JP2011094523A - Cooling water passage structure in cylinder head of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling water passage structure in the cylinder head of an internal combustion engine, efficiently cooling the vicinity of a combustion chamber. <P>SOLUTION: A first cooling water passage 21 is formed inside of the side of the exhaust port 13 of the cylinder head 3, and also an exhaust-side second cooling water passage 32 is formed in a position closer to the combustion chamber 11 than the first cooling water passage 21 inside the cylinder head 3. The first cooling water passage 21 is made to communicate with the exhaust-side second cooling water passage 32 through a communication passage 41, and cooling water is made to flow from the side of the first cooling water passage 21 to the side of the exhaust-side second cooling water passage 32. The communication passage 41 is formed to be narrower than the first cooling water passage 21 and exhaust-side second cooling water passage 32, and also the axis 41X of the communication passage is arranged to be directed to the vicinity of the center of the combustion chamber 11. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a cooling water passage structure in a cylinder head of an internal combustion engine suitable for a diesel engine, and relates to a technique for efficiently cooling the cylinder head.

  In a diesel engine, the intake and exhaust valves are arranged in an almost upright state due to the shape of the combustion chamber for realizing a high compression ratio. Therefore, the fuel injection valve is arranged to face the vicinity of the center of the combustion chamber. In the case of the direct injection type, the members are densely packed around the fuel injection valve of the cylinder head, and the cooling water passage space is greatly restricted. On the other hand, in the direct injection type diesel engine, the heat receiving condition of the cylinder head becomes severer in the vicinity of the combustion chamber due to the combustion mode. Therefore, it is necessary to actively cool the vicinity of the combustion chamber by forming a cooling water passage inside the cylinder head.

  In the engine having such a member arrangement, in order to obtain high cooling performance around the combustion injection valve, the engine is directed from the side surface of the cylinder head to the fuel injection valve through the valve seats of the intake valve and the exhaust valve. A cooling water passage is formed, and the base end side of the cooling water passage is communicated with the cooling water passage on the cylinder block side, and the tip end side thereof is communicated with the cooling water passage on the cylinder head side. An invention has been proposed in which low-temperature cooling water supplied from is directly led to the periphery of a combustion injection valve (see Patent Document 1).

  Also, in the cooling water passage structure of the cylinder head in a multi-cylinder gasoline engine, in order to efficiently cool the parts having the most severe heat receiving conditions such as the periphery of the combustion chamber and the exhaust port, the cooling water is perpendicular to the cylinder arrangement direction for each cylinder. A first cooling water passage that flows in the (lateral direction), and a second cooling water passage that is connected to the first cooling water passage through the throttle passage, and guides the cooling water flowing from the throttle passage to the camshaft side (upward) along the exhaust port. An invention in which a water jacket is configured with a cooling water passage has been proposed (see Patent Document 2).

JP 2000-130162 A JP 2008-190497 A

  However, in the invention of Patent Document 1, in addition to a plurality of cooling water connection passages for circulating cooling water from the cooling water passage on the cylinder block side to the cooling water passage on the cylinder head side, a cooling water conduction path is further formed. The amount of cooling water flowing through the cooling water passage is small, and the cooling effect in the vicinity of the combustion chamber is low. The invention of Patent Document 1 is applied to a two-valve engine provided with one intake valve and one exhaust valve for each cylinder. However, when applied to a four-valve engine, the cooling water passage is provided. Since it becomes thin and a pressure loss becomes large, a cooling effect falls.

  On the other hand, in the invention of Patent Document 2, the first cooling water passage can be arranged around the combustion chamber. However, since there is an ignition plug (in the direct injection diesel engine, there is a fuel injection valve) One cooling water passage cannot be disposed in the center of the combustion chamber, and effective cooling is not performed in the vicinity of the combustion chamber having the strictest heat receiving conditions. The throttle passage functions to increase the flow rate in the lateral direction of the cylinder head, but does not actively cool the vicinity of the combustion chamber. Further, since the jet flow from the throttle passage flows along the exhaust port in the second cooling water passage, heat transfer by the jet flow is not effectively used and the cooling effect is low.

  The present invention has been devised to solve such problems imposed on the prior art, and a main object thereof is a cylinder head of an internal combustion engine capable of efficiently cooling the vicinity of the combustion chamber. An internal cooling water passage structure is provided.

