JP6406157B2 - cylinder head - Google Patents

Description

  The present invention relates to a cylinder head applied to a four-valve engine or the like, and more particularly to a structure of a water jacket of the cylinder head.

  A water jacket is formed on the cylinder block and the cylinder head constituting the engine. Cooling water from a lower cylinder block (block water jacket) is supplied to the water jacket of the cylinder head.

  Further, as a cooling structure of the cylinder head, one provided with an upper water jacket and a lower water jacket is known (for example, see Patent Document 1).

JP 2003-184644 A

  By the way, in the cylinder head of a four-valve type engine, since the exhaust ports of the cylinders are particularly hot, it is required to cool the exhaust system including the exhaust ports effectively. Moreover, in the cylinder head in which the upper and lower water jackets are formed, it is necessary to ensure the flow rate of the cooling water to the upper water jacket.

  The present invention has been made in consideration of such circumstances, and in the cylinder head in which the upper water jacket and the lower water jacket are formed, while ensuring the amount of cooling water to the upper water jacket, between the exhaust ports, etc. An object of the present invention is to provide a structure capable of effectively cooling the exhaust system.

  The present invention relates to a cylinder head in which at least two intake ports and two exhaust ports are formed for each of a plurality of cylinders of an engine, and an ignition plug is provided. The cylinder head includes an upper water jacket and a lower side. A water jacket is formed.

The lower water jacket is formed between an exhaust side cooling water inlet into which cooling water from a cylinder block below the cylinder head flows, and the exhaust port of each cylinder, from the exhaust side cooling water inlet A cooling water passage between exhaust ports for flowing the cooling water flowing toward the ignition plug, a cooling water passage around the plug connected to the cooling water passage between the exhaust ports and for flowing cooling water around the ignition plug, and the plurality of the plurality of cooling water passages A longitudinal cooling water passage formed over the cylinders, in which the cooling water flows in the longitudinal direction of the cylinder head, and a cooling water outlet formed at a position above the longitudinal cooling water passage and between adjacent cylinders; A communication path that connects the cooling water outlet and the upper water jacket, and a position between adjacent cylinders so as to intersect the longitudinal cooling water path Is a lateral direction the cooling water passage through which cooling water flowing from below the cylinder block flows in the lateral direction of the cylinder head, and wherein the lateral direction the cooling water passage, the cooling water around the exhaust valve And a cooling water outlet side passage formed into a groove shape so that the bottom surface of the passage is lower than the bottom surface of the passage in the longitudinal direction of the cooling water passage. It is connected to the longitudinal cooling water passage, and the cross-sectional area between the cooling water passage around the plug and the cooling water outlet is larger than the cross-sectional area of the cooling water passage between the exhaust ports. It is said.

According to the present invention, the cooling water rising from the cylinder block (block water jacket) flows into the inter-exhaust port cooling water passage through the exhaust side cooling water inlet and flows into the inter-exhaust port cooling water passage. Thus, the cooling water flows through the cooling water passage between the exhaust ports, so that the space between the exhaust ports can be reliably cooled. At this time (when the cooling water flows into the cooling water passage between the exhaust ports), the cooling water flows upward, and the cooling water flowing into the cooling water passage around the plug from the cooling water passage between the exhaust ports also faces upward. It becomes. Here, in the present invention, since the passage cross-sectional area between the plug-around cooling water passage and the cooling water outlet is large and the pressure loss is small, the cooling water discharged from the plug-around cooling water passage (cooling of the upward flow) water) tends to flow into the longitudinal cooling water passages, Reya becomes easier pulled into the cooling water outlet (communication passage). As a result, most of the cooling water from the cooling water passage between the exhaust ports flows through the upper side of the longitudinal cooling water passage and flows into the upper water jacket through the cooling water outlet (communication passage).

  In this way, by flowing the cooling water through the cooling water passage between the exhaust ports, the space between the exhaust ports can be reliably cooled. In addition, by raising the cooling water from the cooling water passage between the exhaust ports to the upper water jacket as it is, a sufficient amount of cooling water to the upper water jacket can be secured.

