Piston Crown with Central Mound and Inclined Slot for Fuel Mixing
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Solution Overview
Problem
Direct injection of fuels like natural gas and diesel in engines results in limited time for adequate mixing with air, leading to incomplete combustion, reduced engine efficiency, increased emissions, and maintenance needs.
Innovation Solution
A piston design featuring a central chamber with a passageway and a central mound that directs fuel flow from the chamber towards the outer circumference, enhancing mixing with air through a combination of inclined slots and a bowl configuration to improve fuel-air homogenization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct injection of fuel is used in the cylinder, then fuel injection efficiency is improved, but fuel-air mixing time is reduced
Solution Approach 1:
The piston crown is segmented into multiple functional zones including a central chamber, a bowl extending from a central mound, and an inclined slot. This segmentation creates distinct regions for fuel injection, initial mixing, and secondary mixing, allowing the fuel injection process to be divided into stages that occur sequentially within the limited time available, thereby improving overall fuel-air mixing efficiency without sacrificing injection speed
Solution Approach 2:
The invention introduces a vertical dimension to fuel-air mixing by creating a central chamber recessed into the piston crown with a bowl extending upward toward the crown surface. This three-dimensional structure adds depth to the mixing process, allowing fuel to be injected into the central chamber and then mixed both radially and vertically, effectively increasing the mixing volume and time without requiring additional horizontal space or extending the injection duration
2Speed
If direct injection of fuel is used in the cylinder, then injection speed is improved, but combustion completeness deteriorates
Solution Approach 1:
The inclined slot is positioned and angled to pre-direct the fuel spray toward the outer circumference of the piston crown before the main combustion event. This preliminary action ensures that fuel begins mixing with air immediately upon injection and is progressively distributed across the combustion chamber, creating a more homogeneous fuel-air mixture prior to ignition and ensuring more complete combustion even at high injection speeds
Solution Approach 2:
Different regions of the piston crown are designed with distinct geometries to perform specialized functions: the central chamber provides a confined space for initial fuel accumulation and mixing, the bowl extending from the central mound creates a vortex flow pattern for enhanced mixing, and the inclined slot directs fuel toward the periphery. This local differentiation of functional qualities ensures that each region contributes optimally to achieving complete combustion
3Productivity
If direct injection of fuel is used in the cylinder, then fuel delivery efficiency is improved, but emission levels increase
Solution Approach 1:
The combination of the central chamber, bowl, and inclined slot creates a continuous fuel-air mixing pathway that operates throughout the entire combustion cycle. Fuel injected into the central chamber is continuously mixed with air as it moves through the bowl and along the inclined slot toward the combustion chamber, ensuring that the fuel delivery process remains coupled with ongoing mixing and combustion preparation, thereby minimizing unburned hydrocarbons and other emissions
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 fuel-air mixing, leading to improved combustion efficiency, reduced emissions, and lower maintenance requirements by ensuring more complete fuel burn within the engine cylinder.
Implementation Method 1
The slot is adapted to allow flow of a fuel from the central chamber towards the outer circumference of the crown
Data Source
AI summary
A piston for an engine is provided. The piston includes a body having a crown disposed about a central axis. The crown includes an inner circumference and an outer circumference. The piston includes a central chamber transversely disposed within the body and recessed with respect to the crown. The piston includes a central mound disposed within the central chamber about the central axis. The piston also includes a bowl extending from the central mound towards the crown. The piston further includes a passageway provided on the inner circumference of the crown. The passageway includes a slot defined by a first surface inclined at a first angle with respect to the central axis. The slot is adapted to allow flow of a fuel from the central chamber towards the outer circumference of the crown.