WO2007026910A1

WO2007026910A1 - Cylinder block and two-cycle multi-cylinder internal combustion engine with the same

Info

Publication number: WO2007026910A1
Application number: PCT/JP2006/317400
Authority: WO
Inventors: Hisato Hori; Ichirou Fujimura
Original assignee: Daihatsu Motor Co., Ltd.
Priority date: 2005-08-30
Filing date: 2006-08-29
Publication date: 2007-03-08
Also published as: JP2007064054A

Abstract

Two scavenging chambers (8, 9) extending in the direction of a crankshaft axis are formed on both left and right sides of a cylinder row. A scavenging inlet (15) is provided at one end of a cylinder block, and the scavenging inlet is branched and connected to both scavenging chambers. Further, a path (16) for discharging oil from a cylinder head is provided in the cylinder block, inside the branch portion at which the scavenging inlet is branched to both scavenging chambers.

Description

TECHNICAL FIELD The present invention relates to a two-cycle multi-cylinder internal combustion engine comprising a plurality of cylinders among a cylinder block and a two-cycle internal combustion engine. It is about the institution. Background Art Patent Document 1 as a prior art describes a cycle type multi-cylinder internal combustion engine having a plurality of cylinders. In this two-cycle multi-cylinder internal combustion engine, a plurality of cylinders are arranged in a cylinder block side by side in the crankshaft direction, and a scavenging port into the cylinder is provided at a plurality of locations in the circumferential direction in each cylinder. On the other hand, the cylinder block has a scavenging chamber for distributing the intake air (scavenging) compressed by the scavenging pump to each of the scavenging ports in each cylinder. It is the structure of providing so that it may surround. Moreover, in this two-cycle multi-cylinder internal combustion engine, a scavenging inlet from the scavenging pump to the scavenging chamber is provided on one long side surface of the left and right long side surfaces that are flat with the crankshaft axis in the cylinder block. I have to. Patent Document 1: Japanese Laid-Open Patent Publication No. 2000-3 5 6 3 4 2 In the prior art two-cycle multi-cylinder internal combustion engine, as described above, both the left and right longitudinal sides parallel to the crank axis of the cylinder block Since one scavenging inlet from the scavenging pump to the scavenging chamber is provided on one of the longitudinal sides, intake air (scavenging) from the scavenging inlet is supplied to all scavenging ports in each cylinder. In order to evenly distribute the air, the intake air flowing in from the scavenging inlet on one longitudinal side of the scavenging chamber must be distributed throughout the scavenging chamber. Since the internal volume of the chamber must be increased considerably, this increases the size of the scavenging chamber. In addition to this, an oil drop passage provided in the cylinder block for guiding the lubricating oil in the cylinder head at the top of the cylinder block to the oil pan at the bottom of the cylinder block, the oil drop passage being the scavenging air. In order not to impair the flow of intake air in the room, it must be configured to be arranged outside the scavenging chamber. In other words, the configuration of the prior art leads to an increase in the size of the scavenging chamber. In addition to this, an oil drop passage is provided outside the scavenging chamber, which increases the size of the cylinder block, which in turn increases the overall size of the internal combustion engine and increases the weight. There was a problem. Disclosure of the invention An object of the present invention is to provide a two-cycle multi-cylinder internal combustion engine that solves this problem. In order to achieve this technical problem, claim 1 of the present invention provides:

“Multiple cylinders arranged in the first direction, and each cylinder has multiple scavenging ports in its circumferential direction.

A scavenging chamber in communication with the plurality of scavenging ports of each cylinder;

In a cylinder block having a scavenging inlet for introducing scavenging air from a scavenging pump into the scavenging chamber,

The scavenging chamber is opposed to each other across the plurality of cylinders, and includes a first scavenging chamber and a second scavenging chamber extending in a first direction,

The scavenging inlet is provided at an end portion in the first direction of the cylinder block, and communicates with the first scavenging chamber and the second scavenging chamber via a branch portion, respectively, and the plurality of cylinders and the branch portion are connected to each other. An oil dropping passage extending in the second direction perpendicular to the first direction is provided in between. It is characterized by that. Further, claim 2 of the present invention is

“In the description of claim 1, further comprising a cylinder head at the top and an oil pan at the bottom, and an output mission case is joined to the end in the first direction.” It is characterized by that. Further, claim 3 of the present invention is

“A two-cycle multi-cylinder internal combustion engine comprising: a cylinder block according to claim 2; and a retainer for supporting an oil seal with respect to a crankshaft, provided in a part of the transmission case. Retainer An oil passage is provided so as to bypass the rank shaft, and the oil dropping passage communicates with the oil pan through the oil passage. ". Further, claim 4 of the present invention is

