Heat shielding structure of internal combustion engine

Abstract

To provide a heat shielding structure of an internal combustion engine capable of protecting a connector from radiation heat of an exhaust member while simplifying wiring of a harness.SOLUTION: A heat shielding structure of an engine 1 has a heat shielding plate 12. The heat shielding plate 12 is attached to a front wall 4A of a cylinder head cover 4 above an exhaust member 6. An air-fuel ratio sensor 10 and an oxygen sensor 11 are attached to the heat shielding plate 12. The heat shielding plate 12 has a heat shielding part 14A that separates the air-fuel ratio sensor 10 and the oxygen sensor 11 from the exhaust member 6. The heat shielding part 14A has a fixing piece 14g that fixes a harness 11B of the oxygen sensor 11 to the heat shielding part 14A.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a heat insulating structure for an internal combustion engine. [Background technology]

[0002] Conventionally, a sensor connector is attached to an engine via a harness bracket in order to prevent the sensor connector connected to an exhaust member from being subjected to heat from the exhaust member (see Patent Document 1).

[0003] This harness bracket has a heat-shielding portion that insulates the sensor connector from heat, and a fixing portion that is connected to the heat-shielding portion and fixed to the engine, and fixes other harnesses that are arranged parallel to the harness to the heat-shielding portion.

[0004] The harness bracket is attached to the intake side of the cylinder head cover relative to the exhaust side of the cylinder head cover where the exhaust manifold is located.

[0005] The harness is routed from the exhaust side to the intake side of the cylinder head, and the heat shield is disposed between the harness connector and the cylinder head cover in the front-rear direction.

[0006] This makes it possible to prevent thermal deterioration of the harness connectors due to hot air from the exhaust manifold, which is maintained at a high temperature. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2007-186147 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the conventional harness bracket, since it is not provided directly above the exhaust manifold, it is not possible to effectively protect the connector from the radiant heat rising from the exhaust manifold.

[0009] In addition, since the conventional harness bracket is located on the intake side of the cylinder head cover, opposite the exhaust manifold side, it is necessary to extend the harness from the sensor attached to the exhaust manifold to the harness bracket, which makes the harness longer and increases the risk of interference between the harness bracket and the harness, making the wiring of the harness more complicated.

[0010] The present invention has been made in response to the above-mentioned problems, and aims to provide a heat shielding structure for an internal combustion engine that can protect connectors from radiant heat from exhaust members while simplifying the wiring of the harness. [Means for solving the problem]

[0011] The present invention is a heat shielding structure for an internal combustion engine comprising an exhaust member attached to a side wall of the internal combustion engine, a heat shielding plate for protecting the internal combustion engine from the heat of the exhaust member, and at least one sensor device for detecting the state of exhaust gas flowing through the exhaust member, wherein the sensor device has a sensor main body attached to the exhaust member and a connector connected to the sensor main body via a harness, wherein the heat shielding plate is attached to the side wall of the internal combustion engine above the exhaust member, the connector is attached to the heat shielding plate, the heat shielding plate has a heat shielding portion that separates the connector and the exhaust member, and the heat shielding portion has a fixing portion that fixes the harness of at least one of the sensor devices to the heat shielding portion. Effect of the Invention

[0012] As described above, according to the present invention, the wiring of the harness can be simplified, and the connector can be protected from the radiant heat of the exhaust member. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a front view of an engine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a front view of the upper part of an engine according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a top view of a heat shield plate and its periphery of an engine according to an embodiment of the present invention. [Figure 4] FIG. 4 is a front view of a heat shield according to an embodiment of the present invention. [Diagram 5] FIG. 5 is a right side view of a heat shield according to one embodiment of the present invention. [Figure 6] FIG. 6 is a bottom view of a heat shield according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A heat shielding structure for an internal combustion engine in one embodiment of the present invention comprises an exhaust member attached to a side wall of the internal combustion engine, a heat shielding plate that protects the internal combustion engine from the heat of the exhaust member, and at least one sensor device that detects the state of exhaust gas flowing through the exhaust member, wherein the sensor device has a sensor main body attached to the exhaust member and a connector connected to the sensor main body via a harness, wherein the heat shielding plate is attached to the side wall of the internal combustion engine above the exhaust member, the connector is attached to the heat shielding plate, the heat shielding plate has a heat shielding portion that separates the connector and the exhaust member, and the heat shielding portion has a fixing portion that fixes the harness of at least one sensor device to the heat shielding portion.