  On the other hand, cooling water that has flowed from the lower cylinder block (block water jacket) through the short-side cooling water passage flows into the longitudinal cooling water passage that intersects the short-side cooling water passage. As described above, since the cooling water from the cooling water passage between the exhaust ports has already flowed above the passage, the cooling water flowing into the longitudinal cooling water passage from the short direction cooling water passage is below the passage. To flow to the side. That is, the cooling water flowing in the short direction cooling water passage flows on the side close to the combustion chamber, and the combustion chamber can be effectively cooled.

  As described above, according to the present invention, the space between the exhaust ports can be reliably cooled while the amount of cooling water to the upper water jacket is secured, and the combustion chamber can be effectively cooled.

  According to the present invention, in the cylinder head in which the upper water jacket and the lower water jacket are formed, the exhaust system between the exhaust ports and the like is effectively cooled while ensuring the amount of cooling water to the upper water jacket. Can do.

It is a schematic structure which shows an example of an engine. It is sectional drawing which shows an example of an engine. It is a perspective view which shows the structure of the water jacket of a cylinder block and a cylinder head. It is a figure which shows typically the principal part structure of the water jacket of the cylinder head of this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

-Engine-
First, an example of an engine (internal combustion engine) to which the present invention is applied will be described with reference to FIGS. 1 and 2.

  The engine 300 in this example includes a cylinder block 200, a cylinder head 100 provided on the upper portion of the cylinder block 200, and the like.

  The engine 300 is, for example, an in-line 4-cylinder gasoline engine (4-valve engine). The cylinder block 200 and the cylinder head 100 are fastened by a head bolt (not shown). A gasket 400 is sandwiched between the cylinder block 200 and the cylinder head 100. FIG. 2 shows only one of the four cylinders.

  In the following description, the cylinder arrangement direction is referred to as a longitudinal direction (X direction), and a direction perpendicular to the longitudinal direction is referred to as a short direction (Y direction).

  In the cylinder block 200, a plurality of (four) cylinder bores 301 are arranged in a line along the longitudinal direction. A piston 302 is accommodated in each cylinder bore 301 so as to be able to reciprocate. The piston 302 is connected to a crankshaft (not shown) via a connecting rod (not shown), and the reciprocating motion of the piston 302 is converted into rotation of the crankshaft by the connecting rod.

  A combustion chamber 300 a is formed between the piston 302 and the cylinder head 100 in the cylinder bore 301. The cylinder head 100 is provided with a pair (two) of intake ports 303 and exhaust ports 304 communicating with each combustion chamber 300a for each cylinder. The cylinder head 100 is also provided with two intake valves 305 that open and close each intake port 303 and two exhaust valves 306 that open and close the exhaust port 304. Further, a spark plug 307 is disposed on the cylinder head 100 so as to face the combustion chamber 300a. The cylinder head 100 is provided with an injector (not shown) for injecting fuel into the intake port 303 or the combustion chamber 300a.

  As shown in FIGS. 1 to 3, the cylinder block 200 is provided with a block water jacket 201. The block water jacket 201 is formed so as to surround the plurality of cylinder bores 301.

  Cooling water from the water pump 500 is supplied to the block water jacket 201. A part of the cooling water supplied to the block water jacket 201 is supplied to the oil cooler.

  The cooling water supplied to the block water jacket 201 is supplied to the lower water jacket 20 of the cylinder head 100 described later through an intake side gasket hole 401 and an exhaust side gasket hole 402 formed in the gasket 400.

  Hereinafter, the intake side gasket hole 401 is also referred to as “intake side cooling water inlet 401”. The exhaust side gasket hole 402 is also referred to as “exhaust side cooling water inlet 402”. The intake-side cooling water inlet 401 is disposed in the vicinity of the intake valve 305 (arranged at eight locations), and the exhaust-side cooling water inlet 402 is disposed between the exhaust ports 304 of each cylinder C (arranged at four locations). (See FIG. 3 and FIG. 4).

