JP2008150960A - Cylinder block for multi-cylinder internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder block 1 for a multi-cylinder internal combustion engine wherein a plurality of cylinders 2, 3, 4, 5 are aligned in a row, and cooling-fluid jackets 8 for respective cylinders are formed on both sides of the row of the cylinders, and warped deformation of the cylinder block are reduced in fastening a cylinder head on the upper surface 1a, and cooling performance is improved. <P>SOLUTION: With respect to the depth from the upper surface 1a of the cylinder block 1 in the cooling-fluid jackets 8, H1 in both the end parts in the cylinder-row direction is made deep, and H2 in the central part in the cylinder-row direction is made shallow. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to the structure of a cylinder block in a multi-cylinder internal combustion engine having a plurality of cylinders arranged in a row.

  In general, in a multi-cylinder internal combustion engine, a cylinder head that closes the top of each cylinder is sandwiched between an upper surface of a cylinder block in which cylinders in each cylinder are arranged in a row, and a sealing gasket is sandwiched between the cylinder heads. The configuration is such that a plurality of head bolts arranged along both sides of the cylinder row are fastened. In this case, the conventional cylinder block is described in, for example, Patent Documents 1 and 2 as the prior art. As shown, the cooling liquid jacket surrounding each cylinder is formed so as to extend in the cylinder row direction on the left and right sides of the cylinder row with the upper surface of the cylinder block opened.

  However, in the case of such a coolant jacket structure, when the cylinder head is fastened to the upper surface of the cylinder block with a plurality of head bolts arranged along both sides of the cylinder row, the cylinder head Since the block is more likely to warp and deform in a bow shape with respect to the cylinder head so that both end portions in the cylinder row direction of the upper surface of the cylinder block are closer to the cylinder head than the center portion in the cylinder row direction. There is a tendency that the fastening to the cylinder head in the central portion in the cylinder row direction becomes insufficient.

  Therefore, in the former Patent Document 1, when reinforcing flanges are provided on the left and right longitudinal side surfaces of the upper surface of the cylinder block so as to extend in the direction of the cylinder row, the lateral width of the flange portion is determined in the cylinder row direction. It has been proposed to increase the rigidity in the central portion of the cylinder block in the cylinder row direction by increasing the width in the central portion, thereby reducing warpage deformation in the cylinder block.

Further, in the latter patent document 2, warpage deformation in the cylinder block is reduced by providing a reinforcing rib in a cross shape between the left and right long side surfaces of the cylinder block between the head bolt bosses. Propose to do.
Japanese Patent Laid-Open No. 10-318039 Japanese Patent Laid-Open No. 10-318040

  However, in any of these methods, in order to reliably prevent warpage deformation, the protruding height of the reinforcing flange portion or the reinforcing rib has to be made considerably high. In addition to a large increase in the size of the cylinder block, and in turn, an increase in the size of the internal combustion engine, the shape of the cylinder block on both the left and right longitudinal sides is changed or complicated. There was a problem of incurring a cost increase required for casting.

  It is a technical object of the present invention to solve these problems and to improve the cooling performance for each cylinder in the coolant jacket of the cylinder block.

In order to achieve this technical problem, claim 1 of the present invention provides:
“In a cylinder block for a multi-cylinder internal combustion engine comprising a plurality of cylinders arranged in a row, and a coolant jacket for each cylinder extending in the cylinder row direction on the left and right sides of the cylinder row,
A depth dimension from the upper surface of the cylinder block in the coolant jacket is configured to be deep at both end portions in the cylinder row direction and shallow at a central portion in the cylinder row direction. "
It is characterized by that.

Further, claim 2 of the present invention is
“In claim 1, the coolant inlet to the coolant jacket is provided in a portion of the coolant jacket that is deep from the upper surface of the cylinder block.”
It is characterized by that.

  The depth dimension from the upper surface of the cylinder block in the coolant jacket of the cylinder block is configured to be deep at both end portions in the cylinder row direction and shallow at the center portion in the cylinder row direction. The rigidity of the central portion of the cylinder block in the cylinder row direction is not increased without significantly increasing the protruding height of the reinforcing flange and reinforcing rib on the longitudinal side surface. Therefore, warpage deformation when the cylinder block is fastened to the cylinder head can be reliably reduced without incurring an increase in size, a significant increase in weight, and an increase in cost required for casting or die casting.

  By the way, the thermal load on each cylinder in the cylinder block tends to be high in a portion close to the upper surface of the cylinder block in each cylinder and high in a cylinder located in the center portion in the cylinder row direction among the cylinders. , Among the cylinders located in the central portion, the heat load on the portion near the upper surface of the cylinder block is the highest.

  In contrast, the depth dimension from the upper surface of the cylinder block in the coolant jacket for each cylinder is configured to be deep at both end portions in the cylinder row direction and shallow at the center portion in the cylinder row direction. The flow rate of the coolant in the coolant jacket is the fastest because the passage cross-sectional area is reduced in the portion of the coolant jacket where the depth from the upper surface of the cylinder block is shallow. It is possible to reliably improve the cooling performance for the portion of the cylinder located at the center where the heat load is highest.

  In particular, the configuration described in claim 2 has an advantage that the cooling performance can be further improved because the inflow resistance when the coolant is introduced into the coolant jacket can be lowered.

