JPH10317964A - Cooling device for engine of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an opening area for ventilation variable by providing a cover opening-closing means driving to open or close an opening-closing cover constituting an engine room, and controlling it so as to open the opening-closing cover when the temperature of engine cooling water exceeds a fixed temperature or there is possibility to exceed it. SOLUTION: The engine room 10 of a construction machine is constituted so that a side wall 11a and an upper opening-closing cover can be opened or closed. In this case, the upper opening-closing cover is utilized for increasing the opening area for ventilation of the engine room, a pinion 31 is provided on the output shaft of a reversible electric motor 30 as the opening-closing mechanism of the upper opening-closing cover, so that the upper opening-closing cover is opened or closed by rotation of the pinion 31 through a rack 32. The electric motor 30 is controlled so as to open the upper opening-closing cover and increase a ventilation quantity when the temperature of engine cooling water rises over a set value, by a control means based on the signals from a cooling water temperature sensor and an atmospheric air temperature sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cooling device for a hydraulic shovel and other construction machines, and more particularly to an engine cooling device that changes a cooling efficiency according to a temperature state of an engine cooling water of a radiator. Things.

[0002]

2. Description of the Related Art In hydraulic excavators and other construction machines, a hydraulic actuator including a hydraulic cylinder and a hydraulic motor is provided. The hydraulic pump is supplied with hydraulic oil to each hydraulic actuator via a directional switching valve to operate the machine. In the constituent parts, for example, in a hydraulic shovel, traveling of the vehicle and turning of the upper revolving unit, and driving of a front working mechanism including a boom, an arm, and a front attachment are performed. An engine is provided for driving the hydraulic pump, and the engine is disposed in the machine room together with the hydraulic pump and other devices. Since high heat is generated from the engine, it is installed in an engine room separated from other devices by an engine cover including a cover and a partition wall. A radiator for supplying cooling water to the engine is also provided in the engine room.

[0003] Here, in the case of construction machines such as hydraulic excavators, work is often performed with the vehicle stopped, and it is necessary to cool the engine during this work.
A cooling fan driven by the engine is configured to forcibly send cooling air to the radiator. For this purpose, a ventilation portion for circulating cooling air is provided on a predetermined wall surface constituting the engine cover. That is, on the wall constituting the engine cover, an inflow-side ventilation portion is provided at a position in front of the radiator, and an exhaust-side ventilation portion is provided at a position on the rear side of the engine. When the outside air taken in from the inflow side ventilation part passes through the radiator, it is cooled by exchanging heat with engine cooling water in the radiator. The air heated by the heat exchange is discharged from the vent on the discharge side.

[0004]

The loud noise is generated because the engine, the cooling fan and the like are provided in the engine room. This noise must be soundproofed so that it does not leak to the outside as much as possible. For this purpose, these devices are placed in the engine cover and soundproofing is applied by attaching soundproofing material to the inner surface of the engine cover.However, since ventilation must be provided on the wall surface, this is required. It is impossible to prevent noise from leaking from the ventilation part to the outside. Since the ventilation part is for flowing cooling air to the radiator, it is necessary to make the opening area as large as possible from the viewpoint of the cooling efficiency of the radiator, and as a result, noise leakage increases. From the above, the shape and opening area of the ventilation section are set so as to satisfy the two requirements of cooling efficiency of the radiator and noise reduction,
It is impossible to increase the opening area without darkness.

Therefore, the opening area of the ventilation section is made variable,
Normally, the opening area of the ventilation part is minimized to reduce noise, and if the engine cooling water in the radiator adversely affects the operation of the engine and the temperature rises to a degree that the engine may overheat A configuration in which the opening area of the ventilation section is increased to improve the cooling efficiency is conventionally known.
As described above, if the opening area of the ventilation section is controlled in accordance with the situation, there is an advantage that noise can be reduced and the heat balance of the engine can be kept good, but the opening area of the ventilation section is made variable. If a mechanism is provided, there is a problem that the configuration becomes more complicated and the engine room becomes larger.

The present invention has been made in view of the above points, and an object of the present invention is to make the opening area for ventilation variable without providing a mechanism for changing the opening area in the ventilation part. To be able to do it.

