Spark-Ignition Engine Particle Filter Regeneration via Lean Operation
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Solution Overview
Problem
Spark-ignition internal combustion engines face challenges in reducing nitrogen oxide emissions and regenerating particle filters due to insufficient oxygen levels and temperature conditions, especially in vehicles with frequent cold starts and short distances, which hinder effective exhaust gas aftertreatment and soot particle oxidation.
Innovation Solution
A method for operating a spark-ignition internal combustion engine with a particle filter involves increasing the filter temperature to a predefinable regeneration temperature and operating the engine superstoichiometrically to provide the necessary oxygen for filter regeneration, ensuring conditions for effective soot particle oxidation and filter cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the engine operates stoichiometrically with a three-way catalytic converter to reduce nitrogen oxide emissions, then nitrogen oxide reduction is improved, but oxygen availability for particle filter regeneration deteriorates
Solution Approach 1:
The exhaust aftertreatment system is segmented into functionally distinct components: a three-way catalytic converter for nitrogen oxide reduction and a separate particle filter for soot oxidation. This segmentation allows each component to operate under its optimal conditions independently, resolving the contradiction between nitrogen oxide reduction (requiring stoichiometric operation) and oxygen availability for particle filter regeneration.
2Quantity of substance
If the engine operates with high excess of air (lean mode) to provide oxygen for particle oxidation, then oxygen availability is improved, but nitrogen oxide reduction capability deteriorates
Solution Approach 1:
By separating the nitrogen oxide reduction function (handled by three-way catalytic converter during stoichiometric operation) from the particle oxidation function (handled by particle filter during lean operation), the system can provide oxygen for particle oxidation without compromising nitrogen oxide reduction capability.
Solution Approach 2:
The engine operates periodically alternating between stoichiometric mode (for nitrogen oxide reduction) and lean mode (for particle filter regeneration). This periodic switching allows both functions to be performed effectively over time, resolving the contradiction between oxygen availability and nitrogen oxide reduction capability.
3Productivity
If the engine operates with frequent cold starts and short distances, then productivity is improved, but particle filter regeneration capability deteriorates due to insufficient temperature
Solution Approach 1:
The system proactively monitors particle filter loading and proactively initiates regeneration operations before the filter becomes overloaded. By using control strategies that predict when regeneration is needed and preparing accordingly, the system ensures regeneration can occur even after cold starts when temperatures would otherwise be insufficient.
Solution Approach 2:
The system dynamically adjusts engine operating parameters (such as injection timing, EGR rate, and air-fuel ratio) to elevate exhaust gas temperature during regeneration phases. This dynamic adaptation allows the system to achieve necessary regeneration temperatures even in scenarios with frequent cold starts and short driving distances.
4Object-generated harmful factors
If a particle filter is added to the exhaust system for soot particle removal, then harmful emissions are reduced, but device complexity and oxygen requirement increase
Solution Approach 1:
The exhaust aftertreatment system is designed with multi-functionality: the three-way catalytic converter handles nitrogen oxide reduction and the particle filter handles soot oxidation. By integrating these functions into a coordinated system that shares common control and monitoring infrastructure, the overall complexity is managed while achieving multiple emission reduction goals simultaneously.
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 ensures the regeneration of the particle filter even under conditions where normal operation does not provide sufficient temperature and oxygen, maintaining compliance with stringent emission limits and preventing filter overload by initiating regeneration based on specific criteria such as filter loading and engine operation parameters.
Implementation Method 1
oxidation of the soot particles stored in the filter is to be initiated
Implementation Method 2
exhaust gas heating system (40) arranged in the at least one exhaust line (4)
Data Source
AI summary
Embodiments for regenerating a particle filter are provided. In one example, a method includes operating a spark-ignition internal combustion engine having a particle filter for collecting and burning soot particles in exhaust gas comprises in order to initiate regeneration of the particle filter. The method may include, in response to a regeneration condition, increasing exhaust temperature by retarding spark timing and once regeneration is reached, operating the engine with lean combustion to regenerate the particle filter, where a degree of leanness is based on each of a state of the filter and an upstream three-way catalyst.