Electrically Heated Catalyst for Exhaust Filter Regeneration
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Solution Overview
Problem
Existing exhaust aftertreatment systems for gasoline engines struggle to regenerate particulate filters efficiently across all operating conditions, particularly at low temperatures and underfloor positions, leading to increased emissions and fuel consumption.
Innovation Solution
An exhaust aftertreatment system with an engine-adjacent three-way catalyst, a particulate filter, and a heating catalyst equipped with electric heating elements powered directly by the engine's generator, allowing for rapid heating of the particulate filter independent of battery charge, combined with secondary air injection to achieve optimal mixing and oxygen supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the particle filter is continuously used to trap exhaust particles, then the exhaust treatment effectiveness is improved, but the pressure differential across the filter increases and eventually causes particle discharge
Solution Approach 1:
The system implements periodic regeneration cycles where the particle filter is alternately used for trapping particles and then subjected to a burning process to remove accumulated soot. This periodic switching between filtration and regeneration modes prevents the pressure differential from reaching critical levels while maintaining continuous exhaust treatment effectiveness.
Solution Approach 2:
The system discards accumulated soot particles from the filter through controlled combustion during regeneration cycles. By actively removing the trapped particles that cause pressure buildup, the system recovers the filter's permeability and maintains low pressure differential without compromising the overall particle trapping performance.
2Reliability
If the particle filter accumulates soot to treat exhaust, then the exhaust purification is improved, but the filter requires periodic burning that interrupts normal operation
Solution Approach 1:
The system performs preliminary actions by continuously monitoring the pressure differential across the particle filter and initiating regeneration cycles before the filter becomes completely blocked. This proactive approach ensures that the filter is regenerated at optimal intervals, maintaining exhaust purification effectiveness while minimizing interruptions to normal filtration operation.
Solution Approach 2:
The system employs feedback control by continuously measuring the pressure differential across the particle filter and using this information to trigger regeneration cycles. This closed-loop control optimizes the timing of regeneration operations, ensuring they occur when necessary to maintain purification performance while minimizing disruption to continuous exhaust treatment.
3Stress or pressure
If the particle filter is regenerated by burning, then the pressure differential is reduced, but CO and HC emissions increase during the burning process
Solution Approach 1:
The system introduces pure oxygen into the combustion chamber during regeneration to accelerate and complete the oxidation of soot particles. This strong oxidizing environment ensures thorough combustion of accumulated soot, converting it to CO2 rather than allowing incomplete combustion that would produce harmful CO and HC emissions, while effectively reducing the pressure differential.
Solution Approach 2:
The system creates a controlled combustion environment during regeneration that minimizes the formation of harmful emissions. By controlling the combustion conditions and using oxygen enrichment, the system promotes complete combustion of soot particles, reducing the generation of CO and unburned hydrocarbons that would otherwise be emitted during the burning process.
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
Enables efficient particulate filter regeneration in all operating situations, reducing emissions, fuel consumption, and extending regeneration intervals while maintaining engine performance and avoiding battery load.
Implementation Method 1
an exhaust flow is introduced into a particle filter and the exhaust particles are trapped on the particle filter
Implementation Method 2
the particle filter is regenerated by burning
Implementation Method 3
introducing oxygen into a combustion chamber and igniting the oxygen to thereby produce a burning oxygen flow
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to an exhaust aftertreatment system for an internal combustion engine (10). The exhaust aftertreatment system comprises an exhaust system (20) with at least one close-coupled three-way catalytic converter (22, 24), wherein a particulate filter (28) is arranged downstream of the three-way catalytic converter, preferably in the underbody position of a motor vehicle. Downstream of the at least one three-way catalytic converter (22, 24) and upstream of the particulate filter (28) a heating catalyst (26) is provided, which has at least one heating stage (62, 66, 68) that can be heated by means of an electric heating element (72, 74, 76, 78). It is provided that the at least one electrically heated heating stage (62, 66, 68) is supplied with electricity directly from a generator (46) which is in operative connection with the combustion engine (10), so that heating of the heating catalyst (26) takes place essentially independently of the state of charge of a vehicle battery (44).The invention further relates to a method for regenerating a particulate filter (28) in the exhaust system (20) of an internal combustion engine (10) by means of such an exhaust aftertreatment system.