Electric Pump-Assisted EGR Control for Transient Engine Response
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Solution Overview
Problem
Internal combustion engine air handling systems face challenges in responding effectively to transient operating conditions, particularly in controlling exhaust gas recirculation (EGR) to ensure optimal engine performance and emissions management.
Innovation Solution
An air handling system for internal combustion engines that includes an EGR passageway fluidly coupled between the exhaust and intake manifolds, an EGR valve, an electric gas pump to enhance flow rate, and a control circuit that determines the need for pump activation based on target engine speed and fueling targets, using models to calculate maximum achievable flow rates and control valve positions to optimize EGR flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an electric gas pump is added to increase EGR flow rate, then the responsiveness to transient conditions is improved, but the device complexity increases
Solution Approach 1:
An electric gas pump is introduced as an intermediary component in the EGR system to actively enhance exhaust gas flow rates during transient operating conditions. The pump is positioned in the EGR passageway between the EGR cooler and EGR valve, and is selectively activated based on pump enable values calculated from target engine speed and fueling conditions, allowing rapid response to transient demands without permanently increasing system complexity.
2Quantity of substance
If the EGR valve is kept fully open to maximize flow rate, then the EGR flow capability is improved, but the control precision over EGR flow rate is worsened
Solution Approach 1:
The EGR valve is operated dynamically rather than being held in a fixed fully open position. The control system continuously adjusts the EGR valve position based on calculated pump enable values that consider target engine speed, total fueling target, and desired EGR flow rates. This dynamic control allows the system to maintain precise EGR flow rate control while achieving maximum flow capability when needed through coordinated valve and pump operation.
3Speed
If the electric gas pump is activated frequently to meet transient EGR demands, then the responsiveness is improved, but the energy consumption increases
Solution Approach 1:
The control system calculates pump enable values in advance based on target engine speed and total fueling target before transient conditions fully develop. This preliminary calculation allows the system to proactively activate the electric gas pump only when and where needed, rather than continuously operating it. The pump is activated selectively based on whether the calculated pump enable value exceeds a threshold, reducing unnecessary energy consumption while maintaining responsiveness to actual transient demands.
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 system provides a responsive air handling system capable of quickly adjusting to transient conditions by enhancing EGR flow rates when needed, improving engine performance and emissions control.
Implementation Method 1
an electric gas pump increasing, when activated, the flow rate of exhaust gas through the EGR passageway
Implementation Method 2
an EGR valve disposed in-line with the EGR passageway, the EGR valve controllable between fully closed and fully open positions to control a flow rate of exhaust gas through the EGR passageway
Data Source
AI summary
A system controlling an air handling system for an internal combustion engine. An EGR valve in-line with an EGR passageway fluidly coupled between exhaust and intake manifolds of the engine is controllable between fully closed open positions to control a flow rate of exhaust gas through the EGR passageway. A control circuit determines a pump enable value as a function of at least one of a target engine speed and a total fueling target, determines a maximum achievable flow rate of recirculated exhaust gas through the EGR passageway with the EGR valve in the fully open position, and activates an electric gas pump to increase the flow rate of exhaust gas through the EGR passageway if the pump enable value exceeds a threshold pump enable value and a target flow rate of recirculated exhaust gas through the EGR passageway is less than the maximum achievable flow rate.