Parallel Aspirator and Ejector for Engine Vacuum Generation
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Solution Overview
Problem
Current internal combustion engine systems with exhaust-driven turbochargers face limitations in efficiency, power control, and vacuum generation, particularly in applications like brake boost, where existing technologies struggle to optimize these aspects effectively.
Innovation Solution
An engine control system incorporating an aspirator and ejector assembly in parallel configuration, connected to the turbocharger, which generates and controls vacuum through fluid communication with the intake manifold, using check valves and multi-port junctions to manage flow paths and vacuum generation, allowing for efficient vacuum creation and application across various engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an exhaust-driven turbocharger is used to improve power output and efficiency, then engine performance is enhanced, but vacuum generation capability becomes limited
Solution Approach 1:
The system divides the vacuum generation function into two separate components: an ejector that uses exhaust gas pressure to create vacuum, and an aspirator that uses intake manifold pressure differential to create vacuum. This segmentation allows the turbocharger to focus on power enhancement while the divided vacuum system ensures reliable vacuum generation under all operating conditions.
Solution Approach 2:
The system changes the operating parameters by using two different pressure sources (exhaust gas pressure for the ejector, intake manifold pressure differential for the aspirator) instead of relying solely on turbocharger vacuum. This parameter diversification ensures vacuum generation reliability across varying engine loads and speeds.
2Device complexity
If a single vacuum source is used to simplify the system, then device complexity is reduced, but adaptability to different engine conditions deteriorates
Solution Approach 1:
The dual-component vacuum system serves multiple functions: the ejector provides vacuum at high engine loads when exhaust pressure is high, while the aspirator provides vacuum at low engine loads when intake manifold pressure differential is high. This multi-functionality allows a single system to adapt to varying engine conditions without requiring complex control mechanisms.
Solution Approach 2:
The system dynamically adapts to different operating conditions through the inherent characteristics of the ejector and aspirator components. As engine load and speed change, the relative effectiveness of each component automatically adjusts, providing optimal vacuum generation across the entire operating range without requiring active control.
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 system enhances engine efficiency and power control by enabling quick and precise vacuum generation, adaptable to different engine conditions, and supports applications like brake boosters and fuel vapor purge control, improving overall engine performance.
Implementation Method 1
an ejector having a motive port (M), a suction port (S), a discharge port (D)... wherein the ejector is configured to generate a vacuum at the suction port (S) when a fluid is supplied to the motive port (M)
Implementation Method 2
an aspirator having a bypass port (B)... wherein the aspirator is configured to generate a vacuum at the bypass port (B) when a fluid is supplied to the aspirator
Data Source
Figure 1
AI summary
An engine system having a flowpath between a junction upstream of a turbocharger and an intake manifold that includes an ejector and an aspirator connected in parallel relative to one another within the flowpath is disclosed. The motive flow through the ejector is in the opposite direction relative to the direction of the motive flow through the aspirator, and both the ejector and the aspirator have a suction port fluidly coupled to a device requiring vacuum. The engine system also includes a first check valve disposed in control of the motive flow through the ejector and a second check valve disposed in control of the motive flow through the aspirator and may also include a control valve in fluid communication within the flowpath upstream or downstream of the ejector and the aspirator that controls the flow into and/or out of both thereof.