JP2017066929A - Cooling structure of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely dispose a bypass water jacket bypassing a cylinder block in compact.SOLUTION: In a combustion chamber peripheral water jacket (hereinafter, WJ) 112, cooling liquid supplied from a water pump 200 connected to a main cooling liquid inlet 110 disposed at one end side in a crank axial direction, flows toward the other end side in a crank axial direction, and in a head WJ116 communicated with the combustion chamber peripheral WJ at the other end side of the crank axial direction, the cooling water flows toward its one end side. An engine 100 includes a bypass WJ 113 for bypassing the combustion chamber peripheral WJ, and the cooling liquid is directly supplied from the water pump to a sub-cooling liquid inlet 111 disposed at its upstream end portion in the bypass WJ. A downstream end portion of the combustion chamber peripheral WJ is provided with a confluent portion 114 communicated with the downstream end portion of the bypass WJ.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling structure for an internal combustion engine.

  A liquid-cooled internal combustion engine (hereinafter referred to as an engine) generates a large amount of heat depending on its location, so it actively cools the cylinder head, which tends to be hotter than the cylinder block, while the cylinder block is too cold. It is necessary to manage the temperature so that it does not exist. By doing so, the engine can be maintained at an appropriate temperature, and the stability of combustion and the reliability of the engine structure can be improved.

  Specifically, the temperature of the engine structure is controlled by the flow rate of the coolant flowing through the water jacket provided inside the structure, the flow velocity, and the liquid temperature (temperature difference from the wall temperature). In order to actively cool the cylinder head, a large flow rate of coolant is required.

  However, the cooling structure of the engine generally employs a structure in which the coolant is connected to the water jacket in the cylinder block and the water jacket of the cylinder head. There is a risk of overcooling. In addition, for the cylinder block, it leads to an increase in pressure loss due to the flow of excess coolant.

  Therefore, in Patent Document 1, the cooling water discharged from the water pump is directed outward from the outer surface of the cylinder block to the cylinder head water jacket from the side portion on the exhaust side of the cylinder head without passing through the block water jacket. A cooling structure is disclosed in which a coolant supply pipe for introduction is provided and the cylinder head portion is effectively cooled by a coolant having a low temperature immediately after discharge from the water pump.

Japanese Utility Model Publication No. 62-52220

  However, according to the conventional technology, a coolant supply pipe is provided as a bypass on the outer surface of the structure, and there is a need to ensure the sealing performance of the connection portion between the coolant supply pipe and the cylinder head. In order to assemble the supply pipe to the cylinder head without interfering with the exhaust manifold, etc., a side extending portion is formed on the side of the exhaust side of the cylinder head, which increases the size (outside dimension) and weight of the structure. There is a problem.

  In view of such a point, the present invention has an object to provide a bypass water jacket that bypasses the cylinder block with a simple structure and more compactly.

  In order to solve the above problems, the present invention provides a bypass water jacket in a cylinder block water jacket (hereinafter referred to as a combustion chamber surrounding water jacket), and the downstream end of the bypass water jacket is connected to the downstream end of the combustion chamber surrounding water jacket. It is the structure connected with.

  Specifically, the present invention is directed to a cooling structure for an internal combustion engine, and has taken the following solutions.

  That is, the first invention is directed to a cooling structure for an internal combustion engine including a combustion chamber surrounding water jacket provided so as to surround the periphery of the combustion chamber of the cylinder block, and a head water jacket provided in the cylinder head. The water jacket around the combustion chamber is directed toward the other end side in the crankshaft direction by the coolant supplied by the coolant supply means connected to the main coolant inlet provided at one end side in the crankshaft direction of the internal combustion engine. The head water jacket communicates with the water jacket around the combustion chamber on the other end side in the crankshaft direction, and the coolant flows in the longitudinal direction toward one end side in the crankshaft direction. The internal combustion engine is a water jacket that bypasses the water jacket around the combustion chamber. The bypass water jacket is further supplied with a coolant directly from a coolant supply means to a sub-coolant inlet provided at an upstream end of the bypass water jacket, and a downstream end of the water jacket around the combustion chamber. Is provided with a junction that communicates with the downstream end of the bypass water jacket.

