Reversible EGR Pump for Exhaust Leakage Control
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Solution Overview
Problem
Internal combustion engine systems face issues with exhaust gas recirculation (EGR) leakage through EGR pumps, leading to fouling and corrosion, particularly during exhaust thermal management (ETM) modes and low speed/low load operations, where recirculation is not desired.
Innovation Solution
A reversible EGR pump is implemented, capable of operating in forward and reverse modes, with a controller managing the pump's operation based on engine conditions to prevent exhaust gas leakage by either recirculating exhaust gas or providing a non-exhaust air flow in the reverse direction, thereby inhibiting contamination and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an EGR pump is used to control exhaust gas recirculation flow, then the ability to actively control EGR flow is improved, but exhaust gas leakage through the pump causes fouling and corrosion of components
Solution Approach 1:
The pump is operated in reverse mode to flow non-exhaust air through the EGR system, which prevents exhaust gas from leaking through the pump and causing fouling and corrosion. This reverse flow action directly counteracts the harmful leakage effect.
Solution Approach 2:
The potential harmful effect of exhaust gas leakage is converted into a beneficial reverse flow mechanism. By operating the pump in reverse, the system uses the pump's capability to create a protective air flow that prevents the harmful leakage, turning what could be a problematic feature into a protective function.
2Object-affected harmful factors
If exhaust gas recirculation is maintained during all engine operations, then NOx emissions are controlled, but system complexity increases to manage different operating modes
Solution Approach 1:
The EGR system dynamically adjusts its operation based on engine conditions. The controller monitors engine operating parameters and switches the pump between forward and reverse modes as needed, allowing the system to adapt to different operating conditions without requiring separate physical systems for each mode.
Solution Approach 2:
The single EGR pump serves multiple functions: it can operate in forward mode to recirculate exhaust gas for NOx control during normal operation, and in reverse mode to prevent fouling and corrosion during ETM and low speed/low load operations. This multi-functionality reduces the need for separate components for different operating modes.
3Object-affected harmful factors
If the EGR pump operates continuously in forward mode, then exhaust gas recirculation is maintained for emission control, but contamination and corrosion of EGR components occurs during modes where recirculation is not desired
Solution Approach 1:
The pump operates periodically in reverse mode during specific engine operating conditions (ETM and low speed/low load) to prevent contamination and corrosion. This periodic reverse operation is timed based on engine conditions, allowing the system to maintain component reliability while still achieving emission control during appropriate operating modes.
Solution Approach 2:
The controller monitors engine operating parameters and uses this feedback to determine when to switch the pump between forward and reverse modes. This feedback mechanism ensures the pump operates in reverse only when needed to protect components, while maintaining forward operation for emission control during appropriate 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
The reversible EGR pump effectively reduces contamination and corrosion of EGR system components by preventing exhaust gas leakage, enhancing the longevity and performance of the EGR system across various engine operating modes.
Implementation Method 1
an EGR cooler that cools exhaust gas flowing through the EGR system
Data Source
AI summary
An engine system includes an engine having piston-cylinder arrangements communicating with an intake manifold and an exhaust manifold, a turbocharger including a turbine in communication with the exhaust manifold and a compressor driven by the turbine and in communication with the intake manifold, and an EGR system including an EGR pump having an inlet side in communication with the exhaust manifold and an outlet side in communication with the intake manifold, and an EGR cooler that cools exhaust gas flowing through the EGR system. The engine system also includes a controller operably connected with the EGR pump and configured to selectively operate the EGR pump in a forward mode to flow exhaust gas therethrough in a first direction and in a reverse mode to substantially prevent flow of exhaust gas therethrough or provide a non-exhaust air flow therethrough in a second direction.