JP4384230B2 - Engine cooling system - Google Patents

Description

  The present invention relates to an engine cooling device, and more particularly, to an engine cooling device including a heater circulation channel that circulates coolant in a heater core and a bypass channel that bypasses the heater core.

  The engine cooling device includes a coolant circulation passage having a cooling jacket, a radiator, and a water pump provided in the engine, and cools the coolant that has become a high temperature by exchanging heat with the cooling jacket through the radiator, It is configured to return to the cooling jacket with a water pump. Further, the coolant circulation passage is usually provided with a bypass passage that returns the coolant to the cooling jacket without passing through the radiator during engine warm-up. Then, in order to allow the coolant to pass appropriately through the main circulation channel and the bypass channel passing through the radiator in the coolant circulation channel according to the coolant temperature, the upstream portion of the water pump in the coolant flow direction There is known one in which a thermostat device is arranged (see, for example, Patent Document 1).

  Also, as a cooling device for the engine, there is provided a heater circulation passage that circulates a part of the coolant in the cooling jacket through the heater core of the air conditioner for the passenger compartment, and a main circulation passage and a heater circulation passage that pass through these radiators. In order to control the flow of the coolant to and from the bypass channel, an on-off valve is provided in the bypass channel together with the thermostat device, and the on-off valve is opened when the liquid temperature of the coolant is high and closed when the temperature is low. It is known (see, for example, Patent Document 2).

  Further, in the configuration of Patent Document 2, when the coolant temperature is low, the main circulation passage that passes through the radiator is closed by the thermostat device, and the bypass passage is also closed by the on-off valve. If the engine speed is increased in this state, the coolant pressure will increase, which may cause malfunctions. If the coolant pressure exceeds the set pressure, the thermostat device will open. A bypass flow path that bypasses the heater circulation flow path at a position between the cooling jacket of the main circulation flow path and the radiator is provided, and the bypass flow path is lower than the set pressure of the thermostat device. There is known a control valve (differential pressure valve) that opens when the pressure exceeds the pressure (see, for example, Patent Document 3).

Further, as shown in FIG. 4, a main circulation passage 25 in which a cooling jacket 21 of an engine, a radiator 22, a thermostat device 23 having a differential pressure valve function and a water pump 24 are connected in this order, and a cooling core 21 to a heater core 26. A heater circulation passage 27 through which the coolant flows through the thermostat device 23 and a bypass passage 28 through which the coolant is bypassed from the cooling jacket 21 to the thermostat device 23, and the thermostat device 23 is set according to the liquid temperature of the coolant. The opening degree of the main circulation passage 25 is adjusted, the heater circulation passage 27 is always open, and the bypass passage 28 is the difference when the engine pressure is increased and the coolant pressure is increased during warm-up. An arrangement configured to open by a pressure valve function is also known. In FIG. 4, 23a is a temperature sensing part of the thermostat device 23, and 23b is a differential pressure valve mechanism part. The thermostat device 23 is a well-known device that is widely used, and a specific configuration example thereof is a configuration similar to the thermostat 12 in, for example, Patent Document 3 described above (a configuration in which the heater circulation channel 27 is always open). Is not displayed.) Is described.
Japanese Utility Model Publication No. 3-1207029 JP 2000-289444 A JP 2007-120281 A

  By the way, in the configuration described in FIG. 4 and the configuration described in Patent Document 3, when the engine speed increases and the coolant pressure increases during warm-up of the coolant at a low temperature, the difference in the thermostat device 23 occurs. Although the pressure valve function is activated and the coolant flows through both the heater circulation passage 27 and the bypass passage 28, it is possible to eliminate the possibility that the pressure of the coolant becomes excessive and causes trouble. Then, since the differential pressure valve mechanism portion 23b for opening and closing the bypass passage 28 is provided integrally with the thermostat device 23 disposed in the vicinity of the water pump 24, the bypass passage 28 is formed as shown in FIG. In addition to the piping 27a constituting the heater circulation passage 27, the piping 28a constituting the bypass passage 28 is connected to a coolant outlet provided in the cooling jacket 21 of the engine. It is configured by arranging to connect between the 29 and the thermostat device 23. For this reason, two pipes 27a and 28a are required, and there are problems that the number of parts and the number of work steps are increased, the cost is increased, the weight is increased, and the layout of the pipes is difficult. In addition, since the differential pressure valve mechanism 23b is located in the vicinity of the water pump 24, it is susceptible to pulsation from the water pump 24, so that there is a problem that its durability is lowered.

