Exhaust Gas Heating Device for Catalytic Converter Light-Off
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Solution Overview
Problem
Existing exhaust gas systems for internal combustion engines face challenges in reducing pollutant emissions, particularly during cold starting, due to inefficiencies in hydrocarbon adsorption and catalytic conversion, leading to increased thermal mass, longer cold start phases, and higher costs.
Innovation Solution
The method involves using an adsorber and a catalytic converter with a heating device placed between them, operated based on the aging state of the catalytic converter, to optimize hydrocarbon conversion by adjusting the heat output and limiting temperature, ensuring efficient conversion of unburned hydrocarbons before they enter the environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the volume of the adsorber is enlarged to increase hydrocarbon storage capacity, then the amount of hydrocarbons stored in the adsorber increases, but the catalytic converter reaches the light-off temperature later due to increased thermal mass
Solution Approach 1:
The heating device is activated before the catalytic converter reaches its light-off temperature to preheat the system. This preliminary heating action ensures that when hydrocarbons are stored in the adsorber, the catalytic converter is already at or near the required temperature for immediate conversion, thus reducing the cold starting phase duration while maintaining adequate hydrocarbon storage capacity
Solution Approach 2:
The heating device changes the temperature parameter of the exhaust gas flow between the adsorber and catalytic converter. By actively controlling the temperature in this intermediate zone, the system can maintain optimal hydrocarbon storage in the adsorber while ensuring the catalytic converter reaches light-off temperature quickly, resolving the contradiction between storage capacity and activation time
2Reliability
If the exhaust gas system is over-dimensioned for safety reasons, then deviations in actual temperatures and coating quality are accommodated, but the thermal mass increases and the cold starting phase is lengthened
Solution Approach 1:
The heating device uses the exhaust gas itself as the heating medium, allowing the system to self-heat without external energy sources. The exhaust gas flow provides the necessary thermal energy to bring the catalytic converter to light-off temperature, eliminating the need for over-dimensioning while maintaining reliability through active temperature control
Solution Approach 2:
The heating device performs preliminary heating of the exhaust gas and catalytic converter before the main conversion process begins. This advance preparation ensures that the system is ready for immediate efficient operation, accommodating temperature variations and coating quality deviations without requiring excessive thermal mass
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 minimizes unburned hydrocarbons released into the environment, allows for efficient operation over the vehicle's service life, and reduces energy consumption, thereby enhancing pollutant control and system efficiency while lowering costs.
Implementation Method 1
The adsorber is used to adsorb hydrocarbons, but that adsorption is possible only up to a particular temperature (about 150° C.)
Implementation Method 2
at least one heating device disposed between the adsorber and the catalytic converter
Implementation Method 3
The hydrocarbons emerging from the combustion chamber of the internal combustion engine without being burned and/or the hydrocarbons desorbed by the adsorber are then supposed to be converted by using a substance with an oxidizing action in the catalytic converter
Implementation Method 4
converted by using a substance with an oxidizing action in the catalytic converter disposed downstream of the adsorber
Data Source
AI summary
A method for operating an exhaust gas system of an internal combustion engine having at least one adsorber for the adsorption of hydrocarbons, a catalytic converter disposed downstream of the adsorber for converting hydrocarbons and at least one heating device disposed between the adsorber and the catalytic converter, includes adapting operation of the heating device in dependence on a state of aging of the catalytic converter. A method for operating a motor vehicle and a motor vehicle having the system are also provided.