JP2004052546A - Multi-cylinder engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize the whole body of an engine by effectively using a dead space between a lower surface of an overhung part and a side surface of a cylinder block in the multi-cylinder engine equipped with the overhung part for forming a collection exhaust pipe at the cylinder block. <P>SOLUTION: The overhung part 49 projecting more outward than the side surface of a cylinder block 11 is provided in a cylinder head 12. In the overhung part 49, the collection exhaust port 18 for integrally collecting exhaust ports 46 extending from a plurality of combustion chambers 16 at an exhaust collection part 47 is formed. An exhaust gas purifying catalyst 41 connecting to the collection exhaust port 18 is arranged along the side face of the cylinder head 11, and at least a part of the exhaust gas purifying catalyst 41 is overlapped with the lower part of the overhung part 49 viewed from the cylinder axis line L<SB>1</SB>so that the whole body of the engine is miniaturized by using the dead space between the lower surface of the overhung part 49 and the side face of the cylinder block 11. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multi-cylinder engine including a collective exhaust port provided at a projecting portion of a cylinder head and an exhaust gas purifying catalyst connected to the exhaust port.
[0002]
[Prior art]
Generally, an exhaust port formed in a cylinder head of a multi-cylinder engine collects only exhaust gas discharged from a plurality of exhaust valve holes of the same cylinder inside the cylinder head, and collects exhaust gas discharged from each cylinder. Is performed in a separate exhaust manifold connected to the cylinder head.
[0003]
On the other hand, Japanese Patent Publication No. 2709815 discloses a method in which exhaust gas discharged from each cylinder is collected inside a cylinder head without using a separate exhaust manifold. In order to ensure durability even when using a material with poor heat resistance, this cylinder head is surrounded by a water jacket around the entire circumference of the collective exhaust port that is integrated inside the cylinder head to increase cooling efficiency. It has become.
[0004]
[Problems to be solved by the invention]
By the way, as disclosed in the above-mentioned Japanese Patent No. 2709815, in a case where a side surface of a cylinder head is provided with a projecting portion projecting outward beyond a side surface of a cylinder block to which the cylinder head is coupled, Since a dead space is formed between the lower surface and the side surface of the cylinder block, it is difficult to reduce the size of the entire engine unless the dead space is effectively used.
[0005]
The present invention has been made in view of the above circumstances, and in a multi-cylinder engine provided with an overhang portion for forming a collective exhaust port in a cylinder head, in a multi-cylinder engine, a space between a lower surface of the overhang portion and a side surface of a cylinder block is provided. An object of the present invention is to reduce the size of the entire engine by effectively utilizing dead space.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a protrusion is provided on a side surface of a cylinder head so as to protrude outward from a side surface of a cylinder block to which the cylinder head is coupled. In a multi-cylinder engine in which a collective exhaust port formed by integrally collecting exhaust ports extending from a plurality of combustion chambers arranged along the exhaust collecting portion is formed in the overhang portion, exhaust gas purification connected to the collective exhaust port is provided. A multi-cylinder engine is proposed in which a catalyst is arranged along a side surface of a cylinder block and at least a part of an exhaust gas purifying catalyst overlaps the overhang when viewed in the cylinder axis direction.
[0007]
According to the above configuration, at least a part of the exhaust gas purifying catalyst arranged along the side surface of the cylinder block so as to be connected to the collective exhaust port formed in the projecting portion of the cylinder head projects in the cylinder axis direction. Since it overlaps with the portion, the dead space between the lower surface of the overhang portion and the side surface of the cylinder block is used for disposing the exhaust gas purifying catalyst, so that the entire engine can be downsized. Further, since the distance between the collective exhaust port and the exhaust gas purifying catalyst is shortened, high-temperature exhaust gas can be supplied to the exhaust gas purifying catalyst to quickly activate the exhaust gas purifying catalyst.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0009]
1 to 6 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of an engine, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is line 3-3 of FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 2, FIG. 5 is a cross-sectional view taken along arrow 5 in FIG. 2, and FIG. 6 is a cross-sectional view taken along line 6-6 in FIG.
