Exhaust Purification System Catalyst Temperature Control
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Solution Overview
Problem
The existing exhaust purification systems face challenges in effectively diagnosing abnormal operations during the catalyst regeneration process, particularly due to excessive fuel injection leading to increased heat values within the catalyst, which can cause melting damage.
Innovation Solution
An exhaust purification system and method that employs a combination of feedback and feedforward controls to manage fuel injection and air-fuel ratios, utilizing sensors and modules within the ECU to adjust catalyst temperatures and injection amounts, enabling precise control during SOx purging and regeneration processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fuel injection amount is increased to restore NOx purification capacity by raising catalyst temperature, then SOx desorption is promoted, but excessive fuel injection causes heat value increase leading to catalyst melting damage
Solution Approach 1:
The system uses feedback control by comparing actual catalyst temperature with target temperature to dynamically adjust fuel injection amount. The ECU calculates temperature deviation and modifies injection quantity in real-time, preventing excessive temperature rise while ensuring effective SOx desorption. This closed-loop control resolves the contradiction by automatically balancing temperature elevation needs against melting damage risks.
Solution Approach 2:
The system performs preliminary diagnosis to detect abnormal operations before they cause catalyst damage. By monitoring fuel injection amounts and predicting heat value increases, the system takes preventive action to stop or reduce fuel injection when abnormal conditions are detected, avoiding catalyst melting damage before it occurs.
2Manufacturing precision
If fuel injection is controlled precisely during regeneration, then catalyst temperature control is improved, but system complexity increases due to multiple sensors and control modules
Solution Approach 1:
The ECU performs multiple functions including temperature estimation, abnormal operation diagnosis, and fuel injection control using integrated processing. The system reuses existing sensors (exhaust temperature sensors, airflow sensors) for multiple purposes, reducing the need for additional dedicated components while maintaining precise temperature control capability.
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
Effectively diagnoses and prevents abnormal operations during catalyst regeneration, reducing the risk of melting damage and optimizing fuel efficiency by maintaining precise temperature control and injection management.
Implementation Method 1
the oxidation catalyst 31, a NOx storage reduction catalyst 32 sequentially from an upstream side of an exhaust gas flow... the oxidation catalyst 31 oxidizes the unburned fuel to increase the temperature of exhaust gases
Implementation Method 2
The NOx storage reduction catalyst adsorbs NOx included in exhaust gases... the NOx storage reduction catalyst also adsorbs sulfur oxides (hereinafter, referred to as SOx) contained in exhaust gases
Implementation Method 3
when the exhaust gases are in a rich atmosphere, the NOx storage reduction catalyst reduces and purifies the adsorbed NOx with hydrocarbons contained in the exhaust gases into harmless gas for discharge
Data Source
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AI summary
An exhaust purification system includes: a NOx reduction catalyst 32 for reducing and purifying NOx in an exhaust gas; a catalyst regeneration control module 60 for executing a catalyst regeneration process of restoring a NOx purification capacity of the NOx reduction catalyst 32 by switching an air-fuel ratio of the exhaust gas from a lean state to a rich state by using in parallel an air system control to reduce an intake air amount and an injection system control to increase a fuel injection amount; an exhaust gas temperature sensor 43 that is provided on a downstream side of the NOx reduction catalyst 32 on an exhaust passageway 13; a catalyst temperature estimating module 78 for estimating a catalyst temperature of the NOx reduction catalyst 32 based on an operating state of an internal combustion engine 10; a temperature sensor value estimating module 81 for estimating a sensor value of the exhaust gas temperature sensor 43 based on the catalyst temperature that is inputted from the catalyst temperature estimating module 78; and an abnormality determination module 82 for determining on an abnormality of a catalyst regeneration process based on a difference in temperature between an actual sensor value and the estimated sensor value in the midst of execution of the catalyst regeneration process.