  In order to solve such a problem, a cooling water passage structure in the cylinder head of the internal combustion engine (E) according to the first invention includes a first cooling water passage (21) formed inside the cylinder head (3). A second cooling water passage (exhaust-side second cooling water passage 32) formed closer to the combustion chamber (11) than the first cooling water passage (21) inside the cylinder head (3), The 1st cooling water channel | path (21) and the 2nd cooling water channel | path (32) are connected, and the communicating channel | path (41) which distribute | circulates cooling water from the 1st cooling water channel | path (21) side to the 2nd cooling water channel | path (32) side The communication passage (41) is narrower than the first cooling water passage (21) and the second cooling water passage (32), and its axis (41X) is directed to the combustion chamber (11). It is formed.

  According to this invention, the cooling water flowing through the first cooling water passage flows into the second cooling water passage as a jet directed to the combustion chamber by passing through the communication passage. Since the second cooling water passage is formed at a position close to the combustion chamber, the vicinity of the combustion chamber having a large heat reception is efficiently cooled with a high heat transfer rate by the principle of collision jet cooling.

  Further, according to the second invention, in the cooling water passage structure in the cylinder head of the internal combustion engine (E) according to the first invention, the axis (41X) of the communication passage is directed near the central portion of the combustion chamber (11). It is characterized by.

  According to the present invention, the cooling effect of the entire cylinder head can be enhanced by cooling the vicinity of the central portion of the combustion chamber having a large heat reception.

  Moreover, 3rd invention is the cooling water channel | path structure in the cylinder head of the internal combustion engine (E) based on 1st or 2nd invention, and the 2nd cooling water channel | path (32) ejected from the communicating path (41). It has a collision surface (32w) facing the jet of cooling water.

  According to the present invention, the jet flow from the communication path collides with the collision surface and is greatly disturbed, and the heat transfer coefficient is increased even if the amount of cooling water is the same. Therefore, the vicinity of the combustion chamber can be cooled more efficiently than when the jet collides with the wall surface of the second cooling water passage at a small angle.

  According to a fourth aspect of the present invention, in the cylinder head cooling water passage structure of the internal combustion engine (E) according to the first to third aspects of the invention, the internal combustion engine (E) includes a plurality of cylinders (cylinders 4). A plurality of passages (41) are formed for each cylinder (4), and at least one communication passage (41a) communicating with the upstream side of the first cooling water passage (21) is located downstream of the first cooling water passage (21). It is characterized by being narrower than at least one communication path (41b, 41c, or 41d) communicating with.

  The water pressure and cooling water flow rate in the communication path become smaller toward the downstream side of the first cooling water path due to the flow path resistance. Therefore, according to the present invention, the flow rate of the cooling water in each communication passage is reduced by making the communication passage located upstream of the first cooling water passage thinner than the communication passage located downstream of the first cooling water passage. It is possible to equally cool the vicinity of the combustion chamber of each cylinder.

  Thus, according to the present invention, it is possible to provide a cooling water passage structure in a cylinder head of an internal combustion engine that can efficiently cool the vicinity of the combustion chamber.

It is principal part sectional drawing which passes along the combustion chamber center of the internal combustion engine which concerns on embodiment. It is II-II sectional drawing in FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is IV-IV sectional drawing in FIG. It is VV sectional drawing in FIG. It is a mimetic diagram of a cooling water structure of an internal-combustion engine concerning an embodiment. It is principal part sectional drawing which passes along the combustion chamber center of the internal combustion engine which concerns on a modified example.

  Hereinafter, a cylinder head cooling water passage structure according to the present invention will be described in detail with reference to an embodiment shown in the accompanying drawings. In the present embodiment, the present invention is applied to an in-line four-cylinder diesel engine (hereinafter simply referred to as engine E), and FIG. 1 shows a cross-section of the main part passing through the center of the combustion chamber 11 of engine E. . In the description, it is assumed that the vertical direction is determined with reference to the state where the engine E is arranged with the cylinder shaft 4X vertical.

  As shown in FIG. 1, the engine E is slidable on a cylinder block 1, a cylinder head 3 fastened to the top of the cylinder block 1 via a gasket 2, and a cylinder 4 formed inside the cylinder block 1. The crankshaft (not shown) is rotationally driven through the connecting rod 6 connected to the piston 5 by the reciprocating motion of the piston 5. The cylinder head 3 is provided with two intake valves 7 and two exhaust valves 8 for each cylinder 4. These intake and exhaust valves 7, 8 are provided above the cylinder head 3 and cranked. It is opened / closed via a camshaft and a rocker arm (not shown) connected to the shaft. A reentrant cavity 5b centered on the cylinder shaft 4X is recessed at the center of the top surface 5a of the piston 5 to form a combustion chamber 11, and the cylinder head 3 defining the upper surface of the combustion chamber 11 A fuel injection valve 9 is mounted on the cylinder shaft 4X so that the injection port faces the center of the combustion chamber 11. The cylinder head 3 has a glow plug 10 as an auxiliary heat source for assisting the self-ignition of the fuel at the time of cold start with respect to the fuel injection valve 9 in such a manner that the heat generating portion 10a on the tip side protrudes into the combustion chamber 11. It is attached diagonally.