-Cylinder head-
Next, an embodiment of a cylinder head will be described with reference to FIGS.

  As described above, the cylinder head 100 is disposed on the upper portion of the cylinder block 200.

  The cylinder head 100 is formed with an upper water jacket 10 and a lower water jacket 20. The lower water jacket 20 communicates with the block water jacket 201 through a communication passage 30 described later. In FIG. 2, the upper water jacket 10 and the lower water jacket 20 are not shown.

  The upper water jacket 10 includes an intake side cooling water inlet passage 11 and an exhaust side cooling water outlet passage 12 that extend in the longitudinal direction (X direction) of the cylinder head 100, and these intake side cooling water inlet passage 11 and exhaust side cooling water outlet passage. And an upper cooling passage 13 connected between the two. Cooling water from the lower water jacket 20 flows into the intake-side cooling water inlet passage 11 through a communication passage 30 described later. The cooling water that has flowed into the intake-side cooling water inlet passage 11 flows through the upper cooling passage 13 and flows into the exhaust-side cooling water outlet passage 12. And the cooling water which passed the upper water jacket 10 heads for a radiator.

  The lower water jacket 20 includes the above-described exhaust-side cooling water inlet 402, the inter-exhaust-port cooling water passage 21, the plug-around cooling water passage 22, the longitudinal cooling water passage 23, the short-side cooling water passage 24, and the like. ing.

  The cooling water passage 21 between the exhaust ports is disposed between the pair of exhaust ports 304 of each cylinder C. A cooling water passage 21 between the exhaust ports is provided for each cylinder C. The inter-exhaust-port cooling water passage 21 extends along the short direction (Y direction) of the cylinder head 100, and one end thereof communicates with the exhaust-side cooling water inlet 402. A cooling water passage 22 around the plug is connected to the other end of each cooling water passage 21 between the exhaust ports. The cooling water passage 21 between the exhaust ports and the cooling water passage 22 around the plug communicate with each other.

  The plug-around cooling water passage 22 is provided for each spark plug 307. The plug-around cooling water passage 22 is formed in a shape (branch shape) surrounding the spark plug 307. The plug-around cooling water passage 22 communicates with a longitudinal cooling water passage 23 described later. Since the peripheral portion of the spark plug 307 is directly affected by ignition and combustion, the cooling capacity of the plug-around cooling water passage 22 is increased (the cross-sectional area of the flow passage is increased). Further, the upper surface (passage height) of the cooling water passage 22 around the plug is made higher than the upper surface (passage height) of the inter-exhaust-port cooling water passage 21.

  The longitudinal coolant passage 23 is disposed on the intake side in the cylinder head 100. The longitudinal direction cooling water passage 23 is a path for core strength, and is formed throughout the plurality of cylinders. The longitudinal cooling water passage 23 extends along the longitudinal direction (X direction) of the cylinder head 100 so that the cooling water flows in the longitudinal direction. The longitudinal cooling water passage 23 is a cooling water passage having a flat bottom surface.

  In the longitudinal cooling water passage 23, a cooling water outlet 23 a is formed at a position that is intermediate between adjacent cylinders C and at a position that is an upper portion of the longitudinal cooling water passage 23. The cooling water outlets 23 a are arranged at a plurality of locations in the longitudinal direction cooling water passage 23. A communication passage 30 is connected to each cooling water outlet 23a. Each communication passage 30 extends along the vertical direction, and each tip thereof is connected to the intake-side cooling water inlet passage 11 of the upper water jacket 10.

  The short direction cooling water passage 24 is disposed between the cylinders C. The short direction cooling water passages 24 are arranged at a plurality of locations. The short direction cooling water passage 24 is formed so as to intersect the longitudinal cooling water passage 23 along the short direction (Y direction) of the cylinder head 100 so that the cooling water flows in the short direction. It has become.

