Optical Spark Detection for Combustion Fault Diagnosis
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Solution Overview
Problem
Current methods for detecting faulty spark formation in spark-ignited internal combustion engines, particularly glow ignitions, are not sufficiently reliable, especially in powerful engines, as they often occur outside the expected time window and can be masked by regular combustion noise, leading to incomplete detection.
Innovation Solution
The method involves recording and evaluating the spark duration for each spark-ignition event in a cylinder, with faulty sparking detected when the spark duration exceeds a reference value, and using this data to identify irregularities in the combustion chamber, ignition coils, or spark plugs, including glow ignitions, by comparing individual spark durations to a mean value and considering load states and thermal loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional glow ignition detection methods are used (rotational speed measurement, knock signal evaluation, ion current detection), then detection capability is provided, but reliability is insufficient especially in powerful engines where glow ignitions occur outside expected time windows and are masked by regular combustion noise
Solution Approach 1:
The patent replaces mechanical vibration-based detection (knock sensors) and electrical field-based detection (ion current measurement) with optical detection using a light barrier across the spark plug gap. This optical method directly measures spark formation characteristics without being influenced by mechanical combustion noise or requiring complex signal processing, thereby improving reliability while maintaining simple device structure.
Solution Approach 2:
The patent introduces an optical intermediary (light barrier) between the spark plug electrodes to detect spark formation. This intermediary allows non-intrusive measurement of the spark gap conditions and spark duration, providing reliable detection of glow ignitions and faulty spark formation without interfering with the combustion process or requiring complex sensor systems.
2Measurement precision
If spark duration is recorded and evaluated for each spark-ignition event, then detection accuracy is improved, but measurement precision requirements increase
Solution Approach 1:
The patent uses optical detection with a light barrier to measure spark duration, replacing complex electrical field measurement systems. The optical method provides precise measurement of spark duration and characteristics without being affected by electrical noise or interference, thereby achieving both high measurement precision and high detection reliability simultaneously.
Solution Approach 2:
The light barrier system automatically detects and measures spark formation characteristics without requiring external calibration or complex signal processing. The system uses the spark itself as the measurement signal, with the light barrier simply detecting the presence and duration of the spark, thereby achieving precise measurement with minimal complexity.
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 provides a more reliable detection of faulty spark formation, enabling timely intervention to prevent engine damage by accurately distinguishing glow ignitions from regular combustion, even in complex engine conditions.
Implementation Method 1
a light barrier is provided across the spark plug gap for detecting light from a spark between the spark plug electrodes
Data Source
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AI summary
The method involves detecting spark combustion duration for a spark-ignition event of a cylinder of a spark-ignition internal combustion engine in a combustion cycle. Faulty spark formation in the cylinder is detected when the combustion duration or a variable derived from the combustion duration is equal to or greater than a reference value, where the reference value is dependent on load conditions of the internal combustion engine and/or the cylinder. An injector is disconnected after detection of a defective coil of a spark plug and/or a ceramic damage. An independent claim is also included for a device for detecting faulty spark formation of a spark-ignition internal combustion engine with cylinders, comprising a detecting unit.