JPH09177564A - Heat insulator of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge fluids such as engine oil without dropping the fluid to an exhaust pipe during maintenance by forming an opening window for covering the exhaust pipe, a bead extended so as to have a bent section and a guiding means in this bead. SOLUTION: A heat insulator 1 for covering an exhaust manifold has 5 attaching seats 11 to 15 and is connected to the exhaust manifold via bolts penetrating the attaching seats 11 to 15. An opening window 10 is formed in order to attach an O2 sensor to the exhaust manifold and an outer peripheral bead 21 protruded to the outside from the surroundings is formed in the heat insulator 1. Four projecting beads 31 to 34 and two recessed beads 41 and 42 are formed in order to discharge oil or the like dropped to the heat insulator 1 without bringing the oil or the like into contact with the exhaust manifold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a heat shield device for covering an exhaust pipe of an engine.

[0002]

2. Description of the Related Art In an engine for an automobile, a heat insulator is provided as a heat shield cover for covering an exhaust manifold (exhaust pipe), which has a considerably high temperature, so that heat release from the exhaust manifold is blocked and temperature rise in an engine room is suppressed. (Actual Kaihei 2-22
620, Japanese Patent Laid-Open No. 5-332135.

As a conventional heat shield device for an engine, there is one as shown in FIGS. 8 and 9, for example.

To explain this, the heat insulator 1 has a shape covering an exhaust manifold (not shown). One opening window 10 is formed in the heat insulator 1. Open window 10 to O ₂ sensor 2
Is inserted.

A plurality of convex beads 51 to 58 are formed on the heat insulator 1. Each of the convex beads 51 to 58 is formed so that its cross section protrudes from the outer wall of the heat insulator 1, and extends in the horizontal direction or the vertical direction in the side view of FIG.

The sheet metal heat insulator 1 is provided with the convex beads 51 to 58, so that the rigidity of the heat insulator 1 is increased and the occurrence of membrane vibration or the like can be suppressed.

[0007]

By the way, when a combustible component such as engine oil or antifreeze in engine cooling water adheres to the exhaust manifold during maintenance of the engine, etc., the exhaust manifold 3 becomes hot during engine operation. There is a possibility that smoke and offensive odor will be generated.

However, in the above-described conventional heat shield device for an engine, after oil etc. dripping on the heat insulator 1 is accumulated in the convex beads 58 etc., it flows down on the heat insulator 1 and enters the opening window 10. There is a possibility of dripping from the opening window 10 to the exhaust manifold.

An object of the present invention is to solve the above problems and to provide a heat shield device for an engine in which oil or the like is prevented from coming into contact with the exhaust pipe during maintenance or the like.

[0010]

According to a first aspect of the present invention, there is provided a heat shield device for an engine, comprising a heat insulator covering an exhaust pipe, wherein the heat insulator has an opening window located above the exhaust pipe, and the heat insulator is provided in the heat insulator. The bead is provided with a bent cross section with respect to the outer surface thereof, and the bead is provided with guide means for guiding the fluid flowing down on the heat insulator so as not to enter the opening window.

The heat shield device for an engine according to claim 2 is
In the invention according to claim 1, as the guide means, a bead is lowered from above the opening window to the side.

The heat shield device for an engine according to claim 3 is
In the invention according to claim 1 or 2, as the guide means, a concave bead that is recessed with respect to the outer surface of the heat insulator is extended laterally of the opening window so as to be convex with respect to the outer surface of the heat insulator. The bulging convex bead is lowered from above the opening window and connected to the concave bead.

The heat shield device for an engine according to claim 4 is
A heat insulator covering the exhaust pipe is provided, and an opening window located above the exhaust pipe is formed in the heat insulator,
An outer peripheral bead that projects so as to prevent the fluid flowing down on the heat insulator from entering the opening window is projected around the opening window.

A heat shield device for an engine according to claim 5 is
In the invention according to claim 4, a sensor attached to the exhaust pipe is provided from the opening window, and the outer peripheral bead is projected lower than a base end portion of the sensor protruding outward from the heat insulator.

