JP3202222B2 - Overheating prevention equipment for construction machinery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a construction machine such as a hydraulic shovel, a crane, and the like, and more particularly to an improvement in a device for preventing overheating of an internal combustion engine mounted in an engine room.

2. Description of the Related Art For example, in a construction machine such as a hydraulic shovel, the inside of an engine room is configured as shown in FIG. 4, reference numeral 21 denotes an internal combustion engine mounted in an engine room 20, and reference numeral 22 denotes an internal combustion engine.
A cooling fan driven by 21; a radiator 23 provided in front of the cooling fan 22; a hydraulic pump 24 driven by the internal combustion engine 21; An intake port 26 provided on the upper wall is an exhaust port provided on the wall of the engine room 20 at a position above the hydraulic pump 24. Hydraulic pump 24
Is driven by the internal combustion engine 21 such as a diesel engine, the capacity of the radiator 23 for cooling the cooling water of the internal combustion engine 21 and the hydraulic oil for the hydraulic pump 24 driven by the internal combustion engine 21, The size and rotation speed of the suction-type cooling fan 22 driven by 21, the intake area and exhaust area of the engine cover 20, the absorption horsepower of the hydraulic pump 24, etc. Is set not to overheat.

[Problems to be Solved by the Invention] However, if the internal combustion engine is continuously used under a heavy load in which a large amount of work is performed in a short time, the internal combustion engine is overheated. Also, in order to prevent overheating even when used under heavy load, it is necessary to increase the capacity of the radiator, increase the size of the cooling fan, and increase the intake and exhaust area of the engine cover. However, this greatly increases the cost.
Further, if the intake / exhaust area of the engine cover is increased, the noise of the internal combustion engine leaks to the outside, so that the noise increases.

The present invention has been made in view of the above circumstances, and has as its object to increase the capacity of a radiator, the size and rotation speed of a cooling fan, the intake / exhaust area of an engine cover, and the like, and to provide a hydraulic pump. It is an object of the present invention to provide an overheating prevention device for a construction machine that can prevent overheating of an internal combustion engine during heavy load work without reducing absorption horsepower.

Means for Solving the Problems In order to achieve the above object, the present invention provides an internal combustion engine, a suction type cooling fan driven by the internal combustion engine, and a cooling water blown by the cooling fan to cool the internal combustion engine. And a radiator that cools hydraulic oil for a hydraulic pump driven by the internal combustion engine, and a construction machine mounted in an engine room, detects a cooling water temperature or an engine oil temperature of the internal combustion engine, and outputs a signal corresponding to the detected temperature. A temperature sensor to be output, an exhaust fan for discharging the air sucked into the engine room and passing through the radiator to the outside of the engine room, and a signal from the temperature sensor are input, and the rotation speed of the exhaust fan is input. A control device for controlling, when the thermal condition of the engine is equal to or higher than a predetermined value, this control device The exhaust fan is determined at a signal from a temperature sensor, and the exhaust fan is controlled to an arbitrary rotation speed for preventing overheating of the internal combustion engine.

[Operation] According to the above configuration, when the thermal state of the engine is equal to or more than a predetermined value during heavy load work, the exhaust fan is rotated at an arbitrary rotation speed, and the engine inside the engine room passing through the radiator is rotated. By forcibly discharging the high-temperature air to the outside of the engine room and increasing the amount of air passing through the radiator by the cooling fan based on this, overheating of the internal combustion engine is prevented.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In the figure, the same components as those in FIG. 4 are denoted by the same reference numerals. Inside the engine room 20, an internal combustion engine 21, a cooling fan 22 driven by the internal combustion engine 21, a radiator 23 provided in front of the cooling fan 22, and a hydraulic pump 24 driven by the internal combustion engine 21 are provided. An intake port 25 is provided at a position in front of the radiator 23 in an upper wall of the engine room 20, and an exhaust port 26 is provided in a position above the hydraulic pump 24 in the wall of the engine room 20. The exhaust fan 1 is attached to the position of the exhaust port 26 in the engine room 20. An electric circuit for driving the exhaust fan 1 is configured as shown in FIG. 2, and a control device 2 controls the number of revolutions of the exhaust fan 1, and the control device is connected to a power supply 3. At the same time, it is connected to a sensor (temperature sensor) 4 which is attached to the internal combustion engine 21 and detects a cooling water temperature of the internal combustion engine 21 (or an oil temperature of the internal combustion engine 21) and outputs a signal corresponding thereto.

