JP2011169272A - Cylinder head structure in multi-cylinder internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve rigidity in a portion of a boss part when collecting exhaust ports 6, 7, 8 in each cylinder A, B, C into one collecting exhaust outlet 12 in an interior of a cylinder head 3, opening the collecting exhaust outlet 12 in a side face of the cylinder head, providing plural boss parts 24, 25, 26 in a circumference surrounding the collecting exhaust outlet of side faces of the cylinder head, and carrying out flange joining of an exhaust pipe 23 communicating with the collecting exhaust outlet to the boss parts. <P>SOLUTION: In the cylinder head structure, an upper side boss part 24 of the boss parts is integrally joined to a bearing part 20 for a cam shaft provided in a valve system chamber 5 in a top face of the cylinder head. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a structure of a cylinder head configured such that, among cylinder heads in an internal combustion engine having a plurality of cylinders, exhaust ports from the respective cylinders are gathered in one collective exhaust outlet inside the cylinder head. It is.

In Patent Documents 1 to 3 as prior art,
“In a cylinder head of a multi-cylinder internal combustion engine, the exhaust ports for each cylinder arranged in a line along the crankshaft are gathered in one collective exhaust outlet inside the cylinder head, and this one collective exhaust outlet is It opens to the exhaust side long side surface of the left and right long side surfaces of the cylinder head. "
It is described that the configuration is as follows.

In particular, among the prior art, Patent Document 1
“When the exhaust pipe from the collective exhaust outlet to the atmosphere is flange-joined with a plurality of bolts to the exhaust-side long side face of the cylinder head, the collective exhaust outlet of the exhaust-side long side face The flange bosses are integrally provided at a plurality of portions surrounding the outside of the boss, and the flange joint bolts are screwed into the female screw holes formed in the bosses.
It is described.

JP 2000-161129 A JP 2007-162591 A Japanese Patent Application Laid-Open No. 2007-192086

  According to the configurations described in these prior arts, the number of bolts required to flange-connect the exhaust pipe to the exhaust-side long side surface of the cylinder head is the same as the exhaust port that collects the exhaust ports in each cylinder on the exhaust-side long side surface. Less than when manifolds are flanged.

  However, in this type of cylinder head, a passage for collecting the exhaust ports of the respective cylinders into one collective exhaust outlet is formed as a large cavity, and a general cylinder head (each As in the case of the exhaust port not being assembled inside), a cooling water jacket as a cavity, a valve mechanism chamber in which the upper surface of the cylinder head is recessed, and an oil return passage from the valve mechanism chamber are formed. Therefore, the rigidity of the portion of the cylinder head where the collective exhaust outlet opens, that is, the portion where the exhaust pipe is flanged is lower than that of a general cylinder head.

  And in the structure of the said patent document 1, each in the flange boss | hub part for flange connection of the said exhaust pipe is formed in the inside of the said cylinder head seeing from planar view and the direction of a crankshaft line. It is located outside the valve mechanism chamber, the cooling water jacket, the ignition device mounting hole, and the oil dropping passage.

  In particular, among the boss portions, the upper boss portion located above the exhaust pipe has the valve operating mechanism chamber even though the load acting on the upper boss portion is larger than the load acting on the other boss portions. Since the rigidity of the upper boss portion is low, there is a risk of poor connection and deformation of the cylinder head when the flange of the exhaust pipe is connected to the cylinder head. There was a problem of being big.

  Further, in Patent Document 1, the lower boss portion located below the exhaust pipe among the boss portions is disposed outside the cooling water jacket and the oil return passage formed inside the cylinder head. Therefore, the rigidity at the lower boss portion was also low.

  In the present invention, a camshaft bearing is integrally provided in the valve mechanism chamber in the cylinder head, and the cylinder head has a thick portion through which a head bolt for fastening to the cylinder block passes. Focusing on this, it is a technical problem to solve these problems by using them.

