Evaporated Fuel Processing Device Noise Reduction
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Solution Overview
Problem
Existing evaporated fuel processing devices with sealed fuel tanks generate abnormal noise due to sudden pressure variations when introducing atmospheric pressure to counteract negative pressure, primarily because of the large size of the electromagnetic blocking valve used for smooth refueling.
Innovation Solution
Incorporating a second purge control valve with a smaller passage area than the blocking valve, which opens to introduce atmospheric pressure into the fuel tank before the blocking valve, allowing for a gentler introduction of pressure and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large electromagnetic blocking valve is used to maintain smooth refueling, then refueling efficiency is improved, but abnormal noise is generated when introducing atmospheric pressure to the fuel tank
Solution Approach 1:
The patent divides the single blocking valve function into two separate valves: a blocking valve (21) for refueling operations and a second purge control valve (32) for pressure equalization. This segmentation allows each valve to be optimized for its specific function - the blocking valve can be large for smooth refueling while the second purge control valve is small for gentle pressure introduction, eliminating the noise problem
Solution Approach 2:
The second purge control valve (32) acts as an intermediary device between the atmosphere and the fuel tank. It provides a controlled, gradual pressure equalization path through the canister before the blocking valve opens, preventing sudden gas flow and noise generation while still allowing the blocking valve to perform its refueling function efficiently
2Reliability
If the blocking valve is opened to introduce atmospheric pressure when the fuel tank reaches negative pressure, then the negative pressure is relieved, but sudden gas flow causes abnormal noise
Solution Approach 1:
The second purge control valve (32) performs preliminary pressure equalization before the blocking valve (21) opens. By introducing atmospheric pressure gradually through the canister first, the system prepares for the blocking valve opening, ensuring that when it does open, the pressure difference is reduced and noise is minimized
Solution Approach 2:
The patent changes the flow rate parameter by using two different valve sizes for different operations. The second purge control valve (32) has a smaller passage area for gentle pressure equalization, while the blocking valve (21) has a larger passage area for rapid refueling. This parameter differentiation allows the system to achieve both noise-free pressure relief and efficient refueling
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 solution effectively suppresses abnormal noise by gradually increasing pressure within the fuel tank, preventing excessive negative pressure and maintaining a sealed state without compromising refueling efficiency.
Implementation Method 1
when the fuel tank reaches a negative pressure, with a blocking valve being closed, the second purge control valve is opened to introduce an atmospheric pressure through the canister to the fuel tank
Implementation Method 2
arranged to temporarily adsorb an evaporated fuel generated in a fuel tank of a vehicle to a canister using adsorption material (adsorbent) such as activated carbon
Data Source
AI summary
An evaporated fuel processing device includes: an evaporated fuel passage connecting a fuel tank and a canister; a purge passage connecting the canister and an intake passage of an internal combustion engine a first purge control valve arranged to open and close the purge passage; a tank open passage connecting a position on an upstream side of the first purge control valve in the purge passage, and the tank; and a second purge control valve arranged to open and close the tank open passage, when the fuel tank becomes a negative pressure, the second purge control valve being opened to introduce an atmospheric pressure through the canister.