Fuel Injector Map Indexing via Pressure Transformation
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Solution Overview
Problem
The existing common rail fuel system's injector map interpolation method results in inaccuracies due to non-linear relationships between fuel injector activation data, leading to decreased fuel consumption efficiency and increased emissions variation.
Innovation Solution
Indexing the injector map using a modified pressure function, such as the square root of the fuel rail pressure, transforms the data to be more linear, reducing interpolation errors and improving the accuracy of fuel injector activation times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If linear interpolation is used between fuel rail pressure values in the injector map, then the controller can determine injector activation time from finite data points, but interpolation error increases due to non-linear relationship between pressure and fuel injector activation data
Solution Approach 1:
The patent transforms the independent variable from fuel rail pressure to a function of fuel rail pressure (e.g., square root of pressure, logarithm of pressure). This parameter transformation changes the non-linear relationship between pressure and injector activation time into a more linear relationship, thereby reducing interpolation error while maintaining the finite data point structure of the injector map.
2Quantity of substance
If the injector map includes a finite number of data points, then the memory requirements are reduced, but exact measured fuel rail pressure and desired fuel value may not be included requiring interpolation
Solution Approach 1:
By changing the parameter used to index the injector map from direct pressure values to transformed pressure values (such as square root of pressure or logarithmic transformation), the patent achieves a more linear data distribution. This allows for more accurate interpolation between finite data points, reducing precision loss while maintaining compact memory storage.
3Productivity
If linear interpolation is performed on non-linear data, then the calculation is simple and fast, but interpolation inaccuracies increase leading to decreased fuel consumption efficiency and increased emissions variation
Solution Approach 1:
The patent applies a mathematical transformation to the pressure parameter (independent variable) in the injector map. This transformation converts the non-linear relationship into a more linear one, allowing simple linear interpolation to achieve higher accuracy. The transformed parameter maintains computational simplicity while significantly improving the reliability of fuel injection control, thereby improving fuel efficiency and reducing emissions variation.
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 non-transitory computer readable storage medium with memory comprises fuel injector activation data indexed in the memory according to an input parameter, instructions for determining a modified pressure value based on a determined pressure and a modified pressure function, and instructions for generating a fuel injector activation output by interpolating among the indexed fuel injector activation data with the modified pressure value as the input parameter.