Fuel Vapor Pump Air Circulation Cleaning
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Solution Overview
Problem
Existing fuel vapor treatment systems face performance deterioration due to foreign matter accumulation in vane type pumps, leading to potential rotor lockage and abrasive wear, which affects the accuracy of fuel vapor leak detection.
Innovation Solution
A fuel vapor treatment system incorporating a purge passage, canister, purge valve, pump passages, selector valve, pressure detector, and control unit that allows for foreign matter removal by circulating atmospheric air through the pump, maintaining stable pump performance and accurate leak detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vane type pump is used to depressurize or pressurize the fuel tank, then the pump performance is initially good, but foreign matter accumulation causes clearance decrease and performance deterioration over time
Solution Approach 1:
The system performs preliminary cleaning action by circulating atmospheric air through the pump before foreign matter accumulation significantly impacts performance. The control unit periodically activates the air circulation mode to prevent clearance decrease between rotor and housing, maintaining pump reliability throughout the service life.
Solution Approach 2:
The pump system performs self-maintenance by using its own structure to circulate atmospheric air through the pump interior. The atmospheric air flow automatically removes foreign matters and worn powders from the pump, eliminating the need for external maintenance systems while preserving pump performance stability.
2Manufacturing precision
If foreign matters are introduced into the pump or worn powders accumulate, then the clearance between rotating and stationary parts decreases improving initial sealing, but rotor lockage and abrasive wear occur
Solution Approach 1:
The system converts atmospheric air, which is normally just ambient environment, into a beneficial cleaning medium. The atmospheric air flow carries foreign matters and worn powders out of the pump, transforming the harmful accumulation effect into a beneficial removal process that prevents rotor lockage and abrasive wear.
Solution Approach 2:
The control unit changes the operational parameter by switching between fuel vapor processing mode and air circulation cleaning mode. During air circulation mode, atmospheric pressure and flow rate parameters are adjusted to optimize foreign matter removal from the pump interior, preventing clearance degradation.
3Measurement precision
If the pump operates continuously to maintain fuel vapor treatment, then the leak detection accuracy is maintained, but foreign matter accumulation accelerates
Solution Approach 1:
The control unit implements periodic action by alternating between fuel vapor processing operations and air circulation cleaning operations. This periodic switching prevents continuous operation-induced foreign matter accumulation while maintaining adequate leak detection accuracy through scheduled cleaning cycles that restore pump efficiency.
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 prevents pump performance deterioration by removing foreign matters, ensuring long-term stability and high accuracy in determining fuel vapor leaks.
Implementation Method 1
The canister is provided in the purge passage for adsorbing a part of the fuel vapor flowing through the purge passage
Implementation Method 2
The pump can depressurize or pressurize the interior of the fuel tank through the second pump passage, the first pump passage, the canister, and the first purge passage
Implementation Method 3
controls the selector valve to connect a first pump passage and the second pump passage so as to circulate an atmospheric air in the pump while the purge valve is opened to introduce the fuel vapor into the internal combustion engine, whereby a foreign matter in the pump can be removed
Data Source
AI summary
An ECU controls a selector valve so as to connect a first pump passage and a second pump passage, and determines whether a fuel vapor leak from a fuel tank is in an allowable range based on a pressure in the fuel tank which is detected by a pressure sensor while a pump is driven to decrease a pressure in the fuel tank. The ECU opens a purge valve, whereby the fuel vapor adsorbed by a canister is introduce into an engine through an intake passage. The ECU controls the selector valve to connect a first pump passage and the second pump passage so as to circulate an atmospheric air in the pump while the purge valve is opened to introduce the fuel vapor into the internal combustion engine, whereby a foreign matter in the pump can be removed.