current work content.
- the torque Te of the engine 1 has already increased to some extent during that time. Therefore, it can be matched at the matching point VI of the high hydraulic load Tpl.
- the control for reducing the absorption torque of the variable displacement hydraulic pumps 7, 8, 9 may be terminated.
- the control may be terminated after a predetermined time has elapsed since the start of the control for reducing the absorption torque of the variable displacement hydraulic pumps 7, 8, and 9.
- the time for reducing the absorption torque of the variable displacement hydraulic pumps 7, 8, and 9 is only the minimum time necessary to prevent the engine from stopping, and there is no risk of engine stop. Sometimes the absorption torque remains at normal magnitude. In addition, it is not necessary to increase the low idle speed NL. [0030] For this reason, when a work vehicle such as a wheel loader is subjected to a sudden high hydraulic load without causing problems such as deterioration of fuel consumption, deterioration of vehicle body performance, and waste of energy, the engine is stopped. Can be reliably prevented.
- the PC control is executed as shown by the arrow D in FIG. 5 by using the existing PC control and the function and device of “mode” selection in the wheel loader 100.
- the maximum absorption torque of the hydraulic pumps 7, 8, and 9 may be reduced (fourth invention).
- the existing PC control, “mode” selection function and device are used for the work vehicle, the device cost required to realize the engine stop prevention control can be further reduced.
- the existing LS control and differential pressure set value change control functions and devices are used for the wheel loader 100, and as shown by arrow E in FIG.
- the capacity of the hydraulic pumps 7, 8, and 9 may be reduced (fifth invention).
- the existing LS control and differential pressure set value change control functions and devices are used in the work vehicle, the device cost required to realize engine stop prevention control can be further reduced.
- a plurality of variable displacement hydraulic pumps 7, 8, 9 force are supplied to the plurality of hydraulic actuators 13, 14, 15 via respective independent oil passages. The engine stop prevention control described above is performed on the premise of the supplied hydraulic circuit.
- variable displacement hydraulic pumps 7, 8, and 9 are provided with a hydraulic circuit that supplies pressure oil to the plurality of hydraulic actuators 13, 14, and 15 via independent oil passages, respectively. If adopted, the capacity of the corresponding hydraulic pump 7, 8, 9 must be determined according to the maximum load of each hydraulic actuator 13, 14, 15, so each variable displacement hydraulic pump 7, The capacity of 8 and 9 tends to increase.
- the pressure oil discharged from a plurality of variable displacement hydraulic pumps is merged, and the differential pressure across each control valve is adjusted by the pressure compensation valve, and then a plurality of hydraulic actuators are combined. If a hydraulic circuit that supplies pressure oil separately is used, the flow rate can be distributed according to the load of each hydraulic actuator, so the capacity of each variable displacement hydraulic pump can be reduced. [0035] For this reason, the hydraulic circuit of the sixth invention shown in FIG. 1 tends to have a larger hydraulic load than the hydraulic circuit using the pressure compensation valve, and the necessity of performing engine stop prevention control is high. Yes.
- the seventh invention relates to
- An operating element (17) for setting a target engine speed according to an operation amount is provided, and the predetermined threshold is set according to an operating amount of the operating element (17), and the control means (18) is characterized in that when the detected engine speed force falls below the predetermined threshold value, the absorption torque of the variable displacement hydraulic pump (7, 8, 9) is reduced.
- an engine target speed NM corresponding to the depression amount SM is set (see Figs. 10 and 9 (a)). Also, the threshold Nc (SM) is determined according to the accelerator pedal depression amount SM at that time (see Fig. 10 and Fig. 9 (a)).
- the accelerator pedal 17 is depressed to the operation amount SM, and the low rotation / low hydraulic load matching point V0 (point V0 on the regulation line FL) is changed to the high rotation / high hydraulic load.
- the controller 18 determines whether or not the detected engine speed Nr force has fallen below the predetermined threshold Nc (SM). . If the controller 18 determines that the detected engine speed Nr has dropped below the predetermined threshold Nc (SM), the absorption torque of the variable capacity hydraulic pumps 7, 8, 9 is reduced. Execute control.
- the hydraulic load moves to the low hydraulic load line indicated by Tp2. Since the hydraulic load has changed from the high hydraulic load Tpl to the low hydraulic load Tp2, the torque of the current engine 1 now has a margin with respect to the low hydraulic load ⁇ 2, and the actual engine 1 speed Nr rises quickly.
