JP5682498B2 - Direct injection internal combustion engine - Google Patents

Description

  The present invention relates to a direct injection internal combustion engine, and more particularly to an injector mounting structure in a direct injection internal combustion engine.

  Generally, an injector (also referred to as a fuel injection valve, a fuel injection nozzle, etc.) mounting structure in a direct injection internal combustion engine represented by a diesel engine is as follows. That is, the lower end portion of the injector is inserted into a mounting hole provided on the upper surface of the cylinder head, a forked or fork-like clamp member is engaged with the upper end portion of the injector, and the clamp member is fixed to the cylinder head with a bolt. At this time, the injector is fixed so as to be pressed into the mounting hole by the downward force generated in the clamp member.

  Moreover, in patent document 1, the cam bracket which rotatably supports two camshafts in common is fixed to a cylinder head by the stud bolt in the position between camshafts. A male screw is formed at the upper end portion of the stud bolt, and a hole of a clamp member is inserted therein, and a nut is fastened.

Japanese Patent Laid-Open No. 10-176629

  By the way, a general injector mounting structure is a structure in which the mounting of the injector is completed in the head cover, that is, in a cam chamber where a camshaft, an intake / exhaust valve and the like are present. Therefore, for example, when the injector is attached / detached for inspection, repair, replacement, etc., the head cover must be removed, which is difficult in terms of disassembly / assembly and workability.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a direct injection internal combustion engine that can improve the disassembly and assembly and workability when an injector is attached and detached.

According to one aspect of the invention,
A cam housing and a head cover are sequentially attached on the cylinder head, and an injector is inserted into a cover hole provided in the head cover and a head hole provided in the cylinder head, and the injector is inserted onto the head cover using a clamp member. A fixed direct injection internal combustion engine,
A bolt insertion hole is provided in the clamp member, a female screw hole is provided in a top portion of a head bolt to which the head cover is attached, a clamp mounting bolt is fastened to the female screw hole through the bolt insertion hole, and the clamp member There is provided a direct injection internal combustion engine characterized in that the injector is pushed down and fixed.

  Preferably, the head bolt comprises a through bolt that fastens the cam housing and the head cover together with the cylinder head.

  Preferably, the cam housing includes a cam carrier that rotatably supports a lower half surface of the camshaft, and a bearing cap that rotatably supports the upper half surface of the camshaft is attached to an upper portion of the cam carrier. In addition, a head bolt insertion hole for allowing the head bolt to pass through the bearing cap is provided, and the bearing cap is brought into contact with the head cover around an upper end opening of the head bolt insertion hole of the bearing cap.

  Preferably, in the head cover, a predetermined portion including a pressure receiving surface on which pressure from the head bolt acts is formed thicker than a portion adjacent to the predetermined portion.

  Preferably, the injector is disposed to be inclined with respect to a cylinder center axis, the clamp member has a clamp engagement surface for applying a downward force to the injector, and the clamp engagement surface is inclined with respect to the injector. In order to compensate for the deviation, the clamp member is inclined with respect to a direction perpendicular to the cylinder central axis in the mounted state.

  According to the present invention, it is possible to improve the disassembly / assembly and workability when the injector is attached and detached.

1 is a perspective view of a direct injection internal combustion engine according to an embodiment of the present invention. It is a perspective view of a cylinder head. It is sectional drawing of the principal part in an assembly state. It is a schematic partial perspective view of a cam housing. It is a bottom view of a head cover. It is sectional drawing when showing other embodiment and cutting in the engine width direction. It is a figure which shows a clamp member.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a direct injection internal combustion engine of the present embodiment. In the internal combustion engine (engine) 1 of the present embodiment, a compression ignition type internal combustion engine, that is, a diesel engine is configured using basic components of a spark ignition type internal combustion engine, that is, a gasoline engine. This is so-called gasoline engine diesel. And the injector 2 which injects a fuel directly in a cylinder using the spark plug insertion hole in a gasoline engine is attached. A head cover 5 is mounted on the cylinder head 3 with a cam housing 4 interposed. That is, the cam housing 4 and the head cover 5 are sequentially attached on the cylinder head 3 in this order.

