JPH11324023A - Engine control method for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimally reduce the raising frequency of an engine power to improve fuel consumption by outputting an instruction signal to raise the engine power when a lifting operation signal for a working machine is input in a control system. SOLUTION: A working machine moved up and down by a hydraulic cylinder, a hydraulic pump for supplying hydraulic oil to the hydraulic cylinder, and an electronic control engine 33 for driving the hydraulic pump are mounted on a vehicle body. When an operating lever signal 51 for raising a boom is input to actuate the hydraulic cylinder and raise upward the working machine, in a controller 56 controlling the motion of the hydraulic cylinder, an instruction signal is output to raise the engine power to the electronic control engine 33. Hence, only when a working quantity is required to increase, the engine power is increased and the raising frequency of the engine power can be minimally reduced to improve the fuel consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an engine in a vehicle.

[0002]

2. Description of the Related Art As shown in FIG. 6, a hydraulic excavator includes a lower traveling body 13 having a crawler belt 12 driven by a pair of left and right traveling hydraulic motors 11 of a traveling system. Via the slewing bearing 15 driven by
An upper rotating body 16 is provided so as to be freely rotatable.
In addition, a cab 17 provided with an operator's driver's seat and a front work machine 18 for excavation work are provided. The lower traveling body 13 and the upper revolving superstructure 16 constitute a vehicle main body.

[0003] A front work machine 18 is provided with a pin
The boom 20 is rotatably supported by 19, and this boom 20
A stick 22 is rotatably supported at the tip of the stick 22 by a pin 21, and a bucket 24 is
Are rotatably supported.

The boom 20 is a boom hydraulic cylinder.
25, the stick 22 is moved up and down about the pin 19 as a fulcrum, the stick 22 is moved up and down about the pin 21 as a fulcrum by the hydraulic cylinder 26 for the stick, and the bucket 24 is moved up and down about the pin 23 as a fulcrum by the hydraulic cylinder 27 for the bucket and the link mechanism 28. You.

The upper revolving unit 16 of the vehicle body includes a tank 30 containing hydraulic oil for a hydraulic circuit, left and right traveling hydraulic motors 11, a turning hydraulic motor 14, and hydraulic cylinders 25 of a front working machine 18, respectively. A pair of main hydraulic pumps 31 for supplying hydraulic oil to 26 and 27, a pilot hydraulic pump 32, and an engine 33 for driving these hydraulic pumps 31 and 32 are mounted. The conventional engine 33 is generally an engine with a mechanical governor controlled by a mechanical governor.

Further, the hydraulic excavator is provided with a control system 34 for controlling the operations of the left and right traveling hydraulic motors 11, the turning hydraulic motor 14, and the hydraulic cylinders 25, 26, 27 of the front working machine 18. .

The control system 34 controls the operating oil supplied from the main hydraulic pump 31 to the left and right traveling hydraulic motors 11, the turning hydraulic motor 14, and the hydraulic cylinders 25, 26, 27 of the front working machine 18. The control valve 35 includes a control valve 35 for controlling and controlling the flow rate, a pilot valve 36 for remotely controlling the control valve 35 by a pilot hydraulic pressure supplied from the pilot hydraulic pump 32, and a hydraulic line for connecting these pipes.

The control valve 35 is provided outside the cab 17 and controls a left traveling control stem 37 for controlling the left traveling hydraulic motor 11 and a right traveling control for controlling the right traveling hydraulic motor 11. A control stem 38, a turning control stem 39 for controlling the turning hydraulic motor 14, a boom control first stem 41 and a second stem 42 for controlling the boom hydraulic cylinder 25, a stick hydraulic Cylinder
A first stem 43 and a second stem 44 for stick control for controlling the cylinder 26, a stem 45 for bucket control for controlling the hydraulic cylinder 27 for bucket, and a stem 37 for left traveling control from one main hydraulic pump 31. And a straight traveling control stem 46 for supplying hydraulic oil only to the right traveling control stem 38 to drive the left and right traveling hydraulic motors 11 at a constant speed.

