Regional Catalyst Cooling via Segmented Fuel Injection
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Solution Overview
Problem
Existing catalyst protection methods for internal combustion engines do not effectively account for the temperature distribution within the catalyst, leading to potential excessive heating and reduced purification capacity due to uniform fuel injection strategies.
Innovation Solution
A catalyst protection device that acquires bed temperature data for multiple regions in the exhaust gas flow direction and adjusts fuel injection amounts based on specific temperature requirements for each region, preventing excessive heating by optimizing fuel injection according to actual temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If uniform fuel injection increase is applied to the entire catalyst, then the catalyst temperature is reduced, but excessive fuel is injected in regions that do not require cooling, causing excessive rich state and deviation from stoichiometric air-fuel ratio
Solution Approach 1:
The catalyst is divided into multiple regions along the exhaust gas flow direction, with temperature monitored independently for each region. This segmentation allows selective fuel injection increase only in regions where temperature exceeds thresholds, preventing uniform over-injection throughout the entire catalyst.
Solution Approach 2:
Different regions of the catalyst are treated differently based on their local temperature conditions. The control system adjusts fuel injection amounts locally for each region rather than applying a uniform increase, ensuring that cooling is applied only where necessary while maintaining stoichiometric ratios in regions that do not require cooling.
2Temperature
If fuel injection amount is increased to cool the catalyst, then catalyst temperature decreases, but the air-fuel ratio deviates from stoichiometric condition, affecting purification efficiency
Solution Approach 1:
By segmenting the catalyst into multiple regions and monitoring temperatures independently, the system can apply cooling fuel injection only to specific overheated regions while maintaining stoichiometric air-fuel ratios in other regions, thus preserving overall purification efficiency.
Solution Approach 2:
The control system applies local quality control by adjusting fuel injection based on regional temperature conditions. This ensures that purification capacity is maintained by avoiding unnecessary fuel injection in regions that are already at appropriate temperatures, preventing deviation from stoichiometric conditions.
3Device complexity
If temperature distribution in exhaust gas flow direction is not considered, then control system is simple, but catalyst may partially enter excessive-temperature state reducing purification capacity
Solution Approach 1:
The catalyst is segmented into multiple regions along the exhaust flow direction, with independent temperature monitoring for each region. This segmentation enables the control system to detect and respond to localized temperature variations, ensuring reliable purification by preventing any region from entering excessive-temperature states.
Data Source
AI summary
A catalyst protection device includes: a catalyst provided in an exhaust system of an internal combustion engine; a bed temperature acquisition unit that acquires a bed temperature for each of a plurality of regions of the catalyst distributed in an exhaust gas flow direction; and a fuel injection unit that determines for each of the regions whether an increase in fuel injection amount is required on the basis of the corresponding bed temperature acquired by the bed temperature acquisition unit, that calculates an increase in fuel injection amount for each region and that injects fuel of an amount including the sum of the calculated increase values.