Distributed Fuel Accumulators and Flow Limiters for Pressure Control
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Solution Overview
Problem
Common rail fuel systems are expensive and time-consuming to fabricate due to the use of heavy solid-stock materials and complex fabrication processes, and they lack effective mechanisms to limit fuel leakage during injector failure or dampen pressure oscillations.
Innovation Solution
A fuel system featuring simple, distributed accumulators and flow limiters, where each fuel injector is paired with a fuel accumulator located within a cylinder head, and flow limiters are placed between accumulators and injectors to restrict fuel flow during failures, using a design that reduces fabrication complexity and cost while controlling pressure oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a common rail made from heavy solid-stock material is used to withstand high fuel pressure, then the system can handle elevated pressures reliably, but the fabrication cost and time increase due to complex gun-drilling and cross-drilling processes
Solution Approach 1:
The common rail is divided into multiple separate accumulator chambers, each serving a specific injector. This segmentation allows each accumulator to be manufactured independently using simpler processes, eliminating the need for complex gun-drilling and cross-drilling of a single solid-stock common rail, while still maintaining the ability to withstand high fuel pressures through distributed pressure management
Solution Approach 2:
Accumulators are introduced as intermediary components between the fuel pump and injectors. These accumulators serve as pressure buffers that decouple the high-pressure fuel supply from the injectors, allowing the common rail to be constructed with simpler fabrication processes while maintaining system pressure requirements through the accumulator chambers
2Quantity of substance
If multiple chambers are included within each pressure accumulator, then fuel storage capacity increases, but the complexity of the accumulators increases making them expensive and time-consuming to fabricate
Solution Approach 1:
Multiple accumulator chambers are merged into a single integrated accumulator body for each injector. Instead of creating separate multi-chamber structures that would require complex fabrication, the invention combines the storage function into one chamber while using the accumulator's positioning and connection system to manage fuel distribution, thereby maintaining fuel storage capacity while significantly reducing fabrication complexity
Solution Approach 2:
The single-chamber accumulator is designed to perform multiple functions: fuel storage, pressure regulation, and flow management. By making the accumulator multi-functional, the need for multiple separate chambers is eliminated, reducing fabrication complexity while still achieving the required fuel storage capacity through optimized single-chamber geometry and strategic positioning
3Productivity
If flow limiters are not installed, then the system allows free fuel flow during normal operation, but fuel leakage increases during catastrophic injector failure and pressure oscillations increase
Solution Approach 1:
The flow limiter incorporates a movable valve element that dynamically adjusts the flow restriction based on operating conditions. During normal operation, the valve remains open to allow free fuel flow and maintain productivity. During catastrophic injector failure, the pressure differential causes the valve to move and restrict flow, preventing fuel leakage and stabilizing system pressure
Solution Approach 2:
The flow limiter changes the flow resistance parameter dynamically. Under normal conditions, the flow resistance is low to maintain high fuel flow rates. When injector failure occurs, the pressure change triggers a parameter shift where the flow resistance increases significantly, limiting fuel leakage and dampening pressure oscillations without affecting normal operation
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 reduces fabrication costs and time, effectively inhibits fuel leakage during injector failures, and dampens pressure oscillations, improving overall system efficiency and reliability.
Implementation Method 1
a spring disposed within the recess and biased against the first valve element
Implementation Method 2
to dampen pressure oscillations caused by normal operation of the fuel injector
Implementation Method 3
a fuel accumulator associated with each of the plurality of fuel injectors. Each of the plurality of fuel accumulators may be disposed at least partially within a different cylinder head of the engine in fluid communication with an associated fuel injector
Data Source
AI summary
A fuel system for an engine is disclosed. The fuel system may have a pump, a plurality of fuel injectors, and a plurality of fuel accumulators. Each of the plurality of fuel accumulators may be disposed at least partially within a different cylinder head of the engine in fluid communication with an associated fuel injector of the plurality of fuel injectors. Each of the plurality of fuel accumulators may also be in fluid communication with adjacent fuel accumulators of the plurality of fuel accumulators. At least one of the plurality of fuel accumulators may also be in fluid communication with the pump. The fuel system may further have a plurality of flow limiters. Each of the plurality of flow limiters may be disposed between an associated fuel accumulator of the plurality of fuel accumulators and an associated fuel injector of the plurality of fuel injectors.