JP2006283594A - Breather device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent intrusion of blow-by gas into a plug hole with eliminating a joining surface by not requiring separation of a breather chamber into a cylinder head side and a head cover side, and simplifying a structure of a breather chamber, without separation of a plug hole wall. <P>SOLUTION: A plurality of spark plugs are provided between a pair of camshafts along a cylinder row direction. The plug hole wall enclosing the spark plug is projected on an inner surface of a head cover covering a cylinder head. The breather chamber is defined in the head cover by a lower part bulkhead abutting on a lower end of the plug hole wall. In a breather device for the engine dividing the breather chamber in a box shape extending in the cylinder row direction by providing ribs traversing in the head cover with connecting the plug hole walls, step parts forming a same level surface are formed on the plug hole wall, the rib and the head cover, and the breather chamber is divided into a lower part breather chamber and an upper part breather chamber by attaching inner bulkhead on the stepped parts. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a breather device for an engine, and in particular, when forming a breather chamber that overlaps vertically, there is no need to divide the breather chamber into a cylinder head side and a head cover side, and the structure of the breather chamber is simplified by eliminating the need for a joint surface. Further, the present invention relates to an engine breather device that eliminates the possibility of blow-by gas entering the plug hole without dividing the plug hole wall.

  The engine includes a cylinder block, a cylinder head attached to the upper part of the cylinder block, a head cover attached to the upper part of the cylinder head, and an oil pan attached to the lower part of the cylinder block.

  A crankshaft is rotatably supported in a lower portion of a bore hole formed in the cylinder block, and a piston is slidably inserted into the bore hole, and is inserted into a pin hole formed in the piston. The piston pin and the crank pin of the crankshaft are connected by a connecting rod to form a combustion chamber on the lower surface of the cylinder head.

  At this time, a breather chamber is provided in the head cover that covers the cylinder head of the engine to promote gas-liquid separation of blow-by gas.

Japanese Patent Laid-Open No. 5-86832 JP 2001-12227 A

  In the conventional engine breather apparatus, the engine 102 is attached to a cylinder block (not shown), a cylinder head 106 attached to the upper part of the cylinder block, and an upper part of the cylinder head 106, as shown in FIG. A head cover (also referred to as “cylinder head cover”) 108 and an oil pan (not shown) attached to the lower part of the cylinder block are provided.

  The engine 102 communicates with the combustion chamber 107, a crankshaft (not shown) rotatably supported at the lower portion of the cylinder block, a combustion chamber 107 formed on the lower surface of the cylinder head 106, and the combustion chamber 107. The intake port 109 and the exhaust port 111 are provided, and the valve operating mechanism 114 is configured to open and close the intake port 109 and the exhaust port 111.

  At this time, the combustion chamber 107 is slidably inserted into an inner peripheral surface of a cylinder sleeve (not shown) that is attached to an inner peripheral portion of the cylinder block and exposes a bore hole (not shown) and the bore hole. The top surface of the piston (not shown) and the lower surface of the cylinder head 106 are formed.

  The valve operating mechanism 114 includes an intake side camshaft 116, an exhaust side camshaft 118, an intake side cam 120 provided on the intake side camshaft 116, and an exhaust side cam 122 provided on the exhaust side camshaft 118. And an intake valve 113 for opening and closing the intake port 109 and an exhaust valve 115 for opening and closing the exhaust port 111.

  Further, a plurality of spark plugs (not shown) are provided along the cylinder row direction between the intake side camshaft 116 and the exhaust side camshaft 118 which are a pair of camshafts supported by the cylinder head 106. Then, a plug hole wall 124 surrounding the spark plug is protruded from the inner surface 108 f of the head cover 108 covering the cylinder head 106.

  Then, as shown in FIG. 6, a breather chamber 128 is defined in the head cover 108 by a lower partition wall 126 that abuts against the lower end of the plug hole wall 124, and communicates between the plug hole walls 124 so that the inside of the head cover 108. The breather chamber 128 is divided into a box shape extending in the cylinder row direction by providing a rib 130 for longitudinally cutting the rib 130.

