JP5386757B2 - Automatic idle speed control method for work vehicle engine and idle speed automatic control device for work vehicle engine - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an idle rotation speed control method and an idle rotation speed automatic control device for work vehicle engines such as a wheel loader and an off-road dumper when work is interrupted.

  In some work vehicles such as a wheel loader and an off-road dump, the output of the engine is distributed to the traveling machine and the work machine, and has a special configuration different from that of other general work vehicles.

  In these special work vehicles, there is a case where the work machine is driven to work even in a non-running state. Therefore, in consideration of this, the standard idle rotation speed can drive the engine stably without stalling the engine. It is set higher than the vicinity of the lower limit of the idle rotation speed, and is configured so that the work machine can be stably driven even when the engine is in an idling state in a traveling stop state.

  For this reason, the engine speed of the wheel loader is maintained at a relatively high standard idle speed even during a work interruption period such as waiting for a dump, which is a characteristic of waste of fuel during work interruption, increased noise and vibration, etc. There was a problem.

  In this regard, the applicant of the present application disclosed in Japanese Patent Application Laid-Open No. Sho 62-225727 (Patent Document 1) where the accelerator pedal, the steering, and the work implement lever are not operated, and the work implement is in a position where no work is performed. Has proposed a control device that lowers the engine speed below the standard idle speed after a certain period of time.

  When the technique described in Patent Document 1 is used, control is performed to reduce the idle rotation speed of the engine when the work is interrupted. Therefore, fuel consumption during stopping when the work is interrupted is saved, and noise and vibration are suppressed. be able to.

  However, work vehicles such as wheel loaders and off-road dumpers are often used in unsteady off-road environments such as unpaved road surfaces, inclined surfaces, or rough ground with a lot of ridges and irregularities. There is a high ratio that the work vehicle itself is inclined at a complicated angle in which the left and right directions are combined in the front-rear direction and the inclination angle is very large.

  In the technique disclosed in Patent Document 1, when the work vehicle is tilted as described above, when the control for reducing the rotation speed of the engine is executed when the work is interrupted, depending on the tilt state of the work vehicle, the traveling is resumed. Sometimes the moment the operator releases the brake, the work vehicle may begin to slide down the slope due to insufficient engine speed.

  When this sliding-down direction is a direction that the operator does not intend, there is a problem that the operator cannot instantaneously grasp the situation of the work vehicle and may cause the operator to shake.

  On the other hand, various techniques for controlling the rotational speed of a stopped engine have been proposed for general vehicles other than work vehicles.

  For example, Japanese Patent Laying-Open No. 2002-195079 (Patent Document 2) discloses a technique for increasing the rotational speed of an engine at the time of resuming traveling by measuring the inclination state of a vehicle.

  The technique described in Patent Document 2 prevents the generation of a turbo lag by increasing the engine idling speed in advance when starting from an idling state while stopping on an uphill road in a diesel engine.

  In such a general vehicle, the output of the engine is not distributed to the traveling machine and the work machine unlike a special work vehicle, and it is not necessary to secure the driving force of the work machine when the vehicle is stopped.

  For this reason, in a general vehicle, the standard idle rotation speed of the engine is normally set near the lower limit of the rotation speed at which the engine does not stall, and is not set as high as in a work vehicle.

  Also in the technique described in Patent Document 2, the standard idle rotation speed of the engine is set near the lower limit of the rotation speed at which the engine does not stall, and a higher idle rotation speed is required according to the inclination of the general vehicle. In this case, control is performed to increase the idle rotation speed from the normal low rotation idle rotation speed, and the idle rotation speed is temporarily increased.

  Therefore, the system that controls the engine idling speed in accordance with the inclination of the vehicle adopted in such a general vehicle is completely different from the system of the work vehicle, and the distribution of the engine output is completely different. It cannot be diverted to a work vehicle on the premise of adopting a special system.

  Also, in general vehicles, there is no room left to reduce the idle rotation speed to the extent that it affects fuel consumption even if the rotation speed of the stopped engine is controlled in order to reduce the fuel consumption rate. For example, as seen in a hybrid vehicle combining an internal combustion engine and a battery, a route bus, etc., it is necessary to automatically stop the engine when temporarily stopped to suppress fuel consumption. In the idle speed control technology, it is obvious that the technology cannot be used between the work vehicle and the general vehicle.

  Furthermore, in general vehicles, steep slopes such as construction sites, off-roads with irregular undulations, and a large slope in the left-right direction with respect to the traveling direction of the vehicle, or a front-rear, left-right slope is complicated. In order to solve the problem when starting a work vehicle under such an unforeseen condition, it is not possible to divert the technology of a general vehicle. Can not.

Japanese Unexamined Patent Publication No. 62-225727 JP 2002-195079 A

  The invention of the present application was made to solve the above-mentioned problem, and in a special work vehicle such as a wheel loader or an off-road dump, while ensuring safety, the rotational speed of the engine when the work is interrupted. The purpose is to improve the fuel consumption and reduce the exhaust gas amount, noise and vibration.

