JP6795377B2 - Heater device and engine - Google Patents

Description

The present invention relates to a heater device that suppresses a temperature drop of cooling water while the engine is stopped, and an engine provided with the heater device.

For example, as in Patent Document 1, for automobiles for cold regions where the minimum temperature is minus several tens of degrees Celsius, the purpose is to improve the startability of the engine by preventing an excessive temperature drop of the cooling water while the engine is stopped. A block heater is attached to the cylinder block (engine block) as one heater device. In the block heater of Patent Document 1, a heating element is arranged in a cooling water flow path formed in an engine block, and the heating element receives power from an external power source to generate heat, so that the temperature of the cooling water drops excessively. Is suppressed.

Japanese Unexamined Patent Publication No. 2004-257299

However, a block heater in which a heating element is arranged in a cooling water flow path in an engine block as in Patent Document 1 is often attached instead of a core plug. Therefore, the engine block needs to be specially processed to attach a block heater.

An object of the present invention is to provide a heater device that can be attached to an engine block that has not been specially processed to attach a block heater, and an engine equipped with the heater device.

The heater device that solves the above problems is a heater device applied to an engine in which a cooling water flow path through which cooling water flows is formed by an internal flow path inside the engine block and an external flow path outside the engine block. The engine block has a connected portion to which a flange for communicating the internal flow path and the external flow path is connected, and the heater device is a relay flow path that is a part of the external flow path. The heater case has a block heater attached to the heater case and receives power from an external power source to heat the cooling water of the relay flow path, and the heater case is connected to the connected portion. It has a first connecting portion which is a flange to be formed, and a second connecting portion to which a pipe forming a part of the external flow path is connected.

An engine that solves the above problems is an engine provided with a heater device, and the engine has an internal flow path inside the engine block and an external flow path outside the engine block as a cooling water flow path through which cooling water flows. The engine block has a connected portion to which a flange for communicating the internal flow path and the external flow path is connected, and the heater device is a relay flow path that is a part of the external flow path. The heater case has a block heater attached to the heater case and receives power from an external power source to heat the cooling water of the relay flow path, and the heater case is connected to the connected portion. It has a first connecting portion which is a flange, and a second connecting portion to which a pipe forming a part of the external flow path is connected.

The external piping constituting the external flow path is usually connected to the engine block by using a flange from the viewpoint of reliability against leakage of cooling water and efficiency of connection work to the engine block. The heater device having the above configuration has a flange connected to the connected portion formed in the engine block as the first connecting portion. Therefore, it can be attached to an engine block that has not been specially processed to attach a block heater.

In the engine, it is preferable that the relay flow path is located above the portion closer to the first connection portion or the portion closer to the second connection portion.
According to the above configuration, the cooling water heated by the block heater flows toward the first connection portion by natural convection when it is located higher than the portion closer to the first connection portion, and the portion closer to the second connection portion. When it is located so high, it flows toward the second connection by natural convection. Therefore, the retention of cooling water in the relay flow path can be suppressed.

The engine has a pump for pumping cooling water to the cooling water flow path, and the relay flow path is located above the portion closer to the second connection portion and is closer to the second connection portion. It is preferable that the portion is located downstream of the pump.

According to the above configuration, the flow direction of the cooling water heated by the block heater in natural convection is the same as the flow direction of the cooling water during the operation of the pump, and the cooling water flows by inertia after the pump is stopped. It is the same as the flow direction. Therefore, the cooling water heated by the block heater does not change its flow direction even if the flow due to inertia disappears. As a result, the flow in the cooling water flow path can be smoothly transferred from the flow due to inertia to the flow due to natural convection.

In the engine, the relay flow path is preferably located on the most upstream side of the external flow path with respect to the pump.
The stopped pump acts as a resistance to the cooling water flowing through the cooling water flow path. Therefore, when the relay flow path is located on the most downstream side of the external flow path with respect to the pump, that is, when the second connection portion is connected to the suction side of the pump, the cooling heated by the block heater is performed. Water may stay on the suction side of the pump. In this respect, according to the above configuration, since the relay flow path is located on the discharge side of the pump, the pump is less likely to act as a resistance against the natural convection of the cooling water accompanying the heating of the block heater. As a result, the flow range of the cooling water due to natural convection is expanded, so that the temperature drop of the cooling water can be suppressed more effectively.

