Otto Engine Piston Depression Bulge Combustion Control
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Solution Overview
Problem
Existing piston designs in internal combustion engines face challenges in optimizing combustion efficiency, leading to potential knocking or self-ignition, which can damage the engine and reduce its lifespan, while also resulting in inefficient fuel consumption.
Innovation Solution
The piston features a surface on the combustion chamber side with a depression and one or more bulges, where the bulge depth is less than the depression depth, and the bulge edge is inclined, promoting rapid and homogeneous mixing of the air-fuel mixture through acceleration edges, thereby controlling combustion and preventing knocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional piston design is used, then the structure is simple, but combustion efficiency is insufficient leading to knocking or self-ignition
Solution Approach 1:
The piston crown is segmented into multiple functional zones: a depression (bowl) for fuel injection and a bulge extending from the depression edge. This segmentation allows different regions to perform specific combustion functions - the depression for fuel atomization and the bulge for controlling combustion progression, thereby preventing knocking while maintaining structural feasibility
Solution Approach 2:
Different regions of the piston crown are given different geometric properties: the depression provides a localized cavity for fuel injection, while the bulge creates a specific flow pattern. These local quality variations optimize combustion in each zone, improving overall combustion control without requiring complete redesign of the entire piston
2Productivity
If combustion is accelerated, then fuel consumption improves, but mechanical stress increases causing damage
Solution Approach 1:
The depression and bulge geometry are designed to pre-condition the fuel-air mixture before combustion. The depression facilitates preliminary fuel atomization and mixing, while the bulge prepares the flow pattern for controlled combustion propagation. This preliminary action ensures rapid yet controlled combustion that accelerates the process without creating damaging pressure spikes
3Stability of the object's composition
If the bulge depth is increased, then combustion homogeneity improves, but the risk of self-ignition increases
Solution Approach 1:
The invention optimizes the bulge depth as a critical parameter, setting it to extend from the depression edge but not exceeding certain limits. This parameter optimization creates the right balance: deep enough to promote mixture homogeneity and controlled combustion propagation, but not so deep as to create conditions for self-ignition. The specific geometric parameters are tuned to achieve the desired combustion characteristics
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 design enhances combustion efficiency by ensuring even and quick combustion across the combustion chamber, reducing mechanical stress, and optimizing energy yield while preventing knocking, thus extending engine lifespan and improving fuel efficiency.
Implementation Method 1
the bulge edge is inclined, promoting rapid and homogeneous mixing of the air-fuel mixture through acceleration edges
Data Source
Figure 1a~1c
Figure 2~3
Figure 4~5
AI summary
The invention relates to a piston (100) for an internal combustion engine. The piston has a surface on the combustion side (110) wherein a depression (130) having a depression edge (140) and a depression floor (132) is arranged in the surface and the depression has a maximum depth of tmax in the axial direction of the piston, measured from the combustion side surface. The combustion side surface furthermore has at least one protrusion (150) that is arranged on a section of the depression edge (142) and has a depth taus, wherein the depth taus of the protrusion is smaller than the depth of the depression tmax in the axial direction of the piston.