In order to achieve this technical problem, claim 1
“The exhaust ports of the cylinders lined up along the crank axis are gathered in one collective exhaust outlet inside the cylinder head, and this one collective exhaust outlet opens on the side surface of the cylinder head, while in the cylinder head A cylinder head structure in which a boss part for flange-joining the exhaust pipe to the collective exhaust outlet is integrally provided at a plurality of locations on the side surface surrounding the collective exhaust outlet,
At least one upper boss portion located above the collective exhaust outlet among the flange joint boss portions when viewed from the top surface of the cylinder head and when viewed from the direction of the crank axis. The upper boss portion is integrally connected to the cam shaft bearing portion by being arranged at a position where it wraps around the cam shaft bearing portion integrally provided in the valve mechanism chamber on the upper surface of the cylinder head. did. "
It is characterized by that.

Claim 2
“At least one lower boss portion located below the collective exhaust outlet among the flange joining boss portions according to claim 1 is used as a fastening head bolt to a cylinder block of the cylinder head. Was integrally joined to the thick wall part through. "
It is characterized by that.

  In the first aspect of the present invention, “the upper boss portion is wrapped with the cam shaft bearing portion” includes a case where a part of the upper boss portion is wrapped with the cam shaft bearing portion and the upper boss portion. And the case where the whole part wraps around the camshaft bearing part.

  2. The camshaft bearing portion integrally provided in the valve mechanism chamber of the cylinder head is generally configured to integrally connect the exhaust side and the intake side of the cylinder head. With this configuration, the rigidity of the upper boss portion to which a large load is applied among the flange joint boss portions is integrated with the cam shaft bearing portion of the upper boss portion. Since it can be improved as compared with the case of Document 1, it is possible to greatly reduce the possibility of causing poor joining and deformation of the cylinder head when the exhaust pipe is joined to the cylinder head.

  According to a second aspect of the present invention, the rigidity of the lower boss portion of each flange joint boss portion is integrated with the thick portion of the cylinder head through which the head bolt penetrates. Therefore, there is an advantage that the effect of the first aspect can be further promoted.

It is a top view of the cylinder head in an internal combustion engine. FIG. 4 is a longitudinal front view taken along the line II-II in FIGS. 1 and 3. FIG. 3 is a sectional view taken along line III-III in FIG. 2. FIG. 4 is a vertical front view taken along the line IV-IV in FIGS. 1 and 3. FIG. 5 is a side view taken along line VV in FIG. 4. FIG. 6 is a VI-VI plan sectional view of FIGS. 2 and 4.

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

  In these drawings, reference numeral 1 denotes an internal combustion engine in which three cylinders, that is, a first cylinder A, a second cylinder B, and a third cylinder C are arranged in a line along the crank axis 1a. The cylinder head 3 is fastened to the upper surface of the cylinder block 2 by a plurality of head bolts 4.

  As shown in FIGS. 1 and 3, the plurality of head bolts 4 are provided on the left and right sides of the cylinders A to C between the first cylinder A and the second cylinder B. The upper surface of the cylinder head 3 is disposed on the left and right sides between the B and the third cylinder C, the left and right sides on the outside of the first cylinder A, and the left and right sides on the outside of the third cylinder C. In this configuration, the cylinder head 3 is vertically penetrated from the inner bottom surface 5a of the valve operating mechanism chamber 5 formed in a recess, and then screwed into the cylinder block 2.

  Inside the cylinder head 3, there are two exhaust ports 6 for the first cylinder A, two exhaust ports 7 for the second cylinder B, and two exhaust ports 8 for the third cylinder C. Are provided, and a cooling water jacket 9 is formed.

  Moreover, as shown in plan view (FIG. 1), one longitudinal side surface (exhaust side longitudinal side surface) 10 of the left and right longitudinal side surfaces 10 and 11 extending in parallel with the crank axis 1a of the cylinder head 3 is A right side portion of a second cylinder (intermediate cylinder) B located between the first cylinder (outer cylinder) A and the third cylinder (outer cylinder) C located outside the cylinders A, B, C; Alternatively, one collective exhaust outlet 12 opens at a portion close to this.

