Vehicle engine insulators

Abstract

To improve cooling performance and an antirust effect in an insulator disposed in an exhaust part of a vehicular engine.SOLUTION: An insulator 8 comprises: a first portion 21 forming a shell structure comprising the first portion 21 and wall parts 21b-21d; a second portion 22 erecting from a base end of an upper surface part 21a of the first portion 21; and a third portion 23 extended from an upper end of the second portion 22 to a cylinder head 2 side. Ventilation openings 32, 33 that are long in right and left directions are provided at the base end part of the upper surface part 21a, and upward ventilation openings 32, 33 that are long in the right and left directions are provided at portions close to the base end of the first portion 21. A fourth ventilation opening 35 that is long in the right and left directions is provided at an upper end part of the tip wall part 21d of the first portion 21. It is also possible to provide a ventilation opening 35 that is long in the right and left directions at an intermediate height position of the upper surface part 21.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a heat insulating insulator disposed on the exhaust side of a vehicle engine. [Background technology]

[0002] Exhaust gas from the engine is discharged from the exhaust manifold, which becomes very hot and is therefore often insulated from heat by a metal insulator. This insulator is designed to cover the exhaust manifold, but because the exhaust manifold faces laterally from the cylinder head and then curves downward, the insulator also has a shell structure with a top surface that covers the exhaust manifold from above and a wall that covers it from the side (outer periphery), as disclosed in Patent Documents 1 and 2.

[0003] Because the insulator covers the exhaust manifold, heat is trapped inside it. In this regard, Patent Document 1 focuses on the fact that a recess is formed on the exhaust side of the cylinder head, and discloses that the upper end of the insulator is inserted into the recess of the cylinder head to form a ventilation path that takes in the wind generated during running into the insulator. Patent Document 1 also discloses that a warm air introduction pipe is connected to the insulator to take in the warm air heated by the exhaust manifold into the intake system.

[0004] On the other hand, in Patent Document 2, the flange of the insulator overlaps with the exhaust side surface of the cylinder head in a plan view (as viewed in the axial direction of the cylinder bore), which suggests that the flange plate of the exhaust manifold and the flange of the insulator form the same surface. In Patent Document 2, a ventilation opening is provided on the top surface of the insulator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-319886 [Patent Document 2] JP 2002-235554 A Summary of the Invention [Problem to be solved by the invention]

[0006] As in Patent Document 1, fitting the upper end of the insulator into the recess in the cylinder head not only prevents rainwater that has entered the engine compartment from coming into contact with the exhaust manifold, but also has the advantage of cooling the insulator from the inside and improving its durability. However, after the engine leaves the cold start state, hot air generated inside the insulator is discharged through the warm air intake pipe, which raises concerns that the hot air may not be completely discharged.

[0007] On the other hand, in Patent Document 2, it is assumed that the flange portion of the insulator and the flange plate of the exhaust manifold are flush with each other. Therefore, if there is a recess on the exhaust manifold mounting surface as disclosed in Patent Document 1, there is a concern that hot air will rise upward from the gap between the insulator and the cylinder head and cause thermal damage to the head cover.

[0008] The present invention has been made to improve this current situation. [Means for solving the problem]

[0009] Vehicle engines are positioned such that the crankshaft is longer in the width direction of the vehicle, or longer in the front-to-rear direction of the vehicle. For horizontal engines, there are front exhaust, with the exhaust side facing the front of the vehicle, and rear exhaust, with the exhaust side facing the rear of the vehicle. The horizontal, front exhaust system has the advantage of being able to effectively use the wind generated when the engine is running to cool the engine and exhaust system components.

[0010] The present invention is based on a vehicle engine with a horizontally mounted front exhaust system, and is provided with an exhaust manifold fixed to the exhaust side of the engine (cylinder head) via a flange plate. A single structure that covers only the opposite side of the cylinder headThis relates to an insulator, which is " The exhaust manifold has an upper surface portion that mainly covers the exhaust manifold from above, a vertical surface portion that is oriented nearly vertically so as to cover the exhaust manifold from the lateral direction opposite the cylinder head, and an intermediate portion that is oriented in an inclined manner and is connected to the upper surface portion and the vertical surface portion, and the shape of the exhaust manifold smoothly changes from top to bottom from the upper surface portion to the vertical surface portion, The upper surface an inwardly extending portion is formed at an upper end thereof, the inwardly extending portion covering a flange plate of the exhaust manifold in a plan view and entering a recess in an exhaust side surface of the engine; The upper surface portion has an upward ventilation opening that opens mainly in the vertical direction, the vertical surface portion has a forward ventilation opening that opens mainly in the front-rear direction of the vehicle body, and the intermediate portion has an intermediate ventilation opening that opens both in the vertical direction and the front-rear direction. The structure is as follows.

