JP2009250193A - Blow-by gas passage structure of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To separate oil mist in a blow-by gas passage from a crankcase to an oil separator chamber in an internal combustion engine provided with a cylinder block provided with the crankcase in a lower part, a cylinder head of the upper face, a bearing part 11 for a camshaft of the upper face, a bearing cap body of the upper face, and a head cover covering the upper face of the cylinder head and provided with the oil separator chamber of blow-by gas. <P>SOLUTION: In this blow-by gas passage 17 of a blow-by gas passage structure, a passage 17b from the cylinder block 1 side is branched into a plurality of passages 17c in the cylinder head 4, and a plurality of passages 17d communicated with the plurality of branched passages are opened in the upper face of the bearing part. The plurality of passages opened in the upper face of the bearing part are joined in a passage 17e leading to the oil separator chamber 16 in a recessed part 19 of a joining surface between the bearing part and the bearing cap body 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a blow-by gas passage structure for guiding blow-by gas in a crankcase at a lower part of a cylinder block to an oil separator chamber provided in a head cover in an internal combustion engine.

  In recent internal combustion engines, an oil separator chamber is provided in a head governor that covers the valve mechanism chamber on the upper surface of the cylinder head, and blowby gas in a crankcase is introduced into the oil separator chamber via a blowby gas passage. After separating the mist, the mist is sent to a blow-by gas processing unit such as an intake system.

In this case, the conventional blow-by gas passage extends linearly through the cylinder block and the cylinder head in the direction of the cylinder axis, as described in Patent Documents 1 to 5, for example. It is configured to be provided in.
Japanese Patent Laid-Open No. 10-317940 JP-A-8-93436 JP-A-6-10645 Japanese Utility Model Publication No. 1-88012 Japanese Utility Model Publication No. 3-73606

  However, as described in Patent Documents 1 to 5 and the like, the conventional blow-by gas passage is configured to extend substantially linearly along the cylinder axis, and an oil mist in the blow-by gas passage. The oil mist discharged together with the blow-by gas from the oil separator chamber is increased by the amount that the oil mist is hardly separated in the blow-by gas passage. .

  An object of the present invention is to provide a blow-by gas passage that solves this problem.

In order to achieve this technical problem, claim 1 of the present invention provides:
“A cylinder block having a crankcase at a lower portion, a cylinder head having a bearing portion for a cam shaft on an upper surface, a bearing cap body on the upper surface of the bearing portion, and a head governor covering the upper surface of the cylinder head, and the head cover In addition, in the blow-by gas passage structure of the internal combustion engine having an oil separator chamber for blow-by gas,
A blow-by gas passage extending from the crankcase to the oil separator chamber is provided in the cylinder block, the cylinder head, the bearing portion, and the bearing cap body. The blow-by gas passage is connected to the cylinder block in the cylinder head. A passage from the side branches into a plurality of passages, and the plurality of branched passages pass through the bearing portion, and a plurality of passages that pass through the bearing portion include the bearing portion and the bearing cap body. In the recess portion provided in the joint surface, the bearing cap body passes through the passage leading to the oil separator chamber. "
It is characterized by that.

Further, claim 2 in the present invention is
“In the first aspect of the present invention, the plurality of passages opened on the upper surface of the bearing portion are tapered toward the recess portion.”
It is characterized by that.

Furthermore, claim 3 in the present invention includes
“In the description of claim 2, the bearing portion is configured separately from the cylinder head, and a plurality of passages penetrating the bearing portion are tapered toward the recess portion. "
It is characterized by that.

  According to the first aspect of the present invention, the blow-by gas from the crankcase to the oil separator chamber first changes the direction of flow and flows to the inner wall surface when the passage from the cylinder block side branches into a plurality of passages in the cylinder head. The oil mist is separated by collision and volume expansion / contraction.

  Next, when the blow-by gas joins the passages from the plurality of passages in the recesses of the joint surface between the bearing portion and the bearing cap body, the flow direction is changed, the blow-by gases collide with each other, the collision with the inner wall surface, and the volume. The oil mist is separated by expansion and contraction of the oil.

  In addition, the blow-by gas passage is branched into a plurality of passages in the middle thereof, and further, the blow-by gas having a pulsation caused by the reciprocation of the piston is obtained by joining the plurality of passages. The blowby gas branched into a plurality of pulsations with the same phase, and the violent collision with the pulsations at the same phase at the merging point, in other words, at the merging point Since the collision between blow-by gases becomes intense, the oil mist separation action can be further promoted.