  Although not shown in the figure, a low pressure pump is provided in the fuel tank of the engine E, the fuel pumped from the low pressure pump is supplied to the high pressure pump, and the fuel pumped from the high pressure pump is supplied to the common rail. The The high-pressure fuel accumulated in the common rail is supplied to the fuel injection valve 9, and the fuel injection valve 9 is driven to open by the engine ECU, whereby a predetermined amount of high-pressure fuel spray is injected into the combustion chamber 11 at a predetermined timing. Is done.

  As shown in FIG. 3, the cylinder head 3 is formed with an intake port 12 to which an intake manifold (not shown) is connected, and an exhaust port 13 to which an exhaust manifold (not shown) is connected. Valve seats 14 and 15 on which the intake valve 7 and the exhaust valve 8 are respectively seated are provided at the connection with the combustion chamber 11. The intake valve 7 and the exhaust valve 8 are arranged so that the valve stems 7a and 8a are parallel to the cylinder shaft 4X, and the lower end surfaces of the valve heads 7b and 8b are in contact with the lower surface 3a of the cylinder head 3 in the closed state. It becomes the same position. On the other hand, the top surface 5 a of the piston 5 is at the same position as the top surface of the cylinder block 1 at the compression top dead center. Therefore, the top surface 5a of the piston 5 formed in an annular shape so as to surround the combustion chamber 11 is a flat surface without forming a valve recess. Then, at the compression top dead center, a squish 16 substantially corresponding to the thickness of the gasket 2 is formed between the top surface 5 a of the piston 5 and the lower surface 3 a of the cylinder head 3.

  As shown in FIGS. 1, 3, and 4, a portion extending from the upper part to the central part on the exhaust port 13 side in the cylinder head 3 avoids the exhaust port 13 and the exhaust valve 8 and extends in the cylinder row direction. A cooling water passage 21 is formed. As shown in FIGS. 5 and 6, a second cooling water introduction passage 52 is connected to one end of the first cooling water passage 21 in the cylinder row direction, and is fed from the water pump 50 through the cooling water piping. The cooling water to be supplied flows into the first cooling water passage 21 through the first cooling water introduction passage 51 and the second cooling water introduction passage 52 formed in the cylinder block 1. FIG. 6 is a schematic view in which the cooling water passage formed inside the cylinder block 1 and the cylinder head 3 is extracted and disassembled, and the hatched portion is a cross section of the cooling water passage. It shows that there is.

  Further, as shown in FIGS. 1, 3 and 5, the portion extending from the lower part to the center part on the exhaust port 13 side in the cylinder head 3 is similarly extended in the cylinder row direction while avoiding the exhaust port 13 and the exhaust valve 8. An existing exhaust-side second cooling water passage 32 is formed, and in the portion extending from the lower part of the cylinder head 3 on the intake port 12 side to the center part, the intake port 12, the intake valve 7, and the glow plug 10 are avoided in the cylinder row direction. An extending intake side second cooling water passage 33 is formed. As shown in FIGS. 2 and 6, the exhaust side second cooling water passage 32 and the intake side second cooling water passage 33 communicate with each other via a central second cooling water passage 34 formed between the cylinders 4. . The exhaust-side second cooling water passage 32, the intake-side second cooling water passage 33, and the central second cooling water passage 34 constitute a second cooling water passage 31.

  As shown in FIG. 5, the exhaust-side second cooling water passage 32 includes a first inter-valve passage portion 32 a formed between the two exhaust valves 8 of each cylinder 4, and the adjacent intake valve 7 and exhaust valve 8. There are two second inter-valve passage portions 32b formed between them, and these three inter-valve passage portions 32a and 32b form a Y-shaped three-pronged branch portion. The two second inter-valve passage portions 32 b are curved so as to surround the exhaust port 13 side of the fuel injection valve 9.

