LNG Fuel Delivery System Temperature Control
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Solution Overview
Problem
Engines using Liquefied Natural Gas (LNG) face reduced performance due to pressure drops in the LNG tank during refueling and operation, leading to inadequate fuel supply pressure below the specified threshold.
Innovation Solution
A fuel delivery system with a temperature sensor, heat exchanger, valves, and an accumulator that selectively bypasses fuel to raise the tank's temperature and pressure, eliminating the need for an additional boost pump by using a controller to manage the flow and conversion of LNG to vaporized natural gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If LNG is stored in a tank at low temperature, then fuel storage capacity is improved, but pressure within the tank reduces leading to inadequate fuel supply pressure
Solution Approach 1:
The system changes the temperature parameter of the LNG by introducing warmer ambient air into the tank through the return conduit. This temperature increase raises the vapor pressure of the LNG, thereby improving the fuel supply pressure to the engine without compromising storage capacity
Solution Approach 2:
The return conduit acts as an intermediary channel that introduces ambient air (a warmer substance) into the LNG tank. This intermediary substance transfers thermal energy to the LNG, raising its temperature and pressure, and subsequently the warmed air is exhausted through the delivery conduit
2Stress or pressure
If ambient air is introduced to raise fuel temperature, then pressure is improved, but system complexity increases with additional conduits and control mechanisms
Solution Approach 1:
The return conduit serves multiple functions: it provides a return path for vaporized fuel to the tank, introduces ambient air to warm the LNG and raise pressure, and acts as a pathway for the control system to regulate fuel flow. This multi-functionality reduces the need for separate components, thereby limiting the increase in system complexity
Solution Approach 2:
The system utilizes ambient air (a freely available resource) to warm the LNG and raise tank pressure, rather than requiring an external heating system or compressor. The natural temperature difference between ambient air and cold LNG provides the necessary thermal energy, making the system self-sufficient and reducing complexity
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 system effectively maintains adequate pressure in the LNG tank and ensures consistent fuel supply to the engine, enhancing performance without requiring additional pressure management equipment, thus reducing system complexity and cost.
Implementation Method 1
The accumulator is adapted to convert the portion of the fuel from a liquid state to a gaseous state. The portion of the fuel is adapted to raise the temperature of the fuel present within the tank.
Implementation Method 2
The system includes a heat exchanger coupled to the delivery conduit downstream of the tank.
Implementation Method 3
The temperature sensor is configured to generate a signal indicative of a temperature of the fuel present within the tank.
Data Source
AI summary
A fuel delivery system for an engine is provided. The fuel delivery system includes a tank, a temperature sensor, a delivery conduit, a return conduit, a heat exchanger, a first valve, a second valve, an accumulator, and a controller. The controller is configured to receive a signal indicative of a temperature of a fuel present within the tank. The controller is also configured to control at least one of the first valve and the second valve to selectively bypass at least a portion of the fuel to the tank through the return conduit and the accumulator based, at least in part, on the received signal. The portion of the fuel is adapted to raise the temperature of the fuel present within the tank.