Fuel Injection Valve Closing Time Detection via Back-EMF Differential Analysis
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Solution Overview
Problem
Existing electromagnetic valve driving devices face challenges in reliably detecting the valve closing inflection point due to the presence of secondary inflection points in the differential waveform of counter electromotive voltage, making it difficult to accurately control the fuel injection valve's closing time.
Innovation Solution
A control device that includes a voltage detection unit, differential calculation unit, storage unit, maximum detection unit, and valve closing time detection unit, which scans the differential value in a time-series order and retrospectively traces the data to detect the valve closing inflection point by identifying a maximum point where the decrease exceeds a predetermined threshold value, ensuring accurate detection of the valve closing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional method of detecting the maximum value in the differential waveform is used, then the detection process is simple, but the valve closing inflection point cannot be reliably detected due to the presence of secondary inflection points
Solution Approach 1:
The detection process is divided into multiple sequential steps: (1) detecting the maximum value point in the differential waveform, (2) calculating the decrease amount from this maximum value, (3) comparing the decrease amount with a threshold, and (4) determining the valve closing inflection point based on these comparisons. This segmentation allows reliable detection by systematically filtering out secondary inflection points while maintaining a clear and structured detection流程.
2Measurement precision
If the threshold value for detecting the valve closing inflection point is set low, then more inflection points can be detected, but secondary inflection points may be mistakenly identified as the valve closing point
Solution Approach 1:
The detection method uses feedback by comparing the decrease amount from the maximum value with a predetermined threshold. This feedback mechanism allows the system to verify whether a detected inflection point is genuine (valve closing) or spurious (secondary inflection point), thereby improving detection accuracy while maintaining reliability.
3Reliability
If the threshold value for detecting the valve closing inflection point is set high, then false detections are reduced, but the valve closing inflection point may be missed
Solution Approach 1:
The method dynamically adjusts the detection parameters by first identifying the maximum value in the differential waveform and then using this maximum value as a reference point for subsequent threshold comparisons. This parameter change approach ensures that the threshold is applied relative to the actual signal characteristics, preventing both false positives and false negatives in inflection point detection.
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 solution allows for reliable detection of the valve closing inflection point, enabling precise control of the fuel injection valve's closing time and improving the consistency of fuel injection, thereby enhancing the performance of the electromagnetic valve driving device.
Implementation Method 1
a counter electromotive voltage generated in the solenoid coil
Data Source
AI summary
An electromagnetic valve driving device includes: a maximum detection unit configured to detect a maximum point when time-series data of a differential value of a counter electromotive voltage generated in a solenoid has changed from an increase to a decrease by retrospectively tracing the time-series data in an opposite direction of a time series; and a valve closing time detection unit configured to execute a determination process of retrospectively tracing the time-series data from the maximum point detected by the maximum detection unit in the opposite direction and scanning whether or not an amount of decrease in the differential value from the maximum point exceeds a predetermined threshold value and detect a maximum time, which is a time of the maximum point, as a valve closing time of a fuel injection valve when there is an event in which the amount of decrease exceeds the predetermined threshold value.