KR20000033808A - Apparatus for controlling engine of construction equipment - Google Patents

Abstract

PURPOSE: A controlling apparatus of an engine of a construction equipment is provided to reduce engine torque and also fuel efficiency by using a small engine proper for the capacity of multiple pumps and by preventing the stall of an engine by returning the force of a portion of pumps to a tank after starting an engine. CONSTITUTION: A venting pressure of a first pump(43) is vented to a working and traveling device(46) for preventing the stall of an engine at the first stage of starting an engine, but the venting pressure of a second pump(44) is returned and flowed into a tank(42) without being vented to the working and traveling device. Then an engine(41) for optimal use is not stalled at the first stage of starting. Herein, a tank returning unit(49) is installed to the second pump for the returning of operation oil of the second pump, and control signals of a controller(48) is received. The controller compares the rotational frequency measured by a rotation frequency detecting unit(47) with a predetermined reference rotational frequency. If the measured rotational frequency is lower than the reference one, a pump returning signal is output. So the tank returning device is opened, and the operation oil is returned to the tank. Thereby, excessive torque is not formed in the engine. If the measured rotational frequency is lower than the reference rotational frequency, a pump returning signal is output.

Description

Engine control device of construction equipment

The present invention relates to an engine control apparatus for construction equipment.

More particularly, the present invention relates to an engine control apparatus for construction equipment that reduces torque applied to an engine when the engine rotates at a low speed, thereby preventing stall of the engine and reducing fuel economy.

In general, a work machine such as a construction machine uses an engine to obtain a force for moving the vehicle forward or backward or an actuator, and the rotation speed of the engine is controlled by the driver's accelerator pedal or the position of the shift lever. Will be.

1 is a schematic block diagram of an engine and a pump of a conventional construction equipment.

As shown in the drawing, a high-power engine 11 for outputting high torque, a tank 12 for storing hydraulic oil, and a first oil for discharging hydraulic oil stored in the tank 12 according to the output of the high-power engine 11. To the pump 13 and the second pump 14, the check valve 15 for preventing the discharge pressure in the reverse direction of the second pump 14, and the first pump 13 and the second pump 14. And a traveling device 16 for carrying out the forward, reverse or work of the vehicle according to the hydraulic fluid discharged by the vehicle.

2 is a view showing a torque curve of a conventional high power engine.

As shown, the N-axis represents the engine speed and the T-axis represents the torque of the engine.

That is, T1 represents the maximum torque value that can be used when only the first pump 13 is operated, and T2 represents the maximum torque value that can be used when the first pump 13 and the second pump 14 are used together. N1 represents the minimum rotational speed of the starting state of the high power engine 11, N1-Nn is a working period in which the high power engine 11 can work, and Nn represents the high power engine 11. Indicates the maximum number of revolutions that can be made.

In addition, the S-curve, which is a high output torque curve, is a torque value for each engine speed at which the high-power engine 11 can exert a force under a full load condition.

Therefore, since the torque value of the S-curve is higher than T2 at the point N1 which is the minimum rotational speed of the high-power engine 11, when the engine is started, the engine is not stalled and the engine is operated. The torque produced by the engine depends on the engine speed of the engine, and the output of the engine is 'engine speed × torque', so the output increases as the engine speed increases.

However, as shown in FIG. 2, in the work section of N1-Nn, the engine has more torque S or output than the torque T2 or output required when the engine is working in earnest. That is, the maximum amount of work that can be performed even when operating the first pump 13 and the second pump 14 is the maximum T2, but the performance torque of the high-power engine 11 has an S curve, so As the torque was used, the high-power engine 11 used fuel inefficiently.

Therefore, conventionally, since a high-power engine is used, not only the manufacturing cost of the engine is high but also fuel consumption is problematic.

Therefore, an object of the present invention is to reduce the engine torque by using a small engine suitable for the capacity of a plurality of pumps and in the initial state after the engine start to return the power of some pumps to the tank using a controller to prevent engine stall. The purpose is to provide engine control of construction equipment to reduce fuel consumption.

