EGR Valve Controller Limits Exhaust Flow via Differential Pressure Feedback
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Solution Overview
Problem
The excessive buildup of particulate matter in a filter of an internal combustion engine leads to increased pressure on the upstream side, causing an excessive flow of exhaust gas into the intake passage, which reduces engine controllability due to the EGR valve's inability to manage differential pressure effectively.
Innovation Solution
A controller that limits the opening degree of the EGR valve based on the amount of particulate matter trapped, using differential pressure thresholds to adjust the valve's operation and prevent excessive exhaust gas flow into the intake passage, thereby maintaining engine controllability and minimizing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filter traps more particulate matter, then the filtration performance improves, but the pressure on the upstream side of the filter increases excessively
Solution Approach 1:
The controller continuously monitors the differential pressure across the filter and uses this feedback to dynamically adjust the EGR valve opening degree. When the upstream pressure exceeds a predetermined threshold, the controller limits the EGR valve opening to prevent excessive exhaust gas flow, thereby resolving the contradiction between maintaining filtration performance and controlling upstream pressure.
2Productivity
If the EGR valve opening degree is increased to improve engine performance, then the exhaust gas recirculation increases, but the exhaust gas flow becomes excessive when differential pressure is high
Solution Approach 1:
The EGR valve opening degree is dynamically adjusted based on real-time differential pressure conditions. The controller limits the opening degree to a predetermined value or smaller when the differential pressure exceeds the threshold, preventing excessive exhaust gas flow into the intake passage while allowing full opening under normal conditions to maintain engine performance.
3Object-generated harmful factors
If the EGR valve opening is limited to control exhaust gas flow, then the exhaust gas flow into intake passage decreases, but the engine controllability deteriorates
Solution Approach 1:
The controller changes the operating parameters of the EGR valve based on differential pressure conditions. By adjusting the opening degree parameter dynamically - allowing full opening when pressure is normal and limiting it when pressure exceeds threshold - the system maintains engine controllability while preventing harmful exhaust gas flow under critical 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
The controller effectively limits the exhaust gas flow into the intake passage, maintaining engine controllability and reducing fuel consumption by dynamically adjusting the EGR valve's opening degree in response to varying particulate matter accumulation and differential pressures.
Implementation Method 1
a filter that traps particulate matter in exhaust gas
Implementation Method 2
an EGR valve that adjusts the cross-sectional flow area of the EGR passage
Data Source
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AI summary
An internal combustion engine includes a filter, which is configured to trap particulate matter in exhaust gas, an EGR passage, which connects a section of an exhaust passage that is upstream of the filter to an intake passage, and an EGR valve, which is configured to adjust a cross-sectional flow area of the EGR passage. A controller for the internal combustion engine includes processing circuitry, which is configured to execute a limiting process of limiting an opening degree of the EGR valve such that the opening degree is likely to decrease when an amount of the particulate matter trapped by the filter is great as compared to when the amount is small.