JP2007056811A - Oil supply structure for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply sufficient and stable hydraulic pressure to a variable valve timing mechanism 30 by a relatively simple structure in an internal combustion engine 1 having a hydraulic variable valve timing mechanism 30. <P>SOLUTION: A common oil passage 53 sucking oil in an oil reservoir part 14 by a single oil pump 51 and introducing the same to a cylinder block 3 side, and three system oil passage 54, 55, 56 independently introducing the same from the common oil passage 53 to an inside of the cylinder block 3, a valve gear 45 side in a cylinder head 2 and a variable valve timing mechanism 30 side respectively are included. An upstream end of the oil passage 55 going to the valve gear 45 side and an upstream end of the oil passage 56 going to the variable valve timing mechanism 30 side are connected to a vicinity of a connection part 59 of the common oil passage 53 and the oil passage 54 going to the inside of the cylinder block 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an oil supply structure for an internal combustion engine having a hydraulic variable valve timing mechanism.

  Some internal combustion engines are equipped with a hydraulic variable valve timing mechanism that varies the valve timing on at least one of an intake camshaft and an exhaust camshaft (see, for example, Patent Document 1).

  This variable valve timing mechanism is provided on one end side of the camshaft, and the valve timing is determined by switching the oil pressure supplied to the advance side hydraulic chamber and the retard side hydraulic chamber of the variable valve timing mechanism by an oil control valve. Is configured to change.

  In general, an internal combustion engine has an oil supply structure in which oil in an oil pan (oil storage part) provided at the bottom is pumped up by an oil pump and supplied to two systems of a cylinder block side and a cylinder head side. Is provided. The oil lubricated inside the cylinder block and the cylinder head is returned to the oil pan, so that closed-loop oil circulation is performed in the internal combustion engine.

  The cylinder block is provided with an oil passage called a main gallery, and oil is supplied from the main gallery to a crank journal, an oil jet, or the like. On the other hand, the oil supplied into the cylinder head is diverted in the cylinder head and supplied to the valve operating mechanism, the variable valve timing mechanism, and the like.

  By the way, the oil pumped up by the oil pump is supplied through a single common oil passage to the middle of the cylinder block, and is divided into an oil passage that branches into the main gallery side and the cylinder head side. Further, the flow is diverted to an oil passage that branches into the valve operating mechanism side and the variable valve timing mechanism side.

In the case of such an oil supply structure, for example, when a fluctuation in the discharge pressure of the oil pump or an oil pressure fluctuation in the oil passage toward the valve mechanism occurs in the low rotation range of the internal combustion engine, the oil pressure fluctuation is variable valve timing mechanism. The oil pressure supplied to the variable valve timing mechanism is likely to be insufficient and unstable because the oil pressure in the oil passage toward the side tends to be affected. On the other hand, it is considered to install a dedicated oil passage for supplying oil to the variable valve timing mechanism and an oil pump (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 5-86913 JP 2001-342812 A

  In the above conventional example, since the oil passage dedicated to the variable valve timing mechanism and the oil pump are provided, the equipment cost of the internal combustion engine increases, and there is a concern about an increase in weight and an increase in size.

  Although it is possible to increase the capacity of an existing oil pump without using the dedicated oil pump as described above, in such a case, the pump driving force increases at high revolutions, etc. There is a concern that friction will increase and lead to performance degradation.

  An object of the present invention is to provide a sufficient and stable hydraulic pressure to a variable valve timing mechanism with a relatively simple configuration in an oil supply structure of an internal combustion engine having a hydraulic variable valve timing mechanism.

  The present invention relates to an oil supply structure for an internal combustion engine in which at least one of an intake side camshaft and an exhaust side camshaft is provided with a hydraulic variable valve timing mechanism, and oil in an oil reservoir is supplied by a single oil pump. A common oil passage that sucks and leads to the cylinder block side, and three systems of oil passages that individually lead from the common oil passage to the inside of the cylinder block, the valve mechanism side in the cylinder head, and the variable valve timing mechanism side, respectively. The upstream end of the oil passage toward the valve mechanism and the upstream end of the oil passage toward the variable valve timing mechanism are in the vicinity of the connection portion between the oil passage toward the cylinder block and the common oil passage. It is characterized by being connected.