  According to this, the bypass water jacket is not connected to the cylinder head portion where the exhaust port, the intake port, the spark plug, the fuel injection device and the like are provided, but is communicated with the downstream end portion of the combustion chamber surrounding water jacket. Therefore, the above-mentioned part and device can be easily avoided. Therefore, the bypass water jacket can be communicated with a simple structure and compactly while bypassing the water jacket around the combustion chamber.

  According to a second aspect of the present invention, in the first aspect of the present invention, the water jacket spacer that partitions the combustion chamber peripheral water jacket into a combustion chamber side water jacket and an anti-combustion chamber side water jacket is disposed in the combustion chamber peripheral water jacket. The junction is in communication with the anti-combustion chamber side water jacket.

  According to this, the coolant that merges from the bypass water jacket also in the downstream portion of the combustion chamber peripheral water jacket by connecting the merge portion of the combustion chamber peripheral water jacket and the bypass water jacket to the anti-combustion chamber side water jacket. It is possible to prevent overcooling of the combustion chamber wall of the cylinder block.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the bypass water jacket is integrally formed below a lower end portion in the engine vertical direction of the combustion chamber surrounding water jacket in the cylinder block. .

  According to this, since the bypass water jacket is integrally formed below the combustion chamber surrounding water jacket in the cylinder block, it is not necessary to ensure the sealing performance of the connecting portion which is a problem when separately molded. it can.

  In a fourth aspect based on the third aspect, the bypass water jacket extends from the auxiliary coolant inlet in a substantially straight tube shape in the direction of the crankshaft of the cylinder block, and is provided below the lower end of the cylinder liner of the cylinder block. It is what has been.

  According to this, when the cylinder head and the cylinder block are fastened with bolts, the bypass water jacket is provided below the lower end portion of the cylinder liner of the cylinder block. Since the portion acts as a beam below the cylinder liner, deformation of the cylinder liner due to the tensile force of the bolt can be prevented.

  In a fifth aspect based on the first to fourth aspects, the main coolant inlet is provided with a valve structure capable of passing the coolant when the coolant is at a predetermined temperature or higher or at a predetermined pressure. The coolant inlet allows the coolant to flow regardless of the temperature and pressure of the coolant.

  According to this, for example, while the engine is warming up, the coolant flow in the cylinder block can be stopped to prevent overcooling of the cylinder block, while the combustion of the cylinder head whose temperature rises relatively fast The chamber wall can be prevented from excessively rising due to the coolant introduced from the bypass water jacket.

  According to the cooling structure for an internal combustion engine according to the present invention, the bypass water jacket that bypasses the cylinder block can be arranged with a simple structure and more compactly.

FIG. 1 is a schematic perspective view showing a cooling structure for an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a cross-sectional perspective view showing a joining portion of the combustion chamber surrounding water jacket and the bypass water jacket in the cylinder block constituting the internal combustion engine according to the embodiment of the present invention. FIG. 3 is a perspective view showing a water jacket spacer inserted into the combustion chamber peripheral water jacket according to the embodiment of the present invention. FIG. 4 is a perspective view showing a cooling structure of the cylinder block constituting the internal combustion engine according to one embodiment of the present invention. FIG. 5 is a cross-sectional perspective view taken along line VV in FIG. FIG. 6 is a sectional view in the direction perpendicular to the crankshaft showing the cooling structure of the cylinder block constituting the internal combustion engine according to the embodiment of the present invention. FIG. 7 is a schematic view showing an example of a coolant flow path and its control in the internal combustion engine cooling structure according to the embodiment of the present invention. FIG. 8 is a schematic view showing a modification of the coolant flow path and its control in the internal combustion engine cooling structure according to the embodiment of the present invention.

  Embodiments of the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its application.

