Spark Plug Defect Detection via Ignition Coil Current Rise Time
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Solution Overview
Problem
Spark plugs in spark-ignited internal combustion engines experience high wear and failure rates, leading to potential engine shutdowns and damage, which can negatively impact operation and productivity.
Innovation Solution
Determine the condition of a spark plug by analyzing the rise time of the primary current through the ignition coil's primary winding, comparing it to a reference time, and using this to predict the spark plug's remaining service life and detect defects, allowing for controlled engine shutdowns before failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spark plugs are used in internal combustion engines, then ignition function is achieved, but wear and failure rates increase leading to emergency stops
Solution Approach 1:
The system performs preliminary detection of spark plug defects by monitoring ignition delay times before complete failure occurs. The control unit continuously measures the time interval between current supply start and maximum current reach, comparing it against reference values to identify degradation trends early, allowing scheduled maintenance before emergency stops are necessary
Solution Approach 2:
The system implements feedback monitoring by continuously measuring ignition delay times and comparing them against reference values stored in memory. When the measured delay exceeds the reference by a threshold amount, the control unit generates a defect indication signal, creating a closed-loop monitoring system that provides real-time feedback on spark plug condition
2Reliability
If emergency stop is initiated due to spark plug failure, then engine damage is prevented, but operation and productivity are negatively affected
Solution Approach 1:
The system performs preliminary detection of spark plug defects by monitoring ignition delay times before complete failure occurs. By identifying degradation trends early through continuous measurement and comparison against reference values, the system enables planned maintenance scheduling during non-critical periods, preventing unexpected emergency stops and associated downtime
Solution Approach 2:
The system prepares for potential spark plug failure by continuously monitoring ignition delay and maintaining defect detection capability ready. The control unit is pre-configured with reference values and threshold criteria, so when degradation is detected, the system can immediately indicate a defect condition and schedule maintenance before actual failure occurs, cushioning against the impact of unplanned downtime
3Measurement precision
If continuous monitoring of spark plug condition is implemented, then defect detection is improved, but device complexity increases
Solution Approach 1:
The system uses the existing primary current measurement infrastructure to detect spark plug defects without requiring separate dedicated sensors. The control unit leverages current measurements already being taken for ignition control purposes, analyzing the timing characteristics of the primary current waveform to infer spark plug condition, thereby achieving defect detection using existing system resources
Solution Approach 2:
The control unit performs multiple functions: it controls ignition timing, monitors primary current for defect detection, stores reference values, and generates defect indications all within a single integrated unit. This multi-functionality eliminates the need for separate dedicated monitoring hardware, reducing overall system complexity while maintaining precise defect detection capability
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
Enables the detection of spark plug defects, preventing emergency stops and allowing continued operation for several days or weeks, thereby increasing engine reliability and productivity by scheduling timely replacements.
Implementation Method 1
a current is selectively supplied to the primary winding to induce a magnetic field in the secondary winding. This results in an increase in the voltage across the spark plug, and eventually the spark plug is discharged
Data Source
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AI summary
In a method for determining a defect in a spark plug (12) associated with a cylinder (26) of a spark-ignited internal combustion engine (10), an ignition delay from starting a supply of current to a primary winding (16) of an ignition coil (14) associated with the spark plug (12) to reaching a maximum value of the supplied current is determined. When the ignition delay is above a threshold defined in advance for the spark plug (12), it is determined that the spark plug (12) is defective or approaches the end of its service life and should be replaced. A corresponding indication is output to an operator of the internal combustion engine (10) to allow for scheduling a downtime of the engine for exchanging the spark plug (12).