Self-tuning Fuel Injection System with Discontinuity Checks
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Solution Overview
Problem
Existing fuel injection systems face discontinuities in look-up tables during long-term fuel trim corrections, leading to suboptimal performance under varying engine conditions, particularly during wide-open throttle conditions and engine startup.
Innovation Solution
A self-tuning electronic fuel injection system that uses a computer processor to execute algorithms for fuel injector pulsing, incorporating an airflow estimator and fuel pulse generation algorithm, along with a long-term fuel trim correction algorithm that checks for potential discontinuities in the look-up tables using mathematical checks, and a repair algorithm to smooth out data for optimal air/fuel ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If long-term fuel trim corrections are applied to look-up tables, then fuel control accuracy is improved, but discontinuities in the look-up tables occur leading to suboptimal performance
Solution Approach 1:
The patent applies preliminary anti-action by checking for potential discontinuities in the look-up tables before applying long-term fuel trim corrections. The system evaluates whether corrections would create discontinuities and prevents their application, thereby avoiding the harmful effect of performance inconsistency while maintaining fuel control accuracy through alternative correction methods.
2Measurement precision
If closed-loop control is used for fuel injection, then air-fuel ratio accuracy is improved, but feedback lag time occurs reducing responsiveness
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing fuel trim corrections in look-up tables based on engine operating conditions. This allows the system to apply corrections proactively before actual fuel injection events, reducing feedback lag time while maintaining air-fuel ratio accuracy through pre-computed correction values that are applied during both open-loop and closed-loop control modes.
3Reliability
If look-up tables are updated with long-term corrections, then overall fuel control is improved, but discontinuities affect both open-loop and closed-loop control modes
Solution Approach 1:
The patent applies preliminary anti-action by implementing a discontinuity check mechanism that evaluates potential look-up table corrections before applying them. The system identifies conditions that would create discontinuities and prevents their application, thereby maintaining look-up table continuity and stability across both open-loop and closed-loop control modes while still achieving overall fuel control improvement through safe corrections.
Data Source
AI summary
A self-tuning fuel injection system and method having a first long-term fuel trim correction algorithm to selectively replace an operating zone within a volumetric efficiency look-up table based with a proposed correction only if mathematical comparisons with a surrounding determinative zone reveal that the correction will not result in an abrupt discontinuity. Mathematical comparison models may include absolute values of the differences or percent differences of each proposed cell and its neighbors, the difference of each proposed cell and the mean of its eight neighbors, and standard deviation of each proposed cell and its neighbors. A second repair algorithm repairs values surrounding an operating zone that have such a dissimilar magnitude as to cause poor engine performance using linear interpolation, for example. According to the invention, either the correction or the repair algorithm, or both, are executed in series or in parallel.