Upstream Catalytic Converter Volume for Exhaust Gas Temperature Management
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Solution Overview
Problem
Existing exhaust gas aftertreatment systems for diesel engines, particularly lean-burn engines, face challenges in achieving effective pollutant conversion, especially with low exhaust gas temperatures and the need for cost-effective solutions that maintain effectiveness across varying engine operating states.
Innovation Solution
The exhaust gas aftertreatment system positions a catalytically active exhaust gas converter with a volume of at least 0.6 liters upstream of the turbocharger, utilizing an oxidation catalytic converter and potentially a particle separator, to enhance pollutant conversion of hydrocarbons, carbon monoxide, and nitrogen oxides, with turbulence-generating structures to improve reaction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a catalytic converter is arranged downstream behind the turbocharger, then the exhaust gas temperature is higher for better catalytic activity, but the conversion effectiveness is inadequate especially for lean-burn engines
Solution Approach 1:
The patent applies preliminary action by placing a catalytic converter upstream of the turbocharger to perform pollutant conversion before the exhaust gas reaches the turbocharger. This allows the catalytic converter to operate on exhaust gases that have not been cooled by the turbocharger, maintaining higher temperatures and improving conversion effectiveness especially for lean-burn engines.
Solution Approach 2:
The patent inverts the conventional arrangement by placing the catalytic converter upstream of the turbocharger instead of downstream. This inversion allows the catalytic converter to benefit from higher exhaust gas temperatures before the gas is cooled by the turbocharger, thereby improving pollutant conversion effectiveness.
2Stress or pressure
If a small catalytic converter is used upstream of the turbocharger to avoid excessive throttling, then the pressure drop is reduced, but the conversion effectiveness is inadequate
Solution Approach 1:
The patent applies parameter changes by optimizing the volume of the upstream catalytic converter to at least 0.6 liters, which is sufficiently large to achieve adequate pollutant conversion effectiveness while controlling the pressure drop. The specific volume parameter is optimized to balance conversion effectiveness with pressure loss.
3Productivity
If oxidation catalytic converters are used to remove hydrocarbons and carbon monoxide, then these pollutants are converted, but the low exhaust gas temperatures cause considerable difficulties in achieving effective conversion
Solution Approach 1:
The patent places the oxidation catalytic converter upstream of the turbocharger to perform oxidative conversion of hydrocarbons and carbon monoxide before the exhaust gas temperature is reduced by the turbocharger. This preliminary action ensures effective conversion occurs at higher temperatures.
Solution Approach 2:
The patent optimizes the volume parameter of the upstream catalytic converter to at least 0.6 liters, which provides sufficient catalytic surface area to achieve effective oxidation of hydrocarbons and carbon monoxide at the operating temperatures upstream of the turbocharger.
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 significantly increases pollutant conversion rates, particularly for hydrocarbons and carbon monoxide, while maintaining system effectiveness across different engine states and operating conditions, and is cost-effective by leveraging the higher temperatures near the engine for enhanced catalytic activity.
Implementation Method 1
The exhaust gas converter (6) provided between the internal combustion engine (2) and the at least one turbocharger (5) has a first volume (7) which is greater than a second volume (8) of the at least one exhaust gas aftertreatment unit (9) provided opposite the at least one turbocharger (5)
Implementation Method 2
a catalytically active exhaust gas converter with a volume of at least 0.6 liters upstream of the turbocharger, utilizing an oxidation catalytic converter
Data Source
Figure 1~2
AI summary
The invention relates to an exhaust-gas secondary treatment system (1) for an internal combustion engine (2) of a vehicle (3) having at least one exhaust pipe (4) and at least one turbocharger (5) and at least one exhaust converter (6), wherein the catalytic converter (6) is provided between the internal combustion engine (3) and the minimum of one turbocharger (5) that has an initial volume (7) of at least 0.6 liters.