  That is, the breather chamber 128 communicates with an air cleaner (not shown) through a rib 130, communicates with a main side (right side in FIGS. 6 and 7) located mainly on the exhaust side, a PCV valve (not shown), and intake air. The flow of blow-by gas in the main side first breather chamber 128A is disclosed by a thick solid line because it is divided into a box extending in the cylinder row direction on the PCV valve side (left side in FIGS. 6 and 7) located on the side The flow of blow-by gas in the PCV valve side second breather chamber 128B is disclosed by a thick broken line.

  As shown in FIG. 7, the lower partition 126 has an inlet 136 through which blow-by gas flows from the intake side camshaft 116 and exhaust side camshaft 118 side (also referred to as “cam chamber side”) to the breather chamber 128 side. Form.

  At this time, as shown in FIG. 7, the inlet portion 136 supplies a blow-by gas to the main-side inlet portion 136 a through which blow-by gas flows to the main-side first breather chamber 128 A side and the PCV valve-side second breather chamber 128 B side. The main side inlet portion 136a is formed in the vicinity of the plug hole wall 124 and in the central upper portion in FIG. 7, and the PCV valve side inlet portion 136b is connected to the plug side wall 136b. It is formed in the vicinity of the hole wall 124 and in the central portion in FIG.

  Furthermore, an outlet 140 for discharging blow-by gas from the breather chamber 128 side is formed on the inner surface 108f of the head cover 108.

  At this time, as shown in FIG. 7, the outlet portion 140 includes a main side outlet portion 140a for discharging blowby gas from the main side first breather chamber 128A side, and a blowby gas from the PCV valve side second breather chamber 128B side. The PCV valve side outlet part 140b is formed in the lower left part in FIG. 7, and the PCV valve side outlet part 140b is formed in the upper left part in FIG. The

  The breather chamber reduces the outflow of oil in blowby gas from the head cover.

However, the conventional engine breather device has the following problems.
(1) The breather chamber has a one-story structure separated by the intake chamber camshaft and the exhaust chamber camshaft and the lower partition wall assembled to the head cover.
As a result, the blow-by gas passage in the breather chamber cannot be lengthened, and the amount of oil flowing out of the breather chamber is increased.
(2) The lower partition wall is provided with an oil drop hole (see reference numeral 148 in FIG. 7) for dropping the engine oil accumulated in the breather chamber to the cam chamber side which is the intake side camshaft and exhaust side camshaft side. The oil pit and the cam chamber are directly connected.
As a result, the oil agitated by the intake side camshaft and the exhaust side camshaft directly flows into the breather chamber from the cam chamber, and the amount of oil outflow increases.
(3) Further, there can be considered a measure for reducing the amount of oil outflow from the breather chamber by multilayering the breather chamber. However, such a measure has a disadvantage that the structure of the breather chamber is complicated.

  That is, in the above (3), when the breather chamber formed in the head cover is divided vertically by the internal partition made of a plate or the like, a member such as a cam cap fixed to the cylinder head and the head cover are respectively provided. Since the concave portions facing each other are formed and the inner partition wall serving also as a sealing member is sandwiched between the concave portions and joined, there is a disadvantage that the joining surface increases and the structure of the breather chamber becomes complicated.

  In addition, when the breather chamber having the plug hole wall is divided as described above, a fastening point is provided at the outer peripheral portion of the joint surface so that blow-by gas does not leak into the plug hole from the split surface of the plug hole wall. There is a problem that the structure becomes complicated because it is required to be provided.