  Together, the oil mist separation in the blow-by gas passage can be greatly improved as compared with the conventional case, so that the oil mist discharged together with the blow-by gas from the oil separator chamber can be reliably ensured. Can be reduced.

  Moreover, since the separation of the oil mist in the blow-by gas passage can be promoted, there is an advantage that the oil separator chamber can be simply configured or downsized.

  In addition, by joining the passages from the plurality of passages to the passage to the oil separator chamber at the concave portion of the joint surface between the bearing portion and the bearing cap body, the joining can be realized with a simple configuration that is easy to process. .

  Further, according to the configuration of claim 2, when blow-by gas can be expanded by volume when entering the recess, oil mist can be separated by this volume expansion and when blow-by gas enters the recess. And the oil mist separating action due to the flow direction change in the recess, the collision between blow-by gases, the collision with the inner wall surface, the expansion and contraction of the volume, etc. can be further improved. The oil mist separation in the interior can be greatly promoted.

  Furthermore, according to the configuration of claim 3, when the bearing portion is die-cast or cast, the plurality of passages provided through the bearing portion are formed in a tapered shape, thereby increasing the draft angle of the passage. Since it can be set, it can be easily formed at low cost by die cutting without using a core die.

  Embodiments of the present invention will be described below with reference to FIGS.

  In these drawings, reference numeral 1 denotes a cylinder block in which a plurality of cylinder bores 2 are provided in a line in the direction of the crank axis 3, and reference numeral 4 denotes the top of each cylinder bore 2 on the upper surface 1 a of the cylinder block 1. Each cylinder head is arranged so as to close the cylinder block, and a crankcase is provided at the lower part of the cylinder block 1 although not shown.

  The lower surface 4b of the cylinder head 4 is in close contact with the upper surface 1a of the cylinder block 1, and a plurality of head bolts 5 disposed on the left and right sides of the crank axis 3 between the cylinder bores 2, respectively. Fastened to the cylinder block 1.

  Although not shown, a sealing gasket is provided between the upper surface 1a of the cylinder block 1 and the lower surface 4b of the cylinder head 4.

  Inside the cylinder head 4, an intake port 6 into the cylinder bore 2 is formed so as to open to a longitudinal side surface 4c extending in parallel with the crank axis 3 of the cylinder head 4, and the longitudinal side surface 4c The intake manifold 7 for distributing new air from an air cleaner (not shown) to each intake port 6 is detachably mounted by fastening its flange portion 8 with a plurality of bolts 9. ing.

  Further, on the upper surface 4a of the cylinder head 4, there is a bearing portion 11 for pivotally supporting the lower half of an intake valve cam shaft 10 and an exhaust valve cam (not shown). A bearing cap body 12 for the upper half of the intake valve cam shaft 10 is disposed on the upper surface 11a of the bearing portion 11, and a lower surface 12b of the bearing cap body 12 is disposed on the upper surface 11a of the bearing portion 11. The bearing portion 11 and the bearing cap body 12 are fastened to the cylinder head 4 by a plurality of bolts 13 that pass through them simultaneously.

  A head cover 14 for covering the entire upper surface of the cylinder head 4 is detachably attached to the bearing portion 11 by a plurality of bolts 15. The head cover 14 is attached with the intake air. An oil separator chamber 16 having a blowby gas outlet 16 'to a blowby gas processing section such as the manifold 7 is provided.

  Reference numeral 17 denotes a blow-by gas passage for guiding blow-by gas in the crankcase at the lower part of the cylinder block 1 to the oil separator chamber 16 in the head cover 14.

  The blow-by gas passage 17 has a configuration in which a portion between the intake ports 6 extends along the axis 2a of the cylinder bore 2 and is formed in the cylinder block 1 so as to open to the upper surface 1a. A first passage 17a, a second passage 17b formed in the cylinder head 4 so as to open to the lower surface 4b, and a cylinder head 4 formed so as to open in the upper surface 4a. Two (plural) third passages 17c, two (plural) fourth passages 17d formed in the bearing portion 11 so as to open to the upper surface 11a and the lower surface 11b, The bearing cap body 12 is constituted by a single fifth passage 17e formed so as to open to the upper surface 12a.

  One first passage 17 a in the cylinder block 1 and one second passage 17 b in the cylinder head 4 communicate with each other at the joint surface between the cylinder block 1 and the cylinder head 4.