The perspective view which shows typically the schematic structure of one Embodiment of the engine which includes a heater device. The figure which shows an example of the schematic structure of the cooling system schematically. The perspective view which shows the perspective structure of one Embodiment of a heater device. FIG. 5 is a cross-sectional view showing a cross-sectional structure of a connecting portion between the cylinder block and the first connecting portion. The perspective view which shows the perspective structure of an example of a block heater. The figure which shows an example of the flow of cooling water by natural convection schematically.

A heater device and an embodiment of an engine including the heater device will be described with reference to FIGS. 1 to 6.
As shown in FIG. 1, the engine 10 has an engine block 13 composed of a cylinder block 11 and a cylinder head 12. The engine 10 is an engine equipped with an EGR device (not shown) that returns a part of the exhaust gas as EGR (Exhaust Gas Recirculation) gas to the intake side. The engine 10 has a heater device 40 attached to the cylinder block 11 of the engine block 13. In the cooling system 20 (see FIG. 2) mounted on the engine 10, the heater device 40 heats the cooling water by receiving power from an external power source while the engine 10 is stopped, thereby causing an excessive temperature drop of the cooling water. suppress.

As shown in FIG. 2, in the cooling system 20, the cooling water flow path through which the cooling water flows is an internal flow path 21 arranged inside the engine block 13 and an external flow path arranged outside the engine block 13. It is composed of 22. The cooling system 20 has a pump 24 that pumps cooling water to the internal flow path 21. The pump 24 is a mechanical pump driven by the crankshaft of the engine 10 and is attached to the cylinder block 11.

The internal flow path 21 includes a block-side water jacket 25 and a head-side water jacket 26 located downstream of the block-side water jacket 25 with respect to the pump 24 and into which cooling water that has passed through the block-side water jacket 25 flows in. have. The block-side water jacket 25 is arranged around the cylinder formed in the cylinder block 11. The head-side water jacket 26 is arranged around the intake port and the exhaust port formed in the cylinder head 12. The pump 24 discharges cooling water to a flow path leading to the block-side water jacket 25.

In the external flow path 22, the first external flow path 31 communicating with the branch flow path 28 branching from the flow path connecting the pump 24 and the block side water jacket 25, and the cooling water that has passed through the head side water jacket 26 flow. It has two external flow paths 32. In FIG. 2, the thick solid line indicates the first external flow path 31, and the thick dotted line indicates the second external flow path 32.

In the first external flow path 31, the cooling water that has passed through the heater device 40 attached to the cylinder block 11, the EGR cooler 33 for cooling the EGR gas, and the radiator 34 for cooling the cooling water returns to the suction side of the pump 24. It is composed. As described above, in the cooling system 20, the heater device 40 and the block side water jacket 25 are connected in parallel to the pump 24, and the first external flow path 31 is discharged from the pump 24 to the block side. The cooling water before flowing into the water jacket 25 flows in.

In the second external flow path 32, the cooling water that has passed through the oil cooler 35 that cools the engine oil and the thermostat 36 that opens the valve when the temperature of the cooling water is equal to or higher than the valve opening temperature returns to the suction side of the pump 24. It is composed.

As shown in FIG. 3, the heater device 40 includes a heater case 42 having a relay flow path 41 forming a part of the first external flow path 31, and a block that heats cooling water by receiving power supply from an external power source. It is equipped with a heater 43.

The heater case 42 is manufactured, for example, by machining a cast base material. The heater case 42 has an inner peripheral surface 44a forming a relay flow path 41, and has a tubular portion 44 extending upward while curving so that the flow direction of the cooling water turns by about 90 °, and the tubular portion 44. On the other hand, it is integrally formed and has a mounting portion 45 to which the block heater 43 is mounted.

One end of the tubular portion 44 is a first connecting portion 47 which is a flange connected to the connected portion 15 of the cylinder block 11, and the other end of the tubular portion 44 is one of the first external flow paths 31. A second connection portion 48 into which a hose 52 (see FIG. 1), which is a pipe forming the portion, is inserted. As shown in FIG. 1, the hose 52 connects the heater device 40 and the EGR cooler 33, and forms a part of the flow path of the first external flow path 31 on the inner peripheral surface thereof. The EGR cooler 33 is, for example, a shell-and-tube heat exchanger, which includes a lower tank 33L having a cooling water inlet (not shown), an upper tank 33U having a cooling water outlet (not shown), and a lower tank 33L and an upper tank 33U. It has a core portion 33C sandwiched between the two. The lower tank 33L is located above the second connecting portion 48, and the hose 52 is arranged so as to be located above the portion closer to the lower tank 33L. In the core portion 33C, heat exchange is performed between the cooling water flowing from the lower tank 33L to the upper tank 33U and the EGR gas flowing inside the core portion 33C.