  The short direction cooling water passage 24 includes a cooling water inlet side passage 24 a formed on the intake side with respect to the longitudinal direction cooling water passage 23, and a cooling water outlet side passage 24 b formed on the exhaust side. The cooling water inlet side passage 24a and the cooling water outlet side passage 24b communicate with the longitudinal cooling water passage 23, respectively.

  The cooling water inlet side passage 24a branches in two directions, and the leading ends of the branch passages communicate with the intake side cooling water inlet 401, respectively.

  The cooling water outlet side passage 24b is formed in a shape (a shape with dots) such that the cooling water flows around the exhaust valve 306. The cooling water outlet side passage 24 b is processed into a groove shape, and the bottom surface of the passage (the bottom surface of the portion with dots) is lower than the bottom surface of the longitudinal cooling water passage 23. That is, the bottom surface of the coolant outlet side passage 24b is formed close to the combustion chamber 300a.

  In the present embodiment, the flow passage area between the plug-around cooling water passage 22 and the cooling water outlet 23a (communication passage 30) is made larger than the flow passage area of the inter-exhaust-port cooling water passage 21. Yes. Further, the pressure loss between the cooling water passage 22 around the plug and the cooling water outlet 23a (communication passage 30) is made smaller than the pressure loss of the cooling water inlet side passage 24a of the short direction cooling water passage 24.

-Flow of cooling water-
Next, the flow of cooling water in the water jacket of the cylinder head 100 will be described with reference to FIGS.

  First, the cooling water rising from the block water jacket 201 flows into the inter-exhaust-port cooling water passage 21 formed between the exhaust ports 304 of each cylinder C through the exhaust-side cooling water inlet (exhaust-side gasket hole) 402. The exhaust ports can be cooled by the cooling water flowing through the cooling water passage 21 between the exhaust ports. At this time (when the cooling water flows into the cooling water passage 21 between the exhaust ports), the cooling water flows upward from the lateral flow state (the state in the block water jacket 201: see FIG. 3). The cooling water from the jacket 201 flows into the cooling water passage 21 between the exhaust ports while turning.

  The cooling water flowing while turning in the cooling water passage 21 between the exhaust ports flows into the cooling water passage 22 around the plug. The inflowing cooling water flows in the plug-around cooling water passage 22, but since the height of the plug-around cooling water passage 22 is high, the cooling water flows upward. Then, the cooling water flowing out from the plug-around cooling water passage 22 flows into the longitudinal cooling water passage 23. Here, since the cross-sectional area between the plug-around cooling water passage 22 and the cooling water outlet 23a (communication passage 30) is large and the pressure loss is small, the cooling water (upward flow) discharged from the plug-around cooling water passage 22 The cooling water) easily flows into the longitudinal cooling water passage 23 and is easily drawn into the cooling water outlet 23a (communication passage 30). Thereby, most of the cooling water from the cooling water passage 21 between the exhaust ports flows above the longitudinal cooling water passage 23 and flows into the upper water jacket 10 through the cooling water outlet 23a (communication passage 30). Become. A part (excess flow) of the cooling water flowing out from the cooling water passage 22 around the plug flows into the cooling water outlet side passage 24b of the short direction cooling water passage 24 (see the broken line arrow in FIG. 4), and the exhaust valve. This contributes to cooling of 306, the combustion chamber 300a, and the like.

  As described above, by flowing the cooling water through the cooling water passage 21 between the exhaust ports, the space between the exhaust ports 304 can be reliably cooled. In addition, by raising the cooling water from the cooling water passage 21 between the exhaust ports to the upper water jacket 10 as it is, a sufficient amount of cooling water to the upper water jacket 10 can be secured.

