Fuel Injector Timing Correction via Split Injection
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Solution Overview
Problem
Advanced fuel injectors in spark ignited internal combustion engines exhibit unpredictable flow performances and significant variability, leading to deviations in fuel injection accuracy, particularly at low fuel injection quantities.
Innovation Solution
A method that involves splitting fuel injection events into a first low pulse and a complementary pulse to learn and correct injector opening and closing times, using these data to adjust pulse widths for precise fuel delivery, especially during low fuel injections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If advanced fuel injectors are used for stratified charge engines, then fuel economy is improved, but injection accuracy deteriorates due to unpredictable flow performances and significant variability between injectors
Solution Approach 1:
The system performs preliminary characterization of each injector during manufacturing or initial operation to determine its specific flow performance parameters and response times. This preliminary data is stored and used to pre-calculate corrected injection pulse widths, compensating for injector variability before actual fuel injection occurs.
Solution Approach 2:
The control system adjusts injection parameters (pulse width, timing) based on measured injector characteristics such as flow rate variations and response time delays. By changing these parameters dynamically according to each injector's actual performance, the system compensates for manufacturing tolerances and maintains accurate fuel delivery.
2Ease of operation
If injector response time is not compensated, then control simplicity is maintained, but injection precision deteriorates at low fuel quantities
Solution Approach 1:
The system pre-measures and stores the response time characteristics (opening delay, closing delay) of each injector during initialization or manufacturing. These pre-determined response time parameters are then used to automatically calculate corrected pulse widths without requiring real-time measurement during normal operation, maintaining control simplicity while improving precision.
3Manufacturing precision
If split fuel injection is implemented to learn injector timing, then low fuel injection accuracy is improved, but injection event complexity increases
Solution Approach 1:
The injection event is divided into multiple separate pulses (split injection) with distinct timing characteristics. By segmenting the injection into a first pulse and a second pulse, the system can independently measure and learn the opening and closing response times of the injector. This segmentation enables accurate characterization of injector dynamics that would be difficult to separate in a single continuous injection event.
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 enhances the accuracy of fuel injection control by minimizing variability and ensuring precise fuel delivery, even at low fuel quantities, by learning and applying correction values for injector timing, thereby improving engine efficiency and reducing emissions.
Implementation Method 1
with electromagnetic actuators a certain time period elapses between application of the command signal and the moment the actuator actually starts moving
Data Source
AI summary
A method of controlling fuel injection in an internal combustion engine having at least one cylinder with an associated fuel injector for performing injection events is proposed, wherein for each injection event a pulse width is determined with which the injector is kept open to spray a desired quantity of fuel. When the quantity of fuel of a given fuel injection event is greater than a learning threshold, a split fuel injection is performed, whereby a first, low injection pulse and a second, complementary injection pulse are executed. Data representative of a closing time and/or an opening time of the fuel injector is determined in respect of the first, low injection pulse and a learned correction value is elaborated based on the closing time and/or opening time, the learned correction value being subsequently used for injection control.