  According to this configuration, the configuration is simple because only a single oil pump is used to provide oil paths branched into three systems. In addition, the oil passage toward the valve mechanism and the oil passage toward the variable valve timing mechanism are separated, and the upstream ends of these oil passages are connected to the common oil passage and the cylinder block inside. Even if the oil pump discharge pressure fluctuation or the oil pressure fluctuation in the oil passage toward the valve operating mechanism occurs in the low speed range of the internal combustion engine, etc. It is suppressed or prevented that the fluctuation affects the oil pressure in the oil passage toward the variable valve timing mechanism.

  As a result, the hydraulic pressure supplied to the variable valve timing mechanism is stabilized even in a low rotation range of the internal combustion engine, and the variable valve timing mechanism can be stably operated.

  Furthermore, by connecting the oil passage toward the variable valve timing mechanism to the vicinity of the connection portion between the common oil passage and the oil passage toward the cylinder block inside, the oil passage toward the variable valve timing mechanism is provided. It becomes possible to secure as long as possible. As a result, the volume of the oil passage can be increased as much as possible, and sufficient hydraulic pressure to be supplied to the variable valve timing mechanism side can be ensured.

  Preferably, the upstream end of the oil passage toward the valve operating mechanism and the upstream end of the oil passage toward the variable valve timing mechanism are merged, and the upstream end of the merged portion is connected to the predetermined portion. be able to.

  According to this configuration, the oil passage toward the valve mechanism and the oil passage toward the variable valve timing mechanism can be installed relatively easily.

  Preferably, each of the oil passage toward the valve mechanism and the oil passage toward the variable valve timing mechanism is integrally formed on the inner surface of a timing chain cover that is detachably attached to the outside of the wall of the cylinder block. And a hole-like space surrounded by a plate attached to the groove so as to close the opening side.

  According to this configuration, when the timing chain cover is formed as a molded product, the groove can be easily obtained by transfer from a mold, for example, manufacturing is easier than in the case of making a hole in a cylinder block. In addition, the degree of freedom of the oil passage can be improved and the oil passage length can be increased.

  According to the present invention, sufficient and stable hydraulic pressure can be supplied to the variable valve timing mechanism side while maintaining a relatively simple configuration without adding an oil pump as in the conventional example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 7 show an embodiment of the present invention.

  Prior to description of the oil supply structure of the internal combustion engine according to the present invention, an internal combustion engine to which the oil supply structure is applied will be described with reference to FIG.

  FIG. 3 shows a schematic configuration of an internal combustion engine (also referred to as an engine) mounted on a vehicle such as an automobile. The internal combustion engine 1 here is, for example, a direct injection four-cylinder gasoline engine, but FIG. 3 shows only one cylinder for convenience of explanation.

  The internal combustion engine 1 shown in FIG. 3 is directly injected into the combustion chamber 5 defined by the cylinder head 2, the cylinder block 3 and the piston 4 from the intake system and the intake port 2 a and the fuel injection valve 6. The crankshaft 9 is rotated from the piston 4 through the connecting rod 8 by igniting and combusting a predetermined ratio of the air-fuel mixture comprising the fuel to be burned by the spark plug 7, and the exhaust gas after combustion is discharged. The exhaust port 2b is discharged to the exhaust system.

  The cylinder head 2 is provided with an intake valve 10 for opening and closing the intake port 2a and an exhaust valve 11 for opening and closing the exhaust port 2b, respectively, and an intake side camshaft 12 and an exhaust valve 11 for lifting the intake valve 10 An exhaust-side camshaft 13 that lifts the engine is mounted.

  As shown in FIG. 4, the intake camshaft 12 and the exhaust camshaft 13 are rotationally driven by a crankshaft 9 via a timing chain (or timing belt) 21.

  The timing chain 21 includes a timing gear 22 attached to one end of the intake camshaft 12 in the axial direction, a timing gear 23 provided at one end of the exhaust camshaft 13 in the axial direction, and one axial end of the crankshaft 9. It is wound around the timing gear 24 provided in the. The tension of the timing chain 21 is automatically adjusted by the chain tensioner 25.

  The timing chain 21 and the three timing gears 22 to 24 constitute a power transmission system from the crankshaft 9 to the camshafts 12 and 13.