[0015]

In the heat shield apparatus for an engine according to claim 1, when fluid such as engine oil or engine cooling water drips onto the heat insulator at the time of maintenance of the engine, the fluid is blocked by the bead and the heat insulator. By flowing down through the beads, it is discharged without dropping into the exhaust pipe. In this way, flammable components such as engine oil and antifreeze in engine cooling water are prevented from adhering to the exhaust pipe, and smoke and offensive odors can be prevented from occurring as the exhaust pipe becomes hot during engine operation. .

In the engine heat shield of claim 2, since the bead is inclined, the oil and the like held by the bead is promptly discharged without accumulating in the bead.

In the heat shield device for the engine according to the third aspect, since the convex bead is inclined, the oil and the like held by the convex bead flows down quickly without accumulating in the convex bead. The oil or the like flowing down along the convex bead passes through the concave bead and is discharged from the downstream end of the concave bead without dropping on the exhaust pipe.

In the heat shield device for an engine according to claim 4, when fluid such as engine oil or engine cooling water drips on the heat insulator during maintenance of the engine, the fluid is blocked by the outer peripheral bead, By flowing down on the insulator via the outer peripheral bead,
It is discharged from the opening window without dripping into the exhaust pipe. In this way, flammable components such as engine oil and antifreeze in engine cooling water are prevented from adhering to the exhaust pipe, and smoke and offensive odors can be prevented from occurring as the exhaust pipe becomes hot during engine operation. .

In the engine heat shield of claim 5, since the outer peripheral bead does not cover the sensor protruding outside the outer surface of the heat insulator, durability can be maintained without impairing the heat dissipation of the sensor. .

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 and 3, the heat insulator 1 has a shape that covers the exhaust manifold 3.

The exhaust manifold 3 is connected to the side wall of the engine body and collects the exhaust gas discharged from each cylinder and guides it to the exhaust pipe on the downstream side.

The heat insulator 1 functions as a heat shield cover for covering the exhaust manifold 3 which is heated to a considerably high temperature, and blocks heat radiation from the exhaust manifold 3 to suppress the temperature rise in the engine room.

As shown in FIG. 2, the heat insulator 1 is provided with five mounting seats 11 to 15. The heat insulator 1 is fastened to the exhaust manifold 3 via bolts penetrating the mounting seats 11 to 15. Each of the mounting seats 11 to 14 is formed by bulging in a circular trapezoidal shape. The mounting seat 15 is formed in a circular concave shape.

In FIG. 3, reference numeral 2 is an O ₂ sensor attached to the exhaust manifold 3. O ₂ sensor 2
Has its detection section facing the exhaust passage and outputs a signal corresponding to the oxygen concentration in the exhaust. A control unit (not shown) inputs a signal from the O ₂ sensor 2 and feedback-controls the fuel injection amount so that the air-fuel mixture has a stoichiometric air-fuel ratio to maintain the conversion efficiency of the three-way catalyst (not shown). It has become.

In order to attach the O ₂ sensor 2 to the exhaust manifold 3, the heat insulator 1 is provided with one opening window 10. Open window 10 to O ₂ sensor 2
Is inserted.

As the opening window provided in the heat insulator 1, a hole through which a pipe or the like for guiding the EGR gas is inserted, or a hole through which a tool for fastening the exhaust manifold is inserted can be considered.

In FIG. 3, 5 is a gland nut fixed to the mounting seat 4 of the exhaust manifold 3 by welding, and 6 is a hexagonal portion formed on the O ₂ sensor 2. The O ₂ sensor 2 is fastened to the ground nut 5 via a tool that engages with the hexagonal portion 6.

By the way, when a combustible component such as engine oil or antifreeze in engine cooling water adheres to the exhaust manifold 3 during maintenance of the engine, smoke and a strange odor are generated as the exhaust manifold 3 becomes hot during engine operation. Can occur.

In order to cope with this, the present invention discharges the oil and the like dropped on the heat insulator 1 so as not to enter the opening window 10. Therefore, the heat insulator 1 has an outer periphery projecting from the periphery of the opening window 10 to the outside. The beads 21 are formed. The outer peripheral bead 21 projects in a tubular shape from the outer wall surface of the heat insulator 1.

The outer peripheral bead 21 serves to prevent oil flowing down on the heat insulator 1 in the circumferential direction so as to avoid the opening window 10 so as to avoid the opening window 10 and drop it from a position where it does not touch the exhaust manifold 3.

