Spark Plug Cap Projections for Jet Velocity and Volume
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Solution Overview
Problem
The existing spark plug design faces challenges in achieving a sufficient volume of jet with an increased range due to the trade-off between jet velocity and volume, where larger holes reduce pressure and velocity, and smaller holes increase pressure but decrease volume, leading to potential high-speed combustion failures.
Innovation Solution
The spark plug features a cap portion with projections on the inner surface of the through hole, which extend in the direction of the hole, reducing drag and allowing for increased jet velocity without reducing hole size, thereby enhancing the jet's range and volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of the through hole in the cap portion is increased, then the volume of the jet increases, but the pressure in the pre-chamber at the time of ignition decreases, leading to reduced jet velocity and range
Solution Approach 1:
The invention changes the geometric parameters of the through hole by introducing projections on the inner surface that extend in the extending direction of the hole. This modifies the flow characteristics and drag properties of the hole, allowing it to maintain high jet velocity while accommodating a larger hole size for increased jet volume.
Solution Approach 2:
The invention adds a third dimension to the through hole structure by introducing projections that extend along the length of the hole. This transforms the simple cylindrical hole into a more complex three-dimensional structure with varying cross-sectional area, enabling simultaneous optimization of flow volume and velocity.
2Speed
If the size of the through hole in the cap portion is decreased, then the pressure in the pre-chamber at the time of ignition increases, leading to increased jet velocity and range, but the volume of the jet decreases
Solution Approach 1:
The invention modifies the geometric parameters of the through hole by adding projections that extend in the extending direction. This changes the effective flow area and drag characteristics, allowing the system to achieve high jet velocity without sacrificing jet volume, thus resolving the contradiction between velocity and volume.
3Quantity of substance
If the size of the through hole is increased to generate sufficient jet volume, then the jet range decreases due to reduced velocity, but maintaining a smaller hole size increases velocity while limiting the volume of combustible air-fuel mixture that can be ignited
Solution Approach 1:
The invention changes the geometric parameters of the through hole structure by introducing projections, which modifies the flow dynamics to maintain high velocity while accommodating larger hole size for increased jet volume and extended range.
Solution Approach 2:
By introducing projections that extend along the length of the through hole, the invention adds dimensional complexity that enables the hole to simultaneously provide sufficient opening area for volume and maintain flow coherence for range.
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 generates a jet with increased velocity and range, ensuring a sufficient volume of combustible air-fuel mixture is ignited efficiently, reducing the risk of high-speed combustion failures and pre-ignition issues.
Implementation Method 1
The projections serve to reduce the drag created when a gas flow passes through the through hole
Implementation Method 2
The spark plug ignites the combustible air-fuel mixture that has reached a spark gap, so that the combustible air-fuel mixture is combusted to generate an expansion pressure that causes a gas flow including flame to be injected into the combustion chamber
Data Source
AI summary
A spark plug capable of generating a sufficient volume of jet with an increased range is provided. The spark plug includes a metal shell having a tubular shape; a center electrode retained in the metal shell in an insulated manner; a ground electrode that is electrically connected to the metal shell and that defines a spark gap between the center electrode and an end portion of the ground electrode; and a cap portion that covers the center electrode and the end portion of the ground electrode from the front in a region in front of the metal shell and in which a through hole is formed. The cap portion includes a plurality of projections on an inner surface of the through hole. The projections extend in an extending direction in which the through hole extends.