  FIG. 2 shows the cylinder head 3 alone. FIG. 3 shows a cross-sectional view of the main part in the assembled state. FIG. 4 partially shows the cam housing 4. The engine 1 of this embodiment is a multi-cylinder diesel engine, for example, an in-line four-cylinder diesel engine.

  Here, the coordinate system is defined as follows. 1 and 2, the left-right direction is the crankshaft direction or the engine longitudinal direction, and the left side is front and the right side is rear for convenience. In FIG. 3, the front and rear are reversed with respect to FIGS. A direction perpendicular to the crankshaft direction or the engine longitudinal direction on the horizontal plane is referred to as a crankshaft vertical direction or an engine width direction. This direction coincides with the thickness direction in FIG. The direction perpendicular to both the engine longitudinal direction and the engine width direction is the vertical direction or the engine up-down direction. As shown in FIG. 3, the center axis 6C of the cylinder 6 and the center axis 2C of the injector 2 are coaxial with each other and parallel to the engine vertical direction.

  The cylinder head 3 is generally formed in a bathtub shape. Although not shown, the cylinder head 3 has a plurality of intake ports, exhaust ports, valve holes, water jackets, and the like. The lower surface or contact surface 8 of the cam housing 4 is brought into contact with the upper surface or contact surface 7 located at the outer peripheral edge of the cylinder head 3.

  As is well known, the cam housing 4 is generally ladder-shaped as a whole, and integrally includes a plurality of cam carriers 4A that rotatably support an intake camshaft (not shown) and a lower half surface of the exhaust camshaft 60. The cam carrier 4A is disposed at a position corresponding to the front and rear ends of the intake camshaft and the exhaust camshaft 60 and the position between the cylinders in the longitudinal direction of the engine. A bearing cap 61 that rotatably supports the upper half surfaces of the intake camshaft and the exhaust camshaft 60 is attached to the cam carriers 4A by bolts 62, respectively. Bolt holes for the bolt 62 are indicated by 63 and 64. The cam carrier 4A and the bearing cap 61 extend in the engine width direction over almost the entire width of the cam housing 4.

  The lower surface or contact surface 10 of the head cover 5 is brought into contact with the upper surface or contact surface 9 located at the outer peripheral edge of the cam housing 4. A cover gasket (not shown) is interposed between the contact surfaces 9 and 10. When the cylinder head 3, the cam housing 4 and the head cover 5 are brought into contact with each other and assembled, a valve operating chamber or a cam chamber 11 sealed by these three members is defined. The cam chamber 11 accommodates an unillustrated intake valve, exhaust valve, valve spring, rocker arm, and the like. In this embodiment, a four-valve type having two intake valves and two exhaust valves per cylinder is employed.

  A head hole 12 for inserting the lower end portion of the injector 2 is provided in the inner bottom surface portion of the cylinder head 3. The head cover 5 is also provided with a cover hole 13 for inserting the vicinity of the upper end of the injector 2. Each of these holes 12 and 13 is provided for each cylinder, and corresponds to a spark plug insertion hole in the base gasoline engine.

  As shown in FIG. 3, the head hole 12 has a stepped shape that is reduced in diameter toward the lower side so as to follow the shape of the lower end portion of the injector 2. The bottom of the head hole 12 is penetrated so as to open into the combustion chamber 14. Through this small-diameter through hole 15, the axial tip 2 </ b> A of the injector 2 extends downward, and an injection hole 2 </ b> B serving as a fuel outlet of the injector 2 faces the combustion chamber 14. The ceiling surface 14A of the combustion chamber 14 is shaped like a pent roof, similar to a gasoline engine. A piston 17 having an annular cavity 16 is disposed in the cylinder 6 so as to be slidable up and down.

