Engine Controller Cooling Valve Temperature During Sulfur Desorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing NOx storage reduction type catalysts in internal combustion engines face challenges with sulfur poisoning, leading to decreased NOx storage capacity and the risk of thermal damage to addition valves during desorption processes, while cooling fuel addition can cause HC slip if not managed properly.
Innovation Solution
A controller system that alternately repeats desorption and pausing processes for sulfur compound reduction, with cooling fuel addition only during the pausing process to prevent excessive temperature and thermal damage, using a target temperature calculation and addition amount calculation to ensure the addition valve's temperature does not exceed a predetermined limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling fuel addition is executed during the desorption process, then the temperature of the addition valve is reduced, but the air-fuel ratio becomes excessively rich causing HC slip
Solution Approach 1:
The cooling fuel addition is executed periodically only during the pausing process of the poison release control, not continuously during the desorption process. This periodic timing ensures the addition valve is cooled when needed while preventing excessive fuel addition that would cause HC slip during the desorption phase.
Solution Approach 2:
The cooling fuel addition is performed in advance during the pausing process before the desorption process begins. This preliminary cooling action ensures the addition valve temperature is reduced beforehand, preventing thermal damage during the subsequent desorption process without interfering with the desorption chemistry.
2Object-generated harmful factors
If cooling fuel addition is not executed during the desorption process, then HC slip is avoided, but the addition valve temperature increases causing thermal damage
Solution Approach 1:
The cooling fuel addition is performed in advance during the pausing process before the desorption process begins. This preliminary cooling action ensures the addition valve temperature is reduced beforehand, preventing thermal damage during the subsequent desorption process without interfering with the desorption chemistry.
Solution Approach 2:
The cooling fuel addition is executed periodically only during the pausing process of the poison release control, not continuously during the desorption process. This periodic timing ensures the addition valve is cooled when needed while preventing excessive fuel addition that would cause HC slip during the desorption phase.
3Productivity
If fuel is supplied from the direct injection valve during desorption process, then sulfur compound is desorbed from the catalyst, but the temperature of the addition valve increases excessively
Solution Approach 1:
The cooling fuel addition is executed periodically only during the pausing process of the poison release control, not continuously during the desorption process. This periodic timing ensures the addition valve is cooled when needed while preventing excessive fuel addition that would cause HC slip during the desorption phase.
Solution Approach 2:
The cooling fuel addition is performed in advance during the pausing process before the desorption process begins. This preliminary cooling action ensures the addition valve temperature is reduced beforehand, preventing thermal damage during the subsequent desorption process without interfering with the desorption chemistry.
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 HC slip and reduces thermal damage to the addition valve by controlling the cooling fuel addition during the pausing process, maintaining efficient NOx reduction while preventing excessive temperature increases.
Implementation Method 1
a direct injection valve 11, which is configured to directly inject fuel into a cylinder
Implementation Method 2
a desorption process of desorbing the sulfur compound deposited on the catalyst by performing a fuel supply from the direct injection valve to the exhaust gas in a state in which a temperature of the catalyst is increased to a desorbable temperature
Implementation Method 3
it is preferable to execute the cooling fuel addition, in which fuel is injected from the addition valve to cool the addition valve
Implementation Method 4
exhaust gas flowing into the catalyst
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A controller (80) alternately repeats a desorption process of desorbing sulfur compound deposited on an NSR catalyst (20) by supplying fuel from a direct injection valve (11) to exhaust gas, and a pausing process of pausing fuel supply from the injection valve (11) to the exhaust gas. The controller executes a cooling fuel addition for adding engine fuel from the addition valve of the exhaust passage to cool the addition valve during execution of the pausing process, and prohibit the cooling fuel addition during execution of the desorption process. The controller calculates a target temperature (Td) of the addition valve (35) at the time of start of the desorption process such that the temperature of the addition valve (35) during execution of the desorption process does not exceed an allowable upper limit temperature (Tc) and calculates the addition amount (CA) at the time of cooling fuel addition.