Hydraulic Start-of-Injection Detection Using In-Cylinder Pressure Sensors
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Solution Overview
Problem
Current engine systems lack accurate detection of hydraulic start-of-injection (SOI) timing, which is crucial for controlling emissions and fuel economy, as they rely on electronic control and do not account for hydraulic delays, leading to potential inefficiencies and increased emissions.
Innovation Solution
A system and method utilizing in-cylinder pressure sensors and wavelet transforms to determine hydraulic SOI timing by analyzing pressure signals, allowing for diagnostic and control opportunities in high-pressure fuel rail engine systems without the need for specialized injectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electronic control is used to control SOI timing, then control precision is improved, but hydraulic delay detection capability deteriorates
Solution Approach 1:
The patent introduces an in-cylinder pressure sensor as an intermediary device to detect pressure pulsations caused by fuel injection. This mediator captures hydraulic delay information that would otherwise be lost in electronically controlled systems, enabling indirect measurement of actual hydraulic SOI timing through pressure signal analysis.
Solution Approach 2:
The patent replaces direct mechanical measurement methods with electronic pressure sensing and signal processing. Instead of using mechanical indicators to detect SOI timing, the system uses electronic pressure sensors combined with wavelet transform algorithms to extract hydraulic delay information from pressure pulsations, achieving both precision and information retention.
2Measurement precision
If in-cylinder pressure sensors and wavelet transforms are used to detect hydraulic SOI timing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential frequency band containing hydraulic SOI information from the complex pressure signal using wavelet transform. By isolating and analyzing only the relevant frequency components rather than processing the entire signal spectrum, the system achieves precise hydraulic SOI detection while reducing computational complexity.
Solution Approach 2:
The patent transforms the pressure signal from the time domain to the frequency domain through wavelet transform, changing the parameter representation to make hydraulic delay information more accessible. This parameter transformation enables precise measurement of SOI timing by analyzing frequency characteristics rather than raw pressure values.
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
Enables accurate detection of hydraulic SOI timing, improving fuel injector operation, reducing emissions, and enhancing fuel economy by providing precise timing adjustments and diagnostic feedback.
Implementation Method 1
a wavelet transform of the sampled signal is calculated to determine a frequency band of pressure pulsations excited from a fuel jet injected into the cylinder
Data Source
AI summary
This disclosure provides system and method that can determine hydraulic start of injection (SOI) in engines using an in-cylinder pressure sensor. The system and method iteratively perform a wavelet transform on a signal based on the pressure information provided by the in-cylinder pressure sensors to determine a detail coefficient corresponding to a frequency band containing frequencies of pressure pulsations excited from a fuel jet injected into the cylinder. Hydraulic SOI is determined at the timing when the amplitude of the determined detail coefficient satisfies a predetermined threshold. The system and method provide diagnostic, control, and/or compensation opportunities for fuel injector operation in high pressure fuel rail engine systems without use of expensive or complex fuel injector components.