Patent Grant
10119436
The present application claims priority to Japanese Patent Application No. 2016-116854 filed on Jun. 13, 2016, which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to an internal combustion engine that has a dual lubricating oil circulation passage.
2. Description of the Related Art
There is known an internal combustion engine having a dual lubricating oil circulation passage.
Such an internal combustion engine includes a cylinder block, a cylinder head, a cylinder head cover, an oil pan and a chain cover.
A cylinder bore is formed inside the cylinder block. A pistons is slidably provided in the cylinder bore.
The oil pan is connected to the bottom portion of the cylinder block. The lower space of the cylinder block and a crank shaft storage space, which is the interior space of the oil pan, are communicated with the cylinder bore. In addition, the crank shaft storage space stores a crank shaft that rotates in conjunction with the operation of the piston.
The cylinder head is connected to the upper portion of the cylinder block. The space defined by a recess formed in the bottom portion of the cylinder head, the cylinder bore, and the upper end surface of the piston constitutes a combustion chamber. An intake valve and an exhaust valve, both of which can move upward and downward, are provided inside the cylinder head. Additionally, an inlet port and an exhaust port, which communicate with the recess (the combustion chamber) and are opened and closed by the intake valve and the exhaust valve respectively, are formed in the cylinder head.
A camshaft storage space is formed inside the cylinder head. The camshaft storage space, whose top surface is opened, is independent from the recess (the combustion chamber), the inlet port and the exhaust port. In other words, the camshaft storage space does not communicate with the recess, the inlet port and the exhaust port.
A camshaft, which extends linearly and is rotatable about its own axis, is disposed in the camshaft storage space. A through-hole is formed through a chain cover adjacent wall that constitutes a part of the outer peripheral wall of the cylinder head. One end of the camshaft passes through this through-hole and protrudes out of the cylinder head. An oil seal is provided between the inner peripheral surface of the through-hole and the outer peripheral surface of the camshaft. This oil seal is in contact with the inner peripheral surface of the through-hole and the outer peripheral surface of the camshaft in an air-tight and water-tight manner.
As is well known, both the intake valve and the exhaust valve are interlocked with the camshaft. Namely, when the camshaft rotates, the intake valve and the exhaust valve operate to open and close the inlet port and the exhaust port, respectively.
The cylinder head cover is fixed to the top surface of the cylinder head. Namely, the top surface of the cylinder head is covered with the cylinder head cover.
The chain cover is fixed to the cylinder block, the cylinder head, and the oil pan.
A chain storage space is formed inside the chain cover. This chain storage space communicates with the crank shaft storage space of the oil pan. On the other hand, the chain storage space does not communicate with the camshaft storage space. Namely, the chain cover adjacent wall of the cylinder head separates the camshaft storage space from the chain storage space in an in-air-tight and water-tight manner.
The one end of the camshaft, which passes through the through-hole of the chain cover adjacent wall, is located in the chain storage space. A timing chain, which is arranged in both the chain storage space and the interior space of the oil pan, is wounded around a sprocket provided at one end of the camshaft and a sprocket provided at one end of the crank shaft. Namely, the crank shaft and the camshaft are interlocked by the timing chain so that the camshaft is rotated by the rotational force of the crank shaft.
The crank shaft storage space of the oil pan is filled with a first lubricating oil.
In addition, the crank shaft storage space is equipped with a first oil pump to circulate the first lubricating oil through the crank shaft storage space, the interior space of the cylinder block, and the chain storage space. Namely, a first lubricating oil circulation passage is formed so as to pass through the crank shaft storage space, the interior space of the cylinder block, and the chain storage space.
On the other hand, a sub oil pan, which communicates with the camshaft storage space, is formed in the cylinder head. The sub oil pan is filled with a second lubricating oil.
In addition, the camshaft storage space is equipped with a second oil pump to circulate the second lubricating oil through the sub oil pan and the camshaft storage space. Namely, a second lubricating oil circulation passage is formed so as pass through the sub oil pan and the camshaft storage space.
Then, when the first oil pump is operated, the first lubricating oil circulates through the first lubricating oil circulation passage, and when the second oil pump is operated, the second lubricating oil circulates through the second lubricating oil circulation passage.
The first lubricating oil circulating through the first lubricating oil circulation passage enables the piston, the crank shaft, and the timing chain to operate smoothly. Furthermore, the second lubricating oil circulating through the second lubricating oil circulation passage enables the camshaft, the intake valve, and the exhaust valve to operate smoothly.
As described above, the camshaft storage space is independent from the recess (the combustion chamber) of the cylinder head, the inlet port, and the exhaust port. Additionally, the chain cover adjacent wall of the cylinder head separates the camshaft storage space from the chain storage space in an air-tight and water-tight manner.
Therefore, the first lubricating oil circulation passage and the second lubricating oil circulation passage are independent from each other. In other words, the first lubricating oil does not flow into the second lubricating oil circulation passage and the second lubricating oil does not flow into the first lubricating oil circulation passage.
By the way, when the internal combustion engine operates, so-called blowby gas is generated in the combustion chamber. This blowby gas flows through the gap between the inner circumferential surface of the cylinder bore and the end gap of the piston ring attached to the piston, and flows into the crank shaft storage space. The blowby gas comes in contact with the first lubricating oil, and then the first lubricating oil deteriorates. Then, the first lubricating oil needs to be replaced with new lubricating oil with a certain frequency.
On the other hand, the recess (the combustion chamber) and the camshaft storage space are independent from each other. Then, the blowby gas does not flow into the camshaft storage space to come into contact with the second lubricating oil.
Additionally, since the chain cover adjacent wall separates the camshaft storage space from the chain storage space in an air-tight and water-tight manner, the blowby gas does not flow into the camshaft storage space from the chain storage space to come into contact with the second lubricating oil.
Therefore, the second lubricating oil is harder to deteriorate than the first lubricating oil. Then, the exchange frequency of the second lubricating oil with new lubricating oil is lower than that of the first lubricating oil.
It should be noted that Japanese Unexamined Patent Application Publication No. H08-246831 and Japanese Unexamined Patent Application Publication No. 2011-190721 disclose a background technology related to the present invention.
Typically, a plurality of portions of the lower half portion of the camshaft, which are separated from each other in the axial direction of the camshaft, are rotatably supported by a plurality of journal bearings, which are disposed inside the cylinder head along the axial direction thereof, respectively.
Furthermore, a plurality of cam caps, which are disposed in the camshaft storage space, are mounted on a plurality of portions of the upper half portion of the camshaft, which are separated from each other in the axial direction, from above, respectively. Each of the cam caps rotatably supports the upper half portion of the camshaft. In addition, each of the cam caps is fixed to corresponding one of journal bearings.