The pilot valve 36 is provided inside the cab 17 and is manually operated by an operator in the cab 17 with an operation lever 47 to control the pressure of the pilot pressure oil supplied from the pilot hydraulic pump 32 so as to reduce the pressure. Each stem 37, 3
8, 39, 41, 42, 43, 44 and 45 are constituted by a number of pressure reducing valves 48 (hereinafter, these pressure reducing valves are referred to as "remote control valves") 48 for supplying pressure chambers at both ends.

In a conventional hydraulic excavator, the load pressure is detected, and when the load pressure exceeds a certain value, it is determined that the load is heavy, and the set pressure of the hydraulic oil discharged from the main hydraulic pump 31 is increased or the mechanical governor is used. The engine 33 to be controlled is provided with an additional mechanism to increase the engine horsepower, and by adjusting to increase the engine speed set by the mechanical governor, the engine horsepower is increased to increase the work load under heavy load. Is increasing.

[0011]

As described above, conventionally,
Since the load state is determined only by the pressure, the frequency of the engine speed and the engine horsepower increase more frequently, for example, not only when the pressure in the boom hydraulic cylinder 25 rises but also in the stick hydraulic cylinder 26 when the pressure rises. Judging that the engine is heavy, the engine speed increases frequently, so fuel efficiency often deteriorates.In addition, the increase in engine speed also causes problems such as an increase in noise, a decrease in engine life, and a decrease in pump life. .

In order to increase the running force of the running hydraulic motor 11, the engine horsepower is increased by increasing the engine speed of the engine 33 controlled by the mechanical governor. Fuel economy often deteriorates, and there are problems such as an increase in noise due to an increase in engine speed and a reduction in life.

The present invention has been made in view of the above points, and increases the engine horsepower only when it is really needed, thereby increasing the amount of work or running ability, and improving fuel efficiency, noise and noise. The purpose is to improve the life.

[0014]

According to a first aspect of the present invention, there is provided a working machine vertically moved by a hydraulic cylinder to a vehicle body, a hydraulic pump for supplying hydraulic oil to the hydraulic cylinder of the working machine, In a vehicle equipped with an engine that drives the hydraulic pump and a control system that controls the operation of the hydraulic cylinder of the work machine, a work machine lift that operates the hydraulic cylinder in a direction to raise the work machine input to the control system This is an engine control method for increasing the engine horsepower by an operation signal.

Accordingly, the condition for increasing the engine horsepower is set when a specific work implement raising operation signal is input to the control system, and the engine horsepower is increased only when it is necessary to increase the amount of work. Minimizing the frequency with which engine horsepower rises can improve fuel economy.

According to a second aspect of the present invention, there is provided a hydraulic pump for supplying hydraulic oil to a hydraulic motor of a traveling system, to a vehicle body having a traveling system including a hydraulic motor, and an engine for driving the hydraulic pump. In a vehicle equipped with a control system for controlling the operation of the hydraulic motor of the traveling system, the traveling pressure generated in the hydraulic motor of the traveling system and the traveling operation for operating the hydraulic motor of the traveling system input to the control system This is an engine control method for increasing the engine horsepower in response to an increase in a signal.

Thus, it is necessary to set the condition for increasing the engine horsepower when the running pressure is increased to a certain value and a running operation signal of a certain value or more is input to the control system to increase the running capacity. Since the engine horsepower is increased only when there is, the frequency at which the engine horsepower increases can be minimized and the fuel efficiency can be improved.

According to a third aspect of the present invention, there is provided the engine control method for a vehicle according to the first or second aspect, wherein the increase in the engine speed is limited and the engine horsepower is increased.

Even if the engine horsepower is increased, the increase in the engine speed is limited, so that the noise and the life can be improved.

According to a fourth aspect of the present invention, there is provided the vehicle control method according to any one of the first to third aspects, wherein an electronically controlled engine is mounted on the vehicle body, and the engine horsepower of the electronically controlled engine is reduced. It is an engine control method to raise.

By using an electronically controlled engine, only the engine horsepower can be directly increased without the need for an additional mechanism for increasing the engine horsepower as in an engine controlled by a mechanical governor.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to one embodiment shown in FIGS. 1 to 3, another embodiment shown in FIG. 4, and still another embodiment shown in FIG. This will be described with reference to embodiments. The hydraulic excavator and its hydraulic circuit shown in FIG. 6 are also used in the description of the present invention.

