JP4743512B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control apparatus that controls an engine droop amount.

  A cooling fan is directly connected to an engine mounted on a construction machine, and a direct acting fan that obtains a passing air amount necessary for a cooling device such as a radiator and an oil cooler by this cooling fan is generally used (for example, a patent) Reference 1).

  With such a direct-acting fan, the engine speed (hereinafter referred to as engine speed) and fan speed (hereinafter referred to as fan speed) are equal, so noise and cooling capacity are in a contradictory relationship. It has been known.

  That is, noise can be reduced by reducing the opening of the enclosure and reducing the fan rotation speed of the cooling fan. On the other hand, the cooling device can be increased by increasing the opening of the enclosure and increasing the fan rotation speed. The passage air volume increases and the cooling capacity increases.

  However, the cooling capability requires a high capability when the calorific value (engine load) of the machine is high, and a low capability is sufficient when the calorific value is low.

  Here, the characteristics of the engine mounted on a general construction machine are shown by a solid line in FIG. 8 showing the relationship between the engine speed and the engine power.

  As shown in the use region in the solid line characteristic diagram of FIG. 8, the engine speed is generally lower as the engine load is higher, that is, as the engine power is required.

  In the case of a direct-acting cooling fan directly connected to the engine, the engine speed and the fan speed are in a directly proportional relationship.

  This means that the fan speed increases when the engine load is light, and unnecessary noise is generated in a region where the cooling capacity of the cooling fan may be low.

  From this, it can be seen that noise can be reduced by reducing the air volume at light load and no load when cooling capacity is not required.

  On the other hand, control of fan rotation speed is possible when the fan rotation speed is controlled by an electric motor drive fan or a hydraulic motor drive fan (for example, refer to Patent Document 2) in which the cooling fan does not move directly with the engine, or a clutch. If the system is possible, it is easy to obtain the fan speed according to the situation.

  However, when it is mounted on a construction machine, it cannot be said that such a cooling fan capable of controlling the rotation speed can be mounted on any construction machine in terms of space and cost.

  Therefore, attention is paid to the following characteristics of an engine that is electronically controlled by an electronic governor, which is becoming common in construction machines, in response to recent exhaust gas regulations.

  In an engine that is electronically controlled by this electronic governor, it is possible to relatively freely set the droop curve parameter, that is, the droop amount, as shown by the solid line, dotted line, and alternate long and short dash line in FIG.

  By setting the droop amount to a small value, it is possible to reduce the engine speed when there is no load. For example, as shown in FIG. 8, the droop amount is changed from type 1 to type 2 and further to type 3 By making the change to a small value, it is possible to reduce the engine speed at light load and at no load, thereby suppressing the fan speed.

Further, by suppressing the fan rotation speed during light load and no load, the generation of fan noise can be reduced, and reduction in ambient noise of the work machine can be expected.
JP 2002-47965 A (first page, FIG. 1) JP 2003-139107 A (first page, FIG. 1)

  On the other hand, by setting the droop amount to be small, the following disadvantages also occur.

A: In actual work, the load is constantly fluctuating. Therefore, when considered in total, the total air volume with respect to the total load is lowered, and the cooling capacity is lowered.

B: When there is a sudden load application, the engine speed at the time of no load is close to the rated speed, so that an engine drop in which the engine speed drops rapidly is likely to occur.

  As described above, the direct-acting fan generates unnecessary noise in an area where the cooling capacity may be low, and the motor-driven fan capable of controlling the fan rotation speed is limited in installation space and cost. In addition, there is a problem, and if the droop amount of the engine controlled by the electronic governor is simply set small, there is a problem that the cooling ability is lowered and the engine is dropped.

  The present invention has been made in view of the above points, and is intended to reduce the number of fan revolutions in an engine having an inexpensive direct acting cooling fan without adding or improving a special cooling system. An object of the present invention is to provide an engine control device capable of reducing noise generated from a cooling fan.

The invention according to claim 1 has an electronic governor, and the electronic governor allows the droop amount to be controlled in a region between the rated engine speed of the engine characteristics and the engine speed at no load higher than the rated engine speed. Controlled engine, direct acting cooling fan directly connected to the engine, a cooling unit for cooling the cooled fluid by the cooling fan, a temperature sensor for detecting the temperature of the cooled fluid, and the temperature sensor The engine control device includes a droop amount controller that controls the droop amount of the engine to be increased in accordance with the temperature rise of the fluid to be cooled detected by the above.