[0010]
As shown in FIGS. 1 and 3, the in-line three-cylinder engine E includes a cylinder head 12 coupled to an upper surface of a cylinder block 11, and a head cover 13 is coupled to the upper surface of the cylinder head 12. Pistons 15 are slidably fitted inside the three cylinders 14 formed in the cylinder block 11, and combustion chambers 16 are formed on the lower surface of the cylinder head 12 facing the upper surface of the pistons 15. Is done. An intake port 17 connected to the combustion chambers 16 is opened on the intake side of the cylinder head 12, and a collective exhaust port 18 connected to the combustion chamber 16 is opened on the exhaust side of the cylinder head 12. Is connected to the exhaust pipe 19. An ignition plug insertion cylinder 21 for attaching and detaching the ignition plugs 20 is integrally formed with the cylinder head 12. Spark plug insertion tube 21 ... are inclined to the upper end collecting exhaust port 18 side with respect to the cylinder axis L _1, the thigh and the spark plug 20 is mounted to face the combustion chamber 16 at its lower end, to the upper end The ignition coil 22 is mounted.
[0011]
A valve chamber 23 formed above the cylinder head 12 and covered by the head cover 13 includes a camshaft 26 having an intake cam 24 and an exhaust cam 25, an intake rocker arm 27 and an exhaust rocker arm 28. A rocker arm shaft 29 is provided for swingably supporting.
[0012]
The valve stems 32, 32 of the intake valves 31, 31, which open and close the two intake valve holes 30, 30 facing each combustion chamber 16, project into the valve operating chamber 23, and a valve spring mounted on the projection is provided. At 33, 33, the intake valves 31, 31 are urged in the valve closing direction. A roller 34 is provided at one end of each intake rocker arm 27 to contact the intake cam 24, and the other end contacts the upper ends of the valve stems 32, 32 of the intake valves 31, 31. The valve stems 37, 37 of the exhaust valves 36, 36 for opening and closing the two exhaust valve holes 35, 35 facing each combustion chamber 16, protrude into the valve operating chamber 23, and are mounted on the protruding portions. The exhaust valves 36, 36 are urged in the valve closing direction by the springs 38, 38. One end of each exhaust rocker arm 28 is provided with a roller 39 that contacts the exhaust cam 25, and the other end contacts the upper ends of the valve stems 37 of the exhaust valves 36.
[0013]
Each intake port 17 is provided with an injector 40 that injects fuel in a direction toward the intake valve holes 30.
[0014]
As shown in FIGS. 2 and 3, three intake ports 17 extending from the three combustion chambers 16 are each formed in a Y-shape, and the three intake ports 17 are mutually assembled. It opens independently on the side surface on the intake side of the cylinder head 12 without any modification. On the other hand, the collective exhaust port 18 is composed of a total of six exhaust ports 46 extending from the three combustion chambers 16 and an arc-shaped exhaust collecting part 47 in which the six exhaust ports 46 collectively. An exhaust outlet 48 to which the exhaust pipe 19 is coupled is formed at the center of the exhaust collecting part 47.
[0015]
Side wall 12 ₁ of the exhaust side of the cylinder head 12 of the exhaust collecting portion 47 faces are flared outward curved in an arch shape, Zhang projecting from the side wall 11 ₁ of the cylinder block 11 by a distance d (see FIG. 1) The outlet 49 is formed. Therefore, exhaust collector 47 formed inside a collecting exhaust port 18 of the projecting portion 49 faces directly without going through the water jacket on the side wall 12 ₁ of the protrusion 49 which is curved in an arch shape.
[0016]
Thus, since the exhaust collecting portion 47 formed inside the collecting exhaust port 18 of the overhang portion 49 faces directly without going through the water jacket on the side wall 12 ₁ of the overhung portion 49, exhaust collector 47 and it can be made compact cylinder head 12 as compared with the water jacket is interposed between the side wall 12 _1. Moreover, since the side wall 12 ₁ is formed in an arch shape, not only allows more compact width of longitudinal end portions of the cylinder head 12 is reduced, contributing to the improved rigidity of the cylinder head 12 can do.
[0017]
As is clear from FIGS. 2 and 4, four bolt holes 50 are formed in the cylinder head 12 on the intake side and the exhaust side, respectively, and are inserted into these eight bolt holes 50 from above. The cylinder head 12 is fastened to the cylinder block 11 by screwing the _eight cylinder head fastening bolts 51 _{1 to} 518 into bolt holes 52 formed in the cylinder block 11.
