Fuel Injector Internal Filter Element for Clogging Prevention
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Solution Overview
Problem
Existing fuel injectors for common rail systems face limitations in adjusting injection timing and quantity due to mechanical dependencies on camshaft rotation, and are prone to clogging from high-pressure fuel contaminants, which can lead to reduced fuel efficiency and engine performance.
Innovation Solution
A fuel injector design featuring an energizer section with an electrical actuator, a nozzle check valve, and a control orifice manifold with an internal filter element to filter high-pressure fuel, allowing for precise control of injection events and protection against particulate clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel filters are disposed upstream of the common rail, then fuel cleanliness is improved, but the risk of control orifice clogging from remaining particulates increases
Solution Approach 1:
The patent implements a nested filtration system where an external fuel filter is disposed upstream of the common rail and an internal filter element is disposed within the fuel injector body, nesting the internal filter inside the injector to provide secondary filtration. This nested arrangement ensures that even if the external filter allows some particulates through, the internal filter provides an additional barrier specifically protecting the control orifices from clogging.
Solution Approach 2:
The internal filter element acts as an intermediary component between the incoming high-pressure fuel and the control orifices. It mediates the fuel flow by intercepting and removing particulates before the fuel reaches the vulnerable control orifices, thus protecting the precision components from direct exposure to contaminants.
2Manufacturing precision
If fuel injectors are machined to tight tolerances and robustly assembled, then injection precision is improved, but device complexity increases
Solution Approach 1:
The fuel injector is divided into distinct functional sections: the injector body containing the control orifices and internal filter, the nozzle assembly with precision nozzle orifices, and the actuator mechanism. This segmentation allows each section to be manufactured and assembled with appropriate tolerances for its specific function, reducing overall complexity while maintaining injection precision.
Solution Approach 2:
The internal filter element is designed to be self-contained within the injector body, requiring no external maintenance or replacement. It automatically performs its filtration function as fuel flows through the injector, and is designed to be replaced as a simple maintenance item rather than requiring complex disassembly of precision components.
3Productivity
If high pressure fuel is delivered to combustion chambers in multiple rapid injection events, then fuel efficiency is improved, but the risk of particulate clogging in control orifices increases
Solution Approach 1:
The internal filter element performs preliminary filtration of the high-pressure fuel before it reaches the control orifices. By removing particulates in advance, before the fuel enters the precision control passages, the system enables multiple rapid injection events to occur without risk of clogging the control orifices during these frequent injection cycles.
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
Enables flexible and efficient fuel injection with reduced risk of clogging, improving fuel efficiency and engine performance by using an electrical actuator for precise control and an internal filter to protect the control orifices from contaminants.
Implementation Method 1
an internal filter element is disposed proximately around the control orifice manifold. The internal filter element includes a plurality of filtration orifices arranged to filter high pressure fuel flowing between the high pressure inlet passage and the control orifice manifold
Implementation Method 2
the energizer section includes an electrical actuator such as a solenoid or piezoelectric element
Implementation Method 3
a nozzle check valve accommodated therein and configured to axially move with respect the injector axis to selectively seal and unseal a nozzle outlet
Implementation Method 4
a control orifice manifold in fluid communication with the high pressure inlet passage and the low pressure drain passage with a plurality of control orifices and a plurality of control passages associated with the plurality of control orifices which direct the flow of fuel through the fuel injector
Data Source
AI summary
A fuel injector for a common rail fuel system includes an energizer section, an injector section, and control section axially disposed along an injector axis. To control and injection event, the control section includes a control orifice manifold that has a plurality of control orifices and control passages to distribute high pressure fuel with the injector assembly. To prevent plugging of the control orifices and passages, an internal filter element with a plurality of filtration orifices is located in proximity to the control orifice manifold.