[0015] As a result, the heat shield structure for an internal combustion engine according to one embodiment of the present invention can protect the connector from radiant heat from the exhaust member while simplifying the wiring of the harness. EXAMPLES

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a heat insulating structure for an internal combustion engine according to the present invention will be described with reference to the drawings. 1 to 6 are diagrams showing a heat insulating structure for an internal combustion engine according to one embodiment of the present invention.

[0017] 1 to 6, the up, down, front, rear, left and right directions are defined as the front-to-rear direction of the vehicle based on the engine installed in the vehicle, with the side on which the catalytic converter is installed being the front and the side opposite the catalytic converter being the rear.

[0018] The left-right direction of the vehicle (widthwise direction) is defined as the left-right direction, with the chain case side being the right and the side opposite the chain case being the left. The height direction of the engine is defined as the up-down direction, with the cylinder head cover side being the top and the oil pan side being the bottom.

[0019] First, the configuration will be described. As shown in FIG. 1, a vehicle is provided with an engine 1 as an internal combustion engine. The engine 1 includes a cylinder block 2, a cylinder head 3, a cylinder head cover 4, and an oil pan 5.

[0020] The cylinder block 2 is provided with a plurality of cylinders (not shown), which are arranged side by side in the left-right direction of the engine 1. Each cylinder houses a piston (not shown), and the pistons are connected to a crankshaft (not shown) via a connecting rod (not shown).

[0021] The piston reciprocates within the cylinder, thereby rotating the crankshaft via the connecting rod.

[0022] The cylinder head 3 is attached to the upper part of the cylinder block 2, and is formed with a plurality of intake ports (not shown) and a plurality of exhaust ports (not shown).

[0023] The intake port and exhaust port are connected to the cylinders. The intake port introduces intake air into the cylinder, and the exhaust port discharges exhaust gas from the cylinder.

[0024] An exhaust member 6 is connected to the front side of the cylinder head 3. The exhaust member 6 has an upstream pipe 7 whose upstream end is connected to the front wall 3A of the cylinder head 3, a catalyst case 8 connected to the downstream end of the upstream pipe 7, and a downstream pipe 9 connected to the downstream end of the catalyst case 8.

[0025] Here, upstream and downstream refer to the upstream and downstream in the direction in which exhaust gas flows. For example, the upstream pipe 7 is located upstream of the catalyst case 8, and the catalyst case 8 is located downstream of the upstream pipe 7.

[0026] An exhaust manifold (not shown) is formed inside the cylinder head 3 at the front of the cylinder head 3, and exhaust gas discharged from the exhaust ports is collected by the exhaust manifold and then discharged to the upstream pipe 7.

[0027] A three-way catalyst is provided inside the catalyst case 8. The three-way catalyst purifies the exhaust gas by oxidizing carbon monoxide and unburned hydrocarbons contained in the exhaust gas and converting them into carbon dioxide (CO2) and water vapor (H2O), and by reducing nitrogen oxides and converting them into nitrogen (N2).

[0028] The exhaust gas purified in the catalyst case 8 is discharged to the downstream piping 9. An exhaust pipe (not shown) is connected to the downstream end of the downstream piping 9, and the exhaust gas discharged from the downstream piping 9 to the exhaust pipe is discharged to the atmosphere by the exhaust pipe.

[0029] An air-fuel ratio sensor 10 is provided in the upstream pipe 7, and the air-fuel ratio sensor 10 detects the air-fuel ratio of the exhaust gas and outputs the detection information to a controller (not shown).

[0030] An oxygen sensor 11 is provided in the downstream pipe 9, and the oxygen sensor 11 detects the oxygen concentration in the exhaust gas and outputs the detection information to a controller (not shown). In other words, the air-fuel ratio sensor 10 and the oxygen sensor 11 detect the state of the exhaust gas flowing through the exhaust member 6.

[0031] The air-fuel ratio sensor 10 has a sensor body 10A attached to the upstream pipe 7, a harness 10B attached to one end of the sensor body 10A, and a connector 10C attached to the other end of the harness 10B.

[0032] The sensor body 11A attached to the downstream pipe 9 has a harness 11B attached to one end of the sensor body 11A and a connector 11C attached to the other end of the harness 11B. The air-fuel ratio sensor 10 and the oxygen sensor 11 of this embodiment constitute a sensor.