The above purpose is
An engine idle speed automatic control method for an engine for a work vehicle in which the output of the engine is distributed to a traveling machine and a work machine,
a) determining a stop state of the work vehicle, determining interruption of operation of the work machine, and determining a tilt state of the work vehicle;
b) When the stop of the work vehicle is determined, the interruption of the operation of the work machine is determined, and the tilt state of the work vehicle is the reference position in which the tilt angle in the front-rear and left-right directions is within a predetermined angle range. Performing a control to maintain the engine idle speed at a low idle speed lower than the standard idle speed;
This is achieved by the above-described method for automatically controlling the idle rotation speed of the engine for a work vehicle.

  When the above method is used, the engine speed is maintained at a low idle speed only when the work vehicle in which work has been suspended is stably stopped without tilting. There is no fear that the vehicle will slide back and forth against the intention of the operator, the fuel consumption and the exhaust gas amount can be effectively suppressed, and noise and vibration can be reduced.

Further, the above object is to provide an automatic idle speed control method for a work vehicle engine as described above.
It is determined that the work vehicle is stopped, the operation of the work machine is interrupted, and the left / right inclination state of the work vehicle is within a predetermined angle range, and the front and rear of the work vehicle When the tilt angle of the direction exceeds the predetermined angle range and the rearward tilt position is not lowered, the control is performed to maintain the engine idle speed at a low idle speed lower than the standard idle speed. May be.

  When the above method is used, the engine speed is maintained at a low idle speed only when the work vehicle in which the work is suspended is stopped in a state where there is no risk of sliding backward, so that the work or running is resumed. Sometimes, the work vehicle does not behave against the operator's intention and can be operated safely, and the fuel consumption and the amount of exhaust gas can be efficiently suppressed, and further the noise vibration can be reduced.

Further, the above object is to provide an automatic idle speed control method for a work vehicle engine as described above.
The inclination angle of the inclined plane on which the work vehicle is stopped is calculated based on the inclination angles in the front-rear direction and the left-right direction of the work vehicle, and the inclination state of the work vehicle is determined based on the inclination angle of the inclination plane. It may be.

  When the above method is used, the idle rotation speed can be controlled in accordance with the inclination of the inclined plane where the work vehicle is stopped, and the engine idle rotation speed can be controlled safely and efficiently. Further, exhaust gas emissions, noise and vibration can be further reduced.

Further, in the above-described idle speed automatic control method for a work vehicle engine,
When the engine rotation speed is maintained at a low idle rotation speed, the control for maintaining the engine rotation speed at a low idle rotation speed is canceled when at least one of brake release and work implement operation is executed. It is recommended to do.

  According to the above method, when the engine is maintained at a low idle rotation speed, it becomes possible to quickly return to running or work without causing unstable engine driving or engine stall.

  Further, in the above-described automatic idle speed control method for an engine for a work vehicle, the low idle rotation speed may include a stop of the engine.

  According to the above method, when a predetermined condition is satisfied, the engine is stopped, and fuel consumption, exhaust gas emission, noise, and vibration can be further reduced.

  Further, in the above-described automatic idle speed control method for a work vehicle engine, a plurality of low idle rotational speeds are set, and a predetermined low idle rotational speed is selected according to the inclination of the work vehicle. May be.

  When using the above method, the safest and most efficient low idle rotation speed can be set according to the state of the work vehicle, so that fuel consumption, exhaust gas emission, noise and vibration can be further reduced. Become.

  Further, in the above-described automatic idle speed control method for a work vehicle engine, vehicle stop state determination means, work state determination means, tilt state determination means, and engine idle rotation speed are controlled to a low idle rotation speed. It is recommended to use an automatic idle speed control device for an engine for a work vehicle that includes a low speed control means.

  According to the present invention, the necessity of control for reducing the idle rotation speed of the work vehicle is determined very accurately, so that fuel efficiency is improved and exhaust gas amount is reduced without sacrificing safety. Noise and vibration can be reduced.

FIG. 1 is a system configuration diagram showing a configuration of an automatic idle speed control apparatus for a working vehicle engine according to the present invention. FIG. 2 is a flowchart showing a control state of the idle rotation speed of the control device shown in FIG. FIG. 3 is a pattern diagram showing the relationship between the vehicle state and the idle rotation speed of the control device shown in FIG.

In the present invention, when the work vehicle with work interruption is stopped, the engine idle rotation speed at the time of work interruption is reduced by lowering the engine idle rotation speed from the standard idle rotation speed according to the inclination state of the work vehicle. The control to decrease can be executed safely.
Hereinafter, based on an Example, this invention is demonstrated concretely.

  In the present specification, “the work vehicle slides down when the brake is released” is not limited to a state where the work vehicle actually starts to slide down. It includes a state that is very close to the state of starting to fall, and includes a state that is considered to start to slide down.

  FIG. 1 is a system configuration diagram showing the configuration of an automatic idling speed control device for a work vehicle engine according to the present invention.