The cam cap positioned on the most chain cover adjacent wall side is disposed in the camshaft storage space so as to be close to the inner surface (the side surface that defines the camshaft storage space) of the chain cover adjacent wall.
Incidentally, the axial direction dimension of the camshaft storage space (i.e., the cylinder head) is the dimension including the thickness of the chain cover adjacent wall and the thickness of all the cam caps.
Then, the internal combustion engine having the above structure, in which the chain cover adjacent wall and all the cam caps are arranged in the axial direction, has difficulty in reducing both the axial direction dimension of the cylinder head and the axial direction dimension of the entire internal combustion engine.
The present invention has been made to cope with the above problems, and has an object to provide an internal combustion engine that can securely prevent the first lubricating oil circulation passage and the second lubricating oil circulation passage from communicating with each other between the camshaft storage space and the chain storage space, and can reduce the dimension of the entire internal combustion engine in the axial direction of the camshaft.
In order to achieve the object, an internal combustion engine comprises:
a cylinder block (20) including a cylinder bore (21) which supports a piston (23) so as to be slidable;
an oil pan (30) provided therein with a crank shaft storage space (32) for storing a crank shaft (25) rotating in conjunction with an operation of the piston, the oil pan connected to the cylinder block;
a cylinder head (35) provided therein with a port (42, 43), which is communicated with the cylinder bore and made to be opened and closed by a valve (44, 45) reciprocating in conjunction with the operation of the piston, a sub oil pan (40a), and a camshaft storage space (47a), which has no communication with an interior of the oil pan, the crank shaft storage space, and the cylinder bore;
a camshaft (65, 70) disposed in the camshaft storage space, the camshaft including a plurality of supported portions (66, 71) whose lower portions are rotatably supported by the cylinder head so that the camshaft rotates about its own axis to reciprocate the valve, the supported portions arranged at an interval in an axial direction of the camshaft;
a plurality of cam caps (75, 80), fixed to the cylinder head, for rotatably supporting upper portions of the supported portions of the camshaft;
a cover member (88) connected to the oil pan and the cylinder head so that the cover member is provided therein with an interlocking member storage space (89), the interlocking member storage space storing an annular interlocking member (86) interlocking the crank shaft and the camshaft, the interlocking member storage space having communication with the crank shaft storage space and having no communication with the camshaft storage space;
a first lubricating oil (91) filled in the oil pan so as to circulate through the interior of the oil pan, the crank shaft storage space, the cylinder bore and the interlocking member storage space;
a second lubricating oil (101) filled in the sub oil pan so as to circulate through the an interior of the sub oil pan and the camshaft storage space; and
a cover adjacent wall (48) for forming part of the cylinder head and for separating the interlocking member storage space from the camshaft storage space.
Atmosphere pressure of the interlocking member storage space is kept lower than atmosphere pressure of the camshaft storage space.
A recess for cam cap (51) is formed on an upper end surface of the cover adjacent wall so as to penetrate through the cover adjacent wall in the axial direction of the camshaft.
One of the plurality of the cam caps, which is disposed in the recess for cam cap and is located closest to the cover member among the cam caps, is an end cam cap (80).
The end cam cap is provided with a pair of side surfaces which are spaced from each other in a direction orthogonal to the axial direction.
The side surfaces of the end cam cap and a pair of side surfaces (51b) of the recess for cam cap form two cross-sectional area gradually changing gaps (S) therebetween. Each of the cross-sectional area gradually changing gaps has both open ends which are separated from each other in the axial direction and each of the cross-sectional area gradually changing gaps has a cross-sectional area which gradually decreases as approaching to the interlocking member storage space from an intermediate portion thereof in the axial direction or a portion thereof farther from the interlocking member storage space than the intermediate portion in the axial direction.
A gasket (G) is filled between an inner surface of the recess for cam cap and an outer surface of the end cam cap. The inner surface includes the side surfaces of the recess for cam cap and the outer surface includes the side surfaces of the end cam cap.
In the internal combustion engine of the present invention, the end cam cap is disposed in the recess for cam cap formed on the upper end surface of the cover adjacent wall of the cylinder head. Namely, the cover adjacent wall and the end cam cap are disposed at the same position in the axial direction of the camshaft.
Therefore, compared with a conventional internal combustion engine, the present invention can reduce both the dimension of the cylinder head and the dimension of the entire internal combustion engine in the axial direction of the camshaft.
Furthermore, since an atmosphere pressure of the interlocking member storage space is lower than an atmosphere pressure of the camshaft storage space, the second lubricating oil in the camshaft storage space always attempt to flow into the interlocking member storage space via a gap between the recess for cam cap and the end cam cap.
However, a semi-solidified gasket is filled in the gap between the outer surface of the cam cap and the inner surface of the recess for cam cap.
Therefore, the second lubricating oil does not leak to the interlocking member storage space via the gap between the recess for cam cap and the end cam cap, and thus does not mix with the first lubricating oil.
Therefore, the second lubricating oil does not decrease.
Furthermore, gaps need to be formed between both side surfaces of the end cam cap and both side surfaces of the recess for cam cap in order to dispose the end cam cap in the recess for cam cap. In other words, the dimension between the both side surfaces of the end cam cap needs to be smaller than the dimension between the both side surfaces of the recess for cam cap.
In the present invention, the cross-sectional area gradually changing gaps, each of which has both open ends separated from each other in the axial direction and has a cross-sectional area gradually decreasing as approaching to the interlocking member storage space from the intermediate portion thereof in the axial direction or the portion thereof farther from the interlocking member storage space than the intermediate portion in the axial direction, are formed between both side surfaces of the end cam cap and both side surfaces of the recess for cam cap.
Since the atmosphere pressure of the interlocking member storage space is lower than the atmosphere pressure of the camshaft storage space, a pressure is applied from the camshaft storage space to the gasket that is semi-solidified in this cross-sectional area gradually changing gap.
However, the cross-sectional area of the interlocking member storage space side end of the cross-sectional area gradually changing gap is smaller than the cross-sectional area of the intermediate portion of the cross-sectional area gradually changing gap. Then, the interlocking member storage space side end of the cross-sectional area gradually changing gap generates a large resistance force to prevent the gasket from moving to the interlocking member storage space.
Therefore, the gasket hardly discharged to the interlocking member storage space via the cross-sectional area gradually changing gap.
Therefore, a chance that the second lubricating oil filled in the camshaft storage space of the cylinder head leaks to the interlocking member storage space via the cross-sectional area gradually changing gap is much smaller compared with the case where the side surfaces of the recess for cam cap and the side surfaces of the end cam cap are flat surfaces parallel to each other.
An interlocking member storage space side end of each of the cross-sectional area gradually changing gaps may be located closer to the camshaft storage space than an interlocking member storage space side surface of the cover adjacent wall.
