Exhaust Gas Cleaning System Flushing via Dedicated Device
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Solution Overview
Problem
The existing methods for flushing catalytic converters in exhaust gas cleaning systems of internal combustion engines do not adequately address the risk of overheating and unwanted oxidation during engine shutdown and false start attempts, leading to potential damage to the catalytic converter.
Innovation Solution
The method involves flushing the exhaust gas cleaning system in a passive operating phase using a separately driven flushing device, which determines and responds to the temperature of the catalyst bed to remove combustible fuel-air mixtures and cool the system independently of the engine's operating state, ensuring the catalytic converter is safe from ignition risks before restarting the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the exhaust gas cleaning system is flushed during active operating phase, then the system can be cooled down, but the internal combustion engine is unnecessarily cooled and the flushing cannot be performed when the engine is shut down
Solution Approach 1:
The patent separates the flushing function from the engine's exhaust gas flow by introducing a dedicated flushing device with its own drive mechanism. This segmentation allows the exhaust gas cleaning system to be flushed independently during passive operating phases without affecting engine operation or cooling requirements.
Solution Approach 2:
The patent implements flushing during passive operating phases before the engine is restarted after shutdown or false start attempts. This preliminary action removes combustible fuel-air mixtures and cools the catalyst bed in advance, preventing unwanted oxidation and deflagration risks during subsequent engine startup.
2Adaptability or versatility
If a separately driven flushing device is used, then the exhaust gas cleaning system can be flushed independently during passive operating phase, but the device complexity increases
Solution Approach 1:
The flushing device is designed to perform multiple functions: it can operate during both active and passive operating phases, and can control gas flow through the exhaust gas cleaning system independently of engine state. This multi-functionality justifies the added complexity by providing versatile operation capabilities.
3Temperature
If flushing is performed continuously, then the catalyst bed remains cool, but energy consumption increases and the engine cannot be operated efficiently
Solution Approach 1:
The patent implements periodic flushing operations during passive operating phases rather than continuous flushing. The flushing device operates intermittently based on engine operation cycles, cooling the catalyst bed only when the engine is shut down or not producing exhaust gas, thereby avoiding continuous energy consumption while maintaining temperature control.
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 enhances the reliability of engine startups by preventing overheating and oxidation damage, allowing for safe engine reactivation without cooling the internal combustion engine unnecessarily and ensuring no combustible mixtures are present in the exhaust tract.
Implementation Method 1
The exhaust gas cleaning system can be flushed independently of the operating state of the internal combustion engine... a separately driven flushing device... can be implemented, for example, by an electric motor
Implementation Method 2
the exhaust gas temperature downstream of an exhaust gas turbine of a turbocharger can rise to more than 400°C. This increase in the exhaust gas temperature leads to heating of a catalytic converter
Implementation Method 3
Depending on the temperature of the catalyst bed of the catalytic converter and the number of unsuccessful start attempts in series, undesirable oxidation of the fuel gas can occur
Data Source
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AI summary
The invention relates to a method for flushing an exhaust-gas cleaning system (3) of an internal combustion engine (4), which exhaust-gas cleaning system comprises a catalytic converter (1) having at least one catalyst bed (2), wherein an exhaust gas of the internal combustion engine (4) is fed to the exhaust-gas cleaning system (3) in an active operating phase of the exhaust-gas cleaning system (3) and no exhaust gas is fed to the exhaust-gas cleaning system (3) in a passive operating phase of the exhaust-gas cleaning system (3), wherein a temperature (T) of the at least one catalyst bed (2) is determined and the flushing occurs according to the determined temperature (T), wherein the exhaust-gas cleaning system (3) is flushed in the passive operating phase of the exhaust-gas cleaning system (3) by means of a flushing device (6), which is connected directly to an exhaust-gas line (5).