[0012] The present invention can be developed in various ways. For example, in claim 2, "In the plan view, the spacing in the vehicle width direction becomes smaller as it goes away from the engine, and the vehicle is formed in a shell shape having a wall portion located in the vehicle width direction." The following configuration is adopted. Effect of the Invention

[0013] The insulator of the present invention, like that of Patent Document 1, has its upper end inserted into the recess of the cylinder head, which prevents hot air from rising upward and prevents thermal damage to the head cover. In addition, it also has the advantage of making it easier for the wind generated during running to enter the inside of the insulator, improving the cooling performance of the exhaust manifold and the insulator.

[0014] Furthermore, the insulator Three types Ventilation openings are formed, allowing hot air to be efficiently exhausted outside the insulator. Along with Since the function of taking in the wind generated by traveling into the inside of the insulator can be improved, the inside of the insulator can be prevented from becoming excessively hot, thereby improving the durability of the exhaust manifold and the insulator.

[0015] Furthermore, in a configuration in which hot air inside the insulator is exhausted through a warm air inlet pipe, as in Patent Document 1, there is a risk that the hot air will not escape sufficiently due to flow resistance. However, by providing a ventilation opening in the insulator, as in the present invention, it is possible to ensure that the hot air can escape, thereby ensuring improved cooling performance.

[0016] That is, as in the present invention,By providing an upward ventilation opening and a forward ventilation opening, the wind generated during driving can be taken in through the forward ventilation opening and discharged through the upward ventilation opening, thereby increasing the air permeability inside the insulator and further improving the cooling performance of the exhaust manifold and the insulator.

[0017] In addition, the wind taken in from the forward ventilation opening flows upward while being guided by the exhaust manifold, preventing the wind from entering the inside of the insulator through the recessed portion of the cylinder head. This prevents rainwater that has entered the engine compartment of the vehicle from entering the inside of the insulator, preventing the exhaust manifold from rusting due to rainwater. This improves the cooling performance of the exhaust manifold and the insulator while preventing the exhaust manifold from rusting.

[0018] Claim 2 In this case, the insulator has a shell structure that narrows in the direction away from the engine (cylinder head), so it can diffuse the wind toward the cylinder head. This allows the branch pipes that make up the exhaust manifold to be cooled efficiently. As a result, it can further contribute to improving the durability of the exhaust manifold and insulator. [Brief description of the drawings]

[0019] [Figure 1] FIG. [Diagram 2] FIG. 2 is a side perspective view of the embodiment. [Diagram 3] FIG. 2 is a partial side view of the cylinder head. [Figure 4] FIG. 4 is a side view showing the exhaust manifold attached. [Diagram 5] FIG. 2 is a side view showing an insulator and an exhaust manifold separated from each other. [Figure 6] FIG. 2 is a cross-sectional view taken along line VI-VI of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to a three-cylinder engine for an automobile. For convenience, the terms "front-rear direction" are used to refer to the forward direction and "rear direction" to the reverse direction. In other words, they are directions as seen by the driver. The same is true for the left-right direction. Since the engine is a transversely mounted front exhaust type, the crankshaft direction is the left-right direction. With regard to engines, the crankshaft direction is often referred to as the front-rear direction, but this direction is different in this embodiment.

[0021] (1) Structure Description As shown in Figures 1 and 6, the engine comprises a cylinder block 1, a cylinder head 2 fixed to its upper surface, and a head cover 3 fixed to the upper surface of the cylinder head 2. As shown in Figure 3, a land portion 4 is formed on the exhaust side of the cylinder head 2, extending left and right, and three exhaust ports 5 open into the land portion 4, lined up left and right. The surface of the land portion 4 forms a flat exhaust manifold mounting surface.

[0022] An exhaust manifold 7 is fixed to the land portion 4 via a gasket 6 (see FIG. 6) made of metal or inorganic material, and the exhaust manifold 7 is covered with a metal insulator (heat shield) 8. The width direction of the engine is the front-rear direction, and as shown in FIG. 2, in the front-rear direction (direction perpendicular to the exhaust side), the side closer to the cylinder head 2 is the base end side (inner side), and the side farther from the cylinder head 2 is the tip side (outer side).