  One second passage 17b and two (a plurality of) third passages 17c in the cylinder head 4 are extended chambers 18 formed in portions between the intake ports 6 inside the cylinder head 4. By communicating with each other, the expansion chamber 18 in the cylinder head 4 branches from one second passage 17b to two (plurality) third passages 17c.

  In this case, the one second passage 17b and the two (plurality) third passages 17c overlap each other as shown in FIG. 3 when viewed from the direction of the axis 2a of the cylinder bore 2. Instead, they are offset from each other in the lateral direction.

  In addition, a part of the expansion chamber 18 has an opening 18b in the longitudinal side surface 4c, and the opening 18b is closed by a flange portion 8 in the intake manifold 7, and a depth from the longitudinal side surface 4c. By increasing the depth to reach the head bolt 5, the internal volume of the expansion chamber 18 is increased and the weight of the cylinder head 4 is reduced.

  In addition, when the cylinder head 4 is cast, the expansion chamber 18 is simultaneously formed by casting using a core mold from the longitudinal side surface 4c. It can also be formed.

  Furthermore, as shown in FIG. 3, as viewed from the direction of the axis 2a of the cylinder bore 2, the inside of the expansion chamber 18 covers a part of the single second passage 17b by a dimension S as appropriate. A raised portion 18a is provided (overlapping), and a part of the blow-by gas flowing into the expansion chamber 18 from the second passage 17b is blown against the raised portion 18a.

  As shown in FIG. 2, the two (plural) fourth passages 17 d penetrating the bearing portion 11 are tapered from the lower surface 11 b toward the upper surface 11 a, and the two in the cylinder head 4. The plurality of third passages 17 c communicate with each other at the joint surface between the cylinder head 4 and the bearing portion 11.

  One fifth passage 17e in the bearing cap body 12 is configured to communicate with the oil separator chamber 16 on the upper surface 12a of the bearing cap body 12, and the fifth passage 17e and the bearing portion 11 are in communication with each other. The two (a plurality of) fourth passages 17d communicate with each other at a recess 19 provided on the lower surface 12b of the bearing cap body 12.

  In other words, the two (a plurality of) fourth passages 17 d in the bearing portion 11 join the one fifth passage 17 e in the bearing cap body 12 in the recess portion 19.

  Even in this case, the one fifth passage 17e and the two (plurality) fourth passages 17d do not overlap with each other in the lateral direction when viewed from the direction of the axis 2a of the cylinder bore 2. It is configured to offset.

  Further, the recessed portion 19 may be provided on the upper surface 11a of the bearing portion 11 instead of being provided on the lower surface 12b of the bearing cap body 12, or the lower surface 12b of the bearing cap body 12; It can be configured to be provided across both the upper surface 11 a of the bearing portion 11.

  In this configuration, blow-by gas in the crankcase at the lower portion of the cylinder block 1 is guided to the oil separator chamber 16 in the head cover 14 via the blow-by gas passage 17.

  In this case, blow-by gas to the oil separator chamber 16 first branches from the second passage 17b communicating with the first passage 17a in the cylinder block 1 into two (plurality) third passages 17c in the cylinder head 4. Sometimes, the oil mist is separated due to flow direction change, collision with the inner wall surface, expansion and contraction of the volume, and the temperature is increased by heat transfer from the cylinder head 4.

  Next, blow-by gas to the oil separator chamber 16 merges from the two (plural) fourth passages 17d communicating with the two (plural) third passages 17c into the fifth passage 17e at the recess 19. In this case, the oil mist is separated by the flow direction change, the collision with the inner wall surface, and the expansion and contraction of the volume.

  Thereby, separation of oil mist in the blowby gas passage 17 can be promoted.

  In this case, two (a plurality of) fourth passages 17 d that pass through the bearing portion 11 and open to the upper surface thereof are tapered toward the recess portion 19, so that the inside of the recess portion 19 is formed. The volume expansion at the end increases, and the oil mist separability can be further improved. On the other hand, when the bearing portion 11 is die-cast or cast, the fourth passage 17d provided through the bearing portion 11 is provided with a core. It can be formed by die cutting without using a die.

  In addition, it is preferable that the taper angle θ in each of the fourth passages 17d penetrating the bearing portion 11 is 5 degrees or more for die cutting.

