Square-Recess Piston Structure for Methanol Engine Tumble Flow
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Solution Overview
Problem
Current engine combustion chambers are not optimized for methanol engines, leading to low combustion efficiency, structural inefficiencies, and increased weight and noise due to the piston's design, which affects NVH performance.
Innovation Solution
A piston design with a recess and two protruding structures, featuring a square cross-section perimeter, enhances tumble flow and suppresses secondary airflow, while reducing compression height for structural compactness and improved NVH performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the combustion chamber volume is concentrated at the piston recess, then the piston structure can accommodate the combustion chamber, but the compression height becomes large, resulting in increased engine weight and reduced structural compactness
Solution Approach 1:
The patent transitions from a traditional deep recess design to a shallow recess with extended side walls, effectively redistributing the combustion chamber volume from the vertical dimension to the horizontal dimension. This dimensional shift reduces the compression height and piston weight while maintaining the required combustion chamber volume.
Solution Approach 2:
The combustion chamber is segmented into multiple regions: a shallow recess on the piston top surface and extended side walls that define additional combustion space. This segmentation allows the combustion chamber volume to be distributed across different spatial zones, reducing the need for a deep recess and thereby reducing piston compression height and weight.
2Ease of manufacture
If the combustion chamber structure is based on traditional diesel engine design, then the structural design is simplified, but the tumble flow ratio is insufficient, resulting in low combustion efficiency for methanol engines
Solution Approach 1:
The patent applies local quality by creating specific geometric features (square cross-section recess with extended side walls) in localized areas of the piston. These localized structural modifications are designed to generate optimal tumble flow in the combustion chamber while maintaining the overall simplicity of the piston structure and manufacturing processes.
3Volume of moving object
If the piston compression height is large, then the piston can accommodate the combustion chamber, but the overall engine structural size is not compact and the inertia is increased, affecting NVH performance
Solution Approach 1:
The patent redistributes the combustion chamber volume from the vertical dimension (recess depth) to the horizontal dimension (side wall extension), effectively reducing the piston compression height while maintaining the required combustion chamber volume. This dimensional transformation directly addresses the contradiction between combustion chamber volume and compression height.
Data Source
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AI summary
A piston (100), the top of the piston (100) is provided with a recess (200) and two protruding structures (300), the recess (200) is provided between the two protruding structures (300), and the outer periphery of the cross section of the recess (200) perpendicular to the height direction of the piston is square. The piston (100) can increase the tumble flow of a combustion chamber structure of a methanol engine and improve the combustion efficiency of the methanol engine. A combustion chamber structure (910) and an engine with the piston (100) are also provided.