JP4648372B2 - Cover for exhaust system of internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust device cover that covers exhaust devices such as an exhaust manifold, a supercharger, and a catalytic converter in an internal combustion engine.

  In the engine room of an automobile, an exhaust device such as an exhaust manifold, a turbocharger turbine section, and a catalytic converter is provided adjacent to the engine. Therefore, in order to prevent the operator from touching the exhaust system directly and to avoid heat damage to peripheral parts of the exhaust system such as the insulator of the engine hood, the exhaust system cover covers the upper side of the exhaust system. Is provided.

Further, an exhaust sensor for detecting the exhaust state of the internal combustion engine, that is, the air-fuel ratio and temperature of the exhaust gas, is provided at an appropriate position of the exhaust device, for example, an exhaust passage member connecting the exhaust manifold and the catalytic converter. Is equipped with a rubber insulator that is sensitive to high temperatures on the base side from which the lead wire is pulled out, so an exhaust sensor protection structure is known in which a protective cover is provided around the exhaust sensor to prevent thermal damage. (See Patent Document 1).
JP 2006-207403 A

  However, if the exhaust sensor can be attached / detached without removing the exhaust device cover, and the exhaust device cover can be attached / detached without removing the exhaust sensor, the maintainability can be improved. In the configuration in which the protective cover is fixed together with the exhaust sensor as in the protective structure, there is a difficulty in maintainability, and a configuration that can suppress heat damage to the exhaust sensor while ensuring good maintainability is desired. It is.

  The exhaust device cover also has a function to prevent foreign matter, particularly oil, from adhering to the exhaust device such as an exhaust manifold. However, a sensor hole through which the exhaust sensor is inserted is opened in the exhaust device cover. In the configuration, in order to improve maintainability, if the sensor hole is formed large and the exhaust sensor is loosely inserted with a sufficient margin, there is a disadvantage that oil easily enters from the sensor hole. It is desirable to provide a structure that prevents the intrusion of water.

  The present invention has been devised to solve such problems of the prior art, and its main purpose is to suppress heat damage to the exhaust sensor while ensuring good maintainability. An object of the present invention is to provide a cover for an exhaust device of an internal combustion engine configured to be able to do so. Another object of the present invention is to prevent oil from entering from a sensor hole through which an exhaust sensor is inserted.

In order to solve such a problem, according to the present invention, in an exhaust device cover (exhaust cover 7) disposed so as to cover an exhaust device (catalytic converter 4) of an internal combustion engine, as shown in claim 1. In order to detect the exhaust state of the internal combustion engine, a sensor hole (42) into which an exhaust sensor (28) attached to the exhaust device is loosely inserted is opened, and an opening edge of the exhaust sensor In order to protect the base portion (35) from high heat, an inner surface side protruding portion (45, 65, 81) protruding inward is provided , and this inner surface side protruding portion has a U-shaped cross-sectional shape with the upper side opened. In addition, by covering the lower side and the side of the exhaust sensor, high temperature air rising from the lower exhaust device side is prevented from directly contacting the base of the exhaust sensor .

  According to this, since the base portion of the sensor is protected from high heat by the inner surface side protruding portion provided at the opening edge portion of the sensor hole, heat damage to the exhaust sensor can be suppressed. In addition, since the exhaust sensor is loosely inserted into the sensor hole, it is not necessary to remove the exhaust device cover when the exhaust sensor is attached or detached, and it is not necessary to remove the exhaust sensor when the exhaust device cover is attached or removed. Can be secured.

  In the exhaust device cover of the internal combustion engine, as shown in claim 2, an outer surface side protruding portion that protrudes outward at the opening edge portion of the sensor hole to prevent entry of foreign matter into the sensor hole. It can be set as the structure provided with (55 * 62 * 85).

  According to this, it is possible to prevent foreign matters such as oil from entering the sensor hole by the outer surface side protruding portion provided at the opening edge of the sensor hole.

  In this case, since the attached oil flows downward on the outer surface of the exhaust device cover, the outer surface-side protruding portion may be provided at least on the upper side of the sensor hole. It is possible to prevent oil from flowing into the sensor hole by being blocked by the side protrusion.

  In the exhaust device cover of the internal combustion engine, as shown in claim 3, one of the inner surface side protruding portion and the outer surface side protruding portion is formed integrally with the cover body, and the other is separated from the cover body. It can be set as the structure fixed to the cover main body.

  As described above, according to the present invention, the exhaust sensor is loosely inserted into the sensor hole, and the base portion of the sensor is protected from high heat by the inner surface side protruding portion provided at the opening edge of the sensor hole. The heat damage to the exhaust sensor can be suppressed while ensuring the above. Furthermore, foreign matters such as oil can be prevented from entering the sensor hole by the outer surface side protruding portion provided at the opening edge of the sensor hole.

