Vaporized Fuel Leakage Detection Using Density and Pressure Sensors
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Solution Overview
Problem
Existing leakage detecting devices for vaporized fuel in automotive vehicles have limited detection accuracy and require specific operating conditions, restricting the range of conditions under which leakage determination can be performed.
Innovation Solution
A leakage detecting device incorporating a first sensor for density and a second sensor for pressure, along with a leakage determination portion and a determination resetting portion, which assess time-variable amounts of these parameters to determine and reset leakage, allowing for high detection accuracy across a broader range of engine and vehicle operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If leakage determination is performed only after engine operation stops and temperature stabilizes, then detection accuracy is improved, but the range of operating conditions for leakage determination is restricted
Solution Approach 1:
The patent changes the physical parameters used for leakage detection from solely pressure-based measurements to combined density and pressure measurements. The first sensor detects density of vaporized fuel, while the second sensor detects pressure. By utilizing these different physical parameters simultaneously, the system achieves accurate leakage detection across various operating conditions without requiring temperature stabilization, thus resolving the contradiction between detection accuracy and adaptability to different operating conditions
Solution Approach 2:
The patent introduces a determination resetting portion that acts as an intermediary to evaluate time-variable amounts of both density and pressure. This intermediary component processes the combined information from both sensors and makes the final leakage determination, allowing the system to maintain high detection accuracy while operating under diverse conditions including during engine operation, thereby expanding the range of applicable operating conditions
2Measurement precision
If leakage determination requires predetermined time to pass after engine operation stops, then detection accuracy is improved, but loss of time occurs
Solution Approach 1:
The patent changes the measurement parameters to include real-time density detection in addition to pressure detection. This allows the system to perform accurate leakage determination immediately during various operating conditions without waiting for temperature stabilization, thereby eliminating the time loss while maintaining high detection accuracy
Solution Approach 2:
The determination resetting portion continuously monitors and evaluates time-variable amounts of density and pressure in advance, preparing the system to make immediate leakage determinations when needed. This preliminary continuous monitoring eliminates the need to wait for predetermined time periods after engine operation stops, thus reducing time loss while maintaining accuracy
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 device achieves high detection accuracy for vaporized fuel leakage while enabling the leakage determination process to be performed under various operating conditions, including those not previously feasible, thereby expanding the operational range of the engine and vehicle.
Implementation Method 1
The first sensor detects a first physical amount (for example, density of vaporized fuel) of a gas in a position at which the first sensor is provided
Implementation Method 2
The second sensor detects a second physical amount (for example, pressure of a gas containing the vaporized fuel) of a gas in a position at which the second sensor is provided
Data Source
AI summary
A leakage detecting device includes a first sensor, a second sensor, a pump, a leakage determination portion and a determination resetting portion. The first sensor, which is provided in a first passage connecting a fuel tank to a canister, detects density of vaporized fuel generated in the fuel tank. The second sensor, which is provided in a third passage connecting the canister to the pump, detects pressure in the third passage. The pump is provided between the third passage and an atmospheric passage. The leakage determination portion determines whether there is leakage in a vaporized fuel processing system or not, based on a time-variable amount of the pressure detected by the second sensor. The determination resetting portion resets a leakage determination result of the leakage determination portion, based on a time-variable amount of the density and the time-variable amount of the pressure.