  In FIG. 1, 1 is an engine, 10 is a rotation speed sensor, 11 is a water temperature sensor, 2 is a controller, 3 is an electronic governor control means, 4 is a vehicle stop state determination means, 40 is a brake sensor, 41 is a speed sensor, and 42 is Timer 5, work state determination means, 50 work machine operation sensor, 51 work machine position sensor, 52 work machine load sensor, 53 steering operation sensor, 6 tilt state determination means, 60 front and rear tilt sensor, 61 Is a left / right tilt sensor, and 7 is a low rotational speed control means.

  In FIG. 1, the description of a configuration not directly related to the present invention, for example, a configuration of a traveling machine or a work machine connected to the output shaft of the engine is omitted.

  The engine 1 is a work vehicle, specifically a wheel loader engine. The output of the engine 1 is distributed to a traveling machine and a work machine via a PTO shaft (not shown), and is used for running and working of the wheel loader. The

  The controller 2 controls the driving of the work vehicle, and includes an electronic governor control means 3, a vehicle stop state judgment means 4, a work state judgment means 5, an inclination state judgment means 6, and a low rotation speed control means 7. .

  The rotation speed sensor 10 is provided in the engine 1 and detects the rotation speed of the engine 1.

  The electronic governor control means 3 is connected to the engine 1 and is supplied to the engine 1 in response to inputs from an operator (not shown), specifically an accelerator pedal, a brake pedal, an operation lever of a work implement, a speed stage control lever, and the like. The amount of fuel to be adjusted is adjusted to control the rotational speed of the engine 1.

  The electronic governor control means 3 controls the amount of fuel supplied to the engine 1 so that the rotational speed of the engine 1 is maintained at the standard idle rotational speed when driving of the traveling machine is interrupted. It is.

  The standard idle rotation speed of the work vehicle is such that the engine 1 is stable so that the engine does not stall even if the work vehicle is operated while the vehicle is stopped, considering that the work machine is driven to work even when the work vehicle is not traveling. The lower limit of the idling rotational speed that can be driven is set, specifically, higher than 50 rpm, for example, 700 to 800 rpm.

  The low rotation speed control means 7 is connected to the electronic governor control means 3 and has predetermined conditions based on signals input from a vehicle stop state determination means 4, a work state determination means 5 and an inclination state determination means 6 described later. In this case, a low idle rotation signal for controlling the amount of fuel supplied to the engine 1 is transmitted to the electronic governor control means 3 so that the rotation speed of the engine 1 is maintained at a low idle rotation speed.

  The low idle rotational speed is a rotational speed near the lower limit of the idle rotational speed at which the engine 1 can be stably driven, and is set to a speed lower than the standard idle rotational speed, for example, 50 to 200 rpm.

  The vehicle stop state determination means 4 is for determining the stop state of the work vehicle, and is connected to the low rotation speed control means 7 and is connected to the low rotation speed control means 7 in response to an input from a sensor or the like which will be described later. A stop signal is transmitted as will be described later.

  A water temperature sensor 11, a brake sensor 40, a speed sensor 41 and a timer 42 are connected to the vehicle stop state determination means 4.

  The water temperature sensor 11 sends a signal to the vehicle stop state determination means 4 when the water temperature of the engine 1 is equal to or higher than a predetermined water temperature.

  The brake sensor 40 transmits a signal to the vehicle stop state determination means 4 when a brake operation is performed.

  The speed sensor 41 considers that the vehicle has stopped when the speed of the work vehicle is equal to or lower than a predetermined speed, specifically, 0.1 km / h or less (including stopping), and determines whether the vehicle has stopped. A signal is sent to 4.

  The timer 42 measures the durations of the signals from the brake sensor 40 and the speed sensor 41. When the signals from these sensors continue for a predetermined time or longer, for example, 5 seconds or longer, a signal is sent to the vehicle stop state determination means 4 To send.

  The vehicle stop state determination means 4 receives a signal indicating that a signal is input from the water temperature sensor 11 and a signal indicating that the signals from the brake sensor 40 and the speed sensor 41 are input for a predetermined time from the timer 42. On the condition, a stop signal is transmitted to the low rotation speed control means 7.

  The work state determination means 5 is for determining interruption of the operation of the work machine, and is connected to the low rotation speed control means 7, and in response to an input from a sensor to be described later, A work interruption signal is transmitted as will be described later.

  A work machine operation sensor 50, a work machine position sensor 51, a work machine load sensor 52, and a steering operation sensor 53 are connected to the work state determination unit 5.

  The work machine operation sensor 50 transmits a signal to the work state determination means 5 when there is no input from an operation lever (not shown) or an operation pedal for operating the work machine.

  The work machine position sensor 51 transmits a signal to the work state determination means 5 when the work machine is in the neutral position, that is, when the bucket is in the neutral position.

  The work machine load sensor 52 transmits a signal to the work state determination unit 5 when there is no load on the work machine, specifically, when sandstone or the like is not held in the bucket.

