A survey of spark plug production testing tools and techniques

Despite 150 years' evolution, spark plug design and production testing methods have remained largely unchanged since their invention. Spark plug production is a complex process and there are many opportunities for faults to be manifested. During most of the history of spark plugs, an ingenious yet relatively simple "go/no go" batch test has been the test of choice, as it is rapid and well-proven for a variety of the most common faults. However, in recent years, some major disadvantages with this test have come to light. This paper describes the existing state of the art of spark plug testing tools and techniques, discovered during a comprehensive literature review. The predominant production spark plug testing system is evaluated, with a view to devising a more advanced method of spark plug testing. The work concludes that there is a need for a new production spark plug test, ideally offering: further increased reliability of fault detection, capacity for diagnosis of faults, high speed, and easier compliance with Health and Safety legislation.