  In addition, in the configuration described in Patent Document 3, in addition to the heater circulation channel, a bypass channel that connects the thermostat device to the position between the cooling jacket and the radiator of the main circulation channel and the thermostat device is connected to the bypass circulation channel. Since the control valve (differential pressure valve) is arranged on the road, there are problems that the number of parts and the number of work steps are large, resulting in an increase in cost, weight, and difficulty in layout of piping.

  In view of the above-described conventional problems, the present invention can reduce the number of piping for circulating the coolant, reduce the cost and weight, facilitate the layout, and improve the durability of the differential pressure valve. An object is to provide an apparatus.

The engine cooling device of the present invention is cooled by a water pump in a coolant circulation passage having at least a heater circulation passage that circulates between a cooling jacket and a heater core provided in at least one of the cylinder head and cylinder block of the engine. In a cooling device for an engine that circulates a liquid, a cooling passage is provided to bypass the cooling jacket and a straight piping portion downstream of the heater core of the heater circulation passage so as to communicate with the cooling jacket. A differential pressure valve that opens when the liquid pressure on the cooling jacket side exceeds a predetermined value is provided at the liquid outlet.

  According to this configuration, the bypass flow path for bypassing the heater core is connected to the downstream portion of the heater core in the heater circulation flow path, and the flow path from the connection portion to the thermostat device disposed in the vicinity of the water pump is connected to the heater circulation flow. Since it is also used in the road, it is not necessary to arrange the pipe that forms the bypass flow path to the thermostat device, and it is only necessary to arrange a single pipe that forms the heater circulation flow path. The number of points and work man-hours can be reduced, the cost and weight can be reduced, and the piping layout can be facilitated. In addition, since the differential pressure valve that opens the bypass flow path when the liquid pressure on the cooling jacket side exceeds a predetermined value is provided at the cooling liquid outlet of the cooling jacket, the flow path length from the water pump to the differential pressure valve Becomes longer and the differential pressure valve is less affected by the pulsation of the water pump, and the durability of the differential pressure valve is improved. In addition, the heater circulation flow path and the bypass flow path are configured by a single pipe, so that the diameter of the heater circulation flow path can be increased, and the resistance of the heater circulation flow path is reduced, resulting in improved heater performance. Can be improved.

  In addition, when the bypass flow path is crossed and connected to the straight pipe section downstream of the heater core of the heater circulation flow path, even if the pressure pulsation from the water pump goes back to the heater circulation flow path, the bypass flow path The durability of the differential pressure valve can be further improved.

  According to the engine cooling apparatus of the present invention, the bypass flow path is connected to the heater circulation flow path, and the flow path from the connection portion to the thermostat device is also used as the heater circulation flow path, so that a single pipe It is possible to reduce the number of parts and work man-hours, reduce the cost and weight, simplify the piping layout, and cool the differential pressure valve that opens the bypass flow path. Since it is disposed at the coolant outlet of the jacket, the flow path length from the water pump to the differential pressure valve becomes longer, making the differential pressure valve less susceptible to the pulsation of the water pump and improving the durability of the differential pressure valve. .

  Hereinafter, an embodiment of a cooling device for an engine of the present invention will be described with reference to FIGS.

  In FIG. 1, the engine cooling device of the present embodiment includes a main circulation passage 5 in which an engine cooling jacket 1, a radiator 2, a thermostat device 3, and a water pump 4 are connected in this order, and a heater core 6 from the cooling jacket 1. A heater circulation passage 7 through which the coolant flows through the thermostat device 3, and a bypass passage 8 through which the coolant flows from the cooling jacket 1 by bypassing the heater core 6. These main circulation passage 5 and the heater circulation A coolant circulation channel 9 is constituted by the channel 7 and the bypass channel 8.

