Ion Current Timing Comparison for Abnormal Combustion Detection
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Solution Overview
Problem
Conventional internal-combustion-engine combustion state detecting apparatuses face challenges in accurately detecting abnormal combustion due to the peak position of cylinder inner pressure occurring immediately before or after ignition, making it difficult to distinguish the ion current peak timing from the cylinder inner pressure peak timing, leading to inefficient engine performance and durability issues.
Innovation Solution
An internal-combustion-engine combustion state detecting apparatus that generates multiple ignition signals during a single compression or power stroke, utilizing an ion detection device to detect electric quantities, an ending timing detection device to set a comparison timing advanced relative to normal ignition, and a combustion diagnosis device to diagnose abnormal combustion based on the comparison, while masking noise and preventing erroneous diagnoses through leakage and foreign material detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If ion current detection is used to detect peak cylinder pressure position, then the detection capability is improved, but the detection accuracy deteriorates because the peak position occurs during spark discharge when no ion current can be detected
Solution Approach 1:
The patent introduces a comparison timing as an intermediary reference point. Instead of directly detecting the peak position during the problematic spark discharge period, the system establishes a comparison timing advanced by a predetermined crank angle from the normal ion current peak timing. This intermediary reference enables indirect detection and resolution of the peak position without being affected by the spark discharge interference.
Solution Approach 2:
The patent applies preliminary action by setting the comparison timing in advance, advanced by a predetermined crank angle from the expected peak position. This allows the system to prepare the reference timing before the actual combustion event occurs, enabling accurate comparison and detection even when the peak occurs during the spark discharge period when direct ion current detection fails.
2Device complexity
If ion current peak timing is used to represent flame angle, then the measurement is simplified, but the accuracy deteriorates because it cannot be distinguished from cylinder inner pressure peak timing
Solution Approach 1:
The comparison timing serves as an intermediary that bridges the gap between ion current peak timing and cylinder pressure peak timing. By establishing this reference timing advanced by a predetermined crank angle, the system can indirectly determine the actual peak position and distinguish between different combustion states without directly measuring both parameters simultaneously, thus maintaining simplicity while improving accuracy.
3Adaptability or versatility
If multiple ignition signals are generated during a single stroke, then the combustion control flexibility is improved, but the detection complexity increases due to multiple ion current signals
Solution Approach 1:
The patent extracts and focuses on the first ion current signal among multiple ignition signals. By selecting and processing only the first signal's peak timing for comparison with the predetermined comparison timing, the system simplifies the detection process despite generating multiple ignition signals. This extraction approach maintains combustion control flexibility while avoiding the complexity of processing all multiple signals.
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
Accurately detects abnormal combustion, enhancing engine efficiency, reducing fuel depletion, and contributing to environmental conservation by preventing engine damage and improving durability.
Implementation Method 1
an ion detection device that is provided in the ignition device and detects an electric quantity based on an ion that occurs in the combustion chamber due to combustion of the fuel-air mixture
Implementation Method 2
an ignition device that generates a plurality of ignition signals during a single compression stroke or power stroke of an internal combustion engine so as to ignite and burn an inflammable fuel-air mixture
Data Source
AI summary
There is provided a combustion state detecting apparatus capable of detecting combustion-state abnormality in an internal combustion engine. A comparison timing is set to be advanced in terms of the rotation angle of the crankshaft of an internal combustion engine with respect to the ending timing of an electric quantity based on an ion that occurs when ignition is performed normally through a predetermined ignition signal among the plurality of ignition signals; in the case where, as a result of the comparison between the detected ending timing of an electric quantity based on an ion and the comparison timing, the ending timing is advanced in terms of the rotation angle of the crankshaft with respect to the comparison timing, it is determined that the combustion based on ignition through the predetermined ignition signal is abnormal.