JP2006177258A - Engine head cover structure - Google Patents

Abstract

The present invention is an engine in which a cylinder head is inclined and installed so that oil is easily collected in a head cover, and an oil separation chamber is utilized by maximizing the use of a lateral inlet opening and a protruding bottom wall structure. The engine head cover structure prevents oil from being sucked into the blow-by gas inlet from the outer surface of the head cover and the ceiling surface of the head cover.
The present invention relates to an inlet opening formed in a blowby gas inlet portion of an oil separation chamber formed in a head cover at a lowermost side wall on a lower side in a tilt direction of a cylinder head, and the inlet. The eaves portion 22 is provided only on the lower wall portion around the opening 21. Thereby, the oil in the head cover 5 can be prevented from being sucked from the inlet opening 21. In particular, since the eaves portion 22 is only around the inlet opening 21, little oil is received from the outer surface of the oil separation chamber 11 and the ceiling surface of the head cover 5 received by the eaves portion 22, and this is also sucked from the inlet opening 21. Oil can be suppressed.
[Selection] Figure 3

Description

  The present invention relates to an engine head cover structure that is mounted on a vehicle body with an inclination about an axis of an output shaft.

  The shape of the engine room of an automobile (vehicle) equipped with a reciprocating engine (an engine that outputs torque from the reciprocating motion of a piston) varies greatly depending on the design. Therefore, in an automobile, the entire engine body is tilted around the axis of the crankshaft (output shaft) and mounted on the vehicle body in response to the requirement to store the reciprocating engine in an engine room having a restricted shape. Yes.

  By the way, in a reciprocating engine, as a process of blow-by gas containing oil, usually inside a head cover that is assembled so as to cover the upper side of a cylinder head (an engine part with a combustion chamber, a spark plug, and a valve operating system) A structure in which an oil separation chamber (which constitutes an oil separator) is provided is used. Most of the main body of the head cover forms an oil separation chamber on the inner side of the cover portion that covers the camshaft where the cylinder head is assembled, and conforms to the shape of the cover portion. In addition, a blow-by gas inlet portion (portion for introducing the blow-by gas from inside the head cover) is formed, and an oil return portion (portion for returning the oil separated in the oil separation chamber into the head cover) on the other end side of the oil separation chamber; A structure is used in which a blow-by gas outlet part (a part for returning the gas separated in the oil separation chamber to the intake system of the engine) is used. With this structure, blow-by gas in the head cover is introduced into the oil separation chamber from the blow-by gas inlet using the negative pressure of the intake system (or the flow of intake air). Then, while the blow-by gas is recirculated from the blow-by gas outlet to the intake of the engine, the oil component is separated from the gas, and the separated oil flows out from the oil return part into the head cover and again into the oil pan. It is intended to be collected.

  In the blow-by gas inlet portion of such a blow-by gas separation structure, a structure in which a plurality of through holes are formed in the bottom wall of the oil separation chamber is usually used. The inlet portion having such a hole structure is also used for the engine mounted at an inclination described above.

  However, in the case of an engine installed at an inclination, there is a problem in terms of the treatment of oil splashes generated by lubrication of the valve train.

  That is, because the blow-by gas inlet portion opens directly above (or around) the camshaft, the splash of oil that lubricates the valve system in the head cover is caused by rotation of the camshaft, cams on the camshaft. It is easy to enter from the opening of the blow-by gas inlet part by the wind (dynamic pressure) brought about by the rotation.

  Here, even in the case of a horizontal engine in which a normal cylinder head is arranged vertically, even if oil splashes enter the blow-by gas inlet, there is even an entry suppression wall that blocks oil splash intrusion immediately after the inlet. If it does, it will fall from a blow-by gas inlet part, without approaching the deep part of an oil separation chamber.

