EGR Valve Control for Transient Engine Response
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Solution Overview
Problem
Conventional exhaust gas recirculation (EGR) systems experience delays in EGR flow rates during transient engine operation cycles, leading to inefficiencies in fuel consumption and potential engine misfires due to mismatched EGR and residual gas concentrations.
Innovation Solution
A control system and method that calculates a modified desired EGR mass flow rate by combining the predetermined desired EGR flow rate with the rate of change of EGR mass, using an EGR transient coefficient to adjust the EGR control valve position, ensuring the actual EGR flow rate closely matches the desired rate during transient cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional EGR control systems use a simple feedback loop based on desired EGR flow rate, then the system structure remains simple, but the actual EGR flow rate cannot respond quickly during transient engine operation, causing delays and mismatches with desired flow rates
Solution Approach 1:
The control system calculates the rate of change of EGR mass and uses this information proactively to adjust the EGR valve position before the actual EGR flow rate deviates significantly from the desired rate. This preliminary action based on derivative information allows the system to anticipate and compensate for delays in the EGR flow response during transient conditions.
Solution Approach 2:
The control system implements a feedback mechanism that continuously monitors the actual EGR flow rate, compares it with the desired rate, and adjusts the EGR valve position accordingly. The feedback loop incorporates the rate of change of EGR mass to improve the dynamic response and reduce the time lag between desired and actual EGR flow rates during transient engine operation.
2Use of energy by moving object
If the EGR valve position is adjusted rapidly to match desired EGR flow rate during transient cycles, then fuel efficiency improves, but the system may cause engine misfires due to mismatched EGR and residual gas concentrations
Solution Approach 1:
The control system uses feedback to continuously monitor engine operating conditions and EGR flow rate, adjusting the EGR valve position to maintain optimal EGR levels while preventing conditions that could lead to misfires. The system balances fuel efficiency improvements with engine reliability by making controlled adjustments based on real-time feedback.
Solution Approach 2:
The control system dynamically changes the EGR valve position parameter based on engine operating conditions, particularly during transient cycles. By adjusting this parameter in response to changing conditions and the rate of change of EGR mass, the system optimizes fuel efficiency while maintaining engine stability and preventing misfires.
3Adaptability or versatility
If the EGR control system uses a predetermined desired EGR flow rate without considering the rate of change, then the control algorithm remains simple, but the system cannot adapt to rapid changes in engine load, resulting in transient delays
Solution Approach 1:
The control algorithm performs preliminary calculations of the rate of change of EGR mass and uses this information to proactively adjust the EGR valve position before transient delays occur. This preliminary action based on derivative information enables the system to adapt quickly to changing engine load conditions without requiring complex real-time adjustments.
Solution Approach 2:
The control system transitions from a static predetermined EGR flow rate to a dynamic control approach that considers the rate of change of EGR mass. This dynamic adjustment allows the system to adapt to rapid changes in engine load while maintaining a relatively simple control algorithm structure.
Data Source
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AI summary
A system and method for controlling an exhaust gas recirculation valve during transient cycles of engine operation to improve fuel consumption efficiency. The system and method includes first determining a flow rate of total mass out of the intake manifold of the combustion engine and the current mass fraction of exhaust gas in the intake manifold of the combustion engine, calculating a mass flow rate for exhaust gas into the intake manifold that is based on the flow rate of total mass out of the intake manifold and the current mass fraction of exhaust gas in the intake manifold, and actuating a control valve to a position based on the calculated mass flow rate for exhaust gas into the intake manifold.