Fuel Injection Control Device Inflexion Point Filtering
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Solution Overview
Problem
Variations in flow rate properties of fuel injection devices due to bouncing of the anchor with the core cause differences in fuel injection, which are influenced by the stroke length, making it challenging to estimate the set spring force accurately.
Innovation Solution
A control device for fuel injection systems that includes an inflexion point extraction filter to correct the drive current based on the timing of the later inflexion point, reducing the influence of stroke length and enabling precise estimation of the set spring force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If valve closure completion timing is used to estimate set spring force, then estimation can be performed, but stroke length causes disturbance and reduces estimation precision
Solution Approach 1:
The patent extracts and eliminates the disturbing factor (stroke length influence) from the estimation process. By using the time difference between the two inflexion points instead of the absolute timing, the method separates the spring force indication from the stroke length variation, achieving accurate estimation regardless of stroke differences.
Solution Approach 2:
The patent introduces an intermediary measurement approach - using the time difference between inflexion points as an intermediate parameter that correlates with spring force but is independent of stroke length. This intermediary metric serves as a reliable indicator that avoids the direct disturbance of stroke variation.
2Reliability
If anchor momentum is not adjusted according to set spring force, then device operation is simple, but bouncing occurs and flow rate variations increase
Solution Approach 1:
The patent implements a feedback mechanism where the estimated set spring force (derived from inflexion point timing) is used to adjust the drive current profile. This feedback loop ensures that the anchor momentum is appropriately matched to the spring force, reducing bouncing and improving flow rate consistency across different devices.
Solution Approach 2:
The patent changes the drive current parameters based on the estimated spring force characteristics. By adjusting current magnitude and pulse width according to the measured inflexion point timing, the system optimizes anchor acceleration to match the specific spring force of each device, eliminating bouncing variations.
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 approach allows for high-precision estimation of the set spring force, homogenizing the momentum of the rising anchor and valve element, thereby reducing variations in flow rate properties among individual fuel injection devices.
Implementation Method 1
an inflexion point extraction filter for filtering a drive voltage of a solenoid to extract inflexion points
Implementation Method 2
a drive control device of an electromagnetic valve for controlling a flow rate of fluid
Data Source
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AI summary
A set spring force is estimated with high precision and a drive waveform is corrected according to the results. A control device of a fuel injection device consists of an incorporation means of reading a drive voltage of a solenoid, an inflexion point extraction filter for filtering the drive voltage to highlight inflexion points, a means of selecting a later inflexion point or a means of calculating a temporal difference between a later inflexion point and an earlier inflexion point of the extracted inflexion points, and a drive current correction means of correcting a drive current parameter on the basis of timing of the selected, later inflexion point or a temporal difference between the inflexion points.