LNG Tank Pressure Control via Engine Fuel Consumption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquefied natural gas (LNG) storage tanks in rail vehicles experience pressure buildup due to inefficient insulation and refrigeration, leading to venting, which wastes fuel and releases pollutants, as the pressure relief valve opens to maintain safety thresholds.
Innovation Solution
A method is implemented where a controller sends a fuel request to the fuel tender to reduce gaseous fuel pressure by adjusting vehicle operating parameters, such as engine speed and vaporizer operation, to consume remaining fuel before the vehicle enters an inactive state, thereby reducing tank pressure without venting, by gradually ramping down the conversion of liquid to gaseous fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure relief valve opens to maintain safety thresholds, then safety is improved, but fuel is wasted and pollutants are released
Solution Approach 1:
The system performs preliminary action by consuming remaining gaseous fuel through the engine before entering inactive state or before pressure relief is needed. The controller proactively manages fuel consumption to prevent pressure buildup, rather than reactively venting when pressure thresholds are reached.
Solution Approach 2:
The system converts the potentially harmful high-pressure condition into a benefit by using the pressure differential to drive fuel consumption through the engine. The pressure that would otherwise require venting is instead utilized to push remaining fuel through the vaporizer and into the engine for combustion.
2Reliability
If the pressure relief valve opens to maintain safety thresholds, then safety is improved, but pollutants are released into the environment
Solution Approach 1:
The controller proactively consumes remaining gaseous fuel through the engine before pressure relief is needed, preventing pollutant release. This preliminary fuel consumption action occurs during active operation when the engine can properly combust and treat the fuel, rather than allowing it to be vented uncombusted.
Solution Approach 2:
The system converts the potential pollutant release into a benefit by channeling the pressurized gaseous fuel through the engine for complete combustion. The fuel that would otherwise be released as a pollutant is instead burned efficiently, converting it into less harmful exhaust products.
3Quantity of substance
If the vaporizer continues converting liquid fuel to gaseous fuel during inactive periods, then fuel availability is maintained, but tank pressure builds up requiring venting
Solution Approach 1:
The system dynamically adjusts vaporizer operation based on real-time conditions. During inactive periods or when approaching stopping locations, the controller reduces or stops vaporizer operation to prevent pressure buildup. The system transitions from a static continuous operation mode to a dynamic variable operation mode that responds to operational needs.
Solution Approach 2:
The controller uses feedback from pressure sensors and operational status to regulate vaporizer operation. When tank pressure approaches thresholds or when the vehicle is approaching a stopping location, the controller receives feedback and adjusts vaporizer output accordingly, reducing conversion of liquid to gaseous fuel to prevent unnecessary venting.
4Power
If the engine consumes fuel at normal operating parameters, then power output is maintained, but remaining fuel is not consumed before inactive state
Solution Approach 1:
The system performs preliminary fuel consumption by adjusting engine parameters to consume remaining gaseous fuel before entering inactive state. The controller proactively increases fuel consumption rate during the approach to stopping location, ensuring remaining fuel is utilized before pressure relief becomes necessary.
Solution Approach 2:
The system changes engine operating parameters to optimize fuel consumption. The controller adjusts parameters such as fuel injection timing, air-fuel ratio, or engine speed to maximize the consumption of remaining gaseous fuel from the tank, transforming standard operating parameters into optimized consumption parameters.
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 pollutant release and increases fuel economy by minimizing venting events and optimizing fuel consumption, especially when approaching a stopping location or during periods of reduced activity.
Implementation Method 1
Prior to injection into a locomotive's natural gas-fueled engine, LNG is typically vaporized into gaseous natural gas (CNG)
Implementation Method 2
when the LNG storage tank pressure increases above a threshold pressure, vapor within the LNG tank may be preferentially routed to a vaporizer
Data Source
AI summary
Various methods and systems are provided for initiating and executing a fuel routine for a vehicle. In one embodiment, a method comprises sending from a controller of a vehicle a fuel request to a fuel tender to reduce a pressure of gaseous fuel on the fuel tender and adjusting one or more vehicle operating parameters to allow consumption of the gaseous fuel at an engine of the vehicle when the pressure of the gaseous fuel is below a threshold supply pressure.