  First, an injector tube 19 is inserted into the head hole 12 by press fitting or the like, and then a ring-shaped metal gasket 18 is inserted into the bottom of the head hole 12. Then, the injector 2 is inserted into the injector tube 19 from above, and the axial tip portion 2A of the injector 2 passes through the through hole 15 and the gasket 18 of the cylinder head 3. When the injector 2 is pushed down by a clamp member 21, which will be described later, the injector 2, the gasket 18, and the cylinder head 3 are in close contact with each other so as not to leak fluid.

  The injector tube 19 corresponds to a plug tube in a gasoline engine and is exposed in the cam chamber 11. The injector tube 19 isolates the cam chamber 11 and the injector 2, and prevents the oil in the cam chamber 11 from scattering and adhering to the injector 2.

  A cylindrical packing 61A made of an elastic material such as rubber is attached to the cover hole 13, and the injector tube 19 is inserted into the packing 61A. The injector tube 19 protrudes above the head cover 5 and the packing 61A in the attached state. The packing 61A prevents the oil in the cam chamber 11 from leaking out.

  As shown in FIG. 1, a cam housing 4 and a head cover 5 are attached to the cylinder head 3. An injector tube 19 is attached in advance to the head hole 12 of the cylinder head 3, and a packing 61 </ b> A (not shown in FIG. 1) is attached in advance to the cover hole 13 of the head cover 5. Simultaneously with the attachment of the head cover 5, the injector tube 19 is inserted into the packing 61A from below. Thereafter, the injector 2 is inserted into the injector tube 19 from above with the gasket 18 fitted and held on the axial tip 2A of the injector 2 or with the gasket 18 disposed in advance in the inner bottom of the head hole 12. .

  In such an inserted arrangement state of the injector 2, as shown in FIG. 3, the upper end portion of the injector 2 protrudes above the head cover 5 and is exposed to the outside. Therefore, the injector 2 is fixed using the protruding portion or the exposed portion. A clamp member 21 is used for this fixing. That is, the injector 2 is fixed on the head cover 5 using the clamp member 21.

  The clamp member 21 has a generally fork-like shape, and a bifurcated clamp engagement portion 23 that contacts or engages with an injector engagement portion 22 formed at the upper end portion of the injector 2 is formed at the tip thereof. . The clamp engaging portion 23 engages with the injector engaging portion 22 in such a manner as to sandwich the injector engaging portion 22 from the side. A clamp engagement surface 23A is formed on the lower surface of the clamp engagement portion 23, and the injector engagement portion 22 is an upward injector that contacts the clamp engagement surface 23A and receives a downward force from the clamp engagement portion 23. An engagement surface 24 is formed. The injector engagement surface 24 is perpendicular to the injector central axis 2C.

  A bolt insertion hole 25 is provided at the center of the clamp member 21. Further, a spherical portion 26 is formed to protrude from the lower surface of the base end portion of the clamp member 21. As will be understood later, the clamp member 21 presses the injector 2 downward on the basis of the lever principle with the spherical portion 26 as a fulcrum, the bolt insertion hole 25 as a force point, and the clamp engaging portion 23 as an action point.

  A pivot base 27 that receives the spherical portion 26 of the clamp member 21 is attached to the upper surface 5 </ b> A of the head cover 5. The pivot base 27 has a spherical portion 28 at its upper end surface, and this spherical portion 28 receives the spherical portion 26 of the clamp member 21 and rotatably supports it. The pivot base 27 has a male screw 65 at its lower end, and this male screw 65 is screwed and fastened into a screw hole 29 provided in the upper surface 5 </ b> A of the head cover 5. In addition, the attachment method of the pivot base 27 is arbitrary, In addition, an interference fit, a clearance fit, etc. are possible.

  A head bolt 29 is used to attach the head cover 5. In particular, the head bolt 29 in the present embodiment is a relatively long through bolt (through bolt), and the cam housing 4 and the head cover 5 are fastened to the cylinder head 3 together.

  A head bolt hole 30 is formed through the head cover 5. A post 31 protruding upward is integrally formed on the inner bottom surface of the cylinder head 3. A female screw 32 is provided on the inner peripheral portion of the post 31. A male screw 33 is provided at the lower end of the head bolt 29, and a hexagonal tool engaging portion 34 and an enlarged-diameter seat portion 35 are integrally provided at the top of the head bolt 29. A metal (for example, copper) washer 36 for sealing is interposed between the enlarged-diameter seat 35 and the head cover upper surface 5A.