  However, in the case of an engine that is installed at an inclination, the head cover is inclined in the circumferential direction of the camshaft, so that the entire oil separation chamber is inclined with respect to the circumferential direction of the camshaft. For this reason, the part arrange | positioned in a point lower than the point with a through-hole is formed in the bottom wall of an oil separation chamber. Since the lowered portion is a portion adjacent to the through hole, it is difficult to prevent the oil splash from entering the previous wall for suppressing entry. Therefore, the splash of the oil that has once entered the oil separation chamber from the through hole accumulates in the corner portion of the lower bottom wall of the oil separation chamber. Moreover, once accumulated oil is difficult to return to the outside of the oil separation chamber from the through hole.

  The oil staying in the oil separation chamber becomes fine droplets due to the vibration of the engine, and is mixed into the gas separated in the oil separation chamber, which tends to affect the oil separation performance.

  On the other hand, in the reciprocating engine, as disclosed in Patent Document 1, an inlet opening that opens laterally is formed at the bottom of the oil separation chamber as a blow-by gas inlet, and the oil separation chamber of the oil separation chamber having the inlet opening is formed. There is a structure in which the entire bottom wall is slightly extended forward.

From this Patent Document 1, when the engine is inclined along the circumferential direction of the output shaft, the lateral inlet opening makes it difficult for oil droplets in the head cover to enter the oil separation chamber, and in the oil separation chamber. It can be seen that the splash of oil that has entered does not accumulate and is led out of the oil separation chamber. Furthermore, it can be seen that the entire bottom wall protruding forward blocks the oil splash (due to a rotating camshaft or cam) sucked into the inlet opening.
Japanese Utility Model Publication No.2-16055

  However, this structure creates new problems.

  That is, during the operation of the engine, oil is scattered by rotation of the camshaft (including the cam) in the head cover, and the splashes of oil adhere to various places such as the ceiling surface and the inner surface of the head cover.

  However, the structure in which the entire bottom wall protrudes forward receives the oil that flows from the outer surface of the oil separation chamber or the ceiling surface of the head cover at the protruding portion. For this reason, due to the attraction of blow-by gas sucked from the inlet opening, a large amount of oil received at the protruding portion is guided to the inlet opening, and a large amount of oil enters the oil separation chamber together with the blow-by gas. Is likely to occur.

  Accordingly, an object of the present invention is to use the side entrance opening and the protruding bottom wall structure to the maximum extent in an engine in which the cylinder head is installed with an inclination and oil is likely to accumulate in the head cover. Another object of the present invention is to provide an engine head cover structure that can prevent oil in the head cover body from being sucked into the blow-by gas inlet.

    In order to achieve the above object, the blowby gas inlet portion of the oil separation chamber formed in the head cover is formed at the lowermost side of the side wall arranged on the lower side in the tilt direction of the cylinder head. And an eaves portion provided only in the lower wall portion around the inlet opening in the oil separation chamber.

  With this configuration, in an engine in which the cylinder head is installed with an inclination along the circumferential direction of the output shaft, the oil separation chamber is less likely to allow oil splashes to enter due to the entrance opening and the eaves that open sideways. The splash of oil that has entered the separation chamber is led out of the oil separation chamber without accumulating (not accumulating). In addition, since the eaves portion is formed only in the region where the inlet opening portion is provided, the oil sucked from the inlet opening portion is suppressed.

  In addition to the above-mentioned object, the invention according to claim 2 further provides the oil in the oil separation chamber so that the oil is led out from the oil return portion that returns favorably without impairing the performance of oil entry suppression at the blow-by gas inlet portion. The return part has an oil return opening formed at the bottom of the side wall on the lower side of the cylinder head tilt direction, and an eaves protruding from the lower wall of the oil separation chamber into the head cover so as to block the lower side of the oil return opening. The oil can be led out while blocking the wind (dynamic pressure) caused by the camshaft and cam. Further, the eaves portion of the blow-by gas inlet portion and the eave portion of the oil return portion are separated so that oil does not flow unnecessarily into the blow-by gas inlet portion.

