Fuel Injection Quantity Correction via Pressure Gradient Spectrum
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Solution Overview
Problem
Existing methods for controlling fuel injection in internal combustion engines face challenges in precision and accuracy due to dynamic pressure changes in the high-pressure accumulator, leading to inconsistent fuel injection quantities across cylinders.
Innovation Solution
A method that detects pressure gradients during angular synchronism, transforms the pressure and gradient spectra into frequency space, and corrects the pressure spectrum to determine cylinder-specific fuel injection quantities, using a model that accounts for fluid temperature and amplitude/phase characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure detection is performed during multiple consecutive injections to determine injection quantity, then measurement precision is improved, but the pressure gradient causes injection quantity falsification
Solution Approach 1:
The patent converts the harmful pressure gradient effect into a beneficial correction factor. By detecting the pressure gradient during multiple injections and using it to correct the pressure values, the system transforms the source of measurement error into a tool for improving measurement accuracy. The pressure gradient, which initially causes falsification, is now used to compensate for other measurement errors in the system.
Solution Approach 2:
The patent implements a feedback mechanism where pressure values detected during consecutive injections are used to calculate a correction factor, which is then applied to subsequent pressure measurements. The system continuously monitors the pressure gradient and adjusts the correction values accordingly, creating a closed-loop feedback system that improves measurement precision while compensating for the pressure gradient effect.
2Measurement precision
If frequency transformation is applied to pressure data for injection quantity determination, then measurement precision is improved, but computational complexity increases
Solution Approach 1:
The patent applies preliminary correction to the pressure data before performing frequency transformation. By pre-correcting the pressure values using the pressure gradient compensation method, the system reduces the complexity of the subsequent frequency transformation step. This preliminary action ensures that the frequency transformation operates on already-corrected data, reducing computational burden while maintaining precision.
Solution Approach 2:
The patent replaces direct time-domain analysis with frequency-domain analysis through Fourier transformation. This substitution allows for more precise injection quantity determination by analyzing the frequency components of the pressure signal, which reveals information about the injection events that is not apparent in the time domain. The computational complexity is managed by performing the transformation on corrected data and focusing analysis on specific frequency bands.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for precise and efficient fuel injection, even under non-steady state conditions, by reducing computational steps and preventing injection quantity falsification, thereby improving the accuracy and ease of implementation in engine controllers.
Implementation Method 1
a pressure sensor arranged to detect, under conditions of angular synchronism, a pressure of the fuel in the high-pressure accumulator
Implementation Method 2
The detected pressure and/or the ascertained gradient may be transferred to a frequency space, for example with the aid of a discrete Fourier transformation
Data Source
AI summary
A method for operating an internal combustion engine is provided in which fuel is withdrawn from a high-pressure accumulator and injected into a combustion chamber of at least one cylinder of the internal combustion engine, the method including the steps of detecting under conditions of angular synchronism a pressure of the fuel in the high-pressure accumulator during a first injection into the at least one cylinder and during a later, second injection into the at least one cylinder; ascertaining a gradient of the detected pressure; ascertaining a frequency-transformed spectrum of the detected pressure and a frequency-transformed spectrum of the ascertained gradient; correcting the frequency-transformed spectrum of the detected pressure by the frequency-transformed spectrum of the ascertained gradient; and ascertaining a cylinder-individual injection quantity of fuel, which was injected into the at least one cylinder, from the corrected frequency-transformed spectrum of the detected pressure.