JPH0533701A - Engine speed control method for construction machine, and device therefor - Google Patents

Abstract

PURPOSE:To provide a method of sufficiently reducing the low noise and attaining a low fuel consumption rate effect by minimizing the number of revolutions during automatic idling operation. CONSTITUTION:The amount of operation of an actuator 3 is determined via a controller 2 by the voltage outputted from a throttle setting switch 1. The movement of the actuator 3 is interlocked with a control lever 5 attached to an injection pump of an engine 4 so as to increase or decrease the fuel injection quantity in accordance with the rotating angle of the control lever 5. In this way, the set number of revolutions during automatic idling operation is automatically changed in corresponding relation to the number of engine revolutions set at the time of starting the operation, thereby bringing the engine to a condition of low-speed revolution.

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 speed in a construction machine and an apparatus for carrying out this method.

[0002]

2. Description of the Related Art When a construction machine such as a hydraulic excavator is used for work such as excavation and loading, a work pause time such as a wait for a dump occurs between works. During this downtime, noise is reduced and the engine is automatically turned to a low speed for the purpose of improving fuel efficiency.
Toidol (auto decel) is generally known.

It takes some time for the engine to be released from the low speed of the auto idle and rise to the maximum speed. If this time is long, a large response delay and speed fluctuation will occur in the actuator, which will hinder the work. For this reason, in the conventional example, when the maximum engine speed to be used is determined, the auto idle rotational speed is determined within a range in which a large response delay does not occur even if the maximum engine speed is increased. As a result,
The idle speed did not become a sufficiently low speed and was close to medium speed, so the effects of low noise and low fuel consumption had to be halved. In order to obtain a sufficient effect, it was necessary to further reduce the rotation speed during auto idle.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a method and an apparatus capable of ensuring responsiveness, reducing the number of revolutions during auto idling to the maximum, and sufficiently obtaining the effects of low noise and low fuel consumption. The purpose is to do.

[0005]

SUMMARY OF THE INVENTION In a construction machine, a throttle setting switch and a voltage output from the switch are used to determine an actuating amount of an actuator via a controller, and the movement of the actuator is determined. The fuel injection amount is increased / decreased according to the rotation angle of the control lever in conjunction with the control lever attached to the injection pump of the engine, and the set rotation at the time of auto idle is set according to the engine speed set during work. The number was changed automatically so that the rotation speed was low.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the number of revolutions of the conventional auto idle is set to a constant value in consideration of the response until the maximum revolution is reached. However, since the construction machine generally adjusts the engine speed according to the content of the work, the work is not always performed at the maximum speed.

According to the present invention, when the engine is used at a speed lower than the maximum rotation speed, the rotation speed of the auto idle is lowered by about the difference between the rotation speeds (maximum rotation speed-rotation speed used during work). However, the responsiveness does not deteriorate. In other words, depending on the engine speed set at the time of work, the rotation at the time of auto idle is made as slow as possible within the range where the responsiveness is not deteriorated, and the effect of low noise and low fuel consumption is maximized.

Here, a calculation formula is derived for the response time (injection time) of the engine speed. There difference △ T between the maximum torque T ₁ of the at rotational speed N ₁ and the load torque Tp ₁ represents a margin torque at the rotational speed, if △ T was used to accelerate the噴上Rinotame at this time, the following The formula of is established.

[0009]

[Equation 1]

From the equation (6), the response time (injection time) of the engine is proportional to the change in the rotational speed due to the injection and inversely proportional to the margin torque.

Now, point A shown in the engine speed-torque characteristic diagram of FIG. 2 is when the work is stopped, and the load torque Tp ₀ is a torque (drag torque) necessary for maintaining the rotation. Point A ₁ is when the work starts and a load torque is applied during the work. Point A ₂ indicates the end of the uplift.

The throttle set amount-engine speed characteristic diagram of FIG. 3 is a conventional example and shows the relationship between the engine speed at the time of work and at the time of auto idle. Engine Nmax rpm
When (Na) is determined, Nb is determined in consideration of the jetting time Tab from the rotation speed Nb to Na within a range that does not hinder the work. Then, even if Nc and Ne are set when the throttle setting amount is reduced and the rotational speed during work is lowered below Na,
The rotation speed at idle was constant at N ₁ = Nb.

On the other hand, FIG. 4 shows an example of the present invention. When the engine speed Nmax (Na) is determined, Tab is taken into consideration to determine Nb. In c and d ', N is set as the uplift time up to Nc
Set d ′. For e and f ', the eruption time to Ne is Ta
When set to b, the rotation speed will be lower than the minimum rotation speed Min during normal work, so the lower limit value is suppressed at Nmin. The effect is apparent from the difference in the rotational speed N ₁ at the time of auto idling in FIGS. 3 and 4, and the effects of low fuel consumption and low noise when work is stopped are large (see the shaded area in FIG. 5).

When the present invention is applied to the device (see FIG. 1), it is as follows. With the voltage output from the throttle setting switch 1, the actuator 3 via the controller 2
Determine the working amount of. The actuator 3 and the control lever 5 attached to the injection pump of the engine 4 are connected so as to interlock with each other. The fuel injection amount increases or decreases depending on the rotation angle of the control lever 5. The engine speed increases with increasing fuel, and decreases with decreasing fuel.

In order to set the engine speed during work with such a device, when the throttle setting switch 1 is adjusted, the controller 2 issues a command to the actuator 3 to require the controller lever 5. Rotate to position. This gives the engine speed during work. Then, the controller 2 calculates and stores the rotational speed at the time of auto idling at the position of the throttle setting switch 1. As a result, when the signal to stop the work is input to the controller 2, the actuator 3 is operated and the control lever 5 is rotated to set the target auto idle speed.

[0016]

[Effect] The operation amount of the actuator 3 is determined by the voltage output from the throttle setting switch 1 via the controller 2, and the movement of the actuator 3 is controlled by the control lever 5 attached to the injection pump of the engine 4. The fuel injection amount is increased / decreased according to the rotation angle of the control lever 5 in association with the engine speed corresponding to the engine speed set during the work, and the set speed during auto idle is automatically changed. I tried to rotate at low speed. As a result, the number of revolutions during auto idling was reduced to the maximum, and low noise and fuel-efficient driving became possible.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus for carrying out the method of the present invention.

FIG. 2 is an engine speed-torque characteristic diagram.

FIG. 3 is a throttle set amount-engine speed characteristic diagram showing a relationship between a conventional engine speed and an engine speed during auto idle.

FIG. 4 is a throttle setting amount-engine speed characteristic diagram of the present invention.

FIG. 5 is a diagram showing a difference in fuel consumption between the present invention and a conventional type.

[Explanation of symbols]

1 Throttle setting switch 2 controller 3 Actuator 4 engine 5 Control lever

Claims (2)

[Claims] 1. In a construction machine, a set rotational speed at the time of auto idling is automatically changed corresponding to an engine rotational speed set at the time of work so that a low speed rotation is achieved. Control method for engine speed in construction machinery. 2. The throttle setting switch (1) and the voltage output from the switch (1) are used to determine the actuation amount of the actuator (3) via the controller (2), and the actuator (3) is determined. The fuel injection amount is increased or decreased according to the rotation angle of the control lever (5) by interlocking the movement of (3) with the control lever (5) attached to the injection pump of the engine (4). An apparatus for performing a method of controlling an engine speed in a construction machine.