- the time required to reduce the absorption torque of the variable displacement hydraulic pumps 7, 8, and 9 is only the minimum time required to prevent engine stoppage and acceleration deterioration.
- the absorption torque remains at the normal level.
- the accelerator pedal 17 when the accelerator pedal 17 is depressed even in a high hydraulic load state, it quickly rises to the target rotational speed Nc (SM), so that the acceleration performance is excellent and the working efficiency is high. The effect of dramatically improving can also be obtained.
- SM target rotational speed
- FIG. 1 shows the configuration of the wheel loader according to the embodiment, showing the parts according to the present invention.
- the output shaft of the engine 1 of the wheel loader 100 is connected to the PTO shaft 6.
- the PTO shaft 6 is connected to the torque converter 2, and is also connected to a steering hydraulic pump 7, a loader hydraulic pump 8, a fan hydraulic pump 9, and a torque converter lubrication hydraulic pump 10.
- the output of engine 1 is torque converter 2, transmission 3, and differential gear.
- the output of the engine 1 is transmitted to a steering hydraulic pump 7, a loader hydraulic pump 8, a fan hydraulic pump 9, and a torque converter lubricating hydraulic pump 10.
- the steering hydraulic cylinder 13 is connected to a steering mechanism.
- the steering mechanism When pressure oil is supplied to the steering hydraulic cylinder 13, the steering mechanism is activated and the vehicle body is turned.
- the spool of the steering control valve 11 is moved according to the operation of a steering handle (not shown), and the opening area of the control valve 11 changes accordingly, and the flow rate supplied to the steering hydraulic cylinder 13 changes. .
- the loader hydraulic cylinder 14 is connected to a loader at the front of the vehicle body.
- the loader When pressure oil is supplied to the loader hydraulic cylinder 14, the loader is activated. That is, the boom constituting the loader rises or falls, and the packet tilts.
- the spool of the loader control valve 12 is moved according to the operation of a loader operation lever (not shown), and the opening area of the control valve 12 is changed accordingly, and the flow rate supplied to the loader hydraulic cylinder 14 is changed.
- the engine 1 output shaft is provided with an engine speed detection sensor la that detects the actual speed Nr of the engine 1.
- the engine speed Nr detected by the engine speed detection sensor la is input to the controller 18.
- the accelerator pedal 17 is operated by an operator and is provided on the accelerator pedal 17.
- the stroke sensor 17a detects the operation amount (depression amount), and a signal indicating the operation amount is input to the controller 18.
- the controller 18 controls the engine 1 so that the target rotational speed is in accordance with the operation amount of the accelerator pedal 17.
- Engine 1 is a diesel engine, and its output is controlled by adjusting the amount of fuel injected into the cylinder. This adjustment is performed by controlling the governor attached to the fuel injection pump of engine 1.
- the governor an all-speed control type governor is generally used, and the engine speed and the fuel injection amount are adjusted according to the load so that the target speed depends on the accelerator pedal depression amount. In other words, the governor increases or decreases the fuel injection amount so that there is no difference between the target engine speed and the actual engine speed.
- FIG. 2 shows a control method of the engine 1.
- the horizontal axis in Fig. 2 is the engine speed N
- the vertical axis represents the engine torque Te.
- the region defined by the maximum torque line indicates the performance that the engine 1 can produce.
- the governor controls the engine 1 so that the torque does not exceed the maximum torque line and the exhaust smoke limit is not reached, and the engine speed N does not exceed the high idle speed NH and does not become overspeed.
- the low idle speed NL is set as the target speed, and the speed is adjusted on the regulation line FL connecting the low idle points NL.
- the hydraulic load Tp fluctuates as shown by arrow A, the matching point V at which the output of engine 2 and the pump absorption horsepower are balanced moves on the regulation line FL according to the fluctuation.
- variable displacement hydraulic pumps 7, 8, 9 are provided with absorption torque changing means for changing the absorption torque, and the controller 18 reduces the absorption torque as shown in FIG. The control to be executed is executed.
- the rotational speed Nc equal to or lower than the low idle rotational speed NL is set as the threshold! /.
- This threshold value Nc is set to a rotational speed at which it is determined that the engine 1 may stop.
- controller 18 determines that engine speed Nr detected by engine speed detection sensor la has decreased to a value equal to or lower than threshold value Nc (YES in step 201), variable displacement hydraulic pumps 7, 8 , Control to reduce the absorption torque of 9 is executed.