  In this embodiment, a hydraulic variable valve timing mechanism (VVT) 30 is attached only to the intake camshaft 12.

  This variable valve timing mechanism 30 controls the valve timing (opening and closing) of the intake valve 10 by continuously varying the phase of the intake camshaft 12 as necessary, and is composed of, for example, a vane actuator.

  As shown in FIG. 5, a hydraulic variable valve timing mechanism 30 composed of the vane actuator includes a housing 31 fixed so as to be rotatable integrally with a timing gear 22 on one end side in the axial direction of the intake camshaft 12. A vane rotor 32 housed in the housing 31 so as to be relatively swingable in the circumferential direction and fixed integrally with the intake camshaft 12, and a front lid attached to the front surface of the housing 31 with a fastener 34 such as a bolt. 33.

  A plurality of circumferentially recessed portions 31a... Recessed in the radially outward direction are provided at a plurality of circumferential locations (four locations in the figure) on the inner circumference of the housing 31, and a plurality of circumferential locations on the outer circumference of the vane rotor 32. In (the same number as the recesses 31a), vanes 32a... Projecting radially outward are provided.

  Each vane 32a of the vane rotor 32 is inserted in each recess 31a of the housing 31 so as to be capable of swinging in the circumferential direction. If necessary, an advance hydraulic chamber and a pressure chamber are provided on both sides in the circumferential direction of the vane 32a in the recess 21a. A retarded hydraulic chamber (not shown) is secured.

  By controlling the hydraulic pressure supply to either one of these hydraulic chambers by an oil control valve (OCV) 35, the intake side camshaft 12 is driven to the advance side or the retard side.

  The operation of the oil control valve 35 is controlled by the control device 40 in accordance with the operation status of the internal combustion engine 1. The control device 40 is generally composed of a known ECU (Electronic Control Unit).

  The timing chain 21, the timing gears 22 to 24, the variable valve timing mechanism 30 and the like described above are generally arranged outside the front wall of the cylinder block 3, but these are attached to the front wall of the cylinder block 3. The timing chain cover 26 is concealed and protected.

  Next, an oil supply structure in the above-described internal combustion engine 1 will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1 and FIG. 2, in the internal combustion engine 1, oil in an oil pan (oil storage part) 14 provided at the bottom of the cylinder block 3 is pumped up by a single oil pump (OP) 51. After being passed through (OF) 52, it is mainly supplied separately on the cylinder block 3 side and the cylinder head 2 side.

  In addition, since the oil which lubricated each part of the cylinder block 3 and the cylinder head 2 is returned to the oil pan 14, oil circulation in a single closed loop is performed in the internal combustion engine 1.

  The oil pump 51 is rotationally driven by the crankshaft 9 via an appropriate belt (not shown).

  Specifically, the oil supply structure includes a common oil passage 53 for introducing oil pumped up by the oil pump 51 and passed through the oil filter 52 to the cylinder block 3 side, and a first branching from the common oil passage 53 into three systems. The second and third oil passages 54, 55, and 56 are included.

  Although not shown in detail, the common oil passage 53 is provided along the vertical direction inside the cylinder block 3.

  The first oil passage 54 is called a main gallery provided in the cylinder block 3 along the lateral direction (cylinder arrangement direction). Although not shown, the first oil passage 54 has a plurality of crankshafts. Oil is supplied to journals and oil jets for each cylinder.

  The second oil passage 55 is for introducing oil into the valve mechanism 45 (shown only in FIG. 1) in the cylinder head 2. An oil passage 57 that supplies oil to the chain tensioner 25 is connected to the middle of the second oil passage 55.

  The valve operating mechanism 45 includes a rocker arm and a lash adjuster (not shown) related to the intake valve 10 and the exhaust valve 11, journals of the intake side camshaft 12 and the exhaust side camshaft 13, and the like.

  The third oil passage 56 is for introducing oil to the variable valve timing mechanism 30 through the oil control valve 35 in the cylinder head 2.

  The downstream of the oil control valve 35 is connected to an advance hydraulic chamber and a retard hydraulic chamber (reference numerals omitted) of the variable valve timing mechanism 30 through an oil passage (not shown), and each hydraulic chamber is provided as necessary. Appropriate hydraulic pressure is supplied.

