JP2004293508A - Flow control device of cooling water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow control device of cooling water which is miniaturized to minimize drive loss and which can suppress occurrence of cavitation. <P>SOLUTION: In the flow control device, cooling water is discharged from a water pump 9 activated by rotation of an engine 1. The cooling water passes through passages 6, 8, 4 connected to the water pump 9 to be circulated to the water pump 9. A solenoid valve 10 for adjusting a passage area of the passage 4 is provided to the passage 4 arranged on a discharging side 9b of the water pump. The solenoid valve 10 is controlled by employing a control means 11 in a direction to narrow the passage area in accordance with increase in engine rotation speed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flow control device for cooling water supplied to an engine from a water pump operated by rotation of the engine.
[0002]
[Prior art]
In a water-cooled engine, cooling water is circulated between the engine and a radiator using a water pump operated by rotation of the engine. In the case of a water pump that obtains a driving force from such an engine, the rotation speed of the water pump itself increases as the rotation speed of the engine increases, and the discharge amount increases. As a cooling performance of the engine, generally, a pump capable of obtaining a discharge amount that can obtain a desired cooling performance at a low speed and a high load is selected.
[0003]
[Problems to be solved by the invention]
However, if a water pump capable of obtaining a discharge amount in consideration of cooling performance at low speed and high load is set, in a high engine speed region, the discharge amount required for engine cooling will be exceeded and supply will be excessive. This causes the pump to rotate to discharge unnecessary cooling water, resulting in drive loss. In recent years, an electric water pump may be used instead of the operation by the driving force from the engine. In this case, the problem of drive loss is eliminated, but in general, in the case of an electric pump, the pump capacity is increased to obtain a discharge amount equivalent to that of an engine-driven pump, resulting in an increase in size. In addition, an increase in the size of the pump causes a new problem of securing a mounting space.
In a water pump, when the number of rotations becomes high, the water pressure on the pump suction side decreases, and dissolved air is separated due to an increase in suction negative pressure, and bubbles are generated. When these bubbles collide with the turbine of the pump, so-called captions occur. For this reason, suppressing the generation of caption is also an important factor in cooling the engine.
SUMMARY OF THE INVENTION An object of the present invention is to provide a cooling water flow control device which is small in size, has small driving loss, and can suppress generation of caption.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a flow rate control of cooling water discharged from a water pump operated by rotation of an engine and circulated to the water pump through a flow path connected to the water pump through the engine. In the device, a valve for adjusting the flow passage area of this flow passage is provided in the flow passage located on the discharge side of the water pump, and the valve is controlled by a control means in a direction to decrease the flow passage area as the engine speed increases. When the control is performed using this, as the engine speed increases, the cross section of the flow path becomes narrower and the flow path resistance on the pump discharge side increases. For this reason, while maintaining the cooling performance at low speed and high load, the pump discharge amount on the high speed side of the pump rotation is reduced, and the load due to the rotation of the pump is reduced, so that the drive loss can be reduced. Further, since the discharge amount of the water pump is reduced, the suction negative pressure on the pump suction side is reduced, so that the generation of bubbles is reduced and the generation of caption can be suppressed.
[0005]
In performing the above control, the engine speed is detected by an engine speed detecting unit, and the control unit compares the detected engine speed from the engine speed detecting unit with a predetermined engine speed, and detects the engine speed. If the valve is controlled in a direction to reduce the flow path area when the rotation speed is equal to or higher than the predetermined engine rotation speed, the flow passage cross section becomes narrower at the predetermined engine rotation speed, and the flow resistance on the pump discharge side increases. For this reason, while maintaining the cooling performance at low speed and high load, the pump discharge amount on the high speed side of the pump rotation is reduced, and the load due to the rotation of the pump is reduced, so that the drive loss can be reduced. Further, since the discharge amount of the water pump is reduced, the suction negative pressure on the pump suction side is reduced, so that the generation of bubbles is reduced and the generation of caption can be suppressed.
[0006]
When performing the above control, the load information of the engine is further detected by the load information detecting means, and the control means determines the state of the engine load based on the load information from the load information detecting means. Control may be performed to increase the engine speed. As the engine load increases, the specified engine speed increases, narrowing the valve.This reduces the load associated with pump rotation while maintaining cooling performance at low speeds and high loads, further reducing drive loss. can do.
