Orifice Characterization in Evaporative Leak Check Modules
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle leak detection systems often result in false positive leak identifications due to assuming a default orifice size, which can vary among different leak check modules, leading to incorrect diagnostics.
Innovation Solution
Incorporating a coded indication of the actual orifice size into a smart chip within the leak check module, allowing the controller to adjust the leak detection threshold based on the unique orifice size, ensuring only leaks of the default size and above are flagged during diagnostics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the controller assumes a default orifice size for leak detection, then the leak detection process is simple and fast, but false positive leak identifications occur due to orifice size variations
Solution Approach 1:
The orifice size information is pre-characterized and stored in a coded indication (smart chip) within the leak check module during manufacturing. Before leak detection begins, the controller retrieves this pre-stored orifice size information to configure the appropriate reference pressure threshold, eliminating the need for real-time measurement while ensuring accurate detection parameters are used from the start.
Solution Approach 2:
The system uses feedback by comparing the actual pressure differential during leak detection against a reference pressure that is adjusted based on the retrieved orifice size information. The controller continuously monitors the pressure sensor readings and compares them against the orifice-specific threshold to determine whether a leak condition exists, ensuring accurate detection tailored to each module's specific orifice characteristics.
2Device complexity
If the controller uses a fixed reference pressure for leak detection, then the detection process is simple, but it cannot accommodate variations in orifice size across different modules
Solution Approach 1:
The system changes the reference pressure parameter based on the retrieved orifice size information. Different orifice sizes correspond to different reference pressure values that are stored in the coded indication. When the controller retrieves the orifice size, it selects the appropriate reference pressure threshold from its memory, allowing the detection system to adapt to various orifice specifications while maintaining a relatively simple overall process.
3Measurement precision
If the coded indication of orifice size is stored in a smart chip, then accurate leak detection is achieved, but the device complexity increases
Solution Approach 1:
Instead of incorporating complex physical measurement devices or multiple sensors, the system uses a simple coded indication (smart chip) that contains digital information about the orifice size. This digital copy of the orifice characteristics allows the controller to accurately determine the appropriate detection parameters without adding mechanical or physical complexity to the leak check module itself.
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 reduces false positive leak identifications by accounting for the specific orifice size of each module, providing accurate leak diagnostics and reducing unnecessary maintenance actions.
Implementation Method 1
operating a pump to draw air from an emission control system through an orifice to obtain a reference pressure
Implementation Method 2
The pump may then be operated to generate decreasing pressure in the emission control system
Data Source
AI summary
Systems and methods for internal orifice characterization in an evaporative leak check module are disclosed. In one example approach, a method comprises operating a pump to draw air from an emission control system through an orifice to obtain a reference pressure, and indicating a leak in response to pressure in the emission control system remaining above a threshold pressure while operating the pump to decrease pressure in the emission control system, where the threshold pressure is based on a coded indication and the reference pressure.