(One embodiment)
A cooling structure of an internal combustion engine (hereinafter referred to as an engine) according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic perspective view showing an engine cooling structure according to this embodiment. The engine shown in FIG. 1 is, for example, a multi-cylinder in-line engine 100 mounted on a vehicle. As shown in FIG. 1, the engine 100 includes a cylinder block 120 that constitutes a cylinder portion, and a cylinder head 130 that is fixed on the cylinder block 120, for example, is bolted and constitutes a combustion chamber of each cylinder. A water pump 200 that forcibly circulates coolant for cooling the engine is disposed at one side end in the crankshaft direction parallel to the cylinder rows of the cylinder block 120. The water pump 200 is driven by transmitting the rotational force of a crankshaft (not shown) to the water pump drive shaft via a belt, and the coolant is introduced into the water pump 200 from the pump inlet 200a of the water pump 200, and the water pump 200 The coolant pumped by 200 is directly supplied to the main coolant inlet 110 provided on the relatively upper side of the cylinder block 120 and the sub-coolant inlet 111 provided on the relatively lower side of the cylinder block 120. be introduced.

  The main coolant inlet 110 is connected to a combustion chamber surrounding water jacket 112 that is a main flow path of the cylinder block 120, and the sub-coolant inlet 111 is connected to a bypass water jacket 113 that is a bypass flow path of the cylinder block 120. . At the downstream end of the bypass water jacket 113, a merging portion 114 communicating with the downstream end of the combustion chamber peripheral water jacket 112 is provided, and all of the coolant introduced into the bypass water jacket 113 is introduced into the combustion chamber peripheral water jacket 112. It has come to be. The coolant that has joined at the joining portion 114 is introduced into a headwater jacket inlet 115 that is provided downstream of the joining portion 114 in the coolant flow direction in the engine 100. The head water jacket 116 according to the present embodiment is formed so that the coolant that has passed through the combustion chamber peripheral water jacket 112 and the bypass water jacket 113 passes through the cylinder head 130 in the crankshaft direction. The head water jacket inlet 115 is the lower end in the vertical direction of the engine 100 in the head water jacket 116 and is connected to the downstream end of the combustion chamber surrounding water jacket 112, that is, the end on the side opposite to the water pump and the upper end in the vertical direction of the engine. It is provided to do.

  As described above, in the present embodiment, the combustion chamber peripheral water jacket 112 is configured such that the coolant supplied from the water pump 200 to the main coolant inlet 110 provided on one end side in the crankshaft direction of the cylinder block 120 receives the combustion chamber. After passing through the main coolant inlet 110 through the surrounding water jacket 112, it is immediately divided into the intake side and the exhaust side of the engine 100, and then flows into the other end side in the crankshaft direction. is there.

  FIG. 2 is a cross-sectional perspective view of a junction 114 between the combustion chamber surrounding water jacket 112 and the bypass water jacket 113 in the cylinder block 120 of the engine 100. As shown in FIG. 2, a combustion chamber peripheral water jacket 112 along the cylinder liner 118 is disposed immediately above the merge portion 114. Further, as a feature of the present embodiment, a water jacket spacer 300 shown in FIG. 3 is inserted into the combustion chamber surrounding water jacket 112.

  As shown in FIGS. 2 and 3, the water jacket spacer 300 according to the present embodiment is provided with a partition part 300 c that is a bent part above the center part in the vertical direction of the side surface. The upper part of the partition part 300c is a spacer upper part 300a provided with a gap with the cylinder liner 118, and the lower part of the partition part 300c is a spacer lower part 300b with substantially no gap between the cylinder liner 118. Thus, the combustion chamber peripheral water jacket 112 is divided into the combustion chamber side water jacket 112a by the partitioning portion 300c of the water jacket spacer 300 and the lower portion is the counter combustion chamber side water jacket opposite to the cylinder liner 118. It is partitioned into a jacket 112b. By providing the anti-combustion chamber side water jacket 112b, it is possible to prevent overcooling of the lower portion of the cylinder liner 118, which is less likely to be hot than the upper portion of the cylinder liner 118, and to reduce the vertical temperature difference of the cylinder liner 118. . The material of the water jacket spacer 300 according to the present embodiment is resin, but satisfies the function of partitioning the combustion chamber surrounding water jacket 112 into the combustion chamber side water jacket 112a and the anti-combustion chamber side water jacket 112b. If so, the material may be replaced with metal or the like. Further, the junction 114 between the combustion chamber peripheral water jacket 112 and the bypass water jacket 113 communicates mainly (substantially) with the anti-combustion chamber side water jacket 112b.

