Screening- and spring-interface between spark plug and helical coil in motor vehicle ignition system, uses C-shaped spring with radially inward protuberances for mechanically and electrically contacting the spark plug earth

摘要

High frequency (HF) interference from a helical coil, which includes a protective screen for reducing RFI is problematic as a significant source of HF interference is the electrical path running from the secondary winding and the secondary current runs through the components which are arranged outside the screen. To form an interface between the helical coil and a spark-plug requires a mainly C-shaped spring which is designed such that it is mechanically and electrically in engagement with the helical spring screen and is designed so an electrical contact is made with a spark plug earth, while the spring is mechanically and electrically in contact with the helical spring screen.