The steering operation sensor 53 keeps the steering substantially straight within a predetermined range. Specifically, the steering is in a straight traveling state, or is turned within 10 degrees in the left-right direction with the straight traveling direction being 0 degrees. When the steering operation is not performed, a signal is transmitted to the work state determination means 5.

  The work state determination means 5 is connected to the low rotation speed control means 7 on condition that all signals from the work implement operation sensor 50, the work implement position sensor 51, the work implement load sensor 52, and the steering operation sensor 53 are input. On the other hand, a work interruption signal is transmitted.

  The inclination state determination means 6 is connected to the low rotation speed control means 7 and transmits a safe inclination signal to the low rotation speed control means 7 as described later in response to an input from a sensor described later.

  A forward / backward tilt sensor 60 and a left / right tilt sensor 61 are connected to the tilt state determination means 6.

  The front / rear tilt sensor 60 is provided in a main body of a work vehicle (not shown), measures the front / rear direction tilt of the work vehicle, and the work vehicle tilts back and forth within a predetermined tilt angle, for example, within 2.5 degrees. When the vehicle is in operation, it is determined that the work vehicle is at the front-rear reference position, and a signal is transmitted to the tilt state determination means 6.

  The predetermined inclination angle means that the work vehicle starts to slide down when the brake is released when the engine of the work vehicle is stopped or is stably idling around the limit rotational speed at which the engine does not stall. This is the limit tilt angle.

  The front-rear reference position refers to a state in which the work vehicle is assumed not to slide down forward or backward when the brake of the work vehicle in a stopped state is released.

  The left / right tilt sensor 61 is provided in a main body of a work vehicle (not shown), measures the tilt of the work vehicle in the left-right direction, and the work vehicle is within a predetermined tilt angle (including horizontal) within a predetermined tilt angle, for example, within 5 ° When the vehicle is tilting, the work vehicle is determined to be in the left / right reference position, and a signal is transmitted to the tilt state determination means 6.

  Inclination state determination means 6 is based on the condition that both the front and rear inclination sensors 60 and the left and right inclination sensors 61 are input, and the work vehicle has a reference in which the front and rear and left and right inclination angles are within a predetermined angle range. It is determined that the vehicle is in the position, and a safety tilt signal is transmitted to the low rotation speed control means 7.

  Next, the control state of the engine idle rotation speed in the above embodiment will be described with reference to FIG.

  FIG. 2 is a flowchart showing a control state of the idle rotation speed of the control device shown in FIG.

  When a vehicle stop operation (step 101) such as a brake operation is performed in the work vehicle, it is subsequently determined whether or not a vehicle start operation such as a brake release or an accelerator operation is performed (step 102).

  When there is a start operation, the idle rotation speed automatic control method according to the present invention ends.

  When there is no start operation, the electronic governor control means 3 controls the amount of fuel supplied to the engine 1 based on the detection information of the rotational speed sensor 10, and the rotational speed of the engine is maintained at the standard idle rotational speed (step 103). .

  Next, the low rotation speed control means 7 determines whether or not a stop signal is transmitted from the vehicle stop state determination means 4 (step 104).

  When no stop signal is transmitted from the vehicle stop state determination means 4, the stop of the work vehicle is returned to step 102 for determining the presence or absence of a start operation as a temporary stop during running and work.

  When a stop signal is transmitted from the vehicle stop state determination means 4, the low rotation speed control means 7 determines whether or not there is a work interruption signal from the work state determination means 5 (step 105).

  When no work interruption signal is transmitted from the work state determination means 5, the stop of the work vehicle is returned to step 102 for determining the presence or absence of a start operation as a stop while the work is continued.

  When a work interruption signal is transmitted from the work state determination means 5, the low rotation speed control means 7 determines whether or not there is a safe inclination signal from the inclination state determination means 6 (step 106).

  When there is no transmission of a safe tilt signal from the tilt state judging means 6, it is determined whether or not the start operation is performed as there is a risk of the work vehicle slipping down, engine stall, or engine drive instability when traveling is resumed. Return to step 102 for determination.

  When a safety inclination signal is transmitted from the inclination state determination means 6, the low rotation speed control means 7 sends a stop signal from the vehicle stop state determination means 4, a work interruption signal from the work state determination means 5, and an inclination state. Since the safety inclination signal is received from the determination means 6 and it is confirmed that all conditions for confirming the stop, work interruption and safety inclination of the work vehicle are satisfied, the low rotation speed control means 7 A low idle rotation signal is transmitted to the governor control means 3.

  The electronic governor control means 3 that has received the low idle rotation signal maintains the rotational speed of the engine 1 at a predetermined low idle rotational speed based on the rotational speed information of the engine 1 obtained by the rotational speed sensor 10. Thus, the amount of fuel supplied to the engine 1 is controlled, and the rotational speed of the engine 1 is maintained at a low idle rotational speed (step 107).

  When the rotation speed of the engine 1 is maintained at a low idle rotation speed, the presence or absence of changes in signals transmitted from the vehicle stop state determination means 4, the work state determination means 5 and the inclination state determination means 6 is continuously monitored (step 108). If there is no change, the rotational speed of the engine 1 continues to be maintained at a low idle rotational speed.

