Multipoint Ignition Device Heat Shield for Temperature Control
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Solution Overview
Problem
In multipoint ignition devices, the electrode pair temperature is either too low for carbon deposition or excessively high for pre-ignition, necessitating a method to adjust the heat value effectively.
Innovation Solution
A multipoint ignition device with an interposed member between the cylinder head and block, featuring intermediate members connected to electrode pairs, where the exposure area of these members is adjustable to control the heat received from combustion gases, allowing for heat value adjustment by modifying the projection amount, width, height, or surface area of the intermediate members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode pair temperature is lowered to prevent pre-ignition, then carbon deposition occurs and spark generation fails, but if the temperature is raised to prevent carbon deposition, then pre-ignition occurs
Solution Approach 1:
The patent introduces an intermediate member (heat shield) positioned between the electrode pair and the combustion chamber as a mediating element. This heat shield absorbs excess heat from the combustion gases and redirects it away from the electrode pair, preventing the electrode temperature from rising too high and causing pre-ignition, while still allowing sufficient heat to reach the electrode to prevent carbon deposition and maintain reliable spark generation.
Solution Approach 2:
The patent changes the thermal parameters of the ignition system by introducing a heat shield with specific thermal properties. The heat shield's thickness, material composition, and positioning are optimized to control the heat transfer rate, thereby adjusting the electrode pair temperature to an optimal range that prevents both carbon deposition and pre-ignition.
2Object-generated harmful factors
If the electrode pair temperature is raised to prevent carbon deposition, then pre-ignition occurs, but if the temperature is lowered to prevent pre-ignition, then carbon deposition occurs
Solution Approach 1:
The heat shield serves as an intermediary that selectively filters heat transfer to the electrode pair. It blocks excessive heat that would cause pre-ignition while permitting sufficient heat transfer to maintain electrode temperature above the carbon deposition threshold, thus preserving ignition performance.
Solution Approach 2:
By modifying the thermal parameters through the heat shield design (material selection, thickness, geometry), the patent optimizes the electrode pair temperature within a specific range that simultaneously prevents pre-ignition and maintains reliable ignition performance.
3Temperature
If the heat value of the ignition device is increased to prevent carbon deposition, then pre-ignition occurs, but if the heat value is decreased to prevent pre-ignition, then carbon deposition occurs
Solution Approach 1:
The heat shield acts as a thermal intermediary that decouples the relationship between combustion chamber temperature and electrode pair temperature. It allows the system to operate with high combustion temperatures while maintaining electrode pair temperature within the optimal range, preventing both carbon deposition and pre-ignition.
Solution Approach 2:
The patent changes the thermal parameter distribution in the ignition system by introducing the heat shield, which creates a controlled temperature gradient. This allows optimization of electrode pair temperature independently from combustion chamber temperature, eliminating the need to choose between preventing carbon deposition and avoiding pre-ignition.
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 method enables precise adjustment of the heat value, preventing carbon deposition and pre-ignition by optimizing the temperature of the electrode pairs, thereby improving ignition performance and engine efficiency.
Implementation Method 1
by adjusting the exposure area of the intermediate member, the amount of heat received by the multipoint ignition device from the combustion gas can be adjusted
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
A multipoint ignition device comprises: a head gasket (1) interposed between a cylinder head and a cylinder block of an engine, having an opening (3) in a position corresponding to a cylinder opening portion; and a plurality of intermediate members (6) connected respectively to a plurality of electrode pairs (2) and held by the head gasket (1). A part of at least one of the plurality of intermediate members (6) is exposed to the opening (3).