JP2005220772A - Engine cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device capable of quickly changing the circulation of engine cooling water into a low temperature control state corresponding to the engine operating condition, especially corresponding to the changing from the light load condition into the heavy load condition, thereby especially quickly corresponding to the high load operation. <P>SOLUTION: A thermostat response valve 15 for high temperature and a thermostat response valve 16 for low temperature are connected to the position to intersect a bypass pipeline D midway along return pipelines C, E, F between a radiator 11 and an engine 10, and an electronically controlled valve 17 is connected upstream side of the thermostat response valve 16 for low temperature. Under a light load, the electronically controlled valve 17 closes to reflux cooling water only for the thermostat response valve 15 for high temperature. By changing the engine to the heavy load condtion, the electronically controlled valve 17 opens, and the thermostat response valve for high temperature closes to reflux cooling water from the radiator 11 for the thermostat response valve 16. The water temperature of cooling water is controlled with the thermostat response valve 16 for low temperature in a low temperature range. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an engine cooling apparatus, and more particularly to an engine cooling apparatus in which cooling water is circulated between an inside of an engine cooling jacket and a radiator.

  In general, an internal combustion engine such as a gasoline engine compresses an air-fuel mixture introduced into a cylinder, burns the air-fuel mixture with an ignition plug almost in synchronization with the piston reaching top dead center, and the piston expands by gas expansion. In addition to pushing back, the linear motion of the piston is transmitted to the crank portion of the crankshaft via the connecting rod, so that the crankshaft generates an output torque. Therefore, the cylinder intermittently causes a combustion explosion inside the cylinder, and the temperature of the cylinder rises.

  Therefore, the cooling head is provided between the water jacket and the radiator of the cylinder head and the cylinder block, and the cooling water is circulated between the water jacket and the radiator by the water pump, thereby utilizing the heat radiation effect of the radiator. Cooling is performed.

  In an engine equipped with such a water-cooled cooling device, if the pipe is connected so that the cooling water always circulates in the radiator, the warm-up operation cannot be performed when the temperature of the outside air is low, or the warm-up time Is longer than necessary. Therefore, a bypass pipe that bypasses the radiator is usually provided in the cooling pipe, and a thermostat switching valve is provided at a position where the bypass pipe and the circulation pipe intersect, and the cooling water is bypassed from the radiator according to the temperature of the cooling water. The temperature of the cooling water of the engine is kept almost constant by parallel or switching circulation with the pipe line.

  As such a thermostat type switching valve, a thermostat type switching valve as disclosed in JP-A Nos. 51-13036 and 2003-239744 is widely used.

However, an ordinary thermostat type switching valve has a function of switching its circulation path according to the temperature of the cooling water, and therefore, it does not always perform optimum switching control according to the state of the engine. That is, when the temperature of engine cooling water is lowered during normal driving at a low load, engine friction increases, fuel consumption increases, and the amount of harmful gas increases. Also, when switching suddenly from normal driving at low load to high load operation, the thermostat type switching valve maintains the temperature of the cooling water almost constant. There is a disadvantage that the water temperature cannot be changed.
Japanese Patent Laid-Open No. 51-13036 JP 2003-239744 A

  An object of the present invention is to provide an engine cooling device that can quickly and appropriately change the temperature of cooling water in accordance with the operating state of the engine.

  Another object of the present invention is to provide an engine cooling device that can quickly change the cooling water temperature in response to the switching of the pipeline when the engine load is switched from a low load to a high load. It is to be.

  Another object of the present invention is to provide an engine cooling apparatus that switches a cooling water circulation line in response to a change in the operating state of the engine and quickly switches the temperature control of the cooling water from a high temperature state to a low temperature state. Is to provide.

  Still another object of the present invention is to provide an engine cooling device including an electronic control valve that has good responsiveness and low power consumption.

  The above-described problems and other problems of the present invention will be clarified by the technical idea of the present invention and the embodiments thereof described below.

