Multi-Stage EGR Cooler with Bypass for Soot Prevention
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Solution Overview
Problem
Existing exhaust gas recirculation systems for internal combustion engines lack sufficient adjustability in cooling capacity, particularly during low-load phases, leading to potential component sooting due to excessive cooling of recirculated exhaust gases.
Innovation Solution
An exhaust gas recirculation device with a multi-stage cooling system, including a first cooling stage and an additional cooling stage, a bypass line, and a three-position EGR valve, allowing for adjustable cooling capacity by routing exhaust gas through either the cooling stages or bypassing them, integrated within a compact housing design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the cooling capacity of the exhaust gas cooler is increased to improve nitrogen oxide reduction, then the emission of nitrogen oxides is reduced, but the temperature of recirculated exhaust gas becomes too low causing component sooting
Solution Approach 1:
The exhaust gas cooler is divided into multiple cooling stages (first cooling stage, second cooling stage, third cooling stage) with independently controllable flaps. This segmentation allows selective activation of cooling stages based on operating conditions, enabling precise control of exhaust gas temperature to prevent sooting while maintaining nitrogen oxide reduction.
Solution Approach 2:
The patent implements dynamic control of cooling capacity through flaps that can be adjusted based on engine load and operating conditions. The control unit selectively opens or closes flaps to regulate the cooling effect, adapting the system to varying operational requirements and preventing excessive cooling that would cause sooting.
2Device complexity
If a single-stage cooling system is used to simplify the device structure, then the device complexity is reduced, but the adjustability of cooling capacity is insufficient
Solution Approach 1:
The cooling system is segmented into multiple independently controllable stages with individual flaps for each stage. This allows the system to provide fine-grained control over cooling capacity while maintaining a relatively compact structure, resolving the contradiction between complexity and adaptability.
Solution Approach 2:
The multi-stage cooling system with selectively controllable flaps provides universal adaptability across different operating conditions. The same structural framework can deliver varying cooling capacities from minimal to maximum, making the system versatile for different engine loads and operational scenarios.
3Object-generated harmful factors
If the recirculated exhaust gas is cooled too much during low-load phases to reduce nitrogen oxides, then the nitrogen oxide content is reduced, but steam and unburned hydrocarbons condense out causing sooting
Solution Approach 1:
The control system dynamically adjusts the cooling capacity by selectively opening or closing flaps based on real-time operating conditions. During low-load phases, the system can reduce cooling capacity to maintain exhaust gas temperature above condensation points, preventing sooting while still achieving nitrogen oxide reduction through controlled recirculation.
Solution Approach 2:
The control unit receives feedback about engine operating conditions and adjusts the flap positions accordingly. This feedback mechanism ensures that cooling capacity is optimized for each operating phase, preventing condensation of steam and unburned hydrocarbons while maintaining effective nitrogen oxide reduction.
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
Enables precise control of cooling capacity, preventing sooting during low-load phases by maintaining exhaust gas temperature and ensuring efficient engine operation across varying load conditions.
Implementation Method 1
at least one exhaust gas cooler (5), through which a first flow path (6) for recirculation of exhaust gas runs
Implementation Method 2
at least one first cooling stage (8) and at least one additional cooling stage (9)
Implementation Method 3
through which a first flow path (6) for recirculation of exhaust gas runs
Data Source
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AI summary
The invention relates to an internal combustion engine (2) comprising an exhaust gas recirculation system for recirculating exhaust gases from the internal combustion engine into an intake region (4.2) of the internal combustion engine (2), the exhaust gas recirculation system comprising the following components: at least one exhaust gas cooler (5) through which a first flow path (6) for recirculating exhaust gas extends, comprising at least one first cooling stage (8) and at least one additional cooling stage (9), at least one flap arrangement (10) by means of which the at least one additional cooling stage (9) can be connected, a bypass line (11) through which a second flow path (7) for recirculating exhaust gas extends and by means of which the exhaust gas cooler (5) can be bypassed during the recirculation of exhaust gas, and an EGR valve (12) having at least three possible positions.