Hydrogen Engine Pre-Ignition Detection Using Accumulated Vibration Signals
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Solution Overview
Problem
Determining pre-ignition in internal combustion engines using hydrogen fuel is challenging due to low vibrations generated, making it difficult to differentiate between normal and abnormal combustion using existing peak value detection methods.
Innovation Solution
An apparatus that calculates an accumulated value of the output from a vibration sensor over a prescribed period before ignition and compares it with a threshold set based on engine operating conditions to determine pre-ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If peak value detection method is used for pre-ignition determination, then the detection method is simple, but detection reliability deteriorates when vibrations are low (hydrogen fuel engines)
Solution Approach 1:
The patent transitions from one-dimensional peak value detection to two-dimensional analysis by accumulating vibration values over a specific time period (from 360° before ignition timing to 180° before ignition timing). This temporal dimension allows detection of low-amplitude pre-ignition vibrations that would be missed by peak value alone, thereby improving reliability without requiring additional sensors or complex hardware
Solution Approach 2:
The patent performs preliminary accumulation of vibration values during the compression stroke (360° to 180° before ignition timing) before the actual combustion occurs. This preliminary action captures the characteristic vibration pattern of pre-ignition events, enabling reliable detection even when the subsequent combustion vibrations are low, as is the case with hydrogen fuel
2Measurement precision
If accumulated value calculation is performed over extended period, then detection accuracy improves, but processing time increases
Solution Approach 1:
The patent segments the detection period into a specific range (360° to 180° before ignition timing) rather than accumulating over the entire engine cycle. This segmentation focuses computation on the critical period where pre-ignition vibrations occur, improving detection accuracy while minimizing processing time by excluding irrelevant periods
Data Source
AI summary
A pre-ignition determining apparatus for an internal combustion engine using hydrogen as fuel is configured to determine an occurrence of pre-ignition based on an output value of a vibration sensor provided in the internal combustion engine. The pre-ignition determining apparatus includes processing circuitry that is configured to execute an accumulation process of calculating an accumulated value of the output value within a prescribed period prior to an ignition timing of an air-fuel mixture, and a determination process of determining the occurrence of pre-ignition based on the accumulated value.