“The two-stroke multi-cylinder internal combustion engine according to claim 3, wherein the scavenging inlet provided at the end portion in the first direction is integrated with an upper portion of the transmission case so as to protrude from the end portion. It is featured in that. Further, claim 5 of the present invention provides

“A two-cycle multi-cylinder internal combustion engine according to claim 3, wherein the two-cycle multi-cylinder internal combustion engine is a unit type.” In this configuration, the intake air (scavenging) from the scavenging pump first reaches the scavenging inlet and is branched and distributed from the scavenging inlet to both scavenging chambers. Branching toward both scavenging chambers extending in one direction, and flowing in both scavenging chambers in the direction of the crankshaft, is distributed to each scavenging port in each cylinder. On the other hand, the lubricating oil in the cylinder head is returned to the oil pan through the oil passage provided in the retainer from the oil dropping passage provided in the cylinder block. In this case, a scavenging chamber for each scavenging point in each cylinder is formed in two scavenging chambers extending in the crankshaft direction on both the left and right sides of the row in each cylinder, while the scavenging inlet is provided in the cylinder block. It is provided at one of the two ends in the direction of the crank axis, and this scavenging inlet is branched to communicate with both scavenging chambers, so that intake air from one scavenging inlet is sent to each cylinder. Since each scavenging port can be evenly distributed through two scavenging chambers extending in the direction of the cylinder row, the internal volume in the scavenging chamber can be reduced as compared with the prior art. In addition, since the oil drop passage from the cylinder head is arranged inside the branch portion from the scavenging inlet to both scavenging chambers, the space inside the branch portion can be used for forming the oil drop passage. Thus, in combination with the reduction of the internal volume in the scavenging chamber, the cylinder block can be made smaller and lighter, and thus the overall internal combustion engine can be made smaller and lighter. On the other hand, the lower end of the oil drop passage is located in the transmission case, and the lower end communicates with the oil pan through an oil passage provided in the retainer so as to bypass the crankshaft. Since it is possible to avoid opening an oil drop passage at the output end face of the cylinder block where the transmission case is joined, the lubricating oil in the cylinder head should be returned to the oil pan while bypassing the crankshaft. Therefore, it is possible to reliably prevent the strength at the joint portion of the output mission case with respect to the cylinder opening from being lowered. In particular, the scavenging inlet is integrated into the upper end of the mission case on one end face on the output side of the cylinder block so as to protrude from the one end face. Since the scavenging inlet can overlap with the mission case in the crankshaft direction, the internal combustion engine can be reduced in size. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway side view showing an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

FIG. 3 is a cross-sectional view taken along the line I I I -I I I of FIG.