  The cam carrier 4A and the bearing cap 61 of the cam housing 4 are provided with head bolt insertion holes 66 and 67 through which the head bolt 29 is inserted. These head bolt insertion holes 66 and 67 are located at a substantially intermediate position between the intake camshaft and the exhaust camshaft 60 in the engine width direction. In particular, as shown in FIG. 3, the bearing cap 61 is brought into contact with the back surface portion of the head cover 5 around the upper end opening of the head bolt insertion hole 67 of the bearing cap 61. Further, the cam carrier 4A is brought into contact with the post 31 of the cylinder head 3 around the lower end opening of the head bolt insertion hole 66 of the cam carrier 4A.

  After the cam housing 4 and the head cover 5 are placed on the cylinder head 3, the head bolt 29 to which the washer 36 is attached is sequentially inserted through the head bolt hole 30 and the head bolt insertion holes 66 and 67. Screwed into the female screw 32. The cam housing 4 and the head cover 5 are fastened together with the cylinder head 3 by engaging a tool such as a box wrench with the tool engaging portion 34 of the head bolt 29 and tightening the head bolt 29.

  At this time, since the head cover 5 is in contact with the bearing cap 61, a downward load on the head cover 5 is received by the bearing cap 61 and the cam carrier 4A, and by extension, the cylinder head 3, and deformation and dent of the head cover 5 are prevented.

  A female screw hole 37 is provided at the top of the head bolt 29 or the tool engaging portion 34, particularly at the top surface portion thereof. The clamp member 21 is attached by the clamp attachment bolt 38 using the female screw hole 37.

  A male screw 39 is provided at the lower end of the clamp mounting bolt 38, and a hexagonal tool engaging portion 40 and an enlarged-diameter seat portion 41 are integrally provided at the top of the clamp mounting bolt 38. Between the enlarged-diameter seat portion 41 and the clamp member 21, a spherical washer 42 having a spherical lower surface is interposed. A spherical seat 73 that is rounded into a spherical shape is formed on the peripheral edge of the upper end of the bolt insertion hole 25 of the clamp member 21 so as to receive the spherical surface of the spherical washer 42 in surface contact.

  With the clamp member 21 placed on the pivot base 27 and the injector engaging portion 22, the clamp mounting bolt 38 to which the ball washer 42 is mounted is inserted through the bolt insertion hole 25 of the clamp member 21, and then the female of the head bolt 29. It is screwed into the screw hole 37. By engaging a tool such as a box wrench with the tool engaging portion 40 of the clamp mounting bolt 38 and tightening the clamp mounting bolt 38, a downward force or force from the clamp mounting bolt 38 around the bolt insertion hole 25 of the clamp member 21. Pressure is applied. Then, the clamp member 21 is rotated or tilted downward with the spherical surface portion 26 as a fulcrum, and the injector 2 is pushed down by the clamp engaging portion 23. As a result, the injector 2 is pressed toward the bottom of the head hole 12 and fixed.

  At this time, slight inclination errors between the members due to manufacturing errors and assembly errors are absorbed by the spherical support structure of the base end portion of the clamp member 21 and the spherical mounting structure of the clamp mounting bolt 38.

  For example, as shown in FIG. 3, the clamp member 21 is scheduled to fix the injector 2 in a horizontal state, but even if the clamp member 21 is slightly inclined from the horizontal state to fix the injector 2, The spherical surface portion 26 of the clamp member 21 rotates with respect to the spherical surface portion 28 of the pivot base 27 to absorb the tilt error.

  Further, for example, as shown in FIG. 3, the clamp mounting bolt 38 is intended to push down the clamp member 21 from a direction perpendicular thereto, but the angle between the clamp mounting bolt 38 and the clamp member 21 is a right angle. Even if the ball washer is slightly moved, the ball washer 42 rotates relative to the spherical seat 73 of the clamp member 21 and absorbs the tilt error. The downward load of the clamp mounting bolt 38 can be efficiently transmitted to the clamp member 21 in the same manner as when pushed down from the perpendicular direction.