[0007]

In order to achieve the above-described object, the present invention provides an engine and a radiator in an engine room of a construction machine, and a cooling fan for supplying cooling air to the radiator. A ventilation portion is provided in an engine cover having an opening / closing cover constituting an engine room, so that when the cooling fan rotates, outside air is taken in from the front side of the radiator and discharged from the rear side of the radiator, A cover opening / closing means for opening / closing the opening / closing cover, a cooling water temperature detecting means for detecting a temperature of the engine cooling water, and a possibility that the engine cooling water exceeds a predetermined set temperature by the cooling water temperature detecting means. Control means for controlling the cover opening / closing means to open the opening / closing cover when detecting the It is an aspect of the.

Here, the cover that can be opened and closed may be a side cover, but in the case of a swingable machine, an upper openable cover that opens upward is more advantageous. Opening and closing of the cover opening and closing means can be performed by, for example, a hydraulic cylinder or the like. However, since a construction machine is usually equipped with a battery, it is not driven by an electric motor using the battery as a power source. It is preferable that the pinion is rotated by the electric motor, a rack is provided on the opening / closing cover, and the rack and the pinion are meshed with each other. When the opening / closing stroke of the opening / closing cover is from a fully closed state to a fully opened state where the opening is made to an angle through which an operator can pass, the operation of opening and closing the opening / closing cover for maintenance or the like can be automatically performed. Further, an outside air temperature detecting means is provided to determine how much the opening / closing cover should be opened when it is detected that the temperature of the engine cooling water has exceeded or is likely to exceed the set temperature. If the configuration is such that the opening degree of the opening / closing cover is changed by calculating based on the detection signal from the engine, the temperature of the engine cooling water can be quickly and reliably reduced to a predetermined value, and a sudden temperature decrease can be caused. Never.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a hydraulic excavator as an example of a construction machine. In the drawing, reference numeral 1 denotes a lower traveling body, and 2 denotes an upper revolving superstructure. The lower traveling unit 1 has a pair of right and left crawler tracks.
Is rotatably mounted on the lower traveling body 1. A driver's cab 3 and a front working mechanism 4 are installed on the upper revolving unit 2, and an operator performs traveling by the lower traveling unit 1, turning of the upper revolving unit 2, and operation of the front working mechanism 4 in the driver's cab 3. Can be. FIG. 1 shows only a part of the boom as the front working mechanism 4,
An arm is attached to the tip of the boom, and a front attachment such as a bucket is attached to the tip of the arm.

The running, turning, operation of the front working mechanism and the like are performed by a hydraulic actuator such as a hydraulic motor or a hydraulic cylinder. Therefore, a hydraulic pump is provided to supply pressure oil to each of the hydraulic actuators, and an engine for driving the hydraulic pump is also mounted. These hydraulic pumps and engines, as well as devices such as directional control valves, fuel tanks and hydraulic oil tanks, are installed on the upper revolving unit 2, but these devices are installed behind the cab 3 in order to install these devices. Is formed. Among the above-described devices, the tanks are installed so as to be exposed to the outside, but the devices other than the tanks are disposed in a building whose surroundings are covered with a wall, and the building forms a machine room 5. You.

[0011] Of the various devices provided in the machine room 5, the engine is large and generates a large amount of heat, so that it is installed in an independent engine room. FIG. 2 shows a schematic configuration of the engine room. In the figure, reference numeral 10 denotes an engine room, which is surrounded by a wall 11 and is substantially closed. An engine 12 and a radiator 13 are arranged inside the engine room 10. A cooling fan 14 is provided for flowing cooling air to the radiator 13, and the cooling fan 14 is driven by the engine 12. . Incidentally, an oil cooler may be installed together with the radiator 13. The engine 12 is the hydraulic pump 1
5 for driving the hydraulic pump 1
5 is connected to the engine 12.