[0018]
Inside the collective exhaust port 18, two wall portions 53, 54 extend so as to partition between the center cylinder 14 and the cylinders 14, 14 on both sides, and these two wall portions 53, 54 are formed. the two cylinder head fastening bolts ₅₁ 2, 51 ₃ penetrates respectively. The distal end side of the two wall portions 53 and 54, i.e., the two cylinder head fastening bolts ₅₁ 2, 51 exhaust collector 47 side than the _third, the oil return passage ₅₅ 1, respectively, 55 ₂ passes.
[0019]
The two walls 53, 54 are curved along the direction of the exhaust gas flowing in the collective exhaust port 18, i.e., pointing towards the centrally located exhaust outlet 48, and thus the two oils. return passage ₅₅ 1, 55 ₂ are offset to the exhaust outlet 48 side with respect to the two cylinder head fastening bolts ₅₁ 2, 51 ₃ adjacent thereto. The above arrangement of the oil return passage 55 _1, 55 ₂ and the cylinder head fastening bolts 51 _2, 51 _3, while avoiding an increase in size of the cylinder head 12, so as to exhaust the inside of the collecting exhaust port 18 flows smoothly Exhaust resistance can be reduced.
[0020]
Also, at the exhaust outlet 48 of the cylinder head 12, three boss portions 58 ₁ , 58 ₂ , 58 ₃ into which three bolts 57... For coupling the mounting flange 56 of the exhaust pipe 19 are screwed are formed. with respect to the cylinder row _{L 2} direction to the two boss portions ₅₈ 1 away, 58 _2, 1 two oil return passages _55, 55 ₂ are offset by a distance α respective cylinder bank _{L 2} direction. Thus, the wall portion 53 and the boss portion 58 ₁ is brought close to one another, and while increasing the rigidity in the vicinity of the exhaust outlet 48 of the cylinder head 12 to each other to approximate the wall portion 54 and the boss portion 58 _2, the exhaust An increase in exhaust resistance can be prevented by preventing the flow path cross-sectional area of the collecting portion 47 from becoming small.
[0021]
Since the number of the exhaust pipes 19 is one, the two boss portions 58 ₁ and 58 ₂ on the lower side as viewed from above are not hidden under the exhaust pipe 19, and the two boss portions 58 are not hidden. _1, 58 ₂ fastening operation of the bolt 57 relative to can be performed easily. In addition, by providing the one boss portion 58 ₃ to the upper side of the exhaust pipe 19, it is possible to exhaust pipe 19 while securing the bolts 57 ... fastening operation of the fixed and in three places increasing the mounting rigidity.
[0022]
As is clear from FIG. 1, the exhaust pipe 19 connected to the exhaust outlet 48 of the collective exhaust port 18 formed in the overhang portion 49 of the cylinder head 12 is bent downward by 90 °, and has a substantially cylindrical shape. Exhaust gas purifying catalyst 41 is provided. A part of the exhaust gas purifying catalyst 41 arranged vertically along the side surface of the cylinder block 11 enters under the overhang 49 of the cylinder head 12. That is, when viewed in the direction of the cylinder axis L <b> ₁ , a part of the exhaust gas purification catalyst 41 overlaps below the protrusion 49 of the cylinder head 12.
[0023]
Thus, at least a portion of the exhaust gas purifying catalyst 41, and the lower surface of the projecting portion 49 of the cylinder head 12, the recess 43 formed with the side surface of the cylinder block 11 by the upper surface of the crankcase bulge portion 11 ₂ (See FIG. 1), the entire engine E including the exhaust gas purifying catalyst 41 can be made compact. Moreover, since the exhaust gas purifying catalyst 41 is disposed at a position very close to the exhaust outlet 48 of the collective exhaust port 18, the high-temperature exhaust gas is supplied to the exhaust gas purifying catalyst 41 to quickly raise the temperature and promote its activation. can do.