The main invention of the present application is an engine cooling apparatus in which cooling water is circulated between an inside of an engine cooling jacket and a radiator.
A high temperature thermostat type response valve and a low temperature thermostat type response valve are connected in parallel to the cooling water circulation line, and an electronic control valve is connected in series with the low temperature thermostat type response valve,
The engine water temperature is controlled by the high temperature thermostat type response valve, and when the engine load increases, the electronic control valve performs switching control so that cooling water flows through the low temperature thermostat type response valve. The present invention relates to an engine cooling device.

  Here, the electronic control valve may be connected to the upstream side of the cooling water flow direction with respect to the low temperature thermostat type response valve. The response temperature of the high temperature thermostat type response valve may be 90 to 95 ° C., and the response temperature of the low temperature thermostat type response valve may be 70 to 85 ° C. The valve area of the low temperature thermostat type response valve may be substantially equal to the valve area of the high temperature thermostat type response valve. The area of the orifice opened and closed by the electronic control valve may be substantially equal to the valve area of the low temperature thermostat type response valve. A plurality of electronic control valves may be connected in series with the low temperature thermostat type response valve.

  The main invention of the present application is an engine cooling device in which cooling water is circulated between the inside of an engine cooling jacket and a radiator, and a high temperature thermostat type response valve and a low temperature When the thermostat type response valve is connected in parallel and an electronic control valve is connected in series with the low temperature thermostat type response valve, the engine water temperature is controlled by the high temperature thermostat type response valve. Switching control is performed so that cooling water flows through the thermostat type response valve for low temperature by an electronic control valve.

  Therefore, according to such an engine cooling device, in the state where the engine water temperature is controlled by the high temperature thermostat type response valve, the switching control to the open state of the electronic control valve is performed, whereby the low temperature thermostat type The cooling water can be switched and flowed to the response valve, whereby the control of the cooling water in the high temperature control state can be switched in two stages.

  Therefore, when switching from low load operation to high load operation, switching the electronic control valve from the shut-off state to the open state causes the cooling water to flow mainly to the low temperature thermostat type response valve, depending on the engine operating state. Can respond to high-load operation quickly. Also, when the engine load and air conditioner load increase in midsummer, etc., and the heat load of the engine increases, both the high temperature thermostat type response valve and the low temperature thermostat type response valve open. The flow rate of the cooling water decreases and the cooling state is improved, and cavitation of the water pump that circulates the cooling water can be prevented.

  FIG. 1 and FIG. 2 show the overall configuration of the engine cooling device of the present embodiment. The cylinder head and cylinder block of the engine 10 and the radiator 11 are connected via main cooling pipes A and B. It is connected. The outlet side of the radiator 11 and the water jacket of the engine 10 are connected via return lines C, E, and F, and a water pump 12 is connected between the lines E and F. The radiator 11 is a heat exchanger for radiating the cooling water whose temperature has risen, and includes a cooling fan 13 on the back side.

  A bypass line D that bypasses the radiator 11 is connected to a connection part between the return lines C, E, and F, which connects the outlet side of the radiator 11 and the water jacket of the engine 10. At the same time, a high temperature thermostat type response valve 15 and a low temperature thermostat type response valve 16 are connected in parallel to each other at the connection portion between the pipes C and E. An electronic control valve 17 is further connected in series by a pipeline G upstream of the low temperature thermostat type response valve 16. The electronic control valve 17 is a control valve that is electronically controlled by the electronic control unit 18. The temperature of the cooling water at the outlet of the engine 10 is input to the electronic control unit 18 by the temperature sensor 19. Furthermore, the engine load state is input to the electronic control unit 18 via an accelerator sensor.

  Next, the configuration of the high temperature thermostat type response valve 15 and the low temperature thermostat type response valve 16 will be described with reference to FIGS. First, the high temperature thermostat type response valve 15 includes a metal frame 25, and a cylindrical case 26 is slidably fitted into a circular opening on the lower end side of the frame 25. The case 26 has a wax 27 enclosed therein and is attached so that the spool 28 closes the upper opening. The lower end of the rod 29 is inserted into the spool 28. The upper end of the rod 29 is received by the recess 32 of the bridge 31 of the flange 30 connected to the upper part of the frame 25.

