Piston Top Land Partial Grooves for Complete Fuel Combustion
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Solution Overview
Problem
Conventional piston designs for internal combustion engines result in high concentrations of uncombusted fuel in exhaust gas due to inadequate combustion of the air-fuel mixture in the groove.
Innovation Solution
A piston with a top land featuring a plurality of partial grooves that extend circumferentially, with depths continuously reducing from the center to the ends, and side surfaces that are parallel or have a flat upper and sloped lower surface, facilitating complete combustion of the air-fuel mixture by directing the flame from both ends into the center of the groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a groove is formed in the top land of the piston to store uncombusted fuel, then the fuel can be retained in the groove, but the concentration of uncombusted fuel in exhaust gas increases
Solution Approach 1:
The continuous groove in the top land is divided into multiple segmented grooves. Each groove has a specific depth profile (deeper at center, shallower at ends) that allows flame to be drawn from both ends into the center, ensuring complete combustion of the air-fuel mixture stored in each groove segment, thereby reducing uncombusted fuel in exhaust gas
Solution Approach 2:
Different regions of the groove are given different depths - the center portion has greater depth while the end portions have reduced depth. This local variation in groove depth creates optimal conditions for flame propagation and complete combustion in the fuel-rich region, converting the harmful fuel concentration into beneficial combustion efficiency
2Quantity of substance
If the groove depth is increased to store more fuel, then fuel storage capacity improves, but combustion completeness deteriorates
Solution Approach 1:
The groove depth is varied locally along its length, with the center having maximum depth for fuel storage and the ends having reduced depth. This creates a depth gradient that guides flame propagation from the shallower ends into the deeper center region, ensuring complete combustion of the stored fuel while maintaining optimal fuel storage capacity
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 configuration significantly reduces the concentration of uncombusted fuel in exhaust gas, improving combustion efficiency and reducing emissions such as CO and NOx, while also minimizing lubricating oil residue and autoignition issues, thereby enhancing engine reliability and quietness.
Implementation Method 1
the flame flows in such a manner that the flame is drawn from both ends of the partial groove into the center of the partial groove
Implementation Method 2
the flame flows in such a manner that the flame is drawn from both ends of the partial groove into the center of the partial groove
Implementation Method 3
assuredly combust an air-fuel mixture of air and a fuel in the partial groove
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A piston of an internal combustion engine includes a top land with a plurality of partial grooves formed therein, the plurality of partial grooves extending in a circumferential direction and being spaced apart from each other in the circumferential direction. Each of the plurality of partial grooves is formed such that a depth of each partial groove is continuously reduced from a center of the partial groove toward both ends of the partial groove.