Fuel Injector Rate Controller for Dynamic Injection Shaping
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Solution Overview
Problem
Common rail fuel systems face challenges in varying injection rate due to limitations in injection pressure responsiveness, resulting in a fixed square injection profile, which affects combustion efficiency and emissions, and existing solutions like precise control of outlet checks can undesirably impact spray characteristics.
Innovation Solution
The implementation of a fuel system with a common rail, fuel injectors featuring a high pressure inlet, nozzle chamber, control chamber, spray orifices, and an injection rate controller that adjusts the nozzle passage flow area between a rate limiting and a second configuration, allowing for variable injection rates by controlling the pressure drop through the nozzle passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If common rail fuel systems use fixed injection pressure control, then system simplicity is maintained, but injection rate cannot be varied dynamically affecting combustion efficiency and emissions
Solution Approach 1:
The patent applies dynamics by making the injection rate controllable through dynamic adjustment of the nozzle passage flow area. The injection rate controller varies the flow area between rate limiting and second configurations, allowing the system to adapt injection rates dynamically during engine operation rather than using a fixed injection profile, thereby resolving the contradiction between adaptability and complexity
Solution Approach 2:
The patent changes the physical parameter of flow area through the nozzle passage by introducing an injection rate controller that can adjust the flow area between different configurations. This parameter change enables dynamic injection rate control while maintaining the common rail system architecture, addressing the need for injection rate variability without fundamentally redesigning the entire fuel system
2Adaptability or versatility
If injection pressure is increased to improve injection rate control, then injection rate variability improves, but spray characteristics are adversely affected
Solution Approach 1:
The patent introduces an injection rate controller as an intermediary component between the high pressure inlet and the nozzle chamber. This intermediary device controls the flow area of the nozzle passage, allowing injection rate control without directly manipulating the outlet check or spray orifices, thereby avoiding adverse effects on spray characteristics while achieving injection rate variability
Solution Approach 2:
The patent segments the fuel flow control into two independent functions: (1) the outlet check controls injection timing and spray characteristics, and (2) the injection rate controller controls injection rate through nozzle passage flow area adjustment. This segmentation allows injection rate control to be achieved without affecting spray characteristics, resolving the contradiction between injection rate control and spray quality
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 solution enables dynamic control of fuel injection rates, improving combustion efficiency and reducing emissions by varying the injection rate profile, while minimizing adverse effects on spray characteristics.
Implementation Method 1
adjustable between a rate limiting configuration, and a second configuration. A flow area of the nozzle passage is limited by the injection rate controller to a relatively greater extent at the rate limiting configuration, and the flow area is limited to a relatively lesser extent at the second configuration to reduce a pressure drop from the high pressure inlet to the nozzle chamber during the injection of fuel.
Data Source
AI summary
A fuel system for an internal combustion engine includes a common rail and a plurality of fuel injectors connected to the common rail and each including an outlet check, an injection control valve, and an injection rate controller. The injection rate controller varies a flow area to a nozzle of the fuel injector such that a pressure drop through the fuel injector is varied to provide injection rate shaping.