High-Frequency Emission Plug With Isolated Outer Conductor
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Solution Overview
Problem
Conventional high frequency emission plugs risk causing high frequency noise due to electric current flowing through the casing, which can lead to unwanted electromagnetic interference when attached to internal combustion engines.
Innovation Solution
The plug design features a cylindrical casing with a non-contacting outer conductor and an embedded plate-like conductor, preventing electrical conduction to the casing and enhancing electromagnetic wave emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the casing is used as an outer conductor of a transmission line, then the device structure is simplified, but high frequency noise is emitted from the emission antenna due to electric current flowing through the casing
Solution Approach 1:
The transmission line is segmented into an inner conductor and an outer conductor, where the outer conductor is a separate component from the casing. This segmentation allows the outer conductor to be electrically isolated from the casing, preventing electric current from flowing through the casing to the emission antenna, thus eliminating high frequency noise while maintaining the transmission line structure
Solution Approach 2:
An insulator is introduced as an intermediary material between the outer conductor and the casing. This insulator prevents electrical conduction between the outer conductor and the casing, blocking the path of electric current that would otherwise flow through the casing to the emission antenna and generate high frequency noise
2Object-generated harmful factors
If the outer conductor is in non-contact with the casing, then high frequency noise is suppressed, but the transmission line structure becomes more complex
Solution Approach 1:
The insulator serves multiple functions: it provides electrical insulation between the outer conductor and the casing to prevent high frequency noise, and simultaneously provides mechanical support and positioning for the outer conductor within the casing. This multi-functionality reduces the need for additional components, thereby limiting the increase in device 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 design effectively suppresses high frequency noise emissions by isolating the outer conductor from the casing, ensuring that electric currents do not induce noise in the emission antenna, even when attached to a target object like a cylinder head.
Implementation Method 1
a transmission line for transmitting an electromagnetic wave; an emission antenna for emitting the electromagnetic wave supplied via the transmission line
Implementation Method 2
the outer conductor is disposed in the casing in a manner to be held in non-contact with the casing
Data Source
AI summary
An aim of the present invention is, in a plug for high frequency emission disposed at an end of a casing having an emission antenna, to suppress a high frequency noise emitted from the emission antenna. The present invention is directed to a plug for high frequency emission including a transmission line for transmitting an electromagnetic wave, an emission antenna for emitting the electromagnetic wave supplied via the transmission line, and a casing constituted by a cylindrical shaped conductor, provided with the emission antenna at one end of the casing, and accommodating therein the transmission line extending from the emission antenna toward the other end of the casing. Inside of the casing, a central conductor electrically connected to the emission antenna and an outer conductor spaced apart from and surrounding the central conductor are embedded in an insulator so as to collectively constitute the transmission line, and the outer conductor is disposed in and held in non-contact with the casing.