  According to the first aspect of the present invention, the lateral inlet opening and the eaves can prevent the splash of oil scattered in the head cover from entering the oil separation chamber, and the oil that has entered Can be led out of the oil separation chamber without accumulating inside. Moreover, the eaves provided only around the inlet opening can reduce the oil from the outer surface of the oil separation chamber and the ceiling surface of the head cover received by the eaves, and can suppress the oil sucked from the inlet opening.

  Therefore, in an engine in which oil tends to stay in the head cover, for example, an engine in which a cylinder head is inclined along the circumferential direction of the output shaft, the lateral inlet opening and the eaves are utilized to the maximum. Thus, the oil can be prevented from being inadvertently sucked into the blow-by gas inlet.

  According to the second aspect of the present invention, in addition to the above effect, the oil can be led out from the oil return portion satisfactorily without impairing the effect of suppressing the oil entry at the blow-by gas inlet.

[One Embodiment]
Hereinafter, the present invention will be described based on an embodiment shown in FIGS.

  1 is a perspective view of an external appearance of a part of a reciprocating engine, FIGS. 2 and 3 are oil separation structures assembled to a head cover of the engine, and FIGS. 4 and 5 are sectional views of respective parts of the oil separation structure. Yes.

  In FIG. 1, reference numeral 1 denotes an engine body of a DOHC reciprocating engine having a plurality of cylinders, for example, three cylinders. The engine body 1 includes, for example, a cylinder block 2 having three cylinders (not shown), a cylinder head 3 mounted on the head of the cylinder block 2, an oil pan 4 assembled to the lower portion of the cylinder block 2, The head cover 5 is assembled so as to cover the upper part of the cylinder head 3. Among these, in each cylinder of the cylinder block 2, a piston (none of which is shown) is housed so as to be able to reciprocate. Each of these pistons is connected via a connecting rod (not shown) to a crankshaft 6 (only shown in FIG. 1; corresponding to an output shaft) that is rotatably supported at the lower part of the cylinder block 2.

  The cylinder head 3 is provided with an intake / exhaust valve (not shown), a combustion chamber (not shown), a fuel injection valve (not shown), and a spark plug 8 (only shown in FIG. 1) for each cylinder. is there. Further, two camshafts 9 (for intake and exhaust: only one side is shown) are rotatably supported on both sides of the cylinder head 3 as shown in FIGS. Note that all the camshafts 9 are arranged in parallel with the crankshaft 6. The camshaft 9 is driven by the output of the crankshaft 6 via a timing gear (not shown) at the end of the shaft. 3 to 5, each intake valve is driven for each cylinder by a cam 9a formed on the intake side camshaft 9, and formed on an exhaust side camshaft (not shown). Each exhaust valve is driven for each cylinder by a cam (not shown) (valve system).

  The engine body 1 has a predetermined combustion cycle (for example, an intake process, a compression process, an explosion) by operating the valve system, the fuel injection valve, and the spark plug 8 at a predetermined timing in cooperation with the reciprocation of the piston. Process and exhaust process). That is, the driving torque is output from the crankshaft 6 by the combustion cycle. While the engine body 1 is in operation, the oil collected in the oil pan 4 is pumped by an oil pump (not shown) to a place that requires lubrication, sealing, cooling or the like such as a valve operating system. It is. Of course, the blow-by gas generated in the crankcase of the cylinder block 2 (portion for accommodating the crankshaft) passes through the blow-by gas passage (not shown) formed in the cylinder block 2 and the cylinder head 3, That is, it is led out to a space surrounded by the cylinder head 3 and the head cover 5.

  Further, the mount (not shown) of the engine body 1 is structured such that the cylinder head 3 is mounted in an engine room (not shown) of an automobile (vehicle) with the cylinder head 3 tilted in the circumferential direction of the crankshaft 6 as shown in FIG. It is.

