Fuel Injector Reference Current Determination
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Solution Overview
Problem
Fuel injectors with solenoid drives exhibit varying opening and closing behaviors due to electrical, magnetic, mechanical, and hydraulic tolerances, leading to inconsistent injection quantities, which become significant as injection times shorten, and laboratory measurements are costly and unable to account for in-service changes.
Innovation Solution
A method involving applying a first voltage pulse to open the fuel injector, followed by a holding voltage, then briefly switching off the voltage to determine the temporal progression of the current intensity with a second pulse, which constitutes the reference current progression, allowing precise determination of the injector's opening state and adaptation of the injection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laboratory measurements are performed to determine reference current progressions, then measurement precision is improved, but cost increases and the measurements cannot account for in-service changes
Solution Approach 1:
The patent creates a virtual copy of the laboratory measurement process by generating reference current progressions through simulated solenoid drive behavior based on manufacturer data. This allows the system to obtain precise reference data without performing actual laboratory measurements, thereby reducing cost while maintaining measurement precision.
Solution Approach 2:
The system performs self-calibration by automatically generating and updating reference current progressions during normal operation using the solenoid drive's own characteristics and manufacturer-provided data. This eliminates the need for external laboratory measurements while maintaining accurate reference data for comparison.
2Productivity
If injection time is reduced to increase productivity, then fuel injection efficiency is improved, but relative quantitative differences between injectors become more significant
Solution Approach 1:
The patent implements a feedback mechanism that continuously compares the actual current progression of each injector against its reference current progression. Based on this comparison, the system detects deviations in opening and closing behavior and compensates for them by adjusting injection parameters, thereby maintaining consistent injection quantities even at reduced injection times.
Solution Approach 2:
The system dynamically adjusts injection parameters such as voltage pulse duration and amplitude based on the detected current progression characteristics of each injector. By changing these parameters in real-time, the system compensates for individual injector variations and maintains precise injection quantities despite shorter injection durations.
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 method effectively compensates for relative injection quantity differences, providing precise and cost-effective determination of the fuel injector's opening state, enabling precise adaptation of the injection process to minimize deviations and maintain consistent fuel injection.
Implementation Method 1
fuel injector has a solenoid drive
Implementation Method 2
applying a first voltage pulse to the solenoid drive of the fuel injector, so that the fuel injector is opened
Implementation Method 3
The temporal progression of the current intensity during a process for opening the fuel injector (in which a voltage pulse (boost voltage) is applied to the solenoid drive) is dependent on the inductance of the solenoid drive. In addition to the changing self-inductance of the solenoid drive
Implementation Method 4
there is also a component of motional inductance by reason of the motion of the armature. The component of motional inductance begins with the beginning of the opening phase (armature/needle motion begins), and ends at the end of the opening phase
Data Source
AI summary
A method for determining a reference current curve for a fuel injector having a magnetic coil drive in an internal combustion engine of a motor vehicle includes: (a) applying a first voltage pulse to the magnetic coil drive to open the fuel injector, (b) applying a holding voltage to the magnetic coil drive to hold the fuel injector open, (c) switching off the holding voltage, (d) waiting for substantially no current to flow through the magnetic coil drive for a predetermined time period that is sufficiently short that the fuel injector remains open, (e) applying a second voltage pulse to the magnetic coil drive, and (f) recording a time-based curve of the current that flows through the magnetic coil drive during the second voltage pulse, which forms the reference current curve. This reference current curve is used for determining a time of a predetermined opening state of the fuel injector.