Asymmetric Spark Plug Prechamber Ignition
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Solution Overview
Problem
Existing internal combustion engines with spark plugs do not effectively improve the ignition of the air-fuel mixture in the prechamber, as they do not consider the extension of the spark to enhance ignition efficiency.
Innovation Solution
The design includes a spark plug with a prechamber-defining portion that has spray holes with specific angles to direct gas flow, recirculating the spark from the main combustion chamber into the prechamber, improving the ignition of the air-fuel mixture by positioning the spark gap upstream of the plug center axis in the gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spark gap is positioned at the plug center axis, then the structure is simple and easy to manufacture, but the ignition efficiency of the air-fuel mixture in the prechamber is insufficient
Solution Approach 1:
The spark gap is deliberately positioned asymmetrically upstream of the plug center axis in the gas flow direction, rather than at the center. This asymmetric positioning allows the spark to be carried by the gas flow into the prechamber, significantly improving ignition efficiency of the air-fuel mixture while maintaining a relatively simple overall structure.
Solution Approach 2:
The spray holes are designed with specific angles (greater than 90° on the base end side) to pre-direct the gas flow toward the upstream region where the spark gap is located. This preliminary flow direction ensures that the spark generated at the spark gap is immediately carried into the prechamber by the angled gas flow, enhancing ignition before the main combustion process begins.
2Reliability
If the spray holes are designed with specific angles to direct gas flow, then the spark extension and ignition efficiency are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The spray holes are designed with a specific angular parameter (greater than 90° on the base end side relative to the prechamber inner wall). This parameter change in the spray hole geometry creates the necessary gas flow angle to carry the spark into the prechamber, improving combustion stability while providing a clear design criterion for manufacturing.
3Productivity
If the spark gap is arranged upstream of the plug center axis, then the spark is effectively extended into the prechamber by gas flow, but the gas flow pattern becomes more complex
Solution Approach 1:
The invention utilizes the existing gas flow (pneumatic field) within the combustion chamber and prechamber to carry the spark from the spark gap into the prechamber. By positioning the spark gap upstream and designing the spray holes to angle toward the upstream region, the natural gas flow dynamics are harnessed to extend the spark without requiring additional mechanical components, thus improving ignition speed while limiting the increase in overall system 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 configuration enhances the ejection of flames from the spray holes into the main combustion chamber, improving ignitability and stability of combustion, as demonstrated by increased spark extension distance and reduced variance in combustion coefficients.
Implementation Method 1
a plurality of spray holes which communicate between the prechamber and a main combustion chamber of the internal combustion engine. At least one of the spray holes is an upstream spray hole which is arranged upstream of a plug center axis in a gas flow within the main combustion chamber
Implementation Method 2
a center electrode which is retained in the porcelain insulator and protrudes from a top end of the porcelain insulator; a ground electrode which is located outside the center electrode and faces an outer periphery of the center electrode to define a spark gap between itself and the center electrode
Implementation Method 3
The internal combustion engine works to ignite air-fuel mixture in the prechamber to generate flame. The flame occurring in the prechamber is jetted from spray holes communicating between the prechamber and a main combustion chamber
Data Source
AI summary
A spark plug includes a housing, a porcelain insulator, a center electrode, a ground electrode, and a prechamber-defining portion. The prechamber-defining portion has a prechamber formed therein. The prechamber-defining portion has a plurality of spray holes. At least one of the spray holes is an upstream spray hole which is arranged upstream of a plug center axis in a gas flow within a main combustion chamber and designed such that and an angle which an extension in an opening direction makes with an inner wall surface of the prechamber is selected to be larger than 90°. A spark gap is formed upstream of a plug center axis in the gas flow within the main combustion chamber.