Dedicated EGR Cylinder Bypass Valve Control
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Solution Overview
Problem
Internal combustion engines face inefficiencies in air-fuel mixture regulation and torque output, particularly when using dedicated exhaust gas recirculation (EGR), as existing systems struggle to optimize exhaust gas recirculation and air intake to achieve balanced engine performance.
Innovation Solution
The engine system incorporates a bypass valve, an EGR valve, and an air/EGR mixer to selectively direct exhaust gas back into the intake manifold, with a turbocharger and sensors to control the flow, ensuring optimal pressure and air-fuel mixture for improved torque output and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If exhaust gas is recirculated to the intake manifold, then engine efficiency is improved, but air-fuel mixture regulation becomes difficult to optimize
Solution Approach 1:
The system divides the engine into dedicated EGR cylinders and non-EGR cylinders, with separate exhaust flow paths. The bypass valve segments the exhaust flow to direct it either to the EGR valve or to the atmosphere, allowing independent control of EGR quantity and air-fuel mixture composition without interfering with overall engine performance optimization.
2Use of energy by moving object
If dedicated EGR is implemented, then engine efficiency improves, but torque output optimization becomes challenging
Solution Approach 1:
The system employs dynamic control of the bypass valve and EGR valve to adjust exhaust gas recirculation levels in real-time based on operating conditions. The bypass valve can open to atmosphere when high torque is needed, while the EGR valve recirculates exhaust when efficiency is prioritized, allowing the system to dynamically optimize between torque output and fuel efficiency.
3Stability of the object's composition
If exhaust is directed through EGR valve to intake manifold, then air-fuel mixture is stabilized, but system complexity increases
Solution Approach 1:
The bypass valve serves multiple functions: it directs exhaust to the EGR valve for recirculation, directs exhaust to atmosphere for high torque conditions, and works in conjunction with the EGR valve to control the quantity of recirculated exhaust. This multi-functionality reduces the need for additional dedicated components while maintaining stable air-fuel mixture composition.
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 enhances engine efficiency by stabilizing air-fuel mixture and minimizing engine noise, allowing for precise control of EGR and air intake, thereby optimizing torque output and reducing errors in mass airflow sensor measurements.
Implementation Method 1
the EGR valve, where the EGR valve is configured to, when open, enable flow of the exhaust to an intake manifold of the internal combustion engine
Implementation Method 2
an air/EGR mixer is configured to mix: the ambient air; and exhaust received from the EGR valve
Implementation Method 3
an EGR cooler is located between the bypass valve and the EGR valve and is configured to cool the exhaust flowing from the bypass valve to the EGR valve
Implementation Method 4
a turbine of a turbocharger is located downstream of the bypass valve
Data Source
AI summary
An engine system includes: an internal combustion engine having a plurality of cylinders; a bypass valve arranged to receive exhaust output from at least a dedicated one of the cylinders and to selectively one of: direct the exhaust through an exhaust system to atmosphere; and direct the exhaust to an exhaust gas recirculation (EGR) valve; the EGR valve, where the EGR valve is configured to, when open, enable flow of the exhaust to an intake manifold of the internal combustion engine; and an intake air valve located between an air cleaner and a mass airflow (MAF) sensor and configured to, when open, enable flow of ambient air to the intake manifold.