Accelerometer-Based Cylinder Pressure Peak Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for detecting misfires and partial combustion in internal combustion engines are inefficient, particularly due to difficulties in accurately measuring in-cylinder pressure, which is crucial for diagnosing combustion anomalies, and existing techniques are either expensive or require structural modifications and high-temperature sensors.
Innovation Solution
A method using an accelerometer mounted on the engine body to sense vibrations, with band-pass filtering and fuzzy logic to diagnose misfires and partial combustion by correlating acceleration signals with in-cylinder pressure peaks, allowing for non-intrusive and cost-effective detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct pressure measurement inside each cylinder is used, then measurement precision of combustion quality is improved, but device complexity and cost increase due to required high-temperature sensors and structural modifications
Solution Approach 1:
The patent uses accelerometer-based vibration sensing as an intermediary method to indirectly measure combustion quality without requiring direct pressure sensors inside the cylinder. The vibration signals from the engine block serve as a mediator that correlates with combustion events, allowing detection of misfires and partial burning through signal processing rather than direct pressure measurement
Solution Approach 2:
The patent replaces the mechanical/direct pressure measurement system with an accelerometer-based vibration sensing system. Instead of using pressure sensors that require structural modifications and high-temperature resistance, the system uses accelerometers mounted on the engine block to detect vibrations caused by combustion, substituting a simpler mechanical sensing approach
2Ease of operation
If crankshaft speed fluctuation method is used, then ease of operation is improved, but measurement precision of misfire detection deteriorates under certain conditions
Solution Approach 1:
The patent utilizes mechanical vibration sensing through accelerometers mounted on the engine block to detect combustion events. By analyzing vibration signals in specific frequency ranges and time windows corresponding to combustion cycles, the system can detect misfires and partial burning with higher precision than crankshaft speed methods, while maintaining ease of operation through non-intrusive sensor placement
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 provides a simple and effective means to detect pressure peaks and diagnose combustion anomalies, improving engine control and reducing emissions by correlating vibrational waveforms with internal pressure signals, enhancing detection accuracy and reducing hardware costs.
Implementation Method 1
at least an accelerometer installed on the engine body for sensing vibrations of the engine
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A simple and effective method and a related device for detecting a pressure peak value during a pressure cycle in a cylinder of an internal combustion engine is proposed. An accelerometer is installed on the engine body for sensing vibrations of the engine during its functioning and a band-pass replica of the output acceleration signal is compared with a threshold and an active logic flag is generated when the threshold is exceeded. The band-pass filtered replica of the acceleration signal is obtained by filtering out frequency components smaller than about 1 kHz and larger than about 2 kHz.