[0033] 1, a chain case 1A is attached to the right ends of the cylinder block 2, cylinder head 3, and cylinder head cover 4, and covers a timing chain (not shown) from the right. The timing chain transmits the rotation of the crankshaft to an intake shaft and an exhaust shaft (not shown) that are provided in the cylinder head 3 and the cylinder head cover 4.

[0034] 1 and 2, a heat shield 12 is attached to the front wall 4A of the resin cylinder head cover 4, and the heat shield 12 is located above the exhaust member 6. In other words, the heat shield 12 is attached to the front wall 4A of the engine 1 on the side where the exhaust member 6 is disposed. The front wall 4A of this embodiment forms a side wall of the internal combustion engine.

[0035] 2, the heat shield 12 has an attachment portion 13 and an extension portion 14. The attachment portion 13 has bolt holes 13a, 13b through which bolts (not shown) are inserted, and the attachment portion 13 is fixed to the front wall 4A of the cylinder head cover 4 by fastening the bolts to the front wall 4A of the cylinder head cover 4 through the bolt holes 13a, 13b.

[0036] As shown in FIGS. 3 and 4, the upper end of the mounting portion 13 is provided with a curved portion 13c, which is bent forward from the upper end of the mounting portion 13.

[0037] An air cleaner (not shown) is attached to the upper part of the cylinder head cover 4, and the curved portion 13c is located between the exhaust member 6 and the air cleaner. As a result, the radiant heat rising from the exhaust member 6 is blocked by the curved portion 13c, and the air cleaner can be protected from the heat of the exhaust member 6.

[0038] Furthermore, the radiant heat rising from the exhaust member 6 is blocked by the mounting portion 13 and the curved portion 13c, so that the cylinder head cover 4 can be protected from the heat of the exhaust member 6.

[0039] The extension portion 14 extends from the attachment portion 13 to the right in the vehicle width direction (hereinafter referred to as the vehicle width direction) so as to move away from the exhaust member 6, and is located diagonally above and to the right of the exhaust member 6. In Figure 4, the boundary 14a between the attachment portion 13 and the extension portion 14 is indicated by a thick line.

[0040] As shown in Fig. 4, the extension portion 14 is provided with mounting holes 14b, 14c spaced apart in the vertical direction, and clips 10a, 11a formed on the rear surfaces of the connectors 10C, 11C are fitted into the mounting holes 14b, 14c, thereby fixing the connectors 10C, 11C to the extension portion 14 (see Fig. 3).

[0041] As shown in Figures 1 and 3, the extension portion 14 is provided with a heat shield 14A, which protrudes from the lower end of the extension portion 14 on the side away from the engine 1 (toward the front of the engine 1).

[0042] That is, the heat shield 14A is located on the opposite side of the extension portion 14 from the engine 1, and extends from the extension portion 14 to the opposite side of the engine 1.

[0043] Heat shield 14A covers connectors 10C, 11C from below so as to separate connectors 10C, 11C from exhaust member 6 in the vertical direction (see FIG. 3).

[0044] That is, connectors 10C and 11C are attached to extension portion 14 so as to be located on the opposite side of extension portion 14 from engine 1 and above heat shield portion 14A.

[0045] The heat shield 14A is provided with a fixing piece 14g, which protrudes from the front end of the heat shield 14A toward the side away from the engine 1.

[0046] As shown in FIG. 2, a fixing device 15 is attached to the harness 11B of the connector 11C of the oxygen sensor 11, and the fixing device 15 is attached to a fixing piece 14g.

[0047] As a result, the harness 11B is fixed to the heat shield 14A via the fixing piece 14g. The fixing piece 14g in this embodiment constitutes a fixing portion.

[0048] 2 and 4, a curved portion 14d is formed in the heat shield 14A. The curved portion 14d is curved downward from the end (right end) of the heat shield 14A that is farthest from the exhaust member 6 in the vehicle width direction, and is located below the connector 11C.

[0049] 3 and 6, extension portion 14 is inclined so as to move away from engine 1 in the vehicle width direction from mounting portion 13. In other words, extension portion 14 is inclined so that the end portion on the exhaust member 6 side in the vehicle width direction approaches engine 1, and the end portion on the side away from exhaust member 6 moves away from engine 1.

