Fuel Injection Control System Voltage Inflection Correction
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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 variations in lift amount in the partial lift region, leading to degraded exhaust emission and drivability.
Innovation Solution
A fuel injection control system that uses filtered-voltage acquisition, difference calculation, and time calculation to determine the voltage inflection time, which is then used to correct the injection pulse, thereby improving the accuracy of injection quantity control in the partial lift region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the unfiltered drive voltage UM (raw value) is compared to the filtered reference voltage UR to detect the armature position, then the detection method is simple, but the intersection cannot be accurately detected due to noise influence
Solution Approach 1:
The patent divides the voltage signal processing into multiple stages: first filtering the drive voltage UM through a low-pass filter to obtain filtered drive voltage, then comparing it with the reference voltage UR. This segmentation of the detection process allows noise removal while maintaining accurate intersection detection, resolving the contradiction between simple detection methods and accurate measurement.
2Quantity of substance
If the injection pulse width is short to achieve partial lift injection, then the injection quantity is reduced, but the lift amount varies greatly leading to large variation in injection quantity
Solution Approach 1:
The patent implements feedback control by detecting the actual armature position through voltage intersection detection and using this information to correct the injection pulse width. The system continuously monitors the lift amount via voltage signals and adjusts the injection quantity accordingly, ensuring accurate control even in the partial lift region where traditional methods fail.
Solution Approach 2:
The patent changes the parameter being monitored from direct mechanical lift measurement to electrical voltage intersection detection. By transforming the physical measurement problem into an electrical signal processing problem, the system achieves accurate lift amount detection in the partial lift region, thereby improving injection quantity control accuracy.
3Ease of operation
If the intersection of drive voltage UM and reference voltage UR is used to detect armature position, then the detection method is straightforward, but the intersection may not exist depending on solenoid characteristics
Solution Approach 1:
The patent applies preliminary filtering to the drive voltage UM before comparison with the reference voltage UR. This pre-processing step ensures that the filtered drive voltage has the necessary characteristics to intersect with the reference voltage, guaranteeing the existence of the intersection point while maintaining the simplicity of the detection method.
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
The system accurately corrects the variation in injection quantity, enhancing control accuracy and reducing the impact of noise and noise-induced errors, leading to improved exhaust emission and drivability.
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
Implementation Method 2
acquires a second filtered voltage being the terminal voltage filtered by a second low-pass filter having a second frequency as a cutoff frequency, the second frequency being lower than the first frequency
Implementation Method 3
an electromagnetic driving fuel injection valve that calculates a required injection quantity in correspondence to an operation state of the internal combustion engine, and drives the fuel injection valve to open with an injection pulse
Data Source
AI summary
At least after off of an injection pulse of partial lift injection, a first filtered voltage Vsm1 being a negative terminal voltage Vm of a fuel injection valve filtered by a first low-pass filter having a first frequency f1 as a cutoff frequency, the first frequency f1 being lower than a frequency of a noise component, is acquired, and a second filtered voltage Vsm2 being the negative terminal voltage Vm filtered by a second low-pass filter having a second frequency f2 as a cutoff frequency, the second frequency f2 being lower than the first frequency f1, is acquired. 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, and the injection pulse of the partial lift injection is corrected based on the voltage inflection time Tdiff.