That is, as shown in the hydraulic excavator shown in FIG. 6, a front work machine 18 vertically moved by a boom hydraulic cylinder 25 is mounted on an upper revolving unit 16 of a vehicle body, and a left and right traveling system of a traveling system. A pair of main hydraulic pumps 31 for supplying hydraulic oil to the hydraulic motor 11, the turning hydraulic motor 14, and the boom hydraulic cylinder 25 of the front working machine 18, a pilot hydraulic pump 32, and these hydraulic pumps 31, 32 are driven. And a control system 34 for controlling the operation of the hydraulic cylinders 25, 26, 27 of the front work machine 18, etc., as in the prior art.

On the other hand, the engine 33 is an electronic control engine (hereinafter referred to as an "electronic control engine 33") capable of electronically controlling the engine horsepower. The electronic control engine 33 controls the main hydraulic pump 31 and the pilot hydraulic pressure. The point that the pump 32 is driven is different from the conventional one.

FIG. 1 is a block diagram of an engine control system for increasing the engine horsepower of the electronic control engine 33. The electronic control engine 33 includes a boom raising operation lever signal 51 as a work implement raising operation signal and other related signals. An operation lever signal 52, a system pressure 53, an engine speed 54, and an on / off switching signal 55 are controlled by a controller 56 that has performed a logical operation as an input signal.

The boom raising operation lever signal 51 is transmitted to the cab 17
The operation of the operation lever 47 of the boom remote control valve 48 for controlling the operation of the boom hydraulic cylinder 25 in the boom raising direction is performed at a fixed position by a limit switch or at an arbitrary position by a potentiometer. Detect and input to controller 56.

The operator also operates the operation lever 47 of the remote control valve 48 for controlling the operation of the hydraulic motor 14 for turning, the hydraulic cylinder 26 for sticks or the hydraulic cylinder 27 for buckets. The operation is detected at a fixed position by a limit switch or the like at an arbitrary position by a potentiometer or the like, and is input to the controller 56.

As the system pressure 53, for example, a load pressure applied to the bucket hydraulic cylinder 27 is detected by a pressure switch or a pressure sensor or the like, and is input to the controller 56.

The engine speed 54 is an engine speed set by, for example, an accelerator dial.

The ON / OFF switching signal 55 is a signal from a switch for determining whether to execute or stop the main control, that is, the control for increasing the engine horsepower during the boom raising operation.

The logic operation controller 56 determines whether or not each input signal satisfies the condition. If the condition is satisfied, the controller 56 instructs the electronic control engine 33 to increase the engine horsepower. Output a signal.

As shown in FIG. 2, an electronic control engine
33 has an engine electronic module 57 and an electronic unit injector 58.The engine electronic module 57 uses a control signal from a controller 56 and various signals from various sensors 61, a speed sensor 62 and a throttle 63,
The electronic unit injector 58 is controlled.

As shown in FIG. 3, the electronic control engine 33 has a number of engine speed-engine horsepower (torque) curves A and B by software (personality module) prepared in an engine electronic module 57. , C can be realized, and an arbitrary engine horsepower curve can be selected by an external signal.

Thus, in a state where the increase in the engine speed is limited, for example, even when the engine speed is constant,
Engine horsepower can be increased. Moreover, only the engine horsepower can be directly increased without the need for an additional mechanism for increasing the engine horsepower unlike a conventional engine controlled by a mechanical governor.

Next, one control example in the embodiment shown in FIGS. 1 to 3 will be described.

Only when the boom raising operation is performed, it is desired to increase the engine horsepower under certain conditions to effectively increase the amount of work.
In other cases, a normal engine horsepower set will provide sufficient work.

Under certain conditions, for example, the boom raising operation lever signal 51 is fully operated, the bucket pressure as the system pressure 53 is equal to or higher than a certain load pressure, and the engine speed 54 set by the accelerator dial or the like. Is full rotation.

Only when these conditions are satisfied, the state is determined by the logical operation controller 56, and a signal for increasing the engine horsepower is sent to the engine electronic module 57 of the electronic control engine 33. To improve work efficiency.