[0007]
In order to achieve the above object, according to the present invention, a flow rate control of cooling water discharged from a water pump operated by rotation of an engine and circulated to the water pump through a flow path connected to the water pump through the engine. In the device, a flow path located on the discharge side of the water pump is provided with flow path adjusting means for reducing the area of the flow path in accordance with an increase in the flow rate of the cooling water flowing through the flow path, and serves as a parameter correlated to the pump discharge amount. The change in the engine speed is read from the change in the flow rate of the cooling water in the flow path located on the discharge side. When the flow rate of the cooling water increases, the flow path adjusting means narrows the cross section of the flow path and increases the flow resistance on the pump discharge side. I do. For this reason, while maintaining the cooling performance at low speed and high load, the pump discharge amount on the high speed side of the pump rotation is reduced, and the load due to the rotation of the pump is reduced, so that the drive loss can be reduced. Further, since the discharge amount of the water pump is reduced, the suction negative pressure on the pump suction side is reduced, so that the generation of bubbles is reduced and the generation of caption can be suppressed.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The cooling water flow control device shown in FIG. 1 includes a water pump 9 operated by rotation of the engine 1 and flow paths 4, 5, 6, and 8 connected from the water pump 9 to the water pump 9 via the engine 1. The cooling water is circulated to the water pump 9 through these flow paths. A cooling water passage 2 is formed inside the engine 1, and one of the cooling water passages 2 is connected to a flow path 4 serving as a supply side of cooling water to the engine 1, and the other is connected to a flow path 6 serving as a discharge side. Have been. The channel 8 and the channel 5 are connected to one of the channels 4 via the thermostat 3, respectively. The thermostat 3 changes the flow of the cooling water from the flow path 8 to the flow path 4 or the flow path 5. The flow path 5 is a bypass flow path that guides the cooling water to the flow path 6 while avoiding the engine 1 when the thermostat 3 operates. The water inlet side of the radiator 7 is connected to the flow path 6. The flow path 8 is connected to the discharge side of the radiator 7. A pressure regulating valve 15 is provided on the water inlet side of the radiator 7, and is configured so that the pressure supplied to the radiator 7 is constant.
[0009]
The water pump 9 is disposed in the flow path 4 such that the suction side 9 a is located on the thermostat 3 side and the discharge side 9 b is located on the inflow side of the engine 1. The water pump 9 is a direct-acting pump that operates by transmitting the rotation of the engine from a crankshaft of an engine (not shown) via a drive transmission means such as a pulley and belt or gear train (not shown) or a sprocket and a chain. In addition, the configuration is such that the rotation of the engine 1 itself increases as the rotation of the engine 1 increases.
[0010]
With such a flow path configuration, when the engine 1 starts and the water pump 9 operates, a turbine in a pump (not shown) rotates to discharge cooling water toward the engine 1. The discharged cooling water is sent from the flow path 4 to the flow path 6 and the radiator 7 via the cooling water path 2, where it is cooled by running air or air blown by rotation of a fan. The cooled cooling water is supplied to the thermostat 3 through the flow path 8. Then, the amount of cooling water flowing into the flow path 4 from the flow path 8 and the flow path 5 is adjusted according to the state of the thermostat.
[0011]
Next, the configuration of the flow rate adjusting unit which is a main part of the present invention will be described. In the flow path 4 located on the discharge side of the water pump 9, an electromagnetic valve 10 that adjusts the flow path area of the flow path 4 by controlling its operation by the control unit 11 is disposed. The solenoid valve 10 is normally turned off. In this state, the flow path area of the flow path 4 is ensured so that the flow rate of the cooling water that can obtain the desired cooling performance can be ensured even at a low speed and a high load. Then, when turned on, it functions as a flow control valve acting in a direction to reduce the flow path area of the flow path 4.
[0012]
The control means 11 is composed of a known computer provided with a CPU and various memories. The control means 11 is connected to a crank angle sensor 12 as an engine speed detecting means for detecting the engine speed Ne, and an accelerator opening sensor 14 as a load information detecting means for detecting the engine load θa. In the present embodiment, the load information detecting means uses the accelerator opening sensor 14 for detecting the opening of the accelerator 13, but the means for detecting the opening of the throttle valve and the amount of intake air are used as the load information detecting means. May be.
[0013]
The control means 11 controls the operation of the solenoid valve 11 in a direction to reduce the flow passage area as the rotation speed of the engine 1 increases. That is, the control means 11 compares the detected rotation speed Ne from the crank angle sensor 12 with a predetermined engine rotation speed preset in a memory (not shown). The solenoid valve 11 is turned on to control the solenoid valve 11 in a direction to reduce the road area. The memory of the control means 11 determines the state of the engine load on the basis of the load information θa from the accelerator opening sensor 14 and controls the engine speed to be increased as the engine load increases, as shown in FIG. Is stored. That is, the control unit 11 controls the engine speed to operate (turn on) the solenoid valve 11 in accordance with the engine load.