- the hydraulic load moves to the low hydraulic load line indicated by Tp2. Since the hydraulic load has changed from the high hydraulic load Tpl to the low hydraulic load Tp2 (point V2 on the regulation line FL), the torque of the current engine 1 is now reduced to the low hydraulic load ⁇ 2. As shown by C2, the actual engine speed Nr increases, exceeds the threshold Nc, and returns to the regulation line FL (step 202).
- step 204 if the detected engine speed Nr force exceeds the value Nc (YES in step 203), the absorption torque of the variable displacement hydraulic pumps 7, 8, 9 is reduced. (Step 204), and as shown in Fig. 11 (b), a predetermined time has elapsed since the start of the control to reduce the absorption torque of the variable displacement hydraulic pumps 7, 8, and 9. Later (YES at step 203 '), the control may be terminated (step 204).
- FIG. 7 shows a configuration for PC control of the loader hydraulic pump 8.
- the force shown as representative of the hydraulic pump 8 for the driver is configured similarly when the other variable displacement hydraulic pumps 7 and 9 are subjected to PC control.
- the PC valve 19 is arranged so that the product of the discharge pressure Pp (kg / cm2) of the hydraulic pump 8 and the capacity q (cc / rev) of the hydraulic pump 8 does not exceed a certain torque, Control the tilt angle. If the rotation speed of engine 1 is constant, the product of the discharge pressure Pp (kg / cm2) of hydraulic pump 8 and the flow rate Q (1 / min) of hydraulic pump 8 should not exceed a certain horsepower.
- the swash plate 8a of the pump 8 is controlled.
- the PC valve 19 inputs the discharge pressure Pp of the hydraulic pump 8 as a pilot pressure, and supplies the drive pressure oil corresponding to the discharge pressure Pp to the servo valve 20, thereby controlling the capacity q of the hydraulic pump 8. .
- the horizontal axis in Fig. 5 is the discharge pressure P of the hydraulic pump 8. p (kg / cm2), and the vertical axis represents the capacity q (cc / rev) of the hydraulic pump 8, that is, the tilt angle of the swash plate 8a.
- the pump capacity q is controlled in accordance with the pump discharge pressure Pp within a range not exceeding the hydraulic load, that is, the absorption torque force maximum absorption torque Tpl.
- a control signal il is applied to the PC valve 19 from the controller 18, and the maximum absorption torque is changed in accordance with the control signal il.
- An operation panel (not shown) is provided with a “mode switch”, and the maximum absorption torque value changes according to the mode selected by the mode switch.
- the maximum absorption torque of the hydraulic pump 8 is set to a large value Tpl, and the hydraulic pump 8 is controlled by the force having the characteristic LN1.
- Tpl the maximum absorption torque of the hydraulic pump 8
- the value changes from characteristic LN1 to characteristic LN2, and the pump discharge pressure value at which the pump capacity starts to decrease decreases, and the maximum absorption torque is reduced.
- Tp2 the value is set to a small value Tp2.
- control for preventing engine stop is performed using the PC control function, the “mode” setting function, and the device provided in the wheel loader 100 as described above.
- the controller 18 sets the maximum hydraulic pump 8 relative to the PC valve 19. Outputs the control signal il that sets the absorption torque to a large value Tpl.
- the maximum absorption torque of the hydraulic pump 8 is set to a small value Tp2 for the PC valve 19.
- the maximum absorption torque of the hydraulic pump 8 is set to a large value for the PC valve 19.
- the maximum absorption torque of the hydraulic pump 8 is set to a small value Tp2 and the force is also increased after a predetermined time.
- the wheel loader 100 can be used to stop the engine when a high hydraulic load is suddenly applied by using the existing PC control, "mode" selection function and device. Can be prevented.
- FIG. 8A shows a configuration for performing LS control on the loader hydraulic pump 8.
- the force shown as a representative of the loader hydraulic pump 8 is another variable displacement hydraulic pump.
- the LS valve 22 is a swash plate 8a of the hydraulic pump 8 so that the differential pressure ⁇ P between the discharge pressure Pp of the hydraulic pump 8 and the load pressure PLS of the loader hydraulic cylinder 14 becomes a constant differential pressure ⁇ PLS. Controls the tilt angle.
- a panel for setting a constant differential pressure ⁇ PLS is applied to the LS valve 22!