  A support body 33 is attached to the upper end of the case 26 enclosing the wax 27 so as to protrude outward, and a valve body 34 is attached to the outer periphery of the support body 33. A compression coil spring 35 is interposed between the support 33 and the lower end portion of the frame 25. The compression coil spring 35 also serves as a support means for supporting the case 26 in an almost upright state in the frame 25. A rod 36 projects downward from the lower end of the case 26, and a valve body 38 is attached to the rod 36 so as to be pressed downward by a conical spring 37 interposed on the outer periphery of the rod 36. . The valve body 38 opens and closes an inlet 39 communicating with the bypass pipeline D.

  Next, the configuration of the low-temperature thermostat type response valve 16 will be described. The low-temperature thermostat type response valve 16 has substantially the same structure as the high-temperature thermostat type response valve 15, and the outer peripheral side is constituted by a frame 45. Has been. A case 46 is slidably attached through an opening on the lower end side of the frame 45, and the case 46 is filled with wax 47. The lower end of the rod 49 is inserted into the spool 48 that closes the opening at the upper end of the case 46 so as to enter the wax 47, and the upper end of the rod 49 presses the recess 52 of the bridge 51 of the flange 50. Yes.

  A support body 53 is attached to the upper end of the case 46 so as to extend outward in the radial direction, and a valve body 54 is attached to the outer periphery of the support body 53. The valve body 54 contacts the valve seat on the lower surface of the flange 50 to close the flow path. A compression coil spring 55 is attached to the outer periphery of the case 46, and the compression coil spring 55 urges the support 53 upward with respect to the frame 45.

  The pair of high-temperature thermostat type response valves 15 and low-temperature thermostat type response valves 16 are sandwiched and held at the joints between the inlet housing 60 and the outlet housing 61 via packings.

  Next, the configuration of the electronic control valve 17 provided on the inlet side above the low temperature thermostat type response valve 16 will be described. The electronic control valve 17 includes a cylindrical coil case 65, and a rod 66 is provided on the lower end side of the coil case 65 so as to protrude. The valve element 67 is loosely fitted to the rod 66 so that the valve element 67 is pressed by the rod 66. A compression coil spring 68 is interposed in the gap between the rod 66 and the valve body 67, and an O-ring 69 is interposed between the outer peripheral portion of the valve body 67 and the holding portion of the inlet housing 60. The valve body 67 comes into contact with the valve seat 70 of the inlet housing 60. The inlet housing 60 includes a partition wall 71 extending between the pair of thermostat type response valves 15 and 16, and a root portion of the partition wall 71 is the valve seat 70. A magnet 72 is housed in the coil case 65 together with the coil.

  In such a cooling device, the high temperature thermostat type response valve 15 responds at a temperature of 90 to 95 ° C., whereas the low temperature thermostat type response valve 16 is more preferably 70 to 85 ° C. Is designed to open at a temperature of 78-85 ° C. The high temperature thermostat type response valve 15, the low temperature thermostat type response valve 16, and the electronic control valve 17 all have a valve seat diameter of 34 mm and a lift of 3 mm. Are equal to each other.

  Next, the cooling operation by the engine cooling apparatus according to the above configuration will be described. First, the outline of the cooling operation of this cooling device will be described with reference to FIGS. During normal steady operation, the cooling water discharged from the engine 10 flows into the radiator 11 through the main cooling pipes A and B, and is cooled by heat exchange in the radiator 11 and the cooled cooling water. Is returned from the high temperature thermostat type response valve 15 and / or the low temperature thermostat type response valve 16 to the water jacket of the engine 10 through the pipe E, the water pump 12 and the pipe F. Since the water pump 12 is driven by the output of the engine 10 (see FIG. 2), the cooling water circulates between the engine 10 and the radiator 11 through the cooling pipe, whereby the engine 10 is cooled. .

  Here, since the pair of thermostat type response valves 15 and 16 are opened and closed in accordance with the temperature thereof, when the electronic control valve 17 is opened, the cooling is mainly performed through the low temperature thermostat type response valve 16 in a low temperature state. Water circulates. On the other hand, when the temperature gradually increases, both the low temperature thermostat type response valve 16 and the high temperature thermostat type response valve 15 are opened, so that the amount of the cooling water cooled and circulated by the radiator 11 becomes the temperature of the cooling water. It gradually increases as the value increases. Further, when the electronic control valve 17 is closed by the electronic control unit 18, the cooling water is shut off by the electronic control valve 17 even if the low temperature thermostat type response valve 16 is opened. Only the thermostat type response valve 15 for high temperature is recirculated without passing through the inside 16.