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

  In this figure, reference numeral 1 denotes a cast or die-cast cylinder block. In this cylinder block 1, a plurality (four in this embodiment) of cylinders 2, 3, 4, 5 are shown in plan view. In FIG. 1, they are arranged in a line along the crank axis 6.

  The cylinder block 1 is provided with a plurality of head bolts 7 configured to protrude upward from the upper surface 1a in the row direction of the cylinders 2, 3, 4 and 5 in plan view (FIG. 1). The cylinder head (not shown) is fastened to the upper surface 1a of the cylinder block 1 with a gasket (not shown) sandwiched between the head bolts 7 at right and left sides. It is configured.

  Furthermore, the cylinder block 1 has a coolant jacket 8 surrounding the cylinders 2, 3, 4, and 5 opened in the upper surface of the cylinder block 1. , 5 so as to extend along the left and right sides in the column direction.

  And the depth dimension from the upper surface of the said cylinder block 1 in the said coolant jacket 8 is made into the 1st cylinder 2 and the 4th cylinder 5 which are located in the both ends of the said row direction among the said cylinders 2, 3, 4, 5. The depth of the second cylinder 3 and the third cylinder 4 located at the center in the column direction among the cylinders 2, 3, 4 and 5 is shallower than H2.

  Further, the coolant inlet 9 to the coolant jacket 8 is a portion of the coolant jacket 8 in which the depth from the upper surface of the cylinder block 1 is increased to H1, that is, each of the cylinders 2, 3, 4, and 5. Of these, the first cylinder 2 is provided.

  Note that the coolant flowing into the coolant jacket 8 from the coolant inlet 9 flows in the coolant jacket 8 in the direction of the column through the one side of the cylinder row, as is well known in the art. A U-turn is made at the portion of 4 cylinders 5 and the other side of the cylinder row flows in the direction of the row. In the middle of this flow, it flows out from each cylinder 2, 3, 4, 5 to the coolant jacket in the cylinder head. It is structured as follows.

  A cylinder head is fastened to the upper surface of the cylinder block 1 by a plurality of bed bolts 7 with a sealing gasket interposed therebetween.

  At the time of this fastening, the cylinder block 1 is warped so that its upper surface 1a becomes an arcuate shape with respect to the cylinder head as indicated by a two-dot chain line A in FIG. It will tend to deform.

  In this case, the depth dimension from the upper surface of the cylinder block 1 in the coolant jacket 8 provided along the left and right both sides in the column direction of the cylinders 2, 3, 4 and 5 of the cylinder block 1 is defined as Of the cylinders 2, 3, 4 and 5, the portions of the first cylinder 2 and the fourth cylinder 5 located at both ends in the row direction are deepened to H1, and the row of the cylinders 2, 3, 4 and 5 is the row. Since the second cylinder 3 and the third cylinder 4 located at the center in the direction are shallow with H2, the center portion in the cylinder row direction of the cylinder block, each cylinder 2, 3, 4, 5 Among them, the rigidity of the second cylinder 3 and the third cylinder 4 can be improved, so that warping deformation when the cylinder block is fastened to the cylinder head can be reliably reduced.

  Further, the heat load on the cylinders 2, 3, 4 and 5 in the cylinder block 1 is high in the portions of the second cylinder 3 and the third cylinder 4 located in the center, and the second cylinder 3 and the third cylinder. 4 is highest on the upper surface 1 a of the cylinder block 1.

  In this case, the depth dimension from the upper surface 1a of the cylinder block 1 in the coolant jacket 8 for each of the cylinders 2, 3, 4 and 5 is set to H1 in the portions of the first cylinder 2 and the fourth cylinder 5 located at both ends. A portion where the heat load on the second cylinder 3 and the third cylinder 4 is the highest in the coolant jacket 8 due to the shallower H2 in the portion of the second cylinder 3 and the third cylinder 4 located deep and in the center. Since the passage cross-sectional area can be reduced and the flow rate of the coolant can be increased in this portion, uniform cooling performance can be ensured for all the cylinders 2, 3, 4, and 5.

  Further, the coolant inlet 9 to the coolant jacket 8 and the depth of the coolant jacket 8 from the upper surface 1a of the cylinder block 1 are provided in a portion deeper than H1, thereby the coolant jacket. The inflow resistance when the coolant is introduced into the coolant 8 can be lowered.

  Needless to say, the present invention can be similarly applied to a cylinder block in a V-type internal combustion engine.

It is a top view which shows embodiment of this invention. FIG. 2 is a sectional view taken along line II-II in FIG. 1. FIG. 3 is a sectional view taken along line III-III in FIG. 1. FIG. 4 is a sectional view taken along line IV-IV in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder block 1a Cylinder block upper surface 2, 3, 4, 5 Cylinder 6 Crank axis 7 Head bolt 8 Coolant jacket 9 Coolant inlet

Claims (2)

A cylinder block for a multi-cylinder internal combustion engine comprising a plurality of cylinders arranged in a row, and a coolant jacket for each cylinder extending in the cylinder row direction on both the left and right sides of the cylinder row,
A multi-cylinder characterized in that a depth dimension from an upper surface of the cylinder block in the coolant jacket is deep at both end portions in the cylinder row direction and shallow at a central portion in the cylinder row direction. Cylinder block for internal combustion engines.   2. The multi-cylinder internal combustion engine according to claim 1, wherein the coolant inlet to the coolant jacket is provided in a portion of the coolant jacket that is deep from the upper surface of the cylinder block. Cylinder block.

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