JPH041434A - Engine control device - Google Patents

Abstract

PURPOSE:To efficiently use engine torque while automatically controlling an engine and surely avoiding engine stalling by controlling a drive object in the direction in which the actual number of revolutions in neared to the target number of revolutions. CONSTITUTION:A controller 11 has a memory part 12 and an operation part 13, and converts an electric control signal, outputted from the operation part 13, into an oil pressure signal with an electromagnetic proportional pressure reducing valve 10 to send the oil pressure signal to a regulator 9 as an inclination rotation angle command signal. Plural governor lever positions (h), (i), (j), (k)..., the numbers of revolutions AhO, AiO, AjO, and AkO of the no load of engines corresponding to the individual governor lever positions, the numbers of revolutions Ahs, Ais, Ajs, Aks... of control starting, and the target number of revolutions Ajt are previously set in the memory part 12 to be memorized. Moreover a governor lever position signal from a detector 14, detecting the position of the governor lever 5, and an actual number of revolutions signal from a detector 15, detecting the actual number of revolutions of the engine 1, are inputted in the operation part 13. In the operation part 13, to near the actual number of revolutions Ai to the target number of revolutions Ajt, PID control according to the difference DELTAAi between them is conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an engine that simultaneously drives a plurality of objects such as a hydraulic pump and a torque converter, such as a crane engine.

[Conventional technology]

The conventional technology will be explained using a crane as an example.

In FIG. 3, reference numeral 1 denotes an engine, and power from the engine 1 is applied via a power divider 2 to a torque converter 3 and a hydraulic pump 4, which are objects to be driven. 5 is a governor lever that sets the no-load rotation speed of the engine 1.

The torque converter 3 is provided with a modulating clutch that can freely change the coupling degree (power transmission degree) based on a signal from the modulating clutch controller 7 based on the rotational operation of the grip 6. A hoisting winch (not shown) is rotationally driven.

On the other hand, the tilting angle of the hydraulic pump 4 that drives a hydraulic actuator such as a swing motor is commanded by a signal from a regulator 9 operated by a lever 8, thereby controlling the pump discharge flow rate (pump horsepower).

In such a lane drive system, for economic reasons, the engine capacity is set to such a value that one of the torque converter 3 and hydraulic pump 4 can be operated at its rated value independently, but it is not possible to operate both at the same time. is customary.

Therefore, when both are operated at the same time, there is a possibility that the total load torque exceeds the rated torque of the engine 1.

This will be explained with reference to the torque-revolutions characteristic of the engine shown in FIG.

In the figure, the curve ■ is the engine torque curve, and the curve ■ is the torque converter torque curve (the broken line shows the torque curve when the degree of engagement of the modulating clutch is changed). The portion obtained by subtracting the torque converter load torque from the engine torque becomes the load torque (pump load torque) distributed to the hydraulic pump 4.

In addition, in the figure, the straight line ■ indicates the change state of the engine rotation speed and torque with respect to the increase in load, such as the no-load rotation speed Aid (rpm 1 or less).

When a load is applied from a no-load state, the engine speed and torque change on a straight line ■, and the engine rated torque at that time (varies depending on the no-load speed) is reached at the speed A.

Then, with this point (indicated by a black dot) as an inflection point, the rotation speed and torque change along the engine torque curve I as the load increases, and the load state exceeds the rotation speed Aj+ of the engine peak torque TEP. Then the engine stalls.

On the other hand, when the no-load rotational speed is below AjO, the engine rated torque is reached at the rotational speed Aj+ or below, as shown by the straight line (■), and as soon as the load increases thereafter, the engine stalls.

[Problem to be solved by the invention]

Conventionally, when there is a risk that the sum of the torque converter load and the hydraulic pump load exceeds the engine rated torque at that time, the driver senses this from the engine sound and moves the lever 8 or grip 6 in the load reducing direction. I try to operate it accordingly. In this case, when you do not want to reduce the engine speed too much (for example, when you want to maintain high-speed operation of the actuator), set the rotation speed A11 as the target value, and when you want to increase the total load torque even if the engine speed is lowered (for example, when you want to increase the total load torque) (During heavy load work), the rotational speed Aj+ at which the engine peak torque TEP is obtained is set as the target value.

However, such operations are performed mainly based on the driver's intuition and experience, relying mainly on the engine sound, which puts a heavy burden on the driver and can easily cause errors, causing the engine to stall, or discrepancies between the target rotation speed and the actual rotation speed. There was a problem that the difference between the two was large and the engine torque could not be used efficiently.