[0023] 4 and 5, the exhaust manifold 7 has a flange plate 9 overlapping the gasket 6 and three branch pipes 10a to 10c joined thereto, and the three branch pipes 10a to 10c are gathered into one collecting pipe 11, and an upper cone portion of a catalyst case 12 is joined to the collecting pipe 11. As shown in Fig. 6, a reinforcing piece 9a protruding outward is provided on the outer periphery of the flange plate 9.

[0024] As can be seen from Fig. 6, the branch pipes 10a-10c and the collecting pipe 11 that make up the exhaust manifold 7 are each made of two half-cut plates overlapping each other to form a hollow space, and the two plates are fixed by welding at flange-shaped edge pieces 13. The upper cone of the catalyst case 12 is provided with a boss 14 for mounting an O2 sensor.

[0025] As can be seen from Figure 4, the flange plate 9 of the exhaust manifold 7 is fixed to the exhaust side of the cylinder head 2 at a total of five locations, three at the top and two at the bottom, with bolts 15. Five boss portions 16, which are flush with the surface of the land portion 4 and protrude in the vertical direction, are formed on the exhaust side of the cylinder head 2, and each boss portion 16 has a tapped hole 17 formed therein.

[0026] For example, as shown in FIG. 6 , stud bolts are used as the fastening bolts 15 of the exhaust manifold 7, and the flange plate 9 of the exhaust manifold 7 is fixed to the land portion 4 by nuts 18 screwed onto the stud bolts 15.

[0027] 4, each of the branch pipes 10a to 10c that make up the exhaust manifold 7 protrudes sideways from the cylinder head 2 and bends downward before converging into a collecting pipe 11. Also, since the collecting pipe 11 is positioned offset toward the rear of the cylinder head 2, the branch pipe (first branch pipe) 10a located at the front is long, while the branch pipe (second branch pipe) 10b located in the middle and the branch pipe (third branch pipe) 10c located at the rear are about the same length.

[0028] The exhaust manifold 7 is configured with the multiple branch pipes 10a to 10c and the collecting pipe 11, so that the exhaust manifold 7 has a shape close to a trapezoid in a plan view. For this reason, the insulator 8 also has a basic trapezoid shape similar to that of the exhaust manifold 7.

[0029] More precisely, the insulator 8 has, as its basic portion, an upper surface portion 21a that covers the exhaust manifold 7 from above, and wall portions 21b, 21c, and 21d that surround the exhaust manifold 7 in the front-rear direction and from the sides, and these together form a shell-structured first portion (main body portion) 21. Reference numeral 21b denotes the right wall portion, reference numeral 21c denotes the left wall portion, and reference numeral 21d denotes the tip wall portion located farther from the cylinder head 2. The upper surface portion 21a is nearly horizontal, while the tip wall portion 21d is nearly vertical, forming a vertical surface portion as described in the claims.

[0030] The upper surface portion 21a is continuous with the tip wall portion 21d and curves downward as it becomes farther away from the cylinder head 2. Therefore, the boundary between the upper surface portion 21a and the tip wall portion 21d is unclear, and more precisely, it can be said that the portion of the insulator 8 visible in a plan view is a curved portion that becomes lower as it becomes farther away from the cylinder head 2. In any case, the upper surface portion 21a and the tip wall portion 21d are integrally connected via the intermediate portion 21e, which changes its position downward as it moves away from the cylinder head 2.

[0031] A second portion 22 rises upward from a base end of the upper surface portion 21a that is close to the cylinder head 2, and a third portion 23 extends from the upper end of the second portion 22 toward the cylinder head 2. The third portion 23 has a substantially uniform width over its entire length.

[0032] The second portion 22 of the insulator 8 has horn-shaped upward protrusions 22a formed at both left and right ends, with a recess (valley) 22b between the left and right upward protrusions 22a. Thus, following the shape of the second portion 22, the third portion 23 also has upper step portions 23a at both left and right ends, and a lower step portion 23b between them. As shown in FIG. 2, the second portion 22 has side plates connected to the left and right walls 21b, 21c of the first portion 21 and the left and right ends of the third portion 23 at both left and right ends. 22c are integrally formed.

