Fuel System Depressurization via Intake Manifold Flow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In hybrid vehicles, reduced engine running times and potential degradation of the fuel tank pressure sensor make it difficult to accurately infer fuel tank depressurization, leading to issues such as locked fuel doors and premature refueling attempts, which can result in fuel mist exposure and increased hydrocarbon emissions.
Innovation Solution
A method that directs fuel tank vapors to the engine intake manifold and uses the mass air flow sensor to indicate depressurization, ensuring the fuel door remains locked until complete depressurization is confirmed, thereby relying on existing sensors to enhance reliability and prevent fuel spray and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fuel door is unlocked immediately after engine shutdown, then refueling convenience is improved, but fuel mist exposure risk increases due to potential pressure build-up
Solution Approach 1:
The system performs preliminary action by automatically initiating depressurization procedures immediately upon engine shutdown. The fuel system control unit detects engine shutdown and proactively activates venting mechanisms to equalize pressure before the refueling operation begins. This preliminary pressure management action prevents harmful pressure build-up while enabling convenient refueling.
Solution Approach 2:
The system applies preliminary anti-action by implementing preventive measures against pressure build-up before refueling occurs. The control unit monitors pressure conditions and activates counteracting venting operations in advance, preventing the development of dangerous pressure differentials that would cause fuel mist exposure. This preliminary protective action eliminates the harmful effect before it can manifest.
2Loss of energy
If engine running time is reduced in hybrid vehicles, then fuel economy is improved, but the ability to use temperature variation for depressurization inference deteriorates
Solution Approach 1:
The patent applies universality by making the engine's atmospheric pressure sensing capability serve multiple functions. The same pressure sensors and engine control unit that manage engine operation also perform fuel tank depressurization monitoring and refueling safety verification. This multi-functional use of existing engine components eliminates the need for additional temperature sensing infrastructure while maintaining depressurization inference accuracy despite reduced engine running times.
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
This approach reliably determines fuel tank depressurization even with a degraded pressure sensor, ensuring safe refueling and reducing hydrocarbon emissions by using the mass air flow sensor to confirm depressurization, thus protecting the operator and improving fuel system integrity.
Implementation Method 1
indicating depressurization of a fuel tank based on an output of a mass air flow sensor coupled to the intake manifold
Implementation Method 2
directing fuel tank vapors to an engine intake manifold
Data Source
AI summary
Methods and systems are provided for accurately confirming fuel tank depressurization before unlocking a fuel door to enable refueling. Following a refueling request, a fuel system may be sealed from the atmosphere while one or more fuel system valves are adjusted to divert fuel tank pressure or vacuum to an engine intake. Depressurization may be inferred based on the presence of air or vapor flow into the intake as sensed by a manifold airflow sensor.