  On the other hand, in the engine body 1, for example, the cylinder block 2 is provided with a PCV valve chamber 10. Further, as shown in FIG. 1 and FIG. 3 to FIG. 5, among the head cover main body that covers the entire upper part of the cylinder block 3 of the head cover 5, the cam portion that covers the upper portion of the intake side camshaft 9 An oil separation chamber 11 (which constitutes an oil separator) for separating oil contained in blow-by gas is provided in a box-like raised portion 5 a that is elongated in the shape of the shaft 9. The oil separation chamber 11 has a structure in which the periphery is covered with a wall portion, for example, a rectangular raised portion 5a whose lower surface is opened as shown in FIGS. 2 and 3, and the lower surface of the raised portion 5a closes the opened portion. The plate member 12 assembled in this way, the end of the raised portion 5a on the timing gear side (the gear attached to one end of the camshaft) and the timing side of the plate member 12 (the gear attached to one end of the camshaft) The structure which combined the end wall part 13 which blocks | closes the open part enclosed with the edge part of is used. That is, by this structure, an elongated chamber space is formed in the region from the timing gear side to the opposite end using the internal space of the raised portion 5a. 2-5, the oil separation chamber 11 has a blow-by gas inlet 15 for introducing blow-by gas, a separation structure 16 for separating the oil, and the separated oil into the chamber space from one end side. It is formed by providing an oil return part 17 for returning and a blow-by gas outlet part 18 for leading out the gas after oil separation.

  That is, the blow-by gas inlet portion 15 is formed at one end of the chamber space, for example, at the end on the timing gear side as shown in FIG. As shown in FIGS. 2 to 4, for example, the blow-by gas inlet portion 15 has an opening formed in the side wall 20 disposed on the lower side in the inclination direction among the side walls (width direction) of the raised portion 5 a. Specifically, an inlet opening 21 (corresponding to the inlet opening) that is elongated and cut along the edge is formed at the lower end portion that is the lowermost portion of the side wall 20, thereby forming an entrance that opens sideways. is doing. As shown in FIGS. 2 to 4, in the lower portion around the inlet opening 21, for example, in the edge portion of the plate member 12, the region between both ends of the inlet opening 21 including the portion immediately below the inlet opening 21 is The eaves part 22 (equivalent to the eaves part for entrance) is formed. The eaves portion 22 is configured, for example, by protruding the edge of the plate member 12 forward. Thus, the lower side of the inlet opening 21 is blocked only by the eaves portion 22 around the inlet opening 21. That is, the eaves portion 22 has a structure that blocks the wind caused by the rotation of the camshaft 9 and the cam 9a, that is, the wind (dynamic pressure) toward the inlet opening 21. The blow-by gas inlet 15 is composed of a combination of the inlet opening 21 and the eaves 22.

  The oil separation structure 16 has a collision separation portion 24 disposed in the immediate vicinity of the inlet opening 21 as shown in FIGS. For example, a structure in which an L-shaped collision wall 25 that blocks the plate member 12 is formed on the ceiling surface portion of the raised portion 5 a that is closest to the entrance opening 21 is used for the collision separation unit 24. Specifically, the L-shaped collision wall 25 is formed of a short portion 25a protruding from the inner surface of the side wall 20 and a long portion 25b extending from the tip of the short portion 25a to the vicinity of the end wall portion 13. Yes. That is, the blow-by gas introduced from the inlet opening 21 is separated from the blow-by gas by collision with the longitudinal portion 25 b and further collision with the end wall portion 13. In addition, although not shown, a separation portion having another structure is provided in the middle of the chamber space, and in cooperation with the collision separation portion 24, the oil component is separated from the blow-by gas while the blow-by gas flows through the chamber space. The structure is

