Modular Fuel Vapor Purging Ejector for Boosted Engines
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Solution Overview
Problem
Existing fuel vapor purging systems in boosted engines are complex, costly, and prone to leakage due to numerous connections and components, making them difficult to assemble and maintain, especially when operating under varying intake manifold pressure conditions.
Innovation Solution
A simplified fuel vapor purging system using an ejector with fewer connections, where vapors are purged into the intake passage downstream of the throttle during vacuum conditions and into the upstream inlet of the compressor during boost conditions, leveraging pressure differentials to achieve efficient vapor flow without the need for multiple check valves and complex connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dual-path system with multiple check valves and connections is used for fuel vapor purging in boosted engines, then the system can purge under both vacuum and boost conditions, but the system becomes complex, costly, and prone to leakage
Solution Approach 1:
The patent merges the vacuum and boost purge paths into a single integrated path using a bypass valve. Instead of maintaining separate dual-path systems with multiple check valves, the invention combines both purging functions into one pathway that adapts to different pressure conditions through the bypass valve mechanism, thereby reducing component count and complexity while maintaining versatility.
Solution Approach 2:
The bypass valve serves multiple functions: it acts as a check valve during vacuum conditions to allow purge flow, and as a pressure relief valve during boost conditions to enable purging against positive pressure. This multi-functionality eliminates the need for separate components for each condition, reducing overall system complexity while maintaining adaptability across different operating modes.
2Adaptability or versatility
If a dual-path system with approximately 11 connections is used for fuel vapor purging, then purging can be achieved under varying pressure conditions, but the system becomes prone to vapor leakage and difficult to assemble
Solution Approach 1:
By merging the vacuum and boost purge paths into a single integrated pathway, the invention dramatically reduces the number of connections from approximately 11 to a minimal set. This consolidation eliminates multiple potential leakage points while maintaining the ability to purge under both vacuum and boost conditions through the intelligent operation of the bypass valve.
Solution Approach 2:
The invention extracts and eliminates unnecessary components (multiple check valves and redundant connections) from the dual-path system, retaining only the essential single pathway and bypass valve mechanism. This extraction reduces the connection count and removes potential failure points for vapor leakage while preserving the core purging functionality across different pressure conditions.
3Adaptability or versatility
If a dual-path system with two check valves and an ejector is used, then fuel vapor purging can be achieved during both vacuum and boost conditions, but assembly becomes difficult and plug-and-play assembly is not possible
Solution Approach 1:
The invention merges multiple discrete components (two check valves and ejector) into a single integrated bypass valve assembly. This consolidation creates a modular unit that can be assembled as one complete sub-system and installed in a single location, enabling plug-and-play assembly while maintaining the capability to handle both vacuum and boost purging conditions through the bypass valve's dual-mode operation.
4Device complexity
If a simplified system with fewer connections is used for fuel vapor purging, then costs are reduced and assembly is easier, but vapor flow may be compromised under varying pressure conditions
Solution Approach 1:
The bypass valve is designed as a dynamic component that automatically adjusts its flow characteristics based on real-time pressure conditions. During vacuum conditions, it opens to allow maximum purge flow; during boost conditions, it modulates to maintain appropriate flow rates against positive pressure. This dynamic adaptation ensures optimal vapor flow rates are maintained across all operating conditions despite the simplified single-path architecture.
Solution Approach 2:
The system changes the operational parameters of the bypass valve based on intake manifold pressure conditions. The valve transitions between different flow states (open, partially open, closed) depending on whether the engine is operating under vacuum or boost, thereby maintaining effective vapor flow rates across varying pressure conditions while using a simplified component structure.
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 reduces costs, minimizes leakage, facilitates easier assembly, and maximizes vapor flow across various operating conditions, including both vacuum and boost conditions, by utilizing fewer components and connections while ensuring reliable fuel vapor purging.
Implementation Method 1
pressure differentials within the engine may be utilized to draw fuel vapors from the canister into the intake manifold
Data Source
AI summary
Methods and systems for fuel vapor canister purging in boosted engines are described. In one example, vapors are purged from the canister into an engine intake passage downstream of a throttle via an ejector during vacuum conditions, whereas during boost conditions, vapors are purged from the canister into an upstream inlet of a compressor via the ejector, the compressor arranged in the intake passage upstream of the throttle.