Engine Imbalance Detection via Generator Frequency Analysis
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Solution Overview
Problem
Multi-cylinder engines face issues with uneven fueling and cylinder degradation, leading to engine misfire and efficiency decreases, which can cause stress on components and increase costs due to the use of additional sensors for balancing.
Innovation Solution
A system that uses a generator and sensors to measure parameters like DC link voltage, engine speed, and shaft torque to detect engine imbalance based on frequency content, without additional sensors, accounting for contributions from other system components to reduce false positives and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual cylinder pressure sensors are used for measuring in-cylinder pressure, then measurement precision of cylinder pressure is improved, but device complexity and cost increase
Solution Approach 1:
The existing generator is made to serve a dual function: electricity generation and engine imbalance detection. By analyzing the frequency content of the generator output signal, the system detects engine imbalance without requiring dedicated sensors, thus reducing device complexity while maintaining diagnostic capability
Solution Approach 2:
The generator's own output signal is utilized for self-diagnosis of engine imbalance. The system monitors the generator's electrical output and extracts imbalance information from its frequency content, allowing the system to self-monitor without external sensing equipment
2Measurement precision
If individual cylinder pressure sensors are used for measuring in-cylinder pressure, then measurement precision is improved, but reliability decreases due to exposure to high combustion gas pressures and temperatures
Solution Approach 1:
The generator output signal serves as an intermediary that indirectly reflects engine cylinder performance. Instead of placing sensors directly in the harsh combustion environment, the system uses the generator's electrical output as a mediator to detect imbalance caused by cylinder degradation or fueling errors, thereby avoiding exposure to high temperatures and pressures
3Device complexity
If DC link voltage is used to detect engine imbalance, then device complexity is reduced, but false positive indications increase due to contributions from downstream loads
Solution Approach 1:
The system performs preliminary analysis of the frequency content of the DC link voltage signal to identify and filter out contributions from downstream loads before making imbalance determination. By pre-identifying load-related frequency components, the system can distinguish them from genuine imbalance signals, reducing false positives while maintaining simple device architecture
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 accurate detection of engine imbalance due to cylinder degradation or fueling errors, reducing costs and complexity while improving detection fidelity by identifying and adjusting for contributions from other sources.
Implementation Method 1
a generator coupled to an engine and configured to generate electricity from rotational movement of a shaft of the engine
Data Source
AI summary
A system includes a generator coupled to an engine and configured to generate electricity from rotational movement of a shaft of the engine, a sensor configured to measure one or more of a parameter of generator output, engine speed, or engine shaft torque, and a controller configured to detect engine imbalance based on a frequency content of a signal output from the sensor in response to a contribution to the frequency content from another component of the system being less than a threshold value.