Fuel Rail Narrowed Conduit Pressure Sensor Placement
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Solution Overview
Problem
Current fuel injection systems face challenges in achieving precise control of low injection quantities due to limitations in sensor accuracy and the need for additional pressure sensors, leading to increased complexity and cost, especially for pilot injections.
Innovation Solution
A fuel system design with a common rail featuring a narrowed section for fuel injectors, where a single pressure sensor is located within this narrowed conduit, allowing for accurate detection of injection duration and pressure drop without requiring additional sensors, thereby improving precision and reducing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pressure sensor is used in the common rail, then system complexity is reduced, but measurement precision of injection quantity is insufficient for low injection quantities
Solution Approach 1:
The common rail is segmented into a first flow path (main rail) and a second flow path (narrowed conduit), with the pressure sensor specifically positioned in the second portion. This segmentation allows the sensor to detect pressure changes with higher sensitivity for low injection quantities while maintaining system-wide pressure monitoring capabilities.
Solution Approach 2:
The second portion of the flow path is designed with a narrower cross-section than the first portion, creating a localized region of higher flow velocity and pressure sensitivity. The pressure sensor is strategically placed in this narrowed section to maximize detection accuracy for injection events, particularly for low quantity injections.
2Measurement precision
If additional pressure sensors are integrated in individual injectors or fuel passage pipes, then measurement precision of injection quantity is improved, but device complexity and system cost increase
Solution Approach 1:
The invention merges the functions of multiple pressure sensors into a single pressure sensor located in the narrowed second portion of the common rail. This single sensor can detect pressure changes for multiple injectors simultaneously, eliminating the need for individual sensors at each injector while maintaining measurement precision.
Solution Approach 2:
The pressure sensor in the narrowed conduit serves multiple functions: it monitors overall rail pressure, detects individual injection events, measures injection duration, and determines injection quantity. This multi-functionality replaces what would otherwise require multiple dedicated sensors.
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 design enhances the accuracy of injection quantity control by utilizing a single rail pressure sensor to detect injection start and end points and pressure waves, correlating well with actual injection durations and quantities, while maintaining technological simplicity and cost-effectiveness.
Implementation Method 1
A pressure sensor located in or adjacent to the conduit detects pressure waves and measures the injection duration and fuel pressure drop
Implementation Method 2
This method is based on the principle of fuel compressibility. The injection quantity, namely the quantity released from a closed system with a constant volume, is proportional to the system pressure drop
Data Source
AI summary
An arrangement for supplying high pressure fuel to a plurality of fuel injectors includes a housing defining a fuel chamber. The chamber is provided with a flow inlet from a high pressure fuel source and forms a first portion of flow path of the fuel, the chamber being fluidly connected to a conduit providing a second portion of flow path. The conduit has a plurality of outlets adapted to provide flow of high pressure fuel from the chamber via the conduit to a corresponding plurality of injectors via respective first outlet flow conduits. The second portion of flow path is substantially narrower than the first flow path, and includes a pressure sensor located in or adjacent to the conduit.