Dual Venturi Ejector for Broad Vacuum Range
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Solution Overview
Problem
Conventional ejectors are limited in producing vacuum pressure below atmospheric pressure, especially in boosted engines operating above 135 kPa absolute, as the location of minimum vacuum creation shifts within the device with varying motive pressures, restricting their operational range.
Innovation Solution
A Venturi device with two Venturi gaps, where the second gap is positioned downstream of the first, creating multiple suction points along the discharge section, allowing for suction at different locations and enhancing vacuum production across a range of motive pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single Venturi gap ejector is used, then the structure is simple, but the vacuum production capability is limited when motive pressure exceeds 192 kPa absolute
Solution Approach 1:
The ejector is divided into multiple functional sections with two separate Venturi gaps positioned at different locations along the discharge passage. Each Venturi gap creates a suction region that operates effectively at different motive pressure ranges, allowing the device to maintain reliable vacuum production across a broader pressure spectrum while keeping individual sections relatively simple
2Productivity
If motive pressure is increased to improve vacuum production, then suction capability improves at low pressures, but the location of minimum pressure shifts and vacuum production decreases at high pressures
Solution Approach 1:
Different sections of the discharge passage are designed with different characteristics - the first Venturi gap is positioned to create optimal suction at lower motive pressures while the second Venturi gap is positioned downstream to create optimal suction at higher motive pressures. This local differentiation allows each section to excel at its designated pressure range, providing adaptability across the full operational spectrum
3Volume of moving object
If a single Venturi gap is used, then the device is compact, but it cannot maintain effective vacuum production across varying boost pressures
Solution Approach 1:
Instead of increasing the size of a single Venturi gap, the invention adds a second dimension to the suction creation by positioning two Venturi gaps at different locations along the discharge passage. This spatial arrangement allows the ejector to handle varying pressure ranges without significantly increasing overall device volume, as the two gaps work in sequence rather than requiring a larger single gap
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 multi-Venturi device effectively produces usable vacuum over a broader range of motive pressures, improving suction flow rates and reducing turbulence, thereby overcoming the limitations of single Venturi gap ejectors.
Implementation Method 1
By passing pressurized air through the ejector, a low pressure region may be created within the ejector so that air can be drawn from a vacuum reservoir
Data Source
AI summary
Venturi devices and systems incorporating the same are disclosed. The Venturi devices include a lower body defining a passageway having a motive section and a discharge section spaced a distance apart from one another to define a first Venturi gap and a second Venturi gap downstream of the first Venturi gap at a position that divides the discharge section into a first portion between the first and second Venturi gaps and a second portion leading away from the second Venturi gap, and include an upper body defining a suction passageway in fluid communication with both the first and second Venturi gaps. The motive section and the discharge section converge toward the first Venturi gap.