  Therefore, in order to eliminate the above-described disadvantages, the present invention provides a head cover that covers a plurality of spark plugs along a cylinder row direction between a pair of camshafts that are pivotally supported by the cylinder head. A plug hole wall that surrounds the spark plug protrudes on the inner surface of the head cover, and a breather chamber is defined in the head cover by a lower partition wall that comes into contact with a lower end of the plug hole wall. In a breather device for an engine in which a rib that cuts through the inside is provided and the breather chamber is divided into a box shape extending in the cylinder row direction, a stepped portion that is flush with the plug hole wall, the rib, and the head cover is formed. An internal partition is attached to the step portion, and the breather chamber is divided into a lower breather chamber and an upper breather chamber.

  As described above in detail, according to the present invention, a plurality of spark plugs are disposed along the cylinder row direction between a pair of camshafts that are pivotally supported by the cylinder head, and the inner surface of the head cover that covers the cylinder head. The plug hole wall that surrounds the spark plug protrudes into the head cover with a lower partition wall that abuts the lower end of the plug hole wall, and a rib that communicates between the plug hole walls and runs vertically through the head cover. In a breather device for an engine in which a breather chamber is provided and is divided into a box shape extending in the cylinder row direction, a stepped portion is formed on the plug hole wall, the rib, and the head cover, and an inner partition is attached to the stepped portion. Is divided into a lower breather chamber and an upper breather chamber, the breather chamber must be divided into a cylinder head side and a head cover side. The structure of the breather chamber can be simplified by eliminating the need for a joining surface, and the plug hole wall is not divided, so there is no possibility of blow-by gas entering the plug hole, which is practically advantageous. It is.

  By inventing as described above, it is not necessary to divide the breather chamber into the cylinder head side and the head cover side, the joint surface is unnecessary, the structure of the breather chamber is simplified, and the plug hole wall is divided. This eliminates the risk of blow-by gas entering the plug hole.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  1 to 5 show an embodiment of the present invention. In FIG. 2, 2 is an engine.

  The engine 2 includes a cylinder block 4, a cylinder head 6 attached to the top of the cylinder block 4, a head cover (also referred to as “cylinder head cover”) 8 attached to the top of the cylinder head 6, And an oil pan 10 attached to the lower portion.

  The engine 2 includes a crankshaft 12 rotatably supported at the lower portion of the cylinder block 4, a combustion chamber (not shown) formed on the lower surface of the cylinder head 6, and the combustion chamber (see FIG. An intake port and an exhaust port (not shown) communicating with each other (not shown) and a valve mechanism 14 for opening and closing the intake port and the exhaust port are provided.

  At this time, the combustion chamber is slidably inserted into an inner peripheral surface of a cylinder sleeve (not shown) that is mounted on the inner peripheral portion of the cylinder block 4 and exposes a bore hole (not shown) and the bore hole. The top surface of the piston (not shown) and the lower surface of the cylinder head 6 are formed.

  The valve mechanism 14 includes an intake camshaft 16, an exhaust camshaft 18, an intake cam 20 provided on the intake camshaft 16, and an exhaust cam 22 provided on the exhaust camshaft 18. And an intake valve (not shown) for opening and closing the intake port and an exhaust valve (not shown) for opening and closing the exhaust port.

  Further, a plurality of spark plugs (not shown) are disposed along the cylinder row direction between the intake side camshaft 16 and the exhaust side camshaft 18 which are a pair of camshafts pivotally supported by the cylinder head 6. Then, as shown in FIGS. 4 and 5, a plug hole wall 24 surrounding the spark plug is protruded from the inner surface 8 f of the head cover 8 covering the cylinder head 6.

  As shown in FIGS. 1 and 3, a breather chamber 28 is defined in the head cover 8 by a lower partition wall 26 that contacts the lower end of the plug hole wall 24. A rib 30 that cuts the inside of the head cover 8 is provided, and the breather chamber 28 is divided and provided in a box shape extending in the cylinder row direction.