- the discharge pressure Pp of the hydraulic pump 8 is applied as a pilot pressure to the pilot port on the side opposite to the panel side of the LS valve 22, and the load pressure PLS of the loader hydraulic cylinder 14 is piloted to the pilot port on the panel side. It can be used as pressure.
- the drive pressure oil is supplied from the LS valve 22 to the servo valve 20, whereby the capacity q of the hydraulic pump 8 is controlled.
- the opening area A of the loader control valve 12 increases according to the operation amount, and the pump flow rate Q increases as the opening area A increases.
- the pump flow rate Q is not affected by the hydraulic load and is determined only by the operation amount of the loader operation lever.
- the engine 1 Even in the area where the maximum flow rate of the hydraulic pump 8 is not exceeded, such as during fine control, the engine 1 always supplies the flow rate required by the hydraulic cylinder 14 for the loader.
- the discharge flow rate is the same as the rotation range.
- the LS valve 22 is provided with a differential pressure setting unit 23 that changes the panel setting panel force.
- the controller 18 outputs a control signal i2 to the differential pressure setting unit 23, the differential pressure setting unit 23 Change the set panel force of the 22 panel and change the differential pressure setting value A PLS.
- the horizontal axis in FIG. 6 is the discharge pressure Pp (kg / cm2) of the hydraulic pump 8, and the vertical axis is the capacity q (cc / rev) of the hydraulic pump 8, that is, the tilt angle of the swash plate 8a.
- control for preventing engine stop is performed using the LS control function and the differential pressure set value change function provided in the wheel loader 100 described above.
- the controller 18 sets the differential pressure set value ⁇ PL to the LS valve 22.
- Set S to a large value and output control signal i2 to increase the absorption torque of hydraulic pump 8.
- the differential pressure set value A PLS is set to a small value for the LS valve 22. Outputs the control signal i2 to reduce the absorption torque of. Again, the engine speed detected by the engine speed sensor la exceeded the Nr force threshold value Nc or less.
- the control signal i2 for increasing the absorption torque of the hydraulic pump 8 is output to the LS valve 22 by setting the differential pressure setting value A PLS to a large value.
- the engine stop prevention control shown in Figs. 4 (a), (b), and (c) is realized, and the torque of the engine 1 without stopping the engine 1 is raised according to the hydraulic load to increase the high hydraulic load. Matching with Tpl's matching point VI is possible.
- the differential pressure set value ⁇ PLS is set to a small value and the absorption torque of the hydraulic pump 8 is reduced. After a predetermined time, the differential pressure set value ⁇ PLS is set to a large value to reduce the absorption torque of the hydraulic pump 8. Return the value to a large value.
- the engine in the case where a high hydraulic load is suddenly applied by using the existing LS control and differential pressure set value change control functions and devices in the wheel loader 100 is used. Stopping can be prevented.
- the engine stop may be prevented by combining the control for changing the maximum absorption torque shown in FIG. 5 and the control for changing the pump capacity shown in FIG.
- variable capacity can be reduced by reducing the maximum absorption torque or capacity for all variable displacement hydraulic pumps 7, 8, and 9.
- the maximum absorption torque or capacity may be reduced for one or two variable displacement hydraulic pumps of type 7, 8, 9
- independent oil passages are provided from the plurality of variable displacement hydraulic pumps 7, 8, 9 to the plurality of hydraulic actuators 13, 14, 15, respectively.
- variable displacement hydraulic pumps 7, 8, and 9 are provided with hydraulic circuits that supply pressure oil to the plurality of hydraulic actuators 13, 14, and 15 via independent oil passages, respectively. If adopted, the capacity of the corresponding hydraulic pump 7, 8, 9 must be determined according to the maximum load of each hydraulic actuator 13, 14, 15, so each variable displacement hydraulic pump 7, The capacity of 8 and 9 tends to increase.
- the pressure oil discharged from a plurality of variable displacement hydraulic pumps is merged, the differential pressure across each control valve is adjusted by the pressure compensation valve, and then a plurality of hydraulic actuators are combined. If a hydraulic circuit that supplies and distributes pressure oil is used, each hydraulic actuator Since the flow rate can be distributed according to the load, it is possible to reduce the capacity of each variable displacement hydraulic pump.
- the hydraulic circuit shown in FIG. 1 tends to have a larger hydraulic load than the hydraulic circuit using the pressure compensation valve, and it is highly necessary to perform engine stop prevention control.
