Spark Plug Electrode Cooling via Internal Fuel Flow
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Solution Overview
Problem
In lean-operated gaseous fuel internal combustion engines with electric ignition, the ignition electrodes of spark plugs face high thermal stress, leading to damage and reduced service life.
Innovation Solution
A spark plug design with a fuel inlet on its surface supplies gaseous fuel to a recess adjacent to the electrodes, where it is discharged to cool them, using an annular groove and tangentially arranged flow channels to generate swirl and distribute fuel uniformly, thereby reducing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spark plug is used in a lean-operated gaseous fuel internal combustion engine, then efficient combustion is achieved, but the ignition electrodes face high thermal stress leading to damage and reduced service life
Solution Approach 1:
The patent introduces gaseous fuel as an intermediary cooling medium that flows through the spark plug body and directly contacts the ignition electrodes. This mediator absorbs excess heat from the electrodes without interfering with the combustion function, thereby resolving the contradiction between maintaining combustion efficiency and extending electrode service life under thermal stress
Solution Approach 2:
The patent utilizes pneumatic flow of gaseous fuel through internally configured passages within the spark plug body. The fuel is supplied under pressure through a fuel supply passage and distributed through flow channels to cooling surfaces, employing pneumatic principles to achieve effective cooling of the electrodes while maintaining the combustion function
2Reliability
If gaseous fuel is supplied to cool the electrodes, then thermal stress is reduced, but the spark plug structure becomes more complex with additional fuel inlet and flow channels
Solution Approach 1:
The patent merges the cooling function with the existing fuel supply system by integrating fuel supply passages and cooling flow channels into the spark plug body structure. The fuel supply passage and internal flow channels are combined with the electrode assembly housing, creating a multi-functional component that performs both ignition and cooling functions without requiring separate cooling systems
Solution Approach 2:
The spark plug body is designed as a multi-functional component that simultaneously performs electrical insulation, structural support, and thermal cooling functions. The fuel supply passage and flow channels are integrated into the insulator body, allowing the same structure to serve multiple purposes: maintaining electrical isolation while providing coolant flow paths for electrode cooling
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
The solution effectively cools the electrodes, enhancing their service life and maintaining efficient combustion in gaseous fuel internal combustion engines.
Implementation Method 1
A fuel inlet is formed in a surface of the spark plug body and is configured to receive a supply of gaseous fuel, and a fuel outlet is formed in the end of the spark plug body. The fuel outlet is fluidly communicated with the fuel inlet and is configured to discharge the gaseous fuel received at the fuel inlet from the spark plug.
Implementation Method 2
using an annular groove and tangentially arranged flow channels to generate swirl and distribute fuel uniformly
Data Source
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AI summary
The present disclosure relates to a method of cooling the electrodes of a spark plug (30) provided in a pre-chamber (34). The spark plug (30) is provided with a fuel inlet (57) formed in a surface of a spark plug body (50). The fuel inlet (57) is configured to receive a supply of gaseous fuel from a fuel supply channel (74) formed in a pre-chamber body (28) to which the spark plug (30) is mounted. The fuel received via the fuel inlet (57) is supplied to an inner space of the spark plug body (50) and discharged via a fuel outlet (55) provided at an end face of the same. The discharged fuel flows past at least part of an electrode assembly (52) of the spark plug (30) to cool the same.