  In addition, the second passage 17b and the third passage 17c in the cylinder head 4 in the blow-by gas passage 17 communicate with each other via an expansion chamber 18 formed in the cylinder head 4. Then, the second passage 17b is branched into two (a plurality of) third passages 17c in the expansion chamber 18, so that blow-by gas from the second passage 17b enters the expansion chamber 18. The volume of the oil mist expands greatly, and the volume of the expansion chamber 18 contracts greatly from the inside of the expansion chamber 18 toward the third passage 17c, so that the oil mist can be further separated.

  Furthermore, the second passage 17b and the plurality of third passages 17c in the cylinder head 4 in the blow-by gas passage 17 are offset from each other laterally without overlapping each other when viewed from the direction of the axis 2a of the cylinder bore 2. By doing so, it is possible to reliably avoid blow-by gas from the second passage 17b from being blown into the third passage 17c without being subjected to oil-separation separation action in the expansion chamber 18. Can be secured.

  In addition, the fourth passage 17d in the bearing portion 11 and the fifth passage 17e in the bearing cap body 12 are similarly offset laterally without overlapping each other when viewed from the direction of the axis 2a of the cylinder bore 2. By doing so, it is possible to reliably avoid blow-by gas from the fourth passage 17d from being blown into the fifth passage 17e without being subjected to oil-separation separation action in the recess portion 19. Can be secured.

  In the embodiment, the blow-by gas passage 17 and the expansion chamber 18 are opened between the intake ports 6 to the cylinder bores 2 and a part of the expansion chamber 18 is opened to the longitudinal side surface 4c on the intake side. The opening 18b in the expansion chamber 18 is configured to be closed by the intake manifold 7 attached to the intake side longitudinal side surface 4c. However, the present invention is not limited to this. The blow-by gas passage 17 and the expansion chamber 18 are opened at a portion between the exhaust ports from each cylinder bore 2 where the temperature is higher than that at the intake port side, and a part of the expansion chamber 18 is opened at the long side surface on the exhaust side. Thus, the opening 18b in the expansion chamber 18 can be closed by an exhaust manifold that is attached to the longitudinal side surface of the exhaust side.

  In the above embodiment, the bearing 11 is separated from the cylinder head 4 and is fastened to the cylinder head 4. The bearing 11 may be integrated with the cylinder head 4 in this case, and in this case, both the two (plural) third passages 17c and the fourth passage 17d are formed in the recesses. The taper is tapered toward the portion 19.

It is a vertical front 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder bore 2a Cylinder bore axis 3 Crank axis 4 Cylinder head 4a Cylinder head upper surface 4b Cylinder head lower surface 4c Cylinder head long side surface 5 Head bolt 6 Intake port 7 Intake manifold 8 Flange part 10 Intake valve cam shaft 11 Bearing portion 12 Bearing cap body 14 Head cover 16 Oil separator chamber 17 Blow-by gas passage 17a First passage 17b Second passage 17c Third passage 17d Fourth passage 17e Fifth passage 18 Expansion chamber 18a Expansion chamber ridge 18b Expansion chamber opening 19 dent

Claims (3)

A cylinder block having a crankcase at a lower portion, a cylinder head having a bearing portion for a cam shaft on an upper surface, a bearing cap body on the upper surface of the bearing portion, and a head governor covering the upper surface of the cylinder head, , In a blow-by gas passage structure of an internal combustion engine comprising an oil separator chamber for blow-by gas,
A blow-by gas passage extending from the crankcase to the oil separator chamber is provided in the cylinder block, the cylinder head, the bearing portion, and the bearing cap body. The blow-by gas passage is connected to the cylinder block in the cylinder head. A passage from the side branches into a plurality of passages, and the plurality of branched passages pass through the bearing portion, and a plurality of passages that pass through the bearing portion include the bearing portion and the bearing cap body. A blow-by gas passage structure for an internal combustion engine, characterized in that it is configured to join a passage that penetrates the bearing cap body and reaches the oil separator chamber in a recessed portion provided on the joint surface with the internal combustion engine.   2. A blow-by gas passage structure for an internal combustion engine according to claim 1, wherein the plurality of passages opened on the upper surface of the bearing portion are configured to taper toward the concave portion.   The bearing portion according to claim 2, wherein the bearing portion is configured separately from the cylinder head, and a plurality of passages penetrating the bearing portion are configured in a tapered shape toward the recess portion. A blow-by gas passage structure for an internal combustion engine.