NSR Catalyst Controller Adjusting Reducing Agent for NOx Purge
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Solution Overview
Problem
The existing exhaust gas purification systems for internal combustion engines face challenges in managing NOx emissions due to variations in storage modes within NOx storage reduction catalysts, leading to potential deterioration in exhaust emissions, as the ease of NOx release and subsequent reduction can change based on temperature history and storage modes, affecting the amount of NOx purged during rich spike operations.
Innovation Solution
An exhaust gas purification apparatus is designed with a controller that adjusts the supply of reducing agents to a post-stage catalyst based on the temperature history and storage modes of the NOx storage reduction catalyst, ensuring optimal reduction of NOx purged during rich spike operations by calculating storage amounts and nitrate ratios, and controlling the supply of ammonia or fuel to maintain effective NOx reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If rich spike is carried out to reduce stored NOx in the NSR catalyst, then NOx reduction is achieved, but a part of stored NOx may be purged without being reduced, leading to potential exhaust emission deterioration
Solution Approach 1:
The controller monitors the temperature history of the NSR catalyst and uses this feedback information to determine the storage mode of NOx. Based on this feedback, the controller adjusts the reducing agent supply amount to the post-stage catalyst to ensure complete NOx reduction even when purging occurs during rich spike operations.
Solution Approach 2:
The controller预先 calculates the storage mode of NOx based on the temperature history of the NSR catalyst before rich spike operations. This preliminary determination allows the controller to pre-adjust the reducing agent supply amount to the post-stage catalyst, ensuring that sufficient reducing agent is available to handle potential NOx purging during the upcoming rich spike.
2Adaptability or versatility
If the storage mode of NOx varies due to temperature history, then the amount of NOx purged during rich spike changes, but existing control systems do not account for this variation, leading to inadequate NOx reduction control
Solution Approach 1:
The controller changes the control parameter (reducing agent supply amount) based on the temperature history parameter. By monitoring how the NSR catalyst temperature has varied over time, the controller determines the NOx storage mode and adjusts the reducing agent supply accordingly, enabling the system to adapt to different storage modes without complex additional hardware.
3Object-generated harmful factors
If reducing agent supply to post-stage catalyst is increased to handle NOx purging, then exhaust emissions are maintained, but reducing agent consumption increases
Solution Approach 1:
The controller applies partial action by adjusting the reducing agent supply amount based on the determined storage mode. Rather than always supplying maximum reducing agent, the controller calculates the appropriate amount needed based on temperature history and storage mode, providing just enough reducing agent to handle the expected NOx purging without excessive consumption.
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 approach effectively suppresses the deterioration of exhaust emissions by ensuring that the NOx purged from the NOx storage reduction catalyst is appropriately reduced, maintaining emission standards despite variations in storage modes and temperature conditions.
Implementation Method 1
The NSR catalyst has a function to store NOx in exhaust gas when the air fuel ratio of its ambient atmosphere is a lean air fuel ratio... the term 'storage' is used as such including a mode of 'adsorption'
Implementation Method 2
a post-stage catalyst that is arranged in the exhaust passage at the downstream side of the first NOx storage reduction catalyst, and reduces NOx in an exhaust gas by a supplied reducing agent
Implementation Method 3
reduces the NOx thus stored when the air fuel ratio of the ambient atmosphere is a rich air fuel ratio lower than the stoichiometric air fuel ratio and when a reducing agent exists
Data Source
AI summary
An exhaust gas purification apparatus for an internal combustion engine includes: a controller comprising at least one processor is configured to carry out rich spike; wherein the controller carries out supply control to supply a reducing agent to a post-stage catalyst, wherein in cases where a temperature of an NSR catalyst becomes less than a predetermined determination temperature in at least a part of a determination period of time, the controller carries out the supply control according to the execution of current rich spike; wherein the controller controls such that in cases where the storage amount of NOx is the same, an amount of supply of the reducing agent in the supply control is made larger as a period of time in which the temperature of the NSR catalyst becomes less than the predetermined determination temperature in the determination period of time becomes longer.