[0014]
FIG. 2 is a characteristic diagram showing a relationship between the discharge amount of the water pump 9 and the driving work of the water pump 9. Generally, as the pump discharge increases, the shaft output also tends to increase. In the case of the direct-acting water pump 9, the rotation speed of the rotor is proportional to the engine rotation speed, and the discharge amount is substantially proportional to the rotor rotation speed. The inventor of the present application pays attention to the fact that the drive work of the water pump 9 is reduced by reducing the pump discharge amount from the characteristics shown in FIG. 2, and in order to reduce the pump discharge amount, an electromagnetic valve functioning as a flow rate regulating valve 10 is controlled by the control means 11.
[0015]
Hereinafter, one form of control by the control unit 11 will be described with reference to the flowchart shown in FIG. In step S1 of FIG. 4, Ne and θa, which are outputs from the sensors, are taken in. In step S2, the switching speed Ne1 according to the load information θa is selected from the map shown in FIG. In step S3, the detected rotation speed Ne is compared with the switching rotation speed Ne1. If the detected rotation speed Ne is equal to or higher than the switching rotation speed Ne1, the process proceeds to step S4, where the electromagnetic valve 11 is turned on, and the detected rotation speed Ne is determined. Does not exceed the switching speed Ne1, the routine proceeds to step S5, where the solenoid valve 11 is turned off.
[0016]
As described above, when the solenoid valve 11 is turned on when the engine speed is equal to or higher than the predetermined engine speed, the flow path area of the flow path 4 is reduced, so that the flow resistance on the pump discharge side is increased. For this reason, the pump discharge amount on the high-speed side of the pump rotation decreases, and the load associated with the rotation of the water pump 9 is reduced. Therefore, the configuration of the conventional water pump 9 can be used, and drive loss can be reduced. Further, since the discharge amount of the water pump 9 is reduced, the suction negative pressure on the suction side 9a of the pump is reduced, so that the generation of bubbles is reduced and the generation of caption can be suppressed. Further, the switching speed Ne1 for turning on the solenoid valve 11 is changed by the engine load information θa, that is, the engine speed is controlled so that the predetermined engine speed for narrowing the solenoid valve 11 with the increase of the engine load is increased. The drive loss at the time of low load and high rotation can be further reduced while maintaining the cooling performance at the time.
[0017]
FIG. 5 shows another embodiment of the present invention. The cooling water flow control device shown in FIG. 5 uses a water pump instead of the solenoid valve 11 of the cooling water flow control device shown in FIG. This is provided in the flow path 4 located on the discharge side 9b of the nozzle 9 and is not an electronic flow rate control but a mechanical flow rate control. The control means 11 and various sensors are not provided. Since the basic flow path configuration other than these is the same as the configuration in FIG. 1, its life is omitted here, and the configuration of the flow path adjusting means 20 and its operation will be described.
[0018]
As shown in FIG. 5, the flow path adjusting means 20 is a flow control valve having a ball valve 22 urged by a return spring 21 to a stopper 24 which determines an initial position inside an enlarged portion 21 provided in the flow path 4. is there. The enlarged portion 21 is formed such that its volume decreases from the discharge side 9b toward the engine 1. The stopper 24 has a ring shape and allows the cooling water discharged from the discharge side 9b to flow into the downstream side. When the flow rate of the cooling water flowing through the flow path 4 increases, the ball valve 22 moves rightward in the drawing against the spring force of the return spring 23 and moves so as to reduce the flow path area of the flow path 4. . That is, the spring force of the return spring 23 normally causes the ball valve 22 to abut against the stopper 24, and when the engine speed increases and the discharge amount from the water pump 9 increases, the flow area of the flow path 4 increases accordingly. It is adjusted to move to the right to make it narrower.
[0019]
According to such a configuration, a change in the engine speed is read from a change in the flow rate of the cooling water in the flow path 4 located on the discharge side 9b, which is a parameter correlated to the discharge rate of the water pump 9, and when the flow rate of the cooling water increases, As a result, the ball valve 22 of the flow path adjusting means 20 moves to the right and the cross section of the flow path is narrowed, so that the flow path resistance on the discharge side 9b of the water pump 9 increases. For this reason, while maintaining the cooling performance at low speed and high load, the pump discharge amount at the high speed side of the pump rotation is reduced, the load associated with the rotation of the pump is reduced, and the drive loss can be reduced. it can. Further, since the discharge amount of the water pump 9 is reduced, the suction negative pressure on the suction side 9a of the pump is reduced, so that the generation of bubbles is reduced and the generation of caption can be suppressed.
