Exhaust Gas Sensor Placement in Nested Catalyst Carriers
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Solution Overview
Problem
Conventional exhaust gas processing devices face challenges in being compact while maintaining high accuracy in determining exhaust gas components and ensuring effective cleaning with multiple catalysts, due to limited space and the need for precise component detection.
Innovation Solution
The design incorporates a configuration with a first catalyst carrier, a second catalyst carrier, and a sensor placement that intersects the flow directions of exhaust gas, ensuring high flow rates and accurate detection by positioning the sensor in a region surrounded by the downstream end surface of the first catalyst carrier, the upstream end surface of the second catalyst carrier, and the inner wall surface of the case, allowing for efficient cleaning and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple catalysts are mounted to ensure effective cleaning, then cleaning function is improved, but device size increases
Solution Approach 1:
The patent transitions from a linear arrangement of catalysts to a three-dimensional configuration where the first catalyst carrier is positioned downstream of the second catalyst carrier in the exhaust gas flow direction. This spatial reconfiguration allows multiple catalysts to be mounted within a compact volume by utilizing the cross-sectional area and flow path geometry rather than extending only in the flow direction.
Solution Approach 2:
The exhaust gas processing device employs a nested structure where the first catalyst carrier is arranged within the space defined by the second catalyst carrier and the case walls. The first catalyst carrier's upstream end is positioned near the downstream end of the second catalyst carrier, creating a compact nested arrangement that maximizes catalyst capacity within limited device volume.
2Volume of moving object
If catalysts are arranged linearly side by side, then device size is reduced, but measurement precision of exhaust gas components deteriorates
Solution Approach 1:
The patent creates distinct local regions with different flow characteristics: a first flow path through the first catalyst carrier and a second flow path through the second catalyst carrier. The sensor is positioned to selectively measure exhaust gas from the first flow path, creating a localized measurement zone that ensures precise detection of exhaust gas components after the first catalyst treatment without interference from the second catalyst region.
Solution Approach 2:
The exhaust gas processing device is segmented into distinct functional zones: a first catalyst carrier region for initial exhaust gas treatment, a second catalyst carrier region for additional treatment, and a sensor measurement region positioned to detect exhaust gas specifically from the first flow path. This segmentation allows independent optimization of each zone for its specific function while maintaining compact overall device size.
3Measurement precision
If sensor is positioned to measure exhaust gas after first catalyst carrier, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The case structure serves multiple functions simultaneously: it contains the first and second catalyst carriers, defines the flow paths for both catalysts, provides structural support for the sensor mounting, and creates the geometric constraints that naturally position the sensor in the optimal measurement location. This multi-functionality reduces device complexity by eliminating the need for separate sensor mounting structures or complex positioning mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables a compact exhaust gas processing device with enhanced cleaning functionality and accurate detection of exhaust gas components, even in limited spaces, by optimizing flow rates and sensor placement.
Implementation Method 1
a first catalyst carrier configured to clean exhaust gas flowing along the first direction
Implementation Method 2
a second catalyst carrier configured to clean the exhaust gas that has passed through the first catalyst carrier
Data Source
AI summary
In an exhaust gas processing device, an air-fuel ratio sensor is provided such that a measuring portion is located in a region surrounded by a downstream-side end surface of a TWC, an upstream-side end surface of a GPF, and an inner wall surface of a case against which the exhaust gas G that has passed through the TWC flows, that is the region a region on the GPF side of the center of the TWC.