CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese Patent Application No. 2019-001568, filed Jan. 9, 2019, Japanese Patent Application No. 2019-036290, filed Feb. 28, 2019, Japanese Patent Application No. 2019-060300, filed on Mar. 27, 2019, and Japanese Patent Application No. 2019-174526, filed Sep. 25, 2019, the entire disclosures of which are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to an exhaust gas processing device.

BACKGROUND

JP2008-075458A discloses a configuration provided with an air-fuel ratio sensor for detecting oxygen concentration in exhaust gas that has passed through a catalytic converter in an exhaust passage in which the catalytic converter and a DPF (diesel particulate filter) are provided so as to be linearly arranged side by side.

SUMMARY

Incidentally, a conventional exhaust gas processing device arranged in the vicinity of an internal combustion engine is required to be small due to a limited space for an installation, while mounting a plurality of catalysts in order to comply with emission control regulations. In addition, the exhaust gas processing device needs to determine exhaust gas components that have passed through the catalyst with a high accuracy, and it has been difficult to configure the exhaust gas processing device so as to satisfy these requirements.

An object of the present invention is to propose a small exhaust gas processing device capable of determining exhaust gas components with high accuracy while mounting a plurality of catalysts.

According to an aspect of the present invention, an exhaust gas processing device includes: a first catalyst carrier configured to clean exhaust gas flowing along the first direction; a second catalyst carrier configured to clean the exhaust gas that has passed through the first catalyst carrier, the exhaust gas flowing along a second direction intersecting with the first direction; a case configured to accommodate the first catalyst carrier and the second catalyst carrier; and a sensor having a measuring portion for measuring the exhaust gas, the sensor being configured to determine the exhaust gas that has passed through the first catalyst carrier, wherein the measuring portion of the sensor is arranged in a region surrounded by a downstream-side end surface of the first catalyst carrier, an upstream-side end surface of the second catalyst carrier, and an inner wall surface of the case, the inner wall surface being configured to receive the exhaust gas that has passed through the first catalyst carrier, the region being on the second catalyst carrier side of a center of the first catalyst carrier.

In the above-described aspect, the measuring portion of the sensor is located in the region surrounded by the downstream-side end surface of the first catalyst carrier, the upstream-side end surface of the second catalyst carrier, and the inner wall surface of the case, that is the region on the second catalyst carrier side of the center of the first catalyst carrier. In the region where the measuring portion of the sensor is arranged, because the main flow of the flow of the exhaust gas directed from the first catalyst carrier to the second catalyst carrier is formed by allowing the exhaust gas that has passed through the first catalyst carrier to flow against the inner wall surface of the case, the flow rate of the exhaust gas becomes relatively high. Therefore, by arranging the first catalyst carrier and the second catalyst carrier such that the flowing direction of the exhaust gas flowing through the first catalyst carrier intersects with the flowing direction of the exhaust gas flowing through the second catalyst carrier, the reduction in size of the exhaust gas processing device is realized while sufficiently ensuring the cleaning function for the exhaust gas, and further, even with such a configuration, highly accurate detection of the exhaust gas can be achieved by the sensor determining the exhaust gas.

