Purge Ejector Assembly for Engine Fuel Vapor Control
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Solution Overview
Problem
Current vehicle fuel systems face challenges in efficiently purging fuel vapors from the charcoal canister to the engine, especially under varying engine conditions such as idle and boost pressure, which affects emissions compliance and system performance.
Innovation Solution
A purge ejector assembly with a configuration of fluid passages and valves that allows for controlled flow of evaporated fuel from the canister to the engine manifold, utilizing a nozzle to increase air flow velocity and check valves to manage flow direction based on pressure conditions, enabling efficient purging under both negative and positive pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional purge valve is used to control fuel vapor flow, then the system can regulate purge amount, but the system cannot effectively purge the canister under both negative and positive pressure conditions
Solution Approach 1:
The purge ejector assembly uses dynamic check valves that automatically change flow direction based on pressure conditions. The first check valve allows flow from engine manifold to canister under negative pressure, while the second check valve allows flow from canister to engine manifold under positive pressure, enabling adaptive purge control without complex external actuators
Solution Approach 2:
The system uses the engine's own intake manifold pressure to drive the purge process. Under negative pressure, the pressure differential automatically opens the first check valve to allow purge flow. Under positive pressure, the pressure differential automatically opens the second check valve, eliminating the need for external power sources or complex control mechanisms
2Power
If a compressor such as turbo charger is used to improve engine performance, then engine power is increased, but the purging process becomes more difficult under boost pressure conditions
Solution Approach 1:
The invention converts the harmful effect of positive boost pressure into a beneficial force for purging. The second check valve is positioned to allow fuel vapor to flow from the canister to the engine manifold when positive pressure is applied, using the boost pressure itself to drive the purge process that would otherwise be inhibited by the compressor
3Adaptability or versatility
If multiple valves and fluid passages are added to control purge flow under different pressure conditions, then purge adaptability is improved, but assembly complexity and risk of erroneous installation increase
Solution Approach 1:
The first and second check valves are positioned asymmetrically within the housing, with the first check valve oriented for negative pressure operation and the second check valve oriented for positive pressure operation. This asymmetric arrangement, combined with corresponding asymmetric fluid passages, creates a self-aligning structure that prevents erroneous assembly
Solution Approach 2:
Multiple functional components (check valves, fluid passages, nozzle device) are merged into a single integrated purge ejector assembly housing. This consolidation reduces the number of separate parts that need to be assembled and reduces the risk of installation errors while maintaining the complex internal flow control functionality
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 solution effectively controls the purging process across different engine conditions, improving emissions compliance and system performance while simplifying installation and reducing the risk of erroneous assembly.
Implementation Method 1
a nozzle device (20) disposed in said first fluid passage (111) and configured to raise the flow velocity of the air flowing in said first fluid passage
Implementation Method 2
a nozzle device (20) disposed in said first fluid passage (111) and configured to raise the flow velocity of the air flowing in said first fluid passage
Data Source
Figure 1
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AI summary
The present invention relates to a purge ejector assembly (10) for an engine, comprising: a first fluid passage (111); a nozzle device (20) disposed in said first fluid passage (111) and configured to raise the flow velocity of the air flowing in said first fluid passage (111); a first valve (30) disposed in said first fluid passage (111) at a position in-between an engine manifold port (122) and said nozzle device (20), said first valve (30) being configured to permit fluid to flow through said first valve (30) from said engine manifold port (122) toward said nozzle device (20), while restricting fluid to flow through said first valve from said nozzle device (20) toward said engine manifold port (122); a second fluid passage (113); a second valve (40) disposed in said second fluid passage (113) at a position in-between said engine manifold port (122) and a purge flow port (118), said second valve (40) being configured to permit fluid to flow through said second valve (40) from said purge flow port (118) toward said engine manifold port (122), while restricting fluid to flow through said second valve (40) from said engine manifold port (122) toward said purge flow port (118); a third fluid passage (115) extending from a second fluid passage position (124) located between said purge flow port (118) and said second valve (40) to a first fluid passage position (126) located between said nozzle device (20) and an air duct port (112); a third valve (50) disposed in said third fluid passage (115) and configured to permit fluid to flow through said third valve (50) from said purge flow port (118) toward said air inlet channel port (112), while restricting fluid to flow through said third valve (50) from said air inlet channel port (112) toward said purge flow port (118). The present invention also relates to a vehicle comprising an evaporation fuel purge system (102) having a purge ejector assembly (10).