SUMMARY OF THE INVENTION Accordingly, the present invention provides an engine control device that can automatically and accurately perform engine control to efficiently use engine torque while avoiding engine stalling.

[Means to solve the problem]

The present invention provides a controller for controlling the operation of a driven object such as a hydraulic pump driven by an engine, a set no-load rotation speed detection means for detecting the no-load rotation speed of the engine set by a governor lever, and an actual engine rotation speed. and an actual rotation speed detection means for detecting the rotation speed of the controller, the controller includes a storage section and an arithmetic section, and the storage section stores a plurality of no-load rotation speeds and a number of rotation speeds set in advance corresponding to the no-load rotation speeds. The control start rotation speed and the target rotation speed are stored as control data, and the calculation section calculates the control start rotation speed at that time from the set no-load rotation speed detected by the set no-load rotation speed detection means and the control data. and the target rotation speed,
When the actual rotational speed detected by the actual rotational speed detecting means reaches the control start rotational speed, the driven object is controlled in a direction to bring the actual rotational speed closer to the target rotational speed.

[Effect]

With this configuration, the engine is automatically controlled in a direction in which the engine rotational speed approaches the target rotational speed through control of the driven object. Therefore, engine torque can be used efficiently while engine stalling is reliably avoided.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, only the differences from the prior art shown in FIG. 3 will be explained. In addition to being controlled by manual operation of a lever 8 as before, the regulator 9 that commands the tilting angle of the hydraulic pump 4 is also controlled by the electromagnetic proportional pressure reduction. It is also controlled by a pump controller 11 via a valve 10.

That is, the controller 11 includes the storage section 12 and the calculation section 1.
3, and the electrical control signal output from the calculation unit 13 is converted into a hydraulic signal by the electromagnetic proportional pressure reducing valve 10 and sent to the regulator 9 as a tilting angle command signal.

As shown in FIG. 2, the storage unit 12 of the controller 11 stores a plurality of governor lever positions 1j, k, . . . and engine no-load rotational speeds AhO3Aid, Aid, AkOl corresponding to each governor lever position. and control start rotation speed, Aki, A mouth, Aji, Ak
i... and the target rotation speed are set and stored in advance.

In this case, if the governor lever is at a position where the no-load rotational speed is equal to or higher than AjO (the no-load rotational speed at which the engine peak torque TEP becomes the engine rated torque), i, j... are all rotational speeds at the engine peak torque TEP. At the governor lever position k where Ai+ is set as the target rotation speed and the no-load rotation speed is less than AjO, the rotation speed Ak at the engine rated torque corresponding to each governor lever position
i... is set as the target rotation speed.

That is, at each governor lever position, the rotation speed at which the maximum engine torque is exerted is set as the target rotation speed.

In addition, the control start rotation speed Abt, Aid, Aid,
Aki... is the rotational speed Ahl at the engine rated torque at each governor lever position. Alt, , Ait
, Aki..., that is, a rotation speed at which there is a risk of engine stalling if left as is.

On the other hand, the calculation unit 13 receives a governor lever position signal from a governor lever position detector 14 such as a potentiometer that detects the position of the governor lever 5, and a rotation speed detector 15 that detects the actual rotation speed of the engine 1 during operation. The actual rotational speed signal is input.

The calculation unit 13 performs the following calculations and pump control based on previously stored control data and these input signals.

For example, when the governor lever position signal corresponds to governor lever position 1, the no-load rotation speed AiO corresponding to this governor lever position is selected from the control data in the storage unit 12.
Read out the control start rotation speed AIS and the target rotation speed Aj+. On the other hand, if the governor lever position signal does not correspond to the stored governor lever position, the control start rotation speed and target rotation speed are determined by interpolation based on data values close to the stored governor lever position.

For example, if the no-load rotation speed, control start rotation speed, and target rotation speed are A11l, Aid, and Ajt, respectively,
The difference ΔAi (A-A i
Find +).

As a result, when ΔA1≧0, it is assumed that there is no risk of engine stalling and no control is performed.

Then, control is started when ΔAi<Q (when the actual rotation speed becomes less than the control start rotation speed), and in order to bring the actual rotation speed A1 closer to the target rotation speed Ajr, ΔA1
Performs PID control according to the

That is, the excitation current of the electromagnetic proportional pressure reducing valve 10 is determined by PID calculation, and the hydraulic pump 4 is controlled via the regulator 9 by outputting this.