  On the other hand, the cooling water that has entered the short-side cooling water passage 24 through the intake-side cooling water inlet (intake-side gasket hole) 401 flows through the cooling water inlet-side passage 24a and then flows into the longitudinal cooling water passage 23. However, as described above, the cooling water from the inter-exhaust-port cooling water passage 21 has already flowed above the passage of the inflow portion, so that the longitudinal cooling water passage 23 extends from the cooling water inlet side passage 24a. The cooling water that has flowed into the channel flows to the lower side of the passage. That is, the cooling water flowing in the short direction cooling water passage 24 flows on the side close to the combustion chamber 300a, and the combustion chamber 300a can be effectively cooled. In addition, since the shape of the coolant outlet side passage 24b of the short direction coolant passage 24 is configured to wrap around the exhaust valve 306, the exhaust valve 306 can be effectively cooled. Furthermore, since the flow path bottom surface of the coolant outlet side passage 24b is configured to be close to the combustion chamber 300a, the combustion chamber 300a can be further effectively cooled.

  As described above, according to the present embodiment, the space between the exhaust ports can be reliably cooled while the amount of cooling water to the upper water jacket 10 is ensured, and the exhaust valve and the combustion chamber 300a are effective. Can be cooled.

-Other embodiments-
In addition, embodiment disclosed this time is an illustration in all the points, Comprising: It does not become a basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. Further, the technical scope of the present invention includes all modifications within the scope and meaning equivalent to the scope of the claims.

  For example, in the above embodiment, cooling water is introduced into the short-side cooling water passage 24 from the intake side through the intake-side cooling water inlet 401, but cooling water is introduced into the short-side cooling water passage 24 from the exhaust side. You may make it do.

  The present invention can be effectively used for a cylinder head in which an upper water jacket and a lower water jacket are formed.

DESCRIPTION OF SYMBOLS 100 Cylinder head 10 Upper water jacket 20 Lower water jacket 21 Cooling water passage between exhaust ports 22 Cooling water passage around plug 23 Longitudinal cooling water passage 23a Cooling water outlet 24 Short cooling water passage 24a Cooling water inlet side passage 24b Cooling Water outlet side passage 30 Communication passage 200 Cylinder block 201 Block water jacket 300 Engine 300a Combustion chamber 303 Intake port 304 Exhaust port 305 Intake valve 306 Exhaust valve 307 Spark plug C cylinder 400 Gasket 401 Intake side gasket hole (intake side cooling water inlet)
402 Exhaust side gasket hole (exhaust side cooling water inlet)

Claims (1)

A cylinder head in which at least two intake ports and two exhaust ports are formed for each of a plurality of cylinders of an engine, and a spark plug is provided,
The cylinder head is formed with an upper water jacket and a lower water jacket,
The lower water jacket is
An exhaust-side cooling water inlet into which cooling water from a cylinder block below the cylinder head flows;
An inter-exhaust-port cooling water passage formed between the exhaust ports of each of the cylinders and flowing the cooling water flowing in from the exhaust-side cooling water inlet toward the spark plug;
A cooling water passage around the plug connected to the cooling water passage between the exhaust ports and flowing cooling water around the spark plug;
A longitudinal cooling water passage formed over the plurality of cylinders and through which cooling water flows in the longitudinal direction of the cylinder head;
A cooling water outlet formed at a position above the longitudinal cooling water passage and between adjacent cylinders;
A communication path communicating the cooling water outlet and the upper water jacket;
A short-direction cooling water passage that is formed at a position between adjacent cylinders so as to intersect the longitudinal cooling water passage and in which the cooling water flowing from the lower cylinder block flows in the short-side direction of the cylinder head. ,
The short-side cooling water passage is formed in a shape such that the cooling water flows around the exhaust valve, and is processed into a groove shape so that the bottom surface of the passage is lower than the bottom surface of the longitudinal cooling water passage. It has a water outlet side passage,
The cooling water passage around the plug is connected to the cooling water passage in the longitudinal direction, and a cross-sectional area between the cooling water passage around the plug and the cooling water outlet is a passage disconnection of the cooling water passage between the exhaust ports. Cylinder head characterized by being larger than the area.

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