The engine cooling water is circulated between the radiator 13 and the engine 12. The engine cooling water is supplied to the engine 12, and after cooling the engine 12, the engine cooling water having an increased temperature is supplied to the radiator 13. The engine 12 is refluxed and cooled to a predetermined temperature state by the radiator 13, so that the engine 12 does not overheat. The cooling fan 14 is connected to the radiator 1
3 for supplying cooling air to the radiator 13, and for this purpose, the engine room 1
Side wall 11a and upper fixed wall 11b constituting the wall 11
And the upper opening / closing cover 11c and the lower cover 11d are provided with ventilation portions 20, 21, respectively. Vent section 20
Is an inflow side ventilation portion formed on the side wall 11a and the upper fixed wall 11b on the front side of the radiator 13 in the engine room 10 to take in outside air.
1 is an upper opening / closing cover 11 on the rear side of the engine 12
c and the exhaust side ventilation portion formed in the lower cover 11d. Therefore, when the cooling fan 14 is operated, the outside air is taken in from the inflow side ventilation part 20, and after the flow toward the radiator 13 is formed, the airflow to be discharged from the exhaust side ventilation part 21 is generated in the engine room 10. It is formed.

Here, from the viewpoint of the cooling efficiency of the radiator 13, it is advantageous to increase the opening area of the ventilation sections 20, 21. However, if the opening area is increased without any noise, a large noise is generated. From the viewpoint, the opening area of these ventilation portions 20 and 21 cannot be so large.
The opening areas of the ventilation sections 20 and 21 are set so that the noise is reduced while maintaining the heat balance of the engine 12. However, for example, when the engine 12 is operated for a long time while a large load is acting on the engine 12,
The temperature inside the engine room 10 rises, the cooling efficiency decreases, and the engine 12 may enter an overheat state. In such a case, even if the noise problem is sacrificed to some extent, it is necessary to increase the area of the ventilation opening of the engine room 10 to increase the cooling efficiency.

The engine room 10 is composed of an engine cover surrounded by a wall.
The side wall 11a and the upper opening / closing cover 11c are configured to be openable and closable so that maintenance, inspection, repair, and the like of the radiator 13 and the like can be performed. The upper opening / closing cover 11c is connected to the upper fixed wall 11b by a hinge 22. Therefore, by rotating the upper opening / closing cover 11c upward about the hinge 22, the upper part of the engine room 10 is opened, and a required It is configured to perform maintenance work. Therefore, in the present invention, in order to increase the opening area for ventilation of the engine room 10, the upper opening / closing cover 11c that can be opened / closed is used. For this purpose, a mechanism for automatically opening and closing the upper opening / closing cover 11c is provided. In addition, the opening / closing stroke of the upper opening / closing cover 11c ranges from a fully closed state to a fully opened state which is an angle at which a worker can enter the engine room 10 in order to smoothly perform maintenance in the engine room 10. I have.

As an opening / closing mechanism of the upper opening / closing cover 11c, there is provided an electric motor 30 which can be rotated forward and backward, and this electric motor 30 is fixedly held by a partition wall defining the engine room 10. A pinion 31 is connected to the output shaft of the electric motor 30.
Is engaged with the rack 32, and the upper end of the rack 32 is fixed to the inner surface of the upper opening / closing cover 11c by welding or the like. The rack 32 is formed in an arc shape, and the center of the arc is the position of the hinge 22, which is the opening / closing center position of the upper opening / closing cover 11c. Thus, when the pinion 31 is rotated, the rack 32 rotates vertically, and the upper opening / closing cover 11c to which the rack 32 is connected opens and closes. Here, the opening / closing stroke of the upper opening / closing cover 11c by the rack-pinion mechanism is from the fully closed position covering the upper part of the engine room 10 to the fully open state shown by the imaginary line as shown by the solid line in FIG. I have. And the upper opening / closing cover 11
In the fully open state of c, the operator can inspect the inside of the engine room 10 and enter the inside of the engine room 10.