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

  FIG. 1 is a perspective view showing an automobile diesel engine to which the present invention is applied. In this diesel engine (internal combustion engine) 1, the exhaust discharged from the exhaust port of the cylinder head 2 sequentially flows through an exhaust manifold (not shown), the turbine section of the supercharger 3, and the catalytic converter 4, and the diesel engine 1 is led to an exhaust pipe extending rearward of the vehicle body through the lower side.

  The diesel engine 1 is provided with an engine cover 6 so as to cover the upper side of the head cover 5. Further, an exhaust cover (exhaust device cover) 7 is disposed so as to cover the exhaust manifold, the turbine section of the supercharger 3, and the upper side of the catalytic converter 4.

  FIG. 2 is a cross-sectional view of the exhaust cover 7 shown in FIG. FIG. 3 is a perspective view showing the outer surface side of the exhaust cover 7 shown in FIG. FIG. 4 is a perspective view showing the inner surface side of the exhaust cover 7 shown in FIG. FIG. 5 is a side view showing an upper end portion of the catalytic converter 4 shown in FIG.

  As shown in FIG. 3, the exhaust cover 7 includes an exhaust manifold cover portion 21 that covers the upper side of the exhaust manifold, a supercharger cover portion 22 that covers the upper side of the turbine portion of the supercharger 3, and an upper side of the catalytic converter 4. And the supercharger cover portion 22 and the catalytic converter cover portion 23 are formed in a shape bulging upward with respect to the exhaust manifold cover portion 21 having a generally flat plate shape. ing.

  As shown in FIG. 2, the catalytic converter 4 is provided with a cone portion 26 formed at the upper end so as to gradually expand the diameter toward the large-diameter catalyst housing portion 25. An exhaust sensor 28 is provided in the exhaust passage member 27 communicating with the turbine section of the supercharger 3.

  The exhaust sensor 28 is a LAF (Linear Air Fuel Ratio) sensor that detects the air-fuel ratio of exhaust gas, and includes a tip end portion 32 that covers the air-fuel ratio detection element 31 with a cover, and a housing 33 that holds the air-fuel ratio detection element 31. , And a base 35 in which a connector for connecting the lead wire 34 to a terminal of the air-fuel ratio detection element 31 and a rubber insulator are incorporated.

  As shown in FIG. 5, the exhaust passage member 27 is formed in an L-shape, and is provided with an attachment boss 38 in which an attachment hole 37 of the exhaust sensor 28 is opened. The distal end portion 32 of the exhaust sensor 28 is attached to the attachment hole. By inserting the housing 33 into the mounting boss 38 and inserting the housing 33 into the mounting boss 38, the distal end portion 32 is fixed to the exhaust passage member 27 in a state of protruding into the exhaust passage. In particular, here, as shown in FIG. 2, the exhaust sensor 28 is attached in a state where the tip end portion 32 side is inclined obliquely downward.

  A sensor hole 42 into which the exhaust sensor 28 is loosely inserted is formed in the catalytic converter cover 23 of the exhaust cover 7, and particularly here, as shown in FIG. 3, the exhaust manifold cover 21 in the catalytic converter cover 23 is provided. A sensor hole 42 is formed in the inclined surface portion 41 on the side, and the sensor hole 42 is opened obliquely upward.

  The sensor hole 42 is formed in a substantially circular shape centered on the center line of the exhaust sensor 28, ensures a sufficient gap with the outer peripheral surface of the exhaust sensor 28, and without removing the exhaust cover 7. The exhaust cover 7 can be smoothly attached and detached, and the exhaust cover 28 can be attached and detached smoothly without removing the exhaust sensor 28.

  As shown in FIG. 2, an inner surface side protruding portion 45 that protrudes inward is provided on the inner surface side of the opening edge portion of the sensor hole 42 in order to protect the base portion 35 of the exhaust sensor 28 from high heat. As shown in FIG. 4, the inner surface side protruding portion 45 includes a lower wall portion 46 having a semicircular arc section centering on the center line of the exhaust sensor 28, and side wall portions 47 and 48. It has an open U-shaped cross-sectional shape, and covers the lower side and the side of the exhaust sensor 28 so that high-temperature air rising from the lower catalytic converter 4 side directly enters the base 35 of the exhaust sensor 28. It is designed not to touch.

  The inner surface side projecting portion 45 is formed in a heat shield member 52 that is separate from the cover body 51 of the exhaust cover 7, and the heat shield member 52 has a mounting portion 53 for the cover body 51. The attachment portion 53 is fixed to the cover body 51 by being fixed to the inner surface of the cover body 51 by welding or the like. The heat shield member 52 can be obtained by bending a steel plate.

  Further, as shown in FIG. 2, an outer surface side protruding portion 55 that protrudes outward to prevent intrusion of oil (foreign matter) into the sensor hole 42 is provided on the outer surface side of the opening edge portion of the sensor hole 42. Is provided. As shown in FIG. 3, the outer surface side protruding portion 55 is formed in an annular shape surrounding the sensor hole 42, and the oil adhering to the vicinity of the sensor hole 42 flows down around the outer surface side protruding portion 55. Oil can be prevented from flowing into the sensor hole 42 opened upward.