- the engine stop prevention control shown in Fig. 4 is performed when the accelerator pedal 17 is not depressed and the engine speed is the idle idle speed NL. 4 may similarly perform the engine stop prevention control shown in FIG.
- the threshold value Nc for determining that the engine 1 may stop can be set to a different value depending on the current engine speed Nr. For example, when the engine is operating at a speed Nr higher than the low idle speed NL, the threshold value Nc for judging the engine stop is set to a speed slightly higher than the low idle speed NL. May be. Of course, regardless of the engine speed Nr, the threshold value Nc may be uniformly set to a speed equal to or lower than the low idle speed NL.
- the threshold value is set according to the depression amount (accelerator pedal opening) S of the accelerator pedal 17, and the value Nc (S) is used with the accelerator pedal operation amount S as a variable. Similarly, it is possible to perform control to reduce the pump absorption torque.
- the engine 1 regulation line is a low-rotation regulation line FL or Therefore, it is necessary to shift to the high rotation regulation line FM. In addition, it is necessary to shift the engine torque from low torque corresponding to low hydraulic load TpO to high torque corresponding to high hydraulic pressure Tpl.
- the threshold value Nc (S) is set according to the operation amount S (accelerator pedal opening) of the accelerator pedal 17. .
- This threshold value Nc (S) is a threshold value that determines that there is a risk of engine stoppage or acceleration acceleration, and the actual engine speed Nr is less than or equal to threshold value Nc (S) (same as above). If it is the region indicated by the slanted lines in FIG. 10, it is determined that there is a risk of engine stoppage or deterioration of acceleration, and control for reducing the absorption torque of the variable capacity hydraulic pumps 7, 8, 9 is executed.
- the straight line indicated by N (S) indicates the engine target speed (unloaded speed) that is set according to the operation amount S (accelerator pedal opening) of the accelerator pedal 17. It shows.
- the target engine speed NM corresponding to the depression amount SM is set (see Figs. 10 and 9 (a)). Also, the threshold Nc (SM) is determined according to the accelerator pedal depression amount SM at that time (see Fig. 10 and Fig. 9 (a)).
- the accelerator pedal 17 is depressed to the operation amount SM, and the low rotation / low hydraulic load matching point V0 (point V0 on the regulation line FL)
- the controller 18 determines whether or not the detected engine speed Nr force has fallen below the predetermined threshold Nc (SM).
- the controller 18 determines that the detected engine speed Nr has dropped below the predetermined threshold value Nc (SM)
- the variable capacity Control is performed to reduce the absorption torque of the quantity hydraulic pumps 7, 8, and 9.
- the hydraulic load moves to the low hydraulic load line indicated by Tp2. Since the hydraulic load has changed from the high hydraulic load Tpl to the low hydraulic load Tp2, the torque of the current engine 1 now has a margin with respect to the low hydraulic load ⁇ 2, and the actual engine 1 speed Nr rises quickly.
- the controller 18 In the process of moving to the matching point V0 (point V0 on the regulation line FL) of the low rotation low hydraulic load, the matching point V2 (point V2 on the regulation line FM) of the high rotation high hydraulic load, the controller 18 When it is determined that the detected engine speed Nr is not less than the predetermined threshold value Nc (S), the control for reducing the absorption torque of the variable displacement hydraulic pumps 7, 8, 9 is terminated. Let Alternatively, the control may be terminated after a predetermined time has elapsed after starting the control for reducing the absorption torque of the variable displacement hydraulic pumps 7, 8, and 9.
- the time during which the absorption torque of the variable displacement hydraulic pumps 7, 8, and 9 is reduced is only the minimum time necessary to prevent engine stoppage and acceleration failure. If there is no risk of engine stop or acceleration, the absorbed torque will remain at the normal level. In addition, it is not necessary to increase the engine size to allow a sufficient engine torque.
- the present invention is not limited to a wheel loader, and can be similarly applied to a work vehicle in which the engine speed changes from a wide speed (from a low idle speed to a high idle speed). it can.
- FIG. 1 is a diagram showing a configuration of a work vehicle according to an embodiment.
- FIG. 2 is a graph showing the relationship between engine speed and engine torque.
- FIG. 3 is a diagram for explaining how the engine stops in the prior art.
- FIGS. 4 (a), 4 (b), and 4 (c) are diagrams illustrating the contents of the engine stop prevention control of the embodiment.