FIG. 4 is a sectional view taken along line IV-IV in FIG. BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. 1 to 4 showing the case where the embodiment of the present invention is applied to a unitary type two-cycle internal combustion engine having two cylinders. This will be explained. In these figures, reference numeral 1 denotes a cylinder block. The cylinder block 1 has a cylinder head 2 force on its upper surface and an oil van 3 on its lower surface. Inside the cylinder block 1, two cylinders 4 are arranged side by side in the axial direction of the crankshaft 5, and each cylinder 4 contains a piston 6 that reciprocates in conjunction with the rotation of the crankshaft 5. In addition, Each cylinder 4 is provided with scavenging ports 7 that are opened and closed by reciprocating movement of the piston 6 inside the cylinder 4 at a plurality of positions in the circumferential direction. Further, inside the cylinder block 1, two scavenging chambers 8 and 9 extending in the direction of the crankshaft 5 are formed on the left and right sides of the row in each cylinder 4, and the cooling water jacket 10 is It is formed so as to surround each cylinder 4. A mission case 11 with a built-in output mission (not shown) is fastened to the output side end face 1 a of the left and right end faces in the direction of the crankshaft 5 in the cylinder block 1. A retainer 13 that supports an oil seal 12 fitted to the crankshaft 5 is joined to a portion of the side end face 1 a in the transmission case 11. An inlet header 14 is integrally provided on the output side end face 1 a of the cylinder block 1 above the transmission case 11 1 so as to protrude from the end face 1 a. A scavenging inlet 15 from a scavenging pump (not shown) is provided on the upper surface of the inlet header 14, and the inlet header 14 is connected to one of the scavenging chambers 8 and 9 as shown in plan view of FIG. Bifurcated into a communication path 14a to the other scavenging chamber 8 and a communication path 14b to the other scavenging chamber 9. A valve mechanism chamber (not shown) in the upper surface of the cylinder head 2 inside the portion of the cylinder block 1 that branches from the inlet header 14 to the both communication passages 14 a, 14 b The oil drop passage 1 6 from the An oil passage 1 is formed so as to extend in the vertical direction, and its lower end 16 a is located in the mission case 11 1, while the retainer 13 is extended to bypass the crankshaft 5. 7 is provided so that the oil dropping passage 16 communicates with the oil pan 3 through the oil passage 17. In this configuration, intake air (scavenging) from the scavenging pump first reaches the inlet header 14 from the scavenging inlet 15, and then enters both scavenging chambers 8, 9 extending in the crankshaft direction on both the left and right sides of the cylinder row. The gas flows into the two scavenging chambers 8 and 9 in the direction of the crankshaft, and is distributed to each scavenging port 7 in each cylinder 4. On the other hand, the lubricating oil in the valve mechanism in the front cylinder head 2 is returned to the oil pan 3 from the oil drop passage 16 provided in the cylinder block 1 through the oil passage 17 provided in the retainer 13. In this case, a scavenging chamber for each scavenging port 7 in each cylinder 4 is formed in two scavenging chambers 8 and 9 extending in the crankshaft direction on both the left and right sides of the row in each cylinder, while the scavenging inlet 15 is By providing the cylinder block 1 at one of the ends in the crank axis direction and branching the scavenging inlet 15 to communicate with the scavenging chambers 8 and 9, one scavenging The intake air from the inlet 15 can be evenly distributed to each scavenging port 7 in each cylinder 4 through two scavenging chambers 8 and 9 extending in the direction of the cylinder row. Further, the oil drop passage 16 from the valve mechanism chamber in the cylinder head 2 is disposed inside the branch portion from the scavenging inlet 15 to both the scavenging chambers 8 and 9, so that the branch portion The wasted space inside can be used to form the oil drop passage 16. Furthermore, the lower end 16 a of the oil drop passage 16 is located in the mission case 11, and the lower end 16 a is provided so as to bypass the crankshaft 5 in the retainer 13. By communicating with the oil pan 3 through the oil passage 17, an oil dropping passage is opened at a portion of the output side end face 1 a of the cylinder block 1 where the transmission case 11 is joined. It can be avoided. In addition, an inlet header 14 with a scavenging inlet 15 is projected from the end face 1 a to the upper part of the mission case 1 1 in the output end face 1 a of the cylinder block 1. As a result, the inlet header 14 having the scavenging inlet 15 can overlap the mission case 11 in the crankshaft direction. Although the present embodiment is a case of a Uniflow type two-cycle internal combustion engine in which only the scavenging port 7 is provided for the cylinder 4, the present invention is not limited to this and the scavenging is performed for the cylinder. Needless to say, the present invention can be applied to a two-cycle internal combustion engine of a loop or a cross flow type in which an exhaust port is provided in addition to a port. Industrial applicability

Cylinder head of the present invention and two-cycle multi-cylinder internal combustion engine equipped with the same Seki has an oil drop passage from the cylinder head disposed inside the branch from the scavenging inlet to both scavenging chambers, so that the space inside the branch can be used to form an oil drop passage. Therefore, in combination with the reduction of the internal volume in the scavenging chamber, the cylinder block can be made smaller and lighter, and thus the overall internal combustion engine can be made smaller and lighter.

Claims

The scope of the claims

1. A plurality of cylinders arranged in the first direction, and each cylinder has a plurality of scavenging ports in its circumferential direction,

A scavenging chamber communicating with the plurality of scavenging ports of each cylinder;

The scavenging inlet is provided at an end portion in the first direction of the cylinder block, and communicates with the first scavenging chamber and the second scavenging chamber via a branch portion, respectively, and the plurality of cylinders and the branch portion are connected to each other. A cylinder block having an oil dropping passage extending in the second direction perpendicular to the first direction.

2. The cylinder block according to claim 1, further comprising a cylinder head at the top and an oil pan at the bottom, wherein the output transmission case is joined to the end in the first direction.

3. A two-cycle multi-cylinder internal combustion engine comprising a cylinder block according to claim 2 and a retainer for supporting an oil seal with respect to a crankshaft provided in a part of the mission case. An oil passage is provided in the retainer so as to bypass the crankshaft, and the oil dropping passage communicates with an oil pan through the oil passage.

4. The two-cycle multi-cylinder of claim 3, wherein the scavenging inlet provided at the end portion in the first direction is integrally provided at an upper portion of the mission case so as to protrude from the end portion. Internal combustion engine.

5. The two-cycle multi-cylinder internal combustion engine according to claim 3, wherein the two-cycle multi-cylinder internal combustion engine is a Uniflow type.