In this control, when performing other operations related to the boom raising operation together with the boom raising operation,
The operation lever signal 52 other than the boom can also be one of the conditions for increasing the engine horsepower.

For example, when there is a turning operation by an operating lever of a turning remote control valve for controlling the operation of the turning hydraulic motor 14 in addition to the boom raising operation, or when the boom raising operation and this turning operation are performed. In addition, if there was a stick operation or a bucket operation with the operation lever of the stick or bucket remote control valve for controlling the operation of the stick hydraulic cylinder 26 or the bucket hydraulic cylinder 27, the state was also determined by logical operation. The controller 56 controls the engine horsepower of the electronic control engine 33 so as to increase the engine horsepower without increasing the engine speed, thereby improving work efficiency.

As described above, by controlling the engine horsepower to be increased by the boom raising operation lever signal input to the control system for operating the hydraulic cylinder in the direction of raising the working machine, and other related operation lever signals. ,
In a work requiring a really large amount of engine horsepower, the work amount can be increased.

In other words, the condition for increasing the engine horsepower is set when a specific work implement raising operation signal is input to the control system, and the boom raising operation requiring a large amount of engine horsepower and other related operations are set. The engine horsepower can be increased only when the engine horsepower is increased, and the amount of work can be increased, and the engine fuel efficiency can be improved by minimizing the frequency at which the engine horsepower increases.

Also, by using the electronically controlled engine 33, the engine speed is not increased even when the engine horsepower is increased, so that engine noise can be reduced and the life of the hydraulic pumps 31, 32 and the engine 33 can be extended. .

FIG. 4 shows a modification in which the embodiment shown in FIGS. 1 to 3 is the simplest form, in which the electronic control engine 33 is controlled only by the boom raising operation lever signal 51.

In this case, the controller 56 for the logical operation is not necessary, and the boom raising operation lever signal 51 is electrically picked up by a sensor such as a limit switch and a potentiometer provided on the boom operation lever 47, and the boom raising operation signal is picked up. Raise the operating lever signal 51 directly to the electronically controlled engine
It is sent to the 33 engine electronic module 57 to control the engine horsepower to increase.

At this time, the method of increasing the engine horsepower may be such that the engine horsepower can be increased stepwise at two positions or continuously increased.

Next, FIG. 5 is a block diagram showing an embodiment of an engine control system for controlling the engine horsepower of the electronic control engine 33 according to the running situation. In this case, when the normal horsepower setting is sufficient, the same control as in the case of the boom raising operation is performed.

The electronic control engine 33 generates a travel operation lever signal 71 as a travel operation signal input to the control system 34.
And a traveling pressure 72 which is a system pressure generated in the traveling system,
The engine speed 54 and the on / off switching signal 55 are subjected to logical operation processing by the controller 56, and the electronic control engine
Control 33.

The travel operation lever signal 71 indicates the amount of manual operation of the operation lever 47 of the travel remote control valve 48 by the operator in the cab 17 to control the operation of the pair of left and right travel hydraulic motors 11. Detected by a sensor such as a potentiometer and input to the controller 56.

The running pressure 72 is input to the controller 56 by detecting the load pressure applied to each running hydraulic motor 11 by a pressure switch or a pressure sensor or the like.

Then, the controller 56 increases the engine horsepower in accordance with the increase in the traveling operation lever signal 71 and the traveling pressure 72.

That is, when the running load exceeds a certain value during running and the operating lever for running is operated larger than a certain position, for example, when the lower running body 13
In such a case, the controller 56 controls the electronic control engine 33 to increase only the engine horsepower without increasing the engine speed. This allows
Work efficiency can be increased, and the amount of work can be increased.

As described above, when the traveling pressure 72 increases to a certain value and the traveling operation lever signal 71 which is equal to or more than the predetermined value is input to the control system, if the condition is set so that the engine horsepower is increased, the traveling becomes true. The engine horsepower can be increased only when it is necessary to increase the performance, and the frequency of the engine horsepower increasing can be minimized to improve fuel efficiency.

