Lambda Probe Catalytic Converter for Rapid Exhaust Heating
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Solution Overview
Problem
Current exhaust gas aftertreatment systems in internal combustion engines face challenges in quickly heating up three-way catalytic converters during cold starts while minimizing emissions, especially due to limitations in existing secondary air systems and exhaust gas burners.
Innovation Solution
A device comprising an exhaust gas burner and a lambda probe catalytic converter configuration, where the lambda probe is positioned to detect oxygen storage capacity deviations, allowing for stoichiometric exhaust gas regulation and preventing rich or lean blow-outs, with a secondary air system and fuel injector for precise air-fuel ratio control, and a turbine for mixing burner exhaust gases with engine exhaust for efficient heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If secondary air is introduced into the exhaust gas system to heat up the three-way catalytic converter, then the heating speed is improved, but emissions increase due to rich blow-outs
Solution Approach 1:
A lambda probe is positioned downstream from the first catalyst volume and upstream from the second catalyst volume to detect the actual air-fuel ratio in real-time. This feedback signal is used by the control unit to adjust the secondary air injection and fuel injector operation, preventing rich blow-outs while maintaining rapid heating of the catalytic converter.
Solution Approach 2:
The system dynamically changes the air-fuel ratio parameters by controlling the fuel injector and secondary air injection based on lambda probe feedback. The lambda value is regulated to remain at or near 1 (stoichiometric), preventing the rich conditions that cause harmful emissions during the heating phase.
2Productivity
If an exhaust gas burner is used to heat the three-way catalytic converter, then heating efficiency is improved, but device complexity increases
Solution Approach 1:
The exhaust gas burner is integrated directly into the exhaust gas channel, merging the heating function with the existing exhaust system. The burner utilizes the existing exhaust gas flow and channel structure, avoiding the need for separate heating systems and reducing overall device complexity while maintaining high heating efficiency.
3Measurement precision
If the lambda probe is positioned upstream from the catalytic converter, then measurement response is improved, but regulation precision deteriorates due to oxygen storage capacity
Solution Approach 1:
The catalytic converter is divided into two distinct catalyst volumes: a first catalyst volume upstream of the lambda probe with lower oxygen storage capacity for rapid lambda detection and regulation response, and a second catalyst volume downstream with higher oxygen storage capacity for stabilizing the exhaust gas and preventing blow-outs. This segmentation allows each volume to perform its specific function optimally.
Solution Approach 2:
Different regions of the catalytic converter are assigned different oxygen storage capacities tailored to their specific functions. The upstream first catalyst volume has reduced oxygen storage capacity to enable quick lambda probe response and accurate regulation, while the downstream second catalyst volume has increased oxygen storage capacity to ensure stability and prevent emissions during transient 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 configuration enables rapid heating of the three-way catalytic converter during cold starts, minimizes emissions, and ensures efficient conversion of pollutants once the converter reaches operating temperature, while reducing the risk of lambda blow-outs and optimizing fuel efficiency.
Implementation Method 1
a hot burner exhaust gas is fed into the exhaust gas channel of the internal combustion engine upstream from a three-way catalytic converter in order to heat the three-way catalytic converter up to its operating temperature
Implementation Method 2
the lambda probe is arranged downstream from a first catalyst volume of the three-way catalytic converter and upstream from a second catalyst volume of the three-way catalytic converter
Implementation Method 3
a three-way catalytic converter is arranged in the exhaust gas system downstream from an outlet of the internal combustion engine
Data Source
AI summary
A device for exhaust gas aftertreatment in an internal combustion engine can be connected to an outlet of the internal combustion engine. The device comprises an exhaust gas system with an exhaust gas channel in which a three-way catalytic converter is arranged, and an exhaust gas burner with which hot burner exhaust gases can be fed into the exhaust gas channel at a feed point upstream from the three-way catalytic converter. The three-way catalytic converter is configured as a lambda probe catalytic converter and comprises a first catalyst volume and a second catalyst volume, whereby a lambda probe is arranged downstream from the first catalyst volume and upstream from the second catalyst volume, whereby the first catalyst volume has a lower oxygen storage capacity than the second catalyst volume. A method for exhaust gas aftertreatment in an internal combustion engine has such an exhaust gas aftertreatment device.