  Next, opening and closing operations of the high temperature thermostat type response valve 15 and the low temperature thermostat type response valve 16 will be described. Since the operating principles of these response valves 15 and 16 are the same, a description will be given by taking the high temperature thermostat type response valve 15 as an example. The wax 27 in the case 26 detects the temperature of the cooling water flowing around it, thereby changing its state. When the temperature of the surrounding cooling water is low, the wax 27 is solidified, and the spool 28 receives the rod 29 to the bottom thereof.

  On the other hand, when the wax 27 in the case 26 detects an increase in the temperature of the cooling water, the wax 27 is fluidized accordingly, and the spool 28 squeezes the rod 29 as shown in FIGS. And extrude upward. Therefore, the upper end of the rod 29 abuts against the recess 32 of the bridge 31, and the reaction force causes the case 26 including the spool 28 to move downward against the compression coil spring 35. Therefore, the valve body 34 is separated from the valve seat on the lower surface of the flange 30, and the valve is opened.

  When the temperature of the cooling water rises further, the wax 27 expands further, so that the spool 28 further pushes the rod 29 further. Accordingly, the case 26 further moves downward, and the valve body 38 that is elastically pressed by the conical spring 37 closes the inlet 39 and blocks the circulation of the cooling water by the bypass line D. The low-temperature thermostat type response valve 16 is the same as the high-temperature thermostat type response valve 15 except that the valve body 38 is not provided at the lower end portion, so that the bypass line D is not opened or closed.

  As described above, the high temperature thermostat type response valve 15 and the low temperature thermostat type response valve 16 open at a predetermined opening according to the temperature of the cooling water, so that the amount of the cooling water passing through the radiator 11 changes. In order to absorb such a change in the amount of cooling water, the bypass pipe D functions, and the high temperature thermostat type response valve 15 or the low temperature thermostat type response valve 16 in the cooling water pumped by the water pump 12. The limited cooling water will circulate from the bypass line D to the return line E.

  When the engine 10 is warmed up and the temperature of the cooling water is low, neither the high temperature thermostat type response valve 15 nor the low temperature thermostat type response valve 16 is opened. Therefore, the cooling water does not circulate in the radiator 11, and the entire amount of the cooling water pumped by the water pump 12 passes from the main cooling pipe A through the bypass pipe D to the high temperature thermostat type response valve 15 and the low temperature thermostat type response valve 16. From the inlet 39 of the outlet housing 61 provided with the above, it returns to the return line E, and then returns to the water jacket of the engine 10 through the water pump 12 and the return line F. Therefore, in this case, the engine 10 is warmed up quickly, and unnecessary cooling of the engine 10 during the warming up is avoided.

  Next, operations of the high temperature thermostat type response valve 15, the low temperature thermostat type response valve 16, and the electronic control valve 17 will be described. When the engine coolant is at a temperature higher than the sensitive temperature of the high temperature thermostat type response valve 15 and the engine is in a high temperature control state with a low load, as shown in FIG. 3, the high temperature thermostat type response valve is used. 15 and the low temperature thermostat type response valve 16 are opened, and the electronic control valve 17 is closed.

  Therefore, in this case, even if the low temperature thermostat type response valve 16 is opened, the cooling water is shut off by the electronic control valve 17, so that the total amount of the cooling water from the radiator 11 is only the high temperature thermostat type response valve 15. Flows to the water pump 12 side. At this time, a part of the cooling water is introduced from the bypass pipe D through the inlet 39 into the outlet housing 61 and circulated from the housing 61 to the water pump 12. Accordingly, by circulating the cooling water, the temperature of the cooling water of the engine 10 can be maintained at a relatively high temperature (for example, around 100 ° C.) when the engine 10 is under a low load, thereby reducing the friction of the engine 10. And fuel consumption is reduced. Further, the temperature of the cylinder of the engine 10 does not become excessively low, combustion is promoted, and harmful exhaust gas can be reduced.