[0050] An extension portion 14e is formed in the heat shielding portion 14A. The extension portion 14e extends from a lower end of a boundary 14a between the mounting portion 13 and the expansion portion 14 in the vehicle width direction of the heat shielding portion 14A to the mounting portion 13. In Fig. 6, a boundary 14n between the heat shielding portion 14A and the extension portion 14e is indicated by a dashed line.

[0051] As shown in Figures 4 and 5, a bead-shaped reinforcing portion 14f is formed from the boundary 14a between the mounting portion 13 and the expansion portion 14 toward the expansion portion 14, and the boundary 14a between the mounting portion 13 and the expansion portion 14 is reinforced by the reinforcing portion 14f.

[0052] In other words, the extension portion 14 is inclined at the boundary 14a relative to the mounting portion 13 so as to move away from the engine 1. By reinforcing the boundary 14a with the reinforcing portion 14f, it is possible to suppress vibration of the extension portion 14 due to vibration of the engine 1, and it is possible to improve the supporting rigidity of the extension portion 14 for the connectors 10C, 11C.

[0053] Next, the effect of the heat insulating structure of the engine 1 according to this embodiment will be described. The heat shielding structure of the engine 1 in this embodiment includes an exhaust member 6 attached to the front wall 3A of the cylinder head 3, a heat shielding plate 12 that protects the cylinder head cover 4 and the air cleaner from the heat of the exhaust member 6, and an air-fuel ratio sensor 10 and an oxygen sensor 11 that detect the state of the exhaust gas flowing through the exhaust member 6.

[0054] The air-fuel ratio sensor 10 has a sensor body 10A attached to the upstream piping 7 and a connector 10C connected to the sensor body 10A via a harness 10B, and the oxygen sensor 11 has a sensor body 11A attached to the downstream piping 9 and a connector 11C connected to the sensor body 11A via a harness 11B.

[0055] The heat shield 12 is attached to the front wall 4A of the cylinder head cover 4 above the exhaust member 6, and the air-fuel ratio sensor 10 and the oxygen sensor 11 are attached to the heat shield 12.

[0056] The heat shield 12 has a heat shield 14A that separates the air-fuel ratio sensor 10 and the oxygen sensor 11 from the exhaust member 6, and the heat shield 14A has a fixing piece 14g that fixes the harness 11B of the oxygen sensor 11 to the heat shield 14A.

[0057] This allows the heat shield 14A to block the radiant heat rising from the exhaust member 6 (see radiant heat W1 in FIG. 2), thereby protecting the connector 10C of the air-fuel ratio sensor 10 and the connector 11C of the oxygen sensor 11 from the heat of the exhaust member 6.

[0058] Furthermore, even if the exhaust member 6 and the connectors 10C, 11C are arranged above the exhaust member 6, on the front wall (front walls 3A, 4A) side of the engine 1, the connectors 10C, 11C can be protected from the heat of the exhaust member 6, so the harnesses 10B, 11B can be shortened and routed.

[0059] In addition, by fixing the harness 11B of the oxygen sensor 11 to the heat shield 14A, the harnesses 10B and 11B can be routed while preventing interference between the harness 11B and the heat shield 14A.

[0060] As a result of the above, the wiring of the harnesses 10B and 11B can be simplified.

[0061] In addition, according to the heat shielding structure of the engine 1 in this embodiment, the heat shielding plate 12 has a mounting portion 13 attached to the front wall 4A of the cylinder head cover 4 directly above the exhaust member 6, and an extension portion 14 that is continuous with the mounting portion 13 and extends from the mounting portion 13 in the vehicle width direction so as to move away from the exhaust member 6.

[0062] The heat shielding portion 14A is located on the opposite side of the extension portion 14 from the engine 1 and extends from the extension portion 14 to the opposite side of the engine 1, and the connectors 10C, 11C are attached to the extension portion 14 so as to be located on the opposite side of the extension portion 14 from the engine 1 and above the heat shielding portion 14A.

[0063] This allows the connectors 10C, 11C to be located away from the engine 1, and the radiant heat generated by the engine 1 can be blocked by the extension portion 14, thereby protecting the connectors 10C, 11C from the heat of the engine 1.

[0064] In other words, the heat shield 12 of this embodiment can effectively protect the connectors 10C, 11C from both the heat of the exhaust member 6 and the heat of the engine 1.