As shown in FIG. 4, the first connecting portion 47 is a flange connected to the connected portion 15 of the cylinder block 11. The connected portion 15 is a portion where a plurality of female threads are formed on a connecting surface flattened by machining. The first connection portion 47 is connected to the cylinder block 11 by aligning the first connection portion 47 with the connected portion 15 and then fastening the first connection portion 47 to the cylinder block 11 with a predetermined tightening torque using a bolt 50. Cylinder. The gap between the engine block 13 and the first connecting portion 47 is sealed with a gasket 51 which is a sealing member. The gap between the engine block 13 and the first connecting portion 47 is not limited to the gasket 51, and may be sealed with a sealing member such as an O-ring.

As shown in FIGS. 1 and 3, the second connection portion 48 and the hose 52 are connected to each other by inserting an elastic hose 52 into the second connection portion 48 and then connecting the insertion portion of the hose 52 with a hose band. By tightening the portion 48, the gap between the second connecting portion 48 and the hose 52 is sealed.

When such a heater device 40 is attached to the engine block 13, the relay flow path 41 is arranged so that the portion closer to the second connection portion 48 is located above the portion closer to the first connection portion 47. That is, a part of the cooling water pumped by the pump 24 toward the block side water jacket 25 to the internal flow path 21 flows into the relay flow path 41 from the branch flow path 28 through the first connection portion 47, and is connected to the second connection. It flows into the hose 52 from the relay flow path 41 through the section 48.

As shown in FIG. 3, the mounting portion 45 is integrally formed with the tubular portion 44. The mounting portion 45 has a storage chamber 55 having a communication port 53 that opens on the inner peripheral surface 44a of the tubular portion 44 and a storage port 54 that opens on the outer surface of the mounting portion 45. In FIG. 3, the accommodation chamber 55 is arranged so that the end portion on the communication port 53 side overlaps the relay flow path 41 from the front side of the paper surface.

As shown in FIG. 5, the block heater 43 is fitted in the storage port 54 of the mounting portion 45 to close the storage port 54, and is fixed to the closing portion 57 and housed in the storage chamber 55 of the mounting portion 45. It has a heating element 58 to be generated, and an electric wiring 59 connected to an external power source to supply the power of the external power source to the heating element 58. The heating element 58 receives power from an external power source to generate heat, and is composed of, for example, a nichrome wire. The block heater 43 is attached to the attachment portion 45 by inserting the tip end portion of the heating element 58 into the accommodation chamber 55 from the accommodation port 54 and then closing the accommodation port 54 with the closing portion 57. The block heater 43 attached to the attachment portion 45 is arranged at a position where the tip end portion of the heating element 58 faces the inner peripheral surface 44a of the tubular portion 44 through the communication port 53. Further, the gap between the closing portion 57 and the peripheral wall of the accommodating port 54 is sealed by a sealing member such as an O-ring.

As shown in FIG. 3, the heater case 42 is integrally formed with a fixing portion for fixing the heater device 40 to the engine block 13 in addition to the tubular portion 44 and the mounting portion 45 described above. .. For example, the mounting portion 45 is formed with a first fixing portion 61 that fixes the mounting portion 45 to the engine block 13 with bolts. By fixing the mounting portion 45 to the engine block 13 by the first fixing portion 61, vibration of the mounting portion 45 with respect to the first connecting portion 47 is suppressed. Further, in the tubular portion 44, a second fixing portion 63 for fixing the second connecting portion 48 to the engine block 13 by a bolt is formed in the vicinity of the second connecting portion 48. By fixing the second connecting portion 48 to the engine block 13 by the second fixing portion 63, the vibration of the second connecting portion 48 with respect to the first connecting portion 47 is suppressed. The first fixing portion 61 and the second fixing portion 63 are formed so as to correspond to the spare female screw formed on the engine block 13.

That is, the heater case 42 is fixed to the engine block 13 at each of the second connecting portion 48 and the mounting portion 45 in addition to the first connecting portion 47. As a result, vibration of the second connecting portion 48 and the mounting portion 45 with respect to the first connecting portion 47 is suppressed. As a result, the mechanical load on the heater case 42 due to the vibration, particularly the mechanical load on the first connection portion 47 can be reduced.