The side surfaces of the end cam cap and the side surfaces of the recess for cam cap may be flat surfaces.
Each of the side surfaces of the end cam cap and each of the side surfaces of the recess for cam cap may face each other so as to form a minute gap therebetween and be parallel to each other at a position between each of the cross-sectional area gradually changing gaps and the interlocking member storage space.
This “parallel” includes not only “complete parallel” but also “substantially parallel”.
Between the interlocking member storage space side end of the cross-sectional area gradually changing gap and the interlocking member storage space side surface of the cover adjacent wall, the side flat surfaces of the end cam cap and the side flat surfaces of the recess for cam cap surface face with each other so as to form the minute gaps therebetween and be parallel to each other.
Therefore, a chance that the gasket is discharged to the interlocking member storage space via the cross-sectional area gradually changing gap become much smaller compared with the case where the interlocking member storage space side end of the cross-sectional area gradually changing gap is positioned at the same position as the interlocking member storage space side surface of the cover adjacent wall. Namely, the chance that the second lubricating oil leaks to the interlocking member storage space via the cross-sectional area gradually changing gap becomes much smaller.
A bottom surface (51a) of the recess for cam cap and a bottom surface of the end cam cap may be horizontal flat surfaces.
If the cross-sectional area gradually changing gap is formed between the bottom surface of the end cam cap and the bottom surface of the recess for cam cap and the gasket is filled in this cross-sectional area gradually changing gap, the bottom surface of the recess for cam cap supports the end cam cap unstably.
However, when the present invention is configured in this way, the supporting state of the end cam cap by the bottom surface of the recess for cam cap can become stable.
A cutout may be formed on each of the side surfaces of the end cam cap.
Each of the cutouts and each of the side surfaces of the recess for cam cap may form the cross-sectional area gradually changing gap therebetween when the end cam cap is disposed in the recess for cam cap.
The cutout for forming the cross-sectional area gradually changing gap between the side surfaces of the end cam cap and the side surfaces of the recess for cam cap can be easily formed on the side surfaces of the end cam cap than the side surfaces of the recess for cam cap.
Therefore, when the present invention is configured in this way, the productivity of the internal combustion engine can be increased.
In the above description, references used in the following descriptions regarding embodiments are added with parentheses to the elements of the present invention, in order to understand the invention. However, those references should not be used to limit the scope of the present invention.
Other objects, other features, and accompanying advantages of the present invention are easily understood from the description of embodiments of the present invention to be given referring to the following drawings.
An internal combustion engine of the present invention will be described hereinafter with reference to the accompanying figures.
This internal combustion engine 10 is provided with a cylinder block 20, an oil pan 30, a cylinder head body 40, a camshaft housing 47, an intake system 60, an exhaust system 61, an exhaust camshaft 65, an intake camshaft 70, a cam cap 75, an end cam cap 80, a timing chain 86, a cylinder head cover 87, a cover member 88, a first lubricating oil circulation system 90, a second lubricating oil circulation system 100, a fresh air inlet pipe 108, and a blowby gas circulation pipe 109, as main components.
As shown in
The upper portion of the connecting rod 24 is rotatably connected to the piston 23.
The upper surface of the oil pan 30 is in contact with the lower surface of the cylinder block 20 in an air-tight and water-tight manner. The cylinder block 20 and the oil pan 30 are fixed with each other by using a bolt and a nut. As shown in
A crankshaft bearing (not shown) provided at the bottom of the cylinder block 20 rotatably supports a crank shaft 25 extending in the forward and rearward direction. Furthermore, the lower end portion of the connecting rod 24 is rotatably connected to the connecting rod bearing (not shown) formed in the crank shaft 25. A sprocket (not shown) is fixed to the front portion of the crank shaft 25.
The interior space of the oil pan 30 constitutes a first lubricating oil storage room 31. Furthermore, the lower space 22 of the cylinder block 20 and the first lubricating oil storage room 31 of the oil pan 30 constitute a crank shaft storage space 32 communicating with the cylinder bore 21.
A cylinder head 35 is fixed to the upper end portion of the cylinder block 20. The cylinder head 35 is provided with the cylinder head body 40 and the camshaft housing 47.
The lower end surface of the cylinder head body 40 is in contact with the upper end surface of the cylinder block 20 in an air-tight and water-tight manner. The cylinder head body 40 and the cylinder block 20 are fixed to each other by using a bolt. As shown in
As shown in
Furthermore, an inlet port 42 and an exhaust port 43, both of which communicate with the combustion chamber 41, are formed in the cylinder head body 40. In addition, an intake valve guide 42a and an exhaust valve guide 43a, both of which have cylindrical shapes, are fixed to the cylinder head body 40. The lower end of the intake valve guide 42a is connected to the inlet port 42, and the lower end of the exhaust valve guide 43a is connected to the exhaust port 43. Further, cylindrical seal members (not shown) are fixed to the upper portion of each intake valve guide 42a and the upper portion of each exhaust valve guide 43a, respectively. An intake valve 44 and an exhaust valve 45 are inserted into each intake valve guide 42a and each exhaust valve guide 43a, respectively. The intake valve 44 and the exhaust valve 45 are movable in the axial direction of the intake valve guide 42a and the axial direction of the exhaust valve guide 43a, respectively. A stem portion of each of the intake valves 44 is slidably supported by each intake valve guide 42a and a stem portion of each of the exhaust valves 45 is slidably supported by each exhaust valve guide 43a. As is well known, each of the intake valves 44 and each of the exhaust valves 45 open and close the corresponding inlet port 42 and the corresponding exhaust port 43 respectively by reciprocating in the axial direction of the intake valve guide 42a and the axial direction of the exhaust valve guide 43a, respectively.
An ignition plug 46a, an igniter 46b that generates a high voltage given to the ignition plug 46a, and an injector 46c that injects the fuel into the inlet port 42 are provided inside the cylinder head body 40.
The camshaft housing 47 is provided on the upper end surface of the cylinder head body 40.
As shown in
The camshaft housing 47 includes a chain cover adjacent wall 48, a pair of the side walls 49, and a rear wall 50 (see
A camshaft storage space 47a, whose top is opened, is formed inside the camshaft housing 47.
The camshaft storage space 47a is independent from the recess (the combustion chamber 41) formed at the bottom of the cylinder head body 40. In other words, the camshaft storage space 47a and this combustion chamber 41 do not communicate with each other. Since each seal member is fixed to the upper portion of each of the intake valve guides 42a and the upper portion of each of the exhaust valve guides 43a respectively, the camshaft storage space 47a is independent from each of the inlet ports 42 and each of the exhaust ports 43. Namely, the camshaft storage space 47a dose not communicate with the inlet ports 42 and the exhaust ports 43.