  The injector mounting structure described above is similarly provided for each cylinder. As described above, the injector 2 is arranged and fixed so that the central axis 2C thereof is parallel to the cylinder central axis 6C. The head bolt 29 is also attached so that its central axis is parallel to the cylinder central axis 6C, and the central axis of the female screw hole 37 provided in the head bolt 29 is also parallel to the cylinder central axis 6C. Accordingly, the central axis of the clamp mounting bolt 38 attached to the female screw hole 37 is also parallel to the cylinder central axis 6C.

  The injector 2 is arranged upright in the vicinity of the cylinder center axis 6C between the four valves, and is located at an approximately middle position in the engine width direction. The clamp member 21 is disposed along the engine longitudinal direction. The head bolt 29 is disposed at a position between the intake camshaft and the exhaust camshaft 60 in the engine width direction and at the positions of the cam carrier 4A and the bearing cap 61 in the engine longitudinal direction.

  Here, as shown in FIG. 5, in the head cover 5, a predetermined portion including a pressure receiving surface to which pressure from the head bolt 29 acts is formed thicker than a portion adjacent to the predetermined portion.

  Specifically, a long portion 45 including a cover hole 13, a head bolt hole 30, and a screw hole 29 aligned in a straight line along the engine longitudinal direction is provided in the head cover 5. It is formed thicker than adjacent parts. Here, the elongated portion 45 has a rectangular shape extending in the engine longitudinal direction, and is formed by projecting the inner surface or the rear surface of the head cover 5. The pressure receiving surface on which the pressure from the head bolt 29 acts is naturally included in the elongated portion 45. The elongated portion 45 includes a cover hole 13, a head bolt hole 30, and a screw hole 29 for all cylinders.

  By increasing the thickness of the elongated portion 45 in this way, the rigidity of the head cover 5 can be improved, and deformation of the head cover 5 when a downward fastening load is applied from the head bolt 29 can be suppressed. Further, the long portion 45 suppresses the deformation of the head cover 5 even with a downward load from the pivot base 27.

  The portion near the contact surface 10 of the head cover 5 that contacts the contact surface 9 of the cam housing 4 is also thickened, and the rigidity of the head cover 5 is improved. The portions other than these thick portions are generally thin, and the head cover 5 is lightened.

  An outline of the injector mounting method in the present embodiment will be described below. First, the cam housing 4 is placed on the cylinder head 3 in which the valve system parts are incorporated, and the cam housing 4 is fixed to the cylinder head 3 with a plurality of bolts (not shown) at the outer peripheral edge portions of both. At this time, the bolt is inserted into the bolt insertion hole 68 (see FIG. 1) of the cam housing 4, and the bolt is tightened into the female screw hole 69 (see FIG. 2) of the cylinder head 3.

  Next, the intake camshaft and the exhaust camshaft 60 are placed on the cam carrier 4A of the cam housing 4, and the bearing cap 61 is attached to the cam carrier 4A with bolts 62. At this time, before attaching the bolt 62, the bearing cap 61 may be temporarily fixed by the temporary fixing bolt 70 (see FIG. 1) using the head bolt insertion holes 66 and 67 of the cam carrier 4A and the bearing cap 61.

  The intake camshaft and the exhaust camshaft 60 tend to be lifted by a reaction force from the valve spring, and it is necessary to attach the bearing cap 61 while compressing the valve spring. For this reason, it is convenient to temporarily tighten the bearing cap 61 with the temporary fixing bolt 70 before the final tightening of the bearing cap 61 with the bolt 62. Thereby, when the bearing cap 61 is finally tightened, the positions of the intake cam shaft and the exhaust cam shaft 60 and the bolt tightening torque can be accurately managed, and the assembly accuracy can be improved.

