Cryogenic Fuel Pump Accumulator Control for Low Load Efficiency
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Solution Overview
Problem
Cryogenic fuel systems for internal combustion engines face challenges in efficiently managing low engine fuel demands during low load and idle conditions, leading to either insufficient fuel supply or excessive fuel wastage, as high pressure cryogenic fuel pumps are not capable of operating below their minimum rated speed.
Innovation Solution
A method and control system that divert excess fuel to an accumulator during low demand conditions, stopping the primary pump when the accumulator reaches a predefined pressure limit, and supplying fuel from the accumulator to the engine as needed, optimizing fuel usage and preventing wastage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cryogenic fuel pump operates at minimum rated speed to meet low engine fuel demand, then the engine can be fueled during low load and idle conditions, but excess fuel is discharged and wasted requiring separation and return to storage tank
Solution Approach 1:
The accumulator stores excess fuel in advance during periods when the pump operates above minimum demand, so that fuel is available when the pump is stopped during low load and idle conditions. This preliminary storage action eliminates the need to waste and return excess fuel.
Solution Approach 2:
Instead of discarding (wasting and returning to tank) excess fuel, the system recovers it by storing in the accumulator during high demand periods, then reuses it during low demand periods when the pump is stopped.
2Loss of substance
If the cryogenic fuel pump is completely switched off to stop pumping excess fuel, then fuel wastage is eliminated, but the engine stops operating
Solution Approach 1:
The accumulator is pre-filled with fuel before the pump is switched off, ensuring continuous fuel supply to the engine during low load and idle conditions when the pump is stopped. This preliminary storage maintains engine operation continuity.
Solution Approach 2:
The accumulator acts as an intermediary between the fuel pump and the engine, providing a buffer that allows the pump to be stopped while still supplying fuel to the engine during low demand periods.
3Reliability
If the cryogenic fuel pump operates continuously at minimum rated speed, then fuel supply is maintained during low load and idle conditions, but excessive fuel is discharged requiring separation and return to tank
Solution Approach 1:
The fuel pump operates periodically - running at normal speed when demand is high to fill the accumulator, then stopping during low load and idle conditions. This periodic operation eliminates continuous fuel discharge and the associated energy waste from warming excess fuel.
Solution Approach 2:
The accumulator is pre-filled with fuel in advance during high demand periods, allowing the pump to stop during low demand periods without disrupting engine operation, thereby eliminating continuous operation and associated energy waste.
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 ensures efficient fuel supply during low load and idle conditions by storing excess fuel in an accumulator and reusing it when the primary pump is stopped, reducing wastage and maintaining engine operation without the need for continuous pump operation.
Implementation Method 1
storing excess fuel in an accumulator
Implementation Method 2
a liquefied gas is converted into gaseous form before being supplied to the engine
Data Source
AI summary
A method of operating a cryogenic fuel system for supplying fuel to an engine is provided herein. A cryogenic fuel pump is operated to pump fuel to be supplied to the engine. At least a portion of the pumped fuel is diverted to be supplied to an accumulator, when a fuel demand of the engine is less than a discharge output of the cryogenic fuel pump. Further, the supply of the pumped fuel from the cryogenic fuel pump to the engine and the accumulator is stopped, when a pressure within the accumulator reaches a first predefined pressure limit. Furthermore, the fuel is supplied to the engine from the accumulator, when supply of the pumped fuel from the cryogenic fuel pump to the engine and the accumulator is stopped.