  When the rotational speed of the engine 1 is maintained at a low idle rotational speed, when there is a change in at least part of the signals transmitted from the vehicle stop state determination means 4, the work state determination means 5, and the lean state determination means 6. Returning to step 102 for determining the presence or absence of the start operation, the electronic governor control means 3 maintains the idle rotation speed of the engine 1 at the standard idle rotation speed when there is no start operation according to the presence or absence of the start operation.

  At this time, if there is a start operation, the control of the idle rotation speed itself is terminated, and the electronic governor control means 3 controls the rotation speed of the engine 1 according to the start operation.

  Next, based on FIG. 3, the relationship between the vehicle state in the working vehicle of the said Example and control of idle rotation speed is demonstrated.

  FIG. 3 is a pattern diagram showing the relationship between the vehicle state and the idle rotation speed of the control device shown in FIG.

  In this pattern diagram, when the vehicle state of the work vehicle is the condition above the double line, it is considered that the work vehicle is in a stopped state with work interruption and the vehicle tilt is also safe. Thus, the rotational speed of the engine 1 is maintained at a low idle rotational speed.

  Also, in this pattern diagram, when the vehicle state of the work vehicle is a condition below the double line, the work vehicle is not in a stop state with work interruption or is in such a stop state. However, if the rotational speed of the engine 1 is changed to a low idle rotational speed, it is assumed that there is a possibility that the engine 1 may slip down or become stalled at the time of restart, and the rotational speed of the engine 1 is maintained at the standard idle rotational speed. Or return to standard idle speed.

  Specifically, when a vehicle stop operation is performed, first, as a first stage, vehicle stop state determination means 4 performs 1) engine water temperature, 2) continuation of brake operation, 3) vehicle speed, and 4) Information regarding the brake operation and the duration of the vehicle speed below the predetermined speed is determined.

  When the water temperature of the engine 1 is equal to or lower than a predetermined water temperature, for example, immediately after the start of the engine 1 or at the time of overcooling, if the rotational speed of the engine 1 is reduced, the engine may be stalled. Since no signal is transmitted to the stop state determination means 4, the vehicle stop state determination means 4 does not transmit a stop signal.

  If a brake pedal (not shown) is depressed (brake operation) and the depressed time has not been maintained for a predetermined time, the operator's brake operation is not intended to stop the vehicle with work interruption. The vehicle stop state determination means 4 does not send a stop signal.

  When the brake operation is released in the stop signal transmission state, the work vehicle is regarded as starting, and the vehicle stop state determination means 4 stops transmitting the stop signal.

  When the vehicle speed exceeds the predetermined speed, the vehicle stop state determination means 4 does not send a stop signal.

  Even if the vehicle speed falls below the predetermined speed, if the state does not continue for a predetermined time, it is considered that the deceleration and stop of the work vehicle is not intended to stop the vehicle with work interruption. The vehicle stop state determination means 4 does not transmit a stop signal.

  As described above, when the stop signal is not transmitted, the rotational speed of the engine 1 is maintained at the standard idle rotational speed and is not changed to the low idle rotational speed.

  On the contrary, when all the conditions that the engine water temperature is higher than a predetermined water temperature and the brake operation is continued for a predetermined time or more and the vehicle speed below a predetermined speed is continued for a predetermined time or longer are satisfied, the vehicle stop state determination means 4 Since the work vehicle is stopped, a stop signal is transmitted to the low rotation speed control means 7.

  When a stop signal is transmitted from the vehicle stop state determination means 4, next, as a second stage, the work state determination means 5 performs 1) presence / absence of operation of a lever or pedal of the work implement, 2) position of the bucket 3) Bucket load state 4) Presence / absence of steering operation 5) Information on steering angle is determined.

  When a stop signal is transmitted from the vehicle stop state determination means 4, when a lever or pedal of a work machine (not shown) is operated, it is assumed that the work in the vehicle stop state is continuing, and the work state The determination means 5 does not transmit a work interruption signal.

  When the stop signal is transmitted from the vehicle stop state determination means 4, when the position of the bucket (not shown) is not in a predetermined neutral position, for example, when it is in the lift position, the vehicle stop state Assuming that the work is ongoing, the work state determination means 5 does not send a work interruption signal.

  When a stop signal is transmitted from the vehicle stop state determination means 4, when a load such as sandstone is held in a bucket (not shown), it is assumed that the operation in the vehicle stop state is continuing, The work state determination means 5 does not transmit a work interruption signal.

  When a stop signal is transmitted from the vehicle stop state determination means 4 and a steering (not shown) is operated, it is assumed that the operator intends to move the work vehicle, and the work state determination means 5 Do not send work interruption signal.

  When a stop signal is transmitted from the vehicle stop state determination means 4, if the steering angle (not shown) is outside the range of a predetermined angle, the engine stalls when traveling or returning to work if the idle rotation speed is reduced. Since there is a possibility, the work state determination means 5 does not transmit a work interruption signal.