  Note that the temporary fixing bolt 70 is tightened into the female screw 32 of the cylinder head 3 during temporary tightening. When the final tightening is completed, the temporary fixing bolt 70 is removed.

Next, the injector tube 19 is inserted into the head hole 12 of the cylinder head 3. Then, the head cover 5 on which the packing 61 </ b> A is attached in advance is placed on the cam housing 4. At this time, the injector tube 19 is inserted into the packing 61A from below.
The head cover 5 is fixed to the cam housing 4 with a plurality of bolts (not shown) at the outer peripheral edges of the cam housing 4 and the head cover 5. At this time, the bolt is inserted into the bolt insertion hole 71 (see FIG. 1) of the head cover 5, and the bolt is tightened into the female screw hole 72 (see FIG. 1) of the cam housing 4.

  When the head cover 5 is attached to the intermediate stage in this way, the back surface of the head cover 5 comes into contact with the bearing cap 61 as shown in FIG.

  Thereafter, the head bolt 29 to which the washer 36 is attached is sequentially inserted through the head bolt hole 30 and the head bolt insertion holes 66 and 67 and is fastened to the female screw 32 of the cylinder head 3. Thereby, the attachment of the head cover 5 is completed.

  Next, the gasket 18 and the injector 2 are inserted into the injector tube 19 from above. Thereby, the injector 2 is arranged at a fixed position.

  Next, the injector 2 is fixed using the portion of the injector 2 protruding on the head cover 5. That is, the pivot base 27 is attached on the head cover 5. This may be attached in advance. Then, the clamp member 21 is placed on the pivot base 27 and the injector engaging portion 22. The clamp attachment bolt 38 to which the ball washer 42 is attached is inserted through the bolt insertion hole 25 of the clamp member 21 and then tightened into the female screw hole 37 of the head bolt 29. Thereby, the injector 2 is pushed down and fixed.

  As described above, according to the injector mounting structure of this embodiment, the injector 2 is fixed using the clamp member 21 on the head cover 5, that is, outside the head cover 5. That is, the clamp member 21 and the clamp mounting bolt 38 that fastens the clamp member 21 to the head bolt 29 are on the head cover 5, that is, outside the head cover 5. The injector 2 is completely attached outside the cam chamber 11 but not in the cam chamber 11. Therefore, for example, when the injector 2 is attached / detached for inspection, repair, replacement, etc., it is not necessary to remove the head cover 5, and it is possible to improve disassembly / assembly and workability. Since the injector can be attached and detached in a relatively wide space on the head cover 5, it is very advantageous for improving disassembly and assembly and workability.

  Of course, even when a new engine is assembled, the injector 2 can be assembled from the outside after the head cover 5 is fixed to some extent, so that the assembling work is easy. Further, it is possible to prevent an increase in assembly error due to difficulty in assembly, and consequently a quality defect associated therewith.

  Further, since the female screw hole 37 is provided at the top of the head bolt 29 and the clamp mounting bolt 38 is fastened to the female screw hole 37 and the clamp member 21 is attached, the mounting operation on the head cover 5 as described above is further facilitated. It is possible to As in Patent Document 1, it is assumed that a male screw is provided at the top of the head bolt 29 instead of the female screw hole 37 and the clamp member 21 is attached with a nut. Then, while holding the state where the clamp member 21 is engaged with the injector 2, the male screw of the head bolt 29 is inserted into the bolt insertion hole of the clamp member 21 at the same time as the injector 2 is inserted into the cover hole 13 and the head hole 12. 25 must be inserted. This is because the clamp member 21 can normally be inserted into the injector 2 only from the side. In other words, two places must be inserted simultaneously while maintaining the relative positions of the two parts. This work is complicated.

  On the other hand, in the case of this embodiment, two parts can be assembled | attached separately and two places can be inserted separately. That is, first, the injector 2 is inserted into the injector tube 19, and then the clamp member 21 is engaged with the injector 2. Next, the clamp mounting bolt 38 is inserted into the bolt insertion hole 25 of the clamp member 21 and tightened into the female screw hole 37 of the head bolt 29. Thus, the work can be made much easier than in the virtual example.

