Fuel Injector Control via Closing Electrical Decay
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Solution Overview
Problem
Internal combustion engine designs face challenges in accurately controlling fuel injector variability due to production process variations and aging, leading to performance deviations in fuel injection, which affect pollutant emissions and fuel economy.
Innovation Solution
A system and method that include a drive circuit and controller to output a drive signal with a pulse width, where the injection time is influenced by the pulse width and the closing electrical decay of the fuel injector, allowing the controller to determine and adapt the pulse width based on the closing electrical decay to control the injection time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed pulse width is used for fuel injection control, then the control system is simple, but fuel injection accuracy deteriorates due to injector variability
Solution Approach 1:
The system measures the actual closing time of the fuel injector by monitoring the electrical decay signal and uses this feedback to adjust the pulse width. The controller compares the measured closing time with expected values and adapts the pulse width accordingly, creating a closed-loop control system that compensates for injector variability without requiring complex hardware modifications.
Solution Approach 2:
The fuel injector's own electrical decay signal is used to determine its closing time characteristics. The system leverages the natural electrical behavior of the injector coil during closing to extract timing information, eliminating the need for external sensors or additional measurement devices on the injector itself.
2Manufacturing precision
If individual fuel injector corrections are implemented, then fuel injection accuracy improves, but measurement and control complexity increases
Solution Approach 1:
The system replaces mechanical or complex electrical measurement methods with electrical signal analysis. By monitoring the natural decay of the coil's electrical signal after pulse termination, the system extracts closing time information without requiring mechanical position sensors, Hall effect sensors, or complex optical measurement systems.
Solution Approach 2:
The electrical decay signal serves as an intermediary that indirectly provides information about the mechanical closing event. Instead of directly measuring the mechanical position of the injector valve, the system uses the electrical signal decay characteristics as a mediator to infer the closing time, simplifying the measurement approach.
3Manufacturing precision
If pulse width is adapted based on closing electrical decay, then fuel injection accuracy improves, but control algorithm complexity increases
Solution Approach 1:
The system performs preliminary measurement of the closing time characteristics during a calibration phase or initial operation. These pre-determined characteristics are stored and used to guide subsequent pulse width adjustments, avoiding the need for complex real-time calculations during actual fuel injection events.
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 effectively compensates for fuel injector variability, improving the accuracy of fuel injection, reducing performance deviations, and enhancing fuel economy and emission control by dynamically adjusting the pulse width based on the closing electrical decay.
Implementation Method 1
determine the closing electrical decay of the fuel injector by monitoring an injector signal
Data Source
AI summary
A system and method for controlling an injection time of a fuel injector. The system includes a drive circuit configured to output a drive signal having a pulse width, wherein the injection time is influenced by the pulse width and a closing electrical decay of the fuel injector. A controller is configured to determine the closing electrical decay of the fuel injector and adapt the pulse width based on the closing electrical decay to control the injection time. The closing electrical decay includes a closing response. The controller determines the closing response based on an injector signal, such as a coil voltage of the fuel injector. By determining the closing response, the pulse width can be adjusted to compensate for fuel injector part-to-part variability, fuel injector wear, variations in fuel pressure received by the fuel injector, dirt in the fuel injector, and the like.