  Although not shown in the drawing, the intake port 13 in each of the cylinders A, B, and C is opened on the other longitudinal side surface (intake side longitudinal side surface) 11 of the left and right longitudinal side surfaces 10 and 11 of the cylinder head 3. is doing.

  Both exhaust ports 7 in the second cylinder (intermediate cylinder) B extend in the direction of the collective exhaust outlet 12 and then communicate directly with the collective exhaust outlet 12. The partition wall 14 is provided so as to extend toward the collective exhaust outlet 12.

  Inside the partition wall 14, an oil drop passage 15 or a blow-by for guiding lubricating oil in the valve mechanism chamber 5 on the upper surface of the cylinder head 3 to a crank chamber (not shown) in the lower portion of the cylinder block 2. A gas passage is formed.

  On the other hand, both the exhaust ports 6 in the first cylinder (outer cylinder) A located outside the second cylinder (intermediate cylinder) B among the cylinders A, B, C are connected to the second cylinder (intermediate cylinder) B. Are gathered in the exhaust passage 16 for the first cylinder while curving inwardly toward.

  Further, the exhaust ports 8 in the third cylinder (outer cylinder) C located outside the second cylinder (intermediate cylinder) B among the cylinders A, B, and C are connected to the second cylinder (intermediate cylinder). ) Collecting in the exhaust passage 17 for the third cylinder while curving inward toward B.

  Both the exhaust passage 16 for the first cylinder and the exhaust passage 17 for the third cylinder extend obliquely outward toward the collective exhaust outlet 12 and then communicate with the collective exhaust outlet 12. It has become.

  That is, the exhaust ports 6, 7, 8 in each of the cylinders A, B, C are gathered in one collective exhaust outlet 12 inside the cylinder head 3, and this one collective exhaust outlet 12 is connected to the cylinder head. The left and right long side surfaces 10 and 11 in FIG.

  A cylinder 18 for attaching a spark plug is integrally provided at each cylinder A, B, C portion of the cylinder head 3 so as to protrude upward from the valve mechanism chamber 5.

  Further, in the inside of the valve mechanism chamber 5 in the cylinder head 3, a portion between the cylinders A, B, and C is provided with a bearing portion 20 that supports the lower half of the exhaust valve cam shaft 19 and an intake valve. A bearing portion 22 that pivotally supports the lower half of the camshaft 21 is integrally provided, and both the exhaust-side bearing portion 20 and the intake-side bearing portion 22 are provided with a cylinder for mounting the spark plug. The body 18 is integrally coupled.

  At the exhaust side long side surface 10 of the cylinder head 3, at least three boss portions 24, 25, 26 for flange-joining the exhaust pipe 23 to the atmosphere with respect to the collective exhaust outlet 12 are provided in the collective exhaust outlet 12. It is provided integrally so as to surround the periphery. Although not shown, the exhaust pipe 23 is curved from the downstream side of the connecting portion with the cylinder head, extends in a direction along the cylinder block, passes through the lower side of the vehicle, and is opened to the atmosphere at the rear of the vehicle. An exhaust gas purification catalyst is built in the side of the block.

  The three boss portions 24, 25, 26 are formed by locating one boss portion 24 on the upper side and two bosses on the lower left and right sides of the collective exhaust outlet 12 when the exhaust side longitudinal side surface 10 is viewed from a right angle. The portions 25 and 26 are disposed in a triangular shape.

  In this case, in the collective exhaust outlet 12, the distance L1 from the center of the collective exhaust outlet 12 to the upper boss portion 24 is larger than the distance L2 from the center of the collective exhaust outlet 12 to the lower boss portions 25 and 26. Thus, since it is eccentric to the bottom side with respect to the triangle, the collective exhaust outlet 12 can be brought close to the lower surface of the cylinder head 3, so that the height of the cylinder head 3 can be reduced.