1 is a block diagram of an engine control apparatus of a conventional construction equipment,

2 is a view showing a torque curve of a conventional high power engine,

3 is a block diagram of an engine control apparatus for construction equipment of the present invention;

Figure 4 is a block diagram of an embodiment in which two pumps are mounted on the engine control apparatus of the construction equipment of the present invention,

5 is a diagram showing a torque curve of an optimum engine according to the embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

31: optimum engine 32: tank

33: a plurality of pump means 34: work and travel device

35: rotation speed detection means 36: controller

37 tank return means 38 check valve

An engine control apparatus for construction equipment according to the present invention for achieving the above object is to discharge the hydraulic oil stored in the tank according to the output of the optimum engine, the tank for storing the hydraulic fluid, and the optimum engine for the optimum torque A plurality of pump means, a check valve for preventing discharge pressure in the reverse direction of the plurality of pump means, a work and traveling device for performing forward, backward or work of the vehicle according to the hydraulic oil discharged by the plurality of pump means, The rotation speed detection means for detecting the engine speed of the applied engine and the measured rotation speed measured from the rotation speed detection means are compared with the preset reference rotation speed. A controller for outputting a signal and a plurality of pumps for receiving a pump feedback signal output from the controller and for returning the hydraulic oil discharged to a predetermined pump to a tank. It consists of a tank return means.

Hereinafter, with reference to the accompanying drawings illustrating a configuration and an embodiment of the engine control apparatus of the construction equipment of the present invention.

3 is a block diagram of an engine control apparatus for construction equipment of the present invention.

As shown, a plurality of pumps for discharging the hydraulic oil stored in the tank 32 according to the output of the optimum engine 31, the tank 32 for storing the hydraulic oil, and the optimum engine 31 for the optimal torque Depending on the pump means 33, the check valve 38 for preventing the discharge pressure in the reverse direction of the plurality of pump means 44, and the hydraulic oil discharged by the plurality of pump means 33, In accordance with the work to be performed and the traveling device 34, the rotation speed detection means 35 for detecting the engine speed of the optimum engine 31, and the measured rotation speed measured from the rotation speed detection means 35. The controller 36 outputs a plurality of feedback signals, and a plurality of tank feedback means 37 for receiving the feedback signal output from the controller 36 and for returning the hydraulic oil discharged to a predetermined pump to the tank 32. do.

The controller 36 compares the measured rotation speed measured by the rotation speed detecting means 35 with a preset reference rotation speed, and outputs a pump feedback signal when the comparison result is smaller than the reference rotation speed. do.

The reference speed is characterized in that the engine speed at the time when the torque of the optimum engine 31 becomes larger than the total torque of the plurality of pump capacity.

Figure 4 is a block diagram of an embodiment equipped with two pumps of the engine control apparatus of the construction equipment of the present invention.

An optimum engine 41 for producing optimum torque, a tank 42 for storing hydraulic oil, a first pump 43 for discharging hydraulic oil stored in the tank 42 according to the output of the optimum engine 41, and To the hydraulic fluid discharged by the second pump 44, the check valve 45 for preventing the discharge pressure in the reverse direction of the second pump 44, and the first pump 43 and the second pump 44. From the work and the traveling device 46 for performing the forward, reverse or work of the vehicle, the rotation speed detecting means 47 for detecting the engine speed of the optimum engine 41, and the rotation speed detecting means 47. The measured rotation speed is compared with the preset reference speed.If the measurement speed is less than the reference speed, the pump feedback signal is output. If the measurement speed is not less than the reference speed, the feedback signal is not output. Receives the feedback signal output from the controller 48 and the controller 48, and sends it to a predetermined pump. The operating fluid consists of a tank feedback means 49 which feeds back to the tank 42.

5 is a diagram showing a torque curve of an optimum engine according to the embodiment of the present invention.