The invention according to claim 2 has an electronic governor, and the electronic governor is an electronic device capable of controlling the droop amount in a region between the rated engine speed of the engine characteristics and the engine speed at no load higher than the rated engine speed. A control engine, a direct-acting cooling fan directly connected to the engine, a cooling unit that cools a fluid to be cooled by the cooling fan, and a droop amount controller that variably controls the engine droop amount. The droop amount controller determines the work pattern from the past work situation, and in the work pattern where there is a high possibility of sudden load application, the engine droop amount is set large, and there is a high possibility that there is no sudden load application. In the work pattern, the engine control device sets the engine droop amount small.

According to a third aspect of the present invention, there is provided an electronic governor which has an electronic governor and is capable of controlling a droop amount in a region between a rated rotational speed of engine characteristics and an engine rotational speed when no load is higher than the rated rotational speed. A control engine, a direct-acting cooling fan directly connected to the engine, a cooling unit that cools a fluid to be cooled by the cooling fan, and a droop amount of the engine according to a mode selected from a plurality of modes An engine control device includes a droop amount controller that performs variable control, and mode selection means that instructs the droop amount controller to select a mode.

  According to the first aspect of the present invention, the droop amount controller controls the droop amount of the electronically controlled engine in accordance with the temperature rise of the cooled fluid detected by the temperature sensor, Even when the load is light or no load, it is possible to prevent a decrease in the engine speed, that is, the fan speed, so that the air volume necessary for cooling the cooling unit can be secured to prevent a decrease in the cooling capacity and the temperature of the fluid to be cooled. Before the engine speed rises, by controlling the droop amount to be small, the engine speed at the time of light load or no load, that is, the fan speed can be suppressed low, so that the noise generated from the cooling fan can be reduced.

  According to the second aspect of the present invention, in a work pattern in which there is a high possibility that a sudden load is applied, an engine drop when the sudden load is actually applied by setting a large droop amount of the electronically controlled engine. In a work pattern where there is a high possibility that there will be no sudden load input, setting the droop amount to a small value can reduce the engine speed at the time of light load or no load, that is, the fan speed. Noise generated from the can be reduced.

  According to the third aspect of the invention, for example, by selecting a mode under extreme heat conditions and setting a large droop amount, the engine speed, that is, the fan speed is reduced even at light load or no load. Therefore, it is possible to secure the fan air volume necessary for cooling the cooling unit to prevent the cooling capacity from being lowered.For example, select the mode under the condition where low noise is required, and set the droop amount small. By doing so, the engine speed at the time of light load and no load, that is, the fan speed can be suppressed low, so that the noise generated from the cooling fan can be reduced.

  Hereinafter, the present invention is shown in the first embodiment shown in FIGS. 1 to 4, the second embodiment shown in FIG. 5, the third embodiment shown in FIG. 6, and the FIG. This will be described in detail with reference to the fourth embodiment. 1 to 3 are a block diagram and a characteristic diagram that are common to the embodiments shown in FIGS.

  First, the first embodiment shown in FIGS. 1 to 4 will be described.

  FIG. 1 shows an outline of an engine control device mounted on a work machine such as a hydraulic excavator. A direct-acting cooling fan 13 is directly connected to an engine 12 having an electronic governor 11 and electronically controllable by the electronic governor 11. A cooling unit 14 that cools the fluid to be cooled by the cooling fan 13 is disposed in the vicinity.

  The cooling unit 14 supplies hydraulic fluid as a cooled fluid supplied to a hydraulic circuit 15 such as a radiator that cools engine cooling water as a cooled fluid, a hydraulic cylinder that operates a working device of a work machine, and a hydraulic motor. A heat exchanger core such as an oil cooler for cooling is assembled.

  The electronic governor 11 controls the engine speed by controlling an electronic fuel injection device (injector) 16 with an engine controller 17, and the engine controller 17 controls the entire body including the hydraulic circuit 15 and the like. Connected to controller 18.

  The body controller 18 and the engine controller 17 are connected to rotation speed sensors 19A and 19B for detecting the engine rotation speed, respectively. The engine controller 17 is connected to a cooling water temperature sensor 20 as a temperature sensor for detecting the cooling water temperature of the engine cooling water. Is connected.

