EGR Control Flap Surface Geometry for Intake Pressure Loss Reduction
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Solution Overview
Problem
Existing control devices for internal combustion engines experience increased pressure losses and condensation issues when regulating exhaust gas recirculation, leading to damage in downstream compressors due to mixing of exhaust gas and air flows.
Innovation Solution
A control device with a control body that, in its second end position, has a surface shape perpendicular to the intake duct's inner wall, preventing vortices and delaying gas mixing, thereby reducing pressure losses and condensation, and featuring a continuous flow transition between duct sections to minimize pressure losses and enhance compressor inflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control element is positioned upstream of the compressor to regulate exhaust gas recirculation, then the control of exhaust gas and airflow is improved, but condensation problems occur when exhaust gas mixes with airflow, potentially damaging the compressor
Solution Approach 1:
The control element is positioned laterally adjacent to the airflow path rather than directly in the flow path, allowing control functionality while maintaining dimensional separation between the control mechanism and the gas streams to prevent condensation
Solution Approach 2:
The control element acts as an intermediary that regulates exhaust gas recirculation without directly mixing with the main airflow, enabling precise control while avoiding the harmful condensation effect on the compressor
2Ease of operation
If conventional control devices regulate exhaust gas recirculation, then the regulation function is achieved, but pressure losses increase in both fully open and restricted positions
Solution Approach 1:
The control element is positioned at a specific location where it can regulate exhaust gas recirculation with minimal interference to the main airflow path, creating local control quality that reduces overall pressure losses while maintaining regulation effectiveness
Solution Approach 2:
By positioning the control element laterally adjacent to rather than directly in the airflow path, the design separates the control function from the main flow path, enabling regulation with reduced pressure losses in both open and restricted positions
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
Significantly reduces pressure losses and condensation, allowing for precise and efficient regulation of air and exhaust gas flows, protecting downstream compressors from damage and improving engine filling and compressor efficiency.
Implementation Method 1
the shape of a surface of the control element facing the interior of the intake duct, in the second end position, corresponds in a cross-section perpendicular to the central axis of the first housing part at an angle of at least 90° to an inner wall surface of the first duct section adjacent to the control element, so that the first duct section is extended over a circumferential section in a substantially undisturbed manner
Implementation Method 2
This prevents turbulence in the area of the exhaust gas inlet or on the outer surfaces of the control element, thus achieving a significant reduction in pressure losses
Implementation Method 3
Simultaneously, this flow pattern delays the mixing of the warm exhaust gas stream with the cold air stream, thereby reducing the amount of condensate produced
Data Source
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AI summary
Control devices for internal combustion engines are known with an intake duct (12), an exhaust gas recirculation duct (16) which opens into the intake duct (12), a housing (10), in which the intake duct (12) and at least one opening (14) of the exhaust gas recirculation duct (16) are configured, a shaft (36) which serves as a rotational axis (38) and is arranged in the housing (10) upstream of the opening (14) of the exhaust gas recirculation duct (16) with regard to the air flow and outside the throughflow cross section of a first duct section (19) of the intake duct (12), a control body (42) which is fastened eccentrically to the shaft (36), a first duct section (19), at the downstream end of which a first valve seat (50) is configured, against which the control body (42) bears in a first end position, and a second valve seat (72) on the second duct section, against which second valve seat (72) the control body (42) bears in a second end position. Said control devices have the disadvantage, however, of an increased pressure loss as a result of undesired eddy formation. In order to solve said problem, it is proposed according to the invention that the shape of a surface (54) of the control body (42), which surface (54) points towards the interior of the intake duct (12), in the second end position corresponds in a cross section perpendicularly with respect to the centre axis (20) over an angle of at least 90° to an inner wall surface (56) of the first duct section (19), which inner wall surface (56) adjoins the control flap (42).