In the above configuration, when a general load is applied by the hydraulic pump 24, after cooling air is drawn into the engine room 20 from the intake port 25 through the radiator 23 by the cooling fan 22 driven by the internal combustion engine 21, In the engine room 20, it flows around the internal combustion engine 21 and the hydraulic pump 24 as shown by arrows in FIG. 1 to cool them, and then is discharged from the exhaust port 26 to the outside of the engine room 20.
The opening area of the exhaust port 26 is limited to an appropriate size in order to prevent noise in the engine room 20 from leaking outside. For this reason, at the time of heavy load work by the hydraulic pump 24, the high-temperature cooling air accumulates in the engine room 20, and an internal pressure is generated. At this time, the internal combustion engine 21
When the temperature of the cooling water (or the oil temperature of the internal combustion engine 21) rises and a signal corresponding thereto is input to the control device 2 by a sensor (temperature sensor) 4, the input value is If it is equal to or greater than the predetermined value, the exhaust fan 1 is rotated at an arbitrary rotation speed to
The internal cooling air that has become high temperature is forcibly discharged to the outside and the internal pressure is released. As a result, the amount of cooling air passing through the radiator 23 is increased, the heat radiation is improved, and overheating of the internal combustion engine 21 is prevented.

As the control method of the exhaust fan 1 by the control device 2, various methods such as a method of increasing the rotation speed of the exhaust fan 1 in proportion to a rise in the temperature of the internal combustion engine 21 and a method of increasing the increase amount stepwise are considered. However, FIG. 3 shows an example of this, in which a temperature switch 5 is used as a sensor 4 and a relay 6 is used as a control device 2. The cooling water temperature of the internal combustion engine 21 (or the internal combustion engine 21
When the oil temperature rises and the value exceeds a predetermined value, the temperature switch 5 is turned on, and the exhaust fan 1 is connected to the power supply 3 to excite the relay 6, so that the exhaust fan 1 is set in advance. It rotates at the rotation speed.

In the above-described embodiment, the exhaust fan is shown as an example of electric drive. However, it is needless to say that the present invention can be similarly realized in the case of hydraulic drive or pneumatic drive.

[Effects of the Invention] According to the overheating prevention device for a construction machine of the present invention described above, the hydraulic pump can be used without increasing the capacity of the radiator, the size and the rotation speed of the cooling fan, the intake / exhaust area of the engine cover, and the like. Without lowering the absorption horsepower of
It is possible to prevent overheating of the internal combustion engine during heavy load work. In addition, since the heat radiation amount of the radiator can be appropriately controlled according to the heat state of the internal combustion engine, the life of the internal combustion engine can be extended and a failure can be prevented. Furthermore, since the amount of cooling air can be increased without increasing the exhaust port area of the engine cover, when the same amount of cooling air is sucked and exhausted, the amount of leakage of noise of the internal combustion engine to the outside is reduced, Low noise can also be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating an embodiment of an overheating prevention device for a construction machine according to the present invention, FIG. 2 is an electric circuit diagram showing a drive circuit of an exhaust fan shown in FIG. 1, and FIG. FIG. 4 is an electric circuit diagram showing an example of the control device shown in FIG.
FIG. 1 is a schematic cross-sectional view for illustrating a conventional overheat prevention device for a construction machine. 1 ... exhaust fan, 2 ... control device, 3 ... power supply, 4 ...
… Sensor, 20… Engine room, 21… Internal combustion engine, 22
… Cooling fan, 23… radiator, 24… hydraulic pump, 25… intake port, 26… exhaust port.

Claims (1)

(57) [Claims] An internal combustion engine, a suction-type cooling fan driven by the internal combustion engine, and cooling of cooling water of the internal combustion engine and hydraulic oil for a hydraulic pump driven by the internal combustion engine which are blown by the cooling fan. In a construction machine having a radiator mounted in an engine room, a temperature sensor that detects a cooling water temperature or an engine oil temperature of the internal combustion engine and outputs a signal corresponding to the temperature, and is sucked into the engine room and passes through the radiator An exhaust fan for discharging the exhausted air to the outside of the engine room, and a control device that receives a signal from the temperature sensor and controls the number of revolutions of the exhaust fan. When it is more than the predetermined value,
This is determined by a signal from the temperature sensor, and the exhaust fan is controlled to an arbitrary rotation speed for preventing overheating of the internal combustion engine, wherein an overheating prevention device for a construction machine is provided.