As shown in
The bottom surface 51a of the recess for cam cap 51 is a horizontal flat surface. The left and right side surfaces 51b of the recess for cam cap 51 are flat surfaces that are parallel to each other and are orthogonal to the lateral direction (left and right direction).
A pair of left and right bearing recesses 52a, 52b are formed on the bottom surface 51a. The cross-sectional shape of the left bearing recess 52a and the cross-sectional shape of the right bearing recess 52b are semicircular shapes, which are the same as each other, respectively. Four female screw holes 53 are formed on the bottom surface 51a of the recess for cam cap 51 so as to separate from the bearing recesses 52a, 52b.
Furthermore, the camshaft housing 47 is provided integrally with a plurality of journal bearings 56 that are arranged at approximately equal intervals in the forward and rearward direction. The upper end surface of each journal bearing 56 is a flat surface located on a plane on which the bottom surface 51a of the recess for cam cap 51 is located.
A pair of left and right bearing recesses 57a, 57b, each of which has a semicircular shaped cross-section, are formed on the upper surface of each of the journal bearings 56. Furthermore, each of the bearing recesses 57a is coaxial with the bearing recess 52a, and each of the bearing recesses 57b is coaxial with the bearing recess 52b. Four female screw holes 58 are formed on the upper end surface of each of the journal bearings 56 so as to separate from the bearing recesses 57a, 57b.
As shown in
The intake system 60 is provided with an intake manifold 60a connected to the upstream end of each inlet port 42, a surge tank 60b connected to the intake manifold 60a, a throttle body connected to the surge tank 60b, and an intake duct 60c connected to the throttle body. The throttle body is provided integrally with a throttle valve 60d and an actuator for throttle valve 60e.
The exhaust system 61 comprises an exhaust pipe 61b, which includes an exhaust manifold 61a communicating with the downstream end of each exhaust port 43, and a catalyst apparatus 61c, which is arranged in the exhaust pipe 61b.
As shown in
The exhaust camshaft 65 and the intake camshaft 70 are elongated members whose axes extend in the forward and rearward direction. The exhaust camshaft 65 and the intake camshaft 70 have the supported portions 66 and the supported portions 71, respectively. The number of the supported portions 66 and the number of the supported portions 71 are the same as the total number of the chain cover adjacent wall 48 and all the journal bearings 56. Each of the outer peripheral surfaces of the supported portions 66, 71 is a cylindrical surface that has the same curvature as that of corresponding one of the bearing recesses 52a, 52b, 57a, 57b, respectively. Furthermore, the exhaust camshaft 65 has multiple pairs of the cams 67 formed at different positions from the supported portions 66. Likewise, the intake camshaft 70 has multiple pairs of the cams 72 formed at different positions from the supported portions 71. Furthermore, sprockets 68, 73 are fixed to the vicinity of the front end of the exhaust camshaft 65 and the vicinity of the front end of the intake camshaft 70, respectively.
The lower half portion of the foremost supported portion 66 of the exhaust camshaft 65 and the lower half portion of the foremost supported portion 71 of the intake camshaft 70 are supported by the bearing recess 52a and the bearing recess 52b of the camshaft housing 47, respectively. On the other hand, the lower half portions of the remaining supported portions 66 of the exhaust camshaft 65 are rotatably supported by each of the bearing recesses 57a of the journal bearings 56, respectively, and the lower half portions of the remaining supported portions 71 of the intake camshaft 70 are rotatably supported by each of the bearing recesses 57b of the journal bearings 56, respectively. Furthermore, the sprocket 68 of the exhaust camshaft 65 and the sprocket 73 of the intake camshaft 70 are located at a more forward position than the chain cover adjacent wall 48 of the camshaft housing 47.
Further, a VVT 74 (variable valve timing mechanism) is provided at the front end portion of each of the exhaust camshaft 65 and the intake camshaft 70, respectively (see
The cam caps 75 are mounted on the upper end surface of each of the journal bearings 56 of the camshaft housing 47 from above, respectively.
Each of the cam caps 75 is a plate material that has a substantially rectangular shape in the front view, and its lateral dimension (a dimension in the left and right direction) is shorter than the lateral dimension between the inner surfaces of the left and right side walls 49 of the camshaft housing 47. Further, a pair of left and right bearing recesses 76a, 76b are formed on the bottom surface of each of the cam caps 75. The cross-sectional shapes of the bearing recesses 76a, 76b are semicircular shapes that are vertically symmetrical with the bearing recesses 57a, 57b. In addition, four through-holes 77 are formed in each of the cam caps 75 so as to be at positions different from those of the bearing recesses 57a, 57b. Each of the through-holes 77 penetrates through the cam caps 75 in the vertical direction.
The lower surface of each of the cam caps 75 are in contact with the corresponding one of upper surfaces of the journal bearings 56. Furthermore, each of the cam caps 75 is fixed to corresponding one of the journal bearings 56 by screwing the lower end of each of bolts (not shown), which are inserted into through-holes 77 of each journal bearing 56 from above, into corresponding one of the female screw holes 58.
The bearing recess 76a of each cam cap 75 rotatably supports the upper half portion of corresponding one of the supported portions 66 of the exhaust camshaft 65, respectively. Likewise, the bearing recess 76b of each cam cap 75 rotatably supports the upper half portion of corresponding one of the supported portions 71 of the intake camshaft 70, respectively.
The end cam cap 80 is detachably mounted to the recess for cam cap 51 of the camshaft housing 47.
The dimension in the forward and rearward direction of the end cam cap 80 is the same as that of the recess for cam cap 51. The vertical dimension of the end cam cap 80 is the same as that of the recess for cam cap 51. However, the dimension in the forward and rearward direction of the end cam cap 80 does not have to be the same as that of the recess for cam cap 51 as long as the vertical dimensions of the left and right ends of the end cam cap 80 are the same as that of the recess for cam cap 51. On the other hand, the lateral dimension of the end cam cap 80 is slightly smaller than that of the recess for cam cap 51.
The six surfaces that form the entire outer surface of the end cam cap 80 are flat surfaces. Furthermore, the upper surface and the lower surface of the end cam cap 80 are horizontal flat planes. However, the entire outer surface excluding the lower surface of the end cam cap 80 does not have to be a flat surface (flat surfaces) while the lower surface of the end cam cap 80 must be a flat surface.
A pair of left and right bearing recesses 81a, 81b are formed on the bottom surface of the end cam cap 80. The cross-sectional shapes of the bearing recesses 81a, 81b are semicircular shapes that are vertically symmetrical with the bearing recesses 52a, 52b, respectively. Four through-holes 82 are formed in the end cam cap 80 so as to be at positions different from those of the bearing recesses 81a, 81b. Each of the through-holes 82 penetrates through the end cam cap 80 in the vertical direction.
