Spark Plug Ground Electrode Deviation Measurement
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Solution Overview
Problem
Subjective visual inspections of spark plug ground electrode deviations from the optimal igniting position lead to variations in quality judgments, as the accuracy of deviation measurement is inspector-dependent.
Innovation Solution
A method using a female thread jig to measure the deviation of the ground electrode from the joint target position by calculating the shortest distance between the electrode axis and a reference straight line, employing non-contact or contact-type displacement sensors for accurate and precise measurement, thereby reducing subjective errors and ensuring consistent quality evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If visual inspection is used to check ground electrode deviation, then the inspection process is simple and fast, but measurement accuracy deteriorates due to subjective judgment variations
Solution Approach 1:
The patent replaces the manual visual inspection method with an automated optical measurement system. A camera captures images of the ground electrode position, and image processing algorithms automatically calculate the deviation from the optimal igniting position, eliminating subjective human judgment while maintaining fast inspection speed
Solution Approach 2:
The patent introduces a female thread jig as an intermediary reference tool. This jig provides a standardized reference position that represents the optimal igniting position, allowing the measurement system to objectively compare the actual ground electrode position against this reference without relying on inspector subjectivity
2Measurement precision
If automated image processing is used to determine ground electrode position, then measurement objectivity improves, but device complexity increases
Solution Approach 1:
The patent uses a camera to create an optical copy (image) of the ground electrode position. This optical copy is then processed through image processing algorithms to extract position information, replacing complex mechanical measurement devices with simpler optical and computational components
Solution Approach 2:
The female thread jig serves multiple functions: it provides a reference position for measurement, simulates the actual engine cylinder head thread, and enables standardized torque application. This multi-functionality reduces the need for separate reference tools and measurement fixtures
Data Source
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AI summary
An object of the present invention is to improve a measurement accuracy of a deviation from a joint target position of a member to which a measuring object is joined, and to improve a measurement speed. The deviation of a ground electrode 30 from an optimal igniting position O1 is measured while a metallic shell 50 is engaged with a female thread jig 300. A distance "ε" between an axis A of the ground electrode 30 and a reference straight line LS is calculated. The distance "ε" is a vertical length from the axis A to the reference straight line LS. An angle "α" between a first straight line L1 and the reference straight line LS is calculated using the distance "ε" and a predetermined distance "β" between the axis A of the ground electrode 30 and an axis O of the metallic shell 50.