  On the other hand, when the accelerator pedal is depressed to switch the engine from the low load state to the high load state, the electronic control unit 18 opens the electronic control valve 17 as shown in FIG. At this time, since the electronic control valve 17 is opened, the cooling water flows into the already opened low temperature thermostat type response valve 16, and the high temperature thermostat type response valve 15 is cooled by the radiator 11 at a low temperature. Closes when exposed to water. Therefore, the coolant temperature of the engine 10 is controlled by the low temperature thermostat type response valve 16 to maintain the low water temperature, and is controlled to the optimum water temperature (for example, 85 to 90 ° C.) corresponding to the high load operation of the engine 10.

  That is, when the electronic control valve 17 is opened in conjunction with an increase in the load of the engine 10, the cooling water starts to flow toward the low temperature thermostat type response valve 16. Since the low-temperature thermostat type response valve 16 is already open, the cooling water flows back to the low-temperature thermostat type response valve 16. Then, the cooling water cooled by the radiator 11 and the cooling water flowing through the bypass pipe D and flowing into the housing 61 are mixed in the outlet housing 61 shown in FIG. The opening amount of the low temperature thermostat type response valve 16 is adjusted according to the temperature sensing operation of the wax 47 according to the temperature of the mixed cooling water. Therefore, even when the electronic control valve 17 is fully opened, the opening amount of the thermostat type response valve 16 for low temperature is settled at a constant opening degree according to the temperature of the mixed cooling water. Further, when the load on the engine 10 further increases and the temperature of the cooling water rises, the high temperature thermostat type response valve 15 also starts to open gradually (see FIG. 5).

  The switching operation of the electronic control valve 17 by the electronic control device 18 as described above is shown in FIG. The electronic control unit 18 detects the temperature of the cooling water of the engine 10 by the temperature sensor 19 and determines whether or not this temperature is higher than a predetermined temperature. If the temperature is higher, the electronic control unit 18 further determines the load of the engine 10. The state, that is, the amount of depression of the accelerator pedal is read, and when the engine 10 is in a high load state and a high output, the coil in the coil case 65 of the electronic control valve 17 is energized for a short time, thereby The control valve 17 is opened. In addition, when the engine 10 is in a low load state again, the electronic control unit 18 applies a current having a reverse polarity to the coil in the coil case 65, thereby performing a valve closing operation.

  Even in the case where the temperature of the engine 10 tends to be high, such as in summer, the high temperature thermostat type response valve 15, the low temperature thermostat type response valve 16 and the electronic control valve 17 are opened as shown in FIG. As a result, the circulating water amount of the cooling water passing through the radiator 11 is increased, whereby the cooling performance can be improved.

  The electronic control valve 17 connected to the upstream side of the low temperature thermostat type response valve 16 is provided with a coil in a coil case 65, and the rod 66 is opposed to the compression coil spring 68 by the excitation of this coil and is shown in FIG. So that it moves upward. Then, the position of the rod 66 moved upward is held in the coil case 65 by the magnet 72, and energization of the coil is interrupted in a very short time. Therefore, the power consumption of the coil is extremely reduced, resulting in a low power consumption type electronic control valve.

  When the electronic control valve 17 is closed again, a pulse current having a reverse polarity of about 0.5 to 1 second is applied to the coil in the coil case 65, thereby overcoming the magnetic force of the magnet 72 and the rod 66. Extruded to the state shown in FIG. Instead of flowing a reverse polarity current, a part of the coil in the coil case 65 may be a reverse-winding coil, and a valve-closing operation may be performed by flowing a drive current of the same polarity to the reverse-winding coil. .

  Next, another embodiment will be described with reference to FIGS. This embodiment shows a structure in which a pair of electronic control valves 17 are arranged on the inlet side of the low temperature thermostat type response valve 16. The configuration of each electronic control valve 17 is the same as that of the electronic control valve 17 of the first embodiment, and a small pair of small electronic control valves 17 having small dimensions are arranged side by side.