[0024]
A cam drive chain chamber 59 for accommodating a cam drive chain (not shown) is formed at one longitudinal end of the cylinder head 12, and a cylinder head fastening bolt located on the opposite side of the cam drive chain chamber 59. the third oil return passage 55 ₃ is formed in the vicinity of 51 _4. These three oil return passages 55 ₁ , 55 ₂ , 55 ₃ connect the valve operating chamber 23 provided in the cylinder head 12 to an oil pan (not shown) via an oil return passage 60 provided in the cylinder block 11. To communicate with
[0025]
Thus, the two oil return passages 55 _1, 55 _2, so was placed surrounded by adjacent cylinders 14 an exhaust port 46 and the exhaust collecting portion 47 of the region, interfere with the collecting exhaust port 18 no oil return becomes possible to form a passage 55 _1, 55 ₂ on the exhaust side of the cylinder head 12, the oil in the valve operating chamber 23 of the cylinder head 12 can be reliably returned to the oil pan. Moreover it is possible to heat the oil return passage 55 _1, 55 ₂ through the oil at a low temperature in the exhaust gas passing through the collecting exhaust port 18, the lubrication was warmed oil without providing a special oil heater Frictional resistance can be reduced.
[0026]
As is clear from FIGS. 5 and 6, the three spark plug insertion cylinders 21 arranged at an inclination on the exhaust side of the cylinder head 12 and the upper surface of the overhang portion 49 have reinforcing walls 61 having a triangular cross section. Respectively. The rigidity of the overhang portion 49 is increased by the reinforcing walls 61, and the vibration of the overhang portion 49 during operation of the engine E can be effectively suppressed.
[0027]
As shown in FIGS. 1 to 4, a water jacket J < _b > ₁ is formed inside the cylinder head 12 so as to be along the cylinder row L < _b > ₂ . Water jackets J ₂ and J ₃ that cover the upper and lower surfaces of the collective exhaust port 18, respectively, are provided on the projecting portion 49 of the cylinder head 12 that is heated by the exhaust gas passing through the collective exhaust port 18. The upper and lower water jackets J ₂ , J ₃ communicate with each other through three water jackets J ₄ near the portion that does not interfere with the exhaust ports 46, that is, near the three ignition plug insertion cylinders 21.
[0028]
In this way, by covering the periphery of the collective exhaust port 18 with the water jackets J ₁ , J ₂ , J ₃ , J ₄ , etc., it is possible to efficiently cool the exhaust side of the cylinder head 12, which tends to have a high temperature. In particular, since the intervening water jacket J ₂ is between the ignition coil 22 ... and collecting exhaust port 18 as a weak auxiliary to heat can be effectively suppressed heat transfer to the ignition coil 22 ... (Fig. 6).
[0029]
As is apparent from FIGS. 3 and 6, the outer portion of the collecting exhaust port 18, since the directly opposite side walls 12 ₁ of the protrusion 49 without passing through the water jacket, water jacket during casting of the cylinder head 12 The structure of the core for forming J ₂ , J ₃ , J ₄ ... And the collective exhaust port 18 can be simplified.
[0030]
Because, first, a core for forming the water jackets J ₂ , J ₃ , J _4, ... Is inserted into the mold in the direction of arrow A, and then a core for forming the collective exhaust port 18 is placed in the mold. Is inserted in the direction of arrow A, but at this time, since an opening 62 exists between the upper and lower water jackets J ₂ and J ₃ , a core for forming the collective exhaust port 18 is inserted through the opening 62. Can be. Although the upper and lower water jacket J _2, J ₃ are connected to each other in three of the water jacket J 4 _..., cores corresponding to the three water jacket J 4 _... is the collecting exhaust port 18 Since the portions corresponding to the six exhaust ports 46 of the core to be formed are alternately engaged with each other, interference between both cores is avoided (see FIG. 2).
[0031]
As described above, the core for forming the water jackets J ₂ , J ₃ , J ₄ , or the core for forming the collective exhaust port 18 can be assembled to the mold without dividing the cylinder. Cost can be reduced when casting the head 12.
[0032]
Next, a second embodiment of the present invention will be described with reference to FIG.
[0033]
In the second embodiment, the split surface of the exhaust outlet 48 of the collective exhaust port 18 formed in the projecting portion 49 of the cylinder head 12 is inclined obliquely downward by 45 °. The mounting flange 56 is also inclined at approximately 45 ° with respect to the axis of the exhaust gas purifying catalyst 41. And also in this embodiment, a portion of the exhaust gas purifying catalyst 41 when viewed in the cylinder axis L ₁ direction is overlapped below the projecting portion 49, Therefore, the exhaust gas of the dead space below the overhang portion 49 The whole of the engine E can be reduced in size by utilizing the arrangement of the purification catalyst 41.