According to the heater device of the above embodiment and the engine provided with the heater device, the effects listed below can be obtained.
(1) The external piping connected to the engine block 13 is usually connected to the engine block 13 from the viewpoint of reliability against leakage of cooling water from the connection portion with the engine block 13 and efficiency of connection work to the engine block 13. A flange is used for the connection part of. Therefore, since the first connection portion 47 of the heater device 40 is composed of a flange connected to the connected portion 15, the heater device is also applied to the engine block 13 which has not been specially processed to attach the block heater 43. 40 can be attached. As a result, it is possible to change the specifications to an engine for cold regions even if the engine is not designed for cold regions, and it is possible to increase the versatility of the engine.

Further, during the operation of the block heater 43, it is possible to suppress a decrease in temperature of not only the cooling water in the relay flow path 41 but also the cooling water in the internal flow path 21 due to the natural convection of the cooling water and the heat conduction in the cooling water. .. Therefore, the heater device 40 can have the same performance as a block heater attached to the cylinder block and having a heating element arranged in the internal flow path 21.

(2) As shown in FIG. 6, the relay flow path 41 is located above the portion closer to the second connecting portion 48. Therefore, the cooling water heated by the block heater 43 flows out from the accommodating chamber 55 to the relay flow path 41 by natural convection, and then flows toward the second connection portion 48 located above the accommodating chamber 55. Then, new cooling water is supplied to the accommodation chamber 55 from the side of the first connection portion 47 located below the accommodation chamber 55. That is, by locating the portion closer to the second connection portion 48 toward the upper side, it is possible to prevent the cooling water heated by the block heater 43 from staying in the relay flow path 41. As a result, heat transfer by natural convection is promoted, so that the temperature drop of the cooling water can be effectively suppressed in the entire cooling water flow path.

(3) In the range from the heater device 40 to the EGR cooler 33 in the first external flow path 31, the downstream portion is configured to be located upward. As a result, the cooling water heated by the block heater 43 easily flows into the EGR cooler 33, so that the cooling water heated by the block heater 43 is further suppressed from staying in the relay flow path 41. As a result, the effect described in (2) above becomes more remarkable.

(4) The flow direction of the natural convection is the same as the flow direction of the cooling water during the operation of the pump 24, and is also the same as the flow direction of the cooling water flowing by inertia after the engine 10 is stopped. Therefore, the cooling water heated by the block heater 43 can smoothly shift to the flow by natural convection without changing the flow direction even if the flow due to inertia disappears.

(5) The stopped pump 24 acts as a resistance of the cooling water flowing through the cooling water flow path. Therefore, when the relay flow path 41 is located on the most downstream side of the first external flow path 31 with respect to the pump 24, that is, when the second connection portion 48 is connected to the suction side of the pump 24, The cooling water heated by the block heater 43 may stay on the suction side of the pump 24. In this respect, in the above-described configuration, in the relay flow path 41, the portion near the first connection portion 47 is located on the upstream side with respect to the pump 24, and the discharge of the pump 24 is performed at the end portion on the first connection portion 47 side. It communicates with the branch flow path 28 on the side. That is, the relay flow path 41 is located on the most upstream side of the pump 24 in the first external flow path 31. Therefore, when the cooling water heated by the block heater 43 flows through the cooling water flow path, the pump 24 is less likely to act as a resistance. As a result, the range in which the cooling water can flow is expanded by the natural convection accompanying the heating of the block heater 43, so that the temperature drop of the cooling water can be more effectively suppressed in the entire cooling water flow path.

(6) The heating element 58 of the block heater 43 is housed in a storage chamber 55 that communicates with the relay flow path 41 through the communication port 53. Therefore, the heating element 58 of the block heater 43 does not easily act as a resistance of the cooling water flowing through the relay flow path 41 during the operation of the engine 10. As a result, the pressure loss of the cooling water in the heater device 40 is reduced, so that the increase in the load of the pump 24 due to the mounting of the heater device 40 can be suppressed.

The above embodiment can be modified as appropriate and implemented as follows.
The heater device 40 may have a configuration in which the relay flow path 41 communicates with the internal flow path 21 by connecting the first connection portion 47 to the connected portion 15 of the engine block 13. Therefore, the heater device 40 may have a configuration in which the relay flow path 41 communicates with, for example, a flow path through which the cooling water that has passed through the block-side water jacket 25 flows, instead of the branch flow path 28. Further, the heater device 40 may have a configuration in which the second connecting portion 48 is connected to the suction side of the pump 24 so that the relay flow path 41 is located on the most downstream side of the first external flow path 31.