  A hydraulic oil temperature sensor 22 as a temperature sensor for detecting the temperature of the hydraulic oil is provided in the hydraulic oil tank 21 that contains the hydraulic oil of the hydraulic circuit 15, and the hydraulic oil temperature sensor 22 is provided by an operator of the work machine. It is connected to the body controller 18 and the engine controller 17 via a monitor 23 as mode selection means installed at a position where it can be operated and monitored.

The engine 12 electronically controlled by the electronic governor 11 has a droop curve in a region between a rated engine speed of engine characteristics and an engine speed at no load higher than the rated engine speed, and a droop curve parameter (or “droop amount”). The body controller 18 and the engine controller 17 are a droop amount controller 24 that variably controls the droop amount of the engine 12.

  The droop amount controller 24 has a function of controlling the droop amount of the engine 12 to increase in accordance with the temperature rise of the coolant temperature and the hydraulic oil temperature detected by the coolant temperature sensor 20 and the hydraulic oil temperature sensor 22.

  In addition, the droop amount controller 24 determines a work pattern from a work situation for a certain past time based on the engine speed data detected by the speed sensors 19A and 19B, and there is a high possibility that a sudden load is applied. The work pattern also has a function of setting a large amount of droop of the engine 12 and setting a small amount of droop of the engine 12 in a work pattern that is highly likely not to be subjected to a sudden load.

  Further, the monitor 23 functions as a mode selection means for instructing the droop amount controller 24 to select a mode. The droop amount controller 24 is operated according to the mode selected from a plurality of modes by the monitor 23 It has a function to variably control 12 droop amounts.

  As shown in FIG. 2, the engine 12 that is electronically controlled by the electronic governor 11 allows the droop amount to be controlled relatively freely by changing the slope of the droop curve as indicated by the solid line, the dotted line, and the alternate long and short dash line. It is possible to set. Note that the portion exemplified by the straight line of the droop curve may be a curved line or a broken line.

  By setting this droop amount as small as shown by the alternate long and short dash line, the engine speed at the time of light load or near no load when the engine power is near 0 is made lower than when setting it as large as shown by the solid line. For example, as shown in FIG. 2, by changing the droop amount from type 1 to type 2 and further to type 3, the engine speed at light load and no load can be reduced. It is possible to lower. Thereby, the fan rotation speed of the cooling fan 13 directly connected to the engine 12 can be suppressed.

  The droop amount controller 24 can change the droop amount stepwise in accordance with the cooling water temperature, the hydraulic oil temperature or the work pattern as shown by a dotted line in FIG. 3, but is shown by a solid line in FIG. Thus, it can be changed steplessly according to the cooling water temperature or the hydraulic oil temperature.

  Next, the droop amount controller 24 controls the droop amount as follows in order to overcome the decrease in the cooling capacity and the occurrence of engine drop due to the sudden load application.

  First, the cooling state determination function which is the first embodiment of the control by the droop amount controller 24 will be described with reference to FIG.

(Step S1)
If the droop curve parameter (droop amount) has been updated, the updated value is taken into the droop amount controller 24.

(Step S2)
The coolant temperature and the hydraulic oil temperature are detected by the coolant temperature sensor 20 and the hydraulic oil temperature sensor 22, and are taken into the droop amount controller 24.

(Step S3)
The droop amount controller 24 calculates so as to increase the droop amount as the temperature rises in accordance with the detected coolant temperature and hydraulic oil temperature. As shown in FIG. 2 or FIG. One of the plurality of droop curve parameters set in advance is determined. As the cooling water temperature and hydraulic oil temperature change, the droop curve parameters are updated and determined repeatedly.

(Step S4)
Based on the droop amount determined in step S3, the engine controller 17 changes the setting of the electronic governor 11 and changes the droop curve. For example, the droop amount is changed stepwise or steplessly as shown in FIG. 3 according to the increase in the hydraulic oil temperature of the hydraulic circuit 15 and the coolant temperature of the engine 12, as shown by the solid line in FIG. The droop amount is changed in the direction of increasing (from type 3 to type 1 in FIG. 2).

  According to this cooling status determination function, in the situation where the coolant temperature and the hydraulic fluid temperature detected by the coolant temperature sensor 20 and the hydraulic fluid temperature sensor 22 have increased, the droop amount controller 24 controls the droop of the electronically controlled engine 12. By controlling in the direction of increasing the amount, it is possible to prevent a decrease in the engine speed, that is, the fan speed, even at light load or no load, so the air flow necessary for cooling the cooling unit 14 is secured and the cooling capacity Can be prevented, and before the cooling water temperature and hydraulic oil temperature rise, the engine speed at the time of light load or no load, that is, the fan speed, can be reduced by controlling the droop amount to be small. Noise generated from the fan 13 can be reduced.