  In this manner, in the downstream portion of the combustion chamber surrounding water jacket 112, the coolant that has joined from the bypass water jacket 113 flows through the anti-combustion chamber side water jacket 112b, thereby further suppressing the overcooling of the cylinder liner 118. be able to.

  The height of the water jacket spacer 300 is set substantially equal to the depth of the combustion chamber surrounding water jacket 112. In this way, the combustion chamber side water jacket 112a and the anti-combustion chamber side water jacket 112b can be clearly defined.

  FIG. 4 is a perspective view of the cylinder block 120, and FIG. 5 is a cross-sectional perspective view taken along the line VV of FIG. As shown in FIG. 5, the bypass water jacket 113 according to the present embodiment is integrally formed with the cylinder block 120 below the lower end portion 112 </ b> A in the engine vertical direction of the combustion chamber surrounding water jacket 112 in the cylinder block 120. .

  If it does in this way, ensuring of the sealing performance of the connection part which becomes a subject when the bypass water jacket 112 is molded separately from the cylinder block 120 becomes unnecessary.

  Note that the disposition direction connecting the sub-cooling liquid inlet 111 and the merging portion 114 in the bypass water jacket 113 is formed in parallel or substantially parallel to the crankshaft direction. However, it is not always necessary to provide parallel or substantially parallel, and in order to reliably guide the air flowing into the bypass water jacket 113 to the outside of the engine 100, it is formed to be inclined to the auxiliary coolant inlet 111 side or the opposite side. Also good.

  In addition, a through-hole 113a is provided at the end of the bypass water jacket 113 opposite to the sub-cooling liquid inlet 111 shown in FIG. In the present embodiment, the cylinder block 120 is cast and the through portion 113a can be formed by removing a mold for integrally molding the bypass water jacket 113 together with the cylinder block 120. Therefore, when the engine is assembled, the through-hole 113a is sealed with a sealing material such as a cap material so that the coolant does not leak from the through-hole 113a.

  FIG. 6 shows a cross-sectional configuration in the direction perpendicular to the crankshaft 121 in the cylinder block 120 and is a view seen from the sub-cooling liquid inlet 111 side. As shown in FIG. 6, the bypass water jacket 113 according to this embodiment extends in a substantially straight tube shape in the crankshaft direction of the cylinder block 120. Further, the cylinder block 120 is provided substantially below the lower end portion of the cylinder liner 118, that is, at the boundary between the cylinder liner 118 and the crankcase 120b.

  In this way, when the cylinder head 130 and the cylinder block 120 are fastened together with a plurality of bolt holes shown in FIGS. A cylindrical portion extending and constituting the bypass water jacket 113 acts as a beam below the cylinder liner 118. As a result, deformation of the lower portion of the cylinder liner 118 due to the tensile force of each bolt can be prevented by the constituent members of the bypass water jacket 113 acting as a beam.

(Cooling liquid flow path and its control)
Below, the flow path and control of the coolant in the engine according to the present embodiment will be described with reference to FIG. FIG. 7 schematically shows the coolant flow path of the engine according to the present embodiment. As shown in FIG. 7, for example, the water pump 200 is activated simultaneously with the start of the engine, and the coolant is conducted to the combustion chamber surrounding water jacket 112 and the bypass water jacket 113 provided in the cylinder block 120. These coolants merge at a junction 114 between the combustion chamber peripheral water jacket 112 and the bypass water jacket 113 and are conducted to a head water jacket 116 provided in the cylinder head 130. The cooling fluid discharged from the head water jacket 116 is cooled by taking heat from the engine 100 inside the engine 100 and is re-introduced into the water pump 200 by the heat exchange with the outside air by the radiator 350. Note that the radiator 350 may be provided with a bypass flow path that bypasses the radiator 350 when the temperature of the coolant does not reach a predetermined temperature.

  Here, the ratio of the coolant that conducts between the combustion chamber peripheral water jacket 112 and the bypass water jacket 113 may be appropriately set according to the characteristics of the engine, and is not particularly limited. As an example, the conduction amount of the coolant in the combustion chamber surrounding water jacket 112 is about 60% to 70%, and the conduction amount of the coolant in the bypass water jacket 113 is about 40% to 30%.

