Self-tuning electronic fuel injection system

摘要

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.

主权项

1. A control system for a fuel-injected internal combustion engine, comprising:
a computer processor; a memory operatively coupled to said computer processor; data stored in said memory, said data including a plurality of numerical values approximately proportional to volumetric efficiency of said engine at a plurality of discrete engine speeds and a plurality of discrete engine loads, each of said numerical values being associated with one of said plurality of discrete engine speeds and one of said plurality of discrete engine loads; electronic circuitry connected to said computer processor for coupling said computer processor to an engine load sensor, an engine speed sensor, an exhaust sensor, and a fuel injector; a first algorithm stored in said memory and structured for execution by said computer processor to determine an engine speed from said engine speed sensor and an engine load from said engine load sensor and, based on said data and a target air-fuel ratio, to generate an output signal so as to cause said fuel injector to introduce fuel to said engine at an appropriate flow rate for said engine speed and said engine load; a second algorithm stored in said memory and structured for execution by said computer processor to compare said target air-fuel ratio to an actual air-fuel ratio that is determined using said exhaust sensor and, if said actual air-fuel ratio differs from said target air-fuel ratio by more than a predetermined amount, to propose a corrected value to be used in place of a first of said plurality of numerical values; and a third algorithm stored in said memory and structured for execution by said computer processor, said third algorithm being one from the group consisting of a correction algorithm and a repair algorithm; wherein said correction algorithm is structured to replace said first of said plurality of numerical values with said corrected value if the result of one or more calculations is less than one or more predetermined set points; wherein the one or more calculations includes at least one from the group consisting of an absolute value of a difference between said corrected value and a second of said plurality of numerical values, an absolute value of a percent difference between said corrected value and said second of said plurality of numerical values, an absolute value of the difference between said corrected value and an arithmetic mean at least said second and a third of said plurality of numerical values, and a standard deviation of said corrected value and at least said second and said third of said plurality of numerical values; wherein said repair algorithm is structured to replace said second of said plurality of numerical values with a repair value if said second of said plurality of numerical values differs significantly from said first of said plurality of numerical values; and wherein said first algorithm will generate an output signal so as to cause said fuel injector to introduce fuel to said engine at an appropriate flow rate for said engine speed and said engine load based on said corrected value or said second of said plurality of numerical values, and said target air-fuel ratio.