Two-Stage Fuel Vapor Return System for Charge Air Pressure Preservation
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Solution Overview
Problem
Existing vapor return systems for fuel vapor collecting tanks in vehicles are inefficient in reintroducing fuel vapor into the combustion process, leading to unnecessary loss of charge air pressure and increased energy consumption due to prolonged operation of the venturi nozzle.
Innovation Solution
A two-stage vapor return system with separate branches connected to the charge air duct and a venturi nozzle suction inlet, controlled by stop valves and an engine control module, allowing for efficient introduction of fuel vapor into the engine and minimizing venturi nozzle operation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the venturi nozzle is operated for a prolonged period to evacuate fuel vapor from the collecting tank, then complete vapor removal is achieved, but charge air pressure is significantly reduced and energy consumption increases
Solution Approach 1:
The vapor evacuation process is divided into two distinct phases: a first phase using the charge air duct with high pressure to remove the majority of vapor, and a second phase using the venturi nozzle to remove residual vapor. This segmentation allows the system to achieve complete evacuation while minimizing the time the venturi nozzle operates, thereby preserving charge air pressure.
Solution Approach 2:
The system employs periodic action by sequentially activating different vapor return branches based on the evacuation progress. The control unit opens the first stop valve for the charge air duct phase, then switches to the second stop valve for the venturi nozzle phase, creating distinct operational periods that optimize both evacuation efficiency and pressure maintenance.
2Reliability
If the venturi nozzle operates for an extended duration to ensure complete vapor removal, then vapor evacuation is thorough, but energy consumption increases
Solution Approach 1:
The evacuation process is segmented into two phases with different energy requirements. The first phase using the charge air duct handles the bulk vapor removal with lower energy input, while the second phase using the venturi nozzle handles only residual vapor with higher energy input, minimizing total energy consumption while ensuring complete evacuation.
Solution Approach 2:
The system applies partial action by using the high-energy venturi nozzle only for the portion of vapor that remains after the first phase, rather than operating it continuously. This partial application of high-energy action achieves complete evacuation with minimized energy expenditure.
3Reliability
If the venturi nozzle is bridged across the throttle flap to evacuate vapor, then vapor removal is effective, but charge air pressure is lost throughout the entire evacuation period
Solution Approach 1:
The system segments the vapor removal process into two distinct pathways: the first branch using the charge air duct for initial vapor removal, and the second branch using the venturi nozzle with bypass for residual vapor. This segmentation ensures that the charge air pressure loss is confined to a minimal period during the second phase only.
Solution Approach 2:
The system performs preliminary action by removing the majority of vapor through the charge air duct before activating the venturi nozzle. This preliminary evacuation reduces the vapor load, allowing the subsequent venturi nozzle operation to be brief and thus minimizing charge air pressure loss.
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 effectively reduces charge air pressure loss and energy consumption by implementing a two-phase vapor return process, ensuring complete vapor evacuation with reduced venturi nozzle operation, and integrates seamlessly with existing engine control systems.
Implementation Method 1
a venturi nozzle, which is either integrated into the charge air duct or situated in a bypass line, which circumvents a throttle flap in the charge air duct
Implementation Method 2
the first vapor return branch is connected by a first cheek valve to the charge air duct
Data Source
AI summary
A vapor return system of a fuel vapor collecting tank includes a vapor outlet line with a first stop valve, which is arranged in the vapor outlet line of the fuel vapor collecting tank. A first vapor return branch is arranged between the vapor outlet line of the fuel vapor collecting tank and a charge air duct of a compressor in a turbocharger. A second vapor return branch is arranged between the vapor outlet line of the fuel vapor collecting tank and a fresh air suction duct of the compressor of the turbocharger. The first vapor return branch is connected by a first check valve to the charge air duct. The second vapor return branch is connected by a second check valve to a suction inlet of a venturi nozzle situated in a bypass line between the charge air duct and fresh air suction duct via a second stop valve.