(Cooling liquid flow path and one variation of its control)
FIG. 8 shows a modification of the coolant flow path and its control. As shown in FIG. 8, the main coolant inlet 110 may be provided with a valve (valve structure) 120c that allows the coolant to pass when the coolant is at a predetermined temperature or higher or at a predetermined pressure or higher. In contrast, the auxiliary coolant inlet 111 allows the coolant to flow regardless of the temperature and pressure of the coolant.

  In this way, the flow of the coolant in the combustion chamber surrounding water jacket 112, that is, the cylinder block 120, can be stopped during the warm-up process such as immediately after the engine is started. As a result, overcooling of the cylinder block 120 can be prevented, while the head water jacket 116 having a relatively high temperature rise, that is, the combustion chamber wall in the cylinder head 130 is cooled by the coolant flowing in from the bypass water jacket 113. An excessive increase in the combustion chamber wall temperature can be prevented.

  The cooling structure for an internal combustion engine (engine) according to the present invention can be applied to applications that require a bypass water jacket that bypasses the cylinder block.

100 engine (internal combustion engine)
110 Main coolant inlet 111 Sub-coolant inlet 112 Combustion chamber surrounding water jacket 112A Lower end portion 112a of combustion chamber surrounding water jacket 112a Combustion chamber side water jacket 112b Anti-combustion chamber side water jacket 113 Bypass water jacket 113a Through portion 114 Merge portion 115 Head Water jacket inlet 116 Head water jacket 117 Head water jacket outlet 118 Cylinder liner 120 Cylinder block 120a Head bolt hole 120b Crankcase 120c Valve (valve structure)
121 Crankshaft 200 Water pump (coolant supply means)
200a Pump inlet 300 Water jacket spacer 300a Spacer upper part 300b Spacer lower part 300c Partition part

Claims (5)

A cooling structure for an internal combustion engine, comprising a combustion chamber surrounding water jacket provided so as to surround the combustion chamber of the cylinder block, and a head water jacket provided in the cylinder head,
The water jacket around the combustion chamber has a coolant supplied by a coolant supply means connected to a main coolant inlet provided at one end in the crankshaft direction of the internal combustion engine toward the other end in the crankshaft direction. Is a vertical flow type water jacket
The head water jacket is a longitudinal water jacket that communicates with the combustion chamber surrounding water jacket on the other end side in the crankshaft direction and in which coolant flows toward the one end side in the crankshaft direction.
The internal combustion engine further includes a bypass water jacket for the coolant to bypass the combustion chamber surrounding water jacket,
The bypass water jacket is directly supplied with the coolant from the coolant supply means to the sub-coolant inlet provided at the upstream end of the bypass water jacket,
A cooling structure for an internal combustion engine, characterized in that a merging portion communicating with the downstream end portion of the bypass water jacket is provided at a downstream end portion of the combustion chamber surrounding water jacket. The combustion chamber peripheral water jacket is provided with a water jacket spacer that partitions the combustion chamber peripheral water jacket into a combustion chamber side water jacket and an anti-combustion chamber side water jacket,
The cooling structure for an internal combustion engine according to claim 1, wherein the merging portion communicates with the anti-combustion chamber side water jacket.   3. The internal combustion engine according to claim 1, wherein the bypass water jacket is integrally formed below a lower end portion in the engine vertical direction of the combustion chamber surrounding water jacket in the cylinder block. 4. Cooling structure.   The bypass water jacket extends in a substantially straight tube shape from the auxiliary coolant inlet in the crankshaft direction of the cylinder block, and is provided below a lower end portion of a cylinder liner of the cylinder block. Item 4. A cooling structure for an internal combustion engine according to Item 3. The main coolant inlet is provided with a valve structure capable of passing the coolant when the coolant is at a predetermined temperature or higher or a predetermined pressure or higher,
The cooling structure for an internal combustion engine according to any one of claims 1 to 4, wherein the auxiliary coolant inlet allows the coolant to flow regardless of the temperature and pressure of the coolant.

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