Fuel Injection Pressure Sensor Placement for State Detection
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Solution Overview
Problem
Conventional fuel injection devices, such as common-rail systems, can only accurately control injection quantity, but not other injection states like actual injection start point and maximum injection rate reach point, due to limitations in detecting pressure fluctuations near the nozzle holes, which affects engine combustion and torque output.
Innovation Solution
A fuel injection device with a pressure sensor located closer to the nozzle holes than the pressure-accumulation vessel, capable of detecting pressure fluctuations attributed to fuel injection, and a storage unit for individual difference information related to these fluctuations, allowing for precise control of injection states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is mounted in the common rail to detect fuel pressure, then the injection quantity can be controlled, but the injection states such as actual injection start point and maximum injection rate reach point cannot be accurately detected
Solution Approach 1:
A communication line is introduced as an intermediary medium between the common rail and nozzle holes. This communication line transmits pressure fluctuations from the common rail to the nozzle holes, enabling the pressure sensor to detect injection states indirectly through the pressure changes in the communication line, thereby achieving accurate detection without direct sensor placement near nozzle holes.
2Measurement precision
If the pressure sensor is located closer to the nozzle hole, then injection states can be detected with high accuracy, but the device structure becomes more complex
Solution Approach 1:
The communication line serves multiple functions: it is used for fuel distribution during normal operation and simultaneously acts as a sensing medium for pressure fluctuation detection. This multi-functionality allows the system to achieve accurate injection state detection without adding separate sensing structures, thereby avoiding increased device complexity.
3Measurement precision
If only Tq-Q characteristic is obtained through examination, then the examination process is simple, but injection states other than injection quantity cannot be controlled with high accuracy
Solution Approach 1:
The pressure sensor provides real-time feedback on pressure fluctuations during fuel injection. By analyzing the pressure fluctuation waveform characteristics, the system can determine injection states such as actual injection start point and maximum injection rate reach point. This feedback mechanism enables comprehensive injection characterization without requiring complex examination procedures.
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 high-accuracy control of injection states beyond injection quantity, improving engine combustion and torque output by accurately detecting and managing pressure fluctuations near the nozzle holes.
Implementation Method 1
a pressure sensor located in a fuel passage, which extends from the pressure-accumulation vessel to a nozzle hole of the fuel injection valve, and configured to detect pressure of the fuel
Data Source
AI summary
A fuel injection device includes a fuel injection valve for injecting fuel, which is distributed from a pressure-accumulation vessel. A pressure sensor is located in a fuel passage, which extends from the pressure-accumulation vessel to a nozzle hole, and configured to detect pressure of the fuel. The pressure sensor is located closer to the nozzle hole than the pressure-accumulation vessel. A storage unit stores individual difference information, which indicates an injection characteristic of the fuel injection valve, the injection characteristic being obtained by an examination. The individual difference information is related to a fluctuation pattern of a portion of the fluctuation in detected pressure waveform of the pressure sensor. The fluctuation is attributed to one fuel injection through the nozzle hole. The portion of the fluctuation is subsequent to an end of the fuel injection.