Fuel Injector Calibration Using Opening Rate Slope Estimation
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Solution Overview
Problem
Current methods for estimating the injector opening rate shape slope in engine fuel injection systems are not robust, accurate, or computationally efficient, affecting combustion performance.
Innovation Solution
A system and method for calibrating and controlling fuel injectors using electronic control systems that determine injector opening rate shape slope by adjusting injector control parameters such as start of injection timing, rail pressure, and on-time, based on response surfaces and empirical calculations to match commanded fueling quantities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods are used to estimate injector opening rate shape slope, then the estimation process is simple, but the accuracy and robustness of combustion performance control deteriorates
Solution Approach 1:
The system uses feedback from actual injected quantity measurements (via rail pressure sensors) to iteratively adjust injector control parameters and refine the opening rate shape slope estimation, improving accuracy through continuous correction rather than single-pass estimation
Solution Approach 2:
The system performs preliminary calibration operations during engine commissioning to establish baseline injector characteristics and response surfaces, enabling more accurate real-time estimation without requiring complex computational resources during normal operation
2Measurement precision
If complex computational methods are used to improve estimation accuracy, then measurement precision improves, but computational efficiency and productivity deteriorates
Solution Approach 1:
Complex computational work is performed in advance during calibration to build lookup tables and response surfaces, transforming complex calculations into simple table lookups during real-time operation, thus achieving high accuracy without real-time computational burden
Solution Approach 2:
The system creates simplified mathematical models and response surfaces that replicate complex injector behavior, allowing accurate estimation through computationally efficient model evaluation rather than direct complex simulation
3Reliability
If real-time adjustment of multiple control parameters is implemented, then combustion performance and fuel economy improve, but control system complexity increases
Solution Approach 1:
The control system is segmented into independent modules: one for estimating opening rate shape slope, another for determining optimal control parameters via response surfaces, and a third for executing injections, allowing each to be optimized independently while maintaining overall system reliability
Solution Approach 2:
Response surfaces act as intermediaries between the estimated opening rate shape slope and the final control parameter selection, simplifying the control logic by pre-computing optimal parameter combinations rather than requiring real-time optimization algorithms
Data Source
AI summary
A method includes operating a fuel injector to perform a fuel injection, determining an estimate of the actual injected quantity of the fuel injection, determining a change in a commanded on time to achieve an injected quantity relative to the commanded on time required to initiate injection of the injector in response to the estimate of the actual injected quantity and a commanded injection quantity, and determining an injector opening rate shape slope estimate for the injector in response to the commanded on time required to initiate injection. The method may further include one or more of outputting a diagnostic or prognostic of the fuel injector, adjusting an injection control parameter, or adjusting an injector monitoring operation in response to the injector opening rate shape slope estimate.