Fuel Injection Valve Voltage Inflection Detection
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Solution Overview
Problem
Existing fuel injection control systems for internal combustion engines face challenges in accurately correcting variations in injection quantity due to valve lift amount variations in the partial lift region, leading to degraded exhaust emission and drivability.
Innovation Solution
A fuel injection control system that uses filtered voltages from low-pass filters with different cutoff frequencies to calculate the voltage inflection time, which correlates with valve-closing timing, allowing for accurate correction of injection pulses and reduction of noise influence through learning mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the unfiltered drive voltage is compared to the filtered reference voltage to detect armature position, then the detection method is simple, but the detection accuracy is poor due to noise influence
Solution Approach 1:
The patent segments the voltage signal processing into multiple stages: first filtering the drive voltage to remove noise, then detecting the armature position based on the filtered signal. This segmentation separates noise removal from position detection, resolving the contradiction between simple detection method and accurate measurement.
Solution Approach 2:
The patent introduces a filtered voltage signal as an intermediary between the raw drive voltage and the armature position detection. This intermediary signal removes noise influence while preserving the essential position information, enabling accurate detection without directly comparing noisy signals.
2Object-affected harmful factors
If a single low-pass filter is used to acquire terminal voltage, then the noise is reduced, but the response speed is slowed
Solution Approach 1:
The patent dynamically adjusts the filtering characteristics by using multiple low-pass filters with different time constants instead of a single fixed filter. This allows the system to balance noise reduction and response speed according to operating conditions, resolving the contradiction between reducing noise and maintaining response speed.
Solution Approach 2:
The patent changes the filtering parameters by employing multiple low-pass filters with different time constants (first and second time constants). This parameter variation allows optimal noise reduction while preserving necessary signal response characteristics, resolving the contradiction between noise reduction and response speed.
3Length of moving object
If the injection pulse width is increased to reach full lift position, then the valve lift is sufficient, but the injection quantity varies in partial lift region
Solution Approach 1:
The patent uses feedback from the detected armature position and voltage inflection timing to correct the injection pulse width. By continuously monitoring the valve element position and adjusting the injection pulse accordingly, the system maintains precise injection quantity control in the partial lift region while ensuring sufficient valve lift when needed.
Solution Approach 2:
The patent performs preliminary detection of the voltage inflection timing and armature position before finalizing the injection pulse correction. This preliminary action allows the system to predict and compensate for injection quantity variations in advance, improving precision in the partial lift region without compromising valve lift performance.
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 improves the accuracy of injection quantity control in the partial lift region, enhancing exhaust emission and drivability by accurately correcting injection quantity variations.
Implementation Method 1
acquires a first filtered voltage being a terminal voltage of the fuel injection valve filtered by a first low-pass filter having a first frequency as a cutoff frequency, the first frequency being lower than a frequency of a noise component, and acquires a second filtered voltage being the terminal voltage filtered by a second low-pass filter having a second frequency as a cutoff frequency
Implementation Method 2
a fuel injection control system of an internal combustion engine having an electromagnetic driving fuel injection valve
Data Source
AI summary
After off of an injection pulse of partial lift injection, a first filtered voltage Vsm1 being a negative terminal voltage of a fuel injection valve filtered by a first low-pass filter and a second filtered voltage Vsm2 being the negative terminal voltage of the fuel injection valve filtered by a second low-pass filter are calculated, and time from a predetermined reference timing to a timing when a difference Vdiff (=Vsm1−Vsm2) between the filtered voltages has an inflection point is calculated as voltage inflection time Tdiff. An averaged value Tdiff.ave of a predetermined frequency of data of the voltage inflection time Tdiff is obtained as a learning value of the voltage inflection time, and the injection pulse of the partial lift injection is corrected based on the learning value Tdiff.ave of the voltage inflection time.