The relay flow path 41 may be located closer to the first connection portion 47 on the downstream side with respect to the pump 24.
In the heater device 40, the flow direction of the cooling water heated by the block heater 43 due to natural convection may be different from the flow direction of the cooling water by the pump 24. That is, for example, the relay flow path 41 may be configured so that the portion closer to the first connection portion 47 is located on the downstream side with respect to the pump 24 and the portion closer to the second connection portion 48 is located above. Good.

-The relay flow path 41 may be configured to be located above the portion closer to the first connection portion 47. In such a configuration, since the cooling water heated by the block heater 43 flows into the block side water jacket 25 by natural convection, the cooling water of the internal flow path 21 and the temperature drop of the engine block 13 are effectively suppressed. be able to.

The second connecting portion 48 may be formed of a flange.
-The heater case 42 is not limited to the one manufactured by machining a cast base material, and may be manufactured by joining pipes and joints by welding or the like. Further, the shape of the heater case 42 can be appropriately changed according to the piping around the connected portion 15 of the engine block 13.

-At least a part of the heating element 58 of the block heater 43 may be located in the relay flow path 41, and the shape thereof may be appropriately changed according to the shape of the accommodation chamber 55.
The engine block 13 may be a monoblock in which the cylinder block 11 and the cylinder head 12 are integrally formed.

10 ... engine, 11 ... cylinder block, 12 ... cylinder head, 13 ... engine block, 15 ... connected part, 20 ... cooling system, 21 ... internal flow path, 22 ... external flow path, 24 ... pump, 25 ... block side Water jacket, 26 ... Head side water jacket, 28 ... Branch flow path, 31 ... First external flow path, 32 ... Second external flow path, 33 ... EGR cooler, 33C ... Core part, 33L ... Lower tank, 33U ... Upper tank , 34 ... radiator, 35 ... oil cooler, 36 ... thermostat, 40 ... heater device, 41 ... relay flow path, 42 ... heater case, 43 ... block heater, 44 ... tubular part, 44a ... inner peripheral surface, 45 ... mounting Part, 47 ... 1st connection, 48 ... 2nd connection, 50 ... Bolt, 51 ... Gasket, 52 ... Hose, 53 ... Communication port, 54 ... Storage port, 55 ... Storage room, 57 ... Blocking part, 58 ... Heat generator, 59 ... electrical wiring, 61 ... first fixed portion, 63 ... second fixed portion.

Claims (2)

A heater device applied to an engine in which a cooling water flow path through which cooling water flows is formed by an internal flow path inside the engine block and an external flow path outside the engine block.
The engine block has a connected portion to which a flange for communicating the internal flow path and the external flow path is connected.
The heater device has a heater case having a relay flow path that is a part of the external flow path, and a block heater that is attached to the heater case and receives power supply from an external power source to heat cooling water. ,
The heater case is a first connection in which a tubular portion forming the relay flow path and a mounting portion to which the block heater is mounted are integrally formed, and is a flange connected to the connected portion. has a part at one end of the tubular portion, a second connecting portion pipe which forms part of the external passage is connected to the other end of the tubular portion, further, the mounting portion A heater device having a first fixing portion for fixing the engine block to the engine block and a second fixing portion integrally formed in the tubular portion for fixing the second connecting portion to the engine block. .. An engine equipped with a heater
The engine has an internal flow path inside the engine block and an external flow path outside the engine block as a cooling water flow path through which cooling water flows.
The engine block has a connected portion to which a flange for communicating the internal flow path and the external flow path is connected.
The heater device has a heater case having a relay flow path that is a part of the external flow path, and a block heater that is attached to the heater case and receives power supply from an external power source to heat cooling water. ,
The heater case is a first connection in which a tubular portion forming the relay flow path and a mounting portion to which the block heater is mounted are integrally formed, and is a flange connected to the connected portion. has a part at one end of the tubular portion, a second connecting portion pipe which forms part of the external passage is connected to the other end of the tubular portion, further, the mounting portion Has a first fixing portion for fixing the engine block to the engine block, and a second fixing portion integrally formed with the tubular portion for fixing the second connecting portion to the engine block.
The internal flow path includes a water jacket.
The relay flow path is an engine that communicates with the flow path through which the cooling water flowing into the water jacket or the cooling water flowing out from the water jacket flows by connecting the first connection portion to the connected portion. ..

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