Engine Knock Detection via Dynamic Background Noise Learning
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Solution Overview
Problem
Existing methods for detecting engine knock via vibration sensors are unreliable due to changes in engine operating conditions, leading to false indications or missed detections of engine knock, as they fail to accurately account for varying engine background noise levels.
Innovation Solution
The method involves retarding spark timing and adjusting fuel injector operations to learn and establish a base engine knock background noise level, which is then used to determine knock intensity levels, thereby compensating for changes in engine conditions and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If engine background noise level is used as a fixed threshold for knock detection, then the detection method is simple, but detection reliability deteriorates due to changes in engine operating conditions
Solution Approach 1:
The patent implements dynamic adaptation of the knock detection system by continuously learning and updating the background noise level based on current engine operating conditions. The system transitions from a static threshold to a dynamic one that automatically adjusts to changing conditions such as engine age, temperature, and load, thereby maintaining high detection reliability without requiring complex manual calibration.
Solution Approach 2:
The system performs self-learning of the background noise level by automatically adapting to changes in engine conditions over time. Through continuous monitoring and learning operations, the system updates its own reference values without external intervention, enabling it to compensate for aging effects and operating condition variations autonomously.
2Productivity
If spark timing is advanced to maximize power output, then engine productivity is improved, but knock occurrence increases leading to degraded detection accuracy
Solution Approach 1:
The system performs preliminary learning operations to establish the background noise level under various operating conditions before actual knock detection begins. By pre-characterizing the engine's noise profile during normal operation, the system prepares accurate reference values that enable reliable knock detection even when the engine operates at maximum power output with advanced spark timing.
3Use of energy by moving object
If direct fuel injection is used to improve fuel efficiency, then energy consumption is reduced, but noise from injector operation interferes with knock detection
Solution Approach 1:
The patent extracts and isolates the injector noise component from the overall engine noise signal by performing separate learning operations. The system specifically learns the noise characteristics generated by direct fuel injector operation and separates this from the true knock signal, enabling accurate knock detection despite the presence of injector-induced noise.
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 enhances the reliability of engine knock detection by accurately accounting for changing noise levels, reducing false indications and improving confidence in knock intensity values, thus enabling effective mitigation strategies.
Implementation Method 1
High frequency pressure oscillations within the cylinder may generate an engine knocking sound that may be captured by the vibration sensor
Data Source
AI summary
Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual noise sources to an engine background noise level. The contributions of the individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders.