Piston Cooling Channel Constriction for Heat Transfer
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Solution Overview
Problem
Modern internal combustion engine pistons face challenges in optimizing cooling, particularly in the piston crown area, due to high mechanical and thermal loads, where existing designs do not efficiently distribute and accelerate coolant for effective heat transfer.
Innovation Solution
The piston features a narrowing in the cooling channel, combined with a dome-shaped ceiling, which accelerates and directs coolant into a circular flow, increasing the heat transfer coefficient by forcing the coolant to interact repeatedly with the channel walls, thereby enhancing cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant flow is increased through the cooling channel, then cooling efficiency improves, but flow velocity distribution becomes uneven and hot spots remain
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the cooling channel, specifically introducing a constriction (reduced cross-sectional area) at a specific location. This changes the flow parameters (velocity, pressure) locally to achieve better overall cooling. The constriction causes acceleration of coolant flow according to the continuity equation, improving velocity distribution and heat transfer efficiency.
Solution Approach 2:
The patent applies local quality by creating a localized constriction in the cooling channel rather than uniformly changing the entire channel geometry. This local modification creates a specific flow pattern where coolant is accelerated at the constriction and then distributes more effectively to hot spots, achieving improved cooling where needed without redesigning the entire system.
2Temperature
If cooling channel geometry is modified to improve flow distribution, then heat transfer coefficient increases, but channel design complexity increases
Solution Approach 1:
The patent modifies only a specific local region of the cooling channel by introducing a constriction, rather than redesigning the entire channel geometry. This localized modification achieves improved heat transfer coefficient through better flow velocity distribution while keeping the overall channel design relatively simple and manageable.
Solution Approach 2:
The patent changes specific geometric parameters (cross-sectional area) at a localized position to achieve the desired flow characteristics. This approach allows for improved heat transfer without requiring complete redesign of the cooling channel, thus limiting the increase in design complexity.
3Area of stationary object
If coolant flow path is extended to cover more surface area, then cooling coverage improves, but flow velocity decreases reducing heat transfer efficiency
Solution Approach 1:
The patent introduces a constriction that changes the flow velocity parameter locally. By reducing the cross-sectional area at the constriction, the coolant velocity increases according to the continuity equation, compensating for the velocity loss that would occur in extended flow paths. This allows for both extended coverage and maintained heat transfer efficiency.
Solution Approach 2:
The constriction creates a periodic acceleration pattern in the coolant flow - the coolant is accelerated as it passes through the constriction and then decelerates afterward, creating repeated cycles of high-velocity flow that enhance heat transfer throughout the extended cooling channel path.
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 significantly improves cooling efficiency by accelerating and mixing coolant, ensuring it interacts more frequently with hot areas, leading to enhanced heat transfer and reduced thermal stress on the piston.
Implementation Method 1
The present invention is based on the continuity equation of fluid dynamics, according to which a narrowing of the flow cross-section in flowing fluids leads to an increase in the flow velocity.
Implementation Method 2
The cooling channel cover is essentially dome-shaped. This ensures that the coolant is forced into a circular flow in the region of the cooling channel cover, so that it interacts with the wall of the cooling channel several times per piston stroke.
Implementation Method 3
This increases the heat transfer coefficient between the cooling channel wall and the coolant, thus significantly improving the cooling of the piston according to the invention.
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a piston (10, 110, 210) for an internal combustion engine, comprising a piston head (11, 111, 211) and a piston skirt, said piston head (11, 111, 211) having a circumferential ring section (15, 115, 215) and a circumferential cooling channel (16, 116, 216) in the region of the ring section (15, 115, 215). The cooling channel has a cooling channel floor (17, 117, 217) and a cooling channel ceiling (18, 118, 218). According to the invention, the cooling channel (16, 116, 216) has a narrowing (20, 120, 220).