  As shown in FIGS. 2, 3, and 5, the oil return portion 17 is formed on the side wall portion of the side wall 20 opposite to the blow-by gas inlet portion 15 (the portion on the other end side of the chamber space). The same structure as the blow-by gas inlet 15 is provided. Specifically, an oil return opening 27 (corresponding to an oil return opening) formed by cutting out along the edge is formed at the lower end portion which is the lowermost portion of the side wall 20. Thus, a lateral oil return opening 27 is opened. Thus, the oil separated by the oil separation structure 16 is led out of the chamber space (inside the head cover 5) from the oil return opening 27. Of course, the derived oil returns to the oil pan 4 through oil return holes (not shown) formed in the cylinder head 3 and the cylinder block 2. However, although not shown, in the chamber space, for example, a gradient that guides the separated oil to the oil return opening 27 is formed. Further, an edge portion of the plate member 12 around the oil return opening 27, for example, an edge portion in a region between both ends of the opening 27 including immediately below the oil return opening 27, is provided with an eave portion 28 (an oil return eave portion). Equivalent) is formed. Thus, the lower side of the oil return opening 27 is blocked only by the eaves portion 28 around the opening 27. That is, the eaves portion 28 has a structure that blocks the wind caused by the rotation of the camshaft 9 and the cam 9a, that is, the wind (dynamic pressure) toward the oil return opening 27.

  As shown in FIG. 1, the blow-by gas outlet portion 18 is formed from an end portion of the raised portion 5 a opposite to the blow-by gas inlet portion 15, for example, an outlet portion 30 provided on the upper wall. The outlet portion 30 is connected to the upstream side of the throttle valve via a breather hose 31, and blow-by gas generated in the crankcase passes through the blow-by gas passages of the cylinder block 2 and the cylinder head 3 into the head cover 5. Led.

  On the other hand, as shown in FIG. 2, the blow-by gas in the head cover 5 is introduced into the oil separation chamber 11 from the inlet opening 21 (blow-by gas inlet portion 15). While this blow-by gas passes through the oil separation chamber 11, an oil component contained in the gas is separated by a collision separation unit 24 or another separation unit (not shown). Then, the separated gas is recirculated from the outlet 30 to the intake system through the breather hose 31 and used for combustion of the engine.

  The separated oil is guided along the wall surface of the oil separation chamber 11 to the oil return opening 27 (oil return portion 17). Here, the oil return opening 27 is formed laterally at the lowest point of the side wall 20 on the lower side in the tilt direction of the engine head cover 5 mounted at an inclination. As shown by the arrow a in FIG. 5, the oil X is led out from the oil separation chamber 11 without accumulating. The derived oil X is collected into the oil pan 4 through the cylinder head 3 and the oil return hole (not shown) of the cylinder block 2.

  On the other hand, two (shaft / exhaust side) camshafts 9 (only one side is shown) are rotationally driven to open and close the intake valves and exhaust valves (both not shown) of each cylinder during engine operation. (Depending on crank output). An arrow c in FIG. 4 indicates the rotation direction of the camshaft 9.

  At this time, immediately below the oil separation chamber 11, the wind (dynamic pressure) generated by the rotation of the camshaft 9 and the rotation of the cam 9a attached to the camshaft 9 as shown by the arrow b in FIGS. The oil that lubricates the internal device of the cylinder head 3 is wound up.

  Here, the blow-by gas inlet portion 15 opens sideways so as to avoid wind as shown in FIG. For this reason, the oil splash α that is wound up by the wind (shown only in FIGS. 4 and 5) is less likely to enter the blow-by gas inlet 15. Moreover, since the blow-by gas inlet 15 is inclined downward due to the inclined mounting of the engine, even if it enters, the splash of oil does not stagnate in the middle (does not accumulate) and is led out of the oil separation chamber 11. The

  Further, the eaves 22 blocks the oil splash α toward the inlet opening 21, so that the oil sucked from the inlet opening 21 is suppressed. In particular, since the eaves portion 22 is formed only in the periphery where the inlet opening 21 is provided, the eaves portion 22 receives oil flowing down the outer surface of the oil separation chamber 11 or oil falling from the ceiling surface of the head cover 5 (flowing down or the like). Oil to be dripped) is reduced, and the oil sucked together with the blow-by gas from the inlet opening 21 can be reduced.

