Piston Crown Ridges and Recesses for Combustion Control
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Solution Overview
Problem
Internal combustion engines face challenges in reducing soot emissions due to inefficient combustion processes and flame distribution, leading to increased soot formation and kinetic energy loss.
Innovation Solution
A piston design featuring a piston crown with ridges and recesses that directs the flame towards the center of the cylinder, reducing soot emissions and improving combustion efficiency by controlling the flame's direction and reducing the spray axis angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the flame is allowed to impinge the side section directly without recesses, then the combustion process is simpler, but soot emissions increase due to reduced flame recirculation
Solution Approach 1:
The side section of the piston crown is segmented into multiple ridges that are spaced apart from each other in the circumferential direction. These ridges create distinct flame recirculation zones between them, allowing the flame to be redirected back toward the cylinder center in a controlled manner, thereby reducing soot emissions while maintaining a manageable structural complexity
Solution Approach 2:
The piston crown features localized recesses positioned at specific locations on the side section. These recesses are strategically placed to intercept and redirect the flame upward toward the cylinder head and back toward the cylinder center. The local modification of the side section geometry creates targeted flame recirculation zones that reduce soot emissions without requiring a complete redesign of the entire piston crown
2Productivity
If the spray axis angle is reduced to improve combustion efficiency, then more flame is directed toward the center, but the flame distribution becomes more challenging to control
Solution Approach 1:
The ridges and recesses on the piston crown act as intermediary structures that mediate between the fuel spray and the combustion chamber. When the spray axis angle is reduced, these intermediary features intercept and redirect the flame upward toward the cylinder head and back toward the cylinder center, ensuring proper flame distribution and maintaining combustion efficiency without direct control challenges
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
The piston design effectively reduces soot emissions and enhances combustion efficiency by ensuring a larger portion of the flame is directed towards the center of the cylinder, minimizing kinetic energy loss and optimizing the combustion process.
Implementation Method 1
the flame will be directed towards the protrusions which will direct the flame back towards the centre of the cylinder. Hereby, the amount of soot can be reduced by means of the flame recirculation
Implementation Method 2
When the fuel is ignited in the cylinder, combustion gases present in the cylinder undergo turbulent mixing with the burning fuel, so that a mixture-controlled diffusion flame is formed. The combustion of the fuel/gas mixture in the cylinder gives rise to heat generation, which causes the gas in the cylinder to expand and which hence causes the piston to move in the cylinder
Implementation Method 3
The combustion of the fuel/gas mixture in the cylinder gives rise to heat generation, which causes the gas in the cylinder to expand
Implementation Method 4
combustion gases present in the cylinder undergo turbulent mixing with the burning fuel, so that a mixture-controlled diffusion flame is formed
Implementation Method 5
If the formed soot particles can be brought together with oxidizing substances such as e.g. oxygen atoms, oxygen molecules, hydroxide at sufficiently high temperature for a good oxidation rate, a greater part of the soot particles can be oxidized
Data Source
AI summary
A piston for a cylinder of a combustion engine includes piston crown including a piston bowl formed by an upwardly facing cavity, the piston bowl including a floor section with a central, and a side section, the side section connecting the inner section with an upper surface of the piston crown, wherein the side section is formed with mutually spaced apart ridges protruding towards the apex, and wherein the side section having at least one recess at an upper end of the side section connecting the side section with the upper surface of the piston crown.