The end cam cap 80 has a pair of left and right side surfaces that are spaced apart from each other in a direction orthogonal to the axial directions of the exhaust camshaft 65 and the intake camshaft 70. As shown in
Likewise, although not shown, the left side portion of the end cam cap 80 is constituted by a gap forming surface 83 that is bilaterally symmetrical with this right side gap forming surface 83. In other words, the left side portion of the end cam cap 80 is cut out (notched) so as to form this gap forming surface 83.
Pasty gasket G, which is called FIPG (Formed In Place Gasket) and is an oil resistant sealing material, is applied to the entire bottom surface of the end cam cap 80, the entire left gap forming surface 83 of the end cam cap 80, and the entire right gap forming surface 83 of the end cam cap 80. Specific example of this gasket G is a gasket that includes a room temperature vulcanizing silicone rubber which is paste and contains a base silicone oil, a cross-linking agent, a filler, and an adhesion imparting agent. This gasket G is pasty when it is placed in a tube (container) not shown (namely, when it is not in contact with the air). Further, the gasket G is turned into semi-solidified with the lapse of time when it comes into contact with the air. The end cam cap 80 to which the gasket G is applied is fitted into the recess for cam cap 51. Since the lateral dimension of the end cam cap 80 is slightly smaller than that of the recess for cam cap 51, the end cam cap 80 can be smoothly fitted into the recess for cam cap 51.
Furthermore, bolts (not shown) are inserted into each of the through-holes 82 of the end cam cap 80 from above, and the lower end of each of bolts is screwed into each of the female screw holes 53 formed in the recess for cam cap 51.
The end cam cap 80 is thus fixed to the recess for cam cap 51. As a result, the upper surface (at least the upper surfaces of the left and right end portions) of the end cam cap 80 is located on a flat (plane) on which the upper surface of the camshaft housing 47 is located.
When the end cam cap 80 is fixed to the recess for cam cap 51, the bearing recess 81a and the bearing recess 52a rotatably support the foremost supported portion 66 of the exhaust camshaft 65. Likewise, the bearing recess 81b and the bearing recess 52b rotatably support the foremost supported portion 71 of the intake camshaft 70. Then, the exhaust camshaft 65 and the intake camshaft 70 are allowed to rotate relative to the camshaft housing 47 about their own axes.
Further, as shown in
At the moment when the gasket G is applied to the end cam cap 80, the gasket G is pasty. However, the gasket G is turned into semi-solidified gradually with the lapse of time. When a certain period of time elapses after the end cam cap 80 is fitted into the recess for cam cap 51, the left and right gap forming surfaces 83 and the bottom surface of the end cam cap 80 and the inner surface of the recess for cam cap 51 are fixed to each other by the semi-solidified gasket G.
The space between both side surfaces and the bottom surface of the end cam cap 80 and the inner surface of the recess for cam cap 51 is filled with the semi-solidified gasket G. Namely, the semi-solidified the gasket G comes into contact with the left and right gap forming surfaces 83, the bottom surface of the end cam cap 80, and the inner surface of the recess for cam cap 51 in an air-tight and water-tight manner. Furthermore, a portion of the gasket G, which is semi-solidified between the bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51, and another portions of the gasket G, which are semi-solidified between the left and right gap forming surfaces 83 of the end cam cap 80 and the left and right surfaces 51b of the recess for cam cap 51, are continuous with each other.
As shown in
As shown in
As shown in
Thus, the camshaft storage space 47a of the camshaft housing 47 and the interior space of the cylinder head cover 87 communicate with each other. These spaces have no communication with the external space outside of the cylinder head body 40, the camshaft housing 47, and the cylinder head cover 87. Therefore, the atmosphere pressure of each of the camshaft storage space 47a of the camshaft housing 47 and the atmosphere pressure of the interior space of the cylinder head cover 87 are always the same as the outside air pressure (the atmospheric pressure outside of the vehicle).
Further, as shown in
The rear surface and the bottom surface of the cover member 88 are only opened in the cover member 88.
The chain storage space 89 is formed inside the cover member 88 (see
The lower end portion of the cover member 88 is connected to the upper end surface of the front portion of the oil pan 30. Namely, the lower end of the chain storage space 89 and the front end portion of the first lubricating oil storage room 31 (the crank shaft storage space 32) communicate with each other.
As shown in
As shown in
The first lubricating oil storage room 31 of the oil pan 30 is always filled with the first lubricating oil 91.
The oil strainer 93, the oil pump 94 and the oil filter 96 are disposed in the cylinder block 20. The oil strainer 93, the oil pump 94 and the oil filter 96 are connected to each other via oil paths (not shown). The oil strainer 93 is in contact with the first lubricating oil 91 in the first lubricating oil storage room 31. The oil pump 94 is interlocked with the crank shaft 25 via members including a chain (not shown). The oil pump 94 is provided integrally with the relief valve 95.
The main gallery 92 is connected to each of the crankshaft bearings and the piston jet 97. This piston jet 97 is provided in the cylinder block 20 so as to be close to the cylinder bore 21 and the piston 23. Further, the main gallery 92 is connected to the chain jet 98. This chain jet 98 is fixed to the cylinder head body 40 or the cylinder block 20. The chain jet 98 is exposed in the chain storage space 89 and is close to the timing chain 86.
As shown in
The cylinder head body 40 is provided with the sub oil pan 40a that is a recess formed inside the cylinder head body 40. This the sub oil pan 40a is always filled with the second lubricating oil 101.
The sub oil strainer 102, the sub oil pump 103 and the sub oil filter 105 are provided inside the cylinder head body 40. The sub oil pump 103 is interlocked with the crank shaft 25 via the exhaust camshaft 65, the intake camshaft 70 and the chain or the like, and is provide integrally with the relief valve 104. Note that, the sub oil pump 103 may be an electric pump.
The sub oil strainer 102, the sub oil pump 103 and the sub oil filter 105 are connected to each other via the lubricating oil passage 107 formed inside the cylinder head body 40. The sub oil strainer 102 is in contact with the second lubricating oil 101 in the sub oil pan 40a.
Furthermore, the lubricating oil passage 107 is connected to grooves (not shown) formed on the inner surfaces of the bearing recesses 52a, 52b of the chain cover adjacent wall 48. An oil passage for VVT (not shown) is formed inside the front portion of each of the exhaust camshaft 65 and the intake camshaft 70. Furthermore, the entrance end of each oil passage for VVT is formed on the surface of each of the foremost supported portions 66, 71 of the exhaust camshaft 65 and the intake camshaft 70. Each oil passage for VVT passes through the corresponding VVT 74, and further is connected to the front end of each oil passage 48a (see
Furthermore, as shown in
One end of the fresh air inlet pipe 108 is connected to the cover member 88, and the other end of the fresh air inlet pipe 108 is connected to the intake system 60 at a position upstream of the throttle valve 60d.
