Boost Leakage Valve for Oxidation Catalyst Regeneration
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Solution Overview
Problem
Internal combustion engines face challenges in maintaining optimal exhaust temperatures during idling conditions, especially in cold environments, leading to incomplete combustion and accumulation of unburned hydrocarbons on oxidation catalysts, which can result in reduced emissions treatment efficiency and potential catalyst degradation.
Innovation Solution
A regeneration control system that includes a temperature sensor and an electrically actuated boost leakage valve, which increases the air-fuel ratio by selectively leaking boost, thereby raising the exhaust temperature to the regeneration temperature for accumulated hydrocarbons on the oxidation catalyst, ensuring effective catalyst regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If engine speed is increased during extended periods of idling to produce elevated exhaust temperatures, then exhaust temperature increases to enable catalyst regeneration, but fuel consumption increases
Solution Approach 1:
The system changes the air-fuel ratio parameter by leaking boost air into the intake manifold, creating a richer mixture that burns hotter and raises exhaust temperature without increasing engine speed or fuel injection quantity
Solution Approach 2:
The boost leakage valve acts as an intermediary device that introduces additional air into the combustion process, enabling temperature elevation through modified combustion chemistry rather than direct mechanical intervention
2Reliability
If engine speed is increased during extended periods of idling to produce elevated exhaust temperatures, then catalyst regeneration is enabled, but engine operational efficiency decreases
Solution Approach 1:
The system modifies the air-fuel ratio parameter through boost leakage to achieve the temperature conditions necessary for catalyst regeneration while maintaining the engine at idle speed, thus preserving operational efficiency
3Ease of operation
If conventional engine designs and operating strategies are used during cold idling conditions, then engine operation is simplified, but combustion completeness is reduced leading to hydrocarbon accumulation on the catalyst
Solution Approach 1:
The boost leakage valve serves as an intermediary that introduces additional air to enhance combustion completeness during cold idle conditions, preventing hydrocarbon accumulation without complicating engine operation
Solution Approach 2:
The system changes the air-fuel ratio during cold idle conditions through controlled boost leakage, improving combustion completeness and preventing harmful hydrocarbon accumulation on the catalyst
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 solution effectively increases exhaust temperatures to the regeneration point, ensuring optimal oxidation of unburned hydrocarbons, preventing catalyst degradation and maintaining emissions treatment efficiency without excessive fuel consumption.
Implementation Method 1
increase an exhaust temperature of the internal combustion engine to the regeneration temperature, based on an increased air-fuel ratio (AFR) produced in response to the commanded adjustment to the position of the electrically actuated boost leakage valve
Data Source
AI summary
A regeneration control system for an oxidation catalyst in an internal combustion engine includes a temperature sensor to produce a temperature signal indicative of an exhaust inlet temperature that is below a regeneration temperature for accumulated hydrocarbons on the oxidation catalyst, an electrically actuated boost leakage valve, and a regeneration control unit. The regeneration control unit commands an adjustment to the position of the electrically actuated boost leakage valve to increase leaked boost to increase exhaust temperature to the regeneration temperature by way of increased air-fuel ratio. Related methodology is disclosed.