Movable Wall Venturi Flow Control for EGR Suction
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Solution Overview
Problem
Existing flow control devices at the junction of air intake and EGR lines face challenges in achieving sufficient EGR gas flow while minimizing pressure losses, especially at low engine speeds where pressure drop is insufficient.
Innovation Solution
A flow control device with a movable wall member and a valve system, actuated by a single mechanism, that adjusts the cross-section of the air intake line to create a Venturi effect only when necessary, allowing for efficient EGR gas suction without excessive pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a Venturi device is used to create pressure drop for EGR gas flow, then EGR flow rate is improved, but pressure losses increase at high engine speeds
Solution Approach 1:
The patent applies a movable wall member that can dynamically adjust the cross-sectional area of the air intake line. The wall member transitions between a retracted position (full cross-section) and an extended position (reduced cross-section), allowing the system to adapt its pressure drop characteristics based on operating conditions. This dynamic adjustment enables sufficient EGR flow at low speeds while minimizing pressure losses at high speeds.
Solution Approach 2:
The invention changes the geometric parameter of the air intake line cross-sectional area by moving the wall member. This parameter change creates a variable Venturi effect, where the cross-section is reduced only when necessary to generate sufficient pressure drop for EGR suction, rather than maintaining a fixed restricted geometry that would cause continuous pressure losses.
2Productivity
If the cross-section of air intake line is reduced to create Venturi effect, then EGR suction is improved, but pressure losses increase
Solution Approach 1:
The movable wall member provides dynamic control of the air intake line cross-section. The wall member is positioned to reduce the cross-section only when EGR suction is required and sufficient pressure drop needs to be generated. At other times, the wall member is retracted to maintain full cross-section and minimize pressure losses, making the Venturi effect conditional rather than continuous.
3Productivity
If a flow control device with adjustable Venturi nozzle is used, then EGR flow control is improved, but device complexity increases
Solution Approach 1:
The flow control device is segmented into functionally independent components: a movable wall member for cross-section adjustment and a shutter valve for flow regulation. The wall member handles the Venturi effect generation while the shutter handles precise flow control, allowing each component to be optimized for its specific function and simplifying the overall design compared to a fully adjustable nozzle.
Solution Approach 2:
The invention merges the EGR flow control function with the air intake line structure by integrating the movable wall member directly into the air intake line wall. This integration eliminates the need for separate adjustable nozzle components while maintaining the ability to create the Venturi effect, thereby reducing device complexity.
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 design ensures a sufficient EGR gas flow while minimizing pressure losses, particularly at low engine speeds, through the creation of a Venturi effect only when required, resulting in better control and fuel efficiency.
Implementation Method 1
the wall member is moved to form a reduced section in the first line. As a result, a depression is created near the first port, by Venturi effect, which allows sucking more second fluid
Data Source
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Figure 9~11
AI summary
The flow control device is positioned at a junction area between a first line (3) carrying a first fluid and a second line (8) carrying a second fluid towards the first line. It comprises: - a wall member (14) forming part of the peripheral wall of the first line, having an opening (16) and being movable so as to reduce the cross-section of the first line, in the vicinity of the opening, from a full section state to a reduced section state; - a valve (20) comprising: - a housing (30) secured to the wall member and having an inner passageway (33) between a first port (31) in fluid communication with the wall member opening and a second port (32) in fluid communication with the second line; - a shutter (40) which can move in the housing between a closed position, in which it closes the inner passageway, and an open position, in which the second fluid can flow through said inner passageway; - an actuator connected to the shutter, which can be moved with respect to the housing, and accordingly move the shutter in said housing, between a first position, corresponding to the closed position of the shutter, and a second position, corresponding to the open position of the shutter, the relative position between the housing and the wall member remaining unchanged during this movement of the actuator, the actuator being further movable from its second position to a third position and to cause, during this further movement, a move of the valve from a neutral position towards a sucking position, and to cause accordingly a move of the wall member secured to the housing, from its full section state towards its reduced section state.