JP2021004573A - Exhaust system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the detection accuracy of a sensor attached to an exhaust pipe in a vehicle in which an engine is arranged closer to one side from the center in the vehicle width direction. SOLUTION: An exhaust manifold 13 for guiding exhaust gas from an engine 11 arranged on the right side of the vehicle diagonally to the rear of the vehicle, a curved pipe 14 for changing the flow of exhaust gas flowing from the exhaust manifold 13 to the rear of the vehicle, and the like. In the exhaust system 100 including an exhaust pipe 15 connected to the downstream of the exhaust gas flow of the curved pipe 14 and extending toward the rear of the vehicle, and a sensor 20 arranged in the exhaust pipe 15, the sensor 20 is It is inserted into the exhaust pipe 15 from the left side of the vehicle, and the exhaust pipe 15 has a protruding portion 18 whose inner surface projects toward the right side on the upstream side of the sensor 20 on the left wall 16. [Selection diagram] Fig. 2

Description

The present invention relates to the structure of an exhaust system that guides the exhaust gas from the internal combustion engine to the rear of the vehicle.

Conventionally, a sensor for detecting the state of the internal exhaust gas is attached to an exhaust member for guiding the exhaust gas from the engine of a vehicle, for example, an exhaust manifold or an exhaust pipe.

For example, Patent Document 1 proposes a structure in which the tip of a sensing portion of a sensor that detects an oxygen concentration is arranged at the center of an exhaust pipe.

Japanese Unexamined Patent Publication No. 2006-70794

By the way, in a vehicle, the engine may be arranged closer to one side from the center in the vehicle width direction. On the other hand, the exhaust pipe is often arranged at the center of the vehicle in the width direction. In this case, since the exhaust gas from the engine does not flow straight into the exhaust pipe, the detection accuracy of the sensor may be insufficient even if the tip of the sensor is arranged at the center of the exhaust pipe.

Therefore, an object of the present invention is to improve the detection accuracy of the sensor attached to the exhaust pipe in a vehicle in which the engine is arranged closer to one side from the center in the vehicle width direction.

The exhaust system of the present invention includes an exhaust manifold that guides exhaust gas from an internal combustion engine that is arranged so as to be shifted to the first side from the center in the vehicle width direction diagonally to the rear of the vehicle, and an exhaust manifold that is arranged on the vehicle width direction center side from the exhaust manifold. A curved pipe that changes the flow of exhaust gas flowing from the exhaust manifold to the rear of the vehicle, an exhaust pipe that is connected to the downstream of the exhaust gas flow of the bent pipe and extends toward the rear of the vehicle, and the exhaust pipe. An exhaust system including a sensor arranged therein, wherein the sensor is inserted into the exhaust pipe from a second side opposite to the first side, and the exhaust pipe is the exhaust pipe. It is characterized in that the inner surface of the wall on the second side has a protrusion protruding toward the first side on the upstream side of the sensor.

When the internal combustion engine is displaced from the center in the width direction of the vehicle to the first side, the exhaust gas of the internal combustion engine is guided diagonally rearward of the vehicle by the exhaust manifold. The flow of exhaust gas is changed from diagonally rearward to the rear of the vehicle by a curved pipe and flows into the exhaust pipe. Therefore, the flow of the exhaust gas flows into the exhaust pipe in a state of being biased toward the outer peripheral side of the bent pipe, that is, the second side opposite to the first side. The sensor is inserted into the exhaust pipe from the second side, and the exhaust pipe has a protrusion on the upstream side of the sensor on the wall on the second side so that the inner surface projects toward the first side. Therefore, the flow of the exhaust gas biased to the second side hits the protruding portion, faces the first side, and flows through the center of the exhaust pipe. As a result, the mainstream portion of the exhaust gas flows around the sensor, and the detection accuracy of the sensor can be improved.

INDUSTRIAL APPLICABILITY The present invention can improve the detection accuracy of the sensor attached to the exhaust pipe in a vehicle in which the engine is arranged closer to one side from the center in the vehicle width direction.

It is a top view of the exhaust system of an embodiment. It is an enlarged sectional view of the part A of FIG.

Hereinafter, the exhaust system 100 of the embodiment will be described with reference to the drawings. The arrows FR and RH shown in each figure indicate the front direction (traveling direction) and the right direction of the vehicle 10, respectively. Further, the opposite directions of the arrows FR and RH indicate the vehicle rear direction and the left direction. Hereinafter, when the description is simply made using the front-rear direction and the left-right direction, the front-rear direction in the vehicle front-rear direction and the left-right direction in the vehicle left-right direction (vehicle width direction) are used unless otherwise specified.

As shown in FIG. 1, in the vehicle 10 to which the exhaust system 100 is attached, the engine 11 which is an internal combustion engine is mounted closer to the right side in the vehicle width direction on the first side. The engine 11 has four cylinders, and the cylinder exhaust pipes 12 connected to each cylinder extend to the rear of the vehicle. Each cylinder exhaust pipe 12 is assembled in one pipe and connected to the exhaust manifold 13. The exhaust manifold 13 is a straight pipe having a diameter larger than that of the cylinder exhaust pipe 12, and extends diagonally rearward of the vehicle. Although the exhaust system 100 of the present embodiment will be described as being connected to the 4-cylinder engine 11, it may be connected to the engine 11 having another number of cylinders.