  As described above, when the work interruption signal is not transmitted, the rotational speed of the engine 1 is maintained at the standard idle rotational speed and is not changed to the low idle rotational speed even while the stop signal is transmitted.

  On the contrary, when all the conditions such as no operation of the working machine lever or pedal, the bucket in the neutral position, the bucket is empty, the steering operation is not performed, and the steering angle is within the predetermined angle range, the working state determination means 5 transmits a work interruption signal to the low rotation speed control means 7 assuming that the work is interrupted.

  When a stop signal is transmitted from the vehicle stop state determination means 4 and a work interruption signal is transmitted from the work state determination means 5, next, as a third step, the inclination state determination means 6 Information regarding 1) the tilt angle in the front-rear direction and 2) the tilt angle in the left-right direction is determined.

  When a stop signal is transmitted from the vehicle stop state determination means 4 and a work interruption signal is transmitted from the work state determination means 5, the front and rear inclination sensor 60 allows the inclination angle in the front-rear direction of the work vehicle to be within a predetermined range. If the idling speed is reduced and the brake operation is released when the vehicle is returned to the traveling state, the work vehicle may slide down, so that the inclination state determination means 6 does not transmit a safety inclination signal.

  When a stop signal is transmitted from the vehicle stop state determination means 4 and a work interruption signal is transmitted from the work state determination means 5, the left / right inclination sensor 61 allows the inclination angle of the work vehicle in the left-right direction to be within a predetermined range. Is exceeded, it is assumed that the driving force is required as in camper travel, and if the idling speed is reduced, engine stall may occur at the time of travel recovery. The means 6 does not transmit a safety tilt signal.

  As described above, when the safety tilt signal is not transmitted, the rotation speed of the engine 1 is maintained at the standard idle rotation speed and is not changed to the low idle rotation speed even while the stop signal and the work interruption signal are continuously transmitted.

  On the contrary, when all the conditions that the tilt angle in the front-rear direction and the left-right direction are within the predetermined angle range are satisfied, the tilt state determination unit 6 determines that the tilt angle of the work vehicle is safe, Send a safety tilt signal.

  The low rotational speed control means 7 is used when the stop signal, the work interruption signal, and the safety inclination signal are continuously input from the vehicle stop state determination means 4, the work state determination means 5 and the inclination state determination means 6. 3, the low idle rotation signal for changing the rotation speed of the engine 1 from the standard idle rotation speed to the low idle rotation speed only when all the conditions shown above the double line in the pattern diagram of FIG. 3 are satisfied. Until the input state of each signal indicating the vehicle state is changed, the rotational speed of the engine 1 is maintained at a low idle rotational speed.

  The automatic idle speed control method for a work vehicle engine according to the present invention is configured as described above. Therefore, according to the present invention, when traveling or resuming work, the work vehicle slides down, the engine stalls, the engine. Only when there is no possibility of driving instability or the like, the idle rotation speed of the engine 1 can be reduced when the work vehicle is stopped with work interruption, so that fuel is saved without sacrificing safety. And noise and vibration can be reduced.

  Next, another embodiment of the idle speed automatic control device for the working vehicle engine according to the present invention will be described.

  Since the main configuration and operation of this embodiment are the same as those in [Embodiment 1], the description will focus on the differences.

  In this embodiment, the tilt state determination means 6 determines whether the left and right tilt angles are within a predetermined angle range, and whether the work vehicle is in the rearward tilt position.

  The backward tilt position refers to a state where the work vehicle is tilted at an angle that is expected to slide backward when the brake of the stopped work vehicle is released, and the work vehicle is stopped without sliding backward. As an inclination angle that is a limit for maintaining the angle, for example, 3 degrees can be mentioned.

  In this embodiment, based on the tilt information of the work vehicle input from the front / rear tilt sensor 60 and the left / right tilt sensor 61, when the tilt state in the front / rear direction of the work vehicle is not the rearward tilt position, and the tilt in the left / right direction When the state is the left / right reference position, the tilt state determination unit 6 transmits a safe tilt signal to the low rotation speed control unit 7.

  Further, at least when the work vehicle is tilted back and forth in the front-rear direction or the right-and-left direction is not the left-right reference position, the incline determination unit 6 sends a safe incline signal to the low rotation speed control unit. Do not send.

  According to this embodiment, the rotational speed of the engine 1 is maintained at a low idle rotational speed even when the forward / backward tilt state is not the rearward tilt position, that is, even when the work vehicle slides forward by releasing the brake. The

  In this embodiment, the reason why the low idle rotation speed is maintained even in the situation where the work vehicle slides forward is basically that when the work vehicle returns to the running state from the stop state with work interruption. In order to drive the work vehicle forward, the operator does not feel unnaturalness even when the work vehicle slides forward as the brake is released, and the ground where the work vehicle is stopped is When the vehicle is tilted so that the front is lowered, the vehicle weight of the work vehicle acts in the traveling direction. Therefore, when driving is resumed, a large driving force is not required, and the engine 1 is not burdened when the traveling is resumed. This is because there is no safety problem in maintaining the rotational speed of the engine 1 at a low idle rotational speed even in a situation where it slides forward.