  In addition, in the present embodiment, since the head bolt 29 composed of a through bolt for fastening the head cover 5 and the cam housing 4 together is used, the cam housing 4 is bolted to the cylinder head 3 alone at the position of the head bolt 29. Compared with, the number of parts can be reduced and the reliability can be improved.

  However, the head bolt 29 provided with the female screw hole 37 is not necessarily a through bolt. Any head bolt exposed to the outside on the head cover 5 can be used.

  Next, another embodiment will be described. In addition, description is abbreviate | omitted about the part same as the said embodiment (it is called basic embodiment), and it demonstrates focusing on difference below.

  FIG. 6 shows the arrangement of the injectors 2 in another embodiment. As shown in the figure, when the gasoline engine is made diesel, the ceiling surface 14A of the combustion chamber 14 has a pent roof shape, and the intake side (right side in the figure) and exhaust side ( The ceiling surface 14A is inclined downward (to the left in the figure). Since the intake valve has a larger diameter than the exhaust valve, the opening position of the through hole 15 is offset to the exhaust side with respect to the cylinder central shaft 6C, and the injector central shaft 2C is inclined with respect to the cylinder central shaft 6C as shown in the figure. Sometimes. That is, the injector 2 may be arranged to be inclined with respect to the cylinder center direction. An inclination angle of the injector central axis 2C with respect to the cylinder central axis 6C is α. In this example, the injector central axis 2C is inclined toward the exhaust side with respect to the cylinder central axis 6C.

  On the other hand, the central axis of the head bolt 29 in the mounted state, its female screw hole 37, and the clamp mounting bolt 38 is parallel to the cylinder central axis 6C, as in the basic embodiment.

  In such an inclined injector arrangement, when the clamp mounting bolt 38 is tightened into the female screw hole 37 in order to press and fix the injector 2 by the clamp member 21, the clamp mounting bolt 38 pushes down the clamp member 21 (to the cylinder center axis 6C). And the direction in which the injector 2 should be pushed down (the direction inclined by α with respect to the cylinder center axis 6C) does not match, and there is a possibility that the pressing load on the injector 2 will be insufficient, resulting in poor mounting. is there. Further, there is a possibility that the clamp member 21 hits the injector 2.

  Therefore, in the present embodiment, as shown in FIG. 7, the clamp engagement surface formed on the lower surface of the clamp engagement portion 23 of the clamp member 21 so as to compensate or absorb the tilt deviation of the injector 2 with respect to the cylinder center axis 6 </ b> C. 23A is inclined. That is, the clamp engaging surface 23A of the clamp member 21 in the attached state is formed so as to be inclined by the inclination angle α with respect to the direction perpendicular to the cylinder center axis 6C. Here, in the mounting state of the head bolt 29 and the clamp member 21, the female screw hole 37 and the bolt insertion hole 25 are coaxial, and their central axes are parallel to the cylinder central axis 6C. In other words, it is inclined with respect to a direction perpendicular to the central axis of the bolt insertion hole 25.

  7A is a plan view of the clamp member 21, FIG. 7B is a front view thereof, FIG. 7C is a cross-sectional view taken along the line cc in FIG. 7A, and FIG. 7D is a perspective view of the clamp member 21. ) Is a side view of (B). Z is a central axis of the bolt insertion hole 25, which is parallel to the cylinder central axis 6 </ b> C in the attached state of the clamp member 21. Y is a direction perpendicular to the central axis Z (hereinafter referred to as a right angle direction).

  As illustrated, the clamp engagement surface 23A is inclined with respect to the perpendicular direction Y by an inclination angle α. And this inclination direction is inclined so that it goes down as it goes to the exhaust side, following the inclination arrangement of the injector 2. Correspondingly, the inner side surface 23B of the clamp engaging portion 23 is also inclined by the inclination angle α with respect to the direction of the central axis Z of the bolt insertion hole 25. The clamp engagement surface 23A and the inner side surface 23B are perpendicular to each other. The upper surface 23C of the clamp engaging portion 23 is parallel to the perpendicular direction Y.

