LNG Fuel Level Measurement via ECM Pressure Analysis
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Solution Overview
Problem
Existing fuel level measurement systems for LNG-powered machines face challenges due to the difficulty in troubleshooting and repairing integrated sensors within the thermally insulated fuel tank, which can compromise thermal insulation and increase complexity and cost, especially when additional sensors like flow meters are introduced.
Innovation Solution
An engine control module (ECM) is used to determine the fuel level in the tank by analyzing pressure changes and operator signals, eliminating the need for flow meters and reducing the complexity of the fuel delivery system, while maintaining accurate fuel level indication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fuel level measurement sensors are integrated into the fuel tank, then fuel level measurement is achieved, but troubleshooting and repair becomes difficult and thermal insulation is compromised
Solution Approach 1:
The patent extracts the fuel level measurement function from the integrated sensor system and relocates it to the ECM through software-based calculation. Instead of having physical sensors inside the fuel tank, the system uses the ECM to calculate fuel level by integrating fuel consumption data from mass flow commands and operator signals, effectively removing the measurement function from the difficult-to-access location while maintaining measurement capability.
Solution Approach 2:
The patent replaces the mechanical/electrical sensor system with a software-based calculation system in the ECM. The fuel level measurement is achieved through computational methods using fuel consumption data rather than physical sensors, substituting a mechanical measurement approach with an electronic/software-based approach that eliminates the need for intrusive tank integration.
2Measurement precision
If additional sensors like flow meters are introduced to measure LNG level, then measurement capability is improved, but system complexity and cost increase
Solution Approach 1:
The patent makes the ECM perform multiple functions: it not only controls engine operation based on operator signals but also calculates fuel level measurement. By integrating the measurement function into the existing ECM that already processes mass flow commands and operator inputs, the system achieves multi-functionality without adding separate measurement devices, thereby reducing overall system complexity.
Solution Approach 2:
The system uses its own operational data (mass flow commands and operator signals) to self-determine fuel level. The ECM leverages data it already collects for engine control purposes to simultaneously perform fuel level measurement, making the system self-sufficient without requiring external measurement instruments.
3Loss of information
If wired fuel level measurement sensors are used, then fuel level can be displayed, but thermal leakage increases due to thermal routes
Solution Approach 1:
The patent removes the physical sensing elements from the cryogenic fuel tank environment. By calculating fuel level through software integration of consumption data in the ECM (which is outside the tank), the system eliminates the thermal conduction path that would exist with wired sensors penetrating the tank wall, thereby preventing thermal leakage while maintaining fuel level indication.
Data Source
AI summary
A fuel level measurement system and method for liquified natural gas (LNG) powered machines is disclosed. An engine control module (ECM) receives fuel line pressure levels at a first time (e.g., a key-off event) and, again, at a second time (e.g., a key-on event). The ECM predicts an expected change in pressure from the key-off event to the key-on event based on various factors. If the change in pressure detected is greater than a threshold level different from the predicted change in pressure, the ECM determines a fill event and resets a current fuel level. The ECM tracks mass flow commands used to provide fuel to the engine to determine the consumption of fuel from the fuel tank and to determine a new current fuel level based on the amount of fuel consumed. The current fuel level is displayed on a fuel gauge.