At the same time, by using the electronically controlled engine 33, the engine speed is not increased even when the engine horsepower is increased, so that the engine noise can be reduced and the environment is improved due to a small change in the engine speed. And the life of the hydraulic pumps 31, 32 and the engine 33 can be extended.

In the illustrated embodiment, the electronic control engine 33 has been described. However, in an engine with a mechanical governor controlled by the mechanical governor, two types of engine horsepower can be selected without increasing the rated engine speed. There is something you can do. In other words, there is an engine with a mechanical governor that can change the governor fuel set in two stages using an electromagnetic valve.
Such a horsepower set two-stage engine with a mechanical governor may be used.

In the illustrated embodiment, the case of a hydraulic excavator has been described. For example, in the case of a truck type loader or the like, the same control is performed for the lifting operation of the lift arm and the running operation of the crawler belt. And good. Further, the present invention can be applied to other construction machines and vehicles other than the construction machines in the working machine system or the traveling system.

[0057]

According to the first aspect of the present invention, it is necessary to increase the amount of work by setting the condition for increasing the engine horsepower when a specific work implement raising operation signal is input to the control system. Since the engine horsepower is increased only at certain times, it is possible to secure an increase in the amount of work required for the work involving the work implement raising operation, and to minimize the frequency at which the engine horsepower increases, thereby improving fuel efficiency.

According to the second aspect of the present invention, the condition for increasing the engine horsepower is set when the traveling pressure increases to a certain value and a traveling operation signal of a certain value or more is input to the control system, Since the engine horsepower is increased only when it is necessary to increase the traveling capacity, it is possible to secure the traveling capacity required for traveling on a rough road or the like, and to minimize the frequency at which the engine horsepower increases, thereby improving fuel efficiency.

According to the third aspect of the present invention, even if the engine horsepower is increased, the increase in the engine speed can be limited, so that the noise and the life can be improved.

According to the fourth aspect of the present invention, the use of the electronically controlled engine eliminates the need for an additional mechanism for increasing the engine horsepower, unlike an engine controlled by a mechanical governor, and reduces only the engine horsepower. Can be raised directly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an engine control system used in an engine control method according to the present invention.

FIG. 2 is a block diagram showing a horsepower control unit of the electronic control engine used in the engine control method.

FIG. 3 is a characteristic diagram showing an engine speed-engine horsepower curve in the electronic control engine.

FIG. 4 is a block diagram showing another embodiment of the engine control system of the same.

FIG. 5 is a block diagram showing still another embodiment of the engine control system.

FIG. 6 is an explanatory view schematically showing a hydraulic excavator according to the present invention and a hydraulic circuit thereof.

[Explanation of symbols]

11 Hydraulic motor of traveling system 18 Work implement 25 Hydraulic cylinder 31 Hydraulic pump 33 Electronic control engine 34 Control system 51 Boom raising operation lever signal as work equipment raising operation signal 71 Traveling operation lever signal as traveling operation signal 72 Traveling pressure

Claims (4)

[Claims] A work machine mounted on a vehicle body, the work machine being moved up and down by a hydraulic cylinder, a hydraulic pump for supplying hydraulic oil to a hydraulic cylinder of the work machine, and an engine for driving the hydraulic pump; A vehicle equipped with a control system for controlling the operation of a hydraulic cylinder, wherein the engine horsepower is increased by a work machine raising operation signal input to the control system and operating the hydraulic cylinder in a direction to raise the work machine. Engine control method. 2. A vehicle body provided with a traveling system including a hydraulic motor, a hydraulic pump for supplying hydraulic oil to the traveling system hydraulic motor, and an engine for driving the hydraulic pump are mounted. In a vehicle equipped with a control system for controlling the operation of the motor, a travel pressure generated in the hydraulic motor of the travel system and a travel operation signal input to the control system for operating the hydraulic motor of the travel system are increased. An engine control method for a vehicle, wherein the engine horsepower is increased. 3. The engine control method for a vehicle according to claim 1, wherein the increase in engine speed is limited and the engine horsepower is increased. 4. An electronically controlled engine mounted on a vehicle body,
4. The engine control method according to claim 1, wherein the engine horsepower of the electronic control engine is increased.