  The thermostat device 3 adjusts the opening degree of the main circulation flow path 5 according to the liquid temperature of the cooling liquid, passes the cooling liquid through the radiator 2 according to the liquid temperature, and keeps the liquid temperature of the cooling liquid in the cooling jacket 1 constant. Configured to maintain. Reference numeral 3a denotes a temperature sensing unit that senses the coolant temperature and adjusts the valve opening. Further, the heater circulation flow path 7 is configured to be always conductive.

  The bypass flow path 8 is configured to connect the cooling jacket 1 and the downstream portion of the heater core 6 of the heater circulation flow path 7 to bypass the heater core 6 from the cooling jacket 1 and to merge the coolant into the heater circulation flow path 7. Has been. Specifically, as shown in FIG. 2, the pipe 8 a forming the bypass flow path 8 is in contrast to the straight pipe section 7 b in the downstream portion of the heater core 6 of the pipe 7 a forming the heater circulation flow path 7. Connected to cross. Further, the connection portion 10 of the pipe 8a to the straight pipe portion 7b of the heater circulation flow path 7 is disposed at a position close to the coolant outlet portion to the bypass flow path 8 of the cooling jacket 1, and the bypass flow path 8 is It is formed relatively short.

  A differential pressure valve 11 is provided at the coolant outlet portion of the cooling jacket 1 to the bypass flow path 8 and opens when the liquid pressure of the cooling liquid on the cooling jacket 1 side exceeds a predetermined value to bypass the coolant. It is comprised so that it may flow toward 8. Specifically, as shown in FIG. 2, a differential pressure valve 11 is provided in a connection flange 12 that connects a pipe 8 a forming the bypass flow path 8 to a coolant outlet of the cooling jacket 1.

  In the above configuration, in the warm-up operation state immediately after engine startup, the liquid temperature of the cooling liquid in the cooling jacket 1 is low, so the main circulation path 5 is closed by the thermostat device 3 and the cooling liquid is not cooled by the radiator 2. . In this state, when the engine is operated at a low speed or a medium speed (up to 4000 rpm), the coolant passes through only the heater circulation channel 7 as shown by a thick solid line in FIG. As a result, the vehicle passes through the thermostat device 3 and circulates, so that the vehicle interior is quickly heated.

  Further, when the engine is operated at a high speed (4000 to 6000 rpm) in this warm-up operation state, the liquid pressure of the cooling liquid in the cooling jacket 1 is high as shown by a thick solid line in FIG. When the differential pressure valve 11 is opened, the coolant flows through the heater circulation channel 7 and an excessive amount of coolant flows through the bypass channel 8 with respect to the heater core 6. The coolant flows through the heater circulation flow path 7 at the connection portion 10 with the flow path 7, and flows toward the thermostat device 3 through the heater circulation flow path 7. Thus, since the coolant that has passed through the bypass channel 8 merges with the coolant that has passed through the heater circulation channel 7, the pipe 7 a that forms the heater circulation channel 7 in this embodiment is the heater circulation flow of the conventional example. A thing with a diameter larger than the piping of the road is applied. As a specific example, when the inner diameter of the bypass passage 8 is 8 mm and the inner diameter of the heater circulation passage 27 of the conventional example is 14.6 mm, the inner diameter of the heater circulation passage 7 of the present embodiment. Is set to 16.6 mm.

  Thereafter, when the liquid temperature of the cooling liquid in the cooling jacket 1 becomes high, the main circulation flow path 5 is opened by the thermostat device 3, and the cooling liquid in the cooling jacket 1 is shown by a thick solid line in FIG. Circulates mainly through the main circulation channel 5 and the heater circulation channel 7. In this state, since the liquid pressure of the cooling liquid in the cooling jacket 1 is not usually high, the differential pressure valve 11 is closed and the cooling liquid does not flow into the bypass flow path 8. Even in this state, when the flow rate of the coolant flowing through the main circulation channel 5 is greatly reduced in the thermostat device 3 and the flow rate of the coolant to the heater circulation channel 7 is reduced, the engine operates at high speed. When operated at the rotational speed, the liquid pressure of the cooling liquid in the cooling jacket 1 becomes high, the differential pressure valve 11 opens, and the cooling liquid flows through the bypass flow path 8.

