Fuel Injection Valve Branch Path for Pressure Sensor Accuracy
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Solution Overview
Problem
The existing methods for measuring fuel pressure changes in fuel injection valves for internal combustion engines, particularly those involving sensors installed in the joint between the common rail and high-pressure pipes, suffer from accuracy issues due to pressure attenuation within the high-pressure pipe and adverse effects from fuel flow.
Innovation Solution
A fuel injection valve design with a branch path diverging from the high-pressure path to deliver fuel directly to a pressure sensor, minimizing fuel flow and enhancing measurement accuracy, along with strategic placement and structural reinforcement to manage stress concentrations and improve installation flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fuel pressure sensor is installed in the joint between the common rail and high-pressure pipe, then the measurement position is accessible, but the measurement accuracy deteriorates due to pressure attenuation within the high-pressure pipe
Solution Approach 1:
The high-pressure fuel path is segmented into a main path for fuel delivery and a separate measurement path leading to the pressure sensor. This segmentation allows the sensor to be positioned in the measurement path where pressure attenuation is minimized, while the main path continues to function for fuel delivery to the injection valve.
Solution Approach 2:
A separate measurement path acts as an intermediary between the high-pressure fuel path and the pressure sensor. This intermediary path allows accurate pressure measurement to be taken from a location closer to the injection valve without requiring the sensor to be directly in the main fuel flow path, thus resolving the conflict between accessibility and measurement accuracy.
2Measurement precision
If the fuel pressure sensor is installed in the fuel injection valve, then the measurement accuracy of fuel pressure change is improved, but the measurement accuracy deteriorates due to adverse effects of fuel flow on the sensor
Solution Approach 1:
The fuel path is divided into a main high-pressure path for fuel delivery and a separate measurement path. The measurement path is designed to minimize fuel flow velocity and turbulence, creating a relatively quiescent environment for the pressure sensor while still capturing accurate pressure changes from the main path.
Solution Approach 2:
The measurement path serves as an intermediary that transmits pressure information from the high-pressure fuel path to the sensor without exposing the sensor to the full adverse effects of high-velocity fuel flow. The path design includes features that reduce flow disturbances while maintaining pressure signal fidelity.
3Measurement precision
If the pressure sensor is installed in the fuel injection valve, then the measurement accuracy is improved, but the device complexity and installation difficulty increase
Solution Approach 1:
The fuel injection valve body is designed with integrated multi-functionality, incorporating both the main fuel delivery path and the measurement path within a single structure. This allows the pressure sensor to be installed in the valve body without requiring separate external components or complex modifications to the fuel delivery system.
Solution Approach 2:
The measurement path is merged with the fuel injection valve structure rather than being a separate external component. This integration reduces overall device complexity by combining multiple functions (fuel delivery and pressure measurement) into a single unified structure, making installation more straightforward.
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 significantly improves the accuracy of fuel pressure measurement and allows for more flexible installation of the pressure sensor, reducing measurement errors and enhancing the reliability of fuel injection control.
Implementation Method 1
a fuel pressure sensor installed in the body to measure pressure of the high-pressure fuel which is changed by spraying of the fuel from the spray hole
Implementation Method 2
a branch path is formed in the body which diverges from the high-pressure path to deliver the high-pressure fuel to the fuel pressure sensor
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
It is equipped with an injector body 4z which has formed therein high-pressure paths 6az, 6bz, and 6cz through which high-pressure fuel flows to a spray hole and stores therein a piezo-actuator 2z (i.e., an opening/closing mechanism) and a back-pressure control mechanism 3z (i.e., an opening/closing mechanism) which open or close the spray hole, and a fuel pressure sensor 50z installed in the body 4z to measure the pressure of the high-pressure fuel. The body 4z has formed therein a branch path 6ez diverging from the high-pressure paths 6bz and 6cz to deliver the high-pressure fuel to the fuel pressure sensor 50z.