  According to this embodiment, the idle rotation speed of the engine 1 can be reduced within a range that does not cause a safety problem, so that fuel can be saved and noise and vibration can be reduced.

  Next, another embodiment of the idle speed automatic control device for the working vehicle engine according to the present invention will be described.

  Since the main configuration and operation of this embodiment are the same as those in [Embodiment 1], the description will focus on the differences.

  In this embodiment, the inclination state determination means 6 determines whether the work vehicle is in any inclination state among the front and rear reference position, the forward inclination position, and the rearward inclination position, and whether the left and right inclination angles are the left and right reference positions. Judge whether or not.

  The forward lean position refers to a state where the work vehicle is tilted at an angle that is expected to slide forward when the brake of the stopped work vehicle is released, and the work vehicle is stopped without sliding forward. As an inclination angle that is a limit for maintaining the angle, for example, 3 degrees can be mentioned.

  In this embodiment, the lean state determination means 6 or the low rotation speed control means 7 uses the rotation speed of the engine 1 at the forward lean position of the work vehicle as the standard idle rotation speed or the low idle rotation speed. Switching means for selecting whether or not is provided.

  In this embodiment, the rotational speed of the engine 1 is changed to the standard idle speed when the work vehicle is in the forward tilt position by changing the setting of the lean state determination means 6 or the low rotational speed control means 7 according to the use situation. It is possible to select whether to maintain at a speed or to maintain at a low idle rotation speed.

  For example, if the forward lean position is excluded from the low idle rotation speed condition, the work vehicle is determined to be the front / rear reference position and the left / right reference position based on the lean information of the work vehicle input from the front / rear tilt sensor 60 and the left / right tilt sensor 61. In this case, the tilt state determination unit 6 transmits a safe tilt signal to the low rotation speed control unit 7.

  Further, for example, when the forward lean position is included in the condition of the low idle rotation speed, the work vehicle is moved to the forward / backward reference position or the forward lean position based on the lean information of the work vehicle input from the forward / backward tilt sensor 60 and the left / right tilt sensor 61. In the case of the left / right reference position, the tilt state determination means 6 transmits a safe tilt signal to the low rotation speed control means 7.

  In this embodiment, it is possible to set whether or not to allow the vehicle to slide forward when resuming traveling according to the work environment and user needs, so that further fuel saving and noise and vibration reduction can be achieved. Will be able to.

  Next, another embodiment of the idle speed automatic control device for the working vehicle engine according to the present invention will be described.

  Since the main configuration and operation of this embodiment are the same as those of [Embodiment 3], the description will focus on the differences.

  In this embodiment, the tilt state determination means 6 calculates the tilt angle of the tilt plane where the work vehicle is stopped based on the obtained tilt angles in the front-rear direction and the left-right direction, and the tilt of the obtained tilt plane is calculated. The inclination state of the work vehicle is determined based on the angle.

  This inclined plane is a substantially plane including, for example, a straight line connecting the ground contact points of the front wheels of the work vehicle and a straight line connecting the ground contact points of the rear wheels.

  Further, in this embodiment, it is determined whether or not the work vehicle is in a tilted state, that is, a tilted state with a sliding down, based on the tilt plane. A control limit value is set for the inclination angle obtained from 61.

  This control limit value is, for example, even in the case of a forward tilt position, the forward tilt angle is an extremely large tilt angle, for example, at least 3 degrees or more, 10 degrees or more on the left and right, and 5 degrees or more on the tilt plane. When the vehicle is inclined beyond one or more types of inclination angles, the engine 1 is not controlled at a low idle rotational speed in order to prevent the vehicle from falling down. The tilt angle obtained from the left / right tilt sensor 61 and the obtained tilt plane are provided respectively.

  Further, in this embodiment, the low rotational speed control means 7 is set as a low idle rotational speed, in addition to the normal low idle rotational speed, a two-stage speed of engine pause is set. Accordingly, the control for maintaining the low idle rotation speed of the engine 1 or the temporary stop of the engine can be commanded.

  The engine is temporarily stopped, for example, when the forward / backward tilt state of the work vehicle is in the forward tilt position.

  In this embodiment, when the engine is temporarily stopped and the brake is released, the work vehicle starts to slide forward. However, since the sliding direction coincides with the start direction, immediately after the start operation. A powerful driving force is not required.

  For this reason, in the case of the above-mentioned stop state, even if the driving of the engine 1 is temporarily stopped, no safety problem occurs.

  According to the above embodiment, since it is possible to perform control to reduce the engine idle speed without sacrificing safety, it is possible to effectively save fuel consumption and reduce noise and vibration. Is.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the work vehicle is a wheel loader, but the output of the engine is distributed to the traveling machine and the work machine and driven. It is good also as another work vehicle, for example, an off-road dump.

  In this case, the work machine corresponding to the bucket is a vessel, and when the work is judged to be suspended, the vessel is in the “up” position, and when the vessel is loaded with sandstone or the like, the work is stopped. It is assumed that it is ongoing.

