Arrangement Structure of Exhaust Gas Sensor and Motorcycle

Abstract

The present invention is an arrangement structure of an exhaust gas sensor and a motorcycle. The present invention improves exhaust purification performance, and can arrange exhaust gas sensors without impairing the detection accuracy of exhaust gas components. The present invention comprises: an engine (2) having a cylinder (21a) and a cylinder head (21b) disposed in front of a crankcase (20); an exhaust pipe (6) mounted on an exhaust port (22) of the cylinder head; A catalytic device (50) arranged in the middle of the exhaust pipe; and an upstream side sensor (8) attached to the exhaust pipe on the upstream side of the catalytic device. The axis of the cylinder is oriented substantially horizontally, and the exhaust port is provided on the lower side of the cylinder head. The exhaust pipe has a first piping portion (62) extending in the vehicle width direction below the cylinder head. The catalyst device is disposed on the first piping portion so that its axial direction faces the vehicle width direction.

Description

technical field [0001] The invention relates to an arrangement structure of an exhaust gas sensor and a motorcycle. Background technique [0002] In the exhaust system of a vehicle engine in accordance with current exhaust regulations, it is required to monitor the degradation state of a catalytic device for purifying exhaust gas. For example, in Patent Document 1, an oxygen sensor for detecting the oxygen concentration of exhaust gas is provided on the downstream side of the catalytic device. [0003] Specifically, in Patent Document 1, the interior of the muffler is partitioned by a plurality of partition walls (partition members) to form a plurality of expansion chambers. A catalytic device is arranged inside the muffler, and the downstream end of the catalytic device extends until it protrudes into a predetermined expansion chamber. In addition, each expansion chamber and catalytic device is connected to a plurality of exhaust pipes. The oxygen sensor is attached so a...

AI Technical Summary

Problems solved by technology

[0008] However, in Patent Document 1, a part of the outer wall of the muffler is recessed in order to arrange the oxygen sensor.

As a result, the volume of the expansion chamber becomes smaller in proportion to the amount of depression of the outer wall, and there is a possibility that the sound-absorbing effect of the exhaust gas may be reduced.

In addition, the temperature of the exhaust gas decreases as it goes downstream. Therefore, from the viewpoint of temperature activation of the catalytic device and the oxygen sensor, there is a possibility that the oxygen concentration of the exhaust gas cannot be detected appropriately while ensuring the exhaust gas purification performance.

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