One end of the blowby gas circulation pipe 109 is connected to the cylinder block 20, and the other end of the blowby gas circulation pipe 109 is connected to the intake system 60 at a position downstream of throttle valve 60d. A valve (not shown) is provided in the blowby gas circulation pipe 109.
Further, as shown in
The crank position sensor CS outputs signal every time the crank shaft 25 rotates by a predetermined angle. This signal is used to obtain rotating speed NE of the internal combustion engine 10. The rotating speed NE represents the number of rotations of the crank shaft 25 per minute.
The wheel speed sensor outputs a signal representing a rotating speed of each wheel of the vehicle. A vehicle speed SPD is acquired based on average value of the rotating speeds of the wheels.
The accelerator opening sensor APS detects an operation amount of the accelerator pedal AP operated by a driver and outputs a signal representing this operation amount.
The break sensor BPS detects an operation amount of the brake pedal BP operated by the driver and outputs a signal representing this operation amount.
The electronic control unit 110 (hereinafter it is referred to as ECU 110) is a micro-computer including a CPU 111, a ROM 112, a RAM 113, a backup RAM 114 and an interface 115, all of which are connected to each other via a bus. Data, which includes a program executed by the CPU 111, a look-up table (a map), and constants, are stored in the ROM 112 in advance so that the data are held. The RAM 113 temporarily holds data according to the instruction from the CPU 111. The backup RAM 114 holds data not only when the internal combustion engine 10 is in the driving state but also when the internal combustion engine 10 is not in the driving state. The interface 115 includes an AD converter.
The interface 115 is connected to an ignition switch (not shown), the crank position sensor CS, the wheel speed sensor, the accelerator opening sensor APS, and the break sensor BPS. Output signals of the ignition switch, the crank position sensor CS, the wheel speed sensor, the accelerator opening sensor APS, and the break sensor BPS are transmitted to the CPU 111. As is well known, the ignition switch can be switched to any one of an OFF position, an ON position and an accessory position by operating a key (not shown).
Next, the operation of the internal combustion engine 10 in accordance with the control of the ECU 110 will be described.
When the ignition switch is operated by operation of the key, the internal combustion engine 10 starts to rotate. Then, the CPU 111 sends a driving signal (instruction signal) to the igniter 46b, the injector 46c, the actuator for throttle valve 60e, and the actuator for VVT.
Then, an air-fuel mixture including the fuel and air is supplied from the intake system 60 to the combustion chamber 41, and this air-fuel mixture burns in the combustion chamber 41. Then, each piston 23 reciprocates in the vertical direction in the corresponding cylinder bore 21 of the cylinder block 20. Then, the movement of each piston 23 is transmitted to the crank shaft 25 through the connecting rod 24, and then the crank shaft 25 rotates about its axis. Then, since rotational force of the crank shaft 25 is transmitted to the sprocket 68 of the exhaust camshaft 65 and the sprocket 73 of the intake camshaft 70 through the timing chain 86, each of the exhaust camshaft 65 and the intake camshaft 70 rotates about its own axis. As a result, each cam 67 of the exhaust camshaft 65 rotates to move corresponding one of the rocker arms 84 upward and downward. Then, each exhaust valve 45 connected to corresponding one of the rocker arms 84 moves upward and downward to open and close each exhaust port 43. Additionally, each cam 72 of the intake camshaft 70 rotates to move corresponding one of the rocker arms 84 upward and downward. Then, each intake valve 44 connected to corresponding one of these rocker arms 84 moves upward and downward to open and close each inlet port 42.
When the CPU 111 sends a driving signal to the actuator for VVT connected to the VVT 74 provided in the exhaust camshaft 65, the driving force of the actuator for VVT causes the rotation position of the exhaust camshaft 65 (rotation phase) to change with respect to the crank shaft 25. Therefore, the valve timing (INVT) of each of the exhaust valves 45 changes to the advance angle side or the delay angle side. Likewise, when the CPU 111 sends a driving signal to the actuator for VVT connected to the VVT 74 provided in the intake camshaft 70, the driving force of this actuator for VVT causes the rotation position of the intake camshaft 70 to change with respect to the crank shaft 25. Therefore, the valve timing of each of the intake valves 44 changes to the advance angle side or the delay angle side.
Furthermore, when the crank shaft 25 rotates, this rotational force is transmitted to the oil pump 94 and the sub oil pump 103 via members including the chain, and then the oil pump 94 and the sub oil pump 103 start their suction operation.
As shown in
In addition, the first lubricating oil 91 is supplied from the main gallery 92 to the crankshaft bearing. Part of the first lubricating oil 91 supplied to the crankshaft bearing returns to the oil pan 30 by gravity. The remaining first lubricating oil 91 supplied to the crankshaft bearing is supplied to the connecting rod bearing of the crank shaft 25 and returns to the oil pan 30 by gravity.
In addition, part of the first lubricating oil 91 is supplied from the main gallery 92 to the piston jet 97. Then, the piston jet 97 injects the first lubricating oil 91 to the cylinder bore 21 and the piston 23. The first lubricating oil 91 fed to the cylinder bore 21 and the piston 23 returns to the oil pan 30 by gravity.
In this way, the first lubricating oil 91 circulates through the first lubricating oil storage room 31 of the oil pan 30 and the interior space of the cylinder block 20 by the sucking force of the oil pump 94. The circulation passage of this first lubricating oil 91 is a block side first lubricating oil circulation passage 90a shown in
Further, the first lubricating oil 91 flowing into the main gallery 92 is supplied from the main gallery 92 to the chain jet 98. Then, the chain jet 98 injects the first lubricating oil 91 to the timing chain 86. The first lubricating oil 91 supplied to the timing chain 86 returns to the oil pan 30 by gravity.
In this way, the first lubricating oil 91 in the first lubricating oil storage room 31 of the oil pan 30 circulates through the inside space of the oil pan 30, the inside space of the cylinder block 20, and the chain storage space 89 of cover member 88 by the sucking force of the oil pump 94. The circulation passage of this first lubricating oil 91 is a chain side first lubricating oil circulation passage 90b shown in
On the other hand, as shown in
The second lubricating oil 101, which has lubricated the interior of each VVT 74, passes through the oil passage 48a of the chain cover adjacent wall 48 and returns to the sub oil pan 40a by gravity.
The second lubricating oil 101 supplied to the HLA gallery 106 is supplied to the HLA 85 through the HLA gallery 106. Furthermore, part of the second lubricating oil 101 supplied to the HLA 85 returns to the sub oil pan 40a by gravity. In addition, part of the second lubricating oil 101 supplied to the HLA gallery 106 is supplied to the inner surfaces of the bearing recesses 57a, 57b of each of the bearing journals 56 through the HLA gallery 106.