As shown in FIG. 3, power to the electric motor 30 is supplied from a battery 33 installed in a hydraulic shovel. The electric motor 30 includes a servo circuit 34.
Are connected to the servo circuit 34, and a control means 35 is provided for inputting a control signal to the servo circuit 34. Control means 35
Determines whether or not to open the upper opening / closing cover 11c based on the temperature of the engine cooling water, and determines the degree of opening when the upper opening / closing cover 11c is opened based on the temperature of the outside air. A signal corresponding thereto is input to the servo circuit 34 of the electric motor 30. As a result, the operation of the electric motor 30 is controlled, and the opening of the upper opening / closing cover 11c is adjusted. For this purpose, a cooling water temperature sensor 36 for detecting the temperature of the engine cooling water in the engine 12 or the radiator 13 and an outside air temperature sensor 37 for detecting the outside air temperature are provided. The detection signal from 38 is taken into the control means 35.

The electric motor 30 can also be operated manually. For this purpose, a manual operation means 38 having a dial 38a is provided in the cab 3 and a mode changeover switch 39 for switching between an automatic opening / closing mode and a manual opening / closing mode is provided. When the dial 38a of the manual control means 38 is turned, the mode changeover switch 39 switches from the automatic opening / closing mode to the manual opening / closing mode.
Can be operated in a direction to open or close the upper opening / closing cover 11c.

With the above configuration, when the temperature of the engine cooling water rises above a predetermined set value, the upper opening / closing cover 11c is automatically opened as shown in FIG. To increase the cooling efficiency of the engine cooling water. This makes it possible to improve the heat balance of the engine 12 and prevent the engine 12 from being damaged or broken down.

Therefore, as shown in FIG. 5, the control means 35 _supplies the upper limit temperature T _max of the engine cooling water, preferably the upper limit temperature T _max and the lower limit temperature T _min, and the standard temperature T _reg.
Are set in advance. Here, the upper limit temperature _Tmax , the lower limit temperature _Tmin , and the standard temperature _Treg are set based on the temperature at which the engine 12 operates properly. For example, Engine 1
2 is 105 ° C. when the temperature at which the most suitable operating state is reached is ± 5 ° C. with respect to this temperature, the standard temperature T _{reg is set} to 105 ° C., and the upper limit temperature T _max To 110 ° C. and the lower limit temperature T _min to 100 ° C.

The control means 35 takes in the engine cooling water temperature from the cooling water temperature sensor 37 at every time interval t. At the measurement time t _n , the temperature of the engine cooling water is ΔT, At time t _n−1 , when the temperature of the engine cooling water is T ₀ , ΔT + (ΔT−T
₀₎ = T _s> becomes a T _max, if the temperature of the engine cooling water as it continued to rise, the next measurement time t _{n + 1,} so that the temperature of the engine cooling water will past the T _max . Therefore, when it becomes a T _s> T _max by measuring the time t _n is the electric motor 30 is operated, by opening the top lid 11c, increasing the open area for ventilation. As a result, the cooling efficiency of the engine cooling water is improved, so that at least the temperature ΔT of the engine cooling water does not exceed _Tmax, and the temperature of the engine cooling water actually decreases. Then, when the temperature of the engine cooling water drops to the standard temperature T _reg , the electric motor 30 is reversed to close the upper opening / closing cover 11c. As a result, when the temperature of the engine cooling water may rise beyond the set range, the upper opening / closing cover 1 of the engine room 10 may be kept for a minimum necessary time.
By opening 1c, cooling efficiency can be improved and noise leakage can be suppressed to a minimum.

By the way, the degree of the temperature drop of the engine cooling water when the upper opening / closing cover 11c is opened depends on the outside air temperature. The temperature of the cooling water drops rapidly. As a result, the load due to heat fluctuation of the engine 12 is significantly increased, and in severe cases, the engine cylinder may be damaged. On the contrary,
When the outside air temperature is high, a substantial decrease in temperature cannot be expected if the opening degree of the upper opening / closing cover 11c is small. Therefore, when opening the upper opening / closing cover 11c, the opening degree is changed according to the outside air temperature. It is for this reason that the control means 35 takes in information on the outside air temperature from the outside air temperature sensor 37, and the opening of the upper opening / closing cover 11c is determined based on the signal from the outside air temperature sensor 37. Therefore, the relationship between the outside air temperature and the degree of opening of the upper opening / closing cover 11c is set in advance and stored in the control means 35.

