EGR Pressure Reducing Device for High Differential Control
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Solution Overview
Problem
High pressure differentials across internal combustion engines during thermal management conditions make it difficult to control exhaust gas recirculation (EGR) flow, leading to increased NOx emissions as EGR flow is often terminated, which can result in higher NOx output.
Innovation Solution
A pressure reducing device within the EGR system, such as a Roots-type blower or turbine, is used to regulate EGR flow pressure by extracting work from the EGR flow, allowing the EGR valve to maintain control even under elevated exhaust manifold pressures, and can be connected to an electrical device to convert energy into electrical energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If exhaust throttle is closed or VGT inlet is over-closed to create back-pressure for thermal management, then SCR catalyst temperature is maintained in desired range, but EGR flow control becomes difficult due to high pressure differential
Solution Approach 1:
A pressure reducing device is introduced as an intermediary component in the EGR system to mediate between the high-pressure exhaust manifold and the EGR valve. This device reduces the pressure differential that the EGR valve must overcome, enabling proper EGR flow control while the exhaust throttle remains closed for thermal management of the SCR catalyst.
Solution Approach 2:
The EGR system is segmented into multiple functional components: the pressure reducing device that handles pressure differential reduction, and the EGR valve that handles flow control. This segmentation allows each component to perform its specific function effectively - the pressure reducing device manages the pressure issue while the EGR valve focuses on flow regulation.
2Reliability
If exhaust throttle is closed or VGT inlet is over-closed to create back-pressure, then thermal management of aftertreatment components is improved, but EGR flow is terminated due to lack of control
Solution Approach 1:
The pressure reducing device serves as a mediator that enables EGR flow to be maintained during thermal management conditions. By reducing the pressure differential upstream of the EGR valve, it ensures sufficient pressure differential across the valve itself, allowing EGR flow to continue even when the exhaust throttle is closed for thermal management.
Solution Approach 2:
The pressure reducing device changes the pressure parameter in the EGR system by reducing the pressure upstream of the EGR valve. This parameter change restores the pressure differential needed for EGR flow control and maintenance, allowing the system to achieve both thermal management and EGR flow objectives simultaneously.
3Ease of operation
If EGR flow is terminated due to high pressure differential, then EGR valve control is lost, but NOx output increases due to cooler intake flow
Solution Approach 1:
The pressure reducing device acts as an intermediary that restores EGR valve control by reducing the upstream pressure. This enables the EGR valve to properly regulate EGR flow, maintaining the cooler intake flow conditions necessary for reduced NOx emissions while restoring control capability to the EGR valve.
Solution Approach 2:
The controller receives feedback about pressure differential conditions and adjusts the operation of the pressure reducing device accordingly. This feedback mechanism ensures that the pressure reducing device operates to maintain EGR flow control, thereby preventing NOx emissions increases that would result from EGR flow termination.
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 solution enables the maintenance of EGR flow during high pressure differential conditions, improving NOx reduction and energy harvesting, thus enhancing the thermal management and emissions control of internal combustion engines.
Implementation Method 1
the pressure reducing device extracts work from the EGR flow to reduce the pressure in the EGR system
Implementation Method 2
the pressure reducing device is a turbine
Implementation Method 3
the pressure reducing device is connected to an electrical device, such as a motor and/or a generator, to convert the energy in the EGR flow to electrical energy
Data Source
AI summary
Systems, apparatus, and methods are disclosed that include an internal combustion engine having a plurality of cylinders and controlling a device to reduce the pressure in an exhaust gas recirculation loop in response to a pressure condition exceeding a threshold.