CNG Tank Leak Detection via Consumption and Pressure Analysis
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Solution Overview
Problem
Current methods for diagnosing leaks in compressed natural gas (CNG) delivery systems in vehicles are inadequate, as they fail to accurately detect leaks in a timely and efficient manner, which can lead to fuel wastage and reduced vehicle performance.
Innovation Solution
A method involving a controller that determines the initial and final amounts of CNG in the tank, calculates expected CNG consumption based on engine cycles, and compares this with actual consumption, while also measuring pressure differences and ambient temperature changes to detect leaks in the CNG delivery system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CNG consumption is monitored to detect leaks, then leak detection capability is improved, but measurement precision deteriorates due to variations in consumption caused by temperature fluctuations and engine cycles
Solution Approach 1:
The patent monitors multiple parameters including CNG consumption, temperature, pressure, and engine cycle information simultaneously. By observing how these parameters change together and comparing against expected relationships, the system can distinguish between consumption variations caused by normal operating conditions versus those caused by leaks, thereby resolving the measurement precision problem while maintaining leak detection capability
Solution Approach 2:
The system uses feedback from temperature sensors, pressure sensors, and engine cycle monitoring to continuously adjust and refine leak detection thresholds. By incorporating feedback about actual operating conditions, the system can dynamically adapt its detection criteria to maintain high measurement precision across varying temperatures and engine loads
2Reliability
If pressure measurements are used to detect leaks, then leak detection is improved, but measurement precision deteriorates due to temperature-induced pressure changes
Solution Approach 1:
The patent simultaneously monitors both pressure and temperature parameters and analyzes their relationship. Since pressure changes are expected to correlate with temperature changes according to gas laws, the system can identify when pressure variations exceed what would be expected from temperature alone, indicating a potential leak. This multi-parameter approach resolves the measurement precision issue by providing context for pressure readings
Solution Approach 2:
Temperature acts as an intermediary parameter that helps interpret pressure measurements. By using temperature as a reference point, the system can determine whether pressure changes are due to thermal expansion/contraction or actual gas loss, thereby improving measurement precision while maintaining reliable leak detection
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 method effectively identifies leaks by comparing actual and expected CNG consumption and pressure changes, enabling timely detection and notification of leaks, thus improving fuel efficiency and vehicle performance.
Implementation Method 1
determining a first CNG pressure measurement at a predetermined section in the CNG delivery system at a first time and obtaining a second CNG pressure measurement at the predetermined section
Implementation Method 2
determining an ambient temperature difference based on the first ambient temperature and the second ambient temperature
Data Source
AI summary
Methods and systems for detecting a leak in a compressed natural gas (CNG) delivery system of a vehicle are disclosed. According to some embodiments the method includes determining a first amount of CNG in a CNG tank of the vehicle, the first amount corresponding to a first time, and determining a second amount of CNG in the CNG tank at a second time, the second time being subsequent to the first time. The method further includes determining an expected CNG consumption of the vehicle during a period of time, the period of time beginning at the first time and ending at the second time. The method also includes determining an actual CNG consumption during the period of time based on the first amount of CNG and the second amount of CNG, and comparing the actual CNG consumption and the expected CNG consumption to determine whether a leak has occurred.