Therefore, a procedure for controlling the temperature of the engine cooling water will be described below with reference to the flowchart shown in FIG. Here, as described above, since the lower limit temperature T _min of the engine cooling water is set, it is not necessary to perform the control by the control unit 35 until the lower limit temperature T _min is exceeded. However, since the temperature of the engine cooling water is constantly detected by the cooling water temperature sensor 37, it is not always necessary to set the lower limit temperature _Tmin .

[0023] In Thus, in step 1, the actual temperature ΔT of the engine cooling water it is determined whether or not exceeding the lower limit temperature T _min is carried out. The temperature of the engine cooling water is the lower limit temperature T
_If it exceeds _min , the temperature control of the engine cooling water by the control means 35 starts. That is, information about the temperature ΔT of the engine cooling water is fetched from the cooling water temperature sensor 36 every time t, and ΔT is calculated from this temperature ΔT and the temperature T ₀ measured last time.
+ (ΔT-T ₀₎ = performs calculation of T _s (step 2).
Then, in step 3, by comparing the T _s and T _max, it is determined whether T _s> T _max. T _s <T
If it is _max , this calculation and comparison are repeated at every predetermined time t. However, _if T _s > T _max at the measurement time t _n , ΔT> T _max may be satisfied at the next measurement time t _{n + 1.} Then, the electric motor 30 is operated, and the upper opening / closing cover 11
c will open.

First, information on the outside air temperature from the outside air temperature sensor 37 is fetched, and the data on the relationship between the outside air temperature preset in the control means 35 and the opening degree of the upper opening / closing cover 11c is obtained from the upper opening / closing cover 11c. The opening of 11c is determined (step 4). And the upper opening / closing cover 11c
Is determined, the electric motor 35 is operated at that stage to open the upper opening / closing cover 11c by the set angle (step 5). When the upper opening / closing cover 11c is opened at an appropriate opening degree and the opening area for ventilation increases, the flow rate of the cooling air to the radiator 13 increases, so that the temperature of the engine cooling water detected by the cooling water temperature sensor 36 decreases. become.

Therefore, at every time interval t, the cooling water temperature sensor 3
6 indicates that the engine cooling water temperature ΔT is the optimum temperature T
_When it is detected that the _voltage has decreased to _reg (step 6), the electric motor 35 is operated to operate the upper opening / closing cover 1.
1c is closed (step 7). Thus, when the engine cooling water is _likely to be higher than the upper limit temperature _Tmax , the upper opening / closing cover 11c is opened at a required opening degree for a required time, and an opening area for ventilation is increased. When the temperature returns to the optimum temperature _Treg , the upper opening / closing cover 11c
Will be closed. Therefore, the heat balance of the engine 12 becomes extremely good, and the opening time of the upper opening / closing cover 11c can be suppressed to a minimum in order to lower the temperature, and the generation of noise can be suppressed to a minimum. Since the temperature T _reg of the engine cooling water is higher than the lower limit temperature T _min , the process returns to step 1 and the operation of monitoring and controlling the temperature of the engine cooling water is repeated.

The upper opening / closing cover 11c also has a function of protecting dust and the like from entering the engine room 10. As described above, when the upper opening / closing cover 11c is opened during the operation of the hydraulic excavator, dust may enter therefrom. However, as described above, since the upper opening / closing cover 11c is opened only for a time necessary for lowering the temperature of the engine cooling water and at a required opening degree, the possibility of dust entering is minimized. Is suppressed. In addition, the portion where the upper opening / closing cover 11c opens is the rear side of the engine 12, and since this portion has the highest temperature in the engine room 10, the internal pressure is high. Therefore, when the upper opening / closing cover 11c is opened, Since the exhaust from the engine room 10 to the outside air is promoted, there is substantially no risk of dust entering.

The reason why the open / close cover is provided on the upper part of the wall constituting the engine room 10 is for maintenance in the engine room 10. That is,
Maintenance and inspection of the equipment such as the engine 12 and the radiator 13 provided in the engine room 10 and necessary repairs,
An upper opening / closing cover 11c is provided to enable cleaning or the like. In order to make maintenance as easy as possible, most of the wall on the upper side of the engine room 10 is used as the upper opening / closing cover 11c.
Therefore, the upper opening / closing cover 11c is heavy,
It becomes difficult to open and close the upper opening / closing cover 11c during maintenance.