[0034]
In particular, since the exhaust outlet 48 is bent 45 ° obliquely downward, even if the amount of bending of the exhaust pipe 19 is reduced by that amount, the exhaust gas purifying catalyst 41 can be easily arranged below the overhang portion 49, The exhaust gas purification catalyst 41 can be brought closer to the cylinder block 11 to contribute to downsizing of the engine E. In addition, since the amount of bending is reduced, not only the forming of the exhaust pipe 19 is facilitated, but also the exhaust resistance can be reduced.
[0035]
Next, a third embodiment of the present invention will be described with reference to FIGS.
[0036]
In the third embodiment, the exhaust outlet 48 of the collective exhaust port 18 formed in the overhang portion 49 of the cylinder head 12 is bent 90 ° and opened downward, and the exhaust pipe 19 is substantially It is formed in a straight line. In the third embodiment, not only the operation and effect of the second embodiment can be achieved, but also the split surface of the mounting flange 42 of the exhaust outlet 48 to which the mounting flange 56 of the exhaust pipe 19 is connected is connected to the cylinder block 11. Since it is arranged on the same plane as the split surface of the cylinder head 12 to be formed, both split surfaces can be machined at the same time, and the number of processing steps can be reduced. Moreover, the three bolts 57 connecting the mounting flange 56 of the exhaust pipe 19 and the mounting flange 42 of the exhaust outlet 48 can be attached and detached from above, so that workability is improved.
[0037]
Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.
[0038]
For example, the cross section of the exhaust gas purifying catalyst 41 is not necessarily circular, be oval or have a major axis in the direction toward the cylinder axis L _1, the non-circular cross-section bulging in the direction towards the cylinder axis L ₁ If this is the case, the dead space below the overhang 49 can be used more effectively. Further, in the embodiment, the in-line three-cylinder engine E is illustrated, but the present invention can be applied to each bank of another in-line engine or a V-type engine having a different number of cylinders. In particular, the present invention can be applied to an in-line six-cylinder engine or a V-type six-cylinder engine without the influence of exhaust interference as in the in-line three-cylinder engine.
[0039]
【The invention's effect】
As described above, according to the first aspect of the present invention, at least a part of the exhaust gas purifying catalyst arranged along the side surface of the cylinder block so as to be connected to the collective exhaust port formed in the overhanging portion of the cylinder head. When viewed in the cylinder axis direction, overlaps with the overhang, so the dead space between the underside of the overhang and the side of the cylinder block is used for arranging the exhaust gas purification catalyst to reduce the overall engine size. can do. Further, since the distance between the collective exhaust port and the exhaust gas purifying catalyst is shortened, high-temperature exhaust gas can be supplied to the exhaust gas purifying catalyst to quickly activate the exhaust gas purifying catalyst.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an engine. FIG. 2 is a sectional view taken along line 2-2 of FIG. 1. FIG. 3 is a sectional view taken along line 3-3 of FIG. 2. FIG. 5 is a view in the direction of arrow 5 in FIG. 2 FIG. 6 is a sectional view taken along line 6-6 in FIG. 5 FIG. 7 is a longitudinal sectional view of an engine according to a second embodiment of the present invention FIG. FIG. 9 is a longitudinal sectional view of the engine according to the embodiment. FIG. 9 is a sectional view taken along line 9-9 of FIG.
11 Cylinder Block 12 Cylinder Head 16 Combustion Chamber 18 Collective Exhaust Port 41 Exhaust Gas Purification Catalyst 46 Exhaust Port 47 Exhaust Collecting Portion 49 Overhang L ₁ Cylinder Axis L ₂ Cylinder Row

Claims (1)

Projecting portion that projects outside the side surface of the cylinder block to which the cylinder head (12) is coupled to a side surface of the cylinder head (12) (11) (49) is provided, arranged along the row of cylinders (L ₂₎ A multi-cylinder engine in which a collective exhaust port (18) formed by integrally combining exhaust ports (46) extending from a plurality of combustion chambers (16) formed by an exhaust collecting section (47) is formed in the overhang portion (49). At
An exhaust gas purifying catalyst (41) connected to the collective exhaust port (18) is arranged along the side surface of the cylinder block (11), and at least the exhaust gas purifying catalyst (41) as viewed in the cylinder axis (L ₁ ) direction. A multi-cylinder engine characterized in that a part thereof overlaps the overhang portion (49).

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