Pre-Chamber Engine Flame Momentum Control
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Solution Overview
Problem
Strong knock, a form of abnormal combustion causing noise and potential engine damage, occurs in pre-chamber ignition systems, particularly at high load and high rotation, hindering thermal efficiency and reliability.
Innovation Solution
The engine is configured with a specific bore/stroke ratio, compression ratio, and number of through-holes in the partition wall to control the momentum of the flame injected from the sub-chamber, ensuring it falls within an optimal range to suppress strong knock while maintaining good fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the momentum of the flame injected from the sub-chamber is increased to improve combustion speed, then flame propagation becomes faster and combustion efficiency improves, but strong knock occurs due to excessively fast flame propagation causing abnormal combustion
Solution Approach 1:
The patent applies parameter changes by precisely controlling the momentum of the flame injected from the sub-chamber within a specific range. This involves adjusting geometric parameters (bore/stroke ratio, sub-chamber volume, number of through-holes) to achieve optimal flame momentum that ensures fast combustion without causing strong knock, thereby resolving the contradiction between combustion speed and knock suppression
Solution Approach 2:
The patent applies dynamics by making the flame injection process controllable and adaptive. The system dynamically balances the flame momentum to be sufficiently high for rapid combustion propagation but controlled enough to prevent abnormal combustion and strong knock, achieving both high productivity and reliability
2Loss of energy
If the compression ratio is increased to improve thermal efficiency, then more energy is extracted from combustion, but strong knock becomes more likely to occur
Solution Approach 1:
The patent applies parameter changes by optimizing the compression ratio within a specific range and combining it with controlled flame momentum from the pre-chamber ignition system. This allows the engine to achieve high thermal efficiency through increased compression ratio while the controlled flame propagation prevents strong knock, resolving the contradiction between energy efficiency and reliability
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 effectively suppresses strong knock at high load and high rotation, improving thermal efficiency and maintaining stable combustion with good fuel efficiency.
Implementation Method 1
ignites an air-fuel mixture in the sub-chamber to inject flame through the openings of the partition wall to the main chamber
Implementation Method 2
burns the air-fuel mixture in the main chamber
Data Source
AI summary
To effectively suppress strong knock that occurs in the operating region of high load and high rotation in a specific engine having a pre-chamber in a combustion chamber, the engine includes a piston that defines a combustion chamber together with a cylinder block and a cylinder head. The combustion chamber includes a sub-chamber and a main chamber separated from the sub-chamber by a pre-chamber. The specific ratio obtained by dividing a bore/stroke ratio of a cylinder by the volume of the sub-chamber is greater than or equal to 6.6 cm−3 and less than or equal to 57.6 cm−3.