The upper opening / closing cover 11c can be opened and closed by the electric motor 30, so that the upper opening / closing cover 11c can be opened and closed by driving the electric motor 30 by operating the manual operation means 38. Maintenance is performed with the engine 12 stopped, but the upper opening / closing cover 11c
Uses the battery 33 as a power source. Therefore, even when the engine 12 is stopped, the electric motor 30 can be operated as long as the electric power is stored in the battery 33. In addition, since the upper opening / closing cover 11c is opened to a fully opened state beyond a stroke necessary for increasing the opening area for ventilation, for example, a worker performing maintenance can move the engine room 10 from the upper opening / closing cover 11c side. Can get inside. Note that the upper opening / closing cover 11c
When is fully opened, it is preferable to provide a stopper for holding the upper opening / closing cover 11c at this position.

[0029]

Since the present invention is constructed as described above, the opening area for ventilation can be increased by opening the cover which can be opened and closed for maintenance and the like. Since it is not necessary to change the opening area of the ventilation section provided on the wall surface of the engine room in order to change the area, there is an effect that the configuration can be significantly simplified and downsized.

[Brief description of the drawings]

FIG. 1 is an external view of a hydraulic shovel as an example of a construction machine provided with an engine cooling device of the present invention.

FIG. 2 is a sectional view of an engine room.

FIG. 3 is a configuration explanatory view of an opening / closing mechanism of an upper opening / closing cover.

FIG. 4 is a diagram showing a state in which an opening area for ventilation is increased.
It is sectional drawing similar to.

FIG. 5 is an explanatory view of the principle when controlling the temperature of the engine cooling water.

FIG. 6 is a flowchart illustrating a procedure for executing temperature management of engine cooling water.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving superstructure 5 Machine room 10
Engine room 11 wall 11c
Upper opening / closing cover 12 Engine 13
Radiator 14 cooling fan 20,
21 ventilation part 30 electric motor 31
Pinion 32 Rack 33
Battery 35 Control means 36
Cooling water temperature sensor 37 Outside temperature sensor 38
Manual operation means

Claims (7)

[Claims] An engine, a radiator, and a cooling fan for supplying cooling air to the radiator are installed in an engine room of a construction machine, and a ventilation portion is provided in an engine cover having an opening / closing cover forming the engine room. hand,
A cover opening / closing means for opening / closing the opening / closing cover, and a cooling water temperature for detecting a temperature of engine cooling water, wherein the outside air is taken in from the front side of the radiator and discharged from the rear side of the radiator when the cooling fan rotates. Control means for opening the open / close cover by operating the cover opening / closing means when the cooling water temperature detecting means detects that the engine cooling water has exceeded or may exceed a predetermined set temperature. An engine cooling device for a construction machine, comprising: 2. The engine cooling device for a construction machine according to claim 1, wherein the opening / closing cover is an upper opening / closing cover of an engine room. 3. The engine cooling device for a construction machine according to claim 1, wherein the cover opening / closing means includes an electric motor driven by a battery installed in the construction machine as a driving means. 4. The construction machine according to claim 3, wherein said cover opening / closing means comprises a pinion driven by said electric motor, and a rack connected to said opening / closing cover and meshing with said pinion. Engine cooling system. 5. The engine cooling device for a construction machine according to claim 1, wherein an opening / closing stroke of the opening / closing cover is from a fully closed state to a fully opened state where the opening is opened to an angle through which an operator can pass. 6. The cover opening / closing means can be switched between an automatic operation mode for opening and closing according to the temperature of engine cooling water and a manual operation mode for operating the cover opening / closing means according to manual operation. The engine cooling device for a construction machine according to claim 5, wherein: 7. An outside air temperature detecting means for detecting an outside air temperature is provided, and a detection signal from the outside air temperature detecting means is taken into the control means. The engine cooling device for a construction machine according to claim 1, wherein the opening of the cover is adjusted.