Through this control, the engine rotation speed Ai is set to the target rotation speed Aj.
It can be brought close to 1. However, since there are a wide variety of combinations of torque converter load and pump load at the start of control, this control alone will not bring the engine speed Ai to the target rotation speed A! may not be equal to

Therefore, after a certain period of time has elapsed, the calculation unit 13 calculates the deviation ΔA between the engine rotation speed A1' and the target rotation speed A't at that time.
By calculating i'(Ai'-Ait) and performing PID control similar to the above again, the engine rotation speed Ai
' to the target rotation speed Ajl as much as possible.

In this way, the engine speed can be automatically set to a speed at which the maximum engine torque is achieved at the current governor lever position (no-load speed) while avoiding engine stall.

In addition, in all governor lever positions where the no-load rotational speed is AiO or higher, the rotational speed Aj+ at engine peak torque TEP is set as the target rotational speed, so it is possible to handle the maximum load torque. can.

However, in the case of a governor lever position where the no-load rotational speed is AiO or more, the rotational speed at the engine rated torque at each governor lever position is set to the target rotational speed, as in the case of a governor lever position where the no-load rotational speed is less than AiG. You can also set it as . Even in this case, the intended purpose of efficiently using engine torque while avoiding engine stalling can be fully achieved.

Furthermore, in the above embodiment, the object to be driven by the engine is a combination of the torque converter 3 and the hydraulic pump 4, and the engine 1 is controlled through the hydraulic pump 4, but the structure is such that the engine is controlled by controlling the torque converter 3. You can also take On the other hand, the present invention can also be applied to combinations of driven objects such as a combination of a plurality of hydraulic pumps, a combination of a plurality of torque converters, or a combination of a plurality of torque converters and hydraulic pumps. Furthermore, a plurality of drive objects may be controlled with priority (for example, the first object and the second object at a ratio of 12).

〔Effect of the invention〕

As described above, according to the present invention, a plurality of no-load rotational speeds and a plurality of corresponding no-load rotational speeds are set in advance in the memory section of a controller that controls the operation of a driven object such as a hydraulic pump driven by an engine. The control start rotation speed and the target rotation speed are stored as control data, and the calculation unit of the controller starts the control at that time based on the set no-load rotation speed detected by the set no-load rotation speed detection means and the control data. The rotational speed and the target rotational speed are determined, and when the actual rotational speed detected by the actual rotational speed detection means reaches the control start rotational speed, the driven object is controlled in a direction that brings the actual rotational speed closer to the target rotational speed. With this configuration, it is possible to efficiently use engine torque while reliably avoiding engine stall.

[Brief explanation of the drawing]

Fig. 1 is a block configuration diagram for explaining the present invention in detail, Fig. 2 is a diagram showing the control data stored in advance using the engine torque curve, and Fig. 3 is a diagram explaining the conventional technology. FIG. 4 is a block diagram showing the torque curve of the engine. 1... Engine, 3... Torque converter as a driven object, 4... Hydraulic pump, 5... Engine governor lever, 9... Hydraulic pump regulator,
10...An electromagnetic proportional pressure reducing valve that controls the regulator,
DESCRIPTION OF SYMBOLS 11... Controller, 12... Storage part of controller, 13... Same calculating part, 14... Governor lever position detector for detecting the governor lever position (no-load rotation speed), 15... Actual engine Engine speed detector to detect rotation speed. Patent applicant: Kobe Seikisho Co., Ltd., agent Patent attorney: Etsushi Kotani, patent attorney
Long 1) Positive amount Patent attorney Takao Ito First prisoner engine rotation number (rl) m) Figure

Claims (1)

[Claims] 1. A controller that controls the operation of a driven object such as a hydraulic pump driven by the engine, a set no-load rotation speed detection means that detects the engine no-load rotation speed set by the governor lever, and a set no-load rotation speed detection means that detects the engine no-load rotation speed set by the governor lever. The controller includes a storage section and a calculation section, and the storage section stores a plurality of no-load rotation speeds and a preset control start rotation speed corresponding thereto. and target rotation speed are stored as control data,
The calculation section calculates the control start rotation speed and target rotation speed at that time from the set no-load rotation speed detected by the set no-load rotation speed detection means and the control data, and calculates the control start rotation speed and target rotation speed at that time from the set no-load rotation speed detected by the set no-load rotation speed detection means, and determines the control start rotation speed and target rotation speed at that time, and An engine control device characterized in that the engine control device is configured to control a driven object in a direction to bring the actual rotation speed closer to the target rotation speed when the detected actual rotation speed reaches the control start rotation speed.