  As shown in FIG. 1, the first cooling water passage 21 and the exhaust-side second cooling water passage 32 communicate with each other via a total of four communication passages 41 formed for each cylinder 4. Each communication passage 41 is opened in the upper surface 3 b of the cylinder head 3 and a drill 19 indicated by an imaginary line is inserted into the processing hole 18 reaching the first cooling water passage 21, and the drill 19 is placed near the center of the combustion chamber 11. It is drilled by being driven to rotate and penetrating through the wall between the first cooling water passage 21 and the exhaust side second cooling water passage 32. Thereby, the communication path 41 is formed such that the axis 41 </ b> X is directed near the center of the combustion chamber 11. Further, the cross section of the communication passage 41 is smaller than each cross sectional area (cross sectional area perpendicular to the water flow direction) of the first cooling water passage 21 and the exhaust side second cooling water passage 32. That is, the communication passage 41 is formed narrower than the first cooling water passage 21 and the exhaust side second cooling water passage 32. The processing hole 18 is closed by the plug 20 after the communication passage 41 is formed.

  The communication passage 41 is formed at a position corresponding to the connecting portion (curved center portion) of the second inter-valve passage portion 32b that is curved along the fuel injection valve 9, so that the exhaust passage side second cooling water passage 32 has A collision surface 32w is formed at the trifurcated branch portion so as to face the jet of cooling water ejected from the communication passage 41 and the cooling water collides substantially vertically.

In addition, as shown in FIG. 4, the communication passage 41 is formed with four (41a, 41b, 41c, 41d) in order from the upstream side of the first cooling water passage 21 to which the second cooling water introduction passage 52 is connected. The cross-sectional area is smaller toward the upstream side. That is, when the cross-sectional areas of the communication passages 41a, 41b, 41c, and 41d are respectively Aa, Ab, Ac, and Ad, the relationship of the following expression (1) is established.
Aa <Ab <Ac <Ad (1)
Here, since the communication path 41 is drilled, the diameters of the communication paths 41a to 41d can be easily formed in different sizes by changing the drill diameter.

  On the other hand, inside the cylinder block 1, as shown in FIGS. 1 and 6, a cylinder wall cooling water passage 53 is formed so as to surround the four cylinders 4. The second cooling water passage 31 and the cylinder wall cooling water passage 53 communicate with each other through a plurality of connection paths 54 formed around each cylinder 4 as shown in FIGS. 3, 5, and 6. is doing. The connection path 54 is configured by a hollow portion that opens to the lower surface 3 a of the cylinder head 3 and reaches the second cooling water passage 31 and a through hole formed in the gasket 2. The cylinder wall cooling water passage 53 communicates with the radiator and the water pump 50 through a thermostat (not shown).

  According to the cooling water passage structure configured as described above, as shown in FIG. 6, the cooling water fed by the water pump 50 is the first cooling water formed inside the cylinder block 1 and the cylinder head 3. The first cooling water passage 21 is supplied to one end (upstream side) of the first cooling water passage 21 through the introduction passage 51 and the second cooling water introduction passage 52, and flows through the first cooling water passage 21 to the other end side (downstream side). It flows into the exhaust side second cooling water passage 32 through the passage 41. At this time, since the communication passages 41a to 41d are formed narrower than the first cooling water passage 21 and the exhaust side second cooling water passage 32, the cooling water passing through the communication passage 41 becomes a jet and becomes the exhaust side first. 2 flows into the cooling water passage 32. Further, due to the flow resistance when flowing through the first cooling water passage 21 downstream, the water pressure in the communication passage 41 is higher on the upstream side (41a side), but the cross-sectional area of the communication passage 41 is upstream (41a side). Therefore, the amount of cooling water in each of the communication passages 41a to 41d is equal, and each cylinder 4 can be cooled uniformly.

  The cooling water that has been jetted by passing through the communication passage 41 is injected into the exhaust-side second cooling water passage 32 along the axis 41X of the communication passage 41 when referring to FIGS. It collides substantially perpendicularly to the collision surface 32w of the three-pronged branch portion substantially orthogonal to 41X, disturbs the flow, and flows to the first inter-valve passage portion 32a and the two second inter-valve passage portions 32b. As a result, the entire portion of the cylinder head 3 in the vicinity of the combustion chamber 11 receiving a large amount of heat is efficiently cooled with a high heat transfer rate by the principle of collision jet cooling, and the exhaust port 13 through which the heat of the high-temperature exhaust gas is transmitted. The peripheral part of the slab is also efficiently cooled by cooling water that circulates at high speed.

  Part of the cooling water that has passed through the inter-valve passage portions 32a and 32b flows into the cylinder wall cooling water passage 53 through the connection passage 54 that opens to the exhaust side second cooling water passage 32, and the other part. Then, after flowing into the intake side second cooling water passage 33 through the central second cooling water passage 34 and cooling the intake side portion of the cylinder head 3, a connection path 54 opened to the intake side second cooling water passage 33 is provided. And flows into the cylinder wall cooling water passage 53. And after cooling the cylinder block 1, a cooling water is discharged | emitted to the cooling water piping connected to a thermostat.