  That is, the breather chamber 28 communicates with an air cleaner (not shown) through a rib 30 and communicates with a main side (right side in FIG. 3) mainly located on the exhaust side, a PCV valve 46 described later, and on the intake side. Since it is divided into a box extending in the cylinder row direction to the PCV valve side (left side in FIG. 3), the flow of blow-by gas in the main side first breather chamber 28A is disclosed by a thick solid line, and the PCV valve side The flow of blow-by gas in the second breather chamber 28B is disclosed by a thick broken line.

  At this time, the plug hole wall 24, the rib 30 and the head cover 8 are formed with a stepped portion 32, and an inner partition wall 34 is attached to the stepped portion 32 so that the breather chamber 28 is replaced with the lower breather chamber 28-1. And the upper breather chamber 28-2.

  That is, the breather chamber 28 having the plug hole wall 24 therein is formed into a two-layer structure with a simple structure to improve the separation performance of the oil mist contained in the blow-by gas.

  More specifically, the breather chamber 28 is divided into a main-side first breather chamber 28A and a PCV valve-side second breather chamber 28B, and therefore the lower and upper breather chambers 28-1 and 28B are separated by the internal partition wall 34. 28-2, the lower main side first breather chamber 28A-1 and the lower PCV valve side second breather chamber 28B-1, and the upper main side first breather chamber 28A-2 and the upper PCV valve side. It is divided into a total of four with the second breather chamber 28B-2.

  The step 32 includes a first step 32-1 of the plug hole wall 24, a second step 32-2 of the rib 30, and a third step of the inner surface 8 f of the head cover 8. 32-3, and the first to third step portions 32-1, 32-2, and 32-3 are attached to the internal partition wall 34 that is flush with each other. The caulking positions are 8 positions from K1 to K8 in FIG.

  Further, as shown in FIGS. 3 and 4, the lower partition wall 26 has a lower breather chamber of the breather chamber 28 from the intake side camshaft 16 and exhaust side camshaft 18 side (also referred to as “cam chamber side”). An inlet 36 for flowing blow-by gas to the 28-1 side is formed.

  At this time, as shown in FIGS. 3 and 4, the inlet portion 36 includes a main side inlet portion 36a for flowing blow-by gas to the lower main side first breather chamber 28A-1 side, and the lower PCV valve side second breather. It consists of the PCV valve side inlet part 36b which flows blow-by gas to the chamber 28B-1 side.

  Further, the internal partition wall 34 is formed with a communication portion 38 that functions as an inlet portion for flowing blow-by gas from the lower breather chamber 28-1 side to the upper breather chamber 28-2 side of the breather chamber 28.

  At this time, as shown in FIGS. 3 and 4, the communication part 38 includes a main side communication part 38a for flowing blow-by gas to the upper main side first breather chamber 28A-2 side, and the upper PCV valve side second breather. It consists of the PCV valve side communication part 38b which flows blow-by gas to the chamber 28B-2 side.

  Furthermore, an outlet 40 for discharging blow-by gas from the upper breather chamber 28-2 side of the breather chamber 28 is formed on the inner surface 8f of the head cover 8.

  At this time, as shown in FIGS. 1, 3, and 4, the outlet portion 40 includes a main side outlet portion 40 a that discharges blow-by gas from the upper main side first breather chamber 28 </ b> A- 2 side, and the upper PCV valve. It comprises a PCV valve side outlet 40b for discharging blow-by gas from the side second breather chamber 28B-2 side.

  An inlet portion 36 to the lower breather chamber 28-1 and an outlet portion 40 from the upper breather chamber 28-2 are provided at positions close to each other in the cylinder row direction, and the lower breather chamber 28-1 and the upper breather A communication portion 38 for communicating the chamber 28-2 is provided at a position away from the inlet portion 36 and the outlet portion 40 in the cylinder row direction.

  That is, the main side inlet portion 36a and the PCV valve side inlet portion 36b, which are the inlet portions 36, are provided above the cam cap 42 that covers the upper half of the intake side camshaft 16, as shown in FIG. As shown in FIG. 3, the main side outlet 40a, which is the outlet 40, is formed on the PCV valve side of the head cover 8, that is, on the lower side of the left side surface in FIG. 3, and the PCV valve side outlet 40b is formed on the head cover. 8 on the PCV valve side, that is, in the vicinity of the upper part on the left side surface in FIG. 3, and the inlet portion 36 and the outlet portion 40 are provided at positions close to each other in the cylinder row direction.

