Dynamic Lambda Control for Exhaust Aftertreatment
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Solution Overview
Problem
Current exhaust gas aftertreatment systems for internal combustion engines face challenges in achieving optimal emission control due to rigid control systems that do not account for the unique characteristics of various exhaust gas aftertreatment components, leading to suboptimal emission results, especially under real driving conditions and varying operational conditions.
Innovation Solution
An exhaust gas aftertreatment system with a three-way catalytic converter and an electrically heatable catalytic converter, along with three lambda sensors, is used to dynamically adjust lambda control based on component temperature and operational readiness, ensuring optimal conversion performance and minimizing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a rigid lambda control system is used, then the control system is simple, but the emission conversion efficiency is suboptimal
Solution Approach 1:
The patent implements a dynamic lambda control system that adapts to varying operating conditions and catalyst temperatures. The control system continuously adjusts the lambda value based on real-time temperature sensors and emission data, transitioning from a rigid fixed-value control to a dynamic adaptive control that optimizes emission conversion efficiency across different operating scenarios.
Solution Approach 2:
The system changes the lambda control parameter dynamically based on catalyst temperature and emission conversion efficiency. When the catalyst reaches optimal temperature, the system adjusts lambda to maximize conversion efficiency. This parameter adaptation allows the system to maintain high emission conversion efficiency across varying operating conditions while managing control complexity through rule-based transitions.
2Productivity
If multiple exhaust aftertreatment components are added, then the emission conversion efficiency is improved, but the device complexity increases
Solution Approach 1:
The exhaust aftertreatment system is segmented into multiple functional components: a first catalytic converter for initial emission conversion, a second catalytic converter for enhanced conversion, and a particulate filter for soot removal. Each component handles specific emission types and operates at optimized temperatures, allowing the system to achieve high overall emission conversion efficiency while managing complexity through functional specialization.
Solution Approach 2:
The exhaust system integrates multiple functions into a unified aftertreatment architecture that handles both gas-phase emissions conversion and particulate matter removal. The catalysts are designed to perform multiple conversion functions (oxidation, reduction) while the particulate filter integrates with the catalytic converters to provide comprehensive emission control, achieving multi-functionality that improves overall system efficiency.
3Productivity
If the catalyst is heated quickly to light-off temperature, then the emission conversion efficiency is improved, but the energy consumption increases
Solution Approach 1:
The system performs preliminary heating of the catalytic converters during cold start conditions using electric heating elements before the engine reaches steady-state operating temperature. This preliminary action ensures the catalyst reaches light-off temperature quickly to maximize emission conversion efficiency during critical cold start periods, while the energy consumption is limited to only the heating phase and not continuous operation.
Solution Approach 2:
The catalytic converters are designed to be self-heating during normal engine operation, utilizing the exhaust gas temperature to maintain catalyst temperature above light-off point. This self-service mechanism eliminates the need for continuous external heating, reducing energy consumption while maintaining high emission conversion efficiency during steady-state and hot start conditions.
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 system enhances the efficiency of exhaust gas aftertreatment by quickly reaching light-off temperatures, maintaining catalyst activity, and adapting to special operating situations like particle filter regeneration, thereby reducing tailpipe emissions and secondary emissions.
Implementation Method 1
a first three-way catalyst is arranged in the exhaust system in the flow direction of an exhaust gas from the internal combustion engine
Implementation Method 2
an electrically heatable catalyst is arranged downstream of the first three-way catalyst
Implementation Method 3
three lambda probes are arranged in the exhaust system
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an exhaust gas aftertreatment system for an internal combustion engine. The exhaust gas aftertreatment system comprises an engine control device (50) and an exhaust gas system (20), in which, in the flow direction of an exhaust gas through an exhaust gas channel (22) of the exhaust gas system (20), a first catalytic converter (28), and, downstream of the first catalytic converter (28), an electrically heatable catalytic converter (30, 34) are arranged. At least three lambda probes (38, 40, 42) are arranged on the exhaust gas channel (22), wherein control of the combustion air ratio of the internal combustion engine (10) is carried out by means of natural frequency control. The lambda control of the internal combustion engine (10) is controlled by the lambda probe (38, 40, 42) upstream of the last 3-way catalytic converter (28, 30, 56), which has reached the light-off temperature thereof (TLOK1, TLOK2, TLOK3).