[0033] The insulator 8 is fixed to the exhaust manifold 7 at three locations: the left and right upward protrusions 22a provided on the second portion 22, and the tip wall portion 21d constituting the first portion 21. As can be clearly seen from Fig. 5, first, a main body side bracket 24 is fixed by welding to the upper left and right ends of the flange plate 9 of the exhaust manifold 7, the main body side bracket 24 being inclined so as to shift outward to the left and right as it goes upward.

[0034] Furthermore, a pedestal-shaped tip side bracket 25 is fixed by welding to the outer surface of the collecting pipe 11 of the exhaust manifold 7, and a stud bolt 26 is provided protruding laterally from these brackets 24, 25, and the upward protrusion 22a of the second portion 22 of the insulator 8 and the tip wall portion 21d of the first portion 21 are fixed with a nut 27 (see FIG. 1). Therefore, as shown in FIG. 5, a bolt insertion hole 28 is formed in the upward protrusion 22a of the second portion 22 of the insulator 8 and the tip wall portion 21d of the first portion 21.

[0035] 2 and 5, a pair of front and rear reinforcing ribs 29 are formed to bulge outward at a portion of the insulator 8 where the top surface 21a is connected to both the left and right ends of the second portion 22. That is, the reinforcing ribs 29 are formed to straddle both the upward protrusion 22a of the second portion 22 and the top surface 21a. A bulge 30 is also formed at the tip wall 21d, and a bolt insertion hole 28 is formed in the bulge 30. Furthermore, a rectangular bulge 31 is also provided to protrude upward at a portion of the top surface 21a constituting the first portion 21, which is closer to the second portion 22 and slightly toward the front.

[0036] Furthermore, a first ventilation opening 32 is provided on the upper surface 21a constituting the first portion 21 in a portion close to the second portion 22 and toward the right, and a second ventilation opening 33 is provided on the upper surface 21a in a portion close to the second portion 22 and toward the left, Of the intermediate portion 21e A third ventilation opening 34 is provided in the right-hand portion. A fourth ventilation opening 35 is provided in the right-hand portion of the tip wall 21d in a portion above the bulging portion 30.

[0037] In relation to the claims, the first and second ventilation openings 32 and 33 correspond to upward ventilation openings, and the fourth ventilation opening 35 corresponds to a forward ventilation opening. corresponds to an intermediate ventilation opening, It is open both upward and forward.

[0038] As shown in Fig. 6, the portion of the exhaust side of the cylinder head 2 above the land portion 4 is a recess 38 recessed inward, and its upper end is a eaves-like portion 2a that protrudes outward beyond the land portion 4. Furthermore, water jackets 36, 37 are formed above and below the group of exhaust ports 5 on either side of the land portion 4 of the cylinder head 2, and the water jackets 36, 37 extend to the surface side in the areas between adjacent exhaust ports 5. Due to this relationship, the recess 38 of the cylinder head 2 is formed with a deep portion 38a that extends further into the interior of the cylinder head 2.

[0039] On the other hand, the base end of the third portion 23 of the insulator 8 is disposed so as to cover the flange plate 9 of the exhaust manifold 7 from above, and a gap 39 that allows ventilation is provided between the base end of the third portion 23 and the cylinder head 2. Therefore, the third portion 23 of the insulator 8 serves as an inward entry portion as recited in the claims.

[0040] (2) Summary In this embodiment, the exhaust manifold 7 is entirely covered from the front with the insulator 8, so that the harness and the like can be prevented from being damaged by the heat of the exhaust manifold 7. This improves the safety of people even during inspections while the engine is running. Furthermore, there is an advantage that the heat radiation is suppressed, so that the catalyst can be heated quickly, particularly during cold engine operation. In addition, the insulator 8 is curved in a side view and formed in a shell shape having the walls 21b to 21d, so that it has very high rigidity overall.

[0041] In this embodiment, as shown in FIG. 6, the flange plate 9 of the exhaust manifold 7 is disposed in the third portion of the insulator 8. 23The third part is covered with 23 Since the insulator 8 enters the recess 38 of the cylinder head 2, hot air generated inside the insulator 8 is prevented from rising toward the head cover 3. This makes it possible to prevent the head cover 3 from being damaged by heat.