  In the case of the present embodiment, a circular arc surface 50 is formed to protrude from the clamp engagement surface 23A. The arcuate surface 50 can reliably transmit the downward pressing force to the injector engaging surface 24 even if the clamp member 21 is attached with a slight inclination from the position planned around the fulcrum (spherical portion 26). To. Such a circular arc surface 50 can be provided in the basic embodiment, or can be omitted. The arc surface 50 is in line contact with the injector engagement surface 24.

  When the inclined injector 2 is fixed by using the clamp member 21, the pressing force F1 in the cylinder central axis direction generated when the clamp mounting bolt 38 is tightened is changed to a pressing force F2 inclined by α with respect to this. In other words, the pushing force F2 is applied to the injector engaging surface 24 at a right angle, and the injector 2 can be pushed down along the direction of the central axis 2C. Therefore, it is possible to apply a sufficient pressing load to the injector 2 and prevent the mounting failure of the injector 2 beforehand. In addition, it is possible to prevent the clamp member 21 from hitting one piece.

  It is also possible to form the entire upper surface of the clamp member 21 so as to be inclined so as to be parallel to the clamp engagement surface 23A. In this case, although the direction of the pressing force from the clamp mounting bolt 38 is not perpendicular to the upper surface of the clamp member 21, the pressing force can still be applied to the clamp member 21 almost uniformly by using the ball washer 42. In addition, it is possible to prevent the bias of the pressing load.

  The preferred embodiment of the present invention has been described in detail above, but various other embodiments of the present invention are conceivable. The present invention is also applicable to a general diesel engine that is not based on a gasoline engine. The present invention can be applied not only to a DOHC engine having an intake camshaft and an exhaust camshaft but also to an SOHC engine having only one camshaft.

  The embodiment of the present invention is not limited to the above-described embodiment, and includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Injector 3 Cylinder head 4 Cam housing 4A Cam carrier 5 Head cover 6 Cylinder 6C Cylinder center axis | shaft 12 Head hole 13 Cover hole 21 Clamp member 23A Clamp engagement surface 25 Bolt insertion hole 29 Head bolt 37 Female screw hole 38 Clamp attachment bolt 45 Long part 60 Exhaust cam shaft 61 Bearing cap 66, 67 Head bolt insertion hole

Claims (3)

A cam housing and a head cover are sequentially attached on the cylinder head, and an injector is inserted into a cover hole provided in the head cover and a head hole provided in the cylinder head, and the injector is inserted onto the head cover using a clamp member. A fixed direct injection internal combustion engine,
A bolt insertion hole is provided in the clamp member, a female screw hole is provided in a top portion of a head bolt to which the head cover is attached, a clamp mounting bolt is fastened to the female screw hole through the bolt insertion hole, and the clamp member Push down on the injector to fix it,
The head bolt comprises a through bolt that fastens the cam housing and the head cover together with the cylinder head;
The cam housing has a cam carrier that rotatably supports a lower half surface of a camshaft, and a bearing cap that rotatably supports the upper half surface of the camshaft is attached to an upper portion of the cam carrier, and the cam carrier and A head bolt insertion hole for allowing the head bolt to pass through the bearing cap is provided, and the bearing cap is in contact with the head cover around the upper end opening of the head bolt insertion hole of the bearing cap, and the cam carrier A direct injection internal combustion engine , wherein the cam carrier is brought into contact with the cylinder head around a lower end opening of a head bolt insertion hole . Among the head cover, straight of claim 1, the pressure from the head bolt predetermined site comprising pressure surface which acts, characterized in that it is formed thicker than the portion adjacent to the predetermined site Injection internal combustion engine. The injector is disposed to be inclined with respect to a cylinder center axis, the clamp member has a clamp engagement surface for applying a downward force to the injector, and the clamp engagement surface compensates for a tilt deviation of the injector. to such, direct injection internal combustion engine according to claim 1 or 2, characterized in that it is inclined with respect to the direction perpendicular to the cylinder center axis in the mounted state of the clamping member.

Images