Variable Coil Diameter Valve Spring for Intake Port Flow
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Solution Overview
Problem
Internal combustion engines face challenges in reducing fluid disturbance and size while maintaining the load-bearing capacity of valve springs, as larger coil diameters are needed for sufficient load-bearing capacity but result in protrusions that disrupt air flow and increase engine size.
Innovation Solution
The engine design features a valve spring with a closely-wound section near the port and a sparsely-wound section further away, allowing for a smaller coil diameter near the port, reducing protrusions and fluid disturbance, and maintaining load-bearing capacity through a gradual coil diameter decrease and use of a flat washer valve spring seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a larger coil outer diameter is used for the valve spring, then the load-bearing capacity is improved, but the protrusion into the port increases causing fluid disturbance and increased engine size
Solution Approach 1:
The valve spring is designed with a non-uniform coil structure where the coil outer diameter varies along the axial direction. Specifically, the coil outer diameter is smaller at the port side and larger at the opposite side, allowing the spring to have sufficient load-bearing capacity overall while minimizing protrusion into the port to reduce fluid disturbance
Solution Approach 2:
Instead of using a uniform coil diameter in one dimension, the invention introduces dimensional variation along the axial direction of the spring. This creates a tapered or stepped coil structure that optimizes both load-bearing capacity and port flow characteristics by distributing the diameter variation along the spring's length
2Strength
If a larger coil outer diameter is used for the valve spring, then the load-bearing capacity is improved, but the engine size increases
Solution Approach 1:
The valve spring employs varying coil outer diameter along its axial length, with smaller diameter sections positioned to minimize overall envelope dimensions. This allows the spring to maintain adequate load-bearing capacity through strategic diameter distribution rather than uniformly large dimensions, thereby reducing engine size
3Object-affected harmful factors
If the coil outer diameter is reduced to minimize protrusion, then fluid disturbance is reduced, but the load-bearing capacity decreases
Solution Approach 1:
The valve spring features a non-uniform coil structure with different outer diameters at different axial positions. The smaller coil diameter is positioned at the port side to reduce fluid disturbance, while the larger coil diameter at the opposite side compensates for the reduced load-bearing capacity, maintaining overall spring strength
Solution Approach 2:
The invention compensates for the reduced load-bearing capacity from smaller coil diameter by utilizing the axial dimension. The varying diameter along the spring's length allows the larger diameter section to provide additional structural support and load-bearing capability, balancing the trade-off with port flow requirements
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 minimizes fluid disturbance, increases intake air flow, and reduces engine size without compromising load-bearing capacity, enhancing engine performance and efficiency.
Implementation Method 1
The valve spring is a compression coil spring placed between the first valve spring seat and the second valve spring seat and supported on the first valve spring seat and the second valve spring seat
Data Source
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AI summary
An internal combustion engine 5 includes an intake valve spring 60 including a closely-wound section 62 and a sparsely-wound section 63. The closely-wound section 62 is provided so that elemental wire portions thereof are closely in contact with each other in the direction of the coil axial line L1 while the internal combustion engine 5 is inoperative. The sparsely-wound section 63 is provided so that elemental wire portions thereof are spaced apart from each other in the direction of the coil axial line L1 while the internal combustion engine 5 is inoperative. The coil outer diameter D62 of at least a part of the closely-wound section 62 is smaller than the coil outer diameter D63 of at least a part of the sparsely-wound section 63.