[0042] In this embodiment, the traveling wind is also taken in through the fourth ventilation opening 35, part of which diffuses upward while cooling the first portion 21, and part of which escapes upward through the first and second ventilation openings 32 and 33. This increases the ventilation inside the insulator 8, thereby improving the cooling performance of the exhaust manifold 7 and the insulator 8. Although the gap 39 above the land portion 4 allows ventilation, a portion of the traveling wind that enters the inside of the insulator 8 from the fourth ventilation opening 35 is guided by the exhaust manifold 7 and flows upward, so that the traveling wind does not enter the inside of the insulator 8 from the gap 39, and it is possible to prevent moisture from entering the inside of the insulator 8. Therefore, rusting of the exhaust manifold 7 can be prevented and durability can be improved.

[0043] Furthermore, a portion of the traveling wind that flows into the inside of the insulator 8 from the fourth ventilation opening 35 is guided by the exhaust manifold 7 and flows upward, but because the insulator 8 widens in width toward the cylinder head 2, the air rises while diffusing in the left-right direction, and exits the insulator 8 from the first and second ventilation openings 32, 33 (and the third ventilation opening 34). In this respect as well, ventilation inside the insulator 8 is improved, and the cooling of the exhaust manifold 7 and the insulator 8 can be improved.

[0044] Now, when looking at the heat distribution in the exhaust manifold 7, it can be said that the intermediate portions of the first branch pipes 10a-10c and the terminal portions of the second and third branch pipes 10a-10c reach the highest temperatures due to the straightness of the exhaust gas, but as can be easily understood from Fig. 5, the first to third ventilation openings 32-34 are located above the parts of the exhaust manifold 7 that reach the highest temperatures, so that the wind from traveling escapes through the first to third ventilation openings 32-34, thereby accurately cooling the parts of the exhaust manifold 7 that reach the highest temperatures. This is one of the features of this embodiment.

[0045] Although the embodiment of the present invention has been described above, the present invention can be embodied in various other ways. For example, the exhaust manifold can be embodied in various forms depending on the number of cylinders, the position of the collecting pipe, etc., and accordingly, the insulator can be embodied in various forms.

[0046] In the case of an insulator for a four-cylinder engine, four ventilation openings should be provided corresponding to the four branch pipes, and in the case of an insulator for a six-cylinder engine, six ventilation openings should be provided corresponding to the six branch pipes. That is, a ventilation opening should be provided above the hottest part (the bend where the exhaust gas that has traveled straight collides) for each branch pipe. [Industrial Applicability]

[0047] The present invention can be embodied in an insulator for a vehicle engine, and is therefore industrially applicable. [Explanation of symbols]

[0048] 2. Cylinder head 4 Land section (exhaust manifold mounting surface) 5 Exhaust port 7 Exhaust manifold 8 Insulator 10a~10c branch pipe 11 Collecting pipe 21 1st part (main body) 21a Upper surface (curved portion) 21b to 21d: Wall of the first portion 22 Part 2 23 The third section, which is the inward approach section 29 Reinforcing rib 32,33 Upward ventilation opening (1st and 2nd ventilation opening) 34 intermediate to the point Wind opening (third ventilation opening) 35 Forward-facing ventilation opening (4th ventilation opening) 38 Cylinder head recess 39 Ventilation duct

Claims

1. A single-structure insulator that covers an exhaust manifold fixed via a flange plate to a transversely mounted front exhaust type vehicle engine only from the side opposite to a cylinder head, The exhaust manifold has an upper surface portion that mainly covers the exhaust manifold from above, a vertical surface portion that is oriented nearly vertically so as to cover the exhaust manifold from the lateral direction opposite the cylinder head, and an intermediate portion that is oriented in an inclined manner and is connected to the upper surface portion and the vertical surface portion, and the shape of the exhaust manifold smoothly changes from top to bottom from the upper surface portion to the vertical surface portion, an inwardly extending portion is formed at an upper end of the upper surface portion, the inwardly extending portion covering a flange plate of the exhaust manifold in a plan view and entering a recess in an exhaust side surface of the engine; The upper surface portion has an upward ventilation opening that opens mainly in the vertical direction, the vertical surface portion has a forward ventilation opening that opens mainly in the front-rear direction of the vehicle body, and the intermediate portion has an intermediate ventilation opening that opens both in the vertical direction and the front-rear direction. Vehicle engine insulator.

2. The space in the vehicle width direction becomes smaller as the distance from the engine increases in the plan view, and the space is formed in a shell shape having a wall portion located in the vehicle width direction.

2. An insulator for a vehicle engine according to claim 1.

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