  Therefore, in an engine in which oil tends to accumulate in the head cover, that is, an engine mounted with the cylinder head 3 tilted, the side entrance opening 21 and the eaves portion 22 are utilized to the maximum extent to be scattered in the head cover 5. It is possible to prevent inadvertent sucking of the oil that is being sucked into the blow-by gas inlet 15. In particular, the structure in which the eaves portion 22 is provided only around the entrance opening 21 is provided on both sides of the eaves portion 22 even if the space between the eaves portion 22 and the ceiling surface of the head cover 5 is blocked by oil splashes (by the cam 9a). Since a flow path from the opening portion 22a (shown only in FIG. 3) toward the inlet opening 21, and a flow path that suppresses an increase in flow path resistance, is ensured, an oil separating function of blow-by gas is ensured.

  In addition, by adopting a structure in which the oil return opening 27 and the eaves part 28 are combined in the oil return portion 17 as well, the wind (dynamic pressure) generated by the camshaft 9 (including the cam 9a) is avoided as described above. The separated oil X can be led out from the oil return opening 27 while blocking. In particular, the oil return opening 27 is inclined downward due to the inclined installation of the engine, so that the oil in the oil separation chamber 11 can be led out from the oil return opening without stagnation. In addition, since the eaves portion 28 is also disposed obliquely downward, even if a differential pressure is generated between the pressure in the oil separation chamber 11 and the pressure in the head cover 5, oil may accumulate in the oil return opening 27. Like the liquid level indicated by L in FIG. 5, the liquid level is suppressed by the thickness of the side wall 20, and there is an advantage that the amount of accumulated oil can be reduced. In addition, since the eaves portion 28 of the oil return portion 17 is separated from the eaves portion 22 of the blow-by gas inlet portion 15, the oil received by the eaves portion 22 flows into the blow-by gas inlet portion 15 and flows into the blow-by gas inlet portion 15. There is no risk of inhalation. That is, the oil can be led out from the oil return portion 17 without impairing the effect of suppressing the oil entry at the blow-by gas inlet portion 15.

  The present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention. For example, in the embodiment described above, the present invention is applied to a DOHC engine having two camshafts. However, the present invention is not limited to this, and the present invention is applied to an SOHC engine in which an intake / exhaust valve is driven by a single camshaft. May be.

The perspective view which shows a part of external shape of the engine of one Embodiment of this invention. FIG. 2 is a plan sectional view of the head cover taken along line AA in FIG. 1. The perspective view which carried out the partial cross section which shows the oil separation chamber built in the head cover, and the structure of the periphery. Sectional drawing which follows the BB line in FIG. Sectional drawing which follows the CC line | wire in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Cylinder block, 3 ... Cylinder head, 5 ... Head cover, 6 ... Crankshaft (output shaft), 11 ... Oil separation chamber, 15 ... Blow-by gas inlet part, 17 ... Oil return part, 21 ... Inlet opening (inlet opening part) ), 22 ... eaves part (inner eaves part), 27 ... oil return opening (oil return opening part), 28 ... eaves part (oil return eaves part).

Claims (2)

A head cover assembled to a cylinder head arranged to be inclined in the circumferential direction of the output shaft;
An oil separation chamber formed in the head cover and surrounded by a wall;
A blow-by gas inlet portion that is formed in the oil separation chamber and guides the blow-by gas in the head cover to the oil separation chamber;
The blow-by gas inlet is
An inlet opening formed at the bottom of the side wall disposed on the lower side of the cylinder head in the tilt direction of the oil separation chamber;
Of the lower wall of the oil separation chamber, an eaves for an inlet that is provided only in the lower wall portion around the inlet opening and protrudes inward of the head cover so as to block the lower side of the inlet opening. And a head cover structure for an engine. The oil separation chamber further includes an oil return portion for returning the oil separated in the oil separation chamber into the cover portion of the head cover at a point away from the blow-by gas inlet portion,
The oil return part is
An oil return opening formed at a lowermost portion of a side wall disposed on the lower side in the tilt direction of the cylinder head of the oil separation chamber;
An oil return eaves projecting inward from the lower wall of the oil separation chamber so as to block the lower side of the oil return opening,
The engine head cover structure according to claim 1, wherein the inlet eaves portion and the oil return eaves portion are separated from each other.

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