  Female screw holes 24a, 25a, and 26a are formed in each of the boss portions 24, 25, and 26, and the exhaust pipe 23 has bolts 27 that pass through the flange portion 23a fixed to one end thereof. The cylinder head 3 is detachably flange-bonded to the exhaust side long side surface 10 by being screwed and fastened to the female screw holes 24a, 25a, 26a in the boss portions 24, 25, 26. Reference numeral 28 denotes a sealing gasket that is sandwiched between the flanges when the flanges are joined.

  Of the boss portions 24, 25, 26, the upper boss portion 24 is used for the exhaust valve camshaft in the valve mechanism chamber 5 in a plan view (FIG. 1) when the upper surface of the cylinder head is viewed. In a side view (FIG. 2) when viewed from the direction of the crank axis, in addition to being disposed at a position where a part or the whole of the upper boss portion 24 wraps (overlaps) with respect to the bearing portion 20. The exhaust valve camshaft bearing portion 20 in the valve operating mechanism chamber 5 is disposed at a position where a part or the whole of the upper boss portion 24 wraps (overlaps). The camshaft bearing portion 20 is integrally coupled.

  On the other hand, of the boss portions 24, 25, 26, the lower boss portions 25, 26 are located between the cylinders A, B, C as shown in FIGS. The lower boss portions 25 and 26 are disposed in a portion directly beside the head bolt 4 or a portion close thereto, and the lower boss portions 25 and 26 are integrally formed with a thick portion 29 of the cylinder head 3 through which the head bolt 4 passes. It is configured to be combined.

  In this configuration, of the boss portions 24, 25, and 26 for flange connection of the exhaust pipe 23, the upper boss portion 24 is integrated with the camshaft bearing portion 20 provided integrally in the valve operating mechanism chamber 5. The rigidity of the upper boss portion 24 to which a large load acts is integrally provided in the valve operating mechanism chamber 5 among the flange joint boss portions 24, 25, and 26. The camshaft bearing portion 20 can be used to greatly improve.

  Further, the lower boss portions 25, 26 of the flange boss portions 24, 25, 26 are integrally connected to a thick portion 29 through which the head bolt 4 passes in the cylinder head 3. The rigidity of the lower boss portions 25 and 26 can be greatly improved by using the thick portion 29 through which the head bolt 4 passes.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 1a Crank axis A, B, C Cylinder 2 Cylinder block 3 Cylinder head 4 Head bolt 5 Valve mechanism room 6, 7, 8 Exhaust port 9 Cooling water jacket 10 Exhaust side long side surface 12 Collective exhaust outlet 19 For exhaust valves Cam shaft 20 Cam shaft bearing 23 Exhaust pipe 23a Flange 24, 25, 26 Flange joint boss 27 Bolt 29 Thick part

Claims (2)

The exhaust ports of the respective cylinders arranged along the crank axis are gathered in one collective exhaust outlet inside the cylinder head, and this one collective exhaust outlet opens to the side face of the cylinder head, while the side face of the cylinder head A cylinder head structure in which bosses for flange-joining the exhaust pipe to the collective exhaust outlet are integrally provided at a plurality of locations around the collective exhaust outlet.
At least one upper boss portion located above the collective exhaust outlet among the flange joint boss portions when viewed from the top surface of the cylinder head and when viewed from the direction of the crank axis. The upper boss portion is integrally connected to the cam shaft bearing portion by being arranged at a position where it wraps around the cam shaft bearing portion integrally provided in the valve mechanism chamber on the upper surface of the cylinder head. A cylinder head structure in a multi-cylinder internal combustion engine.   In the description of claim 1, at least one lower boss portion located below the collective exhaust outlet among the flange joint boss portions, and a head bolt for fastening to a cylinder block among the cylinder heads. A cylinder head structure in a multi-cylinder internal combustion engine, wherein the cylinder head structure is integrally coupled to a through-wall thick part.

Images