Exhaust Gas Guide Structure for Sensor Responsiveness
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Solution Overview
Problem
Existing exhaust gas purification systems with NOx occlusion reduction type catalysts face inefficiencies due to delayed air/fuel ratio control and excessive fuel consumption, as oxygen concentration sensors are often poorly positioned, leading to incomplete NOx reduction and release of unused reducing agents like HC and CO.
Innovation Solution
A guide structure is implemented to direct exhaust gas flow to an oxygen concentration sensor installed between NOx purification and oxidation catalyst units within a single container, enhancing sensor responsiveness and optimizing air/fuel ratio control by positioning the sensor closer to the mainstream exhaust gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the oxygen concentration sensor is installed in the conventional position away from the mainstream exhaust gas flow, then the sensor structure is simpler and easier to install, but the sensor responsiveness is delayed and control accuracy is reduced
Solution Approach 1:
A guide structure acts as an intermediary component between the exhaust gas flow and the oxygen concentration sensor. This guide structure includes a guide plate or guide channel that redirects the exhaust gas flow to directly contact the sensor, enabling the sensor to detect exhaust gas composition accurately without being positioned in the mainstream flow path. The guide structure thus mediates between the conflicting requirements of sensor protection and measurement accuracy.
2Speed
If the oxygen concentration sensor is positioned to directly contact the mainstream exhaust gas flow, then the sensor responsiveness is improved, but the sensor may be damaged by high temperature and the structure becomes more complex
Solution Approach 1:
The guide structure serves as a protective intermediary that allows exhaust gas to contact the sensor without exposing the sensor directly to the harsh mainstream environment. The guide plate or channel creates a controlled interaction zone where exhaust gas can be sampled for detection while the sensor remains protected from direct exposure to high-temperature and high-velocity exhaust conditions.
Solution Approach 2:
The guide structure creates a localized detection zone with different flow characteristics from the mainstream exhaust. In this local region, the exhaust gas is redirected to contact the sensor at reduced velocity and temperature, while the rest of the exhaust flow continues along its original path. This local modification of flow quality enables both fast response and sensor protection.
3Use of energy by moving object
If air/fuel ratio control is delayed due to slow sensor response, then the system is simpler to control, but fuel consumption increases and reducing agents are wasted
Solution Approach 1:
The improved sensor responsiveness enabled by the guide structure provides timely feedback on the exhaust gas oxygen concentration and air/fuel ratio conditions. This rapid feedback allows the control system to make real-time adjustments to the air/fuel mixture, optimizing combustion efficiency and preventing waste of reducing agents. The guide structure thus enables an effective feedback control loop by ensuring accurate and timely sensor measurements.
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 improves the accuracy and speed of control mechanisms, limiting the supply of reducing agents to the minimum necessary, enhancing fuel efficiency and preventing the escape of unused HC and CO, while ensuring complete NOx reduction.
Implementation Method 1
A guide structure is implemented to direct exhaust gas flow to an oxygen concentration sensor installed between NOx purification and oxidation catalyst units
Implementation Method 2
enhancing sensor responsiveness and optimizing air/fuel ratio control by positioning the sensor closer to the mainstream exhaust gas flow
Implementation Method 3
the nitrogen dioxide will be reduced and purified by the oxidizing functions of the carrying noble metal 32. More specifically, the nitrogen dioxide will be reduced into water (H2O), carbon dioxide (CO2), and nitrogen gas (N2)
Implementation Method 4
the substances used as reducing agents from escaping, such as HC, from being released unused into the atmosphere, while at the same time completely reducing the NOx released by the rich control
Data Source
AI summary
Structure for guiding exhaust gas flow to an exhaust gas sensor in exhaust gas purification device installed in an exhaust passage, wherein a plurality of exhaust gas purification units is disposed in series in a container, the exhaust gas sensor is installed between the exhaust gas purification units and guide plates/pipes direct the exhaust gas flowing to the sensor to increase the exhaust gas sensor's responsiveness.