Restrictors using the venturi effect
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Solution Overview
Problem
Existing restrictors in positive crankcase ventilation systems fail to maintain a constant fluid flow due to variations in manifold pressure, leading to potential flow disruptions and deposit formation on valving components.
Innovation Solution
The use of restrictors with inlet and outlet cones transitioning as hyperbolic or parabolic functions, which ensure a nearly constant flow rate by achieving sonic velocity at the throat, minimizing vena contracta variation and reducing turbulence, thereby maintaining a consistent mass flow rate independent of pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional straight cone restrictors are used, then the device complexity is low, but the flow rate varies with pressure changes
Solution Approach 1:
The patent applies curved surfaces by transitioning from straight cone shapes to hyperbolic and parabolic cone shapes. The hyperbolic inlet cone and parabolic outlet cone create a smooth curved transition that optimizes flow characteristics, eliminates turbulence, and maintains constant flow rate across varying pressure conditions while achieving sonic velocity at the throat.
2Reliability
If restrictors are used to control flow, then flow control is achieved, but deposit formation occurs on valving components
Solution Approach 1:
The patent converts the potential harm of pressure variations and flow disruptions into beneficial effects by designing hyperbolic and parabolic cone shapes that eliminate turbulence and maintain smooth, laminar flow. This prevents deposit formation on valving components while ensuring stable flow control, effectively turning the challenge of flow management into an advantage.
3Object-affected harmful factors
If restrictors are used in crankcase ventilation, then emissions are reduced, but flow variations disrupt engine calibration
Solution Approach 1:
The patent changes the geometric parameters of the restrictor from traditional straight cone shapes to hyperbolic and parabolic configurations. This parameter change optimizes the flow characteristics, ensuring that the restrictor maintains a constant flow rate regardless of pressure variations, thereby preventing disruptions to engine calibration while still achieving emissions reduction.
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 described restrictor design achieves superior performance by maintaining a constant flow rate and reducing material costs, with hyperbolic and parabolic shapes outperforming traditional straight cone designs across various pressure drops, minimizing turbulence and deposit formation.
Implementation Method 1
Restrictors using the venturi effect for producing a generally constant flow of fluid therethrough during operating pressure changes
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3
AI summary
Restrictors are disclosed that include a body defining a Venturi tube having a throat defining a junction of a converging inlet cone to a diverging outlet cone along a longitudinal axis thereof, and with the converging inlet cone and the diverging outlet cone each defining an inner passageway that transitions as a hyperbolic or parabolic function toward the throat.