  Here, FIG. 8 shows a state in which the high temperature thermostat type response valve 15 and the low temperature thermostat type response valve 16 are both opened and the pair of electronic control valves 17 are closed. On the other hand, FIG. 9 shows a state in which the high temperature thermostat type response valve 15 is closed, the low temperature side thermostat type response valve 16 is opened, and the electronic control valve 17 is opened. Note that the switching control of the pair of thermostat type response valves 15 and 16 and the electronic control valve 17 in this embodiment is basically the same as that in the first embodiment.

  According to such a configuration, since the pair of electronic control valves 17 can be controlled to be switched between the case where both the pair of electronic control valves 17 are opened and the case where only one is opened, the low temperature thermostat type response valve 16 is controlled by the pair of electronic control valves 17. It becomes possible to control the flow rate of the cooling water passing therethrough. Further, when opening and closing the pair of electronic control valves 17, it is possible to eliminate a shock when switching the cooling water or prevent cavitation of the water pump 12 by giving a time difference between the operations. become.

  Although the present invention has been described above with reference to the illustrated embodiments, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the technical idea of the invention included in the present application. For example, the opening and closing temperature, the value of the opening area, and the like of the high temperature thermostat type response valve 15 and the low temperature thermostat type response valve 16 in the above embodiment can be variously changed in accordance with the engine used.

  The present invention can be widely used for cooling devices for engines composed of various water-cooled internal combustion engines.

It is a piping diagram which shows the structure of the whole cooling device of an engine. It is a connection diagram which shows the structure of the whole engine cooling device. It is a principal part longitudinal cross-sectional view which shows the combination of the thermostat type response valve for high temperature, and the thermostat type response valve for low temperature. It is a longitudinal cross-sectional view similar to FIG. 3 in the state in which the electronic control valve was opened. It is the same longitudinal cross-sectional view as FIG. 3 in a high temperature state. It is a flowchart which shows the control action of switching of a pair of thermostat type response valve. It is a top view of an inlet housing provided with a pair of electronic control valves. It is the sectional view on the AA line in FIG. It is a longitudinal cross-sectional view similar to FIG. 8 in a state where a pair of electronic control valves is opened.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 11 Radiator 12 Water pump 13 Cooling fan 15 High temperature thermostat type response valve 16 Low temperature thermostat type response valve 17 Electronic control valve 18 Electronic control device 19 Temperature sensor 25 Frame 26 Case 27 Wax 28 Spool 29 Rod 30 Flange (Valve seat) )
31 bridge 32 recess 33 support body 34 valve body 35 compression coil spring 36 rod 37 conical spring 38 valve body 39 inlet 45 frame 46 case 47 wax 48 spool 49 rod 50 flange (valve seat)
51 Bridge 52 Concavity 53 Support Body 54 Valve Body 55 Compression Coil Spring 60 Inlet Housing 61 Outlet Housing 65 Coil Case 66 Rod 67 Valve Body 68 Compression Coil Spring 69 O-ring 70 Valve Seat 71 Bulkhead 72 Magnet

Claims (6)

In the engine cooling device in which the cooling water is circulated between the inside of the engine cooling jacket and the radiator,
A high temperature thermostat type response valve and a low temperature thermostat type response valve are connected in parallel to the cooling water circulation line, and an electronic control valve is connected in series with the low temperature thermostat type response valve,
The engine water temperature is controlled by the high temperature thermostat type response valve, and when the engine load increases, the electronic control valve performs switching control so that cooling water flows through the low temperature thermostat type response valve. Engine cooling system.   2. The engine cooling device according to claim 1, wherein the electronic control valve is connected upstream of the low temperature thermostat type response valve in a flow direction of the cooling water. 3.   The engine cooling according to claim 1, wherein a response temperature of the high temperature thermostat type response valve is 90 to 95 ° C, and a response temperature of the low temperature thermostat type response valve is 70 to 85 ° C. apparatus.   The engine cooling device according to claim 1, wherein a valve area of the low temperature thermostat type response valve is substantially equal to a valve area of the high temperature thermostat type response valve.   The engine cooling device according to claim 1, wherein an area of an orifice opened and closed by the electronic control valve is substantially equal to a valve area of the low temperature thermostat type response valve.   The engine cooling apparatus according to claim 1, wherein a plurality of electronic control valves are connected in series with the low temperature thermostat type response valve.

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