- FIG. 5 is a diagram illustrating control for changing the maximum absorption torque of the hydraulic pump.
- FIG. 6 is a diagram for explaining control for changing the capacity of the hydraulic pump.
- FIG. 7 is a diagram showing a configuration example for performing PC control.
- FIG. 8 is a diagram showing a configuration example for performing LS control.
- Fig. 9 is a diagram for explaining the contents of the engine stop prevention control of the embodiment, and Fig. 9 (b) is a diagram showing a case where the engine stop prevention control is not performed as a comparative example.
- FIG. 10 is a graph showing the relationship between the accelerator pedal opening, the target engine speed, and the threshold value.
- FIGS. 11 (a) and 11 (b) are flowcharts for explaining the control contents of the embodiment.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Computer Hardware Design (AREA)
- Operation Control Of Excavators (AREA)
- Control Of Positive-Displacement Pumps (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE112005000083.4T DE112005000083B4 (de) | 2004-09-06 | 2005-09-05 | Lastregelvorrichtung für den Motor eines Arbeitsfahrzeugs |
US10/578,315 US7810323B2 (en) | 2004-09-06 | 2005-09-05 | Load control device for engine of work vehicle |
SE0600990A SE531422C2 (sv) | 2004-09-06 | 2006-05-04 | Belastningsstyrande anordning för en motor hos ett arbetsfordon |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004-258476 | 2004-09-06 | ||
JP2004258476A JP4410640B2 (ja) | 2004-09-06 | 2004-09-06 | 作業車両のエンジンの負荷制御装置 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2006028042A1 true WO2006028042A1 (ja) | 2006-03-16 |
Family
ID=36036323
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2005/016237 WO2006028042A1 (ja) | 2004-09-06 | 2005-09-05 | 作業車両のエンジンの負荷制御装置 |
Country Status (7)
Country | Link |
---|---|
US (1) | US7810323B2 (ja) |
JP (1) | JP4410640B2 (ja) |
KR (1) | KR100801930B1 (ja) |
CN (1) | CN1898471A (ja) |
DE (1) | DE112005000083B4 (ja) |
SE (1) | SE531422C2 (ja) |
WO (1) | WO2006028042A1 (ja) |
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EP2211042A1 (en) * | 2007-10-24 | 2010-07-28 | Hitachi Construction Machinery Co., Ltd | Engine control device for working vehicle |
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WO2020059130A1 (ja) * | 2018-09-21 | 2020-03-26 | 日立建機株式会社 | 油圧駆動ファン制御装置 |
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WO2015097910A1 (ja) * | 2013-12-27 | 2015-07-02 | 株式会社小松製作所 | フォークリフト及びフォークリフトの制御方法 |
KR102192740B1 (ko) * | 2014-04-24 | 2020-12-17 | 두산인프라코어 주식회사 | 건설기계의 엔진 및 유압펌프 통합 제어 장치 및 방법 |
WO2016041200A1 (en) * | 2014-09-19 | 2016-03-24 | Cummins, Inc. | Systems and methods for adaptive acceleration based speed control |
CN110469647A (zh) * | 2019-06-28 | 2019-11-19 | 中冶宝钢技术服务有限公司 | 一种用于静压驱动车辆的防超速液压装置 |
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- 2005-09-05 CN CNA2005800012934A patent/CN1898471A/zh active Pending
- 2005-09-05 DE DE112005000083.4T patent/DE112005000083B4/de active Active
- 2005-09-05 US US10/578,315 patent/US7810323B2/en active Active
- 2005-09-05 KR KR1020067008753A patent/KR100801930B1/ko not_active IP Right Cessation
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EP2211042A1 (en) * | 2007-10-24 | 2010-07-28 | Hitachi Construction Machinery Co., Ltd | Engine control device for working vehicle |
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Also Published As
Publication number | Publication date |
---|---|
SE0600990L (sv) | 2006-07-03 |
DE112005000083T5 (de) | 2007-07-26 |
CN1898471A (zh) | 2007-01-17 |
SE531422C2 (sv) | 2009-03-31 |
KR20060086377A (ko) | 2006-07-31 |
DE112005000083B4 (de) | 2019-03-07 |
JP2006070877A (ja) | 2006-03-16 |
JP4410640B2 (ja) | 2010-02-03 |
US7810323B2 (en) | 2010-10-12 |
US20090101101A1 (en) | 2009-04-23 |
KR100801930B1 (ko) | 2008-02-12 |
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