Heat insulator 1 of outer peripheral bead 21
The projecting height H of the outer wall surface of the gland nut 5 is set to be lower than the projecting height of the ground nut 5 so as to be lower than the base end portion of the O ₂ sensor 2 projecting outward from the heat insulator 1. As a result, the outer peripheral bead 21 does not cover the hexagonal portion 6 and the like of the O ₂ sensor 2 protruding outward from the ground nut 5.

In this embodiment, the peripheral bead 21
In the heat insulator 1, an opening edge portion of the heat insulator 1 with respect to the opening window 10 is bent into an L-shaped cross section and integrally formed by press working.

As another embodiment, as shown in FIG. 6, an annular member 25 having an L-shaped cross section having an outer peripheral bead 21 is provided separately from the heat insulator 1, and the annular member 25 is welded to the heat insulator 1. You may fix by. In this case, in response to changes in engine specifications,
The shape and mounting position of the outer peripheral bead 21 can be easily changed.

In order to discharge the oil and the like dropped on the heat insulator 1 without touching the exhaust manifold 3, four convex beads 31 to 34 are formed and two concave beads 41 and 42 are formed. It

The heat insulator 1 made of sheet metal has rigidity increased by the beads 31 to 34, 41, 42 whose cross section is bent and extends, so that the occurrence of membrane vibration or the like can be suppressed.

In the side view of FIG. 2, each convex bead 31
To 34 are formed to be inclined.

As guide means for guiding the oil or the like dropped on the heat insulator 1 so as not to enter the opening window 10, the convex beads 31 and 32 are inclined so as to descend from the upper side of the opening window 10 to the side. It is formed. The upper ends of the convex beads 31 and 32 intersect with each other above the opening window 10.

The convex beads 31 and 32 serve to prevent the oil or the like flowing down on the heat insulator 1 toward the opening window 10 so as to be guided so as to avoid the opening window 10 and to drop it from a position where it does not touch the exhaust manifold 3. do.

The inclined lower ends of the convex beads 31, 33, 34 are connected to the concave beads 41, 42, respectively.

In the side view of FIG. 2, each concave bead 4 is
1, 42 extend in the vertical direction. Each concave bead 41, 4
The lower end of 2 is open so as not to be above the exhaust manifold 3.

As shown in FIG. 4, the convex beads 31 to 34 are also provided.
Is bulged in a U-shaped cross section from the outer wall surface of the heat insulator 1 and is integrally formed by pressing.

As another embodiment, as shown in FIG. 7, a strip-shaped member 45 having a convex bead portion 40 and having an L-shaped cross section is provided separately from the heat insulator 1, and the strip-shaped member 45 is provided in the heat insulator 1. It may be fixed by welding. In this case, in response to changes in engine specifications,
The shape and mounting position of the convex bead 40 can be easily changed.

As shown in FIG. 5, the concave beads 41, 42
Is recessed from the outer wall surface of the heat insulator 1 into a U-shaped cross section, and is integrally formed by pressing.

The configuration is as described above. Next, the operation will be described.

When engine oil, engine cooling water, or the like is dropped on the heat insulator 1 during maintenance of the engine or the like, the convex beads 31 to 31 are placed on the heat insulator 1.
By flowing down through 34, the respective concave beads 41, 42, and the outer peripheral beads 21, etc., they are discharged without dropping into the exhaust manifold 3. In this way, flammable components such as engine oil and antifreeze in engine cooling water are prevented from adhering to the exhaust manifold,
It is possible to prevent smoke and a strange odor from being generated as the exhaust manifold 3 becomes hot during engine operation.

Since the upper ends of the respective convex beads 31 and 32 intersect with each other above the opening window 10, the oil or the like flowing down on the heat insulator 1 toward the opening window 10 has the convex beads 31 and 32. It is stopped by one of the above and is discharged while avoiding the opening window 10.

The oil and the like dammed up by the convex beads 31 flow down along the convex beads 31, pass through the concave beads 41, and are discharged from the downstream end of the concave beads 41 onto the exhaust manifold 3 without dropping.