Part of the second lubricating oil 101 supplied to the journal bearings 56 returns to the sub oil pan 40a by gravity. The remaining second lubricating oil 101 supplied to the journal bearings 56 is supplied to the rocker arms 84. Furthermore, the second lubricating oil 101 supplied to the rocker arms 84 returns to the sub oil pan 40a by gravity.
In this way, the second lubricating oil 101 in the sub oil pan 40a circulates through the interior of the camshaft housing 47 and the interior of the cylinder head cover 87 by the sucking force of the sub oil pump 103. The circulation passage of this second lubricating oil 101 is a second lubricating oil circulation passage 100a shown in
As is well known, when the internal combustion engine 10 is in an operation state, part of the combustion gas generated in the combustion chamber 41 flows into the crank shaft storage space 32 after passing through a gap between the inner peripheral surface of the cylinder bore 21 and the piston ring end gaps of piston rings, which are mounted on each of the pistons 23 respectively, to become blowby gas.
Then, the blowby gas comes into contact with the first lubricating oil 91 in the first lubricating oil storage room 31 of the oil pan 30. As a result, since the blowby gas is mixed with the first lubricating oil 91, the first lubricating oil 91 is deteriorated.
On the other hand, as described above, the camshaft storage space 47a of the camshaft housing 47 and the recess (the combustion chamber 41) of the cylinder head body 40 have no communication with each other. Furthermore, the seal members, which are fixed to the upper portion of each of the intake valve guides 42a and the exhaust valve guides 43a respectively, cause the inlet ports 42 and the exhaust ports 43 not to communicate with the camshaft storage space 47a.
Therefore, the blowby gas staying in the cylinder block 20 and the oil pan 30 does not flow into the camshaft housing 47 via the recess (the combustion chamber 41), each intake valve guide 42a and each exhaust valve guide 43a. Namely, the blowby gas does not come in contact with the second lubricating oil 101 disposed inside the camshaft housing 47 and the cylinder head cover 87 via the combustion chamber 41, the intake valve guide 42a, and the exhaust valve guide 43a.
In addition, the second lubricating oil 101 in the camshaft housing 47 does not flow into the cylinder block 20 and the oil pan 30 via the combustion chamber 41, the intake valve guide 42a, and the exhaust valve guide 43a. Namely, the second lubricating oil circulation passage 100a and the block side first lubricating oil circulation passage 90a (and the chain side first lubricating oil circulation passage 90b) are independent from each other.
By the way, the blowby gas in the crank shaft storage space 32 and the chain storage space 89 flows into the combustion chamber 41 via the blowby gas circulation pipe 109 and the intake system 60a to be burned in the combustion chamber 41.
On the other hand, fresh air (which excludes exhaust gas and fuel) flowing from the upstream side of the intake duct 60c to the downstream side of the intake duct 60c is always supplied to the chain storage space 89 and the crank shaft storage space 32 via the fresh air inlet pipe 108.
Thus, a negative pressure is always applied to the chain storage space 89 of the cover member 88 and the inside of the cylinder block 20. Therefore, the atmosphere pressure of the chain storage space 89 is always lower than those of the camshaft storage space 47a of the camshaft housing 47 and the interior space of the cylinder head cover 87 (i.e., the outside air pressure or the atmospheric pressure outside of the vehicle). Since there is a difference in atmosphere pressure between the camshaft storage space 47a of the camshaft housing 47 and the chain storage space 89, if there is a gap that makes the camshaft storage space 47a and the chain storage space 89 communicate with each other therebetween, a sucking force heading to the chain storage space 89 is always applied to the second lubricating oil 101.
However, the spaces (the cross-sectional area gradually changing gaps S) between the left and right gap forming surfaces 83 of the end cam cap 80 and the left and right side surfaces 51b of the recess for cam cap 51 are filled with the gasket G in an air-tight and water-tight manner. Furthermore, the space between the bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51 is also filled with the gasket G in an air-tight and water-tight manner.
Then, the second lubricating oil 101 in the camshaft storage space 47a does not pass through a gap between the end cam cap 80 and the recess for cam cap 51 to leak to the chain storage space 89. Then, the second lubricating oil 101 in the camshaft storage space 47a does not mix with the first lubricating oil 91.
Then, the second lubricating oil 101 in the camshaft storage space 47a does not decrease.
The bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51 are substantially parallel to each other. In other words, the cross-sectional area of the gap between the bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51 is substantially constant at any position in the forward and rearward direction. Namely, the cross-sectional area of the gap between the front end portion of the bottom surface of the end cam cap 80 and the front end portion of the bottom surface 51a of the recess for cam cap 51 is substantially the same as the cross-sectional area of the gap formed between a remaining portion of the bottom surface of the end cam cap 80, which excludes the front end portion of the bottom surface of the end cam cap 80, and a remaining portion of the bottom surface 51a of the recess for cam cap 51, which excludes the front end portion of the bottom surface 51a.
Then, the front end portion of the bottom surface of the end cam cap 80 and the front end portion of the bottom surface 51a of the recess for cam cap 51 may hardly generate a resistance force to prevent the gasket G positioned between the bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51 from moving to the chain storage space 89 when the negative pressure in the chain storage space 89 is exerted on the gasket G. This problem occurs when the end cam cap 80 and the recess for cam cap 51 are not tightly fixed by using the bolts and each of the female screw holes 53. Then, in this case, there is a slight possibility of the gasket G being discharged to the chain storage space 89 via the gap between the front end portion of the bottom surface of the end cam cap 80 and the front end portion of the bottom surface 51a.
However, in the present embodiment, the gasket G is sandwiched between the bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51 with a strong force by using the bolts and each of the female screw holes 53. Therefore, the gasket G is not discharged to the chain storage space 89 via the gap between the front end portion of the bottom surface of the end cam cap 80 and the front end portion of the bottom surface 51a.
Furthermore, the negative pressure in the chain storage space 89 is also exerted on the gasket G that is semi-solidified in the left and right cross-sectional area gradually changing gaps S.
However, the cross-sectional area of each of the cross-sectional area gradually changing gaps S gradually decreases as approaching from the rear end of each of the cross-sectional area gradually changing gaps S to the front end of each of the cross-sectional area gradually changing gaps S.
Then, the front end portions of the side surfaces of the end cam cap 80 and the front end portions of the side surfaces 51b of the recess for cam cap 51 generate a large resistance force to prevent the gasket G from moving to the chain storage space 89.
Therefore, the gasket G does not pass through the front end portion of each of the cross-sectional area gradually changing gaps S and is not discharged to the chain storage space 89.
The left and right side surfaces of the end cam cap 80 may be constituted by flat surfaces parallel to the left and right side surfaces 51b of the recess for cam cap 51.
