Arcuate Piston Crown Indents for Fuel Jet Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Direct injection engines face inefficiencies and increased emissions due to fuel dispersion issues, where fuel jets interact with combustion chamber surfaces, leading to uneven burning, higher temperatures, and heat rejection.
Innovation Solution
The design incorporates a piston crown with arcuate indents that redirect and segregate fuel jets, creating a spiral motion within the combustion chamber, keeping fuel away from cylinder walls and promoting uniform fuel-air mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fuel jets are injected directly into the combustion chamber, then fuel injection is simplified, but fuel disperses unevenly causing localized rich and lean areas
Solution Approach 1:
The arcuate indent is divided into multiple lobes (typically 3-5 lobes spaced around the indent), which segment the incoming fuel jet into multiple separate streams. Each lobe redirects a portion of the fuel at different angles, creating multiple fuel trajectories that distribute fuel more uniformly across the combustion chamber rather than allowing a single concentrated jet to impinge on one location.
2Device complexity
If fuel jets impinge on combustion chamber surfaces, then fuel injection is straightforward, but heat rejection and component temperatures increase
Solution Approach 1:
The arcuate indent introduces a third dimensional aspect to fuel distribution by creating a curved, three-dimensional flow path within the piston crown. Fuel is redirected along the curved surfaces of the lobes, moving it through space in a controlled trajectory that prevents direct impingement on hot surfaces like the cylinder head or piston crown, thereby reducing heat transfer to components.
3Stability of the object's composition
If deflection foils redirect fuel spray radially, then fuel mixing is improved, but fuel migrates toward cylinder walls increasing heat rejection
Solution Approach 1:
Each lobe within the arcuate indent has specifically tailored geometry with different curvature radii and angles optimized for its position. The lobes create localized flow patterns that direct fuel toward the center of the combustion chamber rather than allowing it to migrate outward toward the cylinder walls. This localized control of fuel trajectory prevents wall impingement while maintaining good mixing.
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 solution enhances fuel efficiency, reduces emissions, and maintains lower component temperatures by ensuring uniform fuel-air mixing and minimizing interaction with cylinder surfaces.
Implementation Method 1
the at least one arcuate indent is aligned with the fuel jet centerline and includes two or more lobes... During operation, a single fuel jet provided into the at least one arcuate indent is separated into a plurality of fuel jet portions
Implementation Method 2
creating a spiral motion within the combustion chamber
Implementation Method 3
a recirculation surface having a concave shape and extending along a spiral direction adjacent the entry surface
Implementation Method 4
a wall extending generally in an axial direction and disposed radially along the recirculation surface
Data Source
AI summary
A piston has a piston crown portion forming at least one arcuate indent in aligned fashion with a fuel jet discharged into a combustion chamber. Each arcuate event forms lobes, which separate the fuel jet into portions, or is tiered, to accommodate fuel jet portions being discharged into the combustion chamber at different times. Each lobe or tier includes an entry surface, a recirculation surface and a wall to separate it from adjacent lobes or tiers, respectively.