  According to the engine cooling apparatus of the present embodiment described above, the bypass flow path 8 that bypasses the heater core 6 is connected to the downstream portion of the heater core 6 in the heater circulation flow path 7, and the vicinity of the water pump 4 from the connection portion 10. Since the heater circulation channel 7 also serves as the flow path to the thermostat device 3 disposed in the pipe 8, it is not necessary to provide the pipe 8a forming the bypass flow path 8 to the thermostat device 3, and the heater Since it is only necessary to arrange a single pipe 7a that forms the circulation flow path 7, the number of parts and work man-hours can be reduced, the cost and weight can be reduced, and the layout of the pipe can be facilitated. Can do.

  Further, since the differential pressure valve 11 that opens the bypass passage 8 when the hydraulic pressure on the cooling jacket 1 side becomes a predetermined value or more is disposed at the cooling liquid outlet portion of the cooling jacket 1, the differential pressure valve from the water pump 4 is provided. The length of the flow path up to 11 is increased, so that the differential pressure valve 11 is not easily affected by the pulsation of the water pump 4, and the durability of the differential pressure valve 11 is improved. In particular, since the pipe 8a forming the bypass flow path 8 is crossed and connected to the straight pipe portion 7b downstream of the heater core 6 in the heater circulation flow path 7, the pressure pulsation from the water pump 4 is reduced. Even if the heater circulation path 7 is traced back, it is difficult to enter the bypass flow path 8 and does not affect the differential pressure valve 11 disposed at the start end of the heater circulation path 7, thereby further enhancing the durability of the differential pressure valve 11. Can be improved.

  Further, since the bypass flow path 8 is also used as the heater circulation flow path 7 and is constituted by a single pipe 7a of the heater circulation flow path 7, if the diameter of the pipe 7a of the heater circulation flow path 7 is increased accordingly. As a result, since the flow resistance of the heater circulation flow path 7 becomes small when the coolant does not pass through the bypass flow path 8, an effect that the heater performance can be improved is also exhibited.

  In the engine cooling device of the present invention, the bypass flow path is connected to the heater circulation flow path, and the flow path from the connecting portion to the thermostat device is also used as the heater circulation flow path. It is possible to reduce the number of parts and work man-hours, reduce the cost and weight, simplify the piping layout, and install a differential pressure valve that opens the bypass channel on the cooling jacket. Since it is arranged at the coolant outlet, the flow path length from the water pump to the differential pressure valve becomes longer, making the differential pressure valve less susceptible to the pulsation of the water pump, and improving the durability of the differential pressure valve. It can be suitably used for an engine cooling device.

The block diagram of one Embodiment of the cooling device of the engine of this invention. The perspective view which shows the piping state of the heater circulation flow path and bypass flow path of the embodiment. Explanatory drawing of the circulation path of the cooling fluid in each operation state of an engine. The block diagram of the cooling device of the engine of a prior art example. The perspective view which shows the piping state of the heater circulation channel and bypass channel of the prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling jacket 3 Thermostat device 4 Water pump 6 Heater core 7 Heater circulation flow path 7b Straight piping part 8 Bypass flow path 9 Cooling liquid circulation flow path 10 Connection part 11 Differential pressure valve

Claims (1)

In an engine cooling apparatus for circulating a coolant with a water pump in a coolant circulation channel having at least a heater circulation channel that circulates between a cooling jacket and a heater core provided in at least one of an engine cylinder head and a cylinder block ,
A bypass passage is provided that crosses and communicates with the cooling jacket and the straight piping portion downstream of the heater core of the heater circulation passage, and the liquid on the cooling jacket side is provided at the coolant outlet portion to the bypass passage of the cooling jacket. An engine cooling apparatus comprising a differential pressure valve that opens when the pressure exceeds a predetermined value.

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