The oil or the like dammed up by the convex bead 32 flows down along the convex bead 32, passes through the concave bead 41, and is discharged from the downstream end of the convex bead 32 onto the exhaust manifold 3 without dropping.

Since each of the convex beads 31 to 34 is inclined, oil or the like is quickly discharged without being accumulated in each of the convex beads 31 to 34. Even if the concave beads are formed instead of the convex beads 31 to 34, the oil or the like can be quickly discharged along the beads.

The outer peripheral bead 21 protrudes in a tubular shape from the periphery of the opening window 10 to the outside, and prevents the oil flowing down on the heat insulator 1 to be guided in the circumferential direction so as to avoid the opening window 10 and the exhaust manifold 3 It is discharged without dropping on top.

Since the outer peripheral bead 21 does not cover the hexagonal portion 6 and the like of the O ₂ sensor 2 protruding outside the ground nut 5, the heat dissipation of the O ₂ sensor 2 is not impaired and the durability can be maintained.

[0053]

As described above, in the engine heat shield according to the first aspect of the present invention, when fluid such as engine oil or engine cooling water drops on the heat insulator during maintenance of the engine, the fluid is It is stopped by the bead and flows down on the heat insulator through the bead, so that it is discharged without dripping into the exhaust pipe, and it prevents smoke and strange odor from occurring as the exhaust pipe becomes hot during engine operation. it can.

The heat shield device for an engine according to claim 2 is
Since the bead is inclined, the oil and the like stopped by the bead is promptly discharged without accumulating in the bead.

The heat shield device for an engine according to claim 3 is
Oil or the like that flows down along the inclined convex bead is quickly discharged through the concave bead without dropping on the exhaust pipe.

The heat shield device for an engine according to claim 4 is:
When fluid such as engine oil or engine cooling water drips onto the heat insulator when servicing the engine,
The fluid is dammed by the outer bead and flows down on the heat insulator through the outer bead, so that the fluid is discharged from the opening window without dripping into the exhaust pipe, and smoke is generated as the exhaust pipe becomes hot during engine operation. It is possible to prevent the generation of an offensive odor.

The heat shield device for an engine according to claim 5 is:
Since the outer peripheral bead does not cover the sensor protruding outward from the outer surface of the heat insulator, the durability can be secured without impairing the heat dissipation of the sensor.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heat insulator showing an embodiment of the present invention.

FIG. 2 is a side view of a heat insulator and the like.

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

FIG. 4 is a sectional view taken along the line BB of FIG. 2;

FIG. 5 is a sectional view taken along line C-C of FIG.

FIG. 6 is a cross-sectional view showing another embodiment.

FIG. 7 is a sectional view showing still another embodiment.

FIG. 8 is a side view of a conventional heat insulator and the like.

9 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heat insulator 2 O ₂ sensor 3 Exhaust manifold 10 Opening window 21 Outer peripheral bead 31 Convex bead 32 Convex bead 33 Convex bead 34 Convex bead 41 Concave bead 42 Concave bead

Claims (5)

[Claims] 1. A heat insulator covering an exhaust pipe is provided, an opening window located above the exhaust pipe is formed in the heat insulator, a bead extending in a bent cross section with respect to an outer surface of the heat insulator is formed, and a bead. A heat shield device for an engine, further comprising guide means for guiding the fluid flowing down on the heat insulator so as not to enter the opening window. 2. A heat shield device for an engine according to claim 1, wherein a bead is lowered from above the opening window to the side as the guide means. 3. As the guide means, a concave bead recessed in a concave shape with respect to the outer surface of the heat insulator is extended laterally of the opening window, and a convex bead protruding in a convex shape with respect to the outer surface of the heat insulator is opened in the opening window. The heat shield device for the engine according to claim 1 or 2, wherein the heat shield device is lowered from above and connected to the concave bead. 4. A heat insulator for covering the exhaust pipe, wherein an opening window located above the exhaust pipe is formed in the heat insulator, and an outer peripheral bead for guiding a fluid flowing down on the heat insulator so as not to enter into the opening window. An engine heat shield characterized by being projected around an opening window. 5. The engine according to claim 4, further comprising a sensor attached to the exhaust pipe through the opening window, wherein the outer peripheral bead is projected lower than a base end portion of the sensor protruding outward from the heat insulator. Heat shield device.