Downstream of the exhaust gas flow direction of the exhaust manifold 13, a curved pipe 14 is arranged on the center side in the vehicle width direction of the exhaust manifold 13 and changes the exhaust gas flow direction from the diagonal rear of the vehicle to the rear of the vehicle. ing. The downstream end of the curved pipe 14 extends in the direction along the center line 91 in the width direction of the vehicle 10. An exhaust pipe 15 extending toward the rear of the vehicle is connected to the downstream side of the exhaust gas flow of the curved pipe 14. The exhaust pipe 15 is arranged at the center in the width direction of the vehicle, and the center line 92 of the exhaust pipe 15 extends toward the rear of the vehicle along the center line 91 in the width direction of the vehicle 10.

A sensor 20 for detecting the state of exhaust gas is attached to the exhaust pipe 15 immediately downstream of the bent pipe 14. The sensor 20 may be, for example, an air-fuel ratio sensor.

As shown in FIG. 2, a sensor mounting seat whose inner surface projects to the right toward the center line 92 of the exhaust pipe 15 on the wall 16 on the left side of the exhaust pipe 15 which is the outer peripheral side of the exhaust gas flow of the curved pipe 14. 17 is provided.

The sensor 20 is composed of a main body 21, a mounting flange 22, and a sensing unit 23. The sensor 20 is inserted into the exhaust pipe 15 from the left side of the vehicle 10 which is the second side opposite to the first side at the center of the sensor mounting seat 17 provided on the exhaust pipe 15. The mounting flange 22 of the sensor 20 is connected to the outer surface of the sensor mounting seat 17. The sensing portion 23 at the tip extends to the vicinity of the center line 92 of the exhaust pipe 15. The upstream portion of the sensor 20 of the sensor mounting seat 17 constitutes a protruding portion 18 whose inner surface projects to the right on the upstream side of the sensor 20.

In the exhaust system 100 configured as described above, the exhaust gas from the engine 11 that has flowed from each cylinder exhaust pipe 12 to the exhaust manifold 13 flows diagonally rearward of the vehicle. The direction of the exhaust gas flow is changed from diagonally rearward to the rear of the vehicle by the curved pipe 14. As a result, as shown in FIG. 2, the flow of the exhaust gas in the bent pipe 14 is biased to the left side, which is the outer peripheral side of the bent pipe 14. Then, the exhaust gas flow flows into the downstream exhaust pipe 15 in a state of being biased to the left side of the vehicle. Therefore, in the exhaust pipe 15 immediately downstream of the bent pipe 14, the main stream 30 of the exhaust gas flows along the inner surface of the left wall 16.

The main stream 30 of the exhaust gas that has flowed along the inner surface of the wall 16 hits the protrusion 18 and the direction of the flow is directed to the right so that the exhaust gas flows in the vicinity of the center line 92 of the exhaust pipe 15. As a result, the mainstream 30 of the exhaust gas flows around the sensing portion 23 at the tip of the sensor 20, and the detection accuracy of the sensor 20 is improved.

As described above, the exhaust system 100 of the embodiment can improve the detection accuracy of the sensor 20 attached to the exhaust pipe 15 in the vehicle 10 in which the engine 11 is arranged closer to one side from the center in the vehicle width direction. it can.

Further, by improving the detection accuracy of the sensor 20, the combustion control accuracy of the engine 11 can be improved.

In the exhaust system 100 of the embodiment described above, the exhaust pipe 15 has been described as being arranged at the center in the vehicle width direction, but the exhaust pipe 15 may be arranged at a deviation from the center in the vehicle width direction. Further, in the exhaust system 100, the portion of the sensor mounting seat 17 on the upstream side of the sensor 20 has been described as forming the protruding portion 18, but the present invention is not limited to this, and the inner surface of the sensor mounting seat 17 projects to the right on the upstream side. A convex portion may be provided separately.

Further, in the exhaust system 100, although it has been described that the engine 11 is mounted on the right side in the vehicle width direction, it can be applied to the vehicle 10 in which the engine 11 is mounted on the left side in the vehicle width direction. In this case, the first side is on the left side in the vehicle width direction, and the second side is on the right side in the vehicle width direction.

10 vehicle, 11 engine, 12 cylinder exhaust pipe, 13 exhaust manifold, 14 bent pipe, 15 exhaust pipe, 16 wall, 17 sensor mounting seat, 18 protrusion, 20 sensor, 21 main body, 22 mounting flange, 23 sensing part, 30 mainstream, 91,92 centerline, 100 exhaust system.

Claims (1)

An exhaust manifold that guides exhaust gas from an internal combustion engine located on the first side of the center in the vehicle width direction diagonally to the rear of the vehicle,
A curved pipe arranged on the center side in the vehicle width direction with respect to the exhaust manifold and changing the flow of exhaust gas flowing in from the exhaust manifold to the rear of the vehicle.
An exhaust pipe connected to the downstream of the exhaust gas flow of the curved pipe and extending toward the rear of the vehicle,
An exhaust system including a sensor arranged in the exhaust pipe.
The sensor is inserted into the exhaust pipe from the second side opposite to the first side.
The exhaust pipe has a protrusion whose inner surface projects toward the first side on the upstream side of the sensor on the second wall.
An exhaust system featuring.

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