  In the example shown in FIG. 1, the upstream end of the second oil passage 55 and the upstream end of the third oil passage 56 are joined, and the upstream end of the joining portion 58 is the first oil passage 54 and the common oil. It is connected in the vicinity of a connection portion 59 with the path 53.

  In this embodiment, the merging portion 58 is disposed in the vicinity of the connecting portion 59 on the downstream side. However, the merging portion 58 may be arranged in the vicinity of the connecting portion 59 and upstream of it.

  In such an oil supply structure, in short, downstream of the oil pump 51, first, the system is branched into two systems of the cylinder block 3 side and the cylinder head 2 side, and then a path toward the cylinder head 2 side immediately after this branching is further provided. The system is branched into two systems, that is, the valve operating mechanism 45 side and the variable valve timing mechanism 30 side.

  By the way, the portion immediately after branching from the common oil passage 53 in the second and third oil passages 55 and 56 is provided not on the inside of the cylinder block 3 but on the inner surface of the timing chain cover 26. Shown and explained.

  That is, the inner surface of the timing chain cover 26 is provided with a groove 26b by a rib-like wall portion 26a protruding in the thickness direction, and a lid-like plate 27 is attached to the opening side of the groove 26b. . By closing the opening of the groove 26 b with the plate 27, a hole-shaped space surrounded by the groove 26 b and the plate 27 is formed as a second oil path 55 and a third oil path 56.

  As shown in FIGS. 4 and 6, the lower end portion of the lower end side joining portion of the groove 26 b is a through hole 27 a provided in the lower end of the plate 27 and a through hole provided in the front wall of the cylinder block 3. It is connected to a common oil passage 53 inside the cylinder block 3 through 3a. Further, the upper-end bifurcated portion of the groove 26 b is connected to the second oil passage 55 and the third oil via the through-holes 27 b and 27 c provided in the upper end of the plate 27 and the through-holes 2 d and 2 e provided in the cylinder head 2. The passage 56 is connected in communication with a portion (see FIG. 2) disposed inside the cylinder head 2.

  In the internal combustion engine 1 having such an oil supply structure, the intake side camshaft 12 and the exhaust side camshaft 13 are driven to rotate through the timing chain 21 as the crankshaft 9 rotates, and the oil pump 51 is driven. Then, the oil in the oil pan 14 is pumped up by the oil pump 51, filtered by the oil filter 52, and then introduced into the common oil passage 53.

  The oil introduced into the common oil passage 53 is lubricated in the cylinder by the crankshaft journal portion and the oil jet through the first oil passage 54, and in each part constituting the valve mechanism 45 through the second oil passage 55. Lubrication is performed, and hydraulic pressure is supplied to the variable valve timing mechanism 30 through the third oil passage 56 and the oil control valve 35.

  As described above, in the oil supply structure of this embodiment, a single oil pump is used and only the oil passage branched into three systems is provided. Therefore, the configuration is simple, and the equipment cost of the internal combustion engine 1 is reduced. This is advantageous for suppression.

  Moreover, the oil branch 51 branches from a common oil passage 53 on the discharge side of the oil pump 51 into a second oil passage 55 toward the valve operating mechanism 45 and a third oil passage 56 toward the variable valve timing mechanism 30 in the region of the cylinder block 3. On the other hand, the upstream side merge portion 58 of the second oil passage 55 and the third oil passage 56 is connected in the vicinity of the connection portion 59 between the first oil passage 54 and the common oil passage 53 toward the inside of the cylinder block 3. ing.

  That is, oil is separately supplied to the valve mechanism 45 side and the variable valve timing mechanism 30 side by separate second and third oil passages 55 and 56. As a result, even if the discharge pressure fluctuation of the oil pump 51 or the hydraulic pressure fluctuation in the second oil passage 55 toward the valve operating mechanism 45 occurs in the low rotation range of the internal combustion engine 1, the hydraulic pressure fluctuation is variable valve timing mechanism. Influencing the oil pressure of the third oil passage 56 toward the 30 side is suppressed or prevented. For this reason, the hydraulic pressure supplied to the variable valve timing mechanism 30 is stabilized even in a low rotational speed region of the internal combustion engine 1, so that the variable valve timing mechanism 30 can be stably operated.