  In addition, with a wheel loader, the vehicle stop state with work interruption may be waiting for an empty dump, etc.In the case of an off-road dump, the operator is on duty or is operated unattended according to a remote operation or operation program. For example, in order to ensure safety, the off-road dumping may be stopped in order to wait for the obstacle vehicle to pass or to prevent contact with an obstacle.

  In addition, the conditions for executing the control at the low idle rotation speed, specifically, the engine water temperature, the duration of the stop state, the duration of the brake operation, the vehicle speed regarded as the stop state, the vehicle inclination angle, etc. The present invention is not limited to the above-described embodiment, and can be freely changed according to the type, size, and usage environment of the work vehicle.

  Further, in the above embodiment, when judging the vehicle state, the judgment is made in the order of stillness, work interruption, and safety inclination, but the order is not limited to this, and all judgments should be made simultaneously. It may be.

  Further, the controller or the low rotational speed control means receives a signal directly from the sensor for detecting the state of the work vehicle, determines the state of the work vehicle, and sends a signal for controlling the rotational speed of the engine to the low rotational speed control means. You may make it transmit.

  INDUSTRIAL APPLICABILITY The present invention is useful in terms of fuel consumption, exhaust gas amount, noise and vibration reduction of a work vehicle having a special configuration such as a wheel loader or an off-road dumper among work vehicles. Probability is high.

DESCRIPTION OF SYMBOLS 1 Engine 10 Rotational speed sensor 11 Water temperature sensor 2 Controller 3 Electronic governor control means 4 Vehicle stop state judgment means 40 Brake sensor 41 Speed sensor 42 Timer 5 Work state judgment means 50 Work machine operation sensor 51 Work machine position sensor 52 Work machine load sensor 53 Steering operation sensor 6 Inclination state determination means 60 Front / rear inclination sensor 61 Left / right inclination sensor 7 Low rotational speed control means

Claims (7)

An idle speed automatic control method for an engine for a work vehicle in which the output of the engine is distributed to the traveling machine and the work machine, and the idle engine is determined so that the engine does not stall even if the work vehicle performs work while the work vehicle is stopped. The engine rotates at an idle speed at a standard idle speed set higher than near the lower limit of the idle speed at which the engine can be driven stably.
a) determining a stop state of the work vehicle, determining interruption of operation of the work machine, and determining a tilt state of the work vehicle;
b) It is determined that the work vehicle is stopped, the operation of the work machine is interrupted, the work vehicle is tilted, the tilt angle in the front-rear and left-right directions, and the engine is idling at a low idle speed. when the brake of the working vehicle when that is the reference position the working vehicle when it is open is in the range of a predetermined angle is the angle limit begins to fall shear, the idle speed of the engine, the standard the idle rotation speed, the engine is a stable rotational speed of the lower vicinity of the idling rotational speed may drive and control for maintaining and changing the than the standard idle rotation speed to the low idle rotation speed of the low rotational A step of performing
The method for automatically controlling the idle rotation speed of the engine for a work vehicle as described above. In the idling rotational speed automatic control method of the engine for work vehicles according to claim 1,
It is determined that stop of the working vehicle, and a determination is made as interruption of work machine operation, and the inclined state of the lateral direction of the working vehicle, wherein a lateral reference position is within a predetermined angular range, and the working vehicle the inclination angle of the longitudinal direction, when it is not tilted position after the rear decreases beyond the predetermined angle range, the control for maintaining the idling rotational speed of the engine to the low idle rotation speed of the low rotational than the standard idle speed The method for automatically controlling an idle speed of an engine for a work vehicle as described above. An inclination angle of an inclined plane on which the work vehicle is stopped is calculated based on an inclination angle of the work vehicle in the front-rear direction and the left-right direction, and the inclination state of the work vehicle is determined based on the inclination angle of the inclination plane. Item 3. An automatic idle speed control method for a work vehicle engine according to Item 1 or 2. When the rotational speed of the engine is maintained at the low idle rotation speed, of the operation of the brake release and the working machine, when at least one has been executed, the control for maintaining the rotational speed of the engine in the low idle speed The method for automatically controlling the idle viewpoint speed of the work vehicle engine according to any one of claims 1 to 3. 5. The engine for a work vehicle according to claim 1 , wherein the engine is stopped instead of the low idle rotation speed when the forward / backward tilt state of the work vehicle is a forward lean position. Automatic rotation speed control method. 6. The work vehicle according to claim 1, wherein a plurality of idle rotation speeds including the low idle rotation speed and engine stop are set, and the plurality of idle rotation speeds are selected according to the inclination of the work vehicle. Engine idle speed automatic control method. 7. An idle speed automatic control method for a work vehicle engine according to claim 1, wherein the vehicle stop state determination means, the work state determination means, the tilt state determination means, and the engine idle rotation speed are used. the idle speed automatic control device for a working vehicle engine, comprising a low rotational speed control means for controlling to the low idle rotation speed.

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