[0065] Furthermore, according to the heat shielding structure of the engine 1 of this embodiment, a curved portion 14d is formed in the heat shielding portion 14A, and the curved portion 14d is curved downward from the end of the heat shielding portion 14A that is farthest from the exhaust member 6 in the vehicle width direction.

[0066] As a result, the curved portion 14d prevents the radiant heat rising from the exhaust member 6 from flowing around the underside of the heat-shielding portion 14A to the connectors 10C, 11C (see radiant heat W2 in Figure 2), thereby more effectively protecting the connectors 10C, 11C from the heat of the exhaust member 6.

[0067] Furthermore, according to the heat insulating structure for the engine 1 of this embodiment, the extension portion 14 is inclined so as to move away from the engine 1 as it moves from the attachment portion 13 in the vehicle width direction.

[0068] In addition, an extension 14e is formed in the heat shield 14A, and the extension 14e extends from a lower end of a boundary 14a between the attachment portion 13 and the extension 14e in the vehicle width direction of the heat shield 14A to the attachment portion 13.

[0069] As a result, the extension portion 14e allows the heat shield portion 14A to be positioned closer to the exhaust member 6 side and closer to the engine 1 side (see FIG. 3).

[0070] Therefore, the gap in the front-rear direction between the engine 1 and heat shield 14A can be reduced by extension 14e, and heat shield 14A can more effectively block the radiant heat rising from exhaust member 6. As a result, connectors 10C, 11C can be more effectively protected from the heat of exhaust member 6.

[0071] In this embodiment, the oxygen sensor 11 is fixed to the heat insulating portion 14A, but both the air-fuel ratio sensor 10 and the oxygen sensor 11 may be fixed to the heat insulating portion 14A.

[0072] Although an embodiment of the invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made without departing from the spirit and scope of the invention, and all such modifications and equivalents are intended to be encompassed by the following claims. [Explanation of symbols]

[0073] 1...engine, 4A...front wall (side wall of internal combustion engine), 6...exhaust member, 10...air-fuel ratio sensor (sensor), 10A, 11A...sensor body, 10B, 11B...harness, 10C, 11C...connector, 11...oxygen sensor (sensor), 14a...boundary (boundary between mounting portion and extension portion), 12...heat shield, 13...mounting portion, 14...extension portion, 14d...curved portion, 14e...extension portion, 14g...fixing piece (fixing portion)

Claims

1. an exhaust member attached to a side wall of an internal combustion engine; a heat shield for protecting the internal combustion engine from heat of the exhaust member; and at least one sensor device for detecting a state of exhaust gas flowing through the exhaust member; The sensor device includes a sensor body attached to the exhaust member and a connector connected to the sensor body via a harness, The heat shield is attached to the side wall of the internal combustion engine above the exhaust member, The connector is attached to the heat shield, the heat shield has a heat shield portion that separates the connector and the exhaust member, 13. A heat insulating structure for an internal combustion engine, wherein the heat insulating portion has a fixing portion for fixing a harness of at least one of the sensor devices to the heat insulating portion.

2. the heat shield has an attachment portion attached to the side wall of the internal combustion engine directly above the exhaust member, and an extension portion that is continuous with the attachment portion and extends from the attachment portion in a vehicle width direction so as to be away from the exhaust member, The heat shield is located on a side opposite to the internal combustion engine with respect to the extension portion and extends from the extension portion to a side opposite to the internal combustion engine, 2. The heat insulating structure for an internal combustion engine according to claim 1, wherein the connector is attached to the extension portion so as to be located on the opposite side of the extension portion from the internal combustion engine and above the heat insulating portion.

3. A curved portion is formed in the heat shield, 2. The heat insulating structure for an internal combustion engine according to claim 1, wherein the curved portion is curved downward from an end portion of the heat insulating portion which is farthest from the exhaust member in a vehicle width direction.

4. A curved portion is formed in the heat shield, 3. The heat insulating structure for an internal combustion engine according to claim 2, wherein the curved portion is curved downward from an end portion of the heat insulating portion which is farthest from the exhaust member in a vehicle width direction.

5. The extension portion is inclined so as to move away from the internal combustion engine as it extends in a vehicle width direction from the attachment portion, An extension is formed in the heat shield, 5. The heat shield structure for an internal combustion engine according to claim 2, wherein the extension portion extends from a lower end of a boundary between the attachment portion and the extension portion in the vehicle width direction of the heat shield portion to the attachment portion.

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