Internal Combustion Engine Ion Current Detection Smolder Preignition
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Solution Overview
Problem
Conventional internal-combustion-engine combustion condition detection methods struggle to accurately distinguish between smoldering and preignition due to overlapping leakage and ion current durations, leading to inaccurate detection and potential engine damage.
Innovation Solution
The detection ranges for leakage and ion currents are set during different engine strokes, allowing for separate and secure detection of smoldering and preignition, with the leakage current detection range set within the non-combustion stroke and ion current detection range set during the combustion stroke, enabling wider detection ranges and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detection ranges for leakage current and ion current are set during the same engine stroke, then the detection system can operate continuously, but the detection accuracy decreases due to overlapping current signals making it difficult to distinguish between smoldering and preignition
Solution Approach 1:
The patent divides the detection process into two separate time segments: leakage current detection is performed during the non-combustion stroke, while ion current detection is performed during the combustion stroke. This temporal segmentation eliminates signal overlap and allows accurate distinction between smoldering (detected via leakage current) and preignition (detected via ion current) without requiring complex signal processing to separate overlapping currents.
2Measurement precision
If the leakage current detection range is set during the combustion stroke, then the detection can be performed during normal operation, but the detection accuracy decreases because combustion ion currents interfere with leakage current measurements
Solution Approach 1:
The patent performs leakage current detection during the non-combustion stroke, which occurs before the combustion stroke. This preliminary detection allows the system to identify smoldering conditions before they potentially lead to preignition, maintaining high detection accuracy without losing critical detection time, as the non-combustion stroke is part of the normal engine cycle.
3Adaptability or versatility
If wider detection ranges are used for both leakage and ion currents, then the detection coverage is improved, but the ability to distinguish between different fault conditions decreases due to signal overlap
Solution Approach 1:
The patent introduces a temporal dimension to the detection process by assigning different time windows for detecting different fault conditions. Leakage current detection is confined to the non-combustion stroke while ion current detection is confined to the combustion stroke. This temporal dimension allows the system to use wider detection ranges within each time window without causing signal overlap, thereby maintaining both wide coverage and precise fault differentiation.
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 enables secure detection of both smoldering and preignition, enhancing determination accuracy and preventing engine damage by clearly differentiating between the two conditions.
Implementation Method 1
due to combustion in a combustion chamber, the molecules of a mixture gas in the combustion chamber ionize, and when a voltage is applied to the ionized combustion chamber through the ignition plug, a minute current flows. The minute current is referred to as an ion current.
Implementation Method 2
the value of the insulation resistance across the electrodes of the ignition plug decreases, whereby a spark becomes unlikely to occur. This phenomenon is commonly known as 'soiling of an ignition plug due to smoldering'. In addition, the phenomenon is referred to as 'smoldering' in which the value of the insulation resistance across the electrodes of an ignition plug decreases and thereby a leakage current occurs across the electrodes of the ignition plug.
Data Source
AI summary
An internal-combustion-engine combustion condition detection apparatus is provided with an ignition means that makes an ignition plug ignite a fuel; an ignition control means that controls the operation of the ignition means; an ion-current detection means that detects an ion current generated; an ion current detection range setting means that sets an ion-current detection range; a preignition detection means that detects preignition within a detection range to be set; a leakage current detection range setting means that sets a leakage-current detection range; and a leakage current determination means that determines whether or not a smolder exists, based on a current detected, within a detection range to be set, by the ion-current detection means. The ignition control means includes a non-combustion-stroke ignition control means; the leakage-current detection range set by the leakage current detection range setting means is set within the non-combustion stroke.Accordingly, both a smolder detection and a preignition detection can securely be performed.