  Further, the third oil passage 56 directed toward the variable valve timing mechanism 30 is connected to the vicinity of the connection portion 59 of the first oil passage 54 directed toward the inside of the cylinder block with respect to the common oil passage 53, whereby variable valve timing is achieved. It is possible to secure the third oil passage 56 toward the mechanism 30 as long as possible. As a result, the volume of the third oil passage 56 can be increased as much as possible, so that a sufficient hydraulic pressure supplied to the variable valve timing mechanism 30 side can be secured, and the hydraulic pressure can be increased. Application can be performed quickly, and the responsiveness is improved.

  In particular, the variable valve timing mechanism 30 may control the advance angle of the intake camshaft 12 during idling rotation of the internal combustion engine 1, and the intake retard camshaft 12 may be the most retarded when the internal combustion engine 1 is stopped. As described above, it is possible to supply sufficient hydraulic pressure to the variable valve timing mechanism 30 with good response, so that the control as described above can be performed accurately and quickly, which is preferable. .

  Hereinafter, other embodiments of the present invention will be described.

  (1) In the above embodiment, the variable valve timing mechanism 30 is provided only on the intake side. However, the variable valve timing mechanism 30 may be provided only on the exhaust side or on both the intake side and the exhaust side. The present invention can be applied.

  (2) In the above embodiment, a direct injection gasoline engine is exemplified as the internal combustion engine 1, but the present invention can also be applied to a lean combustion engine such as a diesel engine or a gas engine.

  (3) In the above embodiment, an example is given in which a part of the second and third oil passages 55 and 56 is provided on the inner surface of the timing chain cover 26, but it may be formed inside the cylinder block 3, Such a thing is also included in this invention.

1 is a conceptual diagram schematically showing an embodiment of an oil supply structure for an internal combustion engine according to the present invention. It is a perspective view which shows three-dimensionally piping of the oil supply structure shown in FIG. It is a schematic block diagram which shows the internal combustion engine to which the oil supply structure shown in FIG. 1 is applied. FIG. 4 is a side view schematically showing a power transmission system from a crankshaft to a camshaft of the internal combustion engine of FIG. 3. It is a perspective view which shows the variable valve timing mechanism of FIG. It is a front view which shows the inner surface of the timing chain case attached to the internal combustion engine of FIG. It is an arrow view of the (7)-(7) line cross section of FIG.

Explanation of symbols

1 Internal combustion engine
2 Cylinder head
3 Cylinder block 14 Oil pan 21 Timing chain 26 Timing chain cover 26a Rib-like wall portion 26b Groove forming part of second and third oil passages 27 Plate forming part of second and third oil passages 30 Variable Valve timing mechanism 35 Oil control valve 40 Control device 45 Valve mechanism 51 Oil pump 52 Oil filter 53 Common oil passage 54 First oil passage 55 Second oil passage 56 Third oil passage

Claims (3)

An oil supply structure for an internal combustion engine in which a hydraulic variable valve timing mechanism is provided on at least one of an intake side camshaft and an exhaust side camshaft,
A common oil passage that sucks oil in the oil reservoir with a single oil pump and leads it to the cylinder block side; from the common oil passage to the inside of the cylinder block, the valve mechanism side in the cylinder head, and the variable valve timing mechanism side; And three oil passages individually leading to
The upstream end of the oil passage toward the valve operating mechanism side and the upstream end of the oil passage toward the variable valve timing mechanism side are connected in the vicinity of the connection portion between the oil passage toward the inside of the cylinder block and the common oil passage. An oil supply structure for an internal combustion engine.   The upstream end of the oil passage toward the valve mechanism and the upstream end of the oil passage toward the variable valve timing mechanism are joined together, and the upstream end of the joining portion is connected to the predetermined portion. An oil supply structure for an internal combustion engine, wherein 3. The timing chain cover according to claim 1, wherein each of the oil passage toward the valve mechanism and the oil passage toward the variable valve timing mechanism is detachably attached to the outside of the wall of the cylinder block. An oil supply structure for an internal combustion engine, comprising a hole-shaped space surrounded by a groove formed integrally with the plate and a plate attached to the groove so as to close the opening side.

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