  Further, as shown in FIG. 3, the main side communication portion 38a of the communication portion 38 is formed on the main side of the head cover 8, that is, in the vicinity of the upper portion on the right side surface in FIG. 8 on the PCV valve side, that is, in the vicinity of the lower part of the left side surface in FIG.

  Reference numeral 44 is a surge tank, 46 is a PCV valve, and 48 is an oil pit.

  Next, the operation will be described.

  Explaining the flow of blow-by gas on the main side of the breather chamber 28, blow-by gas swept up by the intake-side camshaft 16 and the exhaust-side camshaft 18 passes through the main-side inlet portion 36a of the lower partition wall 26, The air flows from the intake chamber camshaft 16 and the exhaust camshaft 18 to the lower main side first breather chamber 28A-1 side of the breather chamber 28.

  The blow-by gas that has flowed into the lower main side first breather chamber 28A-1 flows from the lower left part of FIG. 3 to the lower right part of FIG. 3, as shown by the thick solid line in FIG. It flows from the lower right part to the upper right part of FIG.

  The blow-by gas flowing into the upper main side first breather chamber 28A-2 flows from the upper right part of FIG. 3 to the lower right part of FIG. 3 as shown by the thick solid line in FIG. It flows from the part to the lower left part of FIG. 3 and flows to the air cleaner side (not shown) through the main side outlet 40a formed in the head cover 8.

  The flow of the blow-by gas on the PCV valve side of the breather chamber 28 will be described. The blow-by gas lifted up by the intake-side camshaft 16 and the exhaust-side camshaft 18 is the inlet portion of the lower partition wall 26 on the PCV valve side. The air flows from the cam chamber side, which is the intake side camshaft 16 and the exhaust side camshaft 18 side, to the lower PCV valve side second breather chamber 28B-1 side of the breather chamber 28 via 36b.

  The blow-by gas that has flowed into the second PCV valve side second breather chamber 28B-1 flows from the upper left part of FIG. 3 to the lower left part of FIG. 3, as shown by the thick broken line in FIG. It flows through the PCV valve side communication part 38b formed in the upper part 34 of the breather chamber 28 to the second PCV valve side second breather chamber 28B-2 side.

  The blow-by gas that has flowed into the second breather chamber 28B-2 on the upper PCV valve side flows from the lower left part of FIG. 3 to the upper left part of FIG. 3 as shown by the thick broken line in FIG. It flows to the PCV valve 46 side through the PCV valve side outlet 40b.

  As a result, a stepped portion 32 that is flush with the plug hole wall 24, the rib 30, and the head cover 8 is formed, and an internal partition wall 34 is attached to the stepped portion 32 to replace the breather chamber 28 with the lower breather chamber 28-1. And the upper breather chamber 28-2, it is unnecessary to divide the breather chamber 28 into the cylinder head 6 side and the head cover 8 side, and the structure of the breather chamber 28 is simplified by eliminating the need for a joint surface. In addition, since the plug hole wall 24 is not divided, there is no possibility of blow-by gas entering the plug hole, which is practically advantageous.

  In addition, an inlet portion 36 to the lower breather chamber 28-1 and an outlet portion 40 from the upper breather chamber 28-2 are provided at positions adjacent to each other in the cylinder row direction, and the lower breather chamber 28-1 and the upper breather are provided. The passage length of the breather chamber 28 divided in a box shape extending in the cylinder row direction is provided by providing the communication portion 38 for communicating the chamber 28-2 at a position away from the inlet portion 36 and the outlet portion 40 in the cylinder row direction. The oil mist separation effect can be enhanced by extending the maximum.

