Variable Restriction EGR Manifold for Backpressure Reduction
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Solution Overview
Problem
Internal combustion engines face inefficiencies due to the need for higher exhaust manifold pressure than intake manifold pressure to facilitate exhaust gas recirculation (EGR), leading to increased backpressure and reduced engine efficiency, as well as complex control of EGR flow rates using variable geometry turbochargers.
Innovation Solution
An apparatus and method that include a variable restriction passage coupling the exhaust manifold to the EGR manifold, allowing for controlled EGR flow, using a two-way or one-way valve, and a variable geometry turbocharger to manage pressure differentials, with a controller module to determine and achieve EGR flow, intake air, and exhaust manifold pressure targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If exhaust manifold pressure is maintained higher than intake manifold pressure to facilitate EGR flow, then EGR flow is achieved, but engine efficiency deteriorates due to increased backpressure
Solution Approach 1:
The exhaust system is segmented into two separate manifolds: an exhaust manifold for collecting exhaust from power strokes and an EGR manifold for delivering exhaust to intake strokes. This segmentation allows independent pressure management, enabling EGR flow without requiring the entire exhaust system to operate at high backpressure, thus improving engine efficiency while maintaining EGR flow capability.
Solution Approach 2:
A variable geometry turbocharger (VGT) is introduced as an intermediary device between the exhaust manifold and EGR manifold. The VGT uses exhaust gas energy to drive a compressor that delivers pressurized air to the intake manifold, while simultaneously controlling EGR flow through its variable geometry mechanism. This intermediary approach eliminates the need for direct high backpressure in the exhaust manifold, reducing energy losses while maintaining effective EGR flow control.
2Ease of operation
If variable geometry turbocharger is used to control EGR flow rates, then EGR flow control is achieved, but device complexity increases due to dual control requirements
Solution Approach 1:
The variable geometry turbocharger is designed to perform multiple functions simultaneously: it controls EGR flow rates, manages intake air compression, and regulates exhaust manifold pressure. By making the VGT multi-functional, the system reduces the need for separate control devices for each parameter, thereby managing device complexity while achieving comprehensive control over EGR flow and engine operating 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
This solution enables efficient operation of internal combustion engines by optimizing pressure management within the engine, reducing backpressure losses and improving EGR flow control, thereby enhancing engine efficiency and meeting emissions regulations.
Implementation Method 1
a variable geometry turbocharger (VGT)
Implementation Method 2
One requirement for the flow of EGR is that exhaust gas pressures must be higher than inlet gas pressures, or the exhaust gas will not flow to the intake as desired
Data Source
AI summary
An apparatus, system, and method are disclosed for efficiently operating an engine utilizing exhaust gas recirculation (EGR). The apparatus includes an exhaust manifold receiving exhaust gas from a first cylinder set, an EGR manifold receiving exhaust gas from a second cylinder set, and a passage comprising a variable restriction. The passage fluidly couples the exhaust manifold to the EGR manifold. The apparatus further includes a controller with modules for interpreting engine operating conditions and controlling actuators in response to the engine operating conditions.