As shown in Figures 4 and 5, the N-axis represents the engine speed and the T-axis represents the torque of the engine.

That is, T1 represents the maximum torque value that can be used when only the first pump 43 operates, and T2 represents the maximum torque value that can be used when the first pump 43 and the second pump 44 are used together. N1 represents the minimum rotational speed of the starting state of the optimum engine 41, N2-Nn is a working period in which the optimum engine 41 can work, and Nn represents the optimum engine 41. Indicates the maximum number of revolutions that can be made.

In addition, S curve is a torque curve in the full load condition of the conventional high output engine, and S 'curve is a torque curve in the full load condition of the said engine 41 for optimal use of this invention.

That is, the S 'torque curve that is the torque and output performance of the optimum engine 41 is lower than the S torque curve that is the torque and output performance of the conventional high output engine. The engine is lower than the conventional engine.

Therefore, by using an engine with a small output, the manufacturing cost of the engine is reduced, and fuel consumption is small, thereby reducing fuel consumption.

However, when the engine speed of the optimum engine 41 is from the N1 point, which is the lowest rotational speed, which is the initial starting point of the engine, to the N2 point, the torque value of the S 'curve is lower than T2, causing the engine to stall. do.

Therefore, in order to prevent the engine from stalling in the initial state of starting the engine, the discharge pressure of the first pump 43 is discharged to the work and the traveling device 46, but the discharge pressure of the second pump 44 is operated and traveled. If the pump is fed back into the tank 42 without being discharged to the apparatus 46, the optimum engine 41 is not stalled in the initial starting state. That is, the torque of the engine 41 for optimization is higher than the maximum torque value of T1 in the area | regions N1-N2.

Therefore, in order to return the hydraulic oil of the second pump 44, the tank return means 49 is mounted on the second pump 44 to receive the control signal of the controller 48.

The controller 48 compares the measured rotational speed measured by the rotational speed detection means 47 with a preset reference rotational speed, and the reference rotational speed has an adjustment smaller than N2. That is, the reference rotational speed indicates the engine rotational speed at the time when the torque of the optimum engine 41 becomes larger than the total torque of the plurality of pump capacities.

The measured rotational speed is compared with the preset reference rotational speed, and when the measured rotational speed is smaller than the reference rotational speed, the pump feedback signal is output to open the tank feedback device 49, and the hydraulic oil is returned to the tank 42 so as to provide an engine. Do not generate excessive torque on the pump and do not output the pump feedback signal if the measured speed is not less than the standard speed.

When the measured rotation speed is greater than the reference rotation speed, the vehicle is a work section, and the second pump 44 also discharges the discharge pressure, and the worker may perform the work normally.

The engine control apparatus for construction equipment according to the present invention constructed and acting as described above uses an optimum engine suitable for a plurality of pumps, and in the initial state after starting the engine, the power of some pumps is returned to the tank to make the engine stall. By preventing it, it is possible to reduce the engine torque to reduce fuel consumption and reduce the manufacturing cost of the engine.

Claims (2)

An optimum engine for producing optimum torque; A tank for storing hydraulic oil; A plurality of pump means for discharging hydraulic oil stored in the tank according to the output of the optimum engine; A check valve for preventing discharge pressure in a reverse direction of the plurality of pump means; A work and a traveling device for performing forward, backward or work of the vehicle according to the hydraulic oil discharged by the plurality of pump means; Rotation speed detection means for detecting an engine speed of the optimum engine; A controller for comparing the measured rotational speed measured by the rotational speed detection means with a preset reference rotational speed and outputting a plurality of pump feedback signals when the comparison result is smaller than the reference rotational speed; And a plurality of tank feedback means for receiving the pump feedback signal output from the controller and returning the hydraulic oil discharged to the predetermined pump to the tank. The method of claim 1, wherein the reference speed is; The engine control apparatus of the construction equipment characterized by indicating the engine speed at the time when the torque of the said optimum engine becomes larger than the total torque of several pump capacity.