<Modified Example>
Next, a modified example of the above embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part which has the same member and the same function as the said embodiment, and only a different point from the said embodiment is demonstrated. As shown in the figure, in this modified embodiment, the communication passage 41 that communicates the first cooling water passage 21 and the exhaust side second cooling water passage 32 has its axis 41X substantially parallel to the cylinder axis 4X, and It is formed in the vicinity of the side end of the combustion chamber 11. In the present embodiment, the communication passage 41 is not drilled but formed simultaneously with the first cooling water passage 21 and the second cooling water passage 31 during casting by a core. The lower wall portion defining the exhaust side second cooling water passage 32 of the cylinder head 3 faces the jet of cooling water ejected from the communication passage 41, and becomes a collision surface 32w where the cooling water collides substantially vertically. ing.

  According to the cooling water passage structure thus configured, the cooling water flowing through the first cooling water passage 21 becomes a jet along the axis 41X when flowing through the communication passage 41, and the exhaust side second cooling water. It flows into the passage 32 and collides with the collision surface 32w substantially perpendicularly to disturb the flow. And since the collision surface 32w is arrange | positioned in the lower wall part of the cylinder head 3 which defines the combustion chamber 11, the combustion chamber 11 vicinity site | part with a large heat receiving in the cylinder head 3 has a high heat transfer rate by the principle of collision jet cooling. It is cooled efficiently. In addition, since the communication passage 41 is formed on the exhaust side, the portion near the combustion chamber 11 on the exhaust port 13 side that is susceptible to the heat of the exhaust gas in the cylinder head 3 is cooled by the jet, and the cylinder head 3 is efficiently cooled. Is done.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above embodiment, the coolant passage structure in the cylinder head according to the present invention is applied to an in-line four-cylinder direct injection diesel engine. The present invention can be applied to different types of internal combustion engines such as a single cylinder engine, a pre-combustion chamber type or vortex chamber type diesel engine, a gasoline engine, and an alcohol fuel engine. In the above embodiment, the first cooling water passage 21 is disposed on the exhaust port 13 side of the cylinder head 3, and the first cooling water passage 21 is communicated with the exhaust side second cooling water passage 32 by the communication passage 41. However, the first cooling water passage 21 may also be formed on the intake port 12 side, and the communication passage 41 may be formed so that the first cooling water passage 21 communicates with the intake side second cooling water passage 33. In the above embodiment, the four communication paths 41a to 41d have a smaller cross section toward the upstream side of the first cooling water path 21, but for example, one or two communication paths (41a or 41a and 41a The cross-sectional area of the communication path 41 may be different in different modes, such as a mode in which only 41b) has a smaller cross section than the downstream communication path (41c or 41d). In addition, the specific configuration and arrangement of each member and part can be appropriately changed as long as they do not depart from the spirit of the present invention.

3 Cylinder head 4 Cylinder
DESCRIPTION OF SYMBOLS 11 Combustion chamber 21 1st cooling water path 31 2nd cooling water path 32 Exhaust side 2nd cooling water path 32w Colliding surface 41a, 41b, 41c, 41d Communication path 41X Axis E Engine

Claims (4)

A cooling water passage structure in a cylinder head of an internal combustion engine,
A first cooling water passage formed inside the cylinder head;
A second cooling water passage formed in a position closer to the combustion chamber than the first cooling water passage inside the cylinder head;
A communication passage for communicating the first cooling water passage and the second cooling water passage, and for circulating the cooling water from the first cooling water passage side to the second cooling water passage side;
Have
Cylinder head cooling water passage for an internal combustion engine, wherein the communication passage is narrower than the first cooling water passage and the second cooling water passage, and its axis is directed to the combustion chamber. Construction.   2. The cooling water passage structure in the cylinder head of the internal combustion engine according to claim 1, wherein an axis of the communication passage is oriented near a central portion of the combustion chamber.   3. The cooling water passage in the cylinder head of the internal combustion engine according to claim 1, wherein the second cooling water passage has a collision surface facing a jet of cooling water ejected from the communication passage. 4. Construction. The internal combustion engine includes a plurality of cylinders, and a plurality of the communication paths are formed for each cylinder.
The at least one communication passage communicating with the upstream side of the first cooling water passage is narrower than the at least one communication passage communicating with the downstream side of the first cooling water passage. Item 4. The cooling water passage structure in the cylinder head of the internal combustion engine according to any one of Items 3 to 4.

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