  Next, a work pattern determination function which is a second embodiment of the control by the droop amount controller 24 will be described with reference to FIG. The outline of the engine control apparatus shown in FIG. 1, the engine characteristics shown in FIG. 2, and the droop amount change characteristics shown in FIG. 3 are the premise of the second embodiment. Is omitted.

(Step S5)
If the droop curve parameter (droop amount) has been updated, the updated value is taken into the droop amount controller 24.

(Step S6)
The engine speed detected by each speed sensor 19A, 19B is taken into the droop amount controller 24.

(Step S7)
The droop amount controller 24 predicts the engine load from the updated droop curve parameter and the detected engine speed.

(Step S8)
The droop amount controller 24 determines the work pattern from the work situation of a past fixed time in order to avoid engine drop at the time of sudden load. The work pattern can be determined by processing engine load time-series data based on the engine speed. For example, the work pattern is calculated as a work pattern parameter from the minimum speed and the average speed for a predetermined past time.

(Step S9)
The droop amount controller 24 changes the droop curve parameter (droop amount) stepwise or steplessly according to the determined work pattern parameter. For example, a droop amount is determined to be large for a work pattern that is likely to have a sudden load input (type 1 in FIG. 2), and a droop amount is determined to be small for a work pattern that is likely not to have a sudden load input (FIG. 2). 2 type 3).

(Step S10)
The engine controller 17 changes the setting of the electronic governor 11 according to the determined droop amount, and changes the droop curve stepwise or steplessly.

  According to this work pattern determination function, for work patterns that are likely to have a sudden load application, the engine drop when the sudden load is actually applied can be set by setting the droop amount of the electronically controlled engine 12 large. In a work pattern where there is a high possibility that there will be no sudden load input, setting the droop amount to a small value can reduce the engine speed at the time of light load or no load, that is, the fan speed. Noise generated from 13 can be reduced.

  Next, a manual mode selection function which is a third embodiment of the control by the droop amount controller 24 will be described based on FIG. The outline of the engine control device shown in FIG. 1, the engine characteristics shown in FIG. 2, and the droop amount change characteristics shown in FIG. 3 are the premise of the third embodiment. Is omitted.

(Step S11)
The monitor 23 provided on the work machine has a function for displaying a plurality of modes and a switch capable of selecting a desired mode from the plurality of displayed modes. The mode forcibly selected in is input to the droop amount controller 24.

(Step S12)
The droop amount controller 24 determines a droop curve parameter (droop amount) corresponding to the mode selected by the monitor 23. For example, when the low noise mode is selected, the droop amount is set to the minimum value (for example, type 3 in FIG. 2), and when the intense heat mode is selected, the droop amount is set to the maximum value (for example, type 1 in FIG. 2). When the mode is selected, the droop amount is set to a standard value (for example, type 2 in FIG. 2).

(Step S13)
Depending on the determined droop amount, the engine controller 17 changes the setting of the electronic governor 11 to change the droop curve stepwise or steplessly. For example, the droop amount is changed to type 1 in FIG. 2 in the severe heat mode, and the droop amount is changed to type 3 in FIG. 2 in the low noise mode.

  According to this manual mode selection function, for example, by selecting a mode under extreme heat conditions and setting a large droop amount, the engine speed, that is, the fan speed can be reduced even at light load or no load. As a result, it is possible to secure the fan air volume necessary for cooling the cooling unit 14 to prevent the cooling capacity from being lowered.For example, select a mode in a situation where low noise is required, and set the droop amount to be small. By doing so, the engine speed at the time of light load and no load, that is, the fan speed can be suppressed low, so that the noise generated from the cooling fan 13 can be reduced.

  Next, an example of a combination as an airframe system which is a fourth embodiment of control by the droop amount controller 24 will be described based on FIG.

  The airframe system includes a cooling state determination function (steps S1 to S3) for setting the droop amount according to the temperature of the fluid to be cooled shown in the first embodiment, and the work pattern shown in the second embodiment. A work pattern determination function (steps S5 to S9) for setting the droop amount according to the mode and a manual mode selection function (steps S11 to S13) for setting the droop amount according to the selected mode shown in the third embodiment. ) Can be operated in combination with each other or independently.

