Fuel System Diagnostics via Vibration-Based Combustion Analysis
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Solution Overview
Problem
Existing techniques for internal combustion engines lack the ability to effectively determine and address factors causing changes in combustion characteristics beyond fuel quantity variations, such as faulty fuel injectors or fuel quality changes, which can impact closed-loop control and emissions.
Innovation Solution
A non-intrusive combustion sensor system utilizing an accelerometer to detect vibrational signals from in-cylinder pressure changes, coupled with a diagnostic logic tree and reconstruction algorithm, allows for real-time detection and mitigation of factors influencing combustion characteristics, including fuel injector issues and fuel quality variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct in-cylinder pressure measurement is used to obtain combustion information, then measurement precision is improved, but device complexity and cost increase due to required machining and sensor installation
Solution Approach 1:
The patent uses accelerometer sensors mounted on the engine block as an intermediary to indirectly measure combustion characteristics. Instead of placing sensors directly in the combustion chamber, the system measures vibrations transmitted through the engine block, which correlate with in-cylinder pressure changes. This intermediary approach maintains measurement precision while avoiding complex machining and sensor installation.
Solution Approach 2:
The patent replaces direct mechanical pressure measurement systems with vibrational sensing. By using accelerometers to detect mechanical vibrations caused by combustion events and transmitting these signals through the engine block, the system substitutes a simpler mechanical vibration measurement approach for complex direct pressure measurement, reducing device complexity while maintaining diagnostic capability.
2Reliability
If existing combustion sensor techniques are used, then in-cylinder pressure measurement is achieved, but the ability to detect fuel quality changes and injector faults is insufficient
Solution Approach 1:
The patent segments the combustion diagnostic process into multiple analysis components: heat release rate calculation, combustion phasing analysis, vibration signal processing, and pattern recognition. By dividing the diagnostic function into these segments, the system can independently analyze different aspects of combustion including fuel quality effects and injector performance, preventing information loss while maintaining reliability.
Solution Approach 2:
The patent monitors changes in combustion parameters such as heat release rate, combustion duration, and vibration characteristics to detect fuel quality variations and injector faults. By tracking parameter changes over time and comparing against reference values, the system gains the ability to detect fuel quality changes and injector status without losing critical diagnostic information, enhancing both reliability and information completeness.
3Device complexity
If non-intrusive accelerometer sensing is used, then device complexity is reduced, but measurement precision for combustion characteristics decreases
Solution Approach 1:
The patent performs preliminary calibration and establishes reference combustion patterns under known operating conditions before actual diagnostic operation. By pre-characterizing the relationship between combustion events and vibrational signals for different fuel qualities and injector states, the system compensates for the indirect measurement approach, maintaining measurement precision while benefiting from the simplicity of non-intrusive sensor installation.
Solution Approach 2:
The patent implements feedback mechanisms where measured vibration signals are continuously compared against expected combustion patterns, and corrections are applied to maintain measurement accuracy. The system uses feedback from multiple sensors and iterative signal processing to compensate for the indirect nature of accelerometer-based measurement, ensuring precision is maintained despite the simplified installation approach.
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 continuous engine operation with improved combustion control, reduced emissions, and accurate identification of hardware issues or fuel quality changes, allowing for timely corrections and maintaining optimal engine performance.
Implementation Method 1
A signal from the accelerometer sensor is received at the electronic controller. The signal is representative of in-cylinder pressure changes.
Data Source
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AI summary
A method and apparatus for in situ operating an internal combustion engine comprising determining at least one combustion characteristic for a combustion chamber of the internal combustion engine, comprising an actual heat release signal for the combustion chamber; and inputting the actual heat release signal into a diagnostic logic tree for diagnosing changes in combustion characteristics due to at least one of: a malfunctioning fuel injector, a start of combustion timing error; and a change in fuel quality; and performing a mitigation technique to compensate for the changes in combustion characteristics.