Fuel Injector Map Indexing via Modified Pressure Difference
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Solution Overview
Problem
The existing common rail fuel system's injector maps lead to linear interpolation inaccuracies due to non-linear relationships between injector activation data, resulting in increased fuel injector activation time errors, decreased fuel consumption efficiency, and increased emissions variation.
Innovation Solution
Indexing the injector map by a modified pressure difference value, which is based on the pressure difference across the nozzle orifice, engine speed, injection timing, and a modified pressure difference function, transforms the data to be more linear, reducing interpolation errors and improving fuel injection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the injector map is indexed by fuel rail pressure only, then the system is simple to implement, but linear interpolation inaccuracies occur due to non-linear relationships between injector activation data
Solution Approach 1:
The patent transforms the indexing parameter from simple fuel rail pressure to a modified pressure difference value that accounts for the non-linear relationship between pressure and injector activation. This parameter transformation enables more accurate linear interpolation while maintaining system simplicity.
Solution Approach 2:
The patent introduces a modified pressure difference function as an intermediary that bridges the gap between simple pressure indexing and accurate injector activation timing. This intermediary transformation allows the system to achieve high precision without complex multi-dimensional indexing.
2Productivity
If traditional injector maps are used with linear interpolation, then the system is computationally efficient, but fuel consumption efficiency decreases due to activation time errors
Solution Approach 1:
By changing the indexing parameter to modified pressure difference, the system maintains computational efficiency through linear interpolation while significantly reducing activation time errors that lead to fuel waste.
Solution Approach 2:
The patent replaces the traditional mechanical approach of using complex multi-dimensional maps with a mathematical transformation approach, achieving both computational efficiency and fuel efficiency through the modified pressure difference function.
3Device complexity
If traditional injector maps are used, then the system is simple to implement, but emissions variation increases due to inaccurate fuel injection control
Solution Approach 1:
The modified pressure difference indexing transforms the relationship between pressure and injector activation to be more linear, reducing interpolation errors that cause emissions variation while keeping the implementation simple.
Data Source
AI summary
Various methods and systems are provided for indexing an injector map and subsequently controlling fuel injection to an engine. In one embodiment, a method for the engine includes injecting fuel via activating an injector for a determined activation time, the activation time determined based on a commanded fuel value and a function of a modified pressure difference across an orifice of a nozzle of the injector, where the modified pressure difference is based on a difference between a rail pressure and peak cylinder pressure, the peak cylinder pressure scaled by a function of engine speed and injection timing and the pressure difference offset by a correction factor.