Multipoint Ignition Electrode Heat Value Control
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Solution Overview
Problem
In multipoint ignition devices, all electrode pairs are set with identical heat values, leading to some pairs falling below the self-cleaning temperature, causing pollution, while others exceed the pre-ignition temperature, resulting in inconsistent performance.
Innovation Solution
Individual heat values are set for each electrode pair based on their position in the combustion chamber, considering heat transfer from the wall and gas, and heat loss to fresh air, to maintain temperatures within the appropriate range of 450°C to 1000°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all electrode pairs are set with identical heat values, then manufacturing is simplified, but temperature uniformity across electrode pairs deteriorates
Solution Approach 1:
The patent applies local quality by setting different heat values for electrode pairs based on their specific positions in the combustion chamber. Each electrode pair's heat value is individually determined considering its unique thermal environment, including heat transfer from wall surfaces and combustion gases, as well as heat loss to fresh air. This ensures each electrode pair maintains optimal operating temperature for reliable ignition.
2Reliability
If electrode pair temperature is increased above 1000°C, then self-cleaning effect is enhanced, but pre-ignition occurs
Solution Approach 1:
The patent applies parameter changes by precisely controlling the heat value parameters of each electrode pair to maintain operating temperatures within the optimal range of 450°C to 1000°C. By adjusting heat values based on position-specific thermal conditions, the system achieves sufficient self-cleaning effect to prevent carbon buildup while avoiding temperatures that would cause pre-ignition.
3Object-affected harmful factors
If electrode pair temperature is decreased below 450°C, then pre-ignition is prevented, but carbon accumulation causes pollution
Solution Approach 1:
The patent applies parameter changes by setting appropriate heat value parameters for each electrode pair to ensure operating temperatures remain at or above 450°C. This minimum temperature threshold provides sufficient thermal energy to burn off carbon deposits through self-cleaning, preventing pollution while avoiding the harmful effects of pre-ignition that occur at higher temperatures.
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 approach ensures that all electrode pairs operate within the optimal temperature range, preventing pollution and pre-ignition, thereby improving engine performance and reliability.
Implementation Method 1
a plurality of electrode pairs constituting ignition gaps are disposed around a cylinder opening portion such that an air-fuel mixture in a combustion chamber is ignited from the plurality of ignition gaps
Implementation Method 2
the amount of heat received by the electrode pairs from the wall surface of the combustion chamber and the combustion gas
Implementation Method 3
the amount of heat lost to fresh air differ according to the position of the electrode pair
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Respective heat values of a plurality of electrode pairs P1 to P8 are set individually such that the temperatures of all of the plurality of electrode pairs (P1 to P8) are kept within an appropriate temperature range in which a temperature no lower than a self-cleaning temperature is set as a lower limit temperature and a lower temperature than a pre-ignition temperature is set as an upper limit temperature.