  Furthermore, the main side inlet portion 36a and the PCV valve side inlet portion 36b, which are the inlet portions 36, are provided above the cam cap 42 that covers the upper half of the intake side camshaft 16 (36). The oil mist scattered by the centrifugal force of the intake camshaft 16 (36) can be prevented from entering the breather chamber 28.

  The present invention is not limited to the above-described embodiments, and various application modifications are possible.

  For example, in an embodiment of the present invention, an inlet for flowing blow-by gas from the intake side camshaft and exhaust side camshaft side (also referred to as “cam chamber side”) to the lower breather chamber side of the breather chamber, The structure formed in the lower partition wall, or the communication section functioning as an inlet portion for flowing blow-by gas from the lower breather chamber side to the upper breather chamber side of the breather chamber is formed in the inner partition wall. It is also possible to have a special configuration in which the passage length of the breather chamber divided into a box shape extending in the direction is further extended to enhance the oil mist separation effect.

  That is, when the inlet part is formed in the lower partition wall or the communication part is formed in the inner partition wall, the flow direction of the blow-by gas is restricted to at least one of the inflow side surface part and the outflow side surface part of the inlet part and the communication part. And the protrusion part which has a baffle plate function which makes the passage length of a breather chamber large is provided.

  In this case, the flow direction of the blow-by gas is regulated by the protrusions, the passage length of the breather chamber can be increased, and the oil mist separation effect can be enhanced.

It is an expanded sectional view by the II line of FIG. 3 of the breather apparatus of the engine which shows the Example of this invention. It is a schematic diagram of an engine. It is a bottom view of a head cover. It is a top view of a cylinder head. FIG. 5 is a cross-sectional bottom view of the head cover taken along line VV in FIG. 1. It is sectional drawing of the cylinder head and head cover part of the engine which show the prior art of this invention. It is a bottom view of a head cover.

Explanation of symbols

2 Engine 4 Cylinder block 6 Cylinder head 8 Head cover (also referred to as “cylinder head cover”)
8f Inner surface 10 Oil pan 12 Crankshaft 14 Valve mechanism 16 Intake side camshaft 18 Exhaust side camshaft 20 Intake side cam 22 Exhaust side cam 24 Plug hole wall 26 Lower partition wall 28 Breather chamber 28A Main side first breather chamber 28B PCV valve Side second breather chamber 28-1 Lower breather chamber 28-2 Upper breather chamber 30 Rib 32 Step part 34 Internal partition wall 36 Inlet part 36a Main side inlet part 36b PCV valve side inlet part 38 Communication part 38a Main side communication part 38b PCV valve Side communication part 40 Outlet part 40a Main side outlet part 40b PCV valve side outlet part 42 Cam cap 44 Surge tank 46 PCV valve 48 Oil pit

Claims (3)

  A plurality of spark plugs are disposed along a cylinder row direction between a pair of camshafts that are pivotally supported by the cylinder head, and a plug hole wall that surrounds the spark plug protrudes from the inner surface of the head cover that covers the cylinder head. The breather chamber is defined in the head cover by a lower partition wall that abuts the lower end of the plug hole wall, and a rib is provided to communicate between the plug hole walls and to cut the inside of the head cover. A breather device for an engine divided into a box extending in a direction, wherein the plug hole wall, the rib, and the head cover are formed with a stepped portion, and an inner partition is attached to the stepped portion to form the breather chamber as a lower breather. A breather device for an engine, which is divided into a chamber and an upper breather chamber.   An inlet portion to the lower breather chamber and an outlet portion from the upper breather chamber are provided at positions close to each other in the cylinder row direction, and a communication portion for communicating the lower breather chamber and the upper breather chamber is provided in the cylinder row direction. The breather device for an engine according to claim 1, wherein the breather device is provided at a position away from the outlet and the outlet.   The breather device for an engine according to claim 2, wherein the inlet portion is positioned above a cam cap that covers an upper half portion of the camshaft.

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