(Step S14)
The body controller 18 determines whether or not the manual mode selection function from the monitor 23 is adopted.

(Step S15)
When the manual mode selection function is employed in step S14, the setting of the engine controller 17 of the electronic governor 11 is changed according to the droop amount manually selected from the monitor 23, and the droop curve is changed.

(Step S16)
If the manual mode selection function from the monitor 23 is not adopted in step S14, the cooling status determination function (steps S1 to S3) and the work pattern determination function (steps S5 to S9) are activated and correspond to each situation. A droop curve parameter (droop amount) is determined. The cooling state determination function and the work pattern determination function can be turned on / off on the monitor 23.

(Step S17)
The droop amounts determined in step S3 of the cooling status determination function and step S9 of the work pattern determination function are not sent to the electronic governor 11, and the respective droop amounts updated in the body controller 18 are updated. Compare each time and use a larger droop amount as the decision value.

(Step S18)
Based on the droop amount determined in step S17, the engine controller 17 changes the setting of the electronic governor 11 and changes the droop curve.

  According to this airframe system, a combination of the functions of the manual mode selection function, the cooling state determination function, and the work pattern determination function makes it possible to obtain a fan speed that is more suitable for the situation.

  In this way, by performing engine control to change the droop curve of the engine 12 according to the hydraulic oil temperature, cooling water temperature or work pattern, etc., an inexpensive direct acting type can be achieved without adding or improving a special cooling system. With the engine 12 having the cooling fan 13, the engine speed can be reduced, and noise generated from the cooling fan 13 can be reduced.

  The engine control device of the present invention can be used not only for a hydraulic excavator but also for other work machines having a cooling unit cooled by a cooling fan directly connected to the engine.

It is a block diagram which shows one Embodiment of the engine control apparatus which concerns on this invention. It is a characteristic view which shows the engine power characteristic of the engine controlled by the control apparatus same as the above. It is a characteristic view which shows the droop amount change characteristic of the engine controlled by the control device same as above. It is a flowchart which shows the cooling condition determination function of a control apparatus same as the above. It is a flowchart which shows the work pattern determination function of a control apparatus same as the above. It is a flowchart which shows the manual mode selection function of a control apparatus same as the above. It is a flowchart which shows the example which combined the control apparatus same as the above with the body system. It is a characteristic view of the engine power characteristic explaining the droop amount change of the engine.

Explanation of symbols

11 Electronic governor
12 engine
13 Cooling fan
14 Cooling unit
20 Cooling water temperature sensor as temperature sensor
22 Hydraulic oil temperature sensor as temperature sensor
23 Monitor as mode selection means
24 Droop amount controller

Claims (3)

An electronically controlled engine that has an electronic governor and can control the droop amount in a region between the rated speed of the engine characteristics and the engine speed at the time of no load higher than the rated speed by the electronic governor;
A direct-acting cooling fan directly connected to this engine,
A cooling unit that cools the fluid to be cooled by the cooling fan;
A temperature sensor for detecting the temperature of the fluid to be cooled;
An engine control device comprising: a droop amount controller that controls the droop amount of the engine to increase in accordance with a temperature rise of the fluid to be cooled detected by the temperature sensor. An electronically controlled engine that has an electronic governor and can control the droop amount in a region between the rated speed of the engine characteristics and the engine speed at the time of no load higher than the rated speed by the electronic governor;
A direct-acting cooling fan directly connected to this engine,
A cooling unit that cools the fluid to be cooled by the cooling fan;
A droop amount controller for variably controlling the engine droop amount;
The droop amount controller
Determine work patterns from past work situations,
For work patterns where there is a high possibility of sudden load input, set the engine droop amount large,
An engine control device characterized in that the engine droop amount is set to be small for work patterns that are likely not to be subjected to sudden loads. An electronically controlled engine that has an electronic governor and can control the droop amount in a region between the rated speed of the engine characteristics and the engine speed at the time of no load higher than the rated speed by the electronic governor;
A direct-acting cooling fan directly connected to this engine,
A cooling unit that cools the fluid to be cooled by the cooling fan;
A droop amount controller that variably controls the engine droop amount according to a mode selected from a plurality of modes;
An engine control device comprising: mode selection means for selecting and instructing a mode to the droop amount controller.

Images