  The outer surface side protruding portion 55 is formed integrally with the cover main body 51 of the exhaust cover 7, and specifically, by bending the plate material forming the cover main body 51 outward at the opening edge of the sensor hole 42. It is formed.

  FIG. 6 is a cross-sectional view of an essential part showing another example of the exhaust cover shown in FIG. FIG. 7 is a perspective view of an essential part of the exhaust cover shown in FIG. Here, at the opening edge of the sensor hole 61 into which the exhaust sensor 28 is loosely inserted, an outer surface side protruding portion 62 for preventing the entry of oil (foreign matter) into the sensor hole 61 is provided. The protrusion 62 is formed so as to be higher than the periphery by the stepped portion 63 having a required height, and the oil adhering to the vicinity of the sensor hole 61 flows down around the outer surface-side protrusion 62. Oil can be prevented from flowing into the inside. The outer surface side protruding portion 62 is formed by bending the opening edge portion of the sensor hole 42 in a step shape.

  Here, similarly to the above example, the heat shield member 66 provided with the inner surface side protruding portion 65 for protecting the base portion 35 of the exhaust sensor 28 from high heat is provided on the inner surface of the opening edge portion of the sensor hole 61. ing.

  FIG. 8 is a cross-sectional view of an essential part showing another example of the exhaust cover shown in FIG. In the above example, the inner side protrusions 45 and 65 for protecting the base portion 35 of the exhaust sensor 28 from high heat are formed in the heat shield members 52 and 66 that are separate from the cover body 51 of the exhaust cover 7. However, here, the inner surface side protruding portion 81 is formed integrally with the cover main body 51, specifically, formed by bending the plate material forming the cover main body 51 inward at the opening edge of the sensor hole 82. Is done.

  Further, in the above example, the outer surface side protruding portions 55 and 62 for preventing the oil (foreign matter) from entering the sensor holes 42 and 61 are formed integrally with the cover body 51. The outer surface protruding portion 85 is formed in an oil removing member 86 that is separate from the cover main body 51, and the oil removing member 86 is formed with a mounting portion 87 for the cover main body 51. The oil removing member 86 is fixed to the cover body 51 by being fixed to the outer surface of the cover body 51 by welding or the like.

  In the above example, the exhaust sensor detects the air-fuel ratio of the exhaust. However, the present invention is not limited to this, and for example, it is possible to detect the temperature.

It is a perspective view which shows the diesel engine of the motor vehicle to which this invention is applied. It is sectional drawing of the exhaust cover shown in FIG. It is a perspective view which shows the outer surface side of the exhaust cover shown in FIG. FIG. 3 is a perspective view showing an inner surface side of the exhaust cover shown in FIG. 2. It is a side view which shows the upper end part of the catalytic converter shown in FIG. It is principal part sectional drawing which shows another example of the exhaust cover shown in FIG. It is a principal part perspective view of the exhaust cover shown in FIG. It is principal part sectional drawing which shows another example of the exhaust cover shown in FIG.

Explanation of symbols

1 Diesel engine 3 Turbocharger 4 Catalytic converter 7 Exhaust cover (exhaust cover)
DESCRIPTION OF SYMBOLS 21 Exhaust manifold cover part 22 Supercharger cover part 23 Catalytic converter cover part 26 Cone part 27 Exhaust passage member 28 Exhaust sensor 35 Base 41 Inclined surface part 42 * 61 * 82 Sensor hole 45 * 65 * 81 Inner surface side protrusion part 51 Cover main body 52 Heat-shielding member 55, 62, 85 Projection part 66 on outer surface side Heat-shielding member 86 Oil-removing member

Claims (3)

An exhaust device cover disposed to cover an exhaust device of an internal combustion engine,
In order to detect the exhaust state of the internal combustion engine, a sensor hole in which an exhaust sensor attached to the exhaust device is loosely inserted is opened,
The opening edge of the sensor hole is provided with an inner surface side protruding portion that protrudes inward to protect the base of the exhaust sensor from high heat ,
The inner surface side protruding portion has a U-shaped cross-sectional shape with the upper side open, and covers the lower side and the side of the exhaust sensor, so that high-temperature air rising from the lower exhaust device side is covered. An exhaust device cover for an internal combustion engine, wherein the exhaust sensor is not in direct contact with the base of the exhaust sensor .   2. The internal combustion engine according to claim 1, wherein an outer surface side protruding portion that protrudes outward is provided at an opening edge portion of the sensor hole in order to prevent foreign matter from entering the sensor hole. Cover for exhaust device.   One of the inner surface side protruding portion and the outer surface side protruding portion is formed integrally with the cover main body, and the other is formed separately from the cover main body and then fixed to the cover main body. The exhaust device cover for an internal combustion engine according to claim 2.

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