[0020]
In each of the above embodiments, the electromagnetic valve 11 and the flow rate adjusting means 20 are provided in the flow path 4 between the discharge side 9b of the water pump 9 and the engine 1, that is, the supply path of the cooling water to the engine 1. The electromagnetic valve 11 and the flow rate adjusting means 20 may be provided in the flow path 6 on the discharge side from the engine 1, or may be provided in the cooling water passage 2 inside the engine. In this case, since the pressure regulating valve 15 is disposed on the water inlet side of the radiator 7, the engine is located closer to the engine than the constant pressure valve, and the engine is located closer to the engine than the branch point between the flow path 6 and the flow path 5, that is, the cold supply water. Preferably, it is located upstream with respect to the flow.
[0021]
Although the ball valve type is used for the flow rate adjusting means 20, it goes without saying that other configurations may be used. For example, in a normal state, when the flow rate flowing through the flow path 4 is increased along the inner wall of the flow path 4, the flow path 4 protrudes into the flow path 4 to reduce the flow path area, thereby increasing the flow resistance. A tongue-shaped valve to be arranged may be arranged in the flow path 4 to serve as a flow rate adjusting means.
[0022]
【The invention's effect】
According to the present invention, as the engine speed increases, the flow path cross-section becomes narrower and the flow path resistance on the pump discharge side increases. The pump discharge amount at the pump side is reduced, and the load associated with the rotation of the pump is reduced, so that the drive loss can be reduced and the suction negative pressure at the pump suction side is reduced, resulting in less air bubbles. In addition, the occurrence of caption can be suppressed.
According to the present invention, when the rotation speed detected by the engine rotation detection means reaches a predetermined engine rotation speed, the flow passage cross section becomes narrower, the flow passage resistance on the pump discharge side increases, and the cooling performance at low speed and high load is reduced. While maintaining, the pump discharge amount on the high-speed side of the pump rotation is reduced, and the load accompanying the rotation of the pump is reduced, so that the drive loss can be reduced and the suction negative pressure on the pump suction side is reduced. The generation of bubbles is reduced, and the generation of caption can be suppressed.
According to the present invention, the predetermined engine speed at which the valve is narrowed with an increase in the engine load increases, so that the load accompanying the rotation of the pump is further reduced while maintaining the cooling performance at low speed and high load. In addition, drive loss can be further reduced.
According to the present invention, when the flow rate of the cooling water in the flow path located on the pump discharge side increases, the flow path cross-section is narrowed by the flow path adjusting means, the flow path resistance on the pump discharge side is increased, and low speed, high load While maintaining the cooling performance at the time, the pump discharge amount on the high-speed side of the pump rotation is reduced and the load associated with the rotation of the pump is reduced, so that the drive loss can be reduced and the suction load on the pump suction side can be reduced. The pressure is reduced and the generation of bubbles is reduced, so that the generation of caption can be suppressed.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a cooling water flow control device according to an embodiment of the present invention.
FIG. 2 is a characteristic diagram showing a relationship between a pump discharge amount and a pump driving work.
FIG. 3 is a diagram showing a change characteristic of an engine load and a predetermined engine speed.
FIG. 4 is a flowchart showing one form of control by the control means according to the present invention.
FIG. 5 is an overall configuration diagram of a cooling water flow control device showing another embodiment of the present invention.
FIG. 6 is an enlarged view showing one embodiment of a flow path adjusting unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 4 Flow paths 6, 8 located on the discharge side Flow path 9 Water pump 9b Discharge side 10 Solenoid valve 11 Control means 12 Engine speed detection means 14 Load information detection means 20 Flow path adjustment means

Claims (4)

A cooling water flow control device that is discharged from a water pump that is operated by rotation of an engine, and that is circulated to the water pump through a flow path connected to the water pump through the engine,
A valve that is provided in a flow path located on the discharge side of the water pump and adjusts a flow path area of the flow path;
Control means for controlling the valve in a direction to reduce the flow passage area in accordance with an increase in the rotation speed of the engine. The cooling water flow control device according to claim 1,
Having an engine speed detecting means for detecting the engine speed,
The control unit compares the detected rotation speed from the engine rotation speed detection unit with a predetermined engine rotation speed set in advance, and reduces the flow passage area when the detected rotation speed is equal to or higher than the predetermined engine rotation speed. A flow rate control device for cooling water, characterized by controlling the valve in a direction. The flow rate control device for cooling water according to claim 2,
A load information detecting unit that detects load information of the engine;
The control unit determines a state of an engine load based on load information from the load information detection unit, and increases the predetermined engine speed with an increase in the engine load. . A cooling water flow control device that is discharged from a water pump that is operated by rotation of an engine, and that is circulated to the water pump through a flow path connected to the water pump through the engine,
Cooling water provided in a flow path located on the discharge side of the water pump, and having flow path adjusting means for reducing a flow path area of the flow path as the flow rate of the cooling water flowing through the flow path increases. Flow control device.

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