In this case, however, the same problem as the above problem on the bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51, which occurs when the bolts are not threaded to each of the female screw holes 53, occurs. Namely, a chance that the semi-solidified gasket G is discharged to the chain storage space 89 via the gap between the left and right side surfaces of the end cam cap 80 and the left and right side surfaces 51b of the recess for cam cap 51 becomes larger compared with the case where the cross-sectional area gradually changing gaps S are formed between the end cam cap 80 and the recess for cam cap 51.
In contrast, in the present embodiment, since the cross-sectional area gradually changing gaps S are formed between the left and right gap forming surfaces 83 of the end cam cap 80 and the left and right side surfaces 51b of the recess for cam cap 51, such a problem does not occur.
Thus, in the internal combustion engine 10, the second lubricating oil 101 in the camshaft storage space 47a of the camshaft housing 47 and the interior space of the cylinder head cover 87 does not flow into the cylinder block 20 and the oil pan 30, and then does not leak to the chain storage space 89.
Therefore, the amount of the second lubricating oil 101 in the camshaft storage space 47a of the camshaft housing 47 and the interior space of the cylinder head cover 87 does not decrease.
Then, the intake valves 44, the exhaust valves 45, the exhaust camshaft 65, the intake camshaft 70, the rocker arms 84, and the HLAs 85 can always operate smoothly.
Noted that, a gap forming surface, which is constituted by an inclined surface corresponding to the gap forming surface 83, may be formed on the bottom surface of the end cam cap 80, and then a cross-sectional area gradually changing gap S having a triangular shape in a side view may be formed between the bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51. In this case, this cross-sectional area gradually changing gap S is filled with the gasket G.
However, in this case the bottom surface 51a of the recess for cam cap 51 supports the end cam cap 80 unstably.
On the other hand, in the present embodiment, since the bottom surface of the end cam cap 80, which is a horizontal flat surface, is supported by the bottom surface 51a of the recess for cam cap 51, which is a horizontal flat surface, such a problem does not occur.
Furthermore, in the internal combustion engine 10, the end cam cap 80 is disposed in the recess for cam cap 51 formed in the chain cover adjacent wall 48 of the camshaft housing 47. In other words, the cover adjacent wall 48 and the end cam cap 80 are disposed at the same position in the forward and rearward direction.
Therefore, compared with a conventional internal combustion engines, the present invention can reduce the forward and rearward direction dimensions of the camshaft housing 47 and the entire internal combustion engine 10.
Although, the present invention has been described based on the above embodiment. However, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the object of the present invention.
For example,
In the first modified embodiment shown in
In the second modified embodiment shown in
In the third modified embodiment shown in
In each of the modified embodiments shown in
Furthermore, the cross-sectional area of the cross-sectional area gradually changing gap S1 of the first modified embodiment, which is formed by cutting this cross-sectional area gradually changing gap S1 with a plane orthogonal to the forward and rearward direction, is gradually reduced as approaching from the rear thereof to the front thereof (i.e., the front surface of the end cam cap 80). In addition, the cross-sectional area of the cross-sectional area gradually changing gap S2 of the second modified embodiment, which is formed by cutting this cross-sectional area gradually changing gap S2 with a plane orthogonal to the forward and rearward direction, is gradually reduced as approaching from the front end of the flat surface 121a to the front thereof. Furthermore, the cross-sectional area of the cross-sectional area gradually changing gap S3 of the third modified embodiment, which is formed by cutting this cross-sectional area gradually changing gap S3 with a plane orthogonal to the forward and rearward direction, is gradually reduced as approaching from the front end of the flat surface 122b to the front thereof.
Therefore, each of these modified embodiments can produce the same effect as that of the above embodiment.
In the fourth modified embodiment shown in
In this modified embodiment, each of the cross-sectional area gradually changing gaps S4 formed between the gap forming surfaces 123 and the side surfaces 51b are filled with the gasket G, respectively. Furthermore, a gap between the bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51 is filled with the gasket G. In this modified embodiment as well, the gaskets G, which are between the left and right side surfaces of the end cam cap 80 and the left and right side surfaces 51b of the recess for cam cap 51, and the gasket G, which is between the bottom surface of the end cam cap 80 and the bottom surface 51a of the recess for cam cap 51, are continuous with each other.
The gasket G filled in the front portion of each of the cross-sectional area gradually changing gaps S4 receives the negative pressure from the chain storage space 89.
However, in this modified embodiment, the front portion of each of left and right side surfaces of the end cam cap 80 and the front portion of each of side surfaces 51b faces with each other so as to form a minute gap and be parallel to each other. No gasket G is filled in a gap between the front portion of each of the left and right side surfaces of the end cam cap 80 and the front portion of each of side surfaces 51b.
Then, the gasket G filled in the front portion of each of the cross-sectional area gradually changing gaps S4 hardly move to the gap between the front portion of each of left and right side surfaces of the end cam cap 80 and the front portion of each of the side surfaces 51b. Namely, there is an extremely small possibility that the gasket G is discharged to the chain storage space 89 after passing through the gap between the front portion of each of the left and right side surfaces of the end cam cap 80 and the front portion of each of side surfaces 51b. Therefore, a chance that the second lubricating oil 101 in the interior spaces of the camshaft storage space 47a and the cylinder head cover 87 leaks to the chain storage space 89 after passing through the gaps between the side surfaces of the end cam cap 80 and the side surfaces 51b of the recess for cam cap 51 is much smaller compared with the case where the front end portion of each of the cross-sectional area gradually changing gaps S4 is positioned at the same position as the front surface of the end cam cap 80.
Both side surfaces of each of the end cam caps 80 may be constituted by flat surfaces that are parallel to each other and the both side portions of each recess for cam cap 51 may be cut out (notched) so that the both side surfaces of each recess for cam cap 51 and the both side surfaces of each of the end cam caps 80 form each of the cross-sectional area gradually changing gaps S, S1, S2, S3, S4 therebetween, respectively.
The internal combustion engine 10 may comprise an annular timing belt (an annular interlocking member) that interlocks the crank shaft 25, the exhaust camshaft 65, and the intake camshaft 70 each other instead of the timing chain 86.
The internal combustion engine 10 may be configured so that the intake valves 44 and the exhaust valves 45 are opened and closed by one camshaft.
The internal combustion engine 10 may be configured as the fifth modified embodiment shown in
The cover member 88 of the internal combustion engine 10 in
The cover member 88 of the internal combustion engine 10 in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-116854 | Jun 2016 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 8051820 | Shoji | Nov 2011 | B2 |
| Number | Date | Country |
|